苇子水水库自第一次蓄水至今,存在较为严重的坝肩渗漏,致使其一直未能正常发挥工程效益。地勘资料显示,大坝坝基渗漏量较大,可能与断层、坝肩部分区域岩石破碎有关。为探明水库主要渗漏部位,指导后续渗漏处理,采用地质勘查与数值模拟相...苇子水水库自第一次蓄水至今,存在较为严重的坝肩渗漏,致使其一直未能正常发挥工程效益。地勘资料显示,大坝坝基渗漏量较大,可能与断层、坝肩部分区域岩石破碎有关。为探明水库主要渗漏部位,指导后续渗漏处理,采用地质勘查与数值模拟相互结合的方法,借助于钻孔压水试验来分析水库严重渗漏的主要部位及范围,并通过坝址区水文地质概念模型和坝址区三维有限元分析模型进行验证。地质勘察结果表明:左坝肩347.954~336.354 m高程存在顺河断层破碎岩,断层岩体渗透系数增大至1×10-3 cm/s和4×10-3 cm/s时,坝基渗流量分别增大为356.60 m 3/d和606.44 m 3/d,且增加部分几乎全来自左岸区域,可见左岸断层岩体是水库主要的渗漏通道,并在此基础上预测了断层条件变化下水库的渗漏量。研究结果可为大坝渗漏后续处理和采取补救措施提供依据。展开更多
Isotropic consolidation test and consolidated-undrained triaxial test were first undertaken to obtain the parameters of the modified cam-clay(MCC)model and the behavior of natural clayey soil.Then,for the first time,n...Isotropic consolidation test and consolidated-undrained triaxial test were first undertaken to obtain the parameters of the modified cam-clay(MCC)model and the behavior of natural clayey soil.Then,for the first time,numerical simulation of the two tests was performed by three-dimensional finite element method(FEM)using ABAQUS program.The consolidated-drained triaxial test was also simulated by FEM and compared with theoretical results of MCC model.Especially,the behaviors of MCC model during unloading and reloading were analyzed in detail by FEM.The analysis and comparison indicate that the MCC model is able to accurately describe many features of the mechanical behavior of the soil in isotropic consolidation test and consolidated-drained triaxial test.And the MCC model can well describe the variation of excess pore water pressure with the development of axial strain in consolidated-undrained triaxial test,but its ability to predict the relationship between axial strain and shear stress is relatively poor.The comparison also shows that FEM solutions of the MCC model are basically identical to the theoretical ones.In addition,Mandel-Cryer effect unable to be discovered by the conventional triaxial test in laboratories was disclosed by FEM.The analysis of unloading-reloading by FEM demonstrates that the MCC model disobeys the law of energy conservation under the cyclic loading condition if the elastic shear modulus is linearly pressure-dependent.展开更多
文摘苇子水水库自第一次蓄水至今,存在较为严重的坝肩渗漏,致使其一直未能正常发挥工程效益。地勘资料显示,大坝坝基渗漏量较大,可能与断层、坝肩部分区域岩石破碎有关。为探明水库主要渗漏部位,指导后续渗漏处理,采用地质勘查与数值模拟相互结合的方法,借助于钻孔压水试验来分析水库严重渗漏的主要部位及范围,并通过坝址区水文地质概念模型和坝址区三维有限元分析模型进行验证。地质勘察结果表明:左坝肩347.954~336.354 m高程存在顺河断层破碎岩,断层岩体渗透系数增大至1×10-3 cm/s和4×10-3 cm/s时,坝基渗流量分别增大为356.60 m 3/d和606.44 m 3/d,且增加部分几乎全来自左岸区域,可见左岸断层岩体是水库主要的渗漏通道,并在此基础上预测了断层条件变化下水库的渗漏量。研究结果可为大坝渗漏后续处理和采取补救措施提供依据。
基金Project(2011J01308) supported by the Natural Science Foundation of Fujian Province,China
文摘Isotropic consolidation test and consolidated-undrained triaxial test were first undertaken to obtain the parameters of the modified cam-clay(MCC)model and the behavior of natural clayey soil.Then,for the first time,numerical simulation of the two tests was performed by three-dimensional finite element method(FEM)using ABAQUS program.The consolidated-drained triaxial test was also simulated by FEM and compared with theoretical results of MCC model.Especially,the behaviors of MCC model during unloading and reloading were analyzed in detail by FEM.The analysis and comparison indicate that the MCC model is able to accurately describe many features of the mechanical behavior of the soil in isotropic consolidation test and consolidated-drained triaxial test.And the MCC model can well describe the variation of excess pore water pressure with the development of axial strain in consolidated-undrained triaxial test,but its ability to predict the relationship between axial strain and shear stress is relatively poor.The comparison also shows that FEM solutions of the MCC model are basically identical to the theoretical ones.In addition,Mandel-Cryer effect unable to be discovered by the conventional triaxial test in laboratories was disclosed by FEM.The analysis of unloading-reloading by FEM demonstrates that the MCC model disobeys the law of energy conservation under the cyclic loading condition if the elastic shear modulus is linearly pressure-dependent.
