Experimental Research On Flocculation Combined With Vacuum Preloading To Reinforce Reclamation Silt Foundation

At present most of the domestic reclamation formed hydraulic fill foundation can be developed using all required after vacuum preloading handling.Although vacuum preloading technology has been widely used in large-scale engineering practice,but there are still drain filter clogging serious,vacuum degree of soil loss greater,evacuated latter silt permeability reduced caused drainage problems and other issues.Therefore,the existing vacuum preloading technology needs further improvement and innovation,so as to effectively improve the effect of hydraulic fill mud foundation reinforcement.In this paper,learning from a flocculation technology is widely used in domestic and foreign sewage sludge treatment which is incorporated into the soft foundation treatment field.For ultrahigh moisture content hydraulic fill sludge carried out a series of indoor model test studies of flocculation joint vacuum preloading method hydraulic fill sludge.The main contents are as follows:(1)According to the flocculating mechanism of hydraulic filling mud selected eight different kinds of flocculants respectively into the same mud soil samples.Carried out cylinder deposition characteristics test,permeability test,microstructural characteristics and consolidation characteristics test.More detailed analysis of influence of sedimentation rate and bleeding characteristics in flocculation for hydraulic filling mud natural deposition process and change of permeability coefficient,microstructure and compression index after deposition.It provides a theoretical basis for the study of the reinforcement mechanism of flocculation-vacuum preloading.(2)Carried out flocculation joint vacuum preloading of more pharmaceutical agents in the same amount invested indoor model comparison test and single agent indifferent amount flocculation-vacuum preloading model comparison test.Detailed introduction working principle and crafts of flocculation-vacuum preloading.Systematically studied soil degree of vacuum distribution,pore water pressure and displacement variation with time in the process of flocculation-vacuum preloading reinforcing hydraulic filling mud and the moisture content and the vane shear strength change with the soil depth after reinforcement.Have found a flocculant suitable for Wenzhou reclaimed silt and determined the optimal dosage.It can provide reliable basis for the application and development of flocculation-vacuum preloading.(3)Used self-designed hydraulic fill model test device designed by simulation of reclamationarea of construction site of dredger fill in the pipeline transmission while in the process of injection and blow the flocculant again from the pipeline construction process.Then using vacuum preloading method respectively comparativing test model respectively for soil after flocculation and soil without flocculation.Detailed how to use flocculation-vacuum preloading strengthening newly hydraulic filling mud land base in a large area in the process of construction project site of dredger fill.It plays a guiding role for the application of the method in engineering practice.According to the monitoring data and the final test results,we have once again proven flocculation-vacuum preloading can effectively improve the hydraulic filling mud land base reinforcing effect.