拔桩前降水和桩孔回填对地表及邻近建筑物的变形影响研究OA

During the process of pile pulling construction,the surface and adjacent buildings may experience various deformation due to the disturbance of soil stress.Dewatering pressurized water and backfilling pile holes are important procedures for pile pulling.Analysis and selection a reasonable plan for dewatering pressurized water and backfilling pile holes can not only ensure the safety of adjacent buildings,but also maximize save the cost of the project.There-fore,a 3D numerical model of depressurized water and pile hole backfilling was established to analyze the influence of precipitation before full rotation pile pulling and pile hole backfilling construction after pile pulling on the defor-mation of the ground and adjacent buildings.The research results show that a distributed precipitation scheme is more effective than a centralized one,and can effectively avoid adverse phenomena such as water and sand gushing when installing pressure reducing wells.With the decrease of the backfill rate of pile holes,the cumulative settle-ment of each measuring point shows a linear increase.In the early stage of pile pulling,the cumulative settlement of each measuring point changes relatively little;When 7～15 piles are pulled out,the cumulative settlement of each measuring point increases rapidly;In the later stage of pile pulling,the cumulative settlement of each measuring point tends to be stable.Based on construction experience,in order to ensure that adjacent buildings are not affected by pile pulling construction,a mixture of clay,lime,and cement with a strength not lower than that of the original soil for backfilling is recommended with the cement content not less than 8％.