能源桩-土体接触力学特征试验装置的研发与应用

Development and Application of Apparatus for Contact Mechanics of Energy Pile-soil Interface

研发了能源桩-土界面特性测试仪,在测试仪中安装可控温钢筋混凝土模型桩,在桩周围填充各类土体,模拟不同地基中的能源桩。通过对土体施加一定的恒定竖向荷载模拟不同深度的土层。模型桩中安装有换热管,利用低温恒温水浴,通过循环液控制桩体的温度,模拟能源桩吸热、放热过程。利用铂电阻温度传感器测量桩和土体的温度;利用安装在桩体表面上的微型土压力计测量桩-土界面的法向应力;利用FBG准分布式光纤传感技术测量桩体的周向变形。以砂土地基为例,通过冷热循环试验,准确得到了桩温、土温、桩-土界面的法向应力和桩的周向变形,说明EPSICA可以用于揭示桩-土界面的接触力学特征,为能源桩的热、力学行为研究提供了新的手段。

An energy pile-soil interface characteristic apparatus(EPSICA)was developed.Energy pile model was installed in the middle of the apparatus.Different soil can be filled around the energy pile model to simulate pile in different foundations.The soil layers at different depths were simulated by applying corresponding loads on the filled soil.The temperature of energy piles was controlled by water bath cycling.The Pt100 sensors were installed in the pile and soil to measure the temperature changes.A miniature earth pressure cell was installed on the pile surface to measure the normal stress on the pile-soil interface.The FBG quasi-distributed optical fiber technology was used to measure the circumferential deformation of the pile.Taking the sand foundation as an example,the contact mechanical characteristics of pile-soil interface during the heating and cooling cycle was studied based on the temperature of pile and soil,normal stress on pile-soil interface and circumferential deformation of pile.The developed apparatus provides a new method for the study of thermo-mechanical behavior of energy pile.