成贵铁路高山田巨型古滑坡成因分析及地质选线-《高速铁路技术》

文章信息/Info

Title:: Cause Analysis and Geologic Route Selection for Gaoshantian Giant Fossil Landslide of Chengdu-Guiyang Railway

Author(s):: WANG Fuping; YE Kun; YUE Zhiqin; China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, China

Keywords:: fossil landslide|thrust load caused landslide|limit equilibrium method|geological route selection|terrace

摘要:: 高山田古滑坡规模巨大，是上下均为阶地、中间为滑坡体的三层结构，形态极为特殊复杂。通过综合野外地质调绘、现场钻探等勘察手段，详尽查明了滑坡体的工程地质特征，包括滑坡边界、分布形态、滑床埋深、滑体岩性特征、滑体组成及厚度、主滑方向等。本文在此基础上对滑坡成因进行了分析，采用极限平衡法综合计算了滑坡体的C、φ值，并对滑坡体的下滑力、抗滑力进行了计算，判定了滑坡体自然稳定性和工程稳定性。研究结果表明：高山田古滑坡属于阶地型巨厚层岩质推移式巨型滑坡，该滑坡目前处于稳定状态，但隧道开挖易引起古滑坡局部复活，施工安全风险极大，地质选线时采取了绕避滑坡的方案。本研究可供复杂山区河流阶地斜坡勘察借鉴。

Abstract:: Gaoshantian fossil landslide,which covers a large scale, has a very special and complex form of three-layer structure including the upper and lower levels of terraceand the middle layer of the landslide mass. By using the geological prospecting methods like geological mapping and field drilling, the engineering geologicalcharacteristics of the landslide mass are ascertained, including landslide boundary, distribution pattern, depth of sliding bed, lithologic character, component and thickness of landslide mass, main sliding direction, etc. On this basis, the landslide causes are analyzedin this paper, C and φ value, sliding force and sliding resistance force of the landslide mass are calculated with limit equilibrium method, and then, the nature stability and engineering stability of landslide mass are determined. The results show that Gaoshantian fossil landslide belongs to giant terraced push type thick layer rocklandslide, which is now stable but could be easily resurged by tunnel excavation, and there is a high risk for construction. The scheme of by passing the landslide is suggested geological route selection. The study provides reference to the investigation work of river terraceslopes in complex mountain area.