Grouting has been the most effective approach to mitigate water inrush disasters in underground engineering due to its ability to plug groundwater and enhance rock strength.Nevertheless,there is a lack of potent numer...Grouting has been the most effective approach to mitigate water inrush disasters in underground engineering due to its ability to plug groundwater and enhance rock strength.Nevertheless,there is a lack of potent numerical tools for assessing the grouting effectiveness in water-rich fractured strata.In this study,the hydro-mechanical coupled discontinuous deformation analysis(HM-DDA)is inaugurally extended to simulate the grouting process in a water-rich discrete fracture network(DFN),including the slurry migration,fracture dilation,water plugging in a seepage field,and joint reinforcement after coagulation.To validate the capabilities of the developed method,several numerical examples are conducted incorporating the Newtonian fluid and Bingham slurry.The simulation results closely align with the analytical solutions.Additionally,a set of compression tests is conducted on the fresh and grouted rock specimens to verify the reinforcement method and calibrate the rational properties of reinforced joints.An engineering-scale model based on a real water inrush case of the Yonglian tunnel in a water-rich fractured zone has been established.The model demonstrates the effectiveness of grouting reinforcement in mitigating water inrush disaster.The results indicate that increased grouting pressure greatly affects the regulation of water outflow from the tunnel face and the prevention of rock detachment face after excavation.展开更多
The chloride penetration resistance of cement-based grout materials was improved by nano-silica emulsion.Specimens of mixtures containing different nano-silica particles or emulsions were exposed in sodium chloride so...The chloride penetration resistance of cement-based grout materials was improved by nano-silica emulsion.Specimens of mixtures containing different nano-silica particles or emulsions were exposed in sodium chloride solutions of specific concentrations with different test ages.Hardened properties of the mixes were assessed in terms of weight loss and compressive strength.X-ray diffraction(XRD)and scanning electron microscopy(SEM)of mixes were performed to analysis the phase evolution and microstructure.The results demonstrated that the introduction of nano-SiO_(2) emulsion significantly decreased the compressive strength loss and calcium hydroxide(CH)crystal content of hydration production,and then enhanced the resistance of cement-based grouting materials to chloride ion penetration.This improvement derives from the filling and pozzolanic effects of nano-SiO_(2) particles,which were incorporated via an emulsion and attributed to a well dispersion in grouting matrix.展开更多
Appropriate determination of the mix ratios of cement grouts is of vital importance to the quality of rock grouting and the risk reduction of groundwater inflow.The behavior of grout,often highly temperature dependent...Appropriate determination of the mix ratios of cement grouts is of vital importance to the quality of rock grouting and the risk reduction of groundwater inflow.The behavior of grout,often highly temperature dependent,is likely to be affected by the elevated ground temperature in deep rock masses.This paper aims to experimentally gain insights into the effects of elevated ground temperatures on the properties of cement grout in fresh and hardened states in deep rock grouting.The results revealed that a temperature of 35°C is crucial for changes in the properties of thick cement grout with a water–cement ratio of less than 0.8.When the temperature is up to 35°C,there can be significant improvements in rheological parameters,acceleration of grout setting,and increase in the rheological time dependence of thick cement grout;however,there may also be a slight impact on the initial grout flowability and the nature of shear thinning.The high temperature may still improve the stability of fresh cement grout and also improve the porosity and creep deformation of hardened cement grout considerably.The proposed constitutive model that couples the Burgers model with a fractional derivativebased Abel dashpot in the series can be used to characterize the creep behavior of hardened cement grout appropriately.The paper provides a valuable reference for optimization of mixture design of cement grouts,thus enhancing deep rock grouting quality and improving safety.展开更多
Curtain grouting projects are characterized by their large scale and complexity,presenting significant challenges for real-time prediction of grout penetration using traditional methods.This study introduces an intell...Curtain grouting projects are characterized by their large scale and complexity,presenting significant challenges for real-time prediction of grout penetration using traditional methods.This study introduces an intelligent prediction method for grouting in fractured rock masses based on three core principles:integration of multi-source input features,fracture voxel modeling,and shortest path in sequential grouting.Three categories of data(geological structure data,grouting environmental data,and grouting operation data in the concept of a grouting geological model)are integrated and served as multi-source structured data in the intelligent prediction of grouting.A voxelization model quantifies the spatial characteristics of fractures,with voxel size optimized for capturing grouting paths.A shortest path algorithm based on a hierarchical solution is then developed to calculate grout penetration distances in the process of sequential grouting.A complete analysis framework is established,from the voxelization of the fracture network model to precise voxel classification,ultimately achieving an accurate prediction of grout penetration.The method demonstrates excellent performance on the test set,with validation against numerical methods in single-fracture and sequential grouting scenarios confirming its accuracy and prediction efficiency as hundreds of times faster than numerical methods.Application to the Dongzhuang hydraulic project’s grouting test area further validates its effectiveness in multi-hole grouting scenarios.展开更多
Grouting injection is a vital technique for addressing the challenges of high stress and significant deformation in the surrounding rock during deep mining operations,playing a crucial role in promoting green and low-...Grouting injection is a vital technique for addressing the challenges of high stress and significant deformation in the surrounding rock during deep mining operations,playing a crucial role in promoting green and low-carbon extraction methodologies.In this study,grouting reinforcement processes were examined by conducting grouting experiments on a fractured rock with varying negative pressures(0-100 kPa),followed by uniaxial compression testing of the grout-reinforced bodies.This investigation explored the diffusion patterns of grout under negative pressure and established a constitutive model of damage-bearing capacity for bodies reinforced by negative pressure grouting.It further studied the enhancement effect of negative pressure on the load-bearing capacity of the reinforced bodies and analyzed the instability mechanism of damage and failure in these bodies.The results indicated that the diffusion of grout under negative pressure is influenced by four types of forces,which alter the extent of grout diffusion within the fractured rock mass.Introducing a damage constitutive model that serially connects pore and framework elements characterizes the damage and failure behavior of groutreinforced bodies under different negative pressures.As the negative pressure increases,changes in porosity,water-to-cement ratio,and admixture quantity occur in the grout-reinforced specimens,with the strength mean curve showing a trend of first increasing and then decreasing,reaching a threshold at a negative pressure of 60 kPa.With increasing negative pressure,the negative pressure damage variable decreases and then increases,and the stronger the interfacial microelement connections caused by the negative pressure,the greater the bearing capacity,ultimately manifesting in different failure modes.展开更多
