A series of true triaxial unloading tests are conducted on sandstone specimens with a single structural plane to investigate their mechanical behaviors and failure characteristics under different in situ stress states...A series of true triaxial unloading tests are conducted on sandstone specimens with a single structural plane to investigate their mechanical behaviors and failure characteristics under different in situ stress states.The experimental results indicate that the dip angle of structural plane(θ)and the intermediate principal stress(σ2)have an important influence on the peak strength,cracking mode,and rockburst severity.The peak strength exhibits a first increase and then decrease as a function ofσ2 for a constantθ.However,whenσ2 is constant,the maximum peak strength is obtained atθof 90°,and the minimum peak strength is obtained atθof 30°or 45°.For the case of an inclined structural plane,the crack type at the tips of structural plane transforms from a mix of wing and anti-wing cracks to wing cracks with an increase inσ2,while the crack type around the tips of structural plane is always anti-wing cracks for the vertical structural plane,accompanied by a series of tensile cracks besides.The specimens with structural plane do not undergo slabbing failure regardless ofθ,and always exhibit composite tensile-shear failure whatever theσ2 value is.With an increase inσ2 andθ,the intensity of the rockburst is consistent with the tendency of the peak strength.By analyzing the relationship between the cohesion(c),internal friction angle(φ),andθin sandstone specimens,we incorporateθinto the true triaxial unloading strength criterion,and propose a modified linear Mogi-Coulomb criterion.Moreover,the crack propagation mechanism at the tips of structural plane,and closure degree of the structural plane under true triaxial unloading conditions are also discussed and summarized.This study provides theoretical guidance for stability assessment of surrounding rocks containing geological structures in deep complex stress environments.展开更多
The rise of deep learning has brought about transformative advancements in both scientific research and engineering applications.The 2024 Nobel Prizes,particularly in Physics and Chemistry,highlighted the revolutionar...The rise of deep learning has brought about transformative advancements in both scientific research and engineering applications.The 2024 Nobel Prizes,particularly in Physics and Chemistry,highlighted the revolutionary impact of deep learning,with AlphaFold’s breakthrough in protein structure prediction exemplifying its potential.This review explores the historical evolution of deep learning,from its foundational theories in neural networks and connectionism to its modern applications in various fields.Focus is given to its use in geotechnical engineering,particularly in geological disaster prediction,tunnel safety monitoring,and structural design optimization.The integration of deep learning models such as Convolutional Neural Networks(CNNs),Recurrent Neural Networks(RNNs),and Transformers has enabled significant progress in analyzing complex,unstructured data,offering innovative solutions to longstanding engineering challenges.The review also examines the opportunities and challenges faced by the field,advocating for interdisciplinary collaboration and open data sharing to further unlock deep learning’s potential in advancing both scientific and engineering disciplines.As deep learning continues to evolve,it promises to drive further innovation,shaping the future of engineering practices and scientific discovery.展开更多
During the development blasting of circular tunnels, the detonation of multiple blastholes arranged onconcentric circles induces a complex dynamic response in the surrounding rocks. This process involvesmultiple blast...During the development blasting of circular tunnels, the detonation of multiple blastholes arranged onconcentric circles induces a complex dynamic response in the surrounding rocks. This process involvesmultiple blast loadings, static stress unloadings, and stress redistributions. In this study, the dynamicstresses of the surrounding rocks during development blasting, considering multiple blasting-unloadingstages with exponential paths and triangular paths (linear simplified paths of exponential paths), aresolved based on the dynamic theory and the Fourier transform method. Then, a corresponding discreteelement model is established using particle flow code (PFC). The multiple-stage dynamic stress andfracture distribution under different in situ stress levels and lateral coefficients are investigated. Theoreticalresults indicate that the peak compressive stresses in the surrounding rocks induced by bothtriangular and exponential paths are equal, while the triangular path generates greater additional dynamictensile stresses, particularly in the circumferential direction, compared to the exponential path.Numerical results show that the exponential path causes less dynamic circumferential tensile damageand forms fewer radial fractures than the triangular path in the first few blast stages;conversely, itexacerbates the damage and instability in the final blasting-unloading stage and forms more circumferentialfractures. Furthermore, the in situ stress determines which of the two opposite effects isdominant. Therefore, when using overly simplified triangular paths to evaluate the stability of surroundingrocks, potential overestimation or underestimation caused by different failure mechanismsshould be considered. Specifically, under high horizontal and vertical stresses, the static stress redistributionwith layer-by-layer blasting suppresses dynamic circumferential tensile and radial compressivedamage. The damage evolution of surrounding rocks in multi-stage blasting under different in situstresses is summarized and classified according to the damage mechanism and characteristics, which canguide blasting and support design.展开更多
