The objective of this study is to develop an analytical methodology to evaluate the effectiveness of vibro stone column (S.C.) and dynamic compaction (D.C.) techniques supplemented with wick drains to densify and miti...The objective of this study is to develop an analytical methodology to evaluate the effectiveness of vibro stone column (S.C.) and dynamic compaction (D.C.) techniques supplemented with wick drains to densify and mitigate liquefaction in saturated sands and non-plastic silty soils. It includes the following: (i) develop numerical models to simulate and analyze soil densitication during S.C. installation and D.C. process, and (ii) identify parameters controlling post-improvement soil density in both cases, and (iii) develop design guidelines for densification of silty soils using the above techniques. An analytical procedure was developed and used to simulate soil response during S.C. and D.C. installations, and the results were compared with available case history data. Important construction design parameters and soil properties that affect the effectiveness of these techniques, and construction design choices suitable for sands and non-plastic silty soils were identified. The methodology is expected to advance the use of S.C. and D.C. in silty soils reducing the reliance on expensive field trials as a design tool. The ultimate outcome of this research will be design charts and design guidelines for using composite stone columns and composite dynamic compaction techniques in liquefaction mitigation of saturated silty soils.展开更多
The complex tunnelling constructive environment in urban area in similar green field situations is faced through analytical evaluations in order to control the design calculation process and subsequently manage the in...The complex tunnelling constructive environment in urban area in similar green field situations is faced through analytical evaluations in order to control the design calculation process and subsequently manage the interventions techniques with the aim of totally reducing the typical settlements trough above the tunnel either during the construction stage or during the serviceability stage. Recently, the author has proposed an operative and mathematical method by an opportune choice of tensioned anchors to control the tunnel lining settlements. In order to completely eliminate the remainder typical soft soil trough which is normal to the line of the tunnel, it is here proposed to use and properly calculate the interventions of stone columns by the SAVE （silent, advanced, vibration-erasing） Compozer method, in combination with the anchorages.展开更多
Stone column is one of the soil stabilizing methods that is used to increase bearing capacity and decrease the settlement of soft soils.Reinforced and unreinforced granular blankets are now being utilized to overcome ...Stone column is one of the soil stabilizing methods that is used to increase bearing capacity and decrease the settlement of soft soils.Reinforced and unreinforced granular blankets are now being utilized to overcome the problems of soft soils.In this research,the bearing capacity of stone columns,granular blanket,and a combination of both methods in reinforced and unreinforced modes were studied using scaled physical models.Results show that using granular blanket,stone column,and combination of both improves bearing capacity of soft soils.Using geogrid as the reinforcement of granular blankets and geotextile as stone-column encasement increases the efficiency of granular blankets and stone columns significantly.Additionally,in the case of using geotextile around the stone column,the stress concentration ratio of the stone column will increase as well as its rigidity and bearing capacity.展开更多
The shaking table model test was conducted to investigate earthquake resistant behavior of stone columns under the intensity of an earthquake resistance of buildings is VIII. The test results show that when accelerati...The shaking table model test was conducted to investigate earthquake resistant behavior of stone columns under the intensity of an earthquake resistance of buildings is VIII. The test results show that when acceleration is less than 0.20 g, composite foundation is not liquefied, settlement is also small and pile dislocation is not observed; when acceleration is 0.3g, ground outside embankment＇s slope toe is liquefied and ground within stone column composite foundation is not. It is suggesting that reinforcement scale of stone column foundation should be widened properly. The designed stone column composite foundation meets the requirements for seismic resistance.展开更多
The recently developed elasto-viscoplastic Creep-SCLAY1S model has been used in conjunction with PLAXIS 2D to investigate the effectiveness of vibro-replacement in a creep-prone clay. The Creep-SCLAY1S model accounts ...The recently developed elasto-viscoplastic Creep-SCLAY1S model has been used in conjunction with PLAXIS 2D to investigate the effectiveness of vibro-replacement in a creep-prone clay. The Creep-SCLAY1S model accounts for anisotropy, bonding, and destructuration, and uses the concept of a constant rate of viscoplastic multiplier to calculate creep strain rate. A comparison of settlement improvement factors with and without creep indicates that ‘total’ settlement improvement factors （primary plus creep） are lower than their ‘primary’ counterparts （primary settlement only）. The lowest settlement improvement factors arise for analyses incorporating the effect of bonding and destructuration. Examination of the variations of vertical stress with time and depth has indicated that vertical stress is transferred from the soil to the column as the soil creeps. This results in additional column yielding. In addition, the radial and hoop stresses in the soil are lower for the ‘creep’ case. The reduced radial stresses lead to additional column bulging and hence more settlement, whereas the hoop stress reductions appear to be a secondary effect, caused by additional plastic deformation for the ‘creep’ case.展开更多
