| The design and monitoring of foundation pit usually only consider that the ground subsidence.In fact,different strata and different recharge conditions show great differences.In view of the above problems,this paper conducts a series of studies to study the settlement rules around the foundation pit under different soil layers and different recharge conditions.According to the recharge conditions,it can be divided into three types: the influence of rainfall recharge on foundation pit precipitation on settlement,the influence of aquifer recharge on settlement,and the influence of confined aquifer precipitation on settlement.The settlement of soil around the foundation pit under different soil layers was systematically studied.The main work and conclusions of this paper are as follows:(1)Finite element software GeoStudio is used to analyze and study the settlement deformation of surrounding soil under these three recharge conditions.In the short-term calculation,the influence of recharge on settlement is not significant,but in the long-term calculation,whether the influence of recharge on settlement will have a greater impact on the calculation results.(2)the settlement calculation results with the results of rainfall recharge stagnant water supplies were similar.The analytical solution of stagnant water recharge seepage is deduced by heat conduction method.Through the analytical solution to the various cases of comparative analysis,find the corresponding law.The tables and curves which are convenient for engineering calculation are obtained by normalization.(3)For a model with a confined aquifer,the paper introduces the related boundary onedimensional surface settlement consolidation equation,and the formula is applied to the calculation of settlement of two-dimensional,analyzed the applicability of the formula,explained the difference caused by the space effect when the two-dimensional results are applied to the three-dimensional analysis,and proposed the corresponding solution to solve the actual three-dimensional calculation.(4)The simple one-way flow,large well formula and one-dimensional consolidation settlement formula were used to calculate and analyze the settlement.It was found that the water stopping effect of the water curtain was significant for the settlement of soil around the foundation pit.If the water stopping effect of this kind of stratum was not good,it would have a great and far influence on the surrounding area.Different from pure soft soil,for pure deep soft soil,even if there is no anti-seepage measures,the settlement at the foundation pit edge is large,but the influence range is small.(5)Two numerical examples are given to illustrate the application of the analytical solution formula for the recharge of a simple aquifer of soft soil and the calculation formula for the head settlement of surrounding soil mass under the pressure relief of a confined aquifer of deep soft soil. |
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