膨胀土边坡防护方案比选研究

Comparison study of four protection schemes for expansive soil slope

针对膨胀土边坡的防护问题,对土工膜、砂垫层、表砂层和水泥改性土4种防护方案进行室内模型试验,在膨胀土模型边坡干湿循环工况下,对比每种方案下模型边坡的膨胀变形、裂隙开展和含水率变化情况,讨论了各方案的防护效果及工程应用问题。结果表明:4种防护方案中,水泥改性土方案的防护效果最优;采用土工膜方案时应注意土工膜间的搭接处理;采用砂垫层方案时应根据气候条件确定合理的砂垫层厚度;表砂层方案不宜单独使用,可作为辅助措施;采用水泥改性土方案时,在保证防护层厚度的基础上应注意控制其压实度并做好养护工作。

With the aim of protecting expansive soil slope,four kinds of protective schemes were chosen for laboratory model tests,including geo-membrane covering,sand cushion bedding,sand layer covering,and replacement with cement-treated soil. Drying-wetting cycles were carried out for slopes with different protective methods. During the cycles,the deformation of expansion,the development of cracks,and the variation of moisture content were monitored and compared among these slope models. The effectiveness of each protective method and corresponding application problems were discussed. The results show that the method of replacement with cement-treated soil is the best of these four methods. Furthermore,for geo-membrane, attention should be paid to processing the joint between two pieces of geo-membrane. For the method of sand cushion bedding, the thickness of the sand cushion should be adjusted according to the climate conditions. The sand layer covering should be taken as a supplementary measure rather than being used independently. When the method of replacement with cement-treated soil is used, attentions should be paid to guaranteeing the thickness, controlling the degree of compaction, and doing careful maintenance work.