The ongoing operation of subway systems makes existing tunnels vulnerable to deformations and structural damage caused by adjacent foundation pit construction.Such deformations-manifesting as horizontal displacement,h...The ongoing operation of subway systems makes existing tunnels vulnerable to deformations and structural damage caused by adjacent foundation pit construction.Such deformations-manifesting as horizontal displacement,heightened lateral convergence,and internal force redistribution-may significantly compromise subway operational safety.Grouting remediation has become a widely adopted solution for tunnel deformation control and structural reinforcement.Developing optimized grouting materials is crucial for improving remediation effectiveness,ensuring structural integrity,and maintaining uninterrupted subway operations.This investigation explores the substitution of fine mortar aggregates with 0.1 mm discarded rubber particles at varying concentrations(0%,3%,6%,9%,12%,and 15%).Experimental parameters included three water-cement ratios(0.65,0.70,and 0.75)with constant 4%WPU content.Mechanical properties including compressive strength,flexural strength,and compression-to-bending ratio were evaluated across specified curing periods.Material characterization employed Fourier Transform Infrared Spectroscopy(FTIR)spectroscopy for molecular analysis and Scanning Electron Microscopy(SEM)for microstructural examination.Results indicate optimal toughness at 0.70 water-cement ratio with 6%rubber content,meeting mechanical pumping specifications while maintaining structural performance.展开更多
Grouting is a widely applied technique for reinforcing fractured zones in deep soft rock tunnels.By infiltrating rock fissures,slurry materials enhance structural integrity and improve the overall stability of the sur...Grouting is a widely applied technique for reinforcing fractured zones in deep soft rock tunnels.By infiltrating rock fissures,slurry materials enhance structural integrity and improve the overall stability of the surrounding rock.The performance of grouting is primarily governed by the flow behavior and diffusion extent of the slurry.This review considers recent advances in the theory and methodology of slurry flow and diffusion in fractured rock.It examines commonly used grout materials,including cement-based,chemical,and composite formulations,each offering distinct advantages for specific geological conditions.Themechanisms of reinforcement vary significantly across materials,requiring tailored application strategies.The rheological properties of grouting slurries,particularly cement-based types,have been widely modeled using classical constitutive approaches.However,the influence of time-and space-dependent viscosity evolution on slurry behavior remains underexplored.Experimental studies have provided valuable insights into slurry diffusion,yet further research is needed to capture real-time behavior under multi-scale and multi-physics coupling conditions.Similarly,current numerical simulations are largely limited to twoand three-dimensional models of single-fracture flow.These models often neglect the complexity of fracture networks and geological heterogeneity,highlighting a need for more realistic and integrated simulation frameworks.Future research should focus on:(1)fine-scale modeling of slurry hydration and mechanical reinforcement processes;(2)cross-scale analysis of slurry flow under coupled thermal,hydraulic,andmechanical fields;and(3)development of realtime,three-dimensional dynamic simulation tools to capture the full grouting process.These efforts will strengthen the theoretical foundation and practical effectiveness of grouting in complex underground environments.展开更多
Grouting represents a reliable method for strengthening fractured rock masses and preventing seawater infiltration in subsea tunnel engineering. However, grouting composites are continuously subjected to harsh marine ...Grouting represents a reliable method for strengthening fractured rock masses and preventing seawater infiltration in subsea tunnel engineering. However, grouting composites are continuously subjected to harsh marine environments,experiencing both chemical and physical effects from high-concentration erosive seawater ions, elevated water pressure, and complex flow fields. This multi-factor erosion deterioration diminishes the waterproofing capabilities of grouting composites and threatens the service life of subsea tunnel linings. To investigate the erosion deteriortion mechanism induced by sulfate, erosion weakening experiments were conducted using a seawater flow simulation device. The research examined the compressive strength and permeability coefficient of grouting composites under different erosion durations, water-cement ratios, and grouting pressures. In the later stages of the experiment, the strength of grouting composites in the static water erosion control group(SEG) and dynamic water erosion group(DEG) decreased by 31.2% and 18.8%, respectively, compared to the freshwater control group(FG). Futhermore, the permeability coefficient exhibited significant increases. Subsequent microscopic analyses of the eroded grouting composites were performed. This research elucidated the erosion-weakening mechanism of grouting composites subjected to sulfate-induced degradation in complex marine environments. The study emphasizes the critical role of erosion resistance and durability in design and implementation. From practical perspective, this work establishes a foundation for developing enhanced strategies to improve the long-term performance and integrity of grouting composites in subsea tunnel applications.展开更多
Groundwater inrush is a hazard that always occurs during underground mining.Grouting is one of the most effective processes to seal underground water inflow for hazard prevention.In this study,grouting experiments are...Groundwater inrush is a hazard that always occurs during underground mining.Grouting is one of the most effective processes to seal underground water inflow for hazard prevention.In this study,grouting experiments are conducted by using a visualized transparent single-fracture replica with plane roughness.Image processing and analysis are performed to investigate the thermo–hydro–mechanical coupling effect on the grouting diffusion under coal mine flowing water conditions.The results show that higher ambient temperature leads to shorter initial gel time of chemical grout and leads to a better relative sealing efficiency in the case of a lower flow rate.However,with a higher water flow rate,the relative sealing efficiency is gradually reduced under higher temperature conditions.The grouting pressure,the seepage pressure,and the temperature are measured.The results reveal that the seepage pressure shows a positive correlation with the grouting pressure,while the temperature change shows a negative correlation with the seepage pressure and the grouting pressure.The“equivalent grouting point offset”effect of grouting shows an eccentric elliptical diffusion with larger grouting distance and width under lower temperature conditions.展开更多
