为解决超大直径盾构隧道超浅覆土始发，洞门密封容易水土流失、掘进姿态和管片姿态难以控制的问题，结合春风隧道工程始发端地质情况和工程的实施条件，采取端头加固U型素地下连续墙包裹+三重管旋喷加固的方式加强止水效果，洞门分层分块破除降低施工风险；采取调整掘进坡度、固定负环管片保证其成型效果。同时，针对盾构在软土地层中超浅埋始发，易出现隆起冒浆等问题，采取反压盖板的方式，增大上部覆土压重，同时合理降低泥水舱压力，降低地表隆起的可能性，从而保证盾构始发的泥水正常循环，最终形成了一套超大直径盾构在超浅覆土始发施工技术方法。

Superlarge diameter shield launching with shallow overburden faces many problems such as water loss and soil erosion at portal sealing and difficult control of tunneling and segment attitudes. As a result, a case study is conducted on shield launching of Chunfeng tunnel. According to the geological and engineering conditions, the strengthened water sealing method of Ushaped plain diaphragm + triple pipe jet grouting is adopted, the sectioned breaking is adopted for portal to reduce the risk, and as well the tunneling slope is adjusted and the negative ring is fixed to guarantee the effect. Moreover, for slurry leakage phenomenon, the methods of adopting back pressure cover, increasing earth pressure on upper part, and reducing slurry chamber pressure are used to reduce uplift of ground, thus ensuring normal cycling of slurry for shield launching. Finally, a suite of superlarge diameter shield launching technology with shallow overburden is formed.