土石混合体地层桩承式隧道施工力学模拟分析

蔡成曦¹，姜志远¹，殷永波¹，赵新¹，胡世兴²，靳晓光²

1.中铁二十一局集团第五工程有限公司，重庆  402160；2.重庆大学土木工程学院，重庆  400045

摘要：为提高土石混合体区隧道施工的安全性，以某隧道工程为依托，采用软件FLAC^3D建立土石混合体地层中的隧道模型，模拟隧道施工过程，得到土石混合体地层中预注浆桩承式隧道的变形破坏特征、隧道支护结构变形和受力规律。结果表明：隧道围岩变形可分为迅速变形、缓慢变形和变形稳定3个阶段，围岩塑性区从注浆区拱腰内侧向外侧发展，直至整个注浆区都发展为塑性区，发生剪切破坏；预注浆隧道的安全系数为1.7；二次衬砌能有效减小地表沉降，二次衬砌整体变形特征为沉降；桩基上部产生微弱弯曲。

关键词：土石混合体；桩承式隧道；变形；塑性区；二次衬砌

Mechanical simulation analysis of pile supported tunnel construction in soil rock mixture stratum

CAI Chengxi¹, JIANG Zhiyuan¹, YIN Yongbo¹, ZHAO Xin¹, HU Shixing², JIN Xiaoguang²

1.China Railway 21st Bureau Group Fifth Engineering Co., Ltd., Chongqing 402160, China;

2.College of Civil Engineering, Chongqing University, Chongqing 400045, China

Abstract:In order to improve the safety of tunnel construction in the soil rock mixture area, based on a tunnel project, the tunnel model in the soil rock mixture layer is established by using the software FLAC^3D to simulate the tunnel construction process, and the deformation and failure characteristics of the pre-grouting pile supported tunnel in the soil rock mixture layer, the deformation and stress law of the tunnel support structure are obtained. The results show that the deformation of the surrounding rock of the tunnel can be divided into three stages: rapid deformation, slow deformation and deformation stability. The plastic zone of the surrounding rock gradually develops from the inside of the arch waist of the grouting area to the outside until the whole grouting area develops into a plastic zone, and shear failure occurs; The safety factor of pre grouting tunnel is 1.7; The secondary lining can effectively reduce the surface settlement, and the overall deformation characteristic of the secondary lining is settlement; Weak bending occurs at the upper part of the pile foundation.

Keywords:soil-rock mixture; pile supported tunnel; deformation;plastic zone; secondary lining