温度影响下供水管道力学行为数值模拟研究

Numerical Simulation Investigation of Mechanical Behaviors of Water Mains under Temperature Effect

夏冬季节供水管道漏损和爆管事故频发,表明温度是影响供水管道结构运行安全的重要因素。然而,已有研究大多忽视温度变化对供水管道力学行为的影响。因此,本文采用有限元数值模拟方法,建立了考虑管‑土相互作用的热力耦合三维数值模型,研究了地表温度变化对供水管道周围土壤温度场的影响,分析了供水管道因土壤与水温差异造成的力学行为变化,研究了不同温度影响下埋深、管径和壁厚三个因素对供水管道力学行为的影响。最后,采用均匀试验设计方法,通过大量的有限元数值模拟,建立了供水管道最大应力、最大竖向位移和地表温度变化之间的经验预测方程。研究结果表明:土壤的温度变化幅度小于地表的温度变化幅度,即存在“冬暖夏凉”的效果。因土壤与水体的温度差异,供水管道容易出现“热胀冷缩”的现象,使得供水管道发生漏损或爆管。本文建立的经验预测方程和有限元模拟结果拟合较好,可直接用于评估供水管道不同季节的结构运行风险和沉降风险。

Water mains are frequently damaged with leaking and bursting accidents in both summer and winter seasons,highlighting the significant influence of temperature on the structural operational safety of water mains.However,existing studies have often ignored the effect of temperature variation on the mechanical behaviors of water mains.In this study,the finite element numerical simulation method was employed to build a thermal mechanical coupling three-dimensional numerical model,considering the pipeline-soil interaction effect.We investigated the effect of ground temperature variation on the thermal field of the soils surrounding the pipeline,studied the variation of the mechanical behaviors of water mains induced by the discrepancy of soil and water temperature,and analyzed the influence of buried depth,pipe diameter,and wall thickness on the mechanical behavior of water mains under different ground temperatures.To establish empirical prediction equations between maximum stress and maximum vertical displacement of water mains and ground temperature,the uniform test design method was applied and numerous finite element numerical simulations were carried out.The conclusion indicates that the temperature variation amplitude of the soil is smaller than that of the ground surface,resulting in an effect called‘warm in winter and cool in summer’.Due to the discrepancy between soil and water,water mains are prone to a phenomenon called thermal expansion and cold contraction,leading to the occurrence of leaking and busting of water mains.The established empirical prediction equations agree well with the finite element simulation results.They can be used to evaluate the structural operation and settlement risk of water mains in different seasons directly.