Numerical Simulation Of The Stress And Displacement Of Tunnel In Different Stress Release Rate

With the development of economic that it will led to the development of science and technology, and the requirement of the tunnel are higher and higher.Tunnel excavation and construction in support, surrounding rock stress release, then it will affect the stability of surrounding rock, causing rock mass stress redistribution when such a re-distribution of stress over the limit of he intensity of the surrounding rock,it will inevitably that the rock will result in loss undermine the stability, so the release of stress-rate in the process of the tunnel construction determines the initial support of the tunnel lining and secondary support of the Security played an important role, whether it is reasonable of the structure of the tunnel will be reflect through it, as well as for rock tunnel Stability and reliability evaluation of the supporting structure of an important factor.The paper use flac3d software to build model of the tunnel excavation process and the supporting structure to carry out numerical simulation under the different release of stress-rate. In order to reflect the universality of the results of the paper, respectively, simulates the Ⅲand Ⅳ、Ⅴ grades tunnel rock.First,this paper for the V grade surrounding rock, respectively, using the CRD method,up and down stairs France, and full-face method to carry out excavation, then compared the stress and displacement of the three excavation methods under the same stress release rate, got a different excavation method to obtain the different displacement and stress,all of the displacement of full-face method is the largest,up and down steps method take second place,again,the method of CRD, in addition,in the same kind of excavation method,along with the increase of stress release rate displacement are also on the increase. And at the same time wo also compared the stress of V grade surrounding rock,obtain that stress relase rate has a big influence on the stress,growth neary the30%.Second for the Ⅳ grade surrounding rock,using up and down stairs France to carry out excavation, so that we can compare to the result of the V grade surrounding rock, in order to obtain the affect of rock displacement and stress that the rock classification in the case of different stress release rate; that is the displacement of V grade surrounding rock significantly greater than IV grade surrounding rock under the same stress release rate.And the last we use full-face method to carry out excavation for III grade surrounding rock,then compare to the result of the V grade surrounding rock, once again to obtain the affect of rock displacement and stress that the Rock Classification in the case of different stress release rate, that is the displacement of V grade surrounding rock significantly greater than Ⅲgrade surrounding rock under the same stress release rate. Compared by this various, we hope that we can obtain the best method and the stress release rate to carry out excavation for a certain level of surrounding rock, achieve the purpose of guiding the design and construction.