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废旧轮胎胶粉用于填埋场衬垫材料改性,是提高衬垫系统有效性和扩展废旧轮胎资源化利用途径的一种手段。以高岭土作为黏性土的代表,开展废旧轮胎胶粉-高岭土混合土的力学和水力学性质试验,重点探讨胶粉掺量及尺寸对混合土渗透性、压缩性和收缩性的影响规律。研究表明,废旧轮胎胶粉-高岭土混合土的渗透系数、压缩系数、回弹指数、固结系数和体缩率等均随胶粉掺入比的增加而增大。高岭土及混合土的无侧限抗压强度大于200k Pa,50k Pa和200k Pa压力下渗透系数满足≤1.0×10~(-7)cm·s~(-1)的要求,均属于中压缩性土,且体缩率小于体积应变合格值4%。与30目胶粉相比,12目胶粉-高岭土混合土压缩性和回弹量较小、固结系数较大,胶粉尺寸对无侧限抗压强度、体缩率和渗透系数的影响不显著。在本文试验条件下,为提高黏土衬垫对有机污染物的吸附能力并满足渗透性、强度及变形的要求,12目25%胶粉改性黏土可作为填埋场黏土衬垫材料。
Waste tire rubber powder for landfill liner material modification is to improve the effectiveness of the liner system and expand the utilization of waste tires as a means of recycling. With kaolinite as the representative of cohesive soil, the mechanics and hydraulics properties of waste tire-kaolin mixed soil are tested. The influences of dosage and size of powder on the permeability, compressibility and shrinkage of mixed soil are discussed emphatically. The results show that the permeability coefficient, compressibility coefficient, rebound index, consolidation coefficient and shrinkage rate of waste rubber-kaolin mixed soil increase with the increase of the mixing ratio of rubber powder. The unconfined compressive strength of kaolin and mixed soil is greater than 200kPa, the permeability coefficient of 50k Pa and 200k Pa satisfies the requirement of ≤1.0 × 10 -7 cm · s -1, Soil, and body shrinkage rate of less than 4% of the value of the volume strain. Comparing with the 30 mesh powder, the compressibility and rebound of the 12 mesh powder-kaolin clay are smaller, the consolidation coefficient is larger, and the influence of the size of the powder on the unconfined compressive strength, the shrinkage rate and the permeability coefficient Not obvious. Under the experimental conditions in this paper, 12-mesh, 25% rubber-modified clay can be used as a liner material for landfill clay in order to improve the adsorption capacity of clay liner to organic pollutants and to meet the requirements of permeability, strength and deformation.