Analysis Of Influence Of Different Pore Size On The Compaction Effect Of Static Sinking Pipe-pile With Holes

Many treatment methods can be used to deal with bad foundation in engineering,among which the use of prestressed pipe pile is a common method since it is more suitable for soft ground treatment.To some extent,this kind of method improves the overall bearing capacity of the foundation.However,in the process of pile sinking,the soil around the pile will be squeezed to different degrees,and then the surrounding buildings and underground pipelines around the pile will be damaged.Faced with these urgent engineering problems,the research group proposed the pipe-pile with holes technology.By means of laboratory model test and numerical simulation,this paper studies and discusses the soil squeezing effect of static pressure pipe-pile with holes under different pore sizes.The main research contents and results are as follows:(1)Through laboratory model tests,the change of ultra-pore water pressure caused by pile sinking of pipe-pile with holes is studied.According to the results,the excess pore water pressure caused by the sinking of pipe-pile with holes and pipe piles is consistent with the radial and depth directions and conforms to the actual engineering situation.Under the same pore diameter,the peak value of the excess pore water pressure caused by pile sinking is smaller than that of non-pore pipe pile for the pipe-pile with holes with three hole patterns of unidirectional,bidirectional and stellate holes.And among them,the pile with stellate hole is the smallest.Under certain conditions,as the pore diameter increases,the peak value of excess pore water pressure caused by the sinking of the pipe-pile with holes decreases gradually,while its dissipation ability increases gradually.(2)Through laboratory geotechnical tests,The changes of physical and mechanical indexes of soil around piles before and after pile sinking were studied.The results show that the hole opening is beneficial to the consolidation and strength of soil.Under the same pore diameter,the three kinds of hole arrangement methods have different effects on the degree of consolidation and strength improvement of soil body,and the advantage of bidirectional hole arrangement is the most obvious,followed by stellate hole arrangement,while the unidirectional hole arrangement is the worst.Under certain conditions,the pore diameter is proportional to the consolidation and strength increase of the soil around the pile.(3)Through the use of FLAC3 D software,the generation and dissipation of excesspore water pressure in the process of pile sinking were numerically simulated and analyzed,and compared with the results of laboratory test,it was confirmed that the results of laboratory model test were correct.