Previous studies have demonstrated that the surge in jacking force during the Guanjingkou project is caused by the contact conditions of the debris bentonite slurry outside the pipe.Therefore,this paper further system...Previous studies have demonstrated that the surge in jacking force during the Guanjingkou project is caused by the contact conditions of the debris bentonite slurry outside the pipe.Therefore,this paper further systematically investigates the influence of different debris slurry mass ratios(SLRs)and different particle size distributions(PSDs)on the pipe-rock friction characteristics using friction tests.The test results reveal that under the same PSD,an adequate amount of slurry(with an SLR of 1:4)consistently yields the lowest friction coefficient.When the SLR is between 1:2 and 1:3,the viscosity of the slurry reaches its peak,resulting in the highest friction coefficient.Additionally,when the PSD is 1:1:5 and 1:1:15,the friction coefficient is primarily governed by the plowing effect at the contact surface.When the PSD is 5:1:1 and 15:1:1,the friction coefficient is mainly controlled by the void ratio(VR)of debris.In the case of PSDs 1:5:1 and 1:15:1,the friction coefficient is jointly controlled by the adhesion effect of high-viscosity slurry and the plowing effect at the contact surface,and it gradually shifts towards being dominated by the VR as the amount of debris increases.Regardless of the SLRs and PSDs,the continuous deposition of debris and the injection of slurry incessantly exacerbate both the plowing and adhesion effects,creating a vicious cycle.This is the reason why the high-pressure water flushing method can not only fail to resolve the issue but also accelerate the occurrence of the surge in jacking force.展开更多
A steel underground pipeline with a diameter of 2.4 m and a total length of 3,617 m(plate thickness of 26 mm)has been constructed in a city in central Hubei,and the engineering,procurement,and construction(EPC)project...A steel underground pipeline with a diameter of 2.4 m and a total length of 3,617 m(plate thickness of 26 mm)has been constructed in a city in central Hubei,and the engineering,procurement,and construction(EPC)project has been lifted from the upstream channel to supplement water to the downstream lake inside the city.Through preliminary geological survey data,site topographic and geomorphic survey,urban construction,as well as the requirements of the construction party,the preliminary arrangement of working wells and receiving wells as well as the selection and customization of pipe jacking machines have been proposed.Frequency conversion motor and remote monitoring technology are adopted for geotechnical change and long-distance pipe jacking.Through detailed survey,the rock and soil change section as well as gradual change conditions have been determined,the accuracy of construction mechanics calculation and construction operation control have improved,the basis and analysis basis are provided,and some experiences in construction operation are summarized.展开更多
The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The re...The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The rectangular pipe jacking machine occupies a small area during the initial excavation. It is suitable for shallow soil covering and short-distance excavation. It is more economical and applicable than shield machine and has high construction efficiency. During the construction process, technical measures such as attitude measurement and adjustment of pipe jacking machine, surrounding rock grouting and friction reduction can effectively ensure the smooth construction of pipe jacking machine, and provide reference for large section pipe jacking machine in shallow soil construction.展开更多
By using site observation data and establishing 3D model using ANSYS software, this paper has discussed the strain change of stratum stress during process of jacking-in and the impact of machine head on ground surface...By using site observation data and establishing 3D model using ANSYS software, this paper has discussed the strain change of stratum stress during process of jacking-in and the impact of machine head on ground surface under different frontal resistances. Analysis of the two cases shows that soil pressure reaches its maximum point when the soil is right above machine head, and soil stress will gradually decline when machine head passes over it. It also shows that impact brought by pipe-jacking construction on stress change of the surrounding soil is limited. The thesis suggest that road surface should be consolidated and soil condition be improved before construction to prevent loss and disaster caused by road surface deformation, jacking force can be increased so that jacking efficiency can be enhanced when ground stratum is well filled with soil, but the frontal resistance facing machine head should be equal to surrounding soil pressure in order to avoid rise of ground surface.展开更多
