露天矿含弱层边坡三维危险滑面构建及稳定性计算

Three-dimensional dangerous sliding surface of slopes with a weak layer in open pit construction and stability calculation

露天矿含弱层边坡稳定性分析是露天开采领域中的一个重要研究内容,实际工程问题复杂多样,基于二维计算会导致结果偏于保守,有时无法满足复杂工程的需要,因此,开展含弱层边坡三维稳定性分析的研究是很有必要的。基于标准椭球,对其进行空间几何变换,与边坡插值生成一种由x_(a)等6个参数控制的椭球危险滑面,将椭球滑面与弱层结构面进行组合插值,构建含弱层边坡三维危险滑面;使用三维剩余推力法和遗传算法计算边坡稳定性系数并进行最危险滑面搜索,使用经典算例对方法进行验证,发现含弱层边坡随着滑体宽度增加稳定性系数逐渐降低。以锡林浩特某露天矿为应用实例,对东北帮含弱层边坡进行三维稳定性计算,验证了方法在实际工程中的适应性。

To solve the problem of three-dimensional stability analysis of slopes with weak layers in open-pit coal mines,we propose a method for constructing dangerous sliding surfaces of slopes with weak layers.Through spatial geometric operations such as rotation and translation of the standard ellipsoid,and slope interpolation,a dangerous sliding surface of the ellipsoid slope controlled by six parameters including the three semiaxes R_(a),R_(b),R_(c),sliding point x_(a),sliding point x_(b) and rotation angle θ of the ellipsoid is generated,and then,according to four different conditions,the dangerous sliding surface of the ellipsoid slope and the structural surface of the weak layer are selected and combined with interpolation to construct a three-dimensional dangerous sliding surface of the slope with the weak layer;Based on the basic principle of residual thrust method,a three-dimensional residual thrust method calculation program is compiled to calculate the slope stability coefficient,and genetic algorithm is used to search the most dangerous sliding surface;The method is verified by using classic calculation examples.The sliding mass width is 5 m,15 m,30 m,and 50 m respectively for calculation.The three-dimensional stability calculation results are 2.358,1.877,1.754,and 1.715 respectively,and the two-dimensional residual thrust method calculation results are 1.517.It is concluded that the stability coefficient of slopes with weak layers gradually decreases and gradually approaches the two-dimensional calculation results as the sliding mass width increases;Taking an open-pit coal mine in Xilinhot,Inner Mongolia Autonomous Region as an application example,the method was applied to establish a three-dimensional model of the slope with weak layers in the northeast side of the open-pit coal mine.The landslide mode was determined to be the combined sliding with the 1-1^(#)coal roof as the weak layer.The three-dimensional stability of the study area was calculated,and the calculation result was 1.321.There were five different lithologies in the sliding mass,and a total of 5425 rock blocks were generated to verify the adaptability of the method in the actual project.