CPTU贯入数值模拟及锥尖阻力系数影响因素研究

Numerical Simulation of CPTU Penetration and Research on Influencing Factors of Cone Tip Resistance Coefficient

孔压静力触探(Piezocone Penetration Test,简称CPTU)是当前应用较为广泛的原位测试方法之一。为了研究CPTU在粘性土贯入过程中,土体刚度、侧压系数、固结比、摩擦系数对锥尖阻力系数(N_(c))的影响。本文运用耦合欧拉-拉格朗日(Couple Eurian Lagrangian,简称“CEL”)大变形有限元计算技术,采用自编修正剑桥模型(Modify Cam-clay,简称MCC),模拟CPTU的贯入过程。在验证网格密度、贯入速度对模拟结果精度影响的基础上,与公开文献中标准罐试验数据进行了验证。分析了CPTU在贯入一定深度稳定状态下土体刚度、侧压系数、固结比和摩擦系数对Nc的影响。结果表明:Nc随着土体刚度、摩擦系数的增加而增加,随着地应力因数的增加而降低,标准化锥尖阻力随着超固结比的增加而增加。

Piezocone penetration test(CPTU)is one of the most widely used in-situ testing methods.In order to study the influence of soil stiffness,lateral pressure coefficient,consolidation ratio and friction coefficient on the cone tip resistance coefficient during the penetration process of CPTU in cohesive soil,the coupled Euler-Lagrangian(CEL)large deformation finite element calculation technology is used,and the modified Cam-clay(MCC)model is used to simulate the penetration process of CPTU.On the basis of verifying the influence of grid density and penetration velocity on the accuracy of the simulation results,it is verified with the standard tank test data in the open literature.The effects of soil stiffness,lateral pressure coefficient,consolidation ratio and friction coefficient on the cone tip resistance coefficien(N_(c))are analyzed under the stable state of CPTU penetration at a certain depth.The analysis results show that Ncincreases with the increase of soil stiffness and friction coefficient,and decreases with the increase of the in-situ stress factor,and the normalized cone tip resistance increases with the increase of the overconsolidation ratio.