HDPE Double Wall Corrugated Pipe for Rain and Waste Infrastructure

Performance and application of HDPE double wall corrugated pipe

In the past, the pipes used in domestic underground water supply and drainage pipeline systems were mainly concrete pipes, reinforced concrete pipes, and cast iron pipes. Due to the long construction period and large traffic volume, the underground concrete drainage pipes and cast iron water supply pipes in some road sections have been damaged and aged one after another, resulting in Blockage of urban drainage and bursting of water supply pipes not only bring inconvenience to the lives of citizens, but also due to the complex construction process, the large number of pipe joints, and the difficulty in timely treatment of anti-leakage, the accumulation of time will cause road foundations to sink, and sewage seepage will also pollute Soil and water sources have become public hazards. For this reason, the use of hdpe drainage pipe with good pressure resistance, light weight, corrosion resistance and environmental protection has become a top priority.

HDPE Double Wall Corrugated Pipe Factory

1. Performance characteristics of HDPE double wall corrugated pipe

HDPE double wall corrugated pipe has a smooth inner wall and a series of hollow corrugations perpendicular to the axis on the outer wall. It has a unique structure and has superior mechanical, physical and chemical properties. It has a wide range of applications and has high economic value. Because of its superior product performance, it has been widely used in municipal sewage projects, farmland irrigation projects, water delivery projects, telecommunications projects and other fields, and has been listed as a key promotion project of scientific and technological achievements by the Ministry of Construction. In practical application, HDPE double wall corrugated pipe also has performance characteristics that other pipes do not have, such as light weight, toughness, pressure resistance, impact resistance, acid and alkali resistance, not easy to break, excellent water absorption, convenient handling, easy construction, and shortened construction period. :

a) The pipe weight is only 0.94-0.96 g/cm3, which is the lightest material among all buried pipes. b) The outer wall of the tube is a hollow rectangular structure with excellent compression resistance. c) The smooth inner wall of the hdpe drainage pipe (the roughness coefficient is only 0.009; the concrete pipe is 0.013) can make the water flow more smooth, and can avoid the accumulation and stagnation of waste, and avoid the advantages of dredging the hdpe drainage pipe. d) The inner wall of the pipe is smooth. Under the same slope laying conditions, the two values of flow and velocity are higher than those of concrete pipes, so the selection of pipe specifications can be smaller than that of concrete pipes. e) It has excellent toughness and plasticity, which cannot be compared with hard concrete pipes and flexible PVC pipes. f) Good water tightness, using rubber sealing ring socket or Huff external solid method to connect the hdpe drainage pipe, which can ensure that the sewage in the pipe does not leak out, and can comply with the uneven settlement of the foundation, and will not cause the disconnection and fracture of the concrete pipe. g) The pipe is made of inert high-density polyethylene, which can effectively resist the corrosion of industrial and domestic sewage.

2. Comparison with traditional pipes

HDPE double wall corrugated pipe is light and tough. Compared with other similar products (cast iron pipe, concrete pipe, ceramic pipe), it is light in handling, labor-saving in operation, and fast in connection. It is a high-efficiency hdpe drainage pipe product. Due to the narrow living space and dense crowds in the city, traditional pipes are often too bulky and inconvenient for construction, resulting in slow construction progress and frequent accidents. The use of HDPE double wall corrugated pipe can change the disadvantages of traditional pipes and improve construction efficiency and economic benefits.

2.1 Comparison of construction procedures

1) Concrete pipe construction process:

Excavation of trenches, installation of templates, sand and gravel cushion, pouring of foundations, foundation maintenance, installation of pipes, construction of pipe seat concrete, interface wiping, masonry inspection wells, water closure test, backfilling

2) Construction flow of HDPE double wall corrugated pipe:

Excavation of trenches, installation of corrugated polyethylene pipe, interface treatment, masonry inspection well, closed water test, and backfilling. From the comparison of the above process flow, it can be seen that the HDPE double wall corrugated pipe reduces the pouring of foundation and pipe seat concrete and the health-preserving environment. Digging trenches, installing pipes, and backfilling can be done in one go, and the process flow of concrete pipes is complicated. For the same section of pipeline, HDPE double wall corrugated pipe can greatly shorten the construction period and save certain engineering costs.

