Experimental Study On The Clogging Mechanism And Anti-clogging Method Of Pervious Concrete Pile By Vibrating-sinking Tube

Permeable pile refers to the pile that has both water permeability and load-bearing capacity.As reinforcing body of composite foundation,it can not only improve the bearing capacity of the foundation,but also accelerate the consolidation of the foundation and reduce post-construction settlement.In recent years,as a kind of permeable pile,pervious concrete pile has begun to be widely used,but partial clogging will occur during construction and foundation consolidation,resulting in reduced permeability.Among them,the clogging caused by the construction process of vibrating-sinking tube is the most important.When the construction is carried out,the soil around the pile will be liquefied,while the pile material is not hardened and is still in the state of fluidization.Therefore,during the construction and after a period of construction,the soil particles migrate to the porosity in the permeable concrete and cause clogging.In this paper,the clogging mechanism of the pervious concrete pile caused by the vibrating-sinking tube construction was revealed through indoor model test and CT scanning,and the anti-clogging technology of the pervious concrete pile was proposed.It was not only of great significance to the design and construction of the pervious concrete pile,but also has important theoretical innovation value.The main contents are as follows:(1)The mixing ratio design of the pervious concrete was carried out,and the mixing ratio of the four target porosity was determined.And the saturated powder foundation was prepared.Then the pervious concrete pile was divided into normal type and geotextile anti-clogging type.The process of vibrating-sinking tube was simulated by self-made model system,and the pervious concrete piles after clogging were obtained.(2)CT scanning test of the clogging pervious concrete pile\~was carried out.and the influence of porosity on the clogging of pile was analyzed from the four respects:porosity change after clogging,clogging depth,clogging soil proportion and permeability coefficient.And it is found that as the porosity increased,the clogging depth increased,the clogging soil proportion increased.and the permeability coefficient decreased.At the same time,the anti-clogging effect of geotextile was verified.It is found that the anti-clogging effect of geotextile was fine,the specimens were not clogged under all porosity,and the measured porosity was close to the target porosity,indicating the model test was successful.(3)Comparing the effects of different porosity and conditions on the dissipation of the excess pore water pressure caused by the vibrating-sinking tube method,it is found that the larger the porosity,the smaller the dissipation time,and the deeper the depth,the greater the excess pore water pressure;And comparing different conditions,it is found that the deeper the depth,the more obvious the dissipation effect of anti-clogging pervious concrete pile;(4)Comparing the compressive strength of the two conditions and exploring the relationship between porosity and strength,it was found that porosity and compressive strength were nonlinear negative correlation.And as the porosity increased,the compressive strength decreased,while the compressive strength of the two working conditions was not much different.