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利用岩石双轴流变试验机,对水泥砂浆浇筑的不同角度的规则齿形结构面试件进行了剪切蠕变试验和松弛试验。试验结果表明:蠕变曲线与松弛曲线形态相似,都有衰减和稳定两个阶段,全过程曲线都呈阶梯状变化,松弛曲线为非完全应力衰减曲线;采用Burgers蠕变模型和松弛模型对蠕变曲线和松弛曲线进行拟合,吻合程度较好。除了参数G1外,蠕变模型的参数值比松弛模型的参数值大;在分析松弛速率与应力水平关系的基础上,提出了用分级加载松弛试验确定长期强度的方法,即:松弛速率拐点对应的剪应力为岩石的长期强度,此方法与稳态蠕变速率确定长期强度的机理一致,而且两种方法确定的长期强度值相同。
By means of rock biaxial rheological testing machine, shear creep test and relaxation test were carried out on the regular tooth profile test specimens with different angles of cement mortar pouring. The experimental results show that the creep curves are similar to the relaxation curves, both of them have the decay and the steady state. The curves of the whole process change stepwise and the relaxation curves are the incomplete stress decay curves. Burgers creep model and relaxation model Curve and relaxation curve fitting, a good degree of agreement. In addition to the parameter G1, the parameter values of the creep model are larger than those of the relaxation model. Based on the analysis of the relationship between the relaxation rate and the stress level, a method of determining the long-term strength by the step loading relaxation test is proposed. The shear stress is the long-term strength of the rock. This method is consistent with the mechanism of steady-state creep rate determining long-term strength, and the long-term strength values determined by both methods are the same.