Seal Mechanism And Deformation Law Of Compacted Clay Polluted By Cd

In recent years, Cd polluted soil become a major environmental problem. Cement solidification is considered to an effective means to achieve safe disposal. Through indoor microstructure tests to analyze the evolution of morphology and pore structure of cement solidification Cd polluted clay in curing process. Use specification of soil tests to study the effects of deformation characteristics. Through cracking and penetration tests study the laws of cracked and permeable in wet and dry cycle. Use contaminants leaching tests to study the law of Cd contamination release. This study has great value of cadmium polluted clay harmless treatment and resource utilization. Based on the tests and theoretical analysis, the main conclusions are as follows:(1) The maximum porosity rate of cement content were0%,2%,5%,8%and10%of the solidified Cd polluted clay were0.91,0.29,0.16,0.11and0.07cm3/g·nm, and the maximum incremental pore volume peak appeared at the aperture were6.79,4.78,3.55,3.15and2.95nm, indicating that with the increasing of cement content, the pore size and pore volume decreased. And the specific surface area of soil particles decreased.(2) After Cd polluted clay cement curing period reached14days, the concentration of Cd leaching pollutants reached steady state; the maximum contaminant leaching of2%,5%,8%and10%cement content were1.3mg/L,0.75mg/L,0.09mg/L and0.08mg/L; basis to meet the national standards, the cement content of5%was more economical and practical.(3) Pore volume decreased after hydration; Cd pollutants increasing with pore size. Cement content of2%and5%was first rapid released and then raised slowly; Cement content of8%and10%was stepped raised.(4) The unconfined compressive strength and shear strength of Cd polluted clay has been significantly improved by cement solidification. The maximum unconfined compressive strength was139.83、241.08、346.96、510.67and682.50kPa, and the cohesion force and internal friction angle of the clay decreased. The compression coefficient was reduced, and the compression modulus increased rapidly, that the strength of the clay was increased.(5) For the degree of compaction was1.60g/cm3, the best dosage of cement stabilized soil was8%in the wetting-dry ing cycle, with the smallest cracking factor of0.0185; after4times cycle the role of stabilized soil permeability appeared significantly improved, increase of1to2orders of magnitude. The permeability of degree of compaction1.60g/cm3and cement content of8%increased1order of magnitude.