In Japan when urban infrastructures need to be constructed, the difficulty of utilizing the ground or shallow strata will lead to a more frequent use of the deep strata. The common construction methods are open-cut, p...In Japan when urban infrastructures need to be constructed, the difficulty of utilizing the ground or shallow strata will lead to a more frequent use of the deep strata. The common construction methods are open-cut, pipe jacking, and shield methods. In recent years, a new pipe jacking method has been established that can be adapted to 20 m below the ground or more. Using this method, the drivage machine and the jacking pipe continue to move an underground until the completion of the driving. Therefore an over-cutting area (so-called tail-void) must be formed to lower the friction between the ground and the pipe. The tail-void is filled with lubrications. However, because the stress release from the ground continues to advance when the tail-void is formed, hence there are some challenges required to cope with the stability of the surrounding ground. In order to utilize the pipe jacking method in the deeper strata layers, the theory, analysis and installation of tail-void have to be systemized, and such systematic data must be stored. Therefore, the conditions of tail-void in the deep pipe jacking method are discussed using numerical analyses.展开更多
Tunnels in an urban area, in many cases, are constructed in soft ground which contains underground water, near existing facilities and structures. Structural stability for the tunnel and also the nearby structures and...Tunnels in an urban area, in many cases, are constructed in soft ground which contains underground water, near existing facilities and structures. Structural stability for the tunnel and also the nearby structures and facilities is vital in this kind of work. Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of underground pipelines of sewage systems. This method utilizes mud slurry that is formed around the pipes in order to stabilize the surrounding soil. In the pipe roof method the tubing elements that are constructed by slurry pipe jacking are near each other longitudinally, and create a rigid and stable lining before the excavation of the main tunnel. This paper discusses ＇the application of a slurry pipe jacking system on ＇the pipe roof method by means of numerical analysis. Because of the rigid behavior of the lining, the results show little subsidence, making this method a reliable method of constructing large tunnels with small cover in an urban area.展开更多
In the construction of municipal road drainage projects,pipe jacking construction is a relatively common construction method.This construction technology can avoid a large amount of excavation work,improve drainage co...In the construction of municipal road drainage projects,pipe jacking construction is a relatively common construction method.This construction technology can avoid a large amount of excavation work,improve drainage construction efficiency,avoid large-scale damage to the road surface,and exert small traffic impact.Therefore,it is currently widely used in drainage construction,but judging from the current actual application situation,there are still many problems that require further improvement.This article mainly analyzes the advantages of and current technical problems in pipe jacking construction technology in detail,explores corresponding solutions,and lays a foundation for the optimization of municipal road drainage engineering construction.展开更多
Traditional construction techniques have a significant impact on the environment and are associated with long construction durations in the construction of municipal rainwater pipelines.Pipe jacking technology,a new t...Traditional construction techniques have a significant impact on the environment and are associated with long construction durations in the construction of municipal rainwater pipelines.Pipe jacking technology,a new type of pipeline construction method,enables non-excavation construction and can address the shortcomings of traditional pipeline construction.This article analyzes the concept and application advantages of pipe jacking technology.Combining engineering examples,it explores the application strategies of pipe jacking technology in the construction process of municipal rainwater pipelines for reference.展开更多
In the municipal engineering construction, with the promotion of mechanized construction mode and the increasingly mature and perfect construction technical conditions, the pipe jacking construction gradually develops...In the municipal engineering construction, with the promotion of mechanized construction mode and the increasingly mature and perfect construction technical conditions, the pipe jacking construction gradually develops and progresses in the exploration of construction. In the municipal water supply and drainage construction, we should pay more attention to the application of pipe jacking technology, strictly implement various construction plans, improve the construction effect of water supply and drainage, and give full play to the application value and advantages of pipe jacking technology, which is beneficial to the healthy and stable development of municipal construction in China.展开更多
This paper provides a review of the history and development of pipe jacking and microtunneling methods with extensive referencing to the published literature.The application of such methods in comparison with other tr...This paper provides a review of the history and development of pipe jacking and microtunneling methods with extensive referencing to the published literature.The application of such methods in comparison with other trenchless technologies is discussed and the various planning,design and construction aspects are introduced.The emphasis of the paper is to trace the academic research and field monitoring results covering critical aspects of design and construction with a particular emphasis on jacking force estimation and the effect of lubrication on jacking forces.展开更多
Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation...Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.展开更多
1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in leng...1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced concrete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.展开更多
The moving trajectory of the pipe-jacking machine(PJM),which primarily determines the end quality of jacked tunnels,must be controlled strictly during the entire jacking process.Developing prediction models to support...The moving trajectory of the pipe-jacking machine(PJM),which primarily determines the end quality of jacked tunnels,must be controlled strictly during the entire jacking process.Developing prediction models to support drivers in performing rectifications in advance can effectively avoid considerable trajectory deviations from the designed jacking axis.Hence,a gated recurrent unit(GRU)-based deep learning framework is proposed herein to dynamically predict the moving trajectory of the PJM.In this framework,operational data are first extracted from a data acquisition system;subsequently,they are preprocessed and used to establish GRU-based multivariate multistep-ahead direct prediction models.To verify the performance of the proposed framework,a case study of a large pipe-jacking project in Shanghai and comparisons with other conventional models(i.e.,long short-term memory(LSTM)network and recurrent neural network(RNN))are conducted.In addition,the effects of the activation function and input time-step length on the prediction performance of the proposed framework are investigated and discussed.The results show that the proposed framework can dynamically and precisely predict the PJM moving trajectory during the pipe-jacking process,with a minimum mean absolute error and root mean squared error(RMSE)of 0.1904 and 0.5011 mm,respectively.The RMSE of the GRU-based models is lower than those of the LSTM-and RNN-based models by 21.46%and 46.40%at the maximum,respectively.The proposed framework is expected to provide an effective decision support for moving trajectory control and serve as a foundation for the application of deep learning in the automatic control of pipe jacking.展开更多
Previous studies on pipe friction resistance are mainly concentrated in the soil layer,whereas the study on that in the rock stratum is limited.To estimate the pipe friction resistance in the rock stratum,the calculat...Previous studies on pipe friction resistance are mainly concentrated in the soil layer,whereas the study on that in the rock stratum is limited.To estimate the pipe friction resistance in the rock stratum,the calculation models of pipe friction resistance and their applica-tion conditions were compared first.Then the friction resistance calculation model for pipe jacking in the rock stratum was established and simplified.Lastly,the measured(FM)and the computed(FN)pipe friction resistance was compared to validate the simplified friction resistance calculation model.The following conclusions can be drawn:(1)The existing calculation methods of pipe friction resistance can be well verified in the soil layer but cannot be applied in the rock stratum.(2)Sediment,pipe–rock friction coefficient and mud buoyancy are the main factors affecting the pipe friction resistance in long-distance rock pipe jacking engineering.(3)The simplified calculation model established by Deng et al.can estimate the pipe friction resistance in different rock strata at different jacking stages with satisfac-tory outcomes.Further research on the pipe-rock friction coefficient in different rock strata with different pipe–rock contact conditions merits further investigation to better predict the pipe friction resistance in the rock stratum.The research results have certain practica-bility and can provide a reference for similar projects.展开更多
Trenchless technology is often used in congested urban areas or river crossings to install underground pipelines to minimize disturbance to surface traffic or other activities.Pipe jacking is a typical technique appli...Trenchless technology is often used in congested urban areas or river crossings to install underground pipelines to minimize disturbance to surface traffic or other activities.Pipe jacking is a typical technique applied to jack pipe segments between two working shafts.However,the design of the jacking force is usually implemented using empirical methods.It should be emphasized that the jacking force will change for each site,depending on the magnitude of overcut,lubricants,work stoppages,geology and misalignment.A particle method is proposed to estimate the jacking force along the pipe.The microparameters are calibrated for sandy soils in Shenyang,so that the macroscale material behavior can be reproduced using the particle model.Hence,the normal force around the pipe circumference can be derived in the particle model,after which the interface friction coefficient is applied to evaluate the friction resistance mobilized at the soil-pipe interface.A modified Protodyakonov’s arch model can be used to assess the magnitude of earth pressure acting on the shield face.In the end,the combination of friction resistance and face pressure provides the jacking force.The efficacy of the proposed particle method is demonstrated by comparing calculated jacking forces with those measured in the field for three types of jacking machines in sandy soils under the Hun River,Shenyang.展开更多
