裂损隧道衬砌拆换施工过程力学分析

Mechanical Analysis of Lining Demolition ConstructionProcess of Fractured Loess Tunnel

某黄土隧道建成后衬砌出现严重的裂损,现场采用更换二次衬砌措施治理衬砌裂损问题。为了验证更换衬砌后的结构安全性,通过建立隧道三维数值模型,分析换衬纵向长度对衬砌的影响,及换衬后的结构稳定性。根据数值模拟结果并结合现场的监测数据,分别对衬砌顶部压力、靠近围岩侧混凝土应力以及净空侧应力进行分析。结果表明:衬砌上部压应力为拱顶最小,拱顶向拱肩两侧压力逐渐增大;衬砌靠近围岩侧混凝土应力明显大于靠近净空侧混凝土应力;随着更换衬砌的长度增大,拱顶应力减小而拱肩应力增大;同一监测断面,压力与应力最大位置出现在拱肩位置;采用更换衬砌治理措施有效控制了隧道衬砌裂损的病害,保证了衬砌结构的稳定性。

The lining of a loess tunnel has serious cracks after construction,and the secondary lining replacement measures are used to control the lining cracks.In order to verify the structure safety after lining replacement,a three-dimensional numerical model of tunnel is established to analyze the influence of lining longitudinal length on lining and the structural stability after lining replacement.According to the numerical simulation results and field monitoring data,the pressure at the top of the lining,the concrete stress near the surrounding rock side and the stress at the clearance side are analyzed respectively.The result shows that the compressive stress of the upper lining is the smallest in the vault,and the pressure from the vault to both sides of the arch shoulder increases gradually.The concrete stress near the surrounding rock side of lining is significantly greater than that near the clearance side,with the increase of lining length,the vault stress decreases and the arch shoulder stress increases,in the same monitoring section,the maximum pressure and stress appear in the arch shoulder position.The replacement of lining treatment measures effectively controls the disease of tunnel lining crack and ensures the stability of lining structure.