不同压实度下能量桩的热力学效应

Thermal-mechanical characteristics of energy pile under different degree of compaction

能量桩是1种新型桩基埋管地源热泵技术,在传递上部荷载的同时获取地热能源;但是目前对于桩土之间的相互作用以及桩体的热力学效应却研究较少。基于模型试验方法,采用打夯法和砂雨法,对饱和砂土中不同压实度下的桩体热力学效应和承载特性进行对比研究。试验测得桩体和桩周土体温度变化、桩周土体水平压力变化、桩体应变应力以及桩顶位移。结果表明,加热时,桩周土体会有水平土压力的增大,桩体内部会有压应力的产生,桩顶会产生向上的位移,并且压实度越大,桩周水平土压力越大,桩体应力越大,桩顶位移变化越小。

Energy pile is an emerging technology incorporating heat-exchange elements. It provides necessary support for buildings and acts as heat exchanger units to obtain geothermal energy. However, the research focused on the thermal-mechanical behavior between the pile and soil is limited. Based on the model test, the thermal-mechanical behavior and bearing character were studied through tamping and pluvial deposition methods on saturated sand. The temperature of the pile and surrounding soiU horizontal soil pressure, thermal strain, thermal stress,and the pile head settlement were monitored. The results indicated that horizontal soil pressure increased when the pile was heated. The thermal stress and pile heave were also produced. In addition,the larger the compaction degree, the larger was the horizontal soil pressure and the thermal stress with heating. However,the pile heave would be smaller as the degree of compaction was increased.