As the cost of grouting treatment for water control in coal roofs during underground coal mining continues to rise,coupled with the accumulation of industrial solid waste resulting from rapid economic development in C...As the cost of grouting treatment for water control in coal roofs during underground coal mining continues to rise,coupled with the accumulation of industrial solid waste resulting from rapid economic development in China,the ecological environment is facing severe challenges.To address these issues,this study,based on a high water-to-cement ratio,uses mine overburden(OB)and furnace bottom ash(FBA)as the primary raw materials,with sodium silicate as the modifier,to develop a new type of geopolymer grouting material with high stability and compressive strength for coal roof water control.Additionally,COMSOL software was used to numerically simulate the diffusion process of the grout slurry in fractures under dynamic water flow.The results indicate that,with a sodium silicate modulus of 1.5 and a dosage of 4%,the stability of the slurry increased by 26.2%,and the 28-day compressive strength improved by 130.98%.Numerical simulations further show that the diffusion process of the slurry is closely related to slurry viscosity,grouting pressure,and grouting time and that the diffusion pattern in the fractures is similar to that of ultra-fine cement slurry.This study provides a theoretical basis for coal mine roof grouting water control projects.展开更多
Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinf...Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinforcing steel and affects the strength of the structure.The repair method is one approach to overcome this problem.This research aims to determine the effect of grouting and jacketing repairs on corroded concrete.The concrete used has dimensions of 15 cm×15 cm×60 cm with planned corrosion variations of 50%,60%,and 70%.The test objects were tested using the Non-Destructive Testing(NDT)method using Ultrasonic Pulse Velocity(UPV).The test results show that the average speed of normal concrete is 5070 m/s,while the lowest average speed is 3070 m/s on the 70%planned corrosion test object.The test object was then given a load of 1600 kgf.At this stage,there is a decrease in speed and wave shape with the lowest average speed obtained at 2753 m/s.The repair method is an effort to restore concrete performance by using grouting and jacketing.Grouting is done by injecting mortar material into it.Jacketing involves adding thickness to the existing concrete layer with additional layers of concrete.After improvements were made,there was an improvement in the UPV test,with a peak speed value of 4910 m/s.Repairing concrete by filling cracks can improve concrete continuity and reduce waveform distortion,thereby increasing wave propagation speed.展开更多
Compaction grouting is primarily applied based on empiricism,and it is challenging to quantify its densification effect.To address this issue,five sets of laboratory model tests on ideal compaction grouting were condu...Compaction grouting is primarily applied based on empiricism,and it is challenging to quantify its densification effect.To address this issue,five sets of laboratory model tests on ideal compaction grouting were conducted,with varying pressures from 400 kPa to 800 kPa,to quantitatively evaluate the densification effect in unsaturated soils.The response of surrounding soil during compaction grouting was monitored.The changes in dry density and void ratio induced by compaction grouting were obtained by monitoring volumetric water content to determine compaction efficiency.In addition,a model was developed and validated to predict the effective compaction range.The results show that soil dry density increased rapidly during compaction grouting before being stabilized at a consistent level.As expected,it is positively correlated with grouting pressures(GPs)and negatively correlated with the distance from the injection point.At higher GPs,the difference in densification effect around the injection point after compaction grouting was significant.Interestingly,variations in ultimate dry density and peak earth pressures perpendicular to the injection direction exhibited axisymmetric behavior around the injection point when comparing the dry density and earth pressure results.Furthermore,soil densification resulted in a decrease in suction.However,no significant effect of GP on suction at different soil positions was observed.Moreover,compaction efficiency decreased with increasing distance from the injection point,showing a strong linear relationship.In addition,the model results for the effective compaction range were basically consistent with the extrapolated values from the experimental results.展开更多
The rapid development of urban rail transit has posed increasing construction and operational challenges for metro tunnels,often leading to structural damage.Grouting technology using cement-based materials is widely ...The rapid development of urban rail transit has posed increasing construction and operational challenges for metro tunnels,often leading to structural damage.Grouting technology using cement-based materials is widely applied to address issues such as seepage,leakage,and alignment correction in shield tunnels.This study investigates the additional stress induced by grouting in silty soil layers,using cement-based grouts with different water-to-cement ratios and polyurethane-modified cement-based materials.Results show that additional stress decreases with depth and is more influenced by horizontal distance from the grouting point.In staged grouting,the first injection phase contributes about 50%of the peak additional stress.A lower water-to-cement ratio(e.g.,0.6)increases additional stress but reduces grout flowability,while a higher ratio improves diffusion but increases the risk of grout loss.(≥1.0)The polyurethane-modified cement-based material enhances stress transfer performance,increasing peak additional stress by approximately 10%.These findings provide theoretical guidance for optimizing material selection and grouting design in metro tunnel repair within silty soil layers.展开更多
Cement-based composite grouting materials were used to construct grouting cutoff wall for heavy metal contaminated soil in non-ferrous metal mining areas. Cement, fly ash, and slag as principal ingredients were mixed ...Cement-based composite grouting materials were used to construct grouting cutoff wall for heavy metal contaminated soil in non-ferrous metal mining areas. Cement, fly ash, and slag as principal ingredients were mixed with water glass in different ways to produce three composite grouting materials. In order to investigate the effect of water glass mixing ratio, Baume degree, fly ash and slag contents on the mechanical properties of the composite grouting materials, particularly their gel time and compressive strength, the beaker-to-beaker method of gel time test and unconfined compressive strength test were conducted. In addition, the phase composition and microstructure of the composite grouting materials were analyzed by the X-ray diffraction（XRD） and scanning electron microscope（SEM） techniques. The test results show that their gel time increases when water glass mixing ratio and Baume degree increase. The gel time increases dramatically when fly ash is added, but decreases slightly if fly ash is partly replaced by slag. When the mixing ratio of water glass is below 20%, their compressive strength increases with the increases of the ratio; when the ratio is above 20%, it significantly decreases. The compressive strength also tends to increase as Baume degree increases, and improves if fly ash and slag are added.展开更多
This paper discusses a new technique to improve soft ground with grouting piles and deep mixing piles. The bearing capacity of composite ground and the stress ratio between piles and soil is discussed by means of the ...This paper discusses a new technique to improve soft ground with grouting piles and deep mixing piles. The bearing capacity of composite ground and the stress ratio between piles and soil is discussed by means of the static test. Based on Mindlin solution and Boussinesq solution, the additional stress and settlement of the composite ground are acquired.Compared the practical value with calculation, a better calculating method is confirmed.展开更多
