花岗岩-水泥砂浆界面水力耦合试验研究

Experimental study on hydraulic coupling of granite cement mortar interface

基于岩石三轴压缩应力—应变全过程渗透特性试验,研究在正应力作用下花岗岩/水泥砂浆两相介质胶结面抗剪强度及界面剪切破坏后的渗透率的变化。结果表明,花岗岩—水泥砂浆两相介质胶结面的抗剪强度破坏与单一试样抗剪强度破坏趋势相同,均有剪缩阶段和剪胀至峰值阶段两个阶段,且表明花岗岩—水泥砂浆两相介质胶结面是试样的脆弱面其强度与原有介质中强度较弱的水泥砂浆相差甚远。试样破坏后渗透率最大,在正应力的作用下,随着时间的增加渗透率逐渐减小直至趋于稳定,且渗透率变化速率也越来越小,渗透率的变化与在剪应力作用下试样破坏后产生的贯通裂缝的有着直接的关系,渗透率的大小与裂缝宽度的大小正相关。研究结果对于分析引水隧洞洞身段衬砌的抗剪切强度和渗透性有一定的意义。

Based on the triaxial compression stress-strain full-permeability permeability test of rock, the shear strength of the cemented surface of granite/cement mortar and the permeability after interfacial shear failure under normal stress were studied. The results show that the shear strength failure of the cemented surface of granite-cement mortar is the same as that of the single specimen, and there are three stages of shearing stage, dilatancy to peak stage and residual shear strength stage. It also shows that the cemented surface of the two-phase medium of granite-cement mortar is the fragile surface of the sample, and its strength is far from the cement mortar with weak strength in the original medium. After the sample is destroyed, the permeability is the largest. Under the action of normal stress, the permeability decreases gradually with time until it becomes stable, and the rate of change of permeability is smaller and smaller. The change of permeability and the shear stress. There is a direct relationship between the through cracks generated after the destruction of the lower sample, and the magnitude of the permeability is1 positively correlated with the size of the crack width. The research results have certain significance for analyzing the shear strength and permeability of the lining of the diversion tunnel.