破碎板岩隧道应力监测及大变形风险分析OA

To investigate the stress variation and large deformation risk of fractured slate tunnels during excavation,this paper utilized the Dali Tree Tunnel project as a case study,employing fiber Bragg grating(FBG)sensors to monitor and analyze the three-dimensional stress of the surrounding rock.The tunnel's large deformation risk was assessed based on the strength-to-stress ratio of the surrounding rock.The results indicate that the stress variation in the surrounding rock can be divided into compressive stress zones and tensile stress zones,with stress variation absolute values yet to converge.The maximum vertical stress variation at a depth of 0.6 m in the vertical borehole under the invert reached 1.514 MPa,while at a depth of 0.5 m in the horizontal borehole of the right-sidewall,it reached 0.461 MPa.When the tunnel's burial depth exceeds 86.11 m,there is a po-tential risk of Grade Ⅲ large deformation during construction.Therefore,enhanced monitoring of surrounding rock deformation during construction is recommended.