Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Research on Pneumatic Pump Micro-Turbulent & High-Precision Dredging Construction Process Basedon Urban Inner Lake
Kaifei Cao1, Chaozhe Yuan2*, Xunping Lin1, Xuyuan Qiu1, Jiacheng Luo2, Jiachen Zeng2, Sheng Wang2, Wenbo Sun2*
Chaozhe Yuan
CCCC SDC (Fujian) Communication Construction Engineering Co., LtdXiamen, Fujian, China
National Engineering Research Center of Dredging Technology and Equipment
Shanghai, China.

ABSTRACT

Pneumatic pump is an environmentally friendly dredging equipmentthat uses negative pressure to suck in bottom sludge and transports it by
air as power.At present, this equipment has not been widely used inurban lake dredging projects, and the construction technology ofpneumatic pump ships has not been formed.The disturbance range anddredging accuracy of different construction process parameters andpump head structure are compared and analyzed, based on the aerial
photography of the pneumatic pump construction process, the microdisturbance monitoring of water sampling and the measured data of theterrain elevation after dredging,in the contaminated sediment dredging
project of Yundang Lake in Xiamen City, Fujian Province, China.

In order to solve the problem of poor environmental protection in theprocess of traditional dredging , the pneumatic pump has been
introduced into the city’s inner lake dredging projects. Based on fieldprocess optimization, dredging accuracy and diffusion range
monitoring analysis, the following conclusions are given: the formed
pneumatic pump dredging process has the advantages of microturbulent & high-precision; the lake bottom elevation accuracy of thedredging process is controlled within 0.05m, and the increase ofsuspended matter 10m away from the boat is less than 10 mg/L.

Based on this, the diffusion characteristics of the equipment's dredging
process and the range of dredging accuracy are given, and a pneumatic
pump micro-turbulent & high-precision dredging construction process
is formed.The research results can not only ensure the environmental
protection of the urban lake dredging process, reduce secondary
pollution to the water body, but also ensure high-precision dredging,and improve the quality and efficiency of dredging. And it is of greatsignificance to the improvement of the urban environment.

KEY WORDS:

Pneumatic pump; Urban inner lake; Processoptimization; Environmental dredging; Micro-turbulent; High-precision

INTRODUCTION
The city’s inner lake has poor fluidity ， and affected by the influx ofdomestic sewage, which lead to serious pollution (Zheng, 2020).
Traditional dredging equipment such as grabs, water excavators, andsmall cutter suction boats have poor environmental protection duringdredging.The main problems are poor dredging accuracy, large water
disturbances, and inevitable secondary pollution (Liu, 2020, Wang,2016, Yuan, 2020, Liu, 2018).

PROJECT OVERVIEW
Yundang Lake is located in the center of Xiamen City. The source of its
sediment is mainly suspended solids in the West Sea water and sewage
from the flood drainage ditch. It causes serious pollution to the bottom
soil of Yundang Lake and poses a long-term threat to the water
environment and ecosystem. In addition, when the dissolved oxygen in
the water is insufficient, the bottom mud undergoes anaerobic
fermentation and produces foul odor.

At present, in the field of dredging, only the standard of ‘Design codefor dredging and reclamation works’ (Ministry of Transport of thePeople's Republic of China, 2012) has stipulated the increase ofsuspended sediment caused by the dredging process when it is adjacent
to aquaculture areas, and it is required that the increase should not begreater than 10mg/L. Environmental protection dredging technology
currently mainly includes Pneumatic pump, small cutter suction vessels
with environmental protection covers, anti-fouling curtains arranged in
dredging waters, and flocculant spraying during the dredging process(Wei, 2019, Wei, 2021).

Based on Xiamen's strategic goal of building an internationallyrenowned garden city and a model city of beautiful China, extremely
high requirements are put forward for the dredging project of Yundang
Lake. At present, there are mainly the following two technicaldifficulties that need to be overcome urgently.

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