The study was conducted to identify indoor air quality and the level of thermal comfort in various selected locations in Faculty of Engineering and Built Environment （FKAB）, University Kebangsaan Malaysia （UKM） wi...The study was conducted to identify indoor air quality and the level of thermal comfort in various selected locations in Faculty of Engineering and Built Environment （FKAB）, University Kebangsaan Malaysia （UKM） with built-up area of 250,936 fie. The indoor air quality and thermal comfort were measured at various selected locations by using indoor air quality equipment （Thermal Comfort SERI）. The thermal comfort assessments are based on Malaysian Code of Practice Indoor Air Quality 2005 and Moderate Thermal Environments-Determination of the PMV and PPD indices specification of the condition for thermal comfort （ISO7730：1994） From the data analysis, the FKAB building is considered inadequately vented space. The concentration of CO2 for all sampling area evaluated exceeds the recommended concentration （〉 1000 ppm）. The ventilation system used in FKAB building is designed by delivering fix amount of fresh air into building from external building without consideration on the number of occupants. This common ventilation design will increase the amount of CO2 dramatically all day long and these reflect the inefficiency of energy used. The faculty needs to be equipped with a comprehensive energy management system that can allow detailed documentation of continuous performance of all energy system and consumption in the building.展开更多
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
Introduction: This study investigates the Experimental and Theoretical Investigation of Steel and Glass Fiber Reinforced Polymer (GFRP) Reinforced Slab Incorporating Alccofine and M-sand. Objective: Specific objective...Introduction: This study investigates the Experimental and Theoretical Investigation of Steel and Glass Fiber Reinforced Polymer (GFRP) Reinforced Slab Incorporating Alccofine and M-sand. Objective: Specific objectives include evaluating the mechanical properties and structural behaviour of steel and GFRP-reinforced one-way slabs and comparing experimental and theoretical predictions. Methods: Four different mix proportions were arrived at, comprising both conventional concrete and Alccofine-based concrete. In each formulation, a combination of normal river sand and M-sand was utilized. Results: Concrete with Alccofine exhibits superior mechanical properties, while M-sand incorporation minimally affects strength but reduces reliance on natural sand. GFRP-reinforced slabs display distinct brittle behaviour with significant deflections post-cracking, contrasting steel-reinforced slabs’ gradual, ductile failure. Discrepancies between experimental data and design recommendations underscore the need for guideline refinement. Conclusion: Alccofine and M-sand enhance concrete properties, but reinforcement type significantly influences slab behaviour. GFRP-reinforced slabs, though exhibiting lower values than steel, offer advantages in harsh environments, warranting further optimization.展开更多
Landslides and debris flows are typical geo-hazards which occur in hilly or mountainous regions. Debris flows may result from landslides. Geotechnical instrumentation plays an important role in monitoring and warning ...Landslides and debris flows are typical geo-hazards which occur in hilly or mountainous regions. Debris flows may result from landslides. Geotechnical instrumentation plays an important role in monitoring and warning of landslides and resulted debris flows. Traditional technologies for monitoring landslides and debris flows have certain limitations. The new optical fiber sensors presented in this paper can overcome those limitations. This paper presents two new optical fiber sensor systems: one is the Fiber Bragg Grating (FBG)-based in-place inclinometer for monitoring landslides and the other is the FBG-based column-net system for monitoring debris flows. This paper presents the calibration results of FBG-based in-place inclinometers in laboratory. It is found that the calibration results are in good agreement with theoretical results. Both the FBG-based in-place inclinometers and the FBG-based column-net system have been installed at a site in Weijiagou valley, Beichuan County, Sichuan Province of China. Some preliminary results have been obtained and reported in the paper. The advantages of the FBG monitoring systems and their potential applications are also presented.展开更多
The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb：tures were prepared. The concrete mi...The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb：tures were prepared. The concrete mixtures in series I had a water-to-binder ratio and a cement content of 0.55 and 410 kg/ m^3 , respectively. The concrete rnixtures in series II had a water-to-binder ratio and a cement content of 0.45 and 400 kg/ ml respectively. Recycled aggregate was ased as 20% , 50% , and 100% replacements of natural coarse aggregate in the concrete mixtures in both series. In cutdition, fly ash was used as 0% , 25% and 35% by weight replacements of cement. The results show that the compressive strengths of the concrete decreased as the recycled aggregate and the fly ash contents increased. The total porosity and average porosity diameter of the concrete increased us the recycled aggregate content increased. Furtherrruore , an increase in the recycled aggregate content decreased the resistance to chloride ion penetration. Nevertheless, the replacement of cement by 25% fly ush improved the resistance to chloride ion penetration and pore diameters and reduced the total porosity of the recycled aggregate concrete.展开更多
Air samples were collected simultaneously at platform,mezzanine and outdoor in five typical stations of subway system in Shanghai,China using stainless steel canisters and analyzed by gas chromatography-mass selective...Air samples were collected simultaneously at platform,mezzanine and outdoor in five typical stations of subway system in Shanghai,China using stainless steel canisters and analyzed by gas chromatography-mass selective detector （GC-MSD） after cryogenic pre-concentration.Benzene,toluene,ethylbenzene and xylenes （BTEX） at the platforms and mezzanines inside the stations averaged （10.3±2.1）,（38.7±9.0）,（19.4±10.1） and （30.0±11.1） μg/m 3,respectively;while trichloroethylene （TrCE）,tetrachloroethylene （TeCE） and para-dichlorobenzene （pDCB）,vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of （3.6±1.3）,（1.3±0.5）,（4.1±1.1）,（2.2±1.1） and （1.2±0.3） μg/m 3,respectively.Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor （platforms and mezzanines） than outdoor with average indoor/outdoor （I/O） ratios of 1.1–9.5,whereas no significant indoor/outdoor differences were found except for benzene and TrCE.The highly significant mutual correlations （p0.01） for BTEX between indoor and outdoor and their significant correlation （p0.05） with methyl tert-butyl ether （MTBE）,a marker of traffic-related emission without other indoor and outdoor sources,indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source.TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air,especially in the mezzanines.展开更多
Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor （I/O） ratio, correlations and sources, of indoor and outdoor PM2.5 and elem...Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor （I/O） ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission （PIXE） method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.展开更多
This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization metho...This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization (MPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm. Moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design of the footing and the retaining structure utilizing the proposed method.展开更多
To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Ba...To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Bay and Xuhu Bay) of the Taihu Lake,East China,were studied.Pb and Zn showed elevated concentrations in the sediments from both areas,although sedimentation history and degree of pollution are different between the two bays.In the Meiliang Bay,both Pb and Zn pollutions started in the late 1970's,the same time as the beginning of eutrophication of the lake,while the in the Xuhu Bay the metal contamination started since recent 10 years.The concentrations of acid-leachable Pb in the sediments from the Meiliang Bay are correlated with the historical eutrophication process.Before the eutrophication and heavy metal pollution,the chemical properties of the lake sediments were the same as the source compositions of the Xiashu loess.Both Pb and Zn in the sediments mainly occur in leachable forms by nitric or hydrochloric acid,whilst most of Cu is in residual fraction.The results indicate that both Pb and Zn may have higher mobility and bioavailability in water and biology than Cu.展开更多
Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined acti...Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.展开更多
The strength of geomaterials is typically predicted by the Mohr-Coulomb yield criterion in slope stability analysis.The tensile strength of soils in this yield criterion,which is an extrapolation of the triaxial compr...The strength of geomaterials is typically predicted by the Mohr-Coulomb yield criterion in slope stability analysis.The tensile strength of soils in this yield criterion,which is an extrapolation of the triaxial compression test results,is usually overestimated.Generally,the influences of tensile stresses in slopes are evaluated by two approaches:1)introducing cracks to eliminate the tensile stresses in slopes,and 2)truncating the strength envelope to reduce the tensile strength of the soils.However,comparative analyses of the two approaches have not been fully implemented,especially under dynamic conditions.In this study,three slope failure mechanisms corresponding to the predictions of slope stability by the mentioned two approaches subjected to seismic loadings are systematically evaluated.The stability factor considering the pre-existing crack,crack formation,and tension cut-off are compared one another.The most unfavorable crack locations corresponding to the different mechanisms are evaluated.The influence of tensile strength on the factor of safety of slopes is estimated as well.Further,the critical acceleration and the permanent displacement of slopes with pre-existing crack,and tension cut-off are derived in the framework of the kinematic theorem of limit analysis.The vertical effects of seismic coefficient on critical acceleration and permanent displacement are discussed.Conclusions can be drawn that the consideration of tension zone effects can sharply reduce the stability factor of slopes,especially for steep slopes and large horizontal seismic loads;different from the static condition,the slope with pre-existing crack is not always the most vulnerable to collapse,the tension cut-off mechanism in steep slopes may predict the lowest stability factor.In addition,the calculation shows that an evidently increase in the slope displacement is induced by the increasing downward vertical loads,while a decrease occurs if the vertical loads are upward.展开更多
An incubation experiment was carried out on plateau and slope fields to investigate the effect of plant age and rock phosphate （RP） on the organic resource （OR） quality and available N and P release of the legume ...An incubation experiment was carried out on plateau and slope fields to investigate the effect of plant age and rock phosphate （RP） on the organic resource （OR） quality and available N and P release of the legume residues, including standing biomass and surface litter. The legumes, Mueuna pruriens （L.） and Lablab purpureus （L.）, were treated with or without Togo rock phosphate （RP） and were sampled at 12, 18, 24 and 30 weeks after planting. Results showed that the application of RP significantly affected the P content of the legume residues on the plateau field for the first 18 weeks, but not the other OR quality parameters, nor their N mineralization, or P release parameters. Although application of RP led to higher P contents in both legumes on the plateau field, the P contents were still far below those observed on the slope field. For both species, the biomass age appeared to have a major impact on their N, P, and polyphenol contents, but not on the liguin content. At 24 weeks, both legume N and P contents dropped to about half their values at 12 weeks of age. Residue age also significantly affected N mineralization both with and without RP addition and the net Olsen-P with RP addition. The younger residues generally led to higher N mineralization and net Olsen-P content than the older residues. The best immediate responses to herbaceous legume addition were expected from younger materials, but often at the cost of the total biomass produced and the possibility to produce seeds. The production of seeds, however, could be potentially implemented on a small area of legumes, thus invariably allowing for maturity and seed production.展开更多
