Study On Deformation Mechanism And Control Technology Of Weak Rock Surrounding Tunnel

In recent years, the railway tunnel construction is increasing constantly. With the development of railroad span type, the speed construction for the railway has been demanded more fast. Railway tunnel engineering, especially long and large railway tunnel engineering is usually the key part of the whole railway line construction. The construction period is relatively long and construction technology is quite complex, so how to adopt the reasonable technological scheme and select appropriate construction machinery supporting to solve a variety of specific case of technical problems so as to achieve rapid tunneling effect has become a hot issue in the construction of tunnel. Paper relies on Tianchi ping weak surrounding rock tunnel engineering, It gives a detailed description of geological features, geological structure and hydro logical geological features,and thus summary out TianChi ping tunnel weak surrounding rock for thin layer-like carbon quality board rock, rock body broken and block structure, part lots into mud-like, section acting fractured development, seepage larger, easy along structure surface collapsed collapse, and off block, rock comprehensive strength low features. In such conditions, several sliding events, and the quality of construction safety, construction and construction progress would happen. So how safely and stably to engineer is become a focus. In these difficulties, which includes extra-long railway tunnel construction organization and management, machinery disposition,numerical simulation and field monitoring, construction scheme optimization as well as the key factors and remains to the problem. This paper draws the following conclusions:1, TianChi ping tunnel with weak surrounding rock engineering geological complex, rock crushing, strip, massive structure, part into the mud, joint fractures, large geological features, such as water seepage, in order to timely access to deformation of surrounding rock convergence of information, DK286+487 and DK286+497 sections of the tunnel face monitoring and measuring of displacement. Monitoring data show that causes deformation of tunnel surrounding rock affected by bias is the main reason, then may be the same different excavation support in the early part of the resulting closing time, so in the course of the excavation of the tunnel, to try to schedule less disturbance to the surrounding rock to have a reasonable excavation operations.2, Accuracy of characteristic parameters of surrounding rock of the tunnel restricted the development of finite element model, in displacement back analysis of tunnel section of DK286+530. Monitoring and measuring of displacement back analysis and combination of underground engineering reliability prediction can be, determined by the displacement back-analysis method of tunnel surrounding rock E =1.07 GPa,K0 = 1.31. And bring the data into the model, the relative displacement values for the location of, fitting and displacement related to the final value of the error is within 13%, reflect the inverse analysis of parameters has the certain reference value.3, Some parts of the tunnel invert major uplift, resulting in the bottom structure large, split. In order to better control of tunnel lining deformation, invert the tunnel lining deformation control study and experimental research of Grouting reinforcement of surrounding rock. Test data show that the Grouting reinforcement of surrounding rock grouting and chemical grout type, location of the Grouting for grouting effect has some influence in different rock characteristics and different parts of the tunnel structure to take the appropriate measures for grouting.4, TianChi ping tunnel geological disasters indicated that initial support of soft rock tunnel arch Department of settlement and Arch than hard rock deformation of tunnel at initial stage of convergence deformation capacity, and invert bump is quite severe and initial support deformation and tunnel geometry, section sizes, rock type and water content of the rock has a close relationship. So the optimal construction of soft surrounding rock tunnel is very important. By MIDAS-GTS finite element principle, different excavation tunneling model, and based on a tunnel construction site conditions, choose the more suitable for the excavation of soft surrounding rock three-step seven laws, and through further optimization analysis to determine the influence of bench height of tunnel deformation, and thus come to when the bench height is short, it is more conducive to the stability of tunnel surrounding rock.