隧道沿线溶洞的加固处理是岩溶地层中盾构隧道施工的关键。以广州地铁某区间盾构隧道施工为背景，论述砂土覆盖型岩溶地层中盾构隧道施工面临的主要工程地质风险；由溶洞处理流程入手，从溶洞处理判断标准、注浆填充方案、注浆材料选择以及注浆加固效果检验等方面详细介绍盾构隧道施工中通过地面注浆加固进行溶洞处理。同时，对监测区间内溶洞注浆加固效果以及隧道掘进引起的地面、房屋沉降情况进行监测分析。研究结果表明： 溶洞注浆加固效果良好，隧道掘进造成的地面房屋沉降变化平稳，地面注浆加固处理在砂土覆盖型岩溶地层盾构隧道施工中具备一定的工程适用性。

The reinforcement of karst cave is the key to shield tunnelling in karst areas. In this paper, the main geological risks when shield boring in karst strata with sandy soil cover are discussed; and then the ground surface reinforcement technology is introduced in terms of estimation standards of karst treatment, grouting program, grouting materials selection and grouting effect examination. Meanwhile, the grouting effect and the ground surface and building settlement are monitored. The study results show that: 1) The grouting reinforcement has reached good effect.2) The ground surface and building settlement induced by shield boring varies steadily.3) The ground surface grouting reinforcement is suitable for shield tunneling in karst strata with sandy soil cover.