The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the w...The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance （CRR）-shear wave velocity （V）-void ratio （e） of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V of soil is raised high enough （i.e., no less than the critical velocity） to resist the given earthquake loading according to the CRR-V relationship, and then this requirement is transferred to the control of target void ratio （i.e., the critical e） according to the V-e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.展开更多
The utilization of stone columns has emerged as a popular ground improvement strategy,whereas the drainage performance can be adversely hampered by clogging effect.Despite the ample progress of calculation methods for...The utilization of stone columns has emerged as a popular ground improvement strategy,whereas the drainage performance can be adversely hampered by clogging effect.Despite the ample progress of calculation methods for the consolidation of stone column-improved ground,theoretical investigations into the clogging effect have not been thoroughly explored.Furthermore,it is imperative to involve the column consolidation deformation to mitigate computational error on the consolidation of composite ground with high replacement ratios.In this context,an analytical model accounting for the initial clogging and coupled time and depth-dependent clogging of stone columns is established.Then,the resulting governing equations and analytical solutions are obtained under a new flow continuity relationship to incorporate column consolidation deformation.The accuracy and reliability of the proposed model are illustrated by degradation analysis and case studies with good agreements.Subsequently,the computed results of the current study are juxtaposed against the existing models,and an in-depth assessment of the impacts of several crucial parameters on the consolidation behavior is conducted.The results reveal that ignoring column consolidation deformation leads to an overestimate of the consolidation rate,with maximum error reaching up to 16%as the replacement ratio increases.Furthermore,the initial clogging also has a significant influence on the consolidation performance.Additionally,the increment of depth and time-clogging factors a and b will induce a noticeable retardation of the consolidation process,particularly in the later stage.展开更多
The liquefaction analysis procedure conducted at a dam foundation associated with a layer of liquefiablesand is presented. In this case, the effects of the overlying dam and an embedded diaphragm wall onliquefaction p...The liquefaction analysis procedure conducted at a dam foundation associated with a layer of liquefiablesand is presented. In this case, the effects of the overlying dam and an embedded diaphragm wall onliquefaction potential of foundation soils are considered. The analysis follows the stress-based approachwhich compares the earthquake-induced cyclic stresses with the cyclic resistance of the soil, and thecyclic resistance of the sand under complex stress condition is the key issue. Comprehensive laboratorymonotonic and cyclic triaxial tests are conducted to evaluate the static characteristics, dynamic characteristicsand the cyclic resistance against liquefaction of the foundation soils. The distribution of thefactor of safety considering liquefaction is given. It is found that the zones beneath the dam edges andnear the upstream of the diaphragm wall are more susceptible to liquefaction than in free field, whereasthe zone beneath the center of the dam is less susceptible to liquefaction than in free field. According tothe results, the strategies of ground improvement are proposed to mitigate the liquefaction hazards. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
In actual engineering practice,the stress increment within a composite foundation caused by external loads may vary simultaneously with depth and time.In addition,column installation always leads to a decay of soil pe...In actual engineering practice,the stress increment within a composite foundation caused by external loads may vary simultaneously with depth and time.In addition,column installation always leads to a decay of soil permeability towards the column.However,almost none of the consolidation theories for composite foundation comprehensively consider these factors until now.For this reason,a stress increment due to external loads changing simultaneously with time and depth was incorporated into the analysis,and three possible variation patterns of soil's horizontal permeability coefficient were considered to account for the detrimental influence of column installation.These three patterns included a constant distribution pattern(Pattern I),a linear distribution pattern(Pattern II),and a parabolic distribution pattern(Pattern III).Solutions were obtained for the average excess pore water pressures and the average degree of consolidation respectively.Then several special cases were discussed in detail based on the general solution obtained.Finally,comparisons were made,and the results show that the present solution is the most general rigorous solution in the literature,and it can be broken down into a number of previous solutions.The consolidation rate is accelerated with the increase in the value of the top to the bottom stress ratio.The consolidation rate calculated by the solution for Pattern I is less than that for Pattern II,which in turn is less than that for Pattern III.展开更多
