温度驱动下X形能量桩单桩承载力演化机理研究

Research on the Evolution Mechanism of the Single-Pile Bearing Capacity of X-shaped Energy Piles Under Temperature Effect

摘要:

为揭示温度场、桩形及土的围压对能量桩承载性能的作用机理,开展了温度-桩形-围压多因素耦合作用下能量桩的承载力演化试验。结果表明:(1)随着温度升高,圆形和X形能量桩的单桩承载力均增大;(2)在45 ℃热循环、桩周土压力相同情况下,X形桩的极限承载力和桩土极限位移量均大于圆形桩,在100、200、300 kPa荷载下,X形桩的承载力是圆形桩