A kind of photoelectrode was innovated by anodising titanium mesh in H 2SO 4 solution and photo reduced in HAuCl 4 solution and named Ti/Au TiO 2 mesh electrode. The structural and surface morphology of the Ti/Au TiO ...A kind of photoelectrode was innovated by anodising titanium mesh in H 2SO 4 solution and photo reduced in HAuCl 4 solution and named Ti/Au TiO 2 mesh electrode. The structural and surface morphology of the Ti/Au TiO 2 mesh was examined by X ray diffraction, laser Raman spectra, scanning electronic microscopy(SEM) and X ray photoelectron spectroscopy respectively. The results indicate that its crystal structure, morphology and the size of pore are affected greatly by gold deposition. XPS measurement shows that the valence band of Ti/TiO 2 has two peaks: a wide one at 4.97 eV and a narrow one at 6.61 eV, which correspond mainly to π(nonbonding) and σ (bonding) O 2p orbitals. The emission intensity of O 2p orbitals becomes stronger and the width of the valence band increases with the increase of Au content. And the emission of nonbonding shifts toward lower binding energy and that of bonding O 2p orbitals shifts toward higher binding energy. The photoelectrocatalytic(PEC) oxidation of humic acid(HA) was investigated in terms of TOC. The PEC oxidation efficiency of Ti/Au TiO 2 mesh with optimal content of gold is higher than that of Ti/TiO 2 mesh. It is suggested that the recombination of electrons and holes is hindered owing to gold deposition. The investigation shows that PEC oxidation is a convenient way to mineralize organic matter for water treatment.展开更多
Fibre-reinforced polymer (FRP) composites were widely utilized in civil engineering structures as the retrofit of reinforced concrete (RC) columns. To design FRP jackets safely and economically, the behaviour of such ...Fibre-reinforced polymer (FRP) composites were widely utilized in civil engineering structures as the retrofit of reinforced concrete (RC) columns. To design FRP jackets safely and economically, the behaviour of such columns should be predicted first. This paper is concerned with the analysis and behaviour of FRP-confined RC circular and rectangular short col- umns subjected to eccentric loading. A simple design-oriented stress-strain model for FRP-confined concrete in a section analysis was first proposed. The accuracy was then proved by two test data. Following that, a parametric study including amount of FRP confinement, FRP strain capacity, unconfined concrete strength and shape of column section is provided. Some conclusions were obtained at the end of the paper. The work here will provide a comprehensive understanding of the behaviour of FRP-confined concrete columns. The simplicity of the model also enables a simple equivalent stress block to be developed for direct use in practical design.展开更多
The relationship between the emission of ozone precursors and the chemical production of tropospheric ozone （03） in the Pearl River Delta Region （PRD） was studied using numerical simulation. The aim of this study ...The relationship between the emission of ozone precursors and the chemical production of tropospheric ozone （03） in the Pearl River Delta Region （PRD） was studied using numerical simulation. The aim of this study was to examine the volatile organic compound （VOC）- or nitrogen oxide （NO~ =NO＋NO2）- limited conditions at present and when surface temperature is increasing due to global warming, thus to make recommendations for future ozone abatement policies for the PRD region. The model used for this application is the U.S. Environmental Protection Agency＇s （EPA＇s） third-generation air-quality modeling system; it consists of the mesoscale meteorological model MM5 and the chemical transport model named Community Multi-scale Air Quality （CMAQ）. A series of sensitivity tests were conducted to assess the influence of VOC and NO~ variations on ozone production. Tropical cyclone was shown to be one of the important synoptic weather patterns leading to ozone pollution. The simulations were based on a tropical- cyclone-related episode that occurred during 14-16 September 2004. The results show that, in the future, the control strategy for emissions should be tightened. To reduce the current level of ozone to meet the Hong Kong Environmental Protection Department （EPD） air-quality objective （hourly average of 120 ppb）, emphasis should be put on restricting the increase of NOx emissions. Furthermore, for a wide range of possible changes in precursor emissions, temperature increase will increase the ozone peak in the PRD region; the areas affected by photochemical smog are growing wider, but the locations of the ozone plume are rather invariant.展开更多
This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation （LES） model is developed to simulate th...This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation （LES） model is developed to simulate the buoyant jet in a stagnant ambient and JONSWAP random waves. By comparison of velocity and concentration fields, it is found that the buoyant jet exhibits faster decay of centerline velocity, wider lateral spreading and larger initial dilution under the wave effect, indicating that wave dynamics improves the jet entrainment and mixing in the near field, and subsequently mitigate the jet impacts in the far field. The effect of buoyancy force on the jet behaviours in the random waves is also numerically investigated. The results show that the wave effect on the jet entrainment and mixing is considerably weakened under the existence of buoyancy force, resulting in a slower decay rate of centerline velocity and a narrower jet width for the jet with initial buoyancy.展开更多
基金supports from the National Natural Science Foundation of China (Grant Nos.52004143 and 52374095)the open fund for the Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines (Grant No.SKLMRDPC21KF06).