This study investigates the ground and structural response of adjacent raft foundations induced by largescale surcharge by ore in soft soil areas through a 130g centrifuge modeling test with an innovative layered load...This study investigates the ground and structural response of adjacent raft foundations induced by largescale surcharge by ore in soft soil areas through a 130g centrifuge modeling test with an innovative layered loading device.The prototype of the test is a coastal iron ore yard with a natural foundation of deep soft soil.Therefore,it is necessary to adopt some measures to reduce the influence of the large-scale surcharge on the adjacent raft foundation,such as installing stone columns for foundation treatment.Under an acceleration of 130 g,the model conducts similar simulations of iron ore,stone columns,and raft foundation structures.The tested soil mass has dimensions of 900 mm×700 mm×300 mm(lengthwidthdepth),which is remodeled from the soil extracted from the drilling holes.The test conditions are consistent with the actual engineering conditions and the effects of four-level loading conditions on the composite foundation of stone columns,unreinforced zone,and raft foundations are studied.An automatic layer-by-layer loading device was innovatively developed to simulate the loading process of actual engineering more realistically.The composite foundation of stone columns had a large settlement after the loading,forming an obvious settlement trough and causing the surface of the unreinforced zone to rise.The 12 m surcharge loading causes a horizontal displacement of 13.19 cm and a vertical settlement of 1.37 m in the raft foundation.The stone columns located on both sides of the unreinforced zone suffered significant shear damage at the sand-mud interface.Due to the reinforcement effect of stone columns,the sand layer below the top of the stone columns moves less.Meanwhile,the horizontal earth pressure in the raft foundation zone increases slowly.The stone columns will form new drainage channels and accelerate the dissipation of excess pore pressure.展开更多
Weak soils,such as soft clay and loose sand,have a poor bearing capacity,making them incapable of bearing the load of superstructures that will be imposed on them.As a result,engineers must have a solution to th...Weak soils,such as soft clay and loose sand,have a poor bearing capacity,making them incapable of bearing the load of superstructures that will be imposed on them.As a result,engineers must have a solution to the issue of poor bearing capacity in weak soils before embanking into building on them.This paper reviewed the use of stone columns,piled rafts,and geogrids for improving the bearing capability of weak soils.Important findings from recent research are also discussed.From the review of the previous researcher’s findings,it was found that modelling approaches such as physical modelling(full scale,centrifuge,laboratory scale)and numerical modelling are used to study bearing capacity improvement.展开更多
In response to the existing consolidation theory for stone column composite foundations which cannot consider the time-dependent loading and the well resistance effect of stone columns under time-dependent boundaries,...In response to the existing consolidation theory for stone column composite foundations which cannot consider the time-dependent loading and the well resistance effect of stone columns under time-dependent boundaries,a consolidation model that can reflect these characteristics is developed in this study,and the corresponding analytical solutions are obtained under permeable top surface with permeable bottom surface(PTPB)and permeable top surface with impermeable bottom surface(PTIB),respectively.In addition,the reliability of the proposed solutions is verified by comparing them with existing analytical solutions.Extensive calculations are then performed by the proposed solutions to analyze the consolidation behaviors of stone column composite foundations under time-dependent boundaries,the results show that the interface parameters have a large effect on the distribution of excess pore water pressure(EPWP)along the depth;for projects with longer construction time,the permeability of the top and bottom surfaces of the composite foundation has a smaller effect on the average consolidation rate.Finally,the proposed solution is applied to the settlement calculation in an actual engineering project,and the theoretical results show a general agreement with the measured data by considering the influence of the interface parameters.展开更多
基金Federal Highway Administration(FHWA)Under Grant No.DTFH61-98-C-0094
