水下长大明挖隧道接头优化及工程应用

Optimization and Engineering Application of Joints in Long Underwater Excavated Tunnels

摘要:

为解决水下长大明挖隧道变形缝渗漏频发的技术难题，以苏州独墅湖第二通道工程为依托，通过文献调研、数值模拟与工程实测相结合的方法，开展隧道接头设计关键要素优化研究。重点分析节段长度、变形缝宽度、差异沉降控制指标及基础形式对防水性能的影响，提出“枕梁+桩基”的新型接头方案。研究表明：水下明挖隧道变形缝差异沉降宜控制在10 mm以内；60 m节段长度搭配20 mm变形缝宽度可平衡结构应力与防水需求；“枕梁+桩基”方案能将变形缝两端差异沉降控制在3 mm以内，显著优于传统桩基方案。工程实测验证该方案可有效避免止水带撕裂，防水效果显著，为类似水下明挖隧道接头设计提供理论依据与工程参考。

Abstract:

To solve the technical problem of frequent water leakage at deformation joints in long underwater excavated tunnels, relying on the Suzhou Dushu Lake Second Channel Project, and through the combined method of literature research, numerical simulation and engineering measurement, the research on the optimization of key elements in tunnel joint design is conducted. The focus is on analyzing the impacts of segment length, deformation joint width, differential settlement control indicators and foundation types on the waterproof performance, and a new “sleeper beam + pile foundation” joint scheme is proposed. The results show that the differential settlement of deformation joints in underwater excavated tunnels should be controlled within 10mm, and a segment length of 60m combined with a deformation joint width of 20mm can balance the structural stress and waterproof requirements. The “sleeper beam + pile foundation” scheme can control the differential settlement at both ends of the deformation joint within 3 mm, which is significantly better than the traditional pile foundation schemes. Engineering measurements verify that this scheme can effectively avoid the tearing of waterstops and achieve the remarkable waterproof effects, providing a theoretical basis and engineering reference for the joint design of similar underwater excavated tunnels.