文摘A series of true triaxial unloading tests are conducted on sandstone specimens with a single structural plane to investigate their mechanical behaviors and failure characteristics under different in situ stress states.The experimental results indicate that the dip angle of structural plane(θ)and the intermediate principal stress(σ2)have an important influence on the peak strength,cracking mode,and rockburst severity.The peak strength exhibits a first increase and then decrease as a function ofσ2 for a constantθ.However,whenσ2 is constant,the maximum peak strength is obtained atθof 90°,and the minimum peak strength is obtained atθof 30°or 45°.For the case of an inclined structural plane,the crack type at the tips of structural plane transforms from a mix of wing and anti-wing cracks to wing cracks with an increase inσ2,while the crack type around the tips of structural plane is always anti-wing cracks for the vertical structural plane,accompanied by a series of tensile cracks besides.The specimens with structural plane do not undergo slabbing failure regardless ofθ,and always exhibit composite tensile-shear failure whatever theσ2 value is.With an increase inσ2 andθ,the intensity of the rockburst is consistent with the tendency of the peak strength.By analyzing the relationship between the cohesion(c),internal friction angle(φ),andθin sandstone specimens,we incorporateθinto the true triaxial unloading strength criterion,and propose a modified linear Mogi-Coulomb criterion.Moreover,the crack propagation mechanism at the tips of structural plane,and closure degree of the structural plane under true triaxial unloading conditions are also discussed and summarized.This study provides theoretical guidance for stability assessment of surrounding rocks containing geological structures in deep complex stress environments.
基金support provided by the Hebei Province Full-Time Recruitment of National High-Level Innovative Talents Research Project(Grant No.2023HBQZYCSB004).
文摘The rise of deep learning has brought about transformative advancements in both scientific research and engineering applications.The 2024 Nobel Prizes,particularly in Physics and Chemistry,highlighted the revolutionary impact of deep learning,with AlphaFold’s breakthrough in protein structure prediction exemplifying its potential.This review explores the historical evolution of deep learning,from its foundational theories in neural networks and connectionism to its modern applications in various fields.Focus is given to its use in geotechnical engineering,particularly in geological disaster prediction,tunnel safety monitoring,and structural design optimization.The integration of deep learning models such as Convolutional Neural Networks(CNNs),Recurrent Neural Networks(RNNs),and Transformers has enabled significant progress in analyzing complex,unstructured data,offering innovative solutions to longstanding engineering challenges.The review also examines the opportunities and challenges faced by the field,advocating for interdisciplinary collaboration and open data sharing to further unlock deep learning’s potential in advancing both scientific and engineering disciplines.As deep learning continues to evolve,it promises to drive further innovation,shaping the future of engineering practices and scientific discovery.
基金supported by the National Natural Science Foundation of China(Grant Nos.51927808 and 41630642)the Postgraduate Innovation Fund Project of Hunan Province(Grant No.CX20200242).
文摘During the development blasting of circular tunnels, the detonation of multiple blastholes arranged onconcentric circles induces a complex dynamic response in the surrounding rocks. This process involvesmultiple blast loadings, static stress unloadings, and stress redistributions. In this study, the dynamicstresses of the surrounding rocks during development blasting, considering multiple blasting-unloadingstages with exponential paths and triangular paths (linear simplified paths of exponential paths), aresolved based on the dynamic theory and the Fourier transform method. Then, a corresponding discreteelement model is established using particle flow code (PFC). The multiple-stage dynamic stress andfracture distribution under different in situ stress levels and lateral coefficients are investigated. Theoreticalresults indicate that the peak compressive stresses in the surrounding rocks induced by bothtriangular and exponential paths are equal, while the triangular path generates greater additional dynamictensile stresses, particularly in the circumferential direction, compared to the exponential path.Numerical results show that the exponential path causes less dynamic circumferential tensile damageand forms fewer radial fractures than the triangular path in the first few blast stages;conversely, itexacerbates the damage and instability in the final blasting-unloading stage and forms more circumferentialfractures. Furthermore, the in situ stress determines which of the two opposite effects isdominant. Therefore, when using overly simplified triangular paths to evaluate the stability of surroundingrocks, potential overestimation or underestimation caused by different failure mechanismsshould be considered. Specifically, under high horizontal and vertical stresses, the static stress redistributionwith layer-by-layer blasting suppresses dynamic circumferential tensile and radial compressivedamage. The damage evolution of surrounding rocks in multi-stage blasting under different in situstresses is summarized and classified according to the damage mechanism and characteristics, which canguide blasting and support design.
