强岩溶地区盾构隧道注浆处理方案设计

Grouting design for shield tunnels in strong karst areas

摘要:

岩溶地质对地铁隧道施工存在不利影响，会带来安全隐患并增加施工难度。基于南京至句容城际轨道工程勘测资料对区间内溶洞进行分类，总结类似强岩溶地层处理经验后提出相应处理原则，采用三维有限元模拟确定岩溶处理范围，并提出相应岩溶处理措施：采用袖阀管注浆对隧道外轮廓起3 m内溶洞进行处理；其孔位布设遵循探至溶洞边界的原则，周边孔选取水泥-水玻璃双浆液，中央孔选取纯水泥浆；将注浆压力与注浆量作为终注指标并采用钻孔取心法对注浆效果进行检验使其满足强度、密实度与渗透性要求。现场钻孔取心发现，处理后的心样完整连续，水泥-土混合物密实，验证了本方案的可行性。

Abstract:

Karst geology has negative impact on subway tunnel construction， and may bring potential safety hazards and increase construction difficulty. Based on the exploration data of the Nanjing to Jurong intercity rail project， the karst caves in the interval are classified， the karst treatment experience of similar strong karst formations are summarized， and the relevant treatment principles are proposed. The three-dimensional finite element simulation is used to determine the karst treatment range with the corresponding treatment measures proposed. Sleeve valve tube grouting was used to treat caves within 3m of the outer contour of the tunnel with the deployment of the grout holes reaching the cave boundary as the criteria. The dual-fluid slurry of cement-water glass was injected from the peripheral holes， while plain cement slurry was injected from the central holes use. The grouting pressure and the grouting amount were taken as the final injection index， and grouting effect was checked by using the drilling core method to meet the requirements on strength， compactness and permeability. The core samples were found to be complete and continuous after treatment， and the cement-soil mixture was dense， which verified the feasibility of the grouting design.