Experimental Study On Filtration Properties Of Nonwoven Goetextiles Under Biaxial Tension

With the wide application of geotextile in civil water conservancy,road and railway,slope engineering,river bank and port,roadbed and pavement engineering,as a filter layer to play infiltration,soil preservation,anti-filtration,etc.However,during the long-term use of geotextiles,due to the action of soil on the geotextiles(which is usually manifested as the tensile strain caused by the action of soil),the anti-filtration performance of the geotextiles will change,the pore diameter will change,and the geotextiles will become blocked or leak soil.Therefore,it is of great application value to study the effect of tensile strain on the anti-filtration performance of geotextiles.In order to judge the working condition of geosynchronous fabric filter layer in a short time,Calhoun proposed to measure the change of head loss in soil and geotextile systems,and named it gradient ratio test.The gradient ratio test is usually used to study the anti-filtration performance of geotextiles in the world,and the blockage of geotextiles can be judged according to the gradient ratio GR.In this paper,the gradient ratio tester is used to test geotextiles of different types and thicknesses,and it is found that geotextiles are easy to form blockage under different types and different strain states.For the specific research,gradient ratio test is used.Firstly,the geotextile is tensioned on the drawing machine into the strain state designed for the experiment,and then the geotextile strain is assembled on the permeation meter to ensure that it does not relax.The soil particles needed in the test were screened by the sieving method,and the obtained soil with a certain particle size was used as the test soil.During the test,the head loss difference between the filter layer and the soil mass,the permeability coefficient of the filter layer system,the permeability of geotextile fabric,and the amount of soil leakage were measured to comprehensively evaluate the blockage caused by the soil-geotextile infiltration system.It is found from the test results that the larger the thickness of the geotextile and the larger the strain state,the more likely it is for the anti-filtration system.When geotextiles are used in practical engineering,the working conditions of the geotextile-soil filtration system should be taken into full consideration to avoid the blockage of geotextiles from affecting the engineering application.