| 基于地面三维激光扫描的三峡库区危岩体监测 |
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| 引用本文： | 褚宏亮,邢顾莲,李昆仲,王国利,段奇三.基于地面三维激光扫描的三峡库区危岩体监测[J].水文地质工程地质,2021,48(4):124-132. |
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| 作者姓名： | 褚宏亮 邢顾莲 李昆仲 王国利 段奇三 |
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| 作者单位： | 1.中国地质环境监测院（自然资源部地质灾害防治技术指导中心），北京 100081 |
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| 基金项目： | 三峡后续工作地质灾害防治项目（0001212018CC60008） |
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| 摘 要： | 三峡水库周期性蓄水改变了岸坡内的地下水渗流场和应力场，降低岩土体的剪切强度，对库岸边坡、岩体稳定性影响很大。以往库区岸坡岩体形变监测主要通过设置固定点进行观测，难以发现岩体整体变化情况。地面三维激光扫描方法能获取岩体整体表面厘米精度的点云数据，具有无需接触目标、获取速度快、精度高等特点，非常适合库区高陡危岩体表面三维形变监测。以巫山箭穿洞危岩体为例，采用地面三维激光扫描方法对箭穿洞危岩体进行了为期2年（2017—2018年）共3期监测，以第一期观测目标周围稳定岩体数据为基准，对数据进行重叠点云迭代配准，点云配准精度优于±2.7 cm。针对箭穿洞危岩体在观测时段内的变化情况，构建危岩体区域的基准不规则三角网模型，以点到基准面最近距离法结合危岩体变化区间分析其变形。通过对比分析箭穿洞危岩体3期观测数据，发现相对于2017年，2018年箭穿洞危岩体左侧岩体有变形趋势；在库区蓄水阶段，危岩体局部多处存在明显凹陷变化，局部因蓄水影响发生约?0.03～?0.07 m变形。结果证明三维激光扫描技术在库岸高陡边坡形变监测中的有效性，为三峡库区高陡危岩体形变监测及地质灾害防治工作提供了参考。
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| 关 键 词： | 地面三维激光扫描 三峡库区 危岩体 箭穿洞 变形监测 |
| 收稿时间： | 2020-08-15 |
Monitoring of dangerous rock mass in the Three Gorges Reservoir area based on the terrestrial laser scanning method |
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| Affiliation: | 1.China Institute of Geo-Environment Monitoring(Guide Center of Prevention Technology for Geo-hazards, MNR), Beijing 100081, China2.Geological Environment Monitoring Station of Tibet Autonomous Region, Lhasa, Xizang 850000, China3.School of Geomatics and Urban Spatial Information, Beijing University of Civil Engineering and Architecture, Beijing 102616, China4.Beijing Dijing Technology Co. Ltd., Beijing 101400, China |
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| Abstract: | Changes in water level of the Three Gorges Reservoir are easy to induce the deformation and failure of the reservoir slope. Periodic impoundment changes in the groundwater seepage field and stress field in the reservoir slope reduce the shear strength of rock and soil mass, and have a great impact on the stability of the reservoir bank slope and rock mass. It is urgent for the deformation monitoring of bank slopes in the reservoir area. It is difficult to find out the overall change of rock mass by setting fixed observation points, and the terrestrial laser scanning method (TLS) can obtain the point cloud data of the overall rock mass surface with centimeter accuracy, which is very suitable for the monitoring of rock mass of characteristics of no contact with the target, fast acquisition speed and high precision. In this paper, the terrestrial laser scanning method is used to monitor the dangerous rock mass of Jianchuandong in Wuxia county for two years (2017—2018) and three periods data are acquired. The stable rock mass data around the observation target of the first period is selected as datum and the iterative closest point registration (ICP) is carried out with the overlapping point cloud. The registration accuracy of the point cloud is better than ± 2.7 cm, which realizes the accurate alignment of multi-period data. According to the change of dangerous rock mass in the observation period, the datum TIN model of dangerous rock body area is constructed, and the deformation of dangerous rock mass is analyzed with the nearest distance method from point to reference surface combined with the change range of dangerous rock mass. Through the comparative analysis of the 3 periods observation data of the Jianchuandong dangerous rock mass, it is found that the dangerous rock mass has the expansion trend in 2018 compared with the left rock mass in 2017. In the reservoir water storage stage, there are obvious sag changes in some parts of the dangerous rock body, and the local deformation is about 30-70 mm due to the influence of water storage. The experiment proves the correctness and validity of the proposed monitoring method, which provides reference for the monitoring of dangerous rock state and the prevention and control of geological disasters in the Three Gorges Reservoir area. |
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