The chemical fluid property and the capillary structure of soil are important factors that affect grouting diffusion. Ignoring either factor will produce large errors in understanding the inherent laws of the diffusio...The chemical fluid property and the capillary structure of soil are important factors that affect grouting diffusion. Ignoring either factor will produce large errors in understanding the inherent laws of the diffusion process. Based on fractal geometry and the constitutive equation of Herschel-Bulkley fluid, an analytical model for Herschel-Bulkley fluid flowing in a porous geo-material with fractal characteristics is derived. The proposed model provides a theoretical basis for grouting design and helps to understand the chemical fluid flow in soil in real environments. The results indicate that the predictions from the proposed model show good consistency with the literature data and application results. Grouting pressure decreases with increasing diffusion distance. Under the condition that the chemical fluid flows the same distance, the grouting pressure undergoes almost no change at first and then decreases nonlinearly with increasing tortuosity dimension. With increasing rheological index, the pressure difference first decreases linearly, then presents a trend of nonlinear decrease, and then decreases linearly again. The pressure difference gradually increases with increasing viscosity and yield stress of the chemical fluid. The decreasing trend of the grouting pressure difference is non-linear and rapid for porosity Φ>0.4, while there is a linear and slow decrease in pressure difference for high porosity.展开更多
An inclined seven-story reinforced concrete building was leveled by a fracture grouting technique with quick-setting grout on a differential thickness of a clayey sand layer. The permeability and strength of clayey sa...An inclined seven-story reinforced concrete building was leveled by a fracture grouting technique with quick-setting grout on a differential thickness of a clayey sand layer. The permeability and strength of clayey sand were controlled by clay content, although sand was the primary component of the foundation soil. The elevations of the building columns at basement level were closely monitored to record both the heaved volume of mat foundation after grouting and the settled volume during pore pressure dissipation. During the stabilizing stage of grouting, the foundation soil was densified by the repetitive fracturing process, which resulted in the lateral movement of the foundation soil. When the grout is less able to push soil laterally than upwards, the building starts to lift, the so-called lifting stage of grouting. The grouting efficiency is influenced by soil type, soil stress history, and foundation pressure. A final grouting efficiency of 27% and a linear relationship between grout use and percentage of eleva-tion were obtained when this building was successfully and permanently leveled.展开更多
In order to study the influence of temperature on compressive strength of polymer grouting material,the compression specimen injection mold is self-made,and the uniaxial compressive test was carried out in the tempera...In order to study the influence of temperature on compressive strength of polymer grouting material,the compression specimen injection mold is self-made,and the uniaxial compressive test was carried out in the temperature control box under different temperatures.The change regularity of compressive strength of polymer grouting material under different temperatures and the law of volume changes of polymer samples were obtained.The experimental results show that：the compressive strength of polymer material increases with the increase of density;the temperature change has a certain influence on the compressive strength of polymer grouting material;the compressive strength decreases with temperature increases under the same density,but the compressive strength is not significantly affected by temperature when the density is less than 0.4 g/cm3;the volume change of the samples accords with the law of thermal expansion and contraction when temperature changes,and the increase of the volume is obvious when it is under high temperature.The achievements will provide an important basis to the application of the polymer grouting material.展开更多
There are quite a few studies that have been done on borehole sealing theory both domestically and internationally.The existing researches usually consider drilling of the surroundings as a dense homogeneous elastic b...There are quite a few studies that have been done on borehole sealing theory both domestically and internationally.The existing researches usually consider drilling of the surroundings as a dense homogeneous elastic body which does not meet the characteristics of real drilling of the fractured body.Based on the loosing-circle theory and analyses of the surrounding rock stress field,cracks and seepage fields,combined with Newtonian fluid spherical grouting model,we deduced the dynamic relationship between the seepage coefficient and rock or grouting parameters of the drilling sealing fluid mode of spherical fissure grouting.In this experiment,mucus was injected in the simulated coal seam and the permeability coefficient of the sealing body was calculated by using the model.To verify the validity of the model,the calculated sealing body number was compared with the extreme negative pressure that the sealing body could withstand.The theoretical model revealed the drilling sealing fluid mechanism,provided a method for the quantitative calculation of the drilling sealing fluid effect by grouting mode and a reference for the subsequent research of sealing mechanism.展开更多
A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone...A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone and lining are assumed as elastic-perfectly plastic and governed by the unified strength theory(UST). This new solution has made it possible to consider the interaction between seepage pressure, lining, grouting and rock mass, and the intermediate principal stress effect together. Moreover, parametric analysis is carried out to identify the influence of the related parameters on the plastic zone radius. Under the given conditions, the results show that the plastic zone radius decreases with an increasing cohesion, internal friction angle and hydraulic conductivity of lining and unified failure criterion parameter, respectively; whereas the plastic zone radius increases with the growth of elasticity modulus of lining. Comparison of results from the new solution and the other published one shows well agreement and provides confidence in the new solution proposed.展开更多
基金supported by the China Scholarship Council(CSC,Grant No.202108050072)JSPS KAKENHI(Grant No.JP19KK0121)。
文摘Grouting has been the most effective approach to mitigate water inrush disasters in underground engineering due to its ability to plug groundwater and enhance rock strength.Nevertheless,there is a lack of potent numerical tools for assessing the grouting effectiveness in water-rich fractured strata.In this study,the hydro-mechanical coupled discontinuous deformation analysis(HM-DDA)is inaugurally extended to simulate the grouting process in a water-rich discrete fracture network(DFN),including the slurry migration,fracture dilation,water plugging in a seepage field,and joint reinforcement after coagulation.To validate the capabilities of the developed method,several numerical examples are conducted incorporating the Newtonian fluid and Bingham slurry.The simulation results closely align with the analytical solutions.Additionally,a set of compression tests is conducted on the fresh and grouted rock specimens to verify the reinforcement method and calibrate the rational properties of reinforced joints.An engineering-scale model based on a real water inrush case of the Yonglian tunnel in a water-rich fractured zone has been established.The model demonstrates the effectiveness of grouting reinforcement in mitigating water inrush disaster.The results indicate that increased grouting pressure greatly affects the regulation of water outflow from the tunnel face and the prevention of rock detachment face after excavation.
