作者：乔响平；姚晓亮；齐吉琳；张泽；慕青松

第一作者单位：兰州大学土木工程与力学学院；兰州大学西部灾害与环境力学教育部重点实验室

摘要：作为冻土的一个重要力学参数,塑性屈服应力受诸多因素制约,如冻土温度、含水率和受力状态等。为探究蠕变对冻土塑性屈服应力的影响,引入融土的一维蠕变模型量化研究冻土蠕变对其塑性屈服应力的影响,以青藏铁路沿线具有代表性的黏土作为研究对象,进行了不同时长的蠕变试验和K0逐级加载试验。试验结果表明,针对融土提出的一维蠕变模型在描述冻土蠕变-卸载-加载过程中有很好的适用性。通过试验对比分析和计算结果得知,塑性屈服应力是初始塑性屈服应力、压缩系数和回弹系数的函数,且其对数与蠕变应变(时间)呈线性关系,这一量化关系能够较好地描述冻土塑性屈服应力与蠕变应变(时间)的发展规律。

Abstract：Plastic yield stress is an important mechanic parameters of frozen soil.It is affected by a number of factors, such as frozen soil temperature, moisture content and stress.In order to quantitative the effect of creep on plastic yield stress of frozen soil, a one-dimensional creep model is proposed.A typical clay obtained along the Qinghai-Tibet highway is taken as an example.For each specimen, creep experiment for different durations was conducted at first, and then step loadings under K0 condition were applied.The results show that the applicability of the model directed at thawed soil was verified feasibility during the process of creep-unloading-loading.The comparison between test and calculation result reveals that plastic yield stress is a function of initial plastic yield stress, compression and unloading index.The logarithm of plastic yield stress is linearly related with creep strain (time) .This quantitative relations describe well in relations between frozen soil plastic yield stress and creep strain (time) .

基金：国家自然科学基金资助项目(41671061,41501084,141401087)；冻土工程国家重点实验室自主研究课题(SKLFSE-ZT-28)；北京市属高等学校高层次人才引进与培养计划项目(CIT&TCD20150101)；

关键词：蠕变;冻土;冻土蠕变模型;塑性屈服应力;

DOI：10.16186/j.cnki.1673-9787.2017.05.020

分类号：P642.14