Double wall corrugated pipes are used in municipal drainage projects

① Good sealing performance, strong resistance to uneven settlement The HDPE double wall corrugated pipe is a flexible corrugated polyethylene pipe, and the interface adopts elastic rubber ring socket connection (see Figure 1). The joint sealing performance is good, it can adapt to large-angle displacement and has strong resistance to uneven settlement . ②The inner wall is smooth and the flow rate is large. The inner wall roughness coefficient of the double wall corrugated pipe is n=0.010, while that of the cement pipe is n=0.014. It can be seen that under the same hydraulic gradient condition, the flow rate of the double wall corrugated pipe is 1.4 times that of reinforced concrete pipes with the same inner diameter. Under the same design flow rate and fullness, the slope of the double wall corrugated pipe is only 1/1.96 of the reinforced concrete pipe, which can not only reduce the buried depth of the downstream drainage corrugated polyethylene pipe, reduce the overall cost of the project and shorten the construction period, but also can Appropriately reduce the number of sewage lifting pumping stations, save a lot of operation and management costs and reduce sewage treatment costs.

③Light weight and fast construction. The density of the double wall corrugated pipe is ≤1.5∥cnl3, and its construction does not require large-scale

Lifting equipment, thus reducing the labor intensity of installers; the standard length of double wall corrugated pipe is 6 m/section (and reinforced concrete pipe is generally 2nI/section), so the number of joints is small, and the pipe is connected with a manual hoist to pull the pipe. The depth of 13 rubber rings is enough. Generally, 3-4 people only need 5-8 rain to complete the joint installation of a section of DN500 pipe, which can save more than 50% of the time compared with the installation of cement pipes of the same diameter. ④The project cost is low. Because the pipe does not require concrete foundation and the installation process is simple, the total engineering cost of the double wall corrugated pipe below DN300 is lower than that of reinforced concrete pipes. The difficulty is high, so the cost is relatively high.

HDPE Double Wall Corrugated Pipe for Rain and Waste Infrastructure

Precautions in the construction of double wall bellows

Float pipe problem

The density of the pipeline in the double-walled hollow structure is equivalent to that of water, and it is very easy for the pipeline to float when the trench is filled with water. Therefore, during the rainy season or construction below the groundwater level, the drainage of the trench should be done well; when the old pipes are renovated, the upstream drainage pipes should be blocked and the sewage in the pipes should be discharged to prevent the downstream construction pipes from being flooded. . After the pipeline installation is accepted and accepted, it should be backfilled immediately to a height of 1 times the pipe diameter above the top of the pipe. When the pipeline has not been backfilled and suffers from blisters, re-measurement and visual inspection of the centerline of the pipeline and the elevation of the pipeline bottom should be carried out, and rework should be done if there is displacement, floating, or pulling.

Circumferential bending stiffness of pipes. The size of the drainage pipe is usually controlled by the external pressure load, so the ring stiffness is generally specified for the buried drainage pipe. The sand box test results of Tianjin Municipal Engineering Research Institute show that the overall performance of the drainage pipe under the roadway is the most suitable when the ring stiffness is 8 kN/㎡. For residential areas, the network surface load is small and the top of the pipe is shallow. Optional ring

Tubes with stiffness <8 kN/㎡.

The detection problem of pipeline deformation. At present, the allowable diameter deformation rate of double-wall bellows is generally

Control within 5%. When people can enter the pipe, they can directly enter the pipe to detect the actual deformation value, otherwise, the Roundness plate dragging method can be used for detection.

Some related issues of pipe price and quality. There are many manufacturers of double wall corrugated pipes, but the production quality varies greatly, the price varies greatly, and the market is not standardized. In order to control the price of pipes, the owner's bidding system should be adopted to prevent the construction unit from choosing low-priced inferior products; in order to strictly control the quality of pipes, a quasi-person system should be adopted, and a lifetime responsibility system should be implemented in accordance with international practice.