冷-热不平衡热荷载下黏土地基中能量桩长期热-力学特性  

Long-term Thermo-mechanical Behavior of Energy Pile in Clay under Unbalanced Cooling-heating Cycles

作　　者：杨涛[1] 瞿广鑫 花永盛 YANG Tao;QU Guangxin;HUA Yongsheng(Department of Civil Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Guizhou Architectural Design&Research Institute Co.,Ltd.,Guiyang 550081,China;Yancheng Dongting Investment Co.,Ltd.,Yancheng 224001,China)

机构地区：[1]上海理工大学土木工程系,上海200093 [2]贵州省建筑设计研究院有限公司,贵州贵阳550081 [3]盐城市东亭投资有限公司,江苏盐城224001

出　　处：《防灾减灾工程学报》2022年第6期1333-1340,共8页Journal of Disaster Prevention and Mitigation Engineering

基　　金：上海理工大学沪江基金项目(D14003)资助。

摘　　要：建立了热-渗流-力(T-H-M)三场耦合能量桩有限元数值分析模型,研究了力学荷载组合不同热聚集度(桩的放热量与吸热量之比)温度荷载下黏土地基中能量桩的长期热-力学特性,包括桩身温度、桩头沉降、桩身轴向应力、地基土温度和超孔隙水压力特性等。计算结果表明:冷-热平衡时桩头沉降随温度荷载循环的增加逐渐增大,桩头发生沉降累积,桩身轴向应力和地基土温度变化的幅值不随温度荷载循环而变化。当桩的放热量大于吸热量时,桩身温度随温度荷载循环的增加而升高,桩头沉降随之减小,但热荷载循环对桩身轴向应力没有影响。桩周土温度随热循环的增加而逐渐增大,产生热聚集现象。温度荷载的热聚集度数值越大,桩身和桩周土的温度越高,桩身最小压应力越大,桩头沉降越小。温度荷载引起的超静孔隙水压力数值很小。A coupled thermal-hydro-mechanical(T-H-M)finite element model is established to investigate the long-term thermal-mechanical behavior of a single energy pile in clay subjected to mechanical load and thermal load with different thermal aggregation degrees(defined as the ratio of the heat injected into the ground to that extracted from the ground),including the pile temperature,pile head settlement,pile axial stress,ground temperature and the excess pore water pressure in the soil around the energy pile.The simulation results show that when the heating and cooling loads are reasonably balanced,the pile head settlement increases with the number of thermal cycles,that is,the pile head settlement accumulates gradually,while the amplitudes of the axial stress in the pile and the soil temperature around the pile keep the same.When the heating load is dominant,the pile temperature rises with the increase of thermal cycles,and the pile head settlement decreases.Thermal cycles have no effect on the axial stress in piles.With the increase of the thermal cycles,the temperature of the surrounding soil gradually increases,resulting in heat accumulation in the ground.The more dominant the heating load is,the higher the temperatures of the energy pile and the soil around the pile,the larger the minimum compressive stress in the energy pile,and the smaller the pile head settlement.The thermally induced excess pore water pressure within the surrounding soil is very small.

关 键 词：能量桩 长期热-力学特性 不平衡冷-热循环 黏土地基 有限元法 

分 类 号：TU443[建筑科学—岩土工程]