文摘The objective of this study is to develop an analytical methodology to evaluate the effectiveness of vibro stone column (S.C.) and dynamic compaction (D.C.) techniques supplemented with wick drains to densify and mitigate liquefaction in saturated sands and non-plastic silty soils. It includes the following: (i) develop numerical models to simulate and analyze soil densitication during S.C. installation and D.C. process, and (ii) identify parameters controlling post-improvement soil density in both cases, and (iii) develop design guidelines for densification of silty soils using the above techniques. An analytical procedure was developed and used to simulate soil response during S.C. and D.C. installations, and the results were compared with available case history data. Important construction design parameters and soil properties that affect the effectiveness of these techniques, and construction design choices suitable for sands and non-plastic silty soils were identified. The methodology is expected to advance the use of S.C. and D.C. in silty soils reducing the reliance on expensive field trials as a design tool. The ultimate outcome of this research will be design charts and design guidelines for using composite stone columns and composite dynamic compaction techniques in liquefaction mitigation of saturated silty soils.
文摘The complex tunnelling constructive environment in urban area in similar green field situations is faced through analytical evaluations in order to control the design calculation process and subsequently manage the interventions techniques with the aim of totally reducing the typical settlements trough above the tunnel either during the construction stage or during the serviceability stage. Recently, the author has proposed an operative and mathematical method by an opportune choice of tensioned anchors to control the tunnel lining settlements. In order to completely eliminate the remainder typical soft soil trough which is normal to the line of the tunnel, it is here proposed to use and properly calculate the interventions of stone columns by the SAVE （silent, advanced, vibration-erasing） Compozer method, in combination with the anchorages.
文摘Stone column is one of the soil stabilizing methods that is used to increase bearing capacity and decrease the settlement of soft soils.Reinforced and unreinforced granular blankets are now being utilized to overcome the problems of soft soils.In this research,the bearing capacity of stone columns,granular blanket,and a combination of both methods in reinforced and unreinforced modes were studied using scaled physical models.Results show that using granular blanket,stone column,and combination of both improves bearing capacity of soft soils.Using geogrid as the reinforcement of granular blankets and geotextile as stone-column encasement increases the efficiency of granular blankets and stone columns significantly.Additionally,in the case of using geotextile around the stone column,the stress concentration ratio of the stone column will increase as well as its rigidity and bearing capacity.
文摘The shaking table model test was conducted to investigate earthquake resistant behavior of stone columns under the intensity of an earthquake resistance of buildings is VIII. The test results show that when acceleration is less than 0.20 g, composite foundation is not liquefied, settlement is also small and pile dislocation is not observed; when acceleration is 0.3g, ground outside embankment＇s slope toe is liquefied and ground within stone column composite foundation is not. It is suggesting that reinforcement scale of stone column foundation should be widened properly. The designed stone column composite foundation meets the requirements for seismic resistance.
基金the funding provided by the Irish Research Council(IRC) for the research into stone column behaviour in creep-prone soilspart of CREEP(Creep of Geomaterials,PIAP-GA-2011-286397) project supported by the European Community through the programme Marie Curie Industry-Academia Partnerships and Pathways(IAPP) under the 7th Framework ProgrammeThe support from the BIG(Better Interaction in Geotechnics) project from the Swedish Transport Administration
文摘The recently developed elasto-viscoplastic Creep-SCLAY1S model has been used in conjunction with PLAXIS 2D to investigate the effectiveness of vibro-replacement in a creep-prone clay. The Creep-SCLAY1S model accounts for anisotropy, bonding, and destructuration, and uses the concept of a constant rate of viscoplastic multiplier to calculate creep strain rate. A comparison of settlement improvement factors with and without creep indicates that ‘total’ settlement improvement factors （primary plus creep） are lower than their ‘primary’ counterparts （primary settlement only）. The lowest settlement improvement factors arise for analyses incorporating the effect of bonding and destructuration. Examination of the variations of vertical stress with time and depth has indicated that vertical stress is transferred from the soil to the column as the soil creeps. This results in additional column yielding. In addition, the radial and hoop stresses in the soil are lower for the ‘creep’ case. The reduced radial stresses lead to additional column bulging and hence more settlement, whereas the hoop stress reductions appear to be a secondary effect, caused by additional plastic deformation for the ‘creep’ case.