文摘The study was conducted to identify indoor air quality and the level of thermal comfort in various selected locations in Faculty of Engineering and Built Environment （FKAB）, University Kebangsaan Malaysia （UKM） with built-up area of 250,936 fie. The indoor air quality and thermal comfort were measured at various selected locations by using indoor air quality equipment （Thermal Comfort SERI）. The thermal comfort assessments are based on Malaysian Code of Practice Indoor Air Quality 2005 and Moderate Thermal Environments-Determination of the PMV and PPD indices specification of the condition for thermal comfort （ISO7730：1994） From the data analysis, the FKAB building is considered inadequately vented space. The concentration of CO2 for all sampling area evaluated exceeds the recommended concentration （〉 1000 ppm）. The ventilation system used in FKAB building is designed by delivering fix amount of fresh air into building from external building without consideration on the number of occupants. This common ventilation design will increase the amount of CO2 dramatically all day long and these reflect the inefficiency of energy used. The faculty needs to be equipped with a comprehensive energy management system that can allow detailed documentation of continuous performance of all energy system and consumption in the building.
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.
文摘Introduction: This study investigates the Experimental and Theoretical Investigation of Steel and Glass Fiber Reinforced Polymer (GFRP) Reinforced Slab Incorporating Alccofine and M-sand. Objective: Specific objectives include evaluating the mechanical properties and structural behaviour of steel and GFRP-reinforced one-way slabs and comparing experimental and theoretical predictions. Methods: Four different mix proportions were arrived at, comprising both conventional concrete and Alccofine-based concrete. In each formulation, a combination of normal river sand and M-sand was utilized. Results: Concrete with Alccofine exhibits superior mechanical properties, while M-sand incorporation minimally affects strength but reduces reliance on natural sand. GFRP-reinforced slabs display distinct brittle behaviour with significant deflections post-cracking, contrasting steel-reinforced slabs’ gradual, ductile failure. Discrepancies between experimental data and design recommendations underscore the need for guideline refinement. Conclusion: Alccofine and M-sand enhance concrete properties, but reinforcement type significantly influences slab behaviour. GFRP-reinforced slabs, though exhibiting lower values than steel, offer advantages in harsh environments, warranting further optimization.
基金supported by research grants of The Hong Kong Polytechnic University (Grant Nos. G-YE54 and 1-BB7U)supported by the State Key Fundamental Research (973) program project (Grant No. 2008CB425802)supported by a project entitled "Analysis of Geological and Mechanics Reasons Causing Damage of Bridge Structures during Wenchuan Earthquake and Recommendations for Reconstruction" (A/C No. 85G0)
文摘Landslides and debris flows are typical geo-hazards which occur in hilly or mountainous regions. Debris flows may result from landslides. Geotechnical instrumentation plays an important role in monitoring and warning of landslides and resulted debris flows. Traditional technologies for monitoring landslides and debris flows have certain limitations. The new optical fiber sensors presented in this paper can overcome those limitations. This paper presents two new optical fiber sensor systems: one is the Fiber Bragg Grating (FBG)-based in-place inclinometer for monitoring landslides and the other is the FBG-based column-net system for monitoring debris flows. This paper presents the calibration results of FBG-based in-place inclinometers in laboratory. It is found that the calibration results are in good agreement with theoretical results. Both the FBG-based in-place inclinometers and the FBG-based column-net system have been installed at a site in Weijiagou valley, Beichuan County, Sichuan Province of China. Some preliminary results have been obtained and reported in the paper. The advantages of the FBG monitoring systems and their potential applications are also presented.
基金Funded by the Environment and Conservation Fund, the WooWheelock Green Fund andthe Hong Kong Polytechnic University
文摘The effects of fly ash on the compressive strength, pore size distribution and chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mb：tures were prepared. The concrete mixtures in series I had a water-to-binder ratio and a cement content of 0.55 and 410 kg/ m^3 , respectively. The concrete rnixtures in series II had a water-to-binder ratio and a cement content of 0.45 and 400 kg/ ml respectively. Recycled aggregate was ased as 20% , 50% , and 100% replacements of natural coarse aggregate in the concrete mixtures in both series. In cutdition, fly ash was used as 0% , 25% and 35% by weight replacements of cement. The results show that the compressive strengths of the concrete decreased as the recycled aggregate and the fly ash contents increased. The total porosity and average porosity diameter of the concrete increased us the recycled aggregate content increased. Furtherrruore , an increase in the recycled aggregate content decreased the resistance to chloride ion penetration. Nevertheless, the replacement of cement by 25% fly ush improved the resistance to chloride ion penetration and pore diameters and reduced the total porosity of the recycled aggregate concrete.
