Stability Analysis Of Surroundingrock In Qingdao Metro Construction Through Fault Fracture Zone

In recent years,with the economy development of major cities,the subway has become an indispensable means of transportation to alleviate the current situation of traffic congestion.The subway construction encounters more and more problems such as the fault.All kinds of geological disasters often bring loss of life and property when the tunnel passes through the fault.However the current research of tunnel mainly concentrats in the deep buried hills and mine tunnel,the study of the surrounding rock stabilityg in city subway crossing is important.In this paper,the establishment of rock stability model for metro tunnel crossing different distribution faults was studied through numerical simulation,analysis of the changes,rules of the stress field and displacement field.By combining the results of numerical simulation,incremental dynamic displacement response and actual engineering to guide the construction.The main contents of the research work:1.Through studing investigation of subway tunnel construction we could find the stress field changes and dynamic analysis of excavation process.We could summarize the characteristics and main influencing factors of surrounding rock deformation through engineering geology,rock mechanics and other related content,.This paper analyzes the fault causes,types and the influence and to the tunnel.The treatment methods of the tunnel through the fault has been giving,too.2.Using Midas GTS/NX to simulate different types of faults,and finally I find the most influential faults.By studying about the effect of distribution,spacing,angle analysis of faults on the stability of surrounding rock,the stress field of displacement has changed.The paper determines the maximum influencing factors on the stability of tunnel surrounding rock.And the results shows that the number and spacing of the smaller,more acute angle and smaller angle of stress,the displacement of tunnel deformation is more serious and less stable.Analysising dynamic displacement of excavation unloading in the square in front of the tunnel face rock deformation shows that the fault will effect displacement of the first magnitudeand.The stability of surrounding rock in subway tunnel passing through fault is studied.Through the simulation of tunnel excavation with different groundwater level,it is concluded that the tunnel has the smallest stress and deformation when the groundwater level is below.3.Using the incremental dynamic displacement response ratio theory to analye the stability of tunnel surrounding rock,establishing the dynamic displacement response ratio theory model,comparative judgment exists when the condition changes,the different response ratio changes.Determining the stability of surrounding rock during tunnel excavation could find the position of maximum fault on the tunnel stability.The results responses peak ratio in the fault,indicating that the system is in the unstable state.The stability of surrounding rock when the subway tunnel passing through lots of water fault is studied.The analysis shows that the stress and deformation are minimum when the tunnel is below the ground water level.4.Combining the engineering monitoring data,the results of numerical simulation and comparative analysis,we could find the influence of each index of surrounding rock stability.By monitoring the stress and strain of the surrounding rock in the excavation process basing on guidance for practical engineering construction.