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针对三峡库区软岩的变形特性问题,对不同含水状态下T2b2紫红色泥质粉砂岩的蠕变特性展开试验研究。从桃树垭隧道现场采集新鲜的T2b2泥质粉砂岩,进行四种含水状态下T2b2泥质粉砂岩的单轴蠕变试验,获得不同含水状态下五级荷载的单轴应变-时间曲线,得到蠕变随应力水平变化及含水条件变化的一些基本规律和特征。结果表明:对于任何一种含水状态的试验,总体上初始瞬间应变随应力水平的增大而增大,由蠕变效应引起的蠕变应变也随应力水平的增大而增大,且随着应力水平的增加,蠕变达到稳定蠕变阶段时的应变速率也由零逐渐向非零常数转化;相同荷载水平不同含水条件的对比分析表明,随着含水率的提高,同级荷载情况下岩石蠕变进入稳定阶段所需的时间基本上会越长,蠕变加载瞬间应变越大,总应变量也越大,而岩石长期强度则呈减小的趋势。
In view of the deformation characteristics of soft rock in the Three Gorges reservoir area, the creep characteristics of T2b2 purplish red muddy siltstone under different water contents were studied. The fresh T2b2 argillaceous siltstone was collected from the Taoshuya tunnel and uniaxial creep tests were carried out on four T2b2 argillaceous siltstones under different water conditions to obtain the uniaxial strain-time curves of five levels under different water contents. Some Basic Laws and Characteristics of Creep with Change of Stress Level and Changes of Water-containing Conditions. The results show that for any water-containing test, the initial transient strain generally increases with the increase of stress level, and the creep strain caused by creep effect also increases with the increase of stress level. With the increase of stress level, When the creep reaches a stable creep stage, the strain rate also gradually changes from zero to a non-zero constant. The comparative analysis of different water conditions at the same load level shows that with the increase of water cut, the rock under the same load The time required for the creep to enter the stable phase is basically longer, the larger the instantaneous strain and the total amount of strain during creep loading, and the long-term rock strength decreases.