Impact On The Environment And Research For The Underground Engineering Activities In Marine Soft Soil Area

This article summarizes the current existing research on the soft soil deep foundation engineering, baseing on some Shenzhen marine soft soil areas subway station engineering,through indoor soil test and insite monitoring, combining with theoretical analysis and finite element numerical simulation methods,we discussed the stability, the effects on precipitation of foundation engineering, indicated some practical engineering measures for future similar works. The main jobs and conclusions are as follows:(1)Based on a series of laboratory tests with reshaped soft soil,including one dimensional compression test,triaxial compression test,deformation characteristics of soft siol on different drainage condition.Through a seris of analysis,indicated:there were many factors impacting on the deformation characteristics of soft siol,such as the initial consolidtation, drainage condition, load ratios and so on;the ralaionship between coefficient of secondary consolidation and consolidation pressure depended on preconsolidation and load ratio in the test.(2)Aimed at the time effect of the deep foundation,using the finite element software,the calculated model were estabished.The effect of the model parameter on the deformation of the soil and deformation and stress of the retaining structure,indicated:the effect of the consolidtation of the soil on the deep foundation is great,as the siol consolidtation increasing,the soil subsidence reduced, deformation of the retaining structure also reduced some.(3)Confined water in the project of the exvacating deep foundation and see the flow of the underground water.Also based on the stochastic medium theory, seepage theory and visco-elasticity theory, a new calculation method which taKing the seepage into account was concluded, combining with the adding theory,this paper educed the distributed formula for the surface subsidence.(4)Based on the actual the soil defotmation theory,we analysis the relationship of defotmation of the retaining structure and time based on the insite measured data and result of the finited element calculated, the sequence of digging and controlled point in the deep foundation project in the marine soft soil areas were formulated accordingly.Understanding the theory of the foundation deformation and influenced factors rightly, design and construct according to correlated standard and criterion strictly, security and economy of the deep foundation could be guaranted entirety.