Experimental study on the treatment of engineering waste slurry by flocculation-graded prefabricated horizontal drain vacuum preloading
In response to the serious problems of plate bending and blockage in the treatment of high water content engineering waste slurry using vacuum preloading with vertical drainage(PVDVP),a coagulation grading horizontal drainage plate vacuum preloading method(F-G-PHDVP)is proposed by combining two anti-blockage technologies-flocculation and grading method.This method can further alleviate the clogging problem caused by fine particle migration.Indoor model tests were conducted on Wenzhou pile foundation waste mud to compare and analyze the reinforcement effect and blockage of traditional,flocculation,and flocculation-graded vacuum preloading methods.The test results showed that the grading flocculation method had the best reinforcement effect.Compared to the traditional group,the flocculation group can increase the vane shear strength by 83.5%.On the basis of flocculation,the flocculation graded drainage capacity is increased by 4.03%to 12.73%,the average vane shear strength is increased by 1.91%to 5.66%,and the average moisture content is reduced by 1.66%to 4.27%.The flocculation-graded vacuum preloading method not only increases the average particle size,but also effectively slows down the migration of fine particles,preventing the aggravation of clogging and further improving the reinforcement effect.Among them,the vacuum loading method of 30-80 kPa can further improve the reinforcement efficiency by 4.1%.To verify the feasibility of this method for on-site treatment of pile foundation waste mud,a 30-80 kPa scheme was selected for vacuum preloading field tests.The results confirmed that this scheme has a good reinforcement effect on high water content waste mud.