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由泥岩和砂岩互层而构成软硬互层顺层边坡是甘肃省等西北地区分布较多的一种边坡形式,因工程建设需要而进行的削坡往往导致高陡边坡,进而引发崩塌等工程灾害。以甘肃古浪境内G312线界古公路十八里铺水库段典型砂岩和泥岩互层边坡崩塌为背景,通过分析现场崩塌形态与特征,将其归结为大型崩塌和小型崩塌两种类型;通过研究地形地貌特征,认为公路边坡具有“高”和“陡”的特点,为崩塌发育提供临空条件;通过分析气象和水文特征,认为较大的日温差、相对湿度日变化以及层间裂隙水的存在加剧了风化作用,集中降水则是崩塌产生的主要诱发因素;通过研究工程地质和地层结构特征,泥岩和砂岩显著的岩性差异和互层结构为崩塌提供了物质条件。其机理可概括为:干湿循环致泥岩风化、砂岩节理发育;集中降水诱发边坡崩塌。研究成果对西北地区高陡软硬互层边坡崩塌灾害的认识和防治具有参考价值。
The interbedded layers of mudstone and sandstone constitute the soft and hard interbed Stratified slope is a type of slope with more distribution in the northwestern region of Gansu Province. The slope cutting due to the construction needs often leads to high and steep slopes, Collapse and other engineering disasters. Taking the collapse of the interbedded slope of typical sandstone and mudstone in the Shibalilipu reservoir of G312 line of G312 line boundary in Gulang, Gansu Province as the background, the collapse patterns and characteristics of the site were analyzed and classified into two types: large-scale collapse and small-scale collapse. The features of topography and steepness of highway slopes are considered to study the features of topography and geomorphology, which provides the conditions for the avalanche development. By analyzing the meteorological and hydrological characteristics, it is considered that the daily diurnal variation and the relative humidity change And the existence of intercalary fissure water aggravate the weathering. Concentrating precipitation is the main inducing factor of the collapse. By studying the engineering geology and stratigraphic structural features, significant lithological differences of mudstone and sandstone and interlaminar structure provide the material conditions for the collapse . The mechanism can be summarized as follows: wet-dry cycle caused by mudstone weathering, sandstone joints development; concentrated precipitation-induced slope collapse. The research results have reference value for the understanding and prevention of collapse in high-steep hard-soft inter-layered slope in Northwest China.