【摘要】 为了探明排水条件对高温冻土应力松弛特性的影响,开展了室内松弛试验,研究了排水和不排水情况下高温冻土的应力松弛过程.结果表明:围压对高温冻土的松弛过程影响明显;不排水情况下,围压增大,松弛稳定历时延长,瞬时松弛量增大;松弛过程初期松弛速率受围压影响较大,而后逐渐减弱;排水情况下,松弛过程发展初期的松弛速率略高于不排水情况,但随松弛历时延长这种差别逐渐减小.随着预应变量增大,体积-时间曲线从应变软化状态过渡到应变硬化状态.不排水情况下,松弛过程中的体积变化过程呈先体积收缩后体积膨胀;排水情况下,高温冻土体积在较短历时内迅速收缩,而后基本保持不变.排水情况下,高温冻土的体积变形大于不排水条件下,围压愈大,这种趋势愈明显.更多还原

【Abstract】 To investigate the influence of drainage conditions on the stress relaxation features of warm frozen clay,a series of laboratory stress relaxation tests were conducted and the stress relaxation process under drained and undrained conditions of warm frozen clay is analyzed.The results indicate that confining pressure obviously influences the relaxation process of warm frozen clay.Under undrained condition,with confining pressure increasing,the critical relaxation duration,as well as the instantaneous relaxation,tends to increase.But for the relaxation rate,the influence of confining pressure is obvious in the initial stage of relaxation,but with further development of stress relaxation,the influence tends to diminish.Under drained condition,the relaxation rate is higher than that under undrained condition in the initial stage,but with the development of relaxation,the difference decreases.With prestrain magnitude increasing,the softening trends of volume versus time curve fade away,shifting from strain softening to strain hardening.The volumetric deformation of warm frozen clay under drained condition is much larger than that under undrained condition.更多还原