串联式能量排桩逆转流向现场热响应试验

Field Thermal Response Test of Reversed Flow Direction of Series Energy Row Piles

能量排桩在温度作用下会引起桩体热应力.针对黏土地基中串联式摩擦型能量排桩循环水流向开展现场热响应试验研究,实测进/出口水温、桩身温度以及桩身热应变等变化规律;分析能量桩换热、桩体轴向约束应力等热力响应特性.研究结果表明,本文试验条件下,在3.0 kW恒定输热功率下,循环水流向逆转前后,串联能量排桩的换热平衡能迅速达到稳定状态;串联能量排桩循环水流向逆转对于正中桩基本无影响,而对两边桩有较大影响,流向逆转不会降低排桩整体换热效果,且在流向逆转后,桩体最大轴向约束应力为-2.09 MPa,在桩体承载范围内,不影响桩体承载性能.

The thermal stress of pile body will be caused when the energy row pile is under the action of temperature.In this paper,the field thermal response test was carried out to study the circulating water flow direction of the series friction type energy row piles in clay foundation.The variation laws of the water temperature at the inlet/outlet,the temperature of the pile body,and the thermal strain of the pile body were measured.The thermal response characteristics of the energy pile heat exchange and the axial restraint stress of the pile body were analyzed.The results showed that under the condition of constant heat transfer power of 3.0 kW,before and after the reversal of circulating water flow direction,the heat exchange balance of series energy row piles could reach a stable state rapidly.The reversal of circulating water flow direction of series energy row piles had little effect on the center pile,but had a greater impact on both sides of the pile.The reversal of flow direction would not reduce the overall heat exchange effect of the row piles,and after the flow direction was reversed,the maximum axial constraint stress of the pile body was-2.09 MPa,which did not affect the bearing performance of the pile body within the bearing range of the pile body.