苏埃通道工程南岸海域围堰内地层结构复杂，上部为回填土、淤泥质土，中部为砂层，下部为强风化、中风化岩层，岩石强度高，且槽段内有大量潜在孤石。为解决该复杂地层条件下连续墙施工的技术难题，例如上部软土层易塌方，下部孤石强度高、不稳定，斜面基岩难以引孔、取芯，风化岩层中成槽机不能有效施工等，通过优化、改进施工技术，形成“槽壁预先加固、成槽机抓取软土、密集钻孔+冲锤冲击破碎孤石、旋挖钻机和成槽机钻抓配合挖除风化岩层、牙轮钻钻取斜面基岩”的施工工艺 ，并通过严格控制施工管理作业程序，实现平行作业，大幅提高连续墙施工效率。研究结果可为同类工程的施工提供参考。

The strata structure of sea cofferdam in south shore of Su′ai Tunnel is complex. The upper part is backfill and mucky soil, the middle part is sand layer, and the bottom part is stronglyweathered and moderatelyweathered rocks with high strength, and there are a lot of potential boulders in the groove. In order to solve the technical problems of diaphragm wall construction under complex conditions, i.e. easy collapse of upper soft soil layer, unstable lower boulders with high strength, difficult borehole drilling and sampling of inclined bedrock, and low efficient trenching machine, the construction technologies are optimized and improved. And then the construction technology of "prereinforcement of groove wall, grabbing of soft soil by trenching machine, dense drilling of boulder and impact crushing by the percussion hammer, weathered rock removing by rotary drill and trenching machine, and inclined bedrock drilling by rollerbit hole rig". Finally, by strictly controlling the construction management procedures, the parallel operation can be realized and the efficiency of diaphragm wall construction can be greatly improved. The results can provide reference for similar projects in the future.