ВЛИЯНИЕ ВНУТРЕННЕГО РАБОЧЕГО ДАВЛЕНИЯ И ТЕМПЕРАТУРНОГО ПЕРЕПАДА НА МАКСИМАЛЬНО ДОПУСТИМУЮ ВЕЛИЧИНУ ПРОЛЕТА ПРИ ПОДЗЕМНОЙ ПРОКЛАДКЕ ТРУБОПРОВОДА НА ОПОРАХ ИЗ КОНТЕЙНЕРОВ С ГРУНТОМ

Abstract

For fixing the vertical position of pipelines at the design marks during the construction in the subsiding soils with melt island permafrost, the authors of this paper propose a method of laying pipeline on a special pyramid of containers with soil that are installed in the trench in the form of supports with a certain spacing. The spacing is determined by the maximum span length allowable in terms of strength. The maximum allowable length of the span depends on various factors. From the practical point of view, the most interesting is the effect of internal operating pressure and temperature differential. Aims and Objectives Determination to what extent the internal working pressure and temperature differential influence the maximum allowable span of the pipeline laid on the supports of containers filled with soil. Methods Theoretical study of the influence of internal working pressure and temperature differential on the stress-strain state of the pipeline and the maximum span length allowable in terms of strength. The calculations are based on the improved calculation of beam crossings without compensation for longitudinal stresses. Results The impact of internal operating pressure and temperature differential on the maximum allowable span length and stress-strain state of a pipe section has been studied. The plots of changes in the allowable span length and longitudinal stresses, depending on the internal operating pressure and temperature differential were constructed. Conclusion Results of calculations established that the increase in the value of the temperature differential led to increased longitudinal stresses in the pipeline and, consequently, to decreased maximum allowable length of the span. Moreover, the gradient of changes in the longitudinal stresses generated both at positive and at negative differentials is approximately equal in magnitude throughout the range of considered values of the temperature differential. When the temperature differential increases, the maximum allowable span length decreases linearly to the value of the temperature differential, at which the governing stresses are changed in choosing the maximum allowable span length.