埋地冲洗管线强度计算及影响因素规律分析

研究了冲洗管线在自重、内压、温差和土壤力综合作用下的强度分析方法,给出埋地冲洗管线应力计算公式。采用有限单元法对某冲洗管线重点部位进行力学特性分析,得到其真实应力分布状态,对比了理论计算结果与数值结果误差,证实轴向应力理论计算结果偏保守。对不同壁厚、不同环境温度和不同压力下的管线力学特性进行讨论,结果表明,管道的环向应力起主导作用,且埋深0m~0.75m内管线的环向应力变化明显,因此,当考虑温差及波动内压作用时,该段管线力学特性应引起足够重视;受环境温度影响,管线最大等效应力与总位移规律近似相反,即等效应力最小,总位移近似最大;考虑到等效应力随压力变化规律,不同季节宜采用不同的冲洗压力以满足安全运行要求。

Strength calculation and parametric analysis for influential factors of buried flush pipeline

The strength analysis method of the flush pipeline under the weight,pressure,temperature difference and soil force was studied and the stress calculation formula of buried flush pipeline is provided.The mechanical properties of the key parts of a flush pipeline with the finite element method were analyzed to obtain the realistic stress distribution.Comparisons of the error between analytical results and numerical results show that the analytical results of axial stress are conservative.The analysis pipeline with different wall thickness,different environmental temperatures and different pressure shows that the hoop stress plays a main role,and it changes obviously within the 0 m~0.75 m depth.Therefore,enough attention should be paid to the mechanical properties of this pipeline when considering the temperature difference and fluctuating internal pressure.Affected by the environment temperature,maximum equivalent stress shows an opposite trend to the total displacement,namely,when equivalent stress is minimum,the total displacement is approximately at maximum.Taking into account the equivalent stress variation with pressure,different flushing pressures should be adopted in different seasons to meet the requirements of safe operation.