高压力作用下深部粘土冻结后卸载应力路径的力学性质研究  

Study of the Mechanical Properties of Frozen Deep-Buried Clay under High Pressures in Unloaded State

作　　者：田怀植[1] 王大雁[1] 马巍[1] 关辉[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2010年第2期351-357,共7页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金重点项目(50534040);冻土工程国家重点实验室自主研究项目(SKLFSE-ZY-02-3);国家自然科学基金创新群体项目(40821001);中国科学院知识创新工程重要方向性项目(KZCX2-YW-QN307)资助

摘　　要：利用等压固结的方法将深部粘土在室内恢复至其原始地压状态,研究高压力作用下形成冻土在径向卸载状态下的力学行为、强度特征.结果表明:经等压固结再冻结的粘土试样在整个径向卸载过程中应力-应变行为属于典型的粘-塑性破坏类型,其三轴屈服强度与初始围压无关,而随冻土温度的降低呈现线性增大的趋势.卸载过程中的应力-应变行为符合修正后的Duncan-Chang模型.Based on simulation mechanical experiments of laboratory-prepared frozen specimens of clay from deep alluvium,the behaviors of stress-strain of the frozen clay were studied,the radial unloading shear tests under different temperatures and confining pressures were done,and a linear regression model of the behavior of stress-strain was established. The testing process was as follows：Firstly,soil specimens were isotropically consolidated in high pressure state,then frozen rapidly and controlled to the test temperature quickly; secondly,in order to ensure the specimens being frozen adequately,the specimens were rested for more than 33.5 h; finally,a constant axial pressure was applied to the radial unloading specimen. The results indicate that after isotropic consolidation and frozen,the stress-strain behavior of the specimen belongs to typically viscoplastic damage type during the whole radial unloading process. The triaxial yield strength is uncorrelated with initial confining pressure,but increases linearly with temperature decreasing. The behavior of radial unloading stress-strain conforms to the revised Duncan-Chang Model.

关 键 词：深部粘土 高压力 等压固结 人工冻结 径向卸载 应力-应变行为 

分 类 号：P642.14[天文地球—工程地质学]