摘要
基于次加载面的砂黏统一本构模型(clay and sand model with subloading surface,简称CASM-S)适用于描述砂土和超固结黏土的力学行为,然而该模型仍沿用线性临界状态描述砂土的应力−孔隙比关系。考虑高应力状态下砂土的压缩特性及其临界状态线在e-lnp平面内的非线性,在CASM-S中引入了描述砂土非线性临界状态线和参考固结线(reference compression curve,简称RCC)的幂函数形式;通过引入参数ξ和λ_(r),修正了CASM-S的屈服面与次加载面函数以描述砂土剪切特性,并利用参考固结线在e-(p/p_(a))^(ξ)(其中e为临界状态下的孔隙比,p为正应力,pa为标准大气压)平面内的线性关系给出了先期固结压力p_(c)0的求解方法。新建本构模型的11个参数均可通过常规土工试验或经验方法确定。基于修正CASM-S的预测结果,对比分析了4种砂土的三轴排水和不排水剪切试验结果,证实了该模型能够有效考虑非线性临界状态线的影响,并能够精确描述饱和砂土在不同孔隙比和围压下的三轴剪切特性。
The unified critical state parameter model(clay and sand model with subloading surface,CASM-S)effectively describes the mechanical behavior of sand and overconsolidated clay.However,the model does not include the nonlinear critical state line of sand.This study investigates the soil’s compression characteristics and its nonlinear critical state line in the e-lnp plane.The CASM-S introduces a power function form of the critical state line and reference compression line(RCC)suitable for sandy soil.With additional parametersx andlr,yield surface and subsequent loading surface functions are proposed to describe the shear characteristics of the sand.The linear relationship of the reference compression curve in the e-(p/p_(a))^(ξ)plane(where e is the void ratio at the critical state,p is the normal stress,and pa is the standard atmospheric pressure)is utilized to propose a method for determining the initial consolidation pressure p_(c)0.All 11 parameters required for this model can be obtained through conventional geotechnical tests or empirical methods.Finally,by comparing the model’s predictions with triaxial drained and undrained shear test results for four types of sand,the refined CASM-S effectively considers the effect of nonlinear critical state line and describes the triaxial shear characteristics of saturated sand under varying void ratios and confining pressures.
作者
富海鹰
钟雨薇
王孝文
吴博涵
袁冉
FU Hai-ying;ZHONG Yu-wei;WANG Xiao-wen;WU Bo-han;YUAN Ran(School of Civil Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 611752,China)
出处
《岩土力学》
北大核心
2025年第6期1788-1798,1810,共12页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52278372,No.52278413)
中国博士后基金(No.2021M702718)。
关键词
临界状态
饱和砂土
次加载面
弹塑性模型
critical state
saturated sand
subloading surface
elasto-plastic model
