| As the depth of the foundation pit deepens,the groundwater situation of the foundation pit becomes more and more complicated,resulting in frequent engineering accidents caused by unfavorable precipitation.Therefore,it is very important to drain the water in the aquifer of the deep foundation pit during dewatering.Especially under complex geological conditions,good groundwater treatment has become the core of determining the success or failure of foundation pit engineering.The problem of aquifers being drained during pit precipitation is studied,the reasons leading to the aquifers being drained and the countermeasures for solving the problem of aquifers being drained are sought,and the following work has been done for this purpose:This article first takes a deep foundation pit project in Handan City as the research background.Aiming at the problem of lack of aquifer during the construction of the foundation pit,the main reasons for the lack of dryness of the foundation pit are found through field investigation: Complicated geological conditions lead to uneven aquifers,improper selection of precipitation methods,and failure to completely cut off the hydraulic connection between the inside and outside of the foundation pit.Combined with the actual situation of the foundation pit site,the hazards of the foundation pit engineering caused by the lack of aquifer are summarized.Finally,through on-site tests and consulting related documents,the countermeasures to solve the problem of dry aquifers are proposed.Then,based on the FLAC3 D finite difference method numerical simulation software,a numerical simulation analysis of the undried aquifer was carried out,and a comparative simulation method was used to verify the reasons for the proposed lack of dry aquifer.Through the analysis of the pore water pressure cloud chart,the pore water pressure curve with time and the trend of the falling funnel obtained by the numerical simulation,it is concluded that the vacuum tube well dewatering can effectively solve the problem of the drainage of aquifers,and the tube well dewatering in a uniform aquifer can quickly form a dewatering funnel,The use of a bottom-type water-stop curtain during precipitation is very effective for accelerating the drainage of aquifers.Finally,the dewatering design of the deep foundation pit project is introduced,mainly including the information that should be investigated and provided before dewatering,the content of dewatering design and the type of dewatering design.It is determined that the background project of this paper belongs to the third type of precipitation design.On this basis,the precipitation design scheme was optimized,and physical modeling was performed on the precipitation design optimization scheme.The numerical simulation results confirmed that the optimization scheme was feasible to solve the problem of dry aquifer. |
