考虑热水力耦合的管-土作用机理研究

Under the actions of temperature and pressure of heat medium, pressure of superstratum, groundwater, and so on, mechanics properties, interaction mechanism, design optimization is the key to ensure the security and durability of the pipeline in service. Therefore, thermal hydraulic and mechanical coupling mechanism of pipe-soil is studied by using the method of model test, theoretical calculation and numerical simulation. Firstly, temperature control triaxial test is carried out on the silt and clay under no drainage considering the effect of temperature of heat medium in the pipeline, and the effect of temperature on the property of soil and analyzed quantitatively. Secondly, the model test and theoretical calculation are developed under the conditions of different temperature and pressure of the heat medium, thickness of the superstratum, and so on. Then, the distribution of temperature, stress and displacement is obtained and the interaction mechanism of pipe soil is revealed under the condition of thermal hydraulic and mechanical coupling; Finally, the three-dimensional numerical calculation model of pipe soil considering thermal hydraulic and mechanical coupling is established, and the effects of pipe diameter, pipe soil relative stiffness, buried depth, uneven settlement and other factors impact on soil thermo-dynamics characteristics are discussed, and are compared with the results of model test. The results provide a scientific basis for the optimum design, the safety assessment and control of pipeline, on the other hand，it promotes inter- disciplinary and application in the urban underground pipeline.

在热媒温度压力、上覆土压力、地下水等作用下，管-土力学特性、管-土作用机理、设计优化是确保管线服役安全、耐久的关键科学问题。为此，本项目采用模型试验、理论计算和数值模拟等方法开展管-土热水力耦合作用机理研究，首先考虑热媒温度作用，开展不排水条件下粉、黏土温控三轴试验，定量地分析温度对土性的影响；其次，通过开展不同热媒温度和压力及上覆土层厚度等工况下的模型试验和理论计算，获得管土温度、应力、位移等的分布规律，揭示热水力耦合条件下管土作用机理；最后，建立管-土热水力耦合三维数值计算模型，探讨管径、管土相对刚度、埋深、不均匀沉降等因素对管土热力学特性的影响，与模型试验进行对比验证。研究成果一方面为热力管线的优化设计、安全评价和控制提供科学依据，同时促进了学科交叉及城市地下管线中的应用。

在热媒温度压力、上覆土压力、地下水等作用下，管-土力学特性、管-土作用机理、设计优化是确保管线服役安全、耐久的关键科学问题。为此，本项目采用模型试验、理论计算和数 值模拟等方法开展管-土热水力耦合作用机理研究，首先考虑热媒温度作用，开展不排水条件黏性土温控三轴试验，分析温度对土性的影响；其次，通过开展不同热媒温度和压力及上覆土层厚度等工况下，黏土、砂土中管线在高温、低温和冲击荷载作用下的模型试验和理论计算，获得管土温度、应力、位移等的分布规律 ，揭示热水力耦合条件下管土作用机理；最后，建立管-土热水力耦合三维数值计算模型，探讨高温、低温和冲击荷载作用下管径、管土相对刚度、埋深、不均匀沉降等因素对管土热力学特性的影响，与模型试验进行对比验证，提出了冲击荷载作用下管线的优化设计计算方法。研究成果一方面为热力管线的优化设计、安全评价和控制提供科学依据，同时促进 了学科交叉及城市地下管线中的应用。