The Optimization Of Reinforcement In The Foundation Pit Considering The Effect Of Time

The foundation pit engineering is an ancient subject, but there're still many problems needing further research. The increase of the pit's depth and size carries some difficulties to the protection of the surroundings around foundation pit. It is mainly the ground settlement caused by the exaction, which even induces serious accident. There're many ways to control the displacements, such as strengthening the retaining structures or the stiffness of bracing system or reinforcing the internal and the external soil of the foundation pit. The paper mainly optimizes the reinforcement of the internal soil integrating the creep behavior of the soft clay of Shanghai area.The paper firstly quotes the relevant previous researches and analyses the mechanics properties of the reinforced soil. Because the reinforced soil is beneath the surface and surrounded by the moisture soil, it's disadvantageous to the conservation. Thus the stiffness changes obviously as time goes by. The parameters referred to the regressed curve from laboratory. But the reinforced soil is arranged in grid styles, which decrease the mechanics property, so some discounts were made during simulation.Secondly analyze the creep behavior of the soil and point out the influence caused by soil creep of Shanghai area, as well as some creep problems needed to be considered during excavation. Finite Different Method was used to analyze the foundation pit engineering, and the results were reasonable. The paper adopts the FDM, and introduces the geotech analysis soft named FLAC^3D, and analyzes the theory of the Burger-creep viscoplastic construction model.Then generate the engineering model referring to reality and obtain a economical reinforcement range through simulation. At the same time the paper compares the changes of the retaining structures displacement before and after reinforced. At last it shows a series of useful conclusions, which can be used to direct the projects so that makes the foundation pit engineering more economical andreasonable.At last the paper analyzes the conclusion considering the present engineering in Shanghai area. It says that the reinforcement is useful to control the deformation of the retaining wall, as well as reduce the extra influence caused by soil creep.The soil theory is under developing and has some problems. The paper ignores some unsolved problems which influence little to the results. As a result the paper summarizes the work done during forming, and points some problems, and considering which brings out further research.