It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated area.The previous cutters employed to cut RC are insufficient and easily d...It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated area.The previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this question.Based on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut RC.The peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel bars.The LS-DYNA is employed to investigate the cutting performance in advance.The simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel bars.Moreover,the linear cutting platform is adopted to investigate the force ability and damage state of PDC cutters.It is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse aggregates.The patterns occurred in both numerical and experimental results are generally similar.Notably,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 mm.The tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC cutter.It is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.展开更多
The mode of load and deformation of directional drilling string and the expression of trigonometric series of deflection equation are established by means of elastic deformation energy and of the vertical and horizont...The mode of load and deformation of directional drilling string and the expression of trigonometric series of deflection equation are established by means of elastic deformation energy and of the vertical and horizontal bending. A calculation formula for natural frequency of horizontal resonance and rotational speed is derived based on the calculation method by Ritz, with which analysis is made for the cause and affecting factors of the excessive abrasion of heavy-weight drill pipe in high-angle holes so as to provide reference and basis for rational selection of drilling parameters and drilling tools in the future high-angle directional drilling.展开更多
The increase in capacity of displacement piles with time after installation is typically known as soil/pile set-up. A full-scale field test is carried out to observe the set-up effect for open-ended concrete pipe pile...The increase in capacity of displacement piles with time after installation is typically known as soil/pile set-up. A full-scale field test is carried out to observe the set-up effect for open-ended concrete pipe piles jacked into mixed soils. Both the total capacity and the average unit shaft resistance increase approximately linearly with logarithmic time. The average increase rate for unit shaft resistance is 44% per log cycle, while the average increase for total capacity is approximately 21%. A review on case histories for long-term set-up indicates an average set-up rate of approximately 40%. Based on this, the mechanism of pile set-up is discussed in detail and a three-phase model is suggested.展开更多
The vibration and control of pipes conveying fluid is studied. The solid-liquid coupling vibration equations of the pipe conveying fluid are deduced by Hamilton principle.The direct velocity feedback is used to contro...The vibration and control of pipes conveying fluid is studied. The solid-liquid coupling vibration equations of the pipe conveying fluid are deduced by Hamilton principle.The direct velocity feedback is used to control the pipe vibration. The whip response and control are discussed.展开更多
The popularity of trenchless techniques as a means of utility pipeline installation in urban environments,specifically microtunnelling/pipe-jacking,has increased in recent years due to its minimally-disruptive nature ...The popularity of trenchless techniques as a means of utility pipeline installation in urban environments,specifically microtunnelling/pipe-jacking,has increased in recent years due to its minimally-disruptive nature and reduced carbon footprint in comparison to conventional open-cut excavation methods.The response of pipes during the jacking process is complex and is governed by several factors,including ground conditions,the amount and distribution of lubrication,pipe and annulus size,pipeline misalignments and jacking force eccentricity,among others.Design practice remains based on empirical equations and previous drives through similar geology,resulting in uncertainty in jacking force estimates,thereby restricting adoption of the technique.In order to improve our understanding of the pipe-jacking process,pipes incorporating sensors providing real-time measurements of earth pressures,pore water pressures,axial strains and hoop strains can be used;but the number of such studies reported in the literature is small and the potential of instrumentation on routine projects is largely untapped.Moreover,jacking pipe monitoring practice lags behind the state-of-the-art instrumentation techniques used for monitoring other geotechnical infrastructure.The purpose of this paper is to provide a thorough review of learnings from instrumented pipe-jacking case studies and other supporting research,as well as to propose potential solutions to research gaps in the current state of design practice and field monitoring of pipe jacking projects.展开更多
基金the funding support from the National Natural Science Foundations for Young Scientists of China(Grant No.52208391)Doctoral Foundation Project of Guizhou University(Grant No.2021e78).
