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针对目前膨胀土改良措施中存在的问题,提出了一种新的改良方法——在膨胀土中掺入风化砂,对膨胀土实施物理改良。对风化砂不同掺入率的膨胀土进行颗分试验,液、塑限试验,活性指数试验,相对密度试验。试验表明:随着掺砂比例的增大,活性指数急剧下降,液性指数发生了降低;对风化砂不同掺入率改良膨胀土进行的自由膨胀率、有荷膨胀率、无荷膨胀率和膨胀力试验表明,随着掺砂比例的增加,膨胀土的膨胀性得到显著的抑制;最后对掺砂膨胀土进行了直剪试验、无侧限抗压强度试验、CBR试验和回弹模量试验,探讨不同掺砂率对强度指标的影响及其变化规律。试验研究结果表明,掺砂能较好地改良膨胀土的基本工程性质指标,有效抑制膨胀土的膨胀特性,改善膨胀土的力学强度性能,掺砂后膨胀土的各项指标均可达到路基填料的要求。
Aiming at the existing problems in the expansive soil improvement measures, a new improved method is put forward, in which the weathered sand is mixed with the expansive soil and the expansive soil is physically modified. Weathered granulation of different incorporation rates of expansive soil particle test, liquid, plastic limit test, activity index test, the relative density test. The results show that with the increase of the proportion of sand, the activity index drops sharply and the liquid index decreases. The free expansion rate, load expansion rate and un-load expansion rate Expansive force tests show that with the increase of sand content, the expansibility of expansive soil is significantly restrained. Finally, the direct shear test, unconfined compressive strength test, CBR test and elastic modulus Test to explore the effect of different sand content on the strength index and its variation. The experimental results show that sand-mixing can well improve the basic engineering properties of expansive soils, effectively restrain the expansive properties of expansive soils, and improve the mechanical strength of expansive soils. The indexes of expansive soils can reach the subgrade filling Request.