What are the requirements for plastic pipes for underground water supply and drainage in engineering design?
The design unit is very important to the requirements of plastic pipe, because the ultimate purpose of plastic pipe production is to meet the needs of users, design units in a sense is the user, so pay attention to the design unit of plastic pipe products related requirements, for the production enterprises have a certain guiding significance. As a design unit, in addition to the basic requirements for the use of plastic pipe products, the following seven requirements for plastic pipe products will be considered:
First, to meet the national standards, industry standards and technical specifications, group standards and other related product standards. Products, for there is no standard in accordance with the "new technology of the ministry of construction application management rules" (jianke [2002] 222) the provisions of article 20: the country's current engineering construction standards, rules and regulations not covered the promotion project, the ministry of construction according to the mandatory project construction and related standards, specifications and code requirements, specify the detection institutions designated by the state test, issue the test report, entrust the relevant units to compile unified promotion project technical guidance of scientific and technological achievements by the ministry of construction, and the technical expert committee authorized by national ministry of construction issued after use. The technical guidelines may be used as the assessment standards for agreed quality indicators when signing contracts, and as the technical basis for the compilation of survey and design documents, construction drawing review, construction installation, project supervision, quality inspection, assessment and acceptance, and use and maintenance management.
Second, the use of recycling materials and calcium carbonate should be strictly required. According to the current market situation, the design unit should refuse to use the products with external recycled materials. For the use of the factory's recycled materials, must be from the same product production; Clean and free of impurities and other resins; There is no obvious difference between its performance and qualified new material. The added percentage shall not exceed the product standard. If there is no standard, use it sparingly or not at all. PE and PP wall tubes should not use calcium carbonate.
Thirdly, in terms of strength, the product should meet the specific requirements of the design institute for anti-pulling, bending and compressive resistance.
Fourth, the elastic modulus of the product, the product to meet a certain stretch, bending, compression requirements. It is suggested that the plastic pipe manufacturer should do some basic research work, which is very helpful for their products to adapt to the market.
Fifth, the long-term performance of plastic pipe must meet certain requirements. The structural design should be based on the minimum physical performance over a period of 50 years, known as "long-term performance". Foreign data show that the long-term elastic modulus is only 20%-50% of the short-term elastic modulus, which has a great influence on the calculated deformation.
Sixth, about the ring stiffness of the product. Enterprises are not encouraged to excessively pursue ultra-high ring stiffness. When metal and plastic composite means are used to increase the ring stiffness, it should not be emphasized that the two materials should "learn from each other to make up for each other's shortcomings" in terms of performance, but should also fully study the adverse factors of interaction between the two materials and take reliable measures to eliminate the adverse factors in product structure and molding process.
Seventh, in terms of pipe connection, the requirements of the design institute for pipe interface are mainly reflected in two aspects: sealing performance and convenient construction. According to the current product status, enterprises should give priority to choosing the appropriate connection mode and strengthen the research and standardization of rubber ring socket connection technology for large-caliber drainage pipes.
