溜砂坡的形成诱发因素及失稳破坏条件

通过对溜砂坡形成条件和诱发因素的分析,得出溜砂坡形成的3个必备条件是物质条件、地形条件和堆积条件;溜砂的主要诱发因素是地表水、地下水、河流冲刷、动荷载作用、风荷载作用、冻融作用、植物及人为因素。对溜砂坡砂样进行有关物理与力学试验,得出溜砂坡的粒度成分以中、粗砂和角砾为主;内摩擦角总体上是烘干状态大于天然状态,天然状态又大于饱和状态;粘聚力则呈现出天然时的大于饱和时的,而饱和时的又大于烘干时的规律。通过模型试验和理论分析,将双因素方差分析原理运用到砂粒粒径、含水量对溜砂坡天然休止角大小的影响分析中,结果说明这2种因素对溜砂坡天然休止角的影响都很大,并且含水量因素对天然休止角的影响,与砂粒粒径因素相比要大得多。运用线性回归理论对砂粒粒径、含水量、内摩擦角以及粘聚力等4个影响砂坡天然休止角的因素进行线性拟合,所得到的公式可用于天然休止角大小的估算。

The Inducing Factors and the Collapse Conditions of Sand-Sliding Slope

The forming conditions and inducing factors of sand-sliding slope are analyzed.The three necessary conditions to form sand-sliding slope are material conditions,terrain conditions and deposition conditions.The primary inducing factors of sand-sliding are surface water,ground water,stream erosion,dynamic load action,wind load action,freezing-and-thawing action,plant and man-made factors.By carrying through physical and mechanical test of sand-sliding samples,granularity composition of sand-sliding,which mainly made up of medium sand, coarse sand and talus debris are found.In drying state,the internal friction angle of sand-sliding is generally larger than that in natural state.The internal friction angle in natural state is larger than that in saturation state.While its cohesion in natural state is larger than that in saturation state,and the cohesion in saturation state is larger than in drying state.Through model test and theoretical analysis,the paper analyzes how sand grain and water content influence the natural repose angle of sand-sliding by applying double factors variance analysis.Results indicate that both factors have great effect on it.Compared with sand grain factor,water content has larger influence on the natural repose angle of sand-sliding.At last,linear fitting is conducted for four factors,which affect the natural repose angle of sand-sliding slope,like sand grain size,water content,internal repose angle and cohesion by using linear regression theory.The obtained formula can be applied to the estimation of the natural repose angle of sand-sliding slope.