考虑洞间影响的三孔并行海底隧道渗流问题分析

Analysis of Seepage Problems in Three-hole Parallel Subsea Tunnels Considering the Influence Between Tunnels

海底隧道渗流场的分析是隧道建设的基本问题,它与隧道围岩稳定性、工程防排水设施的布置密切相关.考虑现有的工程实际,海底隧道常采用"主隧道+服务隧道"的三孔并行方式穿越海峡.以实际工程为背景,建立了不同覆岩厚度下三孔并行海底隧道渗流计算模型,从涌水量、孔隙水压力、渗流速度、注浆参数方面分析了隧道渗流特性.研究结果表明,隧道互相靠近时,渗流场相互影响,无论是采用现行规范中所给出的隧道涌水量计算公式,还是精确解析解公式来预测三孔并行海底隧道主隧道涌水量时均会产生较大误差,将会高估隧道涌水量,最大误差可以达到40%;三孔隧道之间互为"泄压孔",降低了主隧道周边孔隙水压力和渗流速度;注浆作为隧道堵水的关键措施,考虑注浆圈厚度的同时也应该注重注浆的密实性.

The analysis of seepage fields in subsea tunnels is a fundamental issue in tunnel construc-tion,which is closely related to the stability of the tunnel surrounding rock and the layout of engineering waterproofing and drainage facilities.Considering actual engineering conditions,subsea tunnels often use the three-hole parallel method of"main tunnel+service tunnel"to cross the strait.Taking practical engineering as the background,a seepage calculation model for a three-hole parallel subsea tunnel with different overburden thicknesses was established.The seepage characteristics of the tunnel were ana-lyzed from the aspects of water inflow,pore water pressure,seepage velocity,and grouting parameters.The conclusions drawn are as follows:When tunnels are close to each other,there will be mutual inter-ference in the seepage fields.Whether using the tunnel water inflow calculation formula given in the current specifications or the precise analytical solution formula to predict the water inflow of the main tunnel of a three-hole parallel subsea tunnel,there will be significant errors,which will overestimate the tunnel water inflow with a maximum error of 40%;The three-hole tunnels act as"pressure relief holes"for each other,reducing the pore water pressure and seepage velocity around the main tunnel.As a cru-cial method for tunnel water blocking,grouting should not only take into account the thickness of the grouting ring but also prioritize the compaction of the grout.