非均质断层介质单双液加固特性对比

Comparison Research on Reinforcement Characteristics of Cement Slurry and C-S Slurry for Inhomogeneous Fault Medium

使用永莲隧道F2断层介质,预置单一结构面,基于不同结构面角度、水泥单液浆水灰比和注浆压力开展正交试验.试验表明:注浆压力、土压力和渗透压力均呈波动上升规律,但土压力和渗透压力相对较小;结构面α=0°、45°和90°试样在注浆后强度分别提升了189%,200%和64%,结构面α=45°试样加固前后强度均较低;应力-应变曲线显示,当应变达到0.015~0.04时,应力达到峰值;通过极差分析,本次试验条件下结构面角度是影响试样抗压强度的主控因素,其次为浆液水灰比,注浆压力影响最小;浆液充填结构面并劈裂断层介质形成的大尺寸浆脉发挥骨架效应,对加固体破坏产生控制性作用;揭示了水泥单液浆对于含结构面断层介质的充填、挤密和劈裂联合加固型式.从加固型式、加固效果和主控加固因素3个方面对比了水泥单液浆和C-S双液浆对于断层介质的加固特性.单液浆形成的浆脉尺寸更大;当α=0°和90°时,单液浆加固效果更佳,而α=45°时,双液浆加固效果更优.与单液浆不同,双液浆的主控因素为浆液配比.基于试验结论为注浆设计和施工提出了4条指导性建议.

The grouting reinforcement test on fault medium with a single structural plane of Yonglian tunnel was developed,which was under the conditions of different structural plane angle,watercement ratio of cement slurry and injection pressure. It was found that the injection pressure,soil pressure and seepage pressure showed a fluctuant increase law,but the soil pressure and seepage pressure were less than injection pressure. The uniaxial compressive strength of samples with α = 0°,45° and 90° were respectively increased by 189%,200% and 64% after reinforcement. The strength of samples with α = 45° were both low before and after the reinforcement. The stress-strain curves showed that stress reached the maximum value when strain was 0. 015 ~ 0. 04. Based on the results of extremum difference analysis,structural plane angle was the most important factor followed by water-cement ratio and injection pressure,which influenced the strength of samples. The grouting veins formed by filling and splitting played a role of skeleton during the process of compression. The fault gouge with a single structural plane was reinforced by means of filling,compaction and splitting. In terms of reinforcement mode,reinforcement effect and the dominant factor,the reinforcement characteristics of cement slurry and C-S slurry were contrasted. It can be concluded that the sizes of slurry veins formed by cement slurry are larger. The strength of samples reinforced by cement slurry are higher withα = 0° and 90°,whreas it is opposite with α = 45°. By using C-S slurry,slurry ratio is the most important factor to influence the strength of samples,which is different from cement slurry.