Research On The Seepage-stress Coupling Lanzhou Metro Line Crossing The Yellow River Based On FLAC^3D

In the process of urbanization in our country,the increase of urban population,more and more people are crowding into cities.It will lead to the urban traffic congestion problem.The emergence of urban traffic congestion,hindered the sustainable development of the city seriously.In order to solve urban congestion problems and ease traffic pressure on the ground,people change the transportation from ground to underground,and construct the urban subway energetically.In the process of urban subway construction,inevitably there will be such problems as the subway crossing the rivers and lakes.When the subway crosses rivers and lakes,it will bring huge risks due to high water pressure and an infinite water supply.Especially when crossing the pebble soil layer,due to its high permeability,and the soil loose,may appear the gushing water and sand,the tunnel seepage problems.In the rich water pebble soil during tunnel excavation,seepage field-force field coupling calculation will become very important.Taking lanzhou city metro line 1 as the background,select YingMen beach ma beach,as the research section,the three-dimensional model was established based on finite difference software FLAC^3D.By the theoretical analysis and numerical simulation,analyzed the cross section of the Yellow River in lanzhou subway shield construction of the tunnel surrounding rock mass disturbances;by comparing the analysis without considering seepage field under the influence of constraints in jacking force of tunnel surrounding rock mass disturbances;and when considering the seepage field of tunnel driving different speed of tunnel surrounding rock mass disturbances.The following results is obtained by the above methods:?1?This paper reviews the present situation of seepage field-force field coupling at home and abroad,and discusses three different seepage field-force field coupling models.?2?In this paper,we introduce the theory of Bea consolidation in the basic theory of seepage field-force field coupling,and derive the solution conditions for seepage field-force field coupling.?3?The characteristic of FLAC^3D program was introduced.And the method of the principles and process of the simulation was illustrated.?4?A shield model which combined with every kind of impact factors was established based on the analysis of characteristic of construction and mechanical behavior of shield tunnel.?5?Taking the Yellow River section of Lanzhou subway line 1 as an example,considering the seepage field-force field coupling interaction of soil and water,the law of surface subsidence and pore pressure change caused by shield formation.?6?With the calculation model and method above,the law of impaction on the environment from the difference construction conditions and driving parameters was simulated.According to the above study,some new conclusion was drawn and the new achievement of this study can be used as guide to the construction of shield tunneling in similar stratum.