海底隧道支护结构的水压力问题十分复杂,影响因素较多,一直是人们关注的焦点。依托厦门翔安海底隧道,采用较大比尺的相似模型试验方法以及先进的光纤光栅测试技术,研究不同防排水方式下衬砌背后水压力分布规律以及水土压力共同作用下衬砌结构受力特征。试验结果表明:海底隧道在全封堵条件下衬砌背后水压力不能折减,注浆圈也不能有效减小水压力;而在排水条件下,衬砌背后水压力可以折减,且水压力随排水量的增加而减小;水土压共同作用下,地下水渗流场和应力场的耦合作用显著增大,并且以水压力为主,仰拱为最不利部位。通过对隧道开挖过程的模拟试验,得到开挖对前方土体的影响范围约为两倍洞径,施工过程初支只承受部分水压,能满足结构安全。
There have been arguments about water pressure on tunnel linings,due to the complexity and plethoric interfering factors.Based on the Xiamen Xiang'an sea tunnel project,similarity model test of a larger scale and advanced fiber grating technology was conducted to explore the water pressure distribution under various drainage conditions,the force characteristics of the lining under the effect of the water pressure and rock stress,and the water pressure distribution and force characteristics of the lining for the procedure of tunnel primary lining construction.This paper illustrates from the model tests that the water pressure cannot be reduced by lining and grouting ring for the whole block waterproof method,the water pressure reduces with the rising drainage for whole drainage.Comparing with significant superposition of the seepage field and stress field,the scope and value of tunnel lining structure enlarge markedly under the effect of the water pressure and rock stress,and the water pressure play the leading role,the invert is the most unfavorable position.When simulating the procedure of construction,it is found that the influence scale of tunnel excavation is about 2 time of the diameter of tunnel and the primary support only bear part of water pressure.