Research On The Hydraulic Cleaning Technology For Large-diameter Sewers

With the constant expansion of economic development and urban, the scale ofurban sewers keeps increasing, and the drainage pipe deposition is getting more andmore serious. Both at home and abroad, many urban sewers appeared different degreeof deposition problem, and the research on large-diameter sewers’ dredging is less. It isstill a lack of affordable dredging and dredging equipment, the dredging work is still aproblem. This article provides a simple and feasible technology, and developed ashipborne hydraulic cleaning system for large-diameter sewers. This cleaning systemprovides a new technology and methods for the increasingly difficult dredging work oflarge-diameter sewers, and it has important practical value and broad applicationprospects.On the basis of the existing sewer dredging technology, and in combination withthe specific characteristics of the large-diameter sewers in mountainous city, such as theintercepting trunk pipe, the technology idea of mechanical agitation+hydraulicdredging is put forward, and the work plan of dredging boat working in pipe andoperated by operators on the ground is presented in this paper. The dredging boat that isworking in pipe is used as dredging work main to achieve the removal of sediments inthe sewers.The laboratory experiment of hydraulic re-suspension of the sediments in pipe with2D-PIV has been carried out. The experiment showed that, mechanical agitation caneffectively stir up the sediments and make them into mixture. And the experimentproved that, the technology idea of mechanical agitation+hydraulic dredging is feasible.Besides, related hydraulics parameters that is used to guide the design and developmentof the cleaning system have been obtained.The whole cleaning system has been developed. Because of the diversity of theposition of sewers and the particularity of working environment within sewers, thecleaning system should be compact, flexible, safe, reliable, easy to remove and handle,easy to operate, and able to adapt to the complex terrain conditions. The cleaningsystem consists of dredging boat, pneumatic rubber weir for water level control, andabove-ground operating system. The dredging boat working in the sewer and operatedwith above-ground operating system by operators on the ground. The pneumatic rubberweir for water level control staying at the site of downstream inspection well, controls the sewage water level in the working pipe to make the dredging boat work at theappropriate water level. After the cleaning system optimized and improved for severaltimes, the third-generation shipborne hydraulic cleaning system that can be able to adaptto the complex terrain conditions has been obtained.The field tests of the third-generation hydraulic cleaning system in the actualsewers have been carried out, and the cleaning performance of the system in the opensewer and the above-ground sewer has been tested. The results showed that, thehydraulic cleaning system for large-diameter sewers used in the dredging work of thelarge-diameter sewers is feasible, and the dredging effect is good, the cleaning system isable to complete the dredging work. The cleaning system is flexible and has a strongadaptability, it is an affordable and environment-friendly dredging technology.