基金National Natural Science Foundation of China under Grant No.51578501 and No.51127005the Foundation for the Author of National Excellent Doctoral Dissertation of P R China under Grant No.201160+3 种基金the Zhejiang Provincial Natural Science Foundation of China under Grant No.LR15E080001the National Basic Research Program of China(973 Project)under Grant No.2014CB047005the Fundamental Research Funds for the Central Universities under Grant No.2014FZA4016Zhejiang University K.P.Chao’s High Technology Development Foundation(2014)
文摘The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance （CRR）-shear wave velocity （V）-void ratio （e） of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V of soil is raised high enough （i.e., no less than the critical velocity） to resist the given earthquake loading according to the CRR-V relationship, and then this requirement is transferred to the control of target void ratio （i.e., the critical e） according to the V-e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.
基金funding support from the National Natural Science Foundation of China(Grant Nos.52178373 and 51878657).
文摘The utilization of stone columns has emerged as a popular ground improvement strategy,whereas the drainage performance can be adversely hampered by clogging effect.Despite the ample progress of calculation methods for the consolidation of stone column-improved ground,theoretical investigations into the clogging effect have not been thoroughly explored.Furthermore,it is imperative to involve the column consolidation deformation to mitigate computational error on the consolidation of composite ground with high replacement ratios.In this context,an analytical model accounting for the initial clogging and coupled time and depth-dependent clogging of stone columns is established.Then,the resulting governing equations and analytical solutions are obtained under a new flow continuity relationship to incorporate column consolidation deformation.The accuracy and reliability of the proposed model are illustrated by degradation analysis and case studies with good agreements.Subsequently,the computed results of the current study are juxtaposed against the existing models,and an in-depth assessment of the impacts of several crucial parameters on the consolidation behavior is conducted.The results reveal that ignoring column consolidation deformation leads to an overestimate of the consolidation rate,with maximum error reaching up to 16%as the replacement ratio increases.Furthermore,the initial clogging also has a significant influence on the consolidation performance.Additionally,the increment of depth and time-clogging factors a and b will induce a noticeable retardation of the consolidation process,particularly in the later stage.
基金the support from the National Natural Science Foundation of China (No. 51209179)
文摘The liquefaction analysis procedure conducted at a dam foundation associated with a layer of liquefiablesand is presented. In this case, the effects of the overlying dam and an embedded diaphragm wall onliquefaction potential of foundation soils are considered. The analysis follows the stress-based approachwhich compares the earthquake-induced cyclic stresses with the cyclic resistance of the soil, and thecyclic resistance of the sand under complex stress condition is the key issue. Comprehensive laboratorymonotonic and cyclic triaxial tests are conducted to evaluate the static characteristics, dynamic characteristicsand the cyclic resistance against liquefaction of the foundation soils. The distribution of thefactor of safety considering liquefaction is given. It is found that the zones beneath the dam edges andnear the upstream of the diaphragm wall are more susceptible to liquefaction than in free field, whereasthe zone beneath the center of the dam is less susceptible to liquefaction than in free field. According tothe results, the strategies of ground improvement are proposed to mitigate the liquefaction hazards. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
基金Project supported by the National Natural Science Foundation of China(No.51009135)the National Science Foundation for Post-doctoral Scientists of China(No.20100481183)the Science Foundation for Young Scholars of China University of Mining&Technology(No.2009A008)
文摘In actual engineering practice,the stress increment within a composite foundation caused by external loads may vary simultaneously with depth and time.In addition,column installation always leads to a decay of soil permeability towards the column.However,almost none of the consolidation theories for composite foundation comprehensively consider these factors until now.For this reason,a stress increment due to external loads changing simultaneously with time and depth was incorporated into the analysis,and three possible variation patterns of soil's horizontal permeability coefficient were considered to account for the detrimental influence of column installation.These three patterns included a constant distribution pattern(Pattern I),a linear distribution pattern(Pattern II),and a parabolic distribution pattern(Pattern III).Solutions were obtained for the average excess pore water pressures and the average degree of consolidation respectively.Then several special cases were discussed in detail based on the general solution obtained.Finally,comparisons were made,and the results show that the present solution is the most general rigorous solution in the literature,and it can be broken down into a number of previous solutions.The consolidation rate is accelerated with the increase in the value of the top to the bottom stress ratio.The consolidation rate calculated by the solution for Pattern I is less than that for Pattern II,which in turn is less than that for Pattern III.
