裂隙岩体损伤的注浆加固效果试验

Grouting reinforcement of fractured rock mass based on damage mechanics

为了研究岩体的裂隙损伤及注浆加固恢复效应,基于损伤力学理论,引入损伤变量,构建综合岩体损伤和超声波测速定量评价裂隙岩体注浆加固效果的方法。通过室内试验模拟岩体裂隙损伤及注浆加固过程,应用超声波检测技术测定岩体在不同裂隙宽度下的声波传播速度,进而推算岩体动弹性模量,并对比分析注浆前后裂隙岩体的损伤变量与动弹性模量的变化程度及规律。结果表明:注浆前后岩体损伤变量均与裂隙宽度成正相关;同一裂隙宽度下,泥岩的损伤变量最大,为0.89;灰岩最小,为0.57;注浆后,裂隙岩体损伤变量明显减小,且岩体动弹性模量明显增大,其中砂岩动弹性模量增加幅度最大,为354.82%;泥岩次之,为174.15%;灰岩最小,为85.75%.根据实验室结果对比分析,提出注浆加固变量,建立分级分岩性定量评价注浆效果的新方法,并应用于现场实践。

In order to study crack damage and reparation effect of grouting in jointed rock mass,based on damage mechanics as well as introducing damage variable,composite rock mass damage and ultrasonic velocity measurement were built to quantify the reparation effect of grouting in jointed rock mass. The grouting reinforcement process and crack damage of fractured rock mass were simulated through laboratory experiment. Dynamic elastic modulus was reversely calculated through the application of ultrasonic testing technology,which could measure the acoustic wave propagation velocity in different crack width.Therefore,the changing rules between dynamic elastic modulus and damage variable were analyzed before and after grouting. The result shows that there is a positive correlation between mass damage variable and crack width before and after grouting. For the same crack width,the damage variable of mudstone is maximum,while limestone is minimum（ 0. 89 and 0. 57,respectively）. After grouting,the damage variables decrease and dynamic elastic modulus increase obviously. The increment of dynamic elastic modulus of sandstone is the largest,reaching 354. 82%,followed by mudstone（ 174. 15%） and limestone（ 85. 75%）. According to the laboratory results,with the research of reinforcement variable,a new method of lithology grade assessment was built to quantify the grouting effects,which could be successfully applied to the field practice afterwards.