多波束测深结合声呐技术在河道堤防水下外观病害探测中的应用

Application of technique of multi-beam bathymeter combined with sonar to detection of exterior disease of river-embankment under water

针对河道堤防水面线以下的表观病害具有隐蔽性、难于探测和发现的特点,将多波束条带测深技术和双频识别声呐技术相组合,实现了准确布置计划测线确保水下外观病害全覆盖扫测。通过在双频识别声呐换能器上安置GPS接收机,基于位置信息将病害中心位置在多波束点云图上准确地标示出来,从而弥补了两种技术各自的局限性,并在工程实践中开展应用。实践表明,选择波束角小的多波束条带测深系统,可获取高质量、高分辨率的数据,便于发现细微的外观破碎、剥落等病害。在多波束扫测工作中船速不宜太快,应控制在5节以内,同时声呐探测时应平行水流方向布置测线。工程实例表明,将两种技术组合在一起,能准确发现水下破损、塌陷等表观病害。研究成果为类似工程的病害探测和除险加固提供技术支撑。

In accordance with the characteristics of the exterior diseases of fiver-embankment under water surface, such as con- cealment, difficult to be detected and found out, etc. , the technique of multi-beam swath bathymeter is combined with the tech- nique of dual-frequency identification sonar, and then the planned survey lines are correctly arranged to ensure the whole cover- age of the scanning survey made on the underwater exterior disease. Through installing GPS receiver on the transducer of dual-fre- quency identification sonar, the central location of disease is correctly marked on the relevant multi-beam point cloud chart ac- cording to the location information concerned, thus the limitations of both the techniques are fetched up; which is already applied to the engineering practice. The practice shows that the selection of the multi-beam swath bathymeter system with small beam an- gle can obtain the data with high quality and high solution ratio, which is convenient to find out the diseases of micro-exterior breakings, flakes, etc. Furthermore, the speed of the observation bolt is better not to be too fast and must be controlled within a range of 5 knots, while the survey line must be parallely arranged with the direction of water flow, when the detection is made with sonar. On the whole, the exterior diseases of underwater damage, collapse, etc. can be correctly found out by combination of both the techniques. The study result provides a technical support for the disease detection and risk elimination and reinforce- ment of the similar project concerned.