基金supported by the National Natural Science Foundation of China (No. 40821003)the Guangdong Natural Science Foundation (No. 7118013)the State Key Laboratory of Organic Geochemistry and the Hong Kong Polytechnic University Joint Student Program
文摘Air samples were collected simultaneously at platform,mezzanine and outdoor in five typical stations of subway system in Shanghai,China using stainless steel canisters and analyzed by gas chromatography-mass selective detector （GC-MSD） after cryogenic pre-concentration.Benzene,toluene,ethylbenzene and xylenes （BTEX） at the platforms and mezzanines inside the stations averaged （10.3±2.1）,（38.7±9.0）,（19.4±10.1） and （30.0±11.1） μg/m 3,respectively;while trichloroethylene （TrCE）,tetrachloroethylene （TeCE） and para-dichlorobenzene （pDCB）,vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of （3.6±1.3）,（1.3±0.5）,（4.1±1.1）,（2.2±1.1） and （1.2±0.3） μg/m 3,respectively.Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor （platforms and mezzanines） than outdoor with average indoor/outdoor （I/O） ratios of 1.1–9.5,whereas no significant indoor/outdoor differences were found except for benzene and TrCE.The highly significant mutual correlations （p0.01） for BTEX between indoor and outdoor and their significant correlation （p0.05） with methyl tert-butyl ether （MTBE）,a marker of traffic-related emission without other indoor and outdoor sources,indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source.TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air,especially in the mezzanines.
基金Project supported by the Foundation of Research Grants Council of Hong Kong (No. PolyU 5145/03E) the National Natural Science Foundation of China (No. 40121303).
文摘Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor （I/O） ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission （PIXE） method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.
文摘This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization (MPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm. Moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design of the footing and the retaining structure utilizing the proposed method.
基金supported by 973 Project on the Processes of Lake Eutrophication and the Mechanism of Cyanobacterial Blooming (2002CB412300)National Survey of Land and Source (200420130002)
文摘To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Bay and Xuhu Bay) of the Taihu Lake,East China,were studied.Pb and Zn showed elevated concentrations in the sediments from both areas,although sedimentation history and degree of pollution are different between the two bays.In the Meiliang Bay,both Pb and Zn pollutions started in the late 1970's,the same time as the beginning of eutrophication of the lake,while the in the Xuhu Bay the metal contamination started since recent 10 years.The concentrations of acid-leachable Pb in the sediments from the Meiliang Bay are correlated with the historical eutrophication process.Before the eutrophication and heavy metal pollution,the chemical properties of the lake sediments were the same as the source compositions of the Xiashu loess.Both Pb and Zn in the sediments mainly occur in leachable forms by nitric or hydrochloric acid,whilst most of Cu is in residual fraction.The results indicate that both Pb and Zn may have higher mobility and bioavailability in water and biology than Cu.
基金supported by the Universiti Kebangsaan Malaysia Grant(Grant No.GUP-2014-077)
文摘Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.
基金The authors would like to appreciate the supports from the National Natural Science Foundation of China(Grant Nos.42077236,51608454,51609204,and 41977213).
文摘The strength of geomaterials is typically predicted by the Mohr-Coulomb yield criterion in slope stability analysis.The tensile strength of soils in this yield criterion,which is an extrapolation of the triaxial compression test results,is usually overestimated.Generally,the influences of tensile stresses in slopes are evaluated by two approaches:1)introducing cracks to eliminate the tensile stresses in slopes,and 2)truncating the strength envelope to reduce the tensile strength of the soils.However,comparative analyses of the two approaches have not been fully implemented,especially under dynamic conditions.In this study,three slope failure mechanisms corresponding to the predictions of slope stability by the mentioned two approaches subjected to seismic loadings are systematically evaluated.The stability factor considering the pre-existing crack,crack formation,and tension cut-off are compared one another.The most unfavorable crack locations corresponding to the different mechanisms are evaluated.The influence of tensile strength on the factor of safety of slopes is estimated as well.Further,the critical acceleration and the permanent displacement of slopes with pre-existing crack,and tension cut-off are derived in the framework of the kinematic theorem of limit analysis.The vertical effects of seismic coefficient on critical acceleration and permanent displacement are discussed.Conclusions can be drawn that the consideration of tension zone effects can sharply reduce the stability factor of slopes,especially for steep slopes and large horizontal seismic loads;different from the static condition,the slope with pre-existing crack is not always the most vulnerable to collapse,the tension cut-off mechanism in steep slopes may predict the lowest stability factor.In addition,the calculation shows that an evidently increase in the slope displacement is induced by the increasing downward vertical loads,while a decrease occurs if the vertical loads are upward.
基金supported by the Belgian General Administration for Development Cooperation and the International Instituteof Tropical Agriculture (IITA).
文摘An incubation experiment was carried out on plateau and slope fields to investigate the effect of plant age and rock phosphate （RP） on the organic resource （OR） quality and available N and P release of the legume residues, including standing biomass and surface litter. The legumes, Mueuna pruriens （L.） and Lablab purpureus （L.）, were treated with or without Togo rock phosphate （RP） and were sampled at 12, 18, 24 and 30 weeks after planting. Results showed that the application of RP significantly affected the P content of the legume residues on the plateau field for the first 18 weeks, but not the other OR quality parameters, nor their N mineralization, or P release parameters. Although application of RP led to higher P contents in both legumes on the plateau field, the P contents were still far below those observed on the slope field. For both species, the biomass age appeared to have a major impact on their N, P, and polyphenol contents, but not on the liguin content. At 24 weeks, both legume N and P contents dropped to about half their values at 12 weeks of age. Residue age also significantly affected N mineralization both with and without RP addition and the net Olsen-P with RP addition. The younger residues generally led to higher N mineralization and net Olsen-P content than the older residues. The best immediate responses to herbaceous legume addition were expected from younger materials, but often at the cost of the total biomass produced and the possibility to produce seeds. The production of seeds, however, could be potentially implemented on a small area of legumes, thus invariably allowing for maturity and seed production.
