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Numerical Analysis of the Surface Deformation for the Influence of the Construction of the Complicate Tunnel

Author: WanLing
Tutor: LiZhangMing；FengQiang
School: Guangdong University of Technology
Course: Geotechnical Engineering
Keywords: The large section spacing two holes tunnel Weak surrounding rock Overlying high-voltage tower Deformation law Numerical Analysis Comparative study
CLC: U455.4
Type: Master's thesis
Year: 2011
Downloads: 77
Quote: 1
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Abstract

With the rapid development of China's modernization, the construction of the tunnel project level is also rising. By the project in which the engineering geological conditions and Outside Tunnels conditions in the tunnel project the complex tunnel case also emerging, such as ultra-shallow, large cross section, small clear space two holes tunnel, such stability of surrounding rock is difficult to control, tunnel construction difficult. Furthermore, when the buildings around the construction site, building (structure), the stratigraphic disturbance and land subsidence caused by tunnel construction will also affect the safety and long-term nature of the surrounding buildings. Thus, the overlying important to build the project boundary conditions (structures) for ultra-shallow, large section, the complexity of the small spacing tunnel construction, construction difficulty and risk, the mechanism and construction of surface subsidence caused by surface settlement distribution pattern is extremely complicated, and this research at home and abroad rarely reported booming rapid development of such works and theoretical enhancement is very uncoordinated. Thus, the tunnel construction of the buildings around the building (structure) deformation impact analysis study, to ensure the safe use of the surrounding buildings and run an important role in guiding. In this paper, on the basis of research and summarizes the results of previous studies, in close connection with the Shenzhen Qilin Mountain tunnel projects, using the finite element software MIDAS / GTS were established two-dimensional and three-dimensional models, simulation tunnel under the conditions of the actual complex formation, implementation conditions deformation of the overlying high-voltage tower dynamic simulation, and analysis of surface deformation and deformation of the electric tower foundation at law. A parameters determine the two-dimensional construction simulation, the construction of the three-dimensional dynamic simulation of the mechanical response of the surface deformation law system. Main work as follows: 1, discusses the constitutive relations and numerical analysis of surrounding rock strength theory, including the yield criterion of the surrounding rock, the law of work hardening elastoplastic constitutive theory; discussion of the factors influencing the stability of surrounding rock, brief outlines the basic method to analyze the stability of surrounding rock. 2, discusses the geotechnical engineering numerical analysis parameter selection method and its OK. 3, using the finite element software MIDAS / GTS to establish a two-dimensional model, a dynamic simulation of different construction methods and engineering construction methods (double-side Drift multi-step method), analysis of tunnel surrounding rock deformation and the overlying high pressure The electrical towers deformation analysis. By MIDAS / GTS create a three-dimensional model simulated tunnel bias state, the construction of the multi-step method using double side Drift, the characteristics and laws of the deformation of the surface deformation and electrical tower foundation, and with the two-dimensional analysis and experimental results compare the discussion regularity in order to get a broader sense, the following conclusions: (1) three-dimensional simulation of the construction process in the cross-section cloud images and two-dimensional analysis of consistency of the law, and under the same calculation conditions, the three-dimensional analysis deform slightly smaller than the size of a two-dimensional analysis, and closer to the actual deformation. The two-dimensional analysis of the results showed that: surface subsidence curves into a normal distribution curve, from the tunnel axis than distant settlement tends to 0. Although the tunnel is bias, but the settlement curve basically Peck subsidence curves coincide. Surface horizontal displacement curves approximated to a sine function in nearly around the tunnel axis position, the horizontal displacement is close to zero. Surface horizontal displacement the directions tends axis direction, the left position in the central axis, the surface generated rightward horizontal displacement, and in a certain range gradually increases as the distance increases to more distant position in the central axis on the right , surface generating the leftward horizontal displacement, and in a certain range gradually increases as the distance increases to more distant to 0. The three-dimensional analysis of two-dimensional analysis with similar laws. (2) three-dimensional simulation analysis of tunnels under the conditions of the actual complex formation, the tunnel will surface Shen Long changes have a greater impact, will cause the tunnel beneath the electric tower where the cross-section of a larger settlement, but the settlement occurred after section excavation . (3) contrast Y = 35m cross-section (electrical tower where the cross-section) at Y = 90m cross-section at the (out of the hole profile) settlement graph shows that Y = 35m at into approximate normal distribution curve, with the two-dimensional analysis of electrical towers where the cross-section similar results, and Y = Om (profile) into the hole at the \Mainly by tunnel depth, ultra-shallow depth of Y = Om at the tunnel subsidence curves similar to the two single-wire tunnel caused land subsidence curves superimposed curve Y = 35m at a depth of relatively deep sedimentation The curve is equivalent to a radius slightly larger than the single-hole tunnel radius caused by ground subsidence, settlement theoretical research consistent with Peck. (4) by Y = 35m cross-section (electrical tower where profile) deformation graph shows that the tower foundation settlement curve is approximately linear distribution from the tunnel nearer surface subsidence the greater. Electric tower foundation horizontal displacement curves into approximate a straight line, close to the electric tower foundation horizontal displacement. The conclusion of the two-dimensional analysis where the electric tower section has a similar law.

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