用于疏浚工程泥浆密度测量的电阻层析成像技术

In the lakes, rivers, harbors and other water bodies, dredging usually plays an indispensable role in guaranteeing the shipping safety, promoting ecological restoration, maintaining/improving the environment of remote islands and reefs. On the cutter suction dredgers and trailing suction hoppers, the γ-ray densitometers and electromagnetic flow meters have been widely employed for measuring the online slurry density and productivity. These parameters have usually been considered as the most important inputs to the automatic dredging systems. In consideration of the potential risks of the γ-ray densitometer, i.e., on the health of crew, public safety and environment, an orderly withdrawal mechanism of radioactive sources has been established in many countries and regions. The electrical resistance tomography(ERT)technique utilizes the electrode arrays on the periphery of pipe/vessel to investigate the internal on-going flows, which can reflect the slurry density and distribution. It has the advantages of no radiation, full field measurement and real-time visualization. The ERT measuring system has been carefully re-designed to fit both the in-land and sea water. Preliminary tests show that the developed ERT data are in good consistency with the γ-ray densitometer, demonstrating its feasibility as an online slurry densitometer. Furthermore, ERT can provide the real-time visualization, which is of great significance for monitoring the dredging pipe and reducing the probability of pipe blockages.