以天津站交通枢纽3标段基坑工程实践为例，利用数值模拟试验，分析施工中降水和开挖对地层沉降造成的影响，指出降水施工引发的沉降占总量的90%，开挖施工的不利影响主要体现在差异沉降上。在实际施工中应高度重视及时封堵隔水帷幕漏水和架设足量的内支撑，结合监测数据，对模拟结果进行分析，肯定盖挖逆作工法在沉降控制上的优势，并提出实际施工的优化方案。

The influence of dewatering and excavation on the ground settlement is analyzed by means of numerical simulation, with the construction of the foundation pit of No. 3 bid section of Tianjin Railway Station Terminal as an example. It is concluded that the settlement induced by dewatering takes 90% of the total, while the adverse influence of excavation mainly takes the form of differential settlement. Therefore, the water seeping through the waterproofing curtain should be timely sealed and enough waling should be set up during construction. Analysis is also made on the simulation results on basis of the monitoring data and conclusion is drawn that the cutandcover topdown construction method is superior in terms of settlement control. Finally, an optimized construction scheme is proposed.