Large Deformation Mechanism and Control of Tunnel Initial Support in Anticlinal Core Zone of Daliang Mountain
As the tunnel of Daliang mountain No.2 highway passes through the core zone of anticline with high in-situ stress,it is prone to large deformation in initial support stage,collapse and steel frame distortion,through the comprehensive analysis of on-site monitoring measurement,surrounding rock lithology experiment,theoretical analysis,numerical simulation analysis and surrounding rock contact pressure monitoring,genetic mechanism of large deformation in anticlinal core zone of Daliang mountain No.2 tunnel was studied.The results show that the uniaxial compressive strength of anticlinal core basalt is 23.31 MPa,tuffaceous mudstone has certain expansibility when exposed to water,it creates conditions for the deformation of surrounding rock.Due to the different lithology of rock strata,the basalt around the tunnel is in the state of independent bending shear beam after excavation.Under the condition of relatively no water,the area of plastic zone of surrounding rock increases due to the influence of groundwater recharge,and the arch waist is more obvious.Before reinforcement,the maximum settlement of the vault is 470 mm,the maximum convergence value of the arch waist is 844 mm,and the contact pressure of surrounding rock is 523.47 KPa.By adopting the comprehensive disposal method of"active adaptation+strong support"of double-layer small conduit+temporary support of middle step+temporary support of side wall,the tunnel vault deformation reduce by 87.6%,the horizontal convergence deformation reduce by 95%,maximum contact pressure of surrounding rock reduce to 128 kPa,the tunnel deformation is effectively controlled.
国家科技期刊平台
NSTL
万方数据
维普