文摘Previous studies have demonstrated that the surge in jacking force during the Guanjingkou project is caused by the contact conditions of the debris bentonite slurry outside the pipe.Therefore,this paper further systematically investigates the influence of different debris slurry mass ratios(SLRs)and different particle size distributions(PSDs)on the pipe-rock friction characteristics using friction tests.The test results reveal that under the same PSD,an adequate amount of slurry(with an SLR of 1:4)consistently yields the lowest friction coefficient.When the SLR is between 1:2 and 1:3,the viscosity of the slurry reaches its peak,resulting in the highest friction coefficient.Additionally,when the PSD is 1:1:5 and 1:1:15,the friction coefficient is primarily governed by the plowing effect at the contact surface.When the PSD is 5:1:1 and 15:1:1,the friction coefficient is mainly controlled by the void ratio(VR)of debris.In the case of PSDs 1:5:1 and 1:15:1,the friction coefficient is jointly controlled by the adhesion effect of high-viscosity slurry and the plowing effect at the contact surface,and it gradually shifts towards being dominated by the VR as the amount of debris increases.Regardless of the SLRs and PSDs,the continuous deposition of debris and the injection of slurry incessantly exacerbate both the plowing and adhesion effects,creating a vicious cycle.This is the reason why the high-pressure water flushing method can not only fail to resolve the issue but also accelerate the occurrence of the surge in jacking force.
文摘A steel underground pipeline with a diameter of 2.4 m and a total length of 3,617 m(plate thickness of 26 mm)has been constructed in a city in central Hubei,and the engineering,procurement,and construction(EPC)project has been lifted from the upstream channel to supplement water to the downstream lake inside the city.Through preliminary geological survey data,site topographic and geomorphic survey,urban construction,as well as the requirements of the construction party,the preliminary arrangement of working wells and receiving wells as well as the selection and customization of pipe jacking machines have been proposed.Frequency conversion motor and remote monitoring technology are adopted for geotechnical change and long-distance pipe jacking.Through detailed survey,the rock and soil change section as well as gradual change conditions have been determined,the accuracy of construction mechanics calculation and construction operation control have improved,the basis and analysis basis are provided,and some experiences in construction operation are summarized.
文摘The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The rectangular pipe jacking machine occupies a small area during the initial excavation. It is suitable for shallow soil covering and short-distance excavation. It is more economical and applicable than shield machine and has high construction efficiency. During the construction process, technical measures such as attitude measurement and adjustment of pipe jacking machine, surrounding rock grouting and friction reduction can effectively ensure the smooth construction of pipe jacking machine, and provide reference for large section pipe jacking machine in shallow soil construction.
基金the Science and Technology Foundation of Sichuan Department of Land and Resources(SCDLR0609)
文摘By using site observation data and establishing 3D model using ANSYS software, this paper has discussed the strain change of stratum stress during process of jacking-in and the impact of machine head on ground surface under different frontal resistances. Analysis of the two cases shows that soil pressure reaches its maximum point when the soil is right above machine head, and soil stress will gradually decline when machine head passes over it. It also shows that impact brought by pipe-jacking construction on stress change of the surrounding soil is limited. The thesis suggest that road surface should be consolidated and soil condition be improved before construction to prevent loss and disaster caused by road surface deformation, jacking force can be increased so that jacking efficiency can be enhanced when ground stratum is well filled with soil, but the frontal resistance facing machine head should be equal to surrounding soil pressure in order to avoid rise of ground surface.
