石英砂岩蠕变力学特性及长期强度研究

通过三轴压缩蠕变试验,分别以过渡蠕变法、等时应力-应变曲线法、稳态蠕变速率与应力关系法、残余应变法以及强度与破坏时间关系法研究石英砂岩的长期强度.结果表明,对于石英砂岩的长期强度,前4种方法得到的结果大体一致;过渡蠕变法、残余应变法只能根据应力梯度得到长期强度临界值,等时应力-应变曲线法取拐点的过程具有一定主观和随意性...

Study on Creep Mechanical Properties and Long-term Strength of Quartz Sandstone

Through triaxial compression creep test,the long-term strength of quartz sandstone is studied by transition creep method,isochronous stress-strain curve method,steady-state creep rate stress relationship method,residual strain method and strength failure time relationship method respectively.The results show that,(a)for the long-term strength of quartz sandstone,the results obtained by the first four methods are generally consistent;(b)the transition creep method and residual strain method can only obtain the long-term strength critical value according to the stress gradient,the isochronous stress-strain curve method is subjective and arbitrary,and the long-term strength values of quartz sandstone obtained by the steady-state creep rate and stress relationship method respectively are slightly less than that of isochronous stress-strain curve method as the two methods being influenced by the rock steady-state creep development degree;and(c)in view of the shortcomings of the traditional steady-state creep rate and stress relationship method,the method of taking the intersection point of shear points on the left and right sides of the curve is improved.The long-term strength of quartz sandstone under confining pressure of 4,8 MPa and 12 MPa is 19.63,27.65 MPa and 37.07 MPa respectively with the reduction range of 33.4%~34.5%.