膨胀土边坡防护机理分析及防护方法比较

Analysis on Protection Mechanism and Comparison on Protection Methods for Expansive Soil Slope

膨胀土是一种广泛分布的难处理的问题土。膨胀土边坡容易发生失稳破坏,要找到最佳的防护方法,需要从其破坏机理着手。总结失稳机理的已有研究成果,指出膨胀土边坡具有区别于一般黏性土边坡的特殊破坏机理,主要在于膨胀土的裂隙性,需要特殊对待。对膨胀土边坡的特殊防护机理进行了分析,主要为通过控制边坡水分变化来限制土体裂缝开展。按照防护机理的不同,将现有的膨胀土边坡防护方法分为两类:限制裂缝开展和不限制裂缝开展,前者包括土工膜法、换填法和化学改性法等,后者包括支挡结构法、坡面防护法、土工袋法和物理改良法等。对这些防护方法进行了具体的分析和比较,以供工程运用选择作参考。对膨胀土边坡防护方法的设计给出了建议。

Expansive soil is a kind of widely distributed and hard treated trouble soil. Slope failure may often occur in expansive soil. The best slope protection method of expansive soil slope can only be found, if the failure mechanism is consid- ered. Existing research results of slope failure mechanism for expansive soil is summarized in this paper, and the special slope failure mechanism distinguished expansive soil from common cohesive soil is proposed, which is the crack developed in expan- sive soil, so special attention should be paid to it. The protection mechanism of expansive soil slope is analyzed, which is con- trolling slope soil water and limiting crack development. According to the difference in protection mechanism, existing expan- sive soil slope protection methods can be classified to two categories： limiting crack developing methods and non-limiting crack developing methods. The former includes geomembrane method, replacement method, chemical modified method and so on. The latter includes supporting structure method, surface protection method, soilbag method, physical improvement method and so on. Specific analysis and comparison is made for expansive soil slope protection methods, which can be as a reference in engi- neering application. In the end, suggestions are proposed for slope protection methods designing of expansive soil.