原状软黏土主应力轴动态旋转试验研究

发布时间：2018-05-26 03:41

本文选题：主应力轴动态旋转 + 原状软黏土　；参考：《中南大学学报(自然科学版)》2014年03期

【摘要】：利用浙江大学5 Hz空心圆柱扭剪仪,通过轴力和扭矩的耦合,模拟波浪荷载下主应力轴动态旋转的应力路径,对杭州原状软黏土的孔压累积、应变发展及模量衰减等动力特性进行研究,研究频率、循环应力比的影响,并与动三轴试验相比较。通过对试验数据的回归分析,给出主应力轴动态旋转下原状软黏土模量衰减的经验公式。结果表明:频率越低或循环应力比越大,孔压累积、应变发展及模量衰减的速率越快,破坏所需要的循环次数越少;虽然各应变分量开展程度不同,但应变曲线均在同一循环次数时出现拐点;循环加载过程中,压缩模量和剪切模量的衰减规律基本相同,但压缩模量衰减速率稍快于剪切模量。与动三轴试验结果相比,主应力轴连续旋转试验中土体模量衰减规律基本不变,但衰减速度更快,试样破坏所需的循环次数明显减少,因此,建议实际工程应用时要考虑主应力轴旋转的影响。
[Abstract]:By using the 5 Hz hollow cylindrical torsional shear apparatus of Zhejiang University, the dynamic rotation stress path of the principal stress axis under wave load was simulated by coupling the axial force and torque, and the pore pressure accumulation of the undisturbed soft clay in Hangzhou was studied. The dynamic characteristics such as strain development and modulus attenuation are studied. The effects of frequency and cyclic stress ratio are studied and compared with the dynamic triaxial test. Based on the regression analysis of experimental data, the empirical formula of modulus attenuation of undisturbed soft clay under dynamic rotation of principal stress axis is given. The results show that the lower the frequency or the greater the ratio of cyclic stress, the faster the pore pressure accumulates, the faster the strain development and modulus decay, the less the cycle number is required for failure, although the different strain components develop differently. During cyclic loading, the attenuation law of compression modulus and shear modulus is basically the same, but the attenuation rate of compression modulus is a little faster than that of shear modulus. Compared with the dynamic triaxial test results, the modulus attenuation law of soil in the continuous rotation test of the principal stress axis is basically unchanged, but the attenuation speed is faster, and the cycle times required for the specimen failure are obviously reduced. It is suggested that the effect of rotation of principal stress axis should be taken into account in practical engineering application.
【作者单位】：浙江大学滨海和城市岩土工程研究中心;浙江大学软弱土与环境土工教育部重点实验室;
【基金】：国家自然科学基金资助项目(50778162,51178422)
【分类号】：TU411

【参考文献】