基金Funded by a Science and Technology Project from the Ministry of Housing and Urban-Rural Development of the People’s Republic of China(No.2019-K-047)Yangzhou Government-Yangzhou University Cooperative Platform Project for Science and Technology Innovation(No.YZ2020262)。
文摘The chloride penetration resistance of cement-based grout materials was improved by nano-silica emulsion.Specimens of mixtures containing different nano-silica particles or emulsions were exposed in sodium chloride solutions of specific concentrations with different test ages.Hardened properties of the mixes were assessed in terms of weight loss and compressive strength.X-ray diffraction(XRD)and scanning electron microscopy(SEM)of mixes were performed to analysis the phase evolution and microstructure.The results demonstrated that the introduction of nano-SiO_(2) emulsion significantly decreased the compressive strength loss and calcium hydroxide(CH)crystal content of hydration production,and then enhanced the resistance of cement-based grouting materials to chloride ion penetration.This improvement derives from the filling and pozzolanic effects of nano-SiO_(2) particles,which were incorporated via an emulsion and attributed to a well dispersion in grouting matrix.
基金The Fundamental Research Funds for the Central Universities,Grant/Award Number:YJ2021148National Natural Science Foundation of China,Grant/Award Number:52374132。
文摘Appropriate determination of the mix ratios of cement grouts is of vital importance to the quality of rock grouting and the risk reduction of groundwater inflow.The behavior of grout,often highly temperature dependent,is likely to be affected by the elevated ground temperature in deep rock masses.This paper aims to experimentally gain insights into the effects of elevated ground temperatures on the properties of cement grout in fresh and hardened states in deep rock grouting.The results revealed that a temperature of 35°C is crucial for changes in the properties of thick cement grout with a water–cement ratio of less than 0.8.When the temperature is up to 35°C,there can be significant improvements in rheological parameters,acceleration of grout setting,and increase in the rheological time dependence of thick cement grout;however,there may also be a slight impact on the initial grout flowability and the nature of shear thinning.The high temperature may still improve the stability of fresh cement grout and also improve the porosity and creep deformation of hardened cement grout considerably.The proposed constitutive model that couples the Burgers model with a fractional derivativebased Abel dashpot in the series can be used to characterize the creep behavior of hardened cement grout appropriately.The paper provides a valuable reference for optimization of mixture design of cement grouts,thus enhancing deep rock grouting quality and improving safety.
基金supported by the National Natural Science Foundation of China(Grant No.U23A6018)Science and Technology Program of Hebei(Grant No.E2022202041,2022HBQZYCXY004,242Q9920Z)the project of“Key technologies of seepage control system for large-scale hydraulic projects”was also gratefully appreciated.
文摘Curtain grouting projects are characterized by their large scale and complexity,presenting significant challenges for real-time prediction of grout penetration using traditional methods.This study introduces an intelligent prediction method for grouting in fractured rock masses based on three core principles:integration of multi-source input features,fracture voxel modeling,and shortest path in sequential grouting.Three categories of data(geological structure data,grouting environmental data,and grouting operation data in the concept of a grouting geological model)are integrated and served as multi-source structured data in the intelligent prediction of grouting.A voxelization model quantifies the spatial characteristics of fractures,with voxel size optimized for capturing grouting paths.A shortest path algorithm based on a hierarchical solution is then developed to calculate grout penetration distances in the process of sequential grouting.A complete analysis framework is established,from the voxelization of the fracture network model to precise voxel classification,ultimately achieving an accurate prediction of grout penetration.The method demonstrates excellent performance on the test set,with validation against numerical methods in single-fracture and sequential grouting scenarios confirming its accuracy and prediction efficiency as hundreds of times faster than numerical methods.Application to the Dongzhuang hydraulic project’s grouting test area further validates its effectiveness in multi-hole grouting scenarios.
基金the funding support from the Natural Science Foundation of China(Grant No.52130402)the Anhui Province Graduate Education Quality Engineering Project(Grant No.2023cxcysj088)the China Scholarship Council Grants Program(Grant No.202308340082).
文摘Grouting injection is a vital technique for addressing the challenges of high stress and significant deformation in the surrounding rock during deep mining operations,playing a crucial role in promoting green and low-carbon extraction methodologies.In this study,grouting reinforcement processes were examined by conducting grouting experiments on a fractured rock with varying negative pressures(0-100 kPa),followed by uniaxial compression testing of the grout-reinforced bodies.This investigation explored the diffusion patterns of grout under negative pressure and established a constitutive model of damage-bearing capacity for bodies reinforced by negative pressure grouting.It further studied the enhancement effect of negative pressure on the load-bearing capacity of the reinforced bodies and analyzed the instability mechanism of damage and failure in these bodies.The results indicated that the diffusion of grout under negative pressure is influenced by four types of forces,which alter the extent of grout diffusion within the fractured rock mass.Introducing a damage constitutive model that serially connects pore and framework elements characterizes the damage and failure behavior of groutreinforced bodies under different negative pressures.As the negative pressure increases,changes in porosity,water-to-cement ratio,and admixture quantity occur in the grout-reinforced specimens,with the strength mean curve showing a trend of first increasing and then decreasing,reaching a threshold at a negative pressure of 60 kPa.With increasing negative pressure,the negative pressure damage variable decreases and then increases,and the stronger the interfacial microelement connections caused by the negative pressure,the greater the bearing capacity,ultimately manifesting in different failure modes.
