水下盾构隧道管片接缝防水密封垫截面设计研究

Section Design of Shield Waterproof Gasket in Underwater Shield Tunnel

汕头湾海底隧道是国内外首座设计时速为350 km的单洞双线高速铁路海底隧道,采用1台直径14.57 m泥水平衡盾构机施工。盾构段水压达0.84 MPa,管片接缝处防水主要通过设置双道三元乙丙橡胶弹性密封垫实现。为研究合理的密封垫截面型式,确保管片接缝防水能够满足铁路运营要求,采用非线性有限元软件ABAQUS,对初选的内、外道密封垫断面建立二维有限元模型进行计算分析,根据压缩反力曲线、压缩形态,接触面应力大小及分布情况等指标综合分析确定内、外道密封垫断面4为推荐方案;利用“T”形模拟水压试验台对推荐方案断面进行最不利工况下防水试验验证,确定内、外道密封垫断面4可用于汕头湾海底隧道盾构管片接缝防水。

Shantou Bay Subsea Tunnel is the world's first single-hole double-track high-speed railway subsea tunnel with the design speed of 350km/h.It is constructed with one slurry balance shield machine of 14.57m diameter.The water pressure in the shield section is as high as 0.84 MPa.The waterproofing of the joints is mainly achieved by installing double EPDM elastic gaskets.In order to study the reasonable section type of gasket and ensure that the Shield waterproof gasket meets the requirements of railway operation,a two-dimensional finite element model of the primarily selected section is established for calculation and analysis by ABAQUS.No.4 internal and external section scheme is recommended based on comprehensive analysis of compression reaction curve,compression shape,contact surface stress size and distribution.Then the“T-type”simulated hydraulic test bench is used to verify the recommended scheme under the most unfavorable working conditions,which approves that No.4 internal and external section of gasket can be used in Shantou Bay subsea tunnel shield segment joint waterproofing.