Research On Monitoring And Stability In Jingqiangyan Tunnel

Since the first world's mountain tunnel opened, people had gradually realized stability problems in the tunnel excavation. For keeping surrounding mountains'stability, the essence is to maintain the existing surrounding mountains, not to because of the excavation surrounding mountains'space in the great body of stress and destruction. It is tunnel excavation process that the process of redistribution of rock stress, this redistribution stress whether more than rock itself capacity is the key to stability of surrounding rock. However, when the NATM was proposed, it would be a good explain that the rock stress change process in the tunnel excavation and it had proposed a reasonable approach how to solve the stability problem of the tunnel rock in tunnel construction. To protect the rock strength and deformation of the original, the main contents of NATM are shotcrete and erection and technical monitoring to measure the deformation of the supporting rock. Monitoring on-site data collection, collation and data analysis to understand the trend of rock deformation,to predict the final deformation of surrounding rock in order to determine the stability of rock excavation process or not, to guide the construction of tunnel safety, it is also have a good reference and guidance on tunnel design.In order to clarify the Jinqiangyan tunnel adjacent formation under specific geological condition distortion change rule, possibly creates the adjacent formation jitter, the determining factor, the characteristic, the adjacent formation distortion destroys and so on, this article take the Jinqiangyan (Wenchuan-Ma Erkang) tunnel as the object of study, elaborated tunnel excavation forms the principle as well as the adjacent formation distortion destruction type and the mechanism, have discussed the major effect factor which in detail the adjacent formation destroys. According to the Jinqiangyan tunnel's engineering geology, the rock layer distribution, the hole room excavates, the adjacent formation graduation, the hydrogeological conditions, the supports and protections method and the method, as well as the geology stability appraisal situation, to the adjacent formation initial period supports and protections and two lining work processes, tunnel's gauging data has carried on the analysis to the Jinqiangyan tunnel, in the research many kinds of gauging information's processing method's foundation, put forward to the processing proposal. Through to monitors the data the regression analysis, forecast that excavates the adjacent formation distortion change tendency, in the judgment construction process, adjacent formation and supports and protections effect. The union tunnel adjacent formation monitor cross section's distortion characteristic, carries on the numerical analysis to the different adjacent formation rank's lining work structure stress, appraises the adjacent formation supports and protections using the lining work structure's secure coefficient the function, the judgment adjacent formation stability. Through carring on the adjacent formation to the tunneling the monitoring gauging and the lining work structure secure appraisal analysis, it had guaranteed the adjacent formation in excavates in the process the overall stability, enables the Jinqiangyan tunnel to be able smooth, the safe construction, also has confirmed the supports and protections method and the lining work structure is initially reliable.