深埋双线铁路隧道衬砌高水压分界值研究

为研究深埋双线铁路隧道衬砌高水压分界值以及高水压作用下的衬砌受力状态,基于双线铁路隧道设计标准,利用有限元软件计算和分析双线铁路隧道衬砌在不同水压作用下隧道衬砌安全系数的变化规律,确定双线铁路隧道衬砌的高水压分界值。研究结果表明:Ⅱ、Ⅲ级围岩条件下水压力在0~0.05 MPa(约等于隧道净高一半)和Ⅳ、Ⅴ级围岩条件下水压力在0~0.1 MPa(约等于隧道净高)范围内变化时,隧道断面安全系数基本不变。在Ⅱ、Ⅲ级围岩条件下,双线隧道的高水压第一分界值为0.08~0.20 MPa;高水压第二分界值可取为0.40MPa。在Ⅳ、Ⅴ级围岩条件下,双线隧道的高水压第一分界值为0.12~0.35 MPa;高水压第二分界值为0.50 MPa。双线铁路隧道采用标准设计图进行设计时,能够承受的最大静水头为50 m,超过50 m的静水头,则需要优化断面。

Research on Boundary Value of High Hydraulic Pressure on Lining in Deep-lying Double-track Railway Tunnel

In order to define the boundary value of high hydraulic pressure on the lining in deep-lyingdouble-track railway tunnel and the stress state of the lining subject to high hydraulic pressure, thechange rules of tunnel lining safety factors of double-track railway tunnel lining subject to different waterpressure are calculated and analyzed with the finite element software based on the standard designdrawings of the double-track railway tunnel, and the boundary value of high hydraulic pressure of thedouble-track railway tunnel lining is decided. The results show that when water pressure varies between0 and 0.05 MPa( equivalent to about half of the height of the tunnel) under grade Ⅱ and Ⅲ rockconditions and when water pressure varies between 0 and 0.1 MPa(approximately equal to the tunnelclear height) under grade Ⅳ and Ⅴ rock conditions, the safety factor of tunnel section is almostinvariant. Under grade Ⅱ and Ⅲ rock conditions, the first boundary value of high hydraulic pressure is 0.08~ 0.20 MPa, and the second boundary value is 0.40 MPa. Under grade V and IV rock conditions, thefirst boundary value of high hydraulic pressure is 0.12~0.35 MPa, and the second boundary value is 0.50 MPa. When the double-track railway tunnel is designed with the standard design drawings, themaximum static water head it can bear is 50 m. However, the cross section should be optimized if thestatic head is higher than 50 m.