利用旁压试验的砂土初始状态反演分析

讨论了砂土旁压试验的反分析问题。建议利用旁压试验实测数据反演确定土体的初始状态而非材料参数，材料参数可以通过实验室常规试验确定。主要利用了新型的亚塑性本构模型参数不受土体状态影响的特点。主要内容包括：建立有限元数值模型，利用文献中的试验数据确定了特定砂土的材料参数；通过模拟砂土的实验室旁压试验，验证了数值模型；通过改变土体初始应力状态和相对密实度进行数值计算，并利用数值计算成果，建立了可适用于砂土初始状态反演分析的实测旁压荷载和土体中应力与相对密度的数学关系。

Back analysis of initial state of sand from pressuremeter test

The back analysis of pressuremeter test of sand is discussed.The measured data of pressuremeter test are used for inversive determination of the in situ state of the soil instead of the material parameters.The material parameters can be determined from the conventional laboratory tests.The characteristics of new hypoplastic model which is independent of soil state are used.The main contents include: establishment of the numerical model based on the finite element method for the back analysis,and determination of the material parameters for a specific sand using the related data from the literature;verification of the numerical model by simulating laboratory pressuremeter test;further numerical study carried out by changing the initial stress and relative density of soil,and establishment of relation between the measured pressuremeter,the stress and the relative density of sand based on the numerical results,which can be used for the back analysis.