高陡边坡岩体结构信息无人机识别与离散元数值模拟

IDENTIFICATION OF ROCKMASS DISCONTINUITIES AND 3D DISCRETE ELEMENT MODELING OF HIGH SLOPE BASED ON UNMANNED AERIAL VEHICLE PHOTOGRAMMETRY

岩体结构特征的准确表征对边坡稳定性评价具有重要影响。由于高陡边坡岩体结构的人工编录工作开展困难,结构几何信息往往获取不全面,导致边坡数值模型构建往往不理想。以江西德兴银山铜矿露天边坡为工程背景,采用无人机与运动恢复结构法(SfM)获取边坡岩体点云模型。基于点云数据建立结构面识别和解译算法,自动获取结构面产状、迹长、间距等几何信息。对比人工测量结果,无人机测量与结构面识别能够获取更符合实际的坡面与岩体结构模型。采用非均匀有理B样条(NURBS)曲面重构和“Rhino-Griddle-3DEC”联合建模方法,结合岩体结构统计模型构建离散裂隙网络DFN能够快速建立三维离散元数值模型,从而获得更好的数值模拟计算结果,满足岩质高边坡稳定性评价的需要。

Quantitative characterization of rockmass discontinuities has significant impact on the evaluation of slope stability.Considering the situation of the complex terrain and the difficulty of manual measurement at high and steep rock slope,unsatisfactory slope model construction affects the accuracy of slope stability analysis.This paper presents a field application on Yinshan open-pit copper mine in Dexing,Jiangxi Province.3D point cloud model is first generated based on unmanned aerial vehicle(UAV)photogrammetry integrated with a structure from-motion(SfM)technique.An automatic procedure for discontinuity detection,digital trace mapping and discontinuity parameters is established.The parameters include the orientation,number of sets,trace length,and set spacing.The extracted values are compared with planned manual measurements through scanline method.The results show that the slope shape and the rockmass model obtained by the UAV photogrammetry are more in line with the actual rock slope.The discrete fracture network(DFN)is established based on the statistic model of rockmass.Then a 3D numerical model is quickly built using non-uniform rational B-spline(NURBS)surface reconstruction and a combined modeling method of"Rhino-Griddle-3DEC".And better numerical simulation results are obtained to meet the demands of open pit mine slope stability analysis.