文摘In Japan when urban infrastructures need to be constructed, the difficulty of utilizing the ground or shallow strata will lead to a more frequent use of the deep strata. The common construction methods are open-cut, pipe jacking, and shield methods. In recent years, a new pipe jacking method has been established that can be adapted to 20 m below the ground or more. Using this method, the drivage machine and the jacking pipe continue to move an underground until the completion of the driving. Therefore an over-cutting area (so-called tail-void) must be formed to lower the friction between the ground and the pipe. The tail-void is filled with lubrications. However, because the stress release from the ground continues to advance when the tail-void is formed, hence there are some challenges required to cope with the stability of the surrounding ground. In order to utilize the pipe jacking method in the deeper strata layers, the theory, analysis and installation of tail-void have to be systemized, and such systematic data must be stored. Therefore, the conditions of tail-void in the deep pipe jacking method are discussed using numerical analyses.
文摘Tunnels in an urban area, in many cases, are constructed in soft ground which contains underground water, near existing facilities and structures. Structural stability for the tunnel and also the nearby structures and facilities is vital in this kind of work. Slurry pipe jacking was firmly established as a special method for the non-disruptive construction of underground pipelines of sewage systems. This method utilizes mud slurry that is formed around the pipes in order to stabilize the surrounding soil. In the pipe roof method the tubing elements that are constructed by slurry pipe jacking are near each other longitudinally, and create a rigid and stable lining before the excavation of the main tunnel. This paper discusses ＇the application of a slurry pipe jacking system on ＇the pipe roof method by means of numerical analysis. Because of the rigid behavior of the lining, the results show little subsidence, making this method a reliable method of constructing large tunnels with small cover in an urban area.
文摘In the construction of municipal road drainage projects,pipe jacking construction is a relatively common construction method.This construction technology can avoid a large amount of excavation work,improve drainage construction efficiency,avoid large-scale damage to the road surface,and exert small traffic impact.Therefore,it is currently widely used in drainage construction,but judging from the current actual application situation,there are still many problems that require further improvement.This article mainly analyzes the advantages of and current technical problems in pipe jacking construction technology in detail,explores corresponding solutions,and lays a foundation for the optimization of municipal road drainage engineering construction.
文摘Traditional construction techniques have a significant impact on the environment and are associated with long construction durations in the construction of municipal rainwater pipelines.Pipe jacking technology,a new type of pipeline construction method,enables non-excavation construction and can address the shortcomings of traditional pipeline construction.This article analyzes the concept and application advantages of pipe jacking technology.Combining engineering examples,it explores the application strategies of pipe jacking technology in the construction process of municipal rainwater pipelines for reference.
文摘In the municipal engineering construction, with the promotion of mechanized construction mode and the increasingly mature and perfect construction technical conditions, the pipe jacking construction gradually develops and progresses in the exploration of construction. In the municipal water supply and drainage construction, we should pay more attention to the application of pipe jacking technology, strictly implement various construction plans, improve the construction effect of water supply and drainage, and give full play to the application value and advantages of pipe jacking technology, which is beneficial to the healthy and stable development of municipal construction in China.
文摘This paper provides a review of the history and development of pipe jacking and microtunneling methods with extensive referencing to the published literature.The application of such methods in comparison with other trenchless technologies is discussed and the various planning,design and construction aspects are introduced.The emphasis of the paper is to trace the academic research and field monitoring results covering critical aspects of design and construction with a particular emphasis on jacking force estimation and the effect of lubrication on jacking forces.
基金Project(2022YJS073)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2024YFE0198500)supported by the National Key Research and Development Program of China:Intergovernmental International Science and Technology Innovation CooperationProject(U2469207)supported by the National Natural Science Foundation Railway Innovation and Development Joint Fund Project,China。
文摘Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.