基金supported by the National Natural Science Foundation of China,Grant Nos.42477185,41602308the Zhejiang Provincial Natural Science Foundation of China,Grant No.LY20E080005+2 种基金the Zhejiang Province University Students Science and Technology Innovation Program,Grant No.0201310P28the PostGraduate Course Construction Project of Zhejiang University of Science and Technology,Grant No.2021yjskj05the Zhejiang University of Science and Technology Graduate Research and Innovation Fund,Grant No.2023yjskc10.
文摘The ongoing operation of subway systems makes existing tunnels vulnerable to deformations and structural damage caused by adjacent foundation pit construction.Such deformations-manifesting as horizontal displacement,heightened lateral convergence,and internal force redistribution-may significantly compromise subway operational safety.Grouting remediation has become a widely adopted solution for tunnel deformation control and structural reinforcement.Developing optimized grouting materials is crucial for improving remediation effectiveness,ensuring structural integrity,and maintaining uninterrupted subway operations.This investigation explores the substitution of fine mortar aggregates with 0.1 mm discarded rubber particles at varying concentrations(0%,3%,6%,9%,12%,and 15%).Experimental parameters included three water-cement ratios(0.65,0.70,and 0.75)with constant 4%WPU content.Mechanical properties including compressive strength,flexural strength,and compression-to-bending ratio were evaluated across specified curing periods.Material characterization employed Fourier Transform Infrared Spectroscopy(FTIR)spectroscopy for molecular analysis and Scanning Electron Microscopy(SEM)for microstructural examination.Results indicate optimal toughness at 0.70 water-cement ratio with 6%rubber content,meeting mechanical pumping specifications while maintaining structural performance.
基金funded by the National Natural Science Foundation of China[U22A20234]Hubei Province key research and development project[2023BCB121]Wuhan innovation supporting projects[2023020201010079].
文摘Grouting is a widely applied technique for reinforcing fractured zones in deep soft rock tunnels.By infiltrating rock fissures,slurry materials enhance structural integrity and improve the overall stability of the surrounding rock.The performance of grouting is primarily governed by the flow behavior and diffusion extent of the slurry.This review considers recent advances in the theory and methodology of slurry flow and diffusion in fractured rock.It examines commonly used grout materials,including cement-based,chemical,and composite formulations,each offering distinct advantages for specific geological conditions.Themechanisms of reinforcement vary significantly across materials,requiring tailored application strategies.The rheological properties of grouting slurries,particularly cement-based types,have been widely modeled using classical constitutive approaches.However,the influence of time-and space-dependent viscosity evolution on slurry behavior remains underexplored.Experimental studies have provided valuable insights into slurry diffusion,yet further research is needed to capture real-time behavior under multi-scale and multi-physics coupling conditions.Similarly,current numerical simulations are largely limited to twoand three-dimensional models of single-fracture flow.These models often neglect the complexity of fracture networks and geological heterogeneity,highlighting a need for more realistic and integrated simulation frameworks.Future research should focus on:(1)fine-scale modeling of slurry hydration and mechanical reinforcement processes;(2)cross-scale analysis of slurry flow under coupled thermal,hydraulic,andmechanical fields;and(3)development of realtime,three-dimensional dynamic simulation tools to capture the full grouting process.These efforts will strengthen the theoretical foundation and practical effectiveness of grouting in complex underground environments.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 42477194 and 52279115)Fundamental Research Funds for the Central Universities (Grant No. 202441008)。
文摘Grouting represents a reliable method for strengthening fractured rock masses and preventing seawater infiltration in subsea tunnel engineering. However, grouting composites are continuously subjected to harsh marine environments,experiencing both chemical and physical effects from high-concentration erosive seawater ions, elevated water pressure, and complex flow fields. This multi-factor erosion deterioration diminishes the waterproofing capabilities of grouting composites and threatens the service life of subsea tunnel linings. To investigate the erosion deteriortion mechanism induced by sulfate, erosion weakening experiments were conducted using a seawater flow simulation device. The research examined the compressive strength and permeability coefficient of grouting composites under different erosion durations, water-cement ratios, and grouting pressures. In the later stages of the experiment, the strength of grouting composites in the static water erosion control group(SEG) and dynamic water erosion group(DEG) decreased by 31.2% and 18.8%, respectively, compared to the freshwater control group(FG). Futhermore, the permeability coefficient exhibited significant increases. Subsequent microscopic analyses of the eroded grouting composites were performed. This research elucidated the erosion-weakening mechanism of grouting composites subjected to sulfate-induced degradation in complex marine environments. The study emphasizes the critical role of erosion resistance and durability in design and implementation. From practical perspective, this work establishes a foundation for developing enhanced strategies to improve the long-term performance and integrity of grouting composites in subsea tunnel applications.
基金National Natural Science Foundation of China,Grant/Award Number:41902292。
文摘Groundwater inrush is a hazard that always occurs during underground mining.Grouting is one of the most effective processes to seal underground water inflow for hazard prevention.In this study,grouting experiments are conducted by using a visualized transparent single-fracture replica with plane roughness.Image processing and analysis are performed to investigate the thermo–hydro–mechanical coupling effect on the grouting diffusion under coal mine flowing water conditions.The results show that higher ambient temperature leads to shorter initial gel time of chemical grout and leads to a better relative sealing efficiency in the case of a lower flow rate.However,with a higher water flow rate,the relative sealing efficiency is gradually reduced under higher temperature conditions.The grouting pressure,the seepage pressure,and the temperature are measured.The results reveal that the seepage pressure shows a positive correlation with the grouting pressure,while the temperature change shows a negative correlation with the seepage pressure and the grouting pressure.The“equivalent grouting point offset”effect of grouting shows an eccentric elliptical diffusion with larger grouting distance and width under lower temperature conditions.
