Study On Slurry Test And Mechanical Characteristics Of Geotextile Tube Dewatering Pile Foundation

Slurry is one of the important materials for bored pile construction,and also one of the main sources of engineering waste.The "ecological and environmental protection" treatment of waste mud has always been a difficult problem in engineering construction.In order to reduce the volume of waste pile foundation mud in-situ dewatering,based on the comparative tests of different dewatering methods,this paper optimizes and constructs the method of in-situ dewatering pile foundation mud by geotextile tube.Through experimental research and theoretical analysis,the deformation characteristics and stress calculation method of geotextile tube in the filling process are discussed,and the engineering application is carried out,It provides a foundation for the efficient treatment of waste pile foundation mud and the later resource utilization.The main research contents and conclusions are as follows1.Taking the pile foundation mud as the research object,the natural air drying test of pile foundation mud,the filtration test of different media and the dehydration test of different materials of geotextile tubes were carried out successively.The results show that the dewatering efficiency of natural air drying method is low and it is easy to be affected by rainfall;After flocculation,the filtration effect is the best when the mesh fiber geotextile is used as the medium;The bag body of geotextile tube should be made of mesh fiber geotextile.2.Field tests of filling and dewatering of geotextile tubes were carried out with waste pile foundation slurry as filling material.By arranging flexible displacement meter,pressure box,osmometer and displacement measuring points inside and outside the geotextile tubes,the development laws of the shape of geotextile tubes,the strain of bags and the water and soil pressure in the bags were tested.The test results show that the stress of the geotextile tube is not uniform during the filling and drainage process;The transverse strain of the top surface of the geotextile tube is small in the middle and large on both sides;The transverse strain is greater than the longitudinal strain;During the filling process,the mud pressure and pore water pressure of the geotextile tube have a good consistency,which increase with the increase of mud filling amount.After filling,the mud pressure and pore water pressure dissipate with the discharge of water in the mud;The mud pressure distribution in the geotextile tube is mainly affected by the gravity stress of mud and pumping pressure.The pressure at the bottom of the geotextile tube is higher than that at the end of the geotextile tube and the top of the geotextile tube.3.Based on Darcy’s law,the calculation method of geotextile tube height and average consolidation degree of slurry is established.4.In this paper,the change of geotextile tube shape during the filling process is divided into three stages: oblong,steamed bread and round.Through theoretical analysis,the corresponding calculation methods of shape and geotextile tube tension are established.5.The engineering application of dewatering in situ treatment of waste pile foundation mud geotextile tube is carried out,and the technical and economic analysis is carried out.