Experimental Study On Cracking Deformation And Triaxial Shear Of Sludge Ash Modified Clay Liner In The Landfill

To study the feasibility of the modified clay sludge ash as landfill liner,carry out the basic mechanical properties of modified clay sludge ash test,determine the maximum dry density of sludge ash modification of clay,the optimum moisture content value,expansion and shrinkage ratio,unconfined compressive strength;carry out sludge ash modified clay cracking deformation and permeability test,to study cracking deformation characteristic and microstructure of sludge ash modified clay under continuous drying and wetting drying cycles,and the permeability of sludge ash modified clay under drying and wetting cycle;carry out sludge ash modified clay triaxial shear test to study sludge ash modified clay shear strength characteristics,to determine the shear strength parameters(cohesion and internal friction angle)and comes to the conclusions as follows.(1)linear shrinkage rate of sludge ash modified clay decreases with the increase of sludge ash content,the range of linear shrinkage rate is 5.2% ~ 8.8%,inflation rate and the permeability coefficient increased with the increase of sludge ash content increased,inflation rate change in the range of 54.8% ~ 99.2%,the range of saturated permeability coefficient is 0.23×10-7cm/s~3.42×10-7cm/s,with the increase of sludge ash content,the unconfined compressive strength presents increase first and then decrease trend,the range of unconfined compressive strength is 458.3 kPa ~ 628.1 kPa;(2)with the increase of the content of sludge ash and dry wet cycling times increasing,cracking degree of sludge ash modification of clay is very serious,the changes range of cracking factors is 0.0198 ~ 0.1675,The specific surface area,pore volume,specific surface area changes in the range of 0.0053cm2/g~0.0283cm2/g,pore volume changes in the range of 0.273cm3/g~0.633cm3/g;(3)In the cyclic wetting drying,sludge ash modified clay permeability coefficient increase with the times of wetting and drying cycles increases,the range of permeability coefficient is 0.23×10-7cm/s~2.24×10-7cm/s,cracking factor and pore volume positive proportional growth with permeability coefficient;(4)with the content of sludge ash increased,sludge ash modified clay shear strength and shear strength parameters(cohesion,internal friction angle)increases at first and after decreases,and the sample of 3% sludge ash modified clay shear strength is maximum;the cohesion changes in the range of 46.85kPa~111.96 kPa,the internal friction angle changes in the range of 13.8°~25.1°.(5)The test results show that when the content of the sludge ash sample is controlled to 3%,the index is the best,and the feasibility of the material is high.