Research Into The Breakthrough Deformation And Control Of Large Cross-section Soft Rock Tunnels

With the rapid development of the traffic network,the construction of the soft rock tunnel increasing.In recent years,due to the particularity of the soft rock tunnel,make the soft rock tunnel breakthrough period appear the phenomenon of excessive deformation of surrounding rock in the construction process,and,in turn,affects the tunnel construction progress,threatening the safety of construction personnel.Current research in view of the soft rock tunnel deformation control is more,but for the period of deformation control technology study is relatively small,therefore,further study of large cross section deformation of soft rock tunnel transfixion area control technology has certain necessity and urgency.Based on Jinpenwan tunnel which is located on the Jing-Xin high-speed project Jining to Hohhot section as the background,using the finite element software ABAQUS,2d and 3d through model is established,About how to control well versed in period of deformation of surrounding rock and tunnel excavation tunneling time more thorough discussion and research.In this paper,main work is as follow :(1)Combined with Jinpenwan tunnel transfixion area of displacement and stress monitoring results,pressure of surrounding rock and lining arch sedimentation of early stress were studied under three steps excavation method,settlement deformation,stress of surrounding rock and the stress variation are analyzed.(2)Combined with Jinpenwan Tunnel breakthrough area of the site construction situation,3d through-model is established and compared with field monitoring data,the rationality of the tunnel transfixion model is proved,for the phenomenon of tunnel site of disease before and after the reinforcement is obtained numerical simulation,the comparison and analysis to verify the site do the necessity and correctness.(3)Different surrounding rock reinforcement technology and different construction methods for Tunnel transfixion area in vault subsidence,peripheral convergence,aspects and so on surrounding rock stress are compared,put forward some reference suggestions.(4)To Jinpenwan tunnel site do method and strengthening technology as the basis,comparing to different excavating tunnel breakthrough period of single and double time to analysis and study,several kinds of tunneling is given under excavation method,the change rule of surrounding rock stress of the tunnel through one-way driving timing scheme optimization selection,for similar soft rock tunnel breakthrough with heavy section of the relevant construction technology and engineering provides a theoretical reference.