合理确定衬砌水压力是海底隧道结构设计的关键所在。采用复变函数和地下水动力学理论，推导了圆形海底隧道衬砌外水压力解析法计算公式，经对比验证，精度高、适用性广。通过海底隧道水压力模型试验研究得到，全封堵防水方式下，衬砌背后水压不能折减；限量排放时，衬砌背后水压力随排水量的增加而减小，建立了限量排放下的水压力计算公式，得到现场实测结果验证。研究成果应用于国内第一条海底隧道──厦门翔安海底隧道，为“以堵为主、限量排放”的支护结构设计和海底风化槽地段注浆堵水方案的制订提供了关键技术参数，现场应用成效良好。相关研究成果对后续海底隧道工程具有一定借鉴意义。

The reasonable water pressure upon lining determination is the key to structure design of subsea tunnel. The analytic method calculation formula of outside pressure upon lining of circular subsea tunnel was derived with complex function and groundwater dynamic theory. It was verified that the calculation formula is high precision and extensive applicability by lots of contrast. Results of model tests showed that under the condition of fully closed, the pressure on lining could not be reduced; the water pressure would significantly reduce if the water of the tunnel was drained, and it would be presented linear decreasing with the increase of the water discharge. Lining external water pressure formula under limited drainage was established, and it was also verified by field tests. The research results were applied in the first subsea tunnel in China, Xiang'an Subsea Tunnel, which is built in Xiamen. And it provided key technique parameter to determination of support structure design and programme of blocking water by grouting, following the principle plugging dominantly and limited drainage. The field application obtained good results. Research results would have certain reference significance to the following subsea tunnel.