ABSTRACT

Lime is the oldest known traditional soil stabilizer, especially for clay soils. In the Hyrcanian forest in northern Iran, clay-textured soils are widespread and cause many problems for infrastructure development, particularly forest roads. Therefore, the current study investigated the stabilization effect of different percentages (5%, 7%, and 9% by weight) of lime on a typical clay with high plasticity. Laboratory tests were Atterberg limits, standard Proctor, and unconfined compressive strength (UCS) and were used to determine the extent of stabilization. Lime decreased the liquid limit and plasticity index, but increased the plastic limit. The greatest decrease in liquid limit and plasticity index was 48% and 94%, respectively, for the 9% lime treatment and the greatest increase in plastic limit was approximately 39% when 7% lime was added. Furthermore, the greatest decrease in maximum dry density was 5% with the 9% lime addition and the greatest increase in optimum moisture content was 9% when lime was added at both 5% and 7%. Lime treatments generally had a positive effect on soil compressive strength, except when added at the 7% rate. At 7% lime, compressive strength decreased as compared with the control soil. The best improvement in soil strength was achieved with 9% lime treatment; with a 39.45 kN/m² (6%) increase in the strength. Based on these laboratory findings, lime can improve the engineering properties of expanding clay soils in a forest road. However, further field studies are necessary to determine if the effects of our laboratory study are similar to road subgrades.

摘要

石灰是已知最古老的传统土壤稳定剂，尤其适用于粘土。在伊朗北部的希尔卡尼亚森林中，粘土质地的土壤很普遍，给基础设施发展带来了许多问题，尤其是森林道路。因此，当前的研究调查了不同百分比（按重量计 5%、7% 和 9%）的石灰对具有高塑性的典型粘土的稳定效果。实验室测试是 Atterberg 极限、标准 Proctor 和无侧限抗压强度 (UCS)，用于确定稳定程度。石灰降低了液限和塑性指数，但增加了塑限。9%石灰处理的液限和塑性指数的最大下降分别为48%和94%，而当添加7%石灰时，塑限的最大增加约为39%。此外，当石灰添加量为 9% 时，最大干密度的最大降低为 5%，当石灰添加量为 5% 和 7% 时，最佳含水量的最大增加为 9%。石灰处理通常对土壤抗压强度有积极影响，除非以 7% 的比例添加。与对照土壤相比，7% 石灰的抗压强度降低。9% 石灰处理对土壤强度的改善效果最好；39.45 kN/m 9% 石灰处理对土壤强度的改善效果最好；39.45 kN/m 9% 石灰处理对土壤强度的改善效果最好；39.45 kN/m² (6%) 强度增加。根据这些实验室发现，石灰可以改善林道中膨胀粘土的工程特性。然而，需要进一步的实地研究来确定我们实验室研究的效果是否与道路路基相似。