应力路径对地表变形特性影响的数值模拟

针对不同环境条件及工程因素对地表变形影响的不同特点，研究了不同应力状态下土的变形特性，得出其影响地表变形的基本规律。通过典型三轴试验对比分析了变形规律，由试验数据空间反演了各应力路径下的本构模型空间，编制相应的模块嵌入有限元程序，模拟了几种不同路径下地表沉降算例，得到了导致地表变形的几个基本规律：①不同的地表变形问题对应的应力路径千差万别，需要用不同的应力路径条件下的本构模型进行分析；②应力路径的影响是不可忽略的，甚至在诸多因素中起主导作用；③数值建模方法建立起来的模型通过权值系列的不同反映应力路径的影响，能较好应用于此类问题的分析；④CTC与TC路径极限体变相差近20 %；⑤CTC路径的剪缩区范围比CTE路径大，两种路径下剪缩体应变值最大相差近17.3 %；CTE路径较CTC路径的剪胀更为明显，剪胀体应变最大相对差值近98 %。

Numerical simulation for influences of stress paths on earth's surface deformation

The effect of stress states on the earth's surface deformation is investigated.With clay selected as test sample,deformation rules obtained by a series of classical triaxial compression test under different stress paths.Based on the tests,a numerical constitutive model under different stress paths is derived by numerical modeling method.Moreover,the constitutive model is set in FEA program to simulate earth's surface deformation under different stress paths.By comparison of the cases,some conclusions are drawn as follows:①effects on the earth's surface deformation under different stress paths are different; ②the influences of stress paths should not be neglected in analysis of the earth's surface deformation; ③the constitutive model by numerical modeling method which can reflect the effects of stress paths by using different weights fits for analysis of the earth's surface deformation; ④the maximum volumetric strain ε_(vmax) of path TC is about 20% lower than path CTC; ⑤Shearing dilatancy field of CTE path is larger than that of CTC path while shearing contraction field is smaller.Maximum relative difference of dilatancy volumetric strain between the two paths is about 17.3% whereas maximum relative difference of contraction volumetric strain is about 98%.