高地温隧道围岩注浆节理不同法向应力下抗剪强度特性研究

Study on Shear Strength Characteristics of Grouting Joints in Surrounding Rock of High Ground Temperature Tunnels under Different Normal Stresses

采用高温变温的养护方法,制备初始养护温度分别为40,60,80℃与标准养护20℃的试件,在不同法向应力0.1,0.3,0.5 MPa下开展高地温隧道围岩注浆节理的直剪试验。结果表明:高温变温养护与法向应力都对注浆节理抗剪强度有明显影响。随法向应力增大,注浆节理抗剪强度不断提高,且随初始养护温度的增大,抗剪强度提高幅度更显著。高温变温养护的注浆节理抗剪强度会出现劣化现象;高温变温养护的注浆节理破坏模式主要表现为粘结界面破坏。

The specimens at initial curing temperature(40,60,80℃respectively)and at the standard curing temperature(20°C)were prepared by means of curing at high temperature and varying temperature,and then direct shear tests of grouting joints were carried out under different normal stresses(0.1,0.3,0.5 MPa).The shear strength characteristics of grouting joints in surrounding rock of high ground temperature tunnel under different normal stresses were studied,The results show that,both the curing at high temperature and varying temperature and the normal stress have obvious effect on the shear strength of grouting joints.With the increase of normal stress,the shear strength of grouting joints increases continuously,and as the initial curing temperature increases,the increase of shear strength is even more significant.There may occurs degradation at the shear strength of grouting joints in the condition of curing at high temperature and varying temperature.The failure mode of grouting joints in the condition of curing at high temperature and varying temperature is represented mainly by the failure of bonding interface.