基金funding support from National Key Research and Development Program of China(Grant No.2021YFF0502200)National Natural Science Foundation of China(Grant Nos.52022070 and 51978516).
文摘This study investigates the ground and structural response of adjacent raft foundations induced by largescale surcharge by ore in soft soil areas through a 130g centrifuge modeling test with an innovative layered loading device.The prototype of the test is a coastal iron ore yard with a natural foundation of deep soft soil.Therefore,it is necessary to adopt some measures to reduce the influence of the large-scale surcharge on the adjacent raft foundation,such as installing stone columns for foundation treatment.Under an acceleration of 130 g,the model conducts similar simulations of iron ore,stone columns,and raft foundation structures.The tested soil mass has dimensions of 900 mm×700 mm×300 mm(lengthwidthdepth),which is remodeled from the soil extracted from the drilling holes.The test conditions are consistent with the actual engineering conditions and the effects of four-level loading conditions on the composite foundation of stone columns,unreinforced zone,and raft foundations are studied.An automatic layer-by-layer loading device was innovatively developed to simulate the loading process of actual engineering more realistically.The composite foundation of stone columns had a large settlement after the loading,forming an obvious settlement trough and causing the surface of the unreinforced zone to rise.The 12 m surcharge loading causes a horizontal displacement of 13.19 cm and a vertical settlement of 1.37 m in the raft foundation.The stone columns located on both sides of the unreinforced zone suffered significant shear damage at the sand-mud interface.Due to the reinforcement effect of stone columns,the sand layer below the top of the stone columns moves less.Meanwhile,the horizontal earth pressure in the raft foundation zone increases slowly.The stone columns will form new drainage channels and accelerate the dissipation of excess pore pressure.
文摘Weak soils,such as soft clay and loose sand,have a poor bearing capacity,making them incapable of bearing the load of superstructures that will be imposed on them.As a result,engineers must have a solution to the issue of poor bearing capacity in weak soils before embanking into building on them.This paper reviewed the use of stone columns,piled rafts,and geogrids for improving the bearing capability of weak soils.Important findings from recent research are also discussed.From the review of the previous researcher’s findings,it was found that modelling approaches such as physical modelling(full scale,centrifuge,laboratory scale)and numerical modelling are used to study bearing capacity improvement.
基金supported by the National Natural Science Foundation of China(Grant No.51878320).
文摘In response to the existing consolidation theory for stone column composite foundations which cannot consider the time-dependent loading and the well resistance effect of stone columns under time-dependent boundaries,a consolidation model that can reflect these characteristics is developed in this study,and the corresponding analytical solutions are obtained under permeable top surface with permeable bottom surface(PTPB)and permeable top surface with impermeable bottom surface(PTIB),respectively.In addition,the reliability of the proposed solutions is verified by comparing them with existing analytical solutions.Extensive calculations are then performed by the proposed solutions to analyze the consolidation behaviors of stone column composite foundations under time-dependent boundaries,the results show that the interface parameters have a large effect on the distribution of excess pore water pressure(EPWP)along the depth;for projects with longer construction time,the permeability of the top and bottom surfaces of the composite foundation has a smaller effect on the average consolidation rate.Finally,the proposed solution is applied to the settlement calculation in an actual engineering project,and the theoretical results show a general agreement with the measured data by considering the influence of the interface parameters.
