基于正交试验的溜砂坡休止角分析

Slope Angle Analysis of Sand-sliding based on Orthogonal Experiment

拉萨地区溜砂坡分布广泛,随着近年来拉萨市的扩建,溜砂坡灾害的威胁程度不断加剧。文章以拉萨市主要交通干线沿线典型溜砂坡灾害点为研究对象,通过室内试验并根据土工规范选取出冻融、含水量、粒组3个因素的最不利变量,结合正交试验得出,在冻融、含水量、粒组3个因素共同作用下,粒组对溜砂坡休止角影响显著。溜砂坡休止角随不同粒组的缺失表现出不同特征：细砂、粉砂单独存在或起控制作用时休止角普遍较高;随粗、中砂所占比例增大并起骨架作用时,休止角呈下降趋势。据此可通过调查,建立拉萨地区溜砂坡天然休止角的趋势图,为溜砂坡的预测和防治提供依据。

Vast land in Lhasa is covered by sand-sliding.With the expansion of Lhasa city in recent years,the threat of sand-sliding disaster increases.In this paper the typical sand-sliding locations on the main transport arteries in Lhasa are taken as study object,the most unfavorable variables of freezing and thawing,water content,particle-size are selected by laboratory experiment and geotechnical specifications.After orthogonal experiment,it is drawn that particle-size significantly affects the angle of repose of sandsliding under the collective effect of freezing and thawing cycles,water content and particle-size.The angle of repose presents different features with lack of different particle size：the angle of repose is generally larger when fine sand exist on its own or controlling,and the angle of repose decreases with particle size increase or acting as framework.The sand-sliding trend chart can be developed after investigation on this basis which can provide reference for prevention and treatment of sand-sliding slope.