河津凝灰岩广义应力松弛特性及数值模拟研究

发布时间：2018-03-13 16:45

本文选题：河津凝灰岩　切入点：本构方程　出处：《岩土力学》2017年04期 　论文类型：期刊论文

【摘要】：在很多地下工程实践中,岩体既不是纯蠕变,也不是纯应力松弛,而是随着时间的增加,应力和应变同时发生变化,表现出时间依存性,导致岩体最终破坏,这种现象用一般的蠕变和应力松弛很难解释清楚。全面系统地阐述了广义应力松弛特性及其工程物理意义,借用非线性Maxwell模型,求解了广义应力松弛条件下可变模量本构方程解析解,特别提出了通过交替荷载速率试验和加、卸载试验,精确求解峰前区域荷载速率依从性系数n_1的新方法。进行了70%和90%应力水平下广义应力松弛试验,并讨论和分析了不同应力水平、不同方向系数下广义应力松弛试验的时间依存性,最后用基于非线性Maxwell模型的可变模量本构方程对70%和90%应力水平下的广义应力松弛试验进行了数值模拟,结果表明,计算和试验结果一致性较好,很好地解释了河津凝灰岩广义应力松弛特性。
[Abstract]:In many underground engineering practices, rock mass is neither pure creep nor pure stress relaxation, but with the increase of time, the stress and strain change simultaneously, showing time dependence, resulting in the ultimate failure of rock mass. It is difficult to explain this phenomenon in terms of general creep and stress relaxation. The generalized stress relaxation characteristics and its engineering physical significance are expounded comprehensively and systematically, and the nonlinear Maxwell model is used. The analytical solution of the constitutive equation of variable modulus under generalized stress relaxation condition is solved. In particular, the alternating load rate test and loading and unloading test are proposed. A new method for accurately solving the load rate compliance coefficient n / 1 in the prepeak region is presented. The generalized stress relaxation tests at the stress levels of 70% and 90% are carried out, and different stress levels are discussed and analyzed. The time dependence of generalized stress relaxation tests under different direction coefficients is studied. Finally, the generalized stress relaxation tests at 70% and 90% stress levels are numerically simulated by using the variable modulus constitutive equation based on nonlinear Maxwell model. The results show that, The calculated results are in good agreement with the experimental results, and the generalized stress relaxation characteristics of Hejin tuff are well explained.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室;重庆文理学院建筑工程学院;东京大学工学系;
【基金】：重庆市基础与前沿研究一般项目(No.cstc2014jcyjA0994) 重庆市教委科学技术项目(No.KJ1711271) 国家自然科学基金面上项目(No.51474040)~~
【分类号】：TU45

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