单线铁路隧道施工量测信息分析与初期支护优化研究

Measurement Information Analysis and Initial Support Optimization Research of Single Track Railway Tunnel Construction

以蒙(西)华(中)铁路连云山隧道为依托,通过现场量测发现锚杆性能未被充分利用,喷射混凝土最大压应力值仅为极限抗压强度的12. 9%,格栅钢架最大拉应力值仅为极限抗拉强度的14. 9%。通过强度折减法计算,Ⅲ级和Ⅳ级围岩的安全系数分别为3. 92,2. 78,能够保证隧道自稳,可对初期支护进行优化,并提出了"取消系统锚杆+增加结构强度"方案。经数值模拟该优化方案在理论上可行。通过现场试验验证,该优化方案喷射混凝土应力、锚杆轴力与原支护方案处于同一量级,优化设计合理。

Based on the Lianyunshan tunnel of Mengxi-Huazhong railway,the bolt performance was not fully utilized by field measurements,the maximum compressive stress of shotcrete was only 12.9%of the ultimate compressive strength,the maximum tensile stress of grill steel frame was only 14.9%of ultimate tensile strength.Calculated by strength reduction method,the safety factors of gradeⅢand gradeⅣsurrounding rocks were 3.92 and 2.78 respectively,which can ensure the stability of the tunnel and optimize the initial support,and the scheme of“canceling system bolt+increasing rigidity of structure”was put forward.The numerical simulation shows that the optimization scheme is theoretically feasible.Field tests verif ies that the optimization scheme of the shotcrete stress and bolt axial force are in the same order as that of the original support scheme,which means design optimization is reasonable.