Performance Of Ground Rubber Amended Soil-bentonite Backfills

Soil-bentonite is widely used as cutoff wall materials due to its advantages including easily construction,low cost and permeability coefficient.However,it is difficult for soil-bentonite to resistant to chemical corrosion,which may change its consolidation and permeation.Thus,its practicality and reliability may be affected.In order to enhance the adsorption capacity of cutoff wall,soil-bentonite modified with ground rubber was used as subject,whose basic physical properties,mechanical properties and adsorption were studied and whose retardation ability for contaminants was evaluated.The result will be helpful to improve the effectiveness of the project such as the waste sanitary landfill and contaminated site,and helpful to improve the utilization ratio of waste tire.(1)Slump text and liquid as well as plastic limit test was carried out.The water content of 110 mm slump was determined.The regulation between slump and the mix ratio of rubber as well as the liquid limit of mixed soil was evaluated.the ratio of bentonite which may meet the requirements of the slump was also determined.(2)One-dimensional consolidation text was carried out to analyse the influence of simulated leachate,oil pollution and powder characteristics on consolidation.(3)Under the circumstance of being contaminated by simulated leachate and lubricating oil,the variation range of hydraulic conductivity(k)of soil-bentonite amended with ground tires was evaluated by permeability test compared with the k obtained from consolidation test.The material which may meet the requirement on k would be established.(4)The adsorption ability of rubber,bentonite and kaolin for phenol was studied by adsorption text by which distribution coefficient was earned.The transport regulation of phenol in soil-bentonite amended with ground tires was researched by column text by which retardation coefficient was obtained.The adsorption capacity of soil-bentonite amended with ground tires to the organic contaminants represented by phenol was evaluated.(5)Contaminant transport was calculated to study transport regulation of phenol in soil-bentonite amended with ground tires.Relative concentration and flux were used as standard to determine the breakdown time of cutoff wall.The factors which may affect the service life and quality of cutoff wall were analysed.Performance of cutoff walls under different earth pressures was discussed.