UAV-based Underground Digital Photogrammetry for Geotechnical Characterization of Fractured Rock Masses

准确的地质和岩土工程信息，特别是岩石裂缝的方向，对于设计安全的地下洞口至关重要。由于岩土技术数据不足，被称为“采场”的大型不规则矿山开口特别容易坍塌，但由于进入通常不安全，并且由于其他可用工具（激光雷达和地面摄影测量）的限制，准确的数据很少。随着无人驾驶飞行器（称为uav，或无人机）的最新进展，如果能够克服与照明、飞行控制和图像地理参考相关的挑战，基于uav的数字摄影测量有可能允许对这些大型、无支撑的地下开口进行高质量的岩土工程表征。本研究将解决这些问题，并将进行一系列室内和现场试验，以对该系统进行试点测试。这项研究的结果有可能通过提高采矿和地下建筑行业的安全性来造福社会，并在各种其他领域有潜在的应用，从灾难响应（检查倒塌或受损的建筑物），到封闭空间（洞穴，储罐，船舶等）的探索和敏感历史建筑的记录。该项目的主要目标是开发一种基于无人机的数字摄影测量系统，作为一种工具，用于对难以进入的地下（无照明）场地进行岩土工程表征。该系统将能够捕捉到高质量的照片（光线充足，不模糊），并有足够的重叠来提供立体覆盖。这需要组装一架无人机，它可以携带设备来拍摄图像，以及所需的照明和电池，并且可以被引导到精确控制的位置。可能研究的选项包括视频与静止图像，环境与闪光灯，以及有人驾驶与自主制导系统。此外，需要一些控制点来从一组照片中建立地理参考3D模型；还将制订和试验建立这些控制点的制度。该系统将在蒙大拿理工大学校园的室内空间和附近地下矿井的现场进行测试。室内和地下空间的三维模型的准确性，包括在现场岩体中裂缝的方向，将被量化。该项目将为PI和学生提供与采矿业代表以及NIOSH斯波坎研究实验室（专注于矿山安全和健康研究）人员互动的绝佳机会。它还将为地质工程系的研究人员建立基础设施，为涉及无人机数据收集的未来研究项目做出贡献，并为参与这项研究的学生提供最先进的技术。

Accurate geologic and geotechnical information, particularly orientation of rock fractures, is critical for the design of safe underground openings. Large, irregular mine openings known as "stopes" are particularly susceptible to collapse due to inadequate geotechnical data, but accurate data are scarce because access is often unsafe, and because of the limitations of other available tools (LiDAR and ground-based photogrammetry). With recent advances in unmanned aerial vehicles (known as UAVs, or drones), UAV-based digital photogrammetry has the potential to allow high quality geotechnical characterization of these large, unsupported underground openings if the challenges associated with lighting, flight control, and image georeferencing can be overcome. This research will address these issues, and a suite of indoor and field experiments to pilot test the system will be conducted. The results of this research have the potential to benefit society by enhancing safety in the mining and underground construction industries, and have potential application in a wide variety of other fields ranging from disaster response (inspection of collapsed or damaged buildings), to exploration of enclosed spaces (caves, storage tanks, ships, etc.) and documentation of sensitive historic structures.The primary goal of this project is to develop a UAV-based digital photogrammetry system to be used as a tool for geotechnical characterization of inaccessible underground (unlit) sites. The system would be able to capture good quality photos (well-lit, not blurry) with adequate overlap to provide stereo coverage. This requires assembly of a UAV that can carry the equipment to take the images as well as the required lighting and batteries, and that can be guided to precisely controlled locations. Options that may be investigated include video vs. still images, ambient vs. flash lighting, and piloted vs. autonomous guidance systems. Additionally, a number of control points are required to establish a georeferenced 3D model from sets of photos; a system for establishing those control points will also be developed and tested. The system will be tested in indoor spaces on the Montana Tech campus and in the field at a nearby underground mine. The accuracy of the 3D models of the indoor and underground spaces, including orientations of fractures in the rock mass at the field site, will be quantified. The project will provide excellent opportunities for the PI and students to interact with representatives from the mining industry, and with personnel from the NIOSH Spokane Research Laboratory (which is focused on mine safety and health research). It will also establish the infrastructure for researchers in the Department of Geological Engineering to contribute to future research projects involving UAV-based data collection, and for the students involved in this research to have access to this state-of-the-art technology.