220kV盐津变电所北部边坡变形机制分析

该填土边坡位于云南省盐津县,场地岩土层主要由人工填土、耕植土和粉质粘土等第四系松散堆积层,以及全-强风化泥岩和中-微风化细砂岩等下伏基岩组成。全-强风化泥岩呈紫红色,岩质软弱,具有遇水软化成泥且强度迅速降低的特点。经过2d的强降雨之后,该填土边坡开始蠕滑变形,从地形地貌、地层岩性、地质构造、水文地质条件等场地条件和人类活动等方面对边坡的变形机制进行了分析。结果表明:边坡变形特征是一种推移式蠕滑变形,场地平整填方加载是造成边坡变形的诱发因素,不良的地形地貌、地质结构和地下水条件是导致边坡蠕滑变形的内在因素。

DEFORMATION MECHANISM OF THE NORTHERN SLOPE AT A TRANSFORMER SUBSTATION IN YANJIN, NORTHEASTERN YUNNAN PROVINCE

At a transformer substation in northeastern Yunnan Province, a slope was filled for sufficient constructing areas. The fill slope was composed of Quaternary accumulative formation and underlain Triassic detrital rock. The materials of the upper layer were predominated with accumulative formation such as landfill, gardening soil and silty clay The upper layer was underlain by a thin layer composed of completely to highly weathered mudstone. It was prone to become softer and its strength could be reduced significantly when moisturized. The lower layer was composed of packsand. After a period of heavy rainfalls, the fill slope started to creep and deform, which threatened the safety of the transformer substation, dead end tower of 110 kv output power. This paper described the geological environmental background of the northern slope on the 220kV Yanjin transformer substation. It further presented a detailed analysis of deformation mechanism through field investigation and laboratory testing. The slope deformation was probably caused by a combination effect of unfavorable topographic, geological and hydro geological conditions, and external loading due to filling. It was concluded that the creep deformation of the slope was triggered by external loading applied at the back of the slope.