文摘As the cost of grouting treatment for water control in coal roofs during underground coal mining continues to rise,coupled with the accumulation of industrial solid waste resulting from rapid economic development in China,the ecological environment is facing severe challenges.To address these issues,this study,based on a high water-to-cement ratio,uses mine overburden(OB)and furnace bottom ash(FBA)as the primary raw materials,with sodium silicate as the modifier,to develop a new type of geopolymer grouting material with high stability and compressive strength for coal roof water control.Additionally,COMSOL software was used to numerically simulate the diffusion process of the grout slurry in fractures under dynamic water flow.The results indicate that,with a sodium silicate modulus of 1.5 and a dosage of 4%,the stability of the slurry increased by 26.2%,and the 28-day compressive strength improved by 130.98%.Numerical simulations further show that the diffusion process of the slurry is closely related to slurry viscosity,grouting pressure,and grouting time and that the diffusion pattern in the fractures is similar to that of ultra-fine cement slurry.This study provides a theoretical basis for coal mine roof grouting water control projects.
基金supported by the Ministry of Education,Culture,Research,and Technology(Indonesia),Grant number 107/E5/PG.02.00.PL/2024,AZ.
文摘Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinforcing steel and affects the strength of the structure.The repair method is one approach to overcome this problem.This research aims to determine the effect of grouting and jacketing repairs on corroded concrete.The concrete used has dimensions of 15 cm×15 cm×60 cm with planned corrosion variations of 50%,60%,and 70%.The test objects were tested using the Non-Destructive Testing(NDT)method using Ultrasonic Pulse Velocity(UPV).The test results show that the average speed of normal concrete is 5070 m/s,while the lowest average speed is 3070 m/s on the 70%planned corrosion test object.The test object was then given a load of 1600 kgf.At this stage,there is a decrease in speed and wave shape with the lowest average speed obtained at 2753 m/s.The repair method is an effort to restore concrete performance by using grouting and jacketing.Grouting is done by injecting mortar material into it.Jacketing involves adding thickness to the existing concrete layer with additional layers of concrete.After improvements were made,there was an improvement in the UPV test,with a peak speed value of 4910 m/s.Repairing concrete by filling cracks can improve concrete continuity and reduce waveform distortion,thereby increasing wave propagation speed.
基金the National Natural Science Foundation of China(Grant Nos.42172298,42002289)the Shanghai Geological Star Program for their financial support.
文摘Compaction grouting is primarily applied based on empiricism,and it is challenging to quantify its densification effect.To address this issue,five sets of laboratory model tests on ideal compaction grouting were conducted,with varying pressures from 400 kPa to 800 kPa,to quantitatively evaluate the densification effect in unsaturated soils.The response of surrounding soil during compaction grouting was monitored.The changes in dry density and void ratio induced by compaction grouting were obtained by monitoring volumetric water content to determine compaction efficiency.In addition,a model was developed and validated to predict the effective compaction range.The results show that soil dry density increased rapidly during compaction grouting before being stabilized at a consistent level.As expected,it is positively correlated with grouting pressures(GPs)and negatively correlated with the distance from the injection point.At higher GPs,the difference in densification effect around the injection point after compaction grouting was significant.Interestingly,variations in ultimate dry density and peak earth pressures perpendicular to the injection direction exhibited axisymmetric behavior around the injection point when comparing the dry density and earth pressure results.Furthermore,soil densification resulted in a decrease in suction.However,no significant effect of GP on suction at different soil positions was observed.Moreover,compaction efficiency decreased with increasing distance from the injection point,showing a strong linear relationship.In addition,the model results for the effective compaction range were basically consistent with the extrapolated values from the experimental results.
基金supported by the National Natural Science Foundation of China(No.42477185)Natural Science Foundation of Zhejiang Province(LQ24A020015)+1 种基金Research Achievement Award Cultivation Project of Zhejiang University of Science and Technology(2023JLYB001)the Postgraduate Course Construction Project of Zhejiang University of Science and Technology(2024yjskj05).
文摘The rapid development of urban rail transit has posed increasing construction and operational challenges for metro tunnels,often leading to structural damage.Grouting technology using cement-based materials is widely applied to address issues such as seepage,leakage,and alignment correction in shield tunnels.This study investigates the additional stress induced by grouting in silty soil layers,using cement-based grouts with different water-to-cement ratios and polyurethane-modified cement-based materials.Results show that additional stress decreases with depth and is more influenced by horizontal distance from the grouting point.In staged grouting,the first injection phase contributes about 50%of the peak additional stress.A lower water-to-cement ratio(e.g.,0.6)increases additional stress but reduces grout flowability,while a higher ratio improves diffusion but increases the risk of grout loss.(≥1.0)The polyurethane-modified cement-based material enhances stress transfer performance,increasing peak additional stress by approximately 10%.These findings provide theoretical guidance for optimizing material selection and grouting design in metro tunnel repair within silty soil layers.
