Research On Tunnel Face Extrusion Effect Under High Ground Stress Soft Rock

With the economic development, population growth and the development of city scale, human survival environment continues to change, resource scarcity, per capita living space reduce, traffic congestion, Ecological imbalance and so on.Those problems have bad influence on the development of world economy. Therefore, governments around the world in order to promote the development of economy and to solve the problems of the urban congestion, they gradually began to focus on the development of city underground construction, plane to construct a large number of underground engineering. Sinec the new China was founded, the construction of tunnel in our country has made outstanding achievements, attracted the attention of the world.New Italian method is found by the famous Italian scholar Mr Pietro Lunardi, also known as the deformation of rock and soil control analysis. The method response the reason of tunnel deformation, Put forward a set of theoretical analysis and practical engineering measures. Especially under the condition of soft and fractured, by adopting the constraints and constraint measures and constraints-lead core soil tunnel surrounding rock, to realize the whole section excavation construction, has the advantages of safety, high efficiency and control time limit for a project and cost.In this thesis, a second line of lanxin High-speed rail as the engineering background, the soft rock tunnel construction under high groundstress condition exist tunnel face extrusion problems, the science mainly completed the following several aspects study:1. As one of the main forms of large soft rock deformation, to study the mechanism of tunnel face extrusion first make the mechanism of soft rock large deformation clear, this thesis from the definition of soft rock, the characteristics of soft rock large deformation and the mechanism of soft rock large deformation as the three respects of the mechanism of extrusion; At the same time, in order to timely and effective predict Rock stability in construction process, this thesis presents a simple and easy prediction method to predict tunnel face extrusion.2. In the second chapter of this thesis puts forward the technology to control tunnel face extrusion deformation, and combined with the DaLiang tunnel field test done, by comparing the test results, comparative analysis of the supporting technology on the control effect; At the same time, the content of this chapter also puts forward extrusion deformation monitoring method, obtained the extrusion deformation value and the relationship between the damage condition of surrounding rock, provide the basis for guiding the construction.3.At last, this thesis using the large general finite element analysis software FLAC3D to Simulation several construction methods of DaLiang tunnel, through the comparison and analysis DaLiang tunnel extrusion displacement value under the condition of different construction methods, conclusion the methods that can effectively control extrusion, provide the reference for the construction of tunnel surrounding rock.