Stress Analysis In The Practical Engineering Of Big Diameter Directly Buried Heating Pipeline

Because the directly buried technology has its unique advantages, Such as low energyconsumption, simple construction, saving investment, not damage to the environment, etc. Sothe directly buried technology is developing rapidly in our country. In1998, our countrypromulgated《the town of directly buried heating pipeline engineering technical regulations》(CJJ-T81-98). In recent years, due to the rapid growth of central heat supply system, heatingpipe to the development of large diameter and pipe diameter has exceeded DN1000mm inmany heating engineering. However, the domestic current《technical regulations》limitsdiameter equal to or less than DN500, therefore discipline cannot meet the requirements of thedesign of big diameter, and the stress of large diameter related research. So this topic isproposed against big loading characteristics of directly buried heating pipe and the stresscheck condition is studied, to guide the correct design and installation of heating pipe. In thedesign, on the basis of fully considering the security, as far as possible, we should make fulluse of the strength of the pipeline itself characteristics to reduce construction cost.In this paper, the basic theory of the directly buried heating pipe are analyzed, andpointed out that in the influence factors of small diameter pipe stress analysis to ignore, thereare many influence factors in large diameter pipe stress analysis has become a can’t ignore theinfluence of factors, such as the weight of the piping and medium influence on the friction andso on, and put forward the calculation formula of correction.Given a lot of big diameter of the actual engineering design, caused by a lack of stresscalculation and analysis, and affect the number of fixed block, compensator, increase theinvestment of the project. On a practical engineering design in this paper has carried on thecomprehensive stress analysis and calculation, in satisfies the requirement of stress on thebasis of reasonable arrangement of pipeline accessories, greatly reduce the number of fixedblock, compensator, and the tee by ANSYS finite element analysis software, support theoptimization scheme of tee.The main research results of this paper are to put the pipe weight and medium weightconsidering the friction in the formula, and using the formula of actual engineeringcalculation; Calculation of transition section length, consider the internal pressure stress effectand the action of internal pressure imbalance; When calculating fixed pier thrust andconsidering the different for the return pipe stress; In the ring to the stress calculation, the use of the wall thickness of the wall thickness is the most adverse conditions, give fullconsideration to the actual operation situation, etching, welding defects and other factors.This study found that in fill directly buried heating pipe in practical engineering, thereare many parts can be optimized. If it can be noticed in the design and attention to these parts,then buried or big diameter thermal pipeline engineering cost would be significantly reduced;Secondly, with the development of computer simulation technology, it is necessary in thedesign of the finite element analysis was carried out on the easy damage part, to guide thedesign.