红粘土传热特性及其渗流-传热耦合作用机制研究

项目名称： 红粘土传热特性及其渗流-传热耦合作用机制研究

项目编号： No.41502284

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 地质学

项目作者： 曾召田

作者单位： 桂林理工大学

项目金额： 20万元

中文摘要： 红粘土是我国西南地区广泛分布的一类特殊土，因其特殊的矿物组成和“二级”微孔隙结构，红粘土具有复杂的传热特性及渗流-传热耦合作用机制。目前国内外对此缺乏系统的认识，阻碍了该地区地热资源的有效利用及相关工程灾害的防治。本项目从孔隙水与土颗粒的结合形态及相互作用机理入手，研究红粘土热特性参数随含水量的变化规律，结合复合介质理论确定水-土相互作用下热导率计算模型；利用核磁共振、压汞试验等技术手段，获取红粘土内部的微孔隙结构分布特征及确定孔隙水与土颗粒的结合形态，探讨红粘土传热过程中土-水结合形态及其微观分布的演化规律，建立红粘土微结构特征量和含水量与热特性参数的定量关系；基于小模型实验，研究在渗流和含水量变化条件下红粘土的传热机制；建立红粘土渗流-热传导耦合的理论模型，并对其进行试验验证。本研究不仅为红粘土地区地热能的合理利用提供可靠的理论模型与分析方法，同时为解决有关红粘土灾害问题提供理论依据。

中文关键词： 红粘土；传热特性；渗流-传热耦合作用机制；土中结合水；微观结构

英文摘要： Red clay is a kind of special soil, which extensively distributed in the southwest region of China. As its unique mineral compositions and micro-pore structures, red clay has a complex heat transfer characteristics and flow-heat coupling mechanism which have not been systematically investigated in home and abroad at present. Therefore, it has hindered the effective utilization of geothermal energy and disaster prevention of related engineering. The project starts from binding forms of pore water and soil particles and its interaction mechanism to study the relationship of the thermal parameters and water content in red clay. Combined with composite medium theory, the calculation models of thermal conductivity with water-soil interaction mechanism have been determined. With the modern testing techniques such as mercury intrusion porosimetry(MIP) and nuclear magnetic resonance(NMR), the microscopic pore structure characteristics and the binding forms of pore water and soil particles can be obtained to investigate the evolution laws of soil-water binding forms and its microscopic distribution during the heat transfer process of red clay and establish the quantitative relationships of the micro-structure characteristics quantities and water content, thermal parameters. Based on small-size model test, the heat transfer mechanism of red clay with the conditions such as flow and water content changing is analyzed to establish the flow-heat coupling theoretical model of red clay and make test verifications. The research not only provides reliable theoretical models and analysis methods for exploiting geothermal energy in red clay region, but also plays an important theoretical guiding role in solving engineering disasters related to red clay.

英文关键词： red clay;heat-transfer characteristics;flow-heat coupling mechanism;soil bound water;microstructure