基金This engineering is a demonstration project for Key Research and Development Project of Guangdong Province under Grant No.2019B111105001part of research related to this engineering was financially supported by the project.
文摘1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced concrete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.
基金supported by the National Natural Science Foundation of China(Grant No.52090082)the Natural Science Foundation of Shandong Province,China(No.ZR202103010505)Fundamental Research Funds for the Central Universities of China(No.22120210428).
文摘The moving trajectory of the pipe-jacking machine(PJM),which primarily determines the end quality of jacked tunnels,must be controlled strictly during the entire jacking process.Developing prediction models to support drivers in performing rectifications in advance can effectively avoid considerable trajectory deviations from the designed jacking axis.Hence,a gated recurrent unit(GRU)-based deep learning framework is proposed herein to dynamically predict the moving trajectory of the PJM.In this framework,operational data are first extracted from a data acquisition system;subsequently,they are preprocessed and used to establish GRU-based multivariate multistep-ahead direct prediction models.To verify the performance of the proposed framework,a case study of a large pipe-jacking project in Shanghai and comparisons with other conventional models(i.e.,long short-term memory(LSTM)network and recurrent neural network(RNN))are conducted.In addition,the effects of the activation function and input time-step length on the prediction performance of the proposed framework are investigated and discussed.The results show that the proposed framework can dynamically and precisely predict the PJM moving trajectory during the pipe-jacking process,with a minimum mean absolute error and root mean squared error(RMSE)of 0.1904 and 0.5011 mm,respectively.The RMSE of the GRU-based models is lower than those of the LSTM-and RNN-based models by 21.46%and 46.40%at the maximum,respectively.The proposed framework is expected to provide an effective decision support for moving trajectory control and serve as a foundation for the application of deep learning in the automatic control of pipe jacking.
基金supported by the National Natural Science Foundation of China(Grant No.12102230)the National Key Research and Development Program of China(Grant No.2018YFC1504802)+1 种基金the Natural Science Foundation Project of Chongqing(Grant No.cstc2018jscx-mszdX0071)the China Postdoctoral Science Foundation(Grant No.2022M711862).
文摘Previous studies on pipe friction resistance are mainly concentrated in the soil layer,whereas the study on that in the rock stratum is limited.To estimate the pipe friction resistance in the rock stratum,the calculation models of pipe friction resistance and their applica-tion conditions were compared first.Then the friction resistance calculation model for pipe jacking in the rock stratum was established and simplified.Lastly,the measured(FM)and the computed(FN)pipe friction resistance was compared to validate the simplified friction resistance calculation model.The following conclusions can be drawn:(1)The existing calculation methods of pipe friction resistance can be well verified in the soil layer but cannot be applied in the rock stratum.(2)Sediment,pipe–rock friction coefficient and mud buoyancy are the main factors affecting the pipe friction resistance in long-distance rock pipe jacking engineering.(3)The simplified calculation model established by Deng et al.can estimate the pipe friction resistance in different rock strata at different jacking stages with satisfac-tory outcomes.Further research on the pipe-rock friction coefficient in different rock strata with different pipe–rock contact conditions merits further investigation to better predict the pipe friction resistance in the rock stratum.The research results have certain practica-bility and can provide a reference for similar projects.
文摘Trenchless technology is often used in congested urban areas or river crossings to install underground pipelines to minimize disturbance to surface traffic or other activities.Pipe jacking is a typical technique applied to jack pipe segments between two working shafts.However,the design of the jacking force is usually implemented using empirical methods.It should be emphasized that the jacking force will change for each site,depending on the magnitude of overcut,lubricants,work stoppages,geology and misalignment.A particle method is proposed to estimate the jacking force along the pipe.The microparameters are calibrated for sandy soils in Shenyang,so that the macroscale material behavior can be reproduced using the particle model.Hence,the normal force around the pipe circumference can be derived in the particle model,after which the interface friction coefficient is applied to evaluate the friction resistance mobilized at the soil-pipe interface.A modified Protodyakonov’s arch model can be used to assess the magnitude of earth pressure acting on the shield face.In the end,the combination of friction resistance and face pressure provides the jacking force.The efficacy of the proposed particle method is demonstrated by comparing calculated jacking forces with those measured in the field for three types of jacking machines in sandy soils under the Hun River,Shenyang.
