Wuhan sponge city construction, carat tube construction application points

Core Requirements for Drainage Pipelines in Wuhan Sponge City Construction

Wuhan is located in the middle and lower reaches of the Yangtze River. The subtropical monsoon climate leads to concentrated and short-term rainfall in summer. Leakage and insufficient drainage capacity of the old pipe network are the core incentives for frequent flooding in the past. The construction of sponge city revolves around the six-character policy of "seepage, stagnation, storage, purification, use, and drainage", which requires that the drainage pipes have the characteristics of anti-settlement, corrosion resistance, and large flux, and are suitable for the geological conditions of Wuhan's soft soil and high groundwater level, so as to meet the stability requirements of long-term use.

Performance Advantages of Carat Tube Adapted to Sponge City Scenario

The carat tube is a high-density polyethylene structural wall hot winding pipe, with its own ring stiffness covering a wide range, which can adapt to the needs of different buried sections. The polyethylene material is resistant to acid and alkali corrosion, and is suitable for the complex water quality of the Wuhan rain and sewage confluence section. The thermal winding formed structural wall has strong impact resistance and is not easy to be broken due to ground subsidence. The interface is connected by hot melt sockets, which has excellent sealing performance and can effectively avoid groundwater pollution caused by pipeline network leakage.

Key points of selection and preparation before construction of carat tube

Before construction, it is necessary to combine the runoff calculation results of the project section to select carat pipe products with corresponding diameter and ring stiffness. When entering the site, it is necessary to focus on sampling the wall thickness, ring stiffness and interface flatness of the pipe. Unqualified products are not allowed to enter the site. After the trench is excavated, the bottom of the groove needs to be leveled, and the soft foundation section needs to be laid with a 15 to 20 cm thick gravel cushion and compacted to avoid uneven settlement of the extruded pipeline in the later stage.

Key Control Points of Carat Tube Site Construction

When the pipeline connection adopts the hot-melt process, it is necessary to strictly control the heating temperature and duration to avoid the problem of virtual welding and over-welding of the interface. During the construction in the rainy season, temporary drainage ditches and water collection wells need to be set at the bottom of the trench to avoid water accumulation in the trench and cause the pipeline to float. When backfilling, it is necessary to fill the pipe with fine sand to 30 cm above the top of the pipe, and then use plain soil to layer and compact. It is strictly forbidden to directly backfill the large masonry extrusion pipeline. After the construction is completed, a water closure test should be done according to the specifications to confirm that there is no leakage before the upper pavement construction can be carried out

At present, carat tubes have been applied in rain and sewage diversion and road runoff control projects in many sponge cities in Wuhan. Standardized construction control can further amplify product performance advantages, effectively reduce urban waterlogging risks, and improve the construction effectiveness of sponge cities.