饱和黏土不排水剪切的热破坏  

Thermal failure for saturated clay under undrained condition

作　　者：姚仰平[1] 万征[1] 杨一帆[1] 牛雷[1] 

机构地区：[1]北京航空航天大学交通科学与工程学院,北京100191

出　　处：《岩土力学》2011年第9期2561-2569,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.50879001;No.10872016;No.11072016)

摘　　要：试验资料表明:饱和黏土在不排水常载升温条件下会产生很大的变形并最终可发生热破坏现象,因此,升温也成为一种加载方式。基于姚仰平等提出的热UH临界状态模型,推导了受温度影响的热不排水抗剪强度表达式,对不同超固结度饱和黏土在升温下的不排水抗剪强度模拟与试验结果对比表明:所提公式能够合理反映试验资料中受温度影响的不排水抗剪强度变化规律。利用热UH模型对不排水常载-升温过程进行了模拟,模拟结果表明,热UH模型可合理地反映不排水常载-升温条件下饱和黏土的应力-应变关系以及强度变化规律。针对能影响热破坏过程的几种因素如升温初始时的偏应力比、升温幅度、超固结度以及先期固结压力等进行了讨论分析,得到了各因素对于饱和黏土不排水剪切下的应力-应变关系及强度特性的影响规律。A large deformation would be produced and failure occurs for saturated clay under undrained heating condition at a constant total nonisotropic stress state revealed by test data.Heating should be thought as another loading way.Firstly,an expression of undrained shear strength considering thermal effect is obtained based on the thermal unified hardening（UH） critical state model proposed by Yao et al.Comparison between simulation and test data about undrained shear strength under heating condition for overconsolidated clay with different over consolidation ratios（OCRs） has shown that the variation regularity of undrained shear strength considering thermal effect can be described using the proposed formula.The process at a constant total nonisotropic stress state with heating under undrained condition is simulated using thermal UH model.The prediction result has shown that the thermal UH model can be applied to describe stress-strain relationship and variation regularity of shear strength under undrained condition for saturated clay reasonably.Finally,the value of deviatoric stress ratio at initial time for heating,the magnitude of heating,OCR and preconsolidation pressure are all discussed and analyzed.The regularities of stress-strain relationship and property of strength for saturated clay under undrained condition affected by above factors are obtained.

关 键 词：升温 超固结黏土 不排水 临界状态 强度 

分 类 号：TU443[建筑科学—岩土工程]