基于状态参数的砂土非线性弹性模型研究  

STUDY OF NONLINEAR ELASTIC MODEL OF SAND BASED ON STATE PARAMETERS

作　　者：陈成[1] 周正明[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071

出　　处：《岩石力学与工程学报》2013年第2期369-376,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2010CB732101)

摘　　要：砂土的密实度和有效围压显著地影响着它的力学变形特性。为了反映这2个因素的影响效应,对沈珠江基于初应变法提出的三参数(压缩模量K0、杨氏模量、体变系数)非线性弹性模型进行修正。首先建立一种可以有效地反映初始状态影响的K0压缩曲线描述模式。其次,为了反映密实度和有效围压对排水三轴试验中剪切曲线的影响,基于状态参数定义"虚拟峰值偏应力"这一变量,并给出一个新的剪切曲线描述模式。另外,为了描述砂土的变形特性,引入剪胀方程。该修正模型数学描述简单,仅有10个材料参数,且各参数均容易确定。最后,利用该修正模型对排水、不排水条件下的三轴试验进行模拟,模型的计算结果与实测结果吻合较好,表明该修正模型可以较准确地描述砂土的物理状态变化对其力学与变形特性的影响,初步验证模型的合理性。Mechanical and deformational characteristics of sands are significantly affected by density and effective confining pressure. In order to reflect the effect of the two factors, the nonlinear elastic model with three-parameters （compression modulus K0, Young＇s modulus and coefficient of volumetric deformation）, which was proposed by SHEN Zhujiang based on the initial strain method was modified. Firstly, a description mode of K0 compression curve was established, which could describe the effect of initial state effectively. Then, the variable of virtual peak deviator stress was defined based on state parameter： and a new description mode of shear curve was proposed so as to reflect the effect of density and effective confining pressure. In addition, dilatancy equation was also introduced to describe deformational characteristics of sand. Mathematical description of the modified model is simple, and only ten parameters are involved and easy to identify. Finally, the modified model was used to simulate drained and undrained triaxial tests. A good agreement between computed results and measured results show that the modified model can describe the effect of variation of state parameter on the mechanical and deformation characteristics of sands accurately, so as to verify the rationality of the model primarily.

关 键 词：土力学 砂土 状态参数 压缩 应变软化 剪胀性 非线性弹性 

分 类 号：TU47[建筑科学—结构工程]