循环加卸载下岩石浆体力学特性试验研究

Experimental Study on Mechanical Properties of Grouting Material Under Cyclic Loading and Unloading

为研究循环加卸载下岩石浆体力学特性,利用RMT-150B岩石力学试验机对岩石浆体进行恒定围压下的循环加卸载轴压的岩石力学试验,对岩石浆体的强度和变形特征进行了分析。结果表明:岩石浆体随着下一级加载轴压的提高,塑性滞回环面积增加;低应力状态下的循环会使岩石浆体更加致密,岩石浆体在加卸载下的强度高于常规三轴,超过临界强度时就会发生破坏,强度随岩石粒径增加而降低;在循环加卸载下,岩石浆体以剪切破坏为主,低围压和粗粒径更易形成明显的剪切带。基于研究成果,提出了增高锚杆预应力和增强注浆效果的软岩注浆加固关键技术。

To study the mechanical properties of grouting material under cyclic loading and unloading,rock mechanics tests of constant confining pressure,cyclic loading and unloading axial pressure were carried out on rock slurry using RMT-150 B rock mechanics testing machine,and the strength and deformation characteristics of grouting material were analyzed.The results show that:the area of plastic hysteresis loop increases with the increase of axial pressure of rock slurry;the circulation under low stress state will make the rock slurry denser,and the strength of the grouting material under loading and unloading is higher than that the conventional tri-axial compression test,failure occurs when the critical strength is exceeded,and the strength decreases with the increase of rock particle size;under cyclic loading and unloading,the grouting material is mainly shear failure,and the low confining pressure and coarse particle size are more likely to form obvious shear bands.Based on the research results,the key techniques of soft rock grouting reinforcement for increasing bolt pre-stress and reinforcing grouting effect are proposed.