姜路岭炭质页岩隧道围岩压力合理取值研究

Study on the Reasonable Value of Surrounding Rock Pressure for Jiangluling Carbonaceous Shale Tunnel

在姜路岭隧道工程建设中,由于炭质页岩土体特殊的力学特性,当采用规范经验公式计算所得的围岩压力进行隧道的支护结构设计时,支护结构所提供的支护力明显不足,易出现大变形和坍塌事故。因此,文章以共玉公路姜路岭隧道为例,通过理论分析、数值计算以及现场实测数据对比分析等手段,研究姜路岭炭质页岩隧道围岩塑性区分布规律、围岩压力计算方法以及合理的围岩压力取值等。研究结果表明,对于炭质页岩隧道围岩压力宜采用弹塑性分析的方法,围岩塑性区影响半径可取32 m,隧道围岩侧向压力与竖向压力相当。在无试验条件和实测数据的情况下,围岩压力压力可近似取0. 83 MPa进行隧道支护结构设计。

With respect to construction practice of Jiangluling tunnel,because of the special mechanical characteristics of the carbonaceous shale,when the surrounding rock pressure calculated by the standard empirical formula is used to design the supporting structure of the tunnel,the supporting force provided by the supporting structure is obviously insufficient,it is prone to appear large deformation and collapse accident.Therefore,based on Jiangling tunnel on Gongyu road,and by means of theoretical analysis method,numerical calculation method,comparative analysis method of field measured data and so on,the plastic zone distribution law of tunnel surrounding rock,the calculation method of surrounding rock pressure and the reasonable value of surrounding rock pressure for the Jiangluling carbonaceous shale tunnel ware studied.The results indicated that:for the surrounding rock pressure of the carbonaceous shale tunnel,the method of elastic-plastic analysis should be adopted,the influence radius of surrounding rock plastic zone is suggested to take thirty-two meters,the lateral pressure of tunnel surrounding rock is the same as vertical pressure.When there are no test conditions and measured data,the surrounding rock pressure can be taken approximately 0.83 MPa to design tunnel support structure.