海底隧道施工过程中初期支护受力特征试验研究

以厦门翔安海底隧道为依托工程，采用相似模型试验方式，研究在海水渗流场和围岩应力场共同作用下，隧道施工过程和变水头过程中，衬砌背后水压力的分布规律及受力特征．研究结果表明，隧道施工期间，在水土压共同作用下，隧道开挖对前方土体的影响范围约为2倍洞径，隧道开挖过后约1倍洞径，初期支护背后水压及应力趋于稳定；在变水头过程中，控制水的排放量对调整初期支护背后水压，保证隧道结构的安全起至关重要作用．试验所得结论与现场情况基本一致．

Laboratory investigation on the mechanical characteristics of primary support in subsea tunnel under condition of construction process

Based the Xia Men Xiang An sea tunnel project, the distribution of water pressure and force characteristics around the lining are studied under the effect of the water pressure and soil pressure during subsea tunnel of construction process by using the similarity model test. According to the research results, Through simulating the procedure of construction under condition of both water pressure and soil pressure, it is found that the influence scale of tunnel excavation is about 2 times of the diameter of tunnel, meanwhile, the water pressure and the stress will become stable after forward excavation length equals to the diameter of the tunnel. In the variable water head, the control of drainage plays a vital role in adjusting water pressure behind the primary support and ensuring the safety of the tunnel structure. The conclusions of model test are consistent with that of site situation.