摘要
随着三维数值极限分析得到日益关注,亟需发展适用于岩土常规三轴应力状态的Drucker-Prager(DP)准则。当前尚无适用于岩土常规三轴条件的DP准则的精确解,而是使用近似的等面积圆DP-3_(1)准则,该准则偏安全。基于岩土三剪能量准则,推导了该准则最高点(即该准则与摩尔-库仑准则的切点)对应的罗德角的表达式,进而通过最高点建立了岩土常规三轴DP-3_(2)准则,并将其应用于常规三轴条件下土体的极限荷载计算与边坡稳定性分析。研究表明:DP-3_(2)准则计算的常规三轴下土体极限荷载为实测值的87%~97%,DP-3_(2)准则与DP-3_(1)准则计算的极限荷载之比可达1.19,且随着围压减小、黏聚力c增大或者内摩擦角φ增大,二者计算结果的差异增大;DP-3_(2)准则计算的土质边坡稳定安全系数为DP-3_(1)准则计算结果的1.01~1.04倍,且二者差异随着坡度增大而增大。这些结果表明DP-3_(2)准则适用于岩土常规三轴应力状态下的数值极限分析。
With the increasing attention paid to three-dimensional numerical limit analysis,there is an urgent need to develop a new Drucker-Prager(DP)criterion suitable for geomaterials under conventional triaxial stress condition.Yet,an exact DP criterion for geomaterials under conventional triaxial stress condition does not exist.Instead,an approximate equal-area-circle DP-31 criterion has been used traditionally,which is relatively safe.This study developed a new DP-32 criterion for geomaterials under conventional triaxial stress condition based on the tri-shear energy yield criterion.The theoretical formulation was derived to determine the highest point of the criterion(i.e.,the tangent point between the criterion and the Mohr-Coulomb criterion).Then,the conventional triaxial DP-32 criterion was established through the highest point.Thereafter,this new criterion was used to determine the ultimate load of soil under conventional triaxial condition and slope stability analysis.The ultimate load of soil under conventional triaxial condition determined by the DP-32 criterion was found to be about 87%–97%of the measured value.Moreover,the maximum ratio of ultimate load computed by the DP-32 criterion to the DP-31 criterion was 1.19,and it increased with decreasing confining pressure,increasing cohesion c,or increasing internal friction anglej.The factor of safety(FOS)of soil slopes determined by the DP-32 criterion was approximately 1.01–1.04 times that determined by the DP-31 criterion.Furthermore,the difference increased at larger slope angles.These results suggest that the DP-32 criterion is suitable for numerical limit analysis of geomaterials under conventional triaxial stress condition.
作者
冯嵩
郑颖人
高红
FENG Song;ZHENG Ying-ren;GAO Hong(Sustainable Energy and Environment Thrust,Function Hub,the Hong Kong University of Science and Technology(Guangzhou),Guangzhou,Guangdong 511453,China;Department of Military Installations,Army Logistics Academy of PLA,Chongqing 400041,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第10期2919-2928,共10页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52178320)。
关键词
数值极限分析
强度准则
有限元法
边坡稳定性
numerical limit analysis
strength criterion
finite element method
slope stability
