Abstract: Under the long-term hydraulic effect after dam completion, some problems easily arise, such as cracks in the dam body, corrosion of the metal structure, scouring pit downstream of the dam, etc. Most of these problems are underwater and not easy to be discovered, posing a threat to the project safety. Due to the limitation of diving time and depth, the traditional underwater inspection by frogman can only inspect key parts, and it is difficult to carry out health inspection in a large area of the reservoir. In addition, due to the complexity of underwater environment, the safety risk and cost of underwater inspection by frogman are higher. In this paper, the technology of multi-beam combined underwater vehicle is used to inspect trash rack at intake and the scouring pit of the stilling basin of spillway. By inspection, the integrity, metal corrosion and surface debris deposition of the trash rack are identified, and the high precision data of the scouring pit in stilling basin are obtained. This technology breaks through the limits of the scope of underwater inspection, improves the work efficiency while ensuring the safety of personnel, and provides reliable data for the repair of underwater defect, which can provide reference for similar projects.

Key words: underwater inspection, multi-beam, unmanned underwater vehicles, underwater image, underwater terrain

摘要： 大坝建成后在水力的长期作用下，坝体易出现裂缝，金属结构易锈蚀，大坝下游易出现冲坑，这些问题往往都隐藏在水下，不易被发现，给工程安全造成威胁。传统的蛙人水下检查技术受下潜时间和下潜深度的限制，作业范围有限，只能对关键部位进行检查，难以对水库大范围区域进行健康检查，另外由于水下环境的复杂性，蛙人在水下作业时会有生命危险，采用蛙人进行水下检查的费用也较高。采用多波束联合水下机器人的作业方式对某枢纽进水口拦污栅和溢洪道消力池冲坑进行水下检测，探明了拦污栅结构的完整性、金属锈蚀及表面杂物淤积情况，测量得到了消力池冲坑的高精度数据。该技术突破了水下检查作业范围的限制，在保证人员安全的情况下，提高了工作效率，给指导大坝水下缺陷修复提供了可靠的数据支撑，可为同类工程提供借鉴。

关键词: 水下检查, 多波束, 水下机器人, 水下图像, 水下地形