黄土沟壑基底排土场滑坡的空间演化机制

Spatial evolution mechanism of landslide in loess gully basement dump

外排土场是露天采矿的必然产物。由于特殊的地形地貌,我国中西部的一些露天煤矿将排土场建立在沟壑发育的黄土基底上,形成了基底软弱、形态极其复杂的黄土沟壑基底排土场,其稳定性将成为影响露天煤矿安全高效生产的重要因素。因此,为揭示黄土沟壑基底排土场变形破坏的空间演化规律,以准能公司黑岱沟排土场为工程背景,基于断续结构面理论和强度折减理论,并考虑起伏结构面的啃断与爬坡效应,分析了黄土沟壑基底和排土场的破坏机理;采用FLAC^(3D)数值模拟手段,研究了排土场变形破坏的空间演化过程,并通过分析黄土沟壑基底排土场和各剖面的最大位移云图及临界失稳时变形区位置,确定了黄土沟壑基底排土场的滑坡模式及滑坡区域。研究结果表明,黄土沟壑基底面可视为一起伏无充填结构面,在排土场载荷与剪切作用下会形成啃断与爬坡效应,即排土场将发生剪断部分凸起的非规则曲面滑坡;黑岱沟排土场易在排弃物载荷作用与沟壑基底形态的双重影响下,边坡上部岩体先发生变形,并挤压中、下部岩体发生变形,位于南北中轴线两侧的变形区向北部坡底扩展,形成类椭球形变形区,最终演化成推动式滑坡。研究结果可为黑岱沟排土场滑坡预警和边坡治理提供技术参考,为类似排土场边坡稳定性研究提供借鉴。

External dump is the inevitable outcome of surface mining.Because of the special landform,some open-pit coal mines in the middle and west of China build their dump sites on the loess base with gully development,forming the loess gully base dump with weak basement and extremely complex morphology.Its stability will become an important factor affecting the safe and efficient production of opencast coal mine.As a result,to study in Loess Gully basal dump deformation destruction of spatial evolution,in Heidaigou dump as an engineering background,based on discontinuous structural plane theory and strength reduction theory,considering the gnawing and climbing effect of undulating structural plane,the failure mechanism of loess gully basement dump was analyzed.Using FLAC^(3D) numerical simulation method,the spatial evolution process of the deformation and failure of the dump was studied,the landslide mode and landslide area of the loess gully basement dump were determined by analyzing the maximum displacement cloud map of each section and the position of the deformation zone during critical instability.The results show that the loess gully basement can be regarded as an undulation and unfilled structural plane,and the gnawing and climbing effect will be formed under the loading and shear of the dump,that is,the irregular surface landslide of the raised shear part will occur in the dump.T Under the dual influence of the dumping load and the morphology of the gully base,the upper rock mass of the slope deforms first,and then the middle and lower rock mass deforms under the extrusion.The deformation zones located on both sides of the north-south central axis extend to the Northern Slope bottom,forming a quasi-ellipsoid deformation zone,and finally evolves into a push landslide.The research results can provide technical reference for landslide warning and slope treatment of Heidaigou dump,and provide reference for slope stability study of similar dump.