基金supported by the Shanghai Science and Technology Development Funds(Grant No.20QB1401800)Xuzhou Science and Technology Plan Social Development Key Special Project(Grant No.SHFZZDZX20210017)Yunlong Lake Laboratory of Deep Underground Science and Engineering Project(Grant No.104023006).
文摘It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated area.The previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this question.Based on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut RC.The peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel bars.The LS-DYNA is employed to investigate the cutting performance in advance.The simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel bars.Moreover,the linear cutting platform is adopted to investigate the force ability and damage state of PDC cutters.It is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse aggregates.The patterns occurred in both numerical and experimental results are generally similar.Notably,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 mm.The tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC cutter.It is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.
文摘The mode of load and deformation of directional drilling string and the expression of trigonometric series of deflection equation are established by means of elastic deformation energy and of the vertical and horizontal bending. A calculation formula for natural frequency of horizontal resonance and rotational speed is derived based on the calculation method by Ritz, with which analysis is made for the cause and affecting factors of the excessive abrasion of heavy-weight drill pipe in high-angle holes so as to provide reference and basis for rational selection of drilling parameters and drilling tools in the future high-angle directional drilling.
基金Project supported by the National Natural Science Foundation of China (No. 51078330)the Natural Science Foundation of Zhejiang Province (No. Y1090610),China
文摘The increase in capacity of displacement piles with time after installation is typically known as soil/pile set-up. A full-scale field test is carried out to observe the set-up effect for open-ended concrete pipe piles jacked into mixed soils. Both the total capacity and the average unit shaft resistance increase approximately linearly with logarithmic time. The average increase rate for unit shaft resistance is 44% per log cycle, while the average increase for total capacity is approximately 21%. A review on case histories for long-term set-up indicates an average set-up rate of approximately 40%. Based on this, the mechanism of pile set-up is discussed in detail and a three-phase model is suggested.
文摘The vibration and control of pipes conveying fluid is studied. The solid-liquid coupling vibration equations of the pipe conveying fluid are deduced by Hamilton principle.The direct velocity feedback is used to control the pipe vibration. The whip response and control are discussed.
基金funded by the Science Foundation Ireland Research Centre in Applied Geosciences(SFI-iCRAG),with Ward and Burke Construction Limited as the industry partner.
文摘The popularity of trenchless techniques as a means of utility pipeline installation in urban environments,specifically microtunnelling/pipe-jacking,has increased in recent years due to its minimally-disruptive nature and reduced carbon footprint in comparison to conventional open-cut excavation methods.The response of pipes during the jacking process is complex and is governed by several factors,including ground conditions,the amount and distribution of lubrication,pipe and annulus size,pipeline misalignments and jacking force eccentricity,among others.Design practice remains based on empirical equations and previous drives through similar geology,resulting in uncertainty in jacking force estimates,thereby restricting adoption of the technique.In order to improve our understanding of the pipe-jacking process,pipes incorporating sensors providing real-time measurements of earth pressures,pore water pressures,axial strains and hoop strains can be used;but the number of such studies reported in the literature is small and the potential of instrumentation on routine projects is largely untapped.Moreover,jacking pipe monitoring practice lags behind the state-of-the-art instrumentation techniques used for monitoring other geotechnical infrastructure.The purpose of this paper is to provide a thorough review of learnings from instrumented pipe-jacking case studies and other supporting research,as well as to propose potential solutions to research gaps in the current state of design practice and field monitoring of pipe jacking projects.
