西宁地区原状黄土三轴试验及数值模拟

Triaxial test and numerical simulation of undisturbed loess in Xining area

在数值模拟中合理选取土的本构关系与模型参数,对模拟的合理性和可靠性十分重要。为研究西宁地区LNG储存罐基础原状黄土数值模拟中本构关系与模型参数选取的合理性,采用三轴试验与数值模拟相结合的方法,分别对Mohr-Coulomb、土体硬化及修正剑桥模型3种本构模型进行分析研究。结果表明:西宁地区原状黄土采用土体硬化双曲线本构模型与试验结果吻合程度较高,其模量随应变增大而减小的特征与原状黄土实际力学特征相似,土体硬化本构模型更加符合土体的实际力学特性。

It is very important to select soil constitutive relation and model parameters in finite element simulation.In order to study the rationality of constitutive relation and model parameters selection in the numerical simulation of undisturbed loess on the basis of LNG storage tanks in Xining area,three constitutive models,Mohr-Coulomb,hardening soil model and modified Cam-Clay model,are studies and analyzed respectively by the method of triaxial test and numerical simulation.The results reveal that the hyperbolic constitutive model of hardened soil in Xining area is in good agreement with the test results;furthermore,its modulus decreases with the increase of strain,which is similar to the actual mechanical characteristics of undisturbed loess.In conclusion,the constitutive model of hardening soil is more consistent with the actual mechanical characteristics of soil.