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膨胀土吸水体积膨胀,失水体积收缩的特性,给工程建设带来的危害屡见不鲜。因此如何改良膨胀土,显得尤为突出。化学改良法是膨胀土改良的常用手段之一。电石渣是工业制乙炔的主要废弃物,其堆放不仅占用大量土地,而且会造成环境及地下水污染等。通过系统的室内试验,探讨利用电石渣改良膨胀土的方法,掌握电石渣改良膨胀土的物理、力学性质及胀缩性特征。试验结果表明:随电石渣掺量的增大,改良土的最优含水率逐渐增大,最大干密度逐渐降低;塑性指数随电石渣掺量的增大先增大后降低;改良土的自由膨胀率、膨胀量、膨胀力与线缩率均随着养护龄期的增长呈减小趋势;随养护龄期的增长,改良土的压缩模量呈增大趋势,压缩系数呈减小趋势;改良土的抗剪强度随养护龄期增长主要体现在黏聚力、内摩擦角及无侧限抗压强度均随养护龄期的增长而增大;通过试验得到电石渣改良膨胀土的最优掺量为10%。扫描电镜的结果也验证了随养护龄期的增长,改良土的强度增大,胀缩性减弱。
Expansion of soil water absorption volume expansion, shrinkage of the characteristics of water loss, to the construction of the hazards are not uncommon. Therefore, how to improve the expansive soil is particularly prominent. Chemical modification method is one of the common means of expansive soil improvement. Calcium carbide slag is the major waste of industrial acetylene, which not only occupy a large amount of land, but also cause environmental and groundwater pollution. Through the systematic indoor experiment, the method of using carbide slag to improve expansive soil is discussed, and the physical, mechanical properties and expansibility of expansive soil are improved. The results show that with the increase of carbide slag content, the optimum moisture content of modified soil increases gradually and the maximum dry density decreases gradually. The plasticity index increases firstly and then decreases with the increase of carbide slag content. With the increase of curing age, the compressive modulus of the improved soil shows an increasing trend while the compressibility shows a decreasing trend. With the increase of curing age, The shear strength of modified soil increases with curing age mainly in the cohesion, internal friction angle and unconfined compressive strength increase with the curing age. Through the experiment, the optimum of carbide slag modified expansive soil The dosage is 10%. The results of scanning electron microscopy also verified that with the increase of curing age, the strength of modified soil increased and its shrinkage reduced.