Study On Light Well Point Dewatering Technology In Deep Foundation Pit

At present,a large number of foundation pit due to the high underground water level,the earthwork excavation,the hydrodynamic pressure change,pit water level difference,more susceptible to erosion,sand flow,piping seepage failure phenomenon,which causes the upper and the surrounding strata subsidence and collapse;more water,more serious collapse.Therefore,how to deal with the groundwater is a major problem in front of each civil engineer.The light well point precipitation method as the research object,based on the precipitation method of foundation pits at home and abroad,briefly describes the foundation pit dewatering methods,problems of light well point precipitation have made a comprehensive description;analyzes the basic principle and method of the light well point dewatering construction technology and characteristics,put forward a new idea of improving the targeted prevention measures and technology,and its application in engineering is studied.Wuhu Country garden Jinghu spring two in sandy stratum,excavation pit size,low water,strict settlement around based on the situation,brought the problem of sand flow with light well point dewatering technology to solve the elevator well foundation.According to the project,a circular well point system is arranged in the elevator well for a week,and 37 light well points are used.The use of the four sets of pumping equipment.During the precipitation,record the precipitation and groundwater level in time,and draw the Q-t chart and H-t chart of the precipitation and the change of the water table elevation.The horizontal displacement of the retaining pile and the settlement of surrounding buildings and roads are monitored synchronously,and the s-t chart of displacement and settlement with time is plotted by monitoring data.Based on the analysis of relationship between precipitation,groundwater level,displacement and settlement and time,groundwater level has been reduced to less than-11.7m,meet the design requirements;the cumulative horizontal displacement of the retaining piles 5-6mm,far less than the warning value of 30mm;the surrounding buildings and road settlement 1?2mm,did not exceed the warning value of 5mm,stable condition good;3?5mm surface crack is a normal change,the foundation pit is stable and safe.Practice has proved that the use of light well point dewatering in the foundation pit is good,and the monitoring and early warning scheme is feasible.