| With the rapid development of the national economy,the population is moving more and more,people's demand for transportation is increasing,and higher standards and requirements for traffic environment and comfort are put forward.Highway tunnels have achieved rapid development due to their ability to overcome terrain elevation obstacles,improve road line shape,and shorten road mileage.However,most of the highway tunnels are located in complex geological environments.The surrounding rock mass is complex in structure.If the tunnel surrounding rock stability and tunnel structure deformation are improperly controlled during construction,it will bring very serious consequences.Therefore,the numerical simulation of highway tunnel construction process is carried out to analyze the stress and deformation characteristics of surrounding rock,and the physical and mechanical parameters of tunnel surrounding rock are analyzed based on the measured data of tunnel surrounding rock displacement,so as to ensure the safety of tunnel construction and surrounding rock.Stability has important significance and can provide some reference and reference for tunnel construction safety control research.This paper takes the construction of the shallow-buried section of the Mashan Tunnel in Zhusong Road,Qingdao as the engineering background.Using the combination of theoretical analysis,numerical simulation and on-site monitoring data inversion analysis,the following aspects are studied:(1)Firstly,combined with the research status of tunnel construction safety control and surrounding rock displacement inversion analysis,the analysis of tunnel surrounding rock deformation mechanism and surrounding rock stability analysis method,from tunnel rock mass state,tunnel depth and tunnel construction method In three aspects,the main influencing factors of tunnel surrounding rock stability are discussed,which lays a theoretical foundation for the safety control analysis of surrounding rock construction.(2)Using the MIDAS GTS NX finite element software to establish a three-dimensional numerical simulation analysis model for the shallow buried section of the Mashan Tunnel in Zhusong Road,Qingdao.During the modeling process,the rock mass is assumed to be elastoplastic material and conforms to Mohr-Cullen.Guidelines to consider the differences in mechanical parameters of rock mass materials between different rock layers.The numerical simulation results are compared with the on-site monitoring data to verify the reliability of the model analysis.(3)Using the established finite element model to simulate and analyze the shallow buried section of the Mashan Tunnel in Zhusong Road,Qingdao.The results show that the tunnel excavation breaks the original stress of the rock mass,and the stress is redistributed along the excavation surface and reaches a new balance.The stress concentration occurs at the intersection of the steel support and the surrounding rock.The maximum vertical compressive stress is 2.87 MPa,the maximum vertical tensile stress is 0.62 MPa,the maximum horizontal compressive stress is 1.57 MPa,and the maximum horizontal tensile stress is 0.32 MPa.The left side guide tunnel of the tunnel was excavated by CRD method.It was found that the settlement of the left guide tunnel arch was mainly caused by the excavation of the left upper guide tunnel,and its settlement displacement accounted for more than 90% of the left settlement displacement,which was affected by the left guide hole.When the right side guide hole is excavated,the settlement displacement of the arch roof superimposes the settlement displacement on the left excavation,and the settlement value on the right side is larger;the surrounding rock of the excavation tunnel is squeezed by the surrounding rock mass due to the unloading action of the soil.At the initial stage of tunnel excavation,the horizontal clearance clearance value of surrounding rock suddenly increases,and the supporting structure can effectively restrain the surrounding rock from converging deformation;the intermediate steel supports the stress concentration phenomenon in the unsupported surrounding rock,toward X positive and negative directions.The maximum stresses are 21.4 MPa and 4.2 MPa,respectively.The steel support needs to resist not only the external force generated by the convergence of the surrounding rock into the tunnel,but also the stress caused by the lateral deformation of the unsupported rock mass.(4)Using the method of mathematical regression analysis to fit the measured data of the horizontal convergence displacement and the arch settlement displacement of the ZK5+425 section of the Zhamashan Tunnel in Qingdao,and select the exponential function with the highest correlation coefficient with the measured displacement curve to the surrounding rock.The final deformation of the arch settlement and horizontal clearance convergence is predicted.The midas gts nx finite element software is used to inversely analyze the parameters of the surrounding rock of the tunnel according to the predicted deformation,and the physical parameters of the surrounding rock in accordance with the construction section are obtained.the amount E=1.292 GPa,Poisson's ratio ?=0.374 And using the measured data of three different sections of the same construction section ZK5+365,ZK5+475,ZK5+505,the relative error respectively proves the correctness of the inversion surrounding rock parameters.(5)According to the results of simulation and inversion analysis,in view of the problem of surrounding rock deformation and surface deformation during the construction of the Maomaan tunnel,it is proposed that the advanced duct grouting reinforcement and pipe shed grouting should be used in the tunnel construction process.The protection technology controls the deformation of the face of the face;the surface settlement deformation is controlled by the surface jet grouting pile reinforcement and the surface vertical anchor reinforcement. |
PDF Full Text Request