文摘A kind of photoelectrode was innovated by anodising titanium mesh in H 2SO 4 solution and photo reduced in HAuCl 4 solution and named Ti/Au TiO 2 mesh electrode. The structural and surface morphology of the Ti/Au TiO 2 mesh was examined by X ray diffraction, laser Raman spectra, scanning electronic microscopy(SEM) and X ray photoelectron spectroscopy respectively. The results indicate that its crystal structure, morphology and the size of pore are affected greatly by gold deposition. XPS measurement shows that the valence band of Ti/TiO 2 has two peaks: a wide one at 4.97 eV and a narrow one at 6.61 eV, which correspond mainly to π(nonbonding) and σ (bonding) O 2p orbitals. The emission intensity of O 2p orbitals becomes stronger and the width of the valence band increases with the increase of Au content. And the emission of nonbonding shifts toward lower binding energy and that of bonding O 2p orbitals shifts toward higher binding energy. The photoelectrocatalytic(PEC) oxidation of humic acid(HA) was investigated in terms of TOC. The PEC oxidation efficiency of Ti/Au TiO 2 mesh with optimal content of gold is higher than that of Ti/TiO 2 mesh. It is suggested that the recombination of electrons and holes is hindered owing to gold deposition. The investigation shows that PEC oxidation is a convenient way to mineralize organic matter for water treatment.
文摘Fibre-reinforced polymer (FRP) composites were widely utilized in civil engineering structures as the retrofit of reinforced concrete (RC) columns. To design FRP jackets safely and economically, the behaviour of such columns should be predicted first. This paper is concerned with the analysis and behaviour of FRP-confined RC circular and rectangular short col- umns subjected to eccentric loading. A simple design-oriented stress-strain model for FRP-confined concrete in a section analysis was first proposed. The accuracy was then proved by two test data. Following that, a parametric study including amount of FRP confinement, FRP strain capacity, unconfined concrete strength and shape of column section is provided. Some conclusions were obtained at the end of the paper. The work here will provide a comprehensive understanding of the behaviour of FRP-confined concrete columns. The simplicity of the model also enables a simple equivalent stress block to be developed for direct use in practical design.
基金supported by the Hong Kong Research Grants Council (Poly U5211/09E) and PolyU internal grant (G-U593)supported by the National Key Basic Research Development Program of China (Grant Nos.2010CB428503 and 2011CB403406)
文摘The relationship between the emission of ozone precursors and the chemical production of tropospheric ozone （03） in the Pearl River Delta Region （PRD） was studied using numerical simulation. The aim of this study was to examine the volatile organic compound （VOC）- or nitrogen oxide （NO~ =NO＋NO2）- limited conditions at present and when surface temperature is increasing due to global warming, thus to make recommendations for future ozone abatement policies for the PRD region. The model used for this application is the U.S. Environmental Protection Agency＇s （EPA＇s） third-generation air-quality modeling system; it consists of the mesoscale meteorological model MM5 and the chemical transport model named Community Multi-scale Air Quality （CMAQ）. A series of sensitivity tests were conducted to assess the influence of VOC and NO~ variations on ozone production. Tropical cyclone was shown to be one of the important synoptic weather patterns leading to ozone pollution. The simulations were based on a tropical- cyclone-related episode that occurred during 14-16 September 2004. The results show that, in the future, the control strategy for emissions should be tightened. To reduce the current level of ozone to meet the Hong Kong Environmental Protection Department （EPD） air-quality objective （hourly average of 120 ppb）, emphasis should be put on restricting the increase of NOx emissions. Furthermore, for a wide range of possible changes in precursor emissions, temperature increase will increase the ozone peak in the PRD region; the areas affected by photochemical smog are growing wider, but the locations of the ozone plume are rather invariant.
基金supported by the National Key Basic Research Program of the Ministry of Science and Technology of China(Grant No.2010CB429001)the Special Fund of State Key Laboratory of China(Grant No.2011585812)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.2011B05614)the 111 Project of the Ministry of Educationthe State Administration of Foreign Experts Affairs,China(Grant No.B12032)
文摘This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation （LES） model is developed to simulate the buoyant jet in a stagnant ambient and JONSWAP random waves. By comparison of velocity and concentration fields, it is found that the buoyant jet exhibits faster decay of centerline velocity, wider lateral spreading and larger initial dilution under the wave effect, indicating that wave dynamics improves the jet entrainment and mixing in the near field, and subsequently mitigate the jet impacts in the far field. The effect of buoyancy force on the jet behaviours in the random waves is also numerically investigated. The results show that the wave effect on the jet entrainment and mixing is considerably weakened under the existence of buoyancy force, resulting in a slower decay rate of centerline velocity and a narrower jet width for the jet with initial buoyancy.
