TBM隧道围岩压力及受力特征研究

Study on Surrounding Rock Pressure and Mechanical Characteristics of TBM Tunnel

以某隧道TBM掘进段为工程依托,采用现场试验的方法,对深埋大断面TBM隧道围岩扰动区、围岩压力分布范围、支护结构受力特征等展开研究。研究结果表明:围岩参数相同时,TBM隧道围岩扰动区比传统钻爆法隧道减少30%左右;围岩压力以形变压力为主,建议在围岩稳定范围内充分利用围岩的自承能力,延后TBM隧道初期支护时间;初期支护各部位的安全系数均大于2.0,能够满足施工期间的承载能力要求,但拱顶、拱腰及边墙安全系数较低,不宜长期作为主要受力结构,建议提前施作二次衬砌,提高支护结构体系的安全储备;二次衬砌与初期支护共同承受围岩荷载,且有一定的安全储备,验证了支护参数的合理性。研究成果为TBM隧道支护结构参数设计提供理论依据。

A field test is carried out to study the disturbed zone and pressure distribution of surrounding rock,and mechanical characteristics of support structure based on TBM excavation section of a tunnel.Test results show that comparing with the traditional drilling and blasting method,the disturbed zone of surrounding rock of TBM tunnel is reduced by about 30%with the same surrounding rock parameters;surrounding rock pressure is mainly based on deformation pressure,it is recommended to fully mobilize the self-supporting ability of surrounding rock in the stability of surrounding rock,and delay the initial support of TBM tunnel;the safety factor of initial support is more than 2,which can meet the requirement of carrying capacity during construction,but the safety factor is low,and it is not suitable be used as the main force structure for a long time,it is recommended to apply the second lining in advance to improve the safety reserve of the supporting structure system;the second lining and initial support bear the load of surrounding rock,and there is a certain security reserve,the rationality of supporting parameters has verified.The research results provide theoretical basis for the parameter design of TBM tunnel support structure.