基于数字近景摄影测量的隧道围岩结构面产状自动提取方法研究

Study on automatic extraction method of structural plane orientation of tunnel surrounding rock based on digital close‐range photogrammetry

为了快速、准确地获取掌子面岩体结构面产状信息,提出了基于数字近景摄影测量技术的隧道掌子面岩体结构面产状的自动提取方法。通过拍摄多组隧道开挖面的图像,生成开挖隧道岩体表面的三维实体模型和点云模型,基于k-means++算法和DBSCAN(density-based spatial clustering of applications with noise)算法实现了掌子面点云法向量的自动分组与结构面圆盘拟合,通过计算结构面圆盘的法向量获得了结构面的产状。将该方法应用于朱家山公路隧道开挖面结构面倾向倾角的获取,研究结果表明:该方法可快速生成开挖隧道三维点云模型,能够非接触式地识别统计掌子面岩体的结构面信息,尤其适用于岩体破碎而技术人员接触测量有安全危险的掌子面,实现了隧道围岩结构面信息的自动提取。

In order to quickly and accurately obtain the occurrence information of rock discontinuity in tunnel face,this paper proposes an automatic extraction method of rock discontinuity occurrence in the tunnel face based on digital close-range photogrammetry.By photographing multiple groups of tunnel excavation face images,3D solid model and point cloud models of the excavated tunnel rock mass surface were generated.Based on the k-means++and DBSCAN(density-based spatial clustering of applications with noise)algorithm,the automatic grouping of the point cloud normal vector of the tunnel face and the fitting of the structural plane disk were realized.The occurrence of the structural plane was obtained by calculating the normal vector of the structural plane disk.The method was applied to obtain the dip angle and dip direction of the excavation face of Zhujiashan highway tunnel.The research results show that the method can quickly generate the three dimensional point cloud model of the excavation tunnel,and can non-contact identify and count the structural plane information of the tunnel face rock mass.It is especially suitable for tunnel faces where the rock mass is broken,which is dangerous for technicians to measure by contact,and the automatic extraction of structural plane information of tunnel surrounding rock can be realized.