基金Projects(41472278,41202220)supported by the National Natural Science Foundation of ChinaProject(20120022120003)supported by the Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(51900265647)supported by the Beijing Higher Education Young Elite Teacher Project,ChinaProject(2652012065)supported by the Fundamental Research Funds for the Central Universities,China
文摘Cement-based composite grouting materials were used to construct grouting cutoff wall for heavy metal contaminated soil in non-ferrous metal mining areas. Cement, fly ash, and slag as principal ingredients were mixed with water glass in different ways to produce three composite grouting materials. In order to investigate the effect of water glass mixing ratio, Baume degree, fly ash and slag contents on the mechanical properties of the composite grouting materials, particularly their gel time and compressive strength, the beaker-to-beaker method of gel time test and unconfined compressive strength test were conducted. In addition, the phase composition and microstructure of the composite grouting materials were analyzed by the X-ray diffraction（XRD） and scanning electron microscope（SEM） techniques. The test results show that their gel time increases when water glass mixing ratio and Baume degree increase. The gel time increases dramatically when fly ash is added, but decreases slightly if fly ash is partly replaced by slag. When the mixing ratio of water glass is below 20%, their compressive strength increases with the increases of the ratio; when the ratio is above 20%, it significantly decreases. The compressive strength also tends to increase as Baume degree increases, and improves if fly ash and slag are added.
文摘This paper discusses a new technique to improve soft ground with grouting piles and deep mixing piles. The bearing capacity of composite ground and the stress ratio between piles and soil is discussed by means of the static test. Based on Mindlin solution and Boussinesq solution, the additional stress and settlement of the composite ground are acquired.Compared the practical value with calculation, a better calculating method is confirmed.
基金Project(2015CB060200)supported by the National Basic Research Program of ChinaProject supported by the R-D Program of Gangxi Province of ChinaProject(201622ts093)supported by the Fundamental Research Funds for the Central Universities,China
文摘The chemical fluid property and the capillary structure of soil are important factors that affect grouting diffusion. Ignoring either factor will produce large errors in understanding the inherent laws of the diffusion process. Based on fractal geometry and the constitutive equation of Herschel-Bulkley fluid, an analytical model for Herschel-Bulkley fluid flowing in a porous geo-material with fractal characteristics is derived. The proposed model provides a theoretical basis for grouting design and helps to understand the chemical fluid flow in soil in real environments. The results indicate that the predictions from the proposed model show good consistency with the literature data and application results. Grouting pressure decreases with increasing diffusion distance. Under the condition that the chemical fluid flows the same distance, the grouting pressure undergoes almost no change at first and then decreases nonlinearly with increasing tortuosity dimension. With increasing rheological index, the pressure difference first decreases linearly, then presents a trend of nonlinear decrease, and then decreases linearly again. The pressure difference gradually increases with increasing viscosity and yield stress of the chemical fluid. The decreasing trend of the grouting pressure difference is non-linear and rapid for porosity Φ>0.4, while there is a linear and slow decrease in pressure difference for high porosity.
基金Project supported by the Taisei Corporation of Taiwan Office
文摘An inclined seven-story reinforced concrete building was leveled by a fracture grouting technique with quick-setting grout on a differential thickness of a clayey sand layer. The permeability and strength of clayey sand were controlled by clay content, although sand was the primary component of the foundation soil. The elevations of the building columns at basement level were closely monitored to record both the heaved volume of mat foundation after grouting and the settled volume during pore pressure dissipation. During the stabilizing stage of grouting, the foundation soil was densified by the repetitive fracturing process, which resulted in the lateral movement of the foundation soil. When the grout is less able to push soil laterally than upwards, the building starts to lift, the so-called lifting stage of grouting. The grouting efficiency is influenced by soil type, soil stress history, and foundation pressure. A final grouting efficiency of 27% and a linear relationship between grout use and percentage of eleva-tion were obtained when this building was successfully and permanently leveled.
文摘In order to study the influence of temperature on compressive strength of polymer grouting material,the compression specimen injection mold is self-made,and the uniaxial compressive test was carried out in the temperature control box under different temperatures.The change regularity of compressive strength of polymer grouting material under different temperatures and the law of volume changes of polymer samples were obtained.The experimental results show that：the compressive strength of polymer material increases with the increase of density;the temperature change has a certain influence on the compressive strength of polymer grouting material;the compressive strength decreases with temperature increases under the same density,but the compressive strength is not significantly affected by temperature when the density is less than 0.4 g/cm3;the volume change of the samples accords with the law of thermal expansion and contraction when temperature changes,and the increase of the volume is obvious when it is under high temperature.The achievements will provide an important basis to the application of the polymer grouting material.
基金supports provided by the State Key Basic Research Program of China(No.2011CB201205)the National Natural Science Foundation of China(No.51074161)+1 种基金the independent research of the State Key Laboratory of Coal Resources & Mine Safety(No.SKLCRSM08X03)the Youth Science and Technology Fund of China University of Mining and Technology(No.JGY101605)
文摘There are quite a few studies that have been done on borehole sealing theory both domestically and internationally.The existing researches usually consider drilling of the surroundings as a dense homogeneous elastic body which does not meet the characteristics of real drilling of the fractured body.Based on the loosing-circle theory and analyses of the surrounding rock stress field,cracks and seepage fields,combined with Newtonian fluid spherical grouting model,we deduced the dynamic relationship between the seepage coefficient and rock or grouting parameters of the drilling sealing fluid mode of spherical fissure grouting.In this experiment,mucus was injected in the simulated coal seam and the permeability coefficient of the sealing body was calculated by using the model.To verify the validity of the model,the calculated sealing body number was compared with the extreme negative pressure that the sealing body could withstand.The theoretical model revealed the drilling sealing fluid mechanism,provided a method for the quantitative calculation of the drilling sealing fluid effect by grouting mode and a reference for the subsequent research of sealing mechanism.
基金Project(51378309)supported by National Natural Science Foundation of China
文摘A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone and lining are assumed as elastic-perfectly plastic and governed by the unified strength theory(UST). This new solution has made it possible to consider the interaction between seepage pressure, lining, grouting and rock mass, and the intermediate principal stress effect together. Moreover, parametric analysis is carried out to identify the influence of the related parameters on the plastic zone radius. Under the given conditions, the results show that the plastic zone radius decreases with an increasing cohesion, internal friction angle and hydraulic conductivity of lining and unified failure criterion parameter, respectively; whereas the plastic zone radius increases with the growth of elasticity modulus of lining. Comparison of results from the new solution and the other published one shows well agreement and provides confidence in the new solution proposed.
