隧道断层泥注浆加固机理模型试验研究

 为研究永莲隧道断层泥注浆加固机制，设计一套由注浆工艺模块、被注介质模块和信息采集模块构成的断层泥注浆加固试验系统，开展断层泥注浆加固体单轴压缩试验、典型浆–岩界面特征试验和扫描电镜(SEM)试验。结论如下：注浆后断层泥单轴抗压强度可提升181%～2 535%，加固体呈现浆脉开裂→界面附近土体破坏→整体破坏特征，断层泥以骨架式加固模式为主，注浆压力是提升加固效果的主控因素；注浆后浆–岩界面黏聚力可提升93%～274%，分析不同注浆压力、材料和初始干密度对浆–岩界面强度的影响，相比双液浆，单液浆可使界面黏聚力提升幅度增加125%～148%；注浆后断层泥由絮状结构转化为密实整体结构，浆–岩界面是具有一定厚度的不规则结构体，由胶结面、渗透过渡区及微劈裂过渡区构成，界面附近存在物理力学特征突变区，定义了浆–岩界面的直接及间接加固模式。试验结论对于注浆加固理论的认知和注浆工程的应用有一定的指导作用。

MODEL TEST ON GROUTING STRENGTHENING MECHANISM FOR FAULT GOUGE OF TUNNEL

In order to investigate the mechanism of grouting strengthening the fault gouge of Yonglian tunnel，a test system including a module of grouting technology，a module of injection medium and a module of information collection was designed. The orthogonal uniaxial compression tests，tests for the typical characteristics of pulp-rock interfaces and the scanning electrum micrographs(SEM) tests for fault gouge were carried out. The uniaxial compressive strength of the fault gouge was increased by 181%–2 535% after grouting. The strengthened mass was damaged through the process of the cracking of pulp veins，the breaking of the pulp-rock interfaces and the failure of the soil grout composite. The fault gouge was strengthened by the skeleton strengthening mode，and the key factor for raising the grouting effect was the grouting pressure. The cohesion of the pulp-rock interfaces was increased by 93%–274% after grouting. The influences on the strength of pulp-rock interfaced under the different grouting pressures，materials and initial dry densities were analyzed. When the cement slurry was used，the cohesion was increased by 125%–148%. The fault gouge was transformed from the floc structure into the overall densified structure after grouting. The pulp-rock interface was composed of the cementation plane，the transition area of permeability and the transitional area with micro factures. The direct and indirect strengthening modes of the pulp-rock interface are defined.