复杂水工边坡稳定性研究方法探讨

在天然边坡中进行开挖、建造水工建筑物等人类活动,扰动了边坡原有的稳定性,改变了边坡原有的结构,形成更为复杂的水工边坡。水工边坡的稳定性直接关系到水工建筑物的安全,甚至会影响水电工程的安全建设与正常运行。分别采用刚体极限平衡法和有限单元法,对某水电站调压井边坡进行了二维和三维稳定分析。研究结果表明:对于这类有竖井开挖的水工边坡,研究其稳定性时,需进行三维稳定分析;若对这类有竖井的边坡进行二维稳定分析时,应考虑剖面选取的位置,需要综合研究穿过竖井的剖面及竖井周围剖面边坡的稳定性,如果只选取穿过竖井的剖面,则其研究结果往往会与实际出现较大的偏差,使得实际稳定性较好的边坡得出不稳定的结论。研究成果可为此类复杂水工边坡的稳定性分析提供参考。

Simulation analysis on three-dimensional slope failure under different conditions

The failure mechanism of two-dimensional（2D） and three-dimensional（3D） slopes were investigated by using the strength reduction method.An extensive study of 3D effect was conducted with respect to boundary conditions,shear strength and concentrated surcharge load.The results obtained by 2D and 3D analyses were compared and the applicable scope of 2D and 3D method was analyzed.The results of the numerical simulation show that 3D effect is sensitive to the width of slip surface.As for slopes with specific geometry,3D effect is influenced by dimensionless parameter c/（γHtanφ）.For those infinite slopes with local loading,external load has the major impact on failure mode.For those slopes with local loading and geometric constraints,the failure mode is influenced by both factors.With the increase of loading length,boundary condition exerts a more significant impact on the failure mode,and then 2D and 3D stability charts are developed,which provides a rapid and reliable way to calculate 2D and 3D factor of safety without iteration.Finally,a simple and practical calculation procedure based on the study of 3D effect and stability charts is proposed to recognize the right time to apply 2D or 3D method.

霍林河南露天煤矿北区东帮控制开采方案研究

针对霍林河南露天煤矿北区东帮存在的边帮压煤问题,基于极限平衡及强度折减理论,从控制边坡稳定性的角度出发,结合南露天煤矿北区东帮边坡工程实际,依据煤层开采与内排土场、老滑体、断层的相对位置,提出了不同分区下以“横采内排、追踪压帮”为主的控制开采方案,采用数值模拟的手段分析了横采内排追踪距离对边坡稳定性的影响,优化设计了霍林河南露天煤矿北区东帮内排土场及横采工作帮边坡形态。研究结果表明:霍林河南露天煤矿北区东帮边坡滑坡模式以24煤底板弱层为底界面的切层-顺层滑动;霍林河南露天煤矿北区东帮边坡稳定性随内排与横采工作帮坡底的追踪距离增大呈负指数降低,当内排追踪距离50 m时,可充分利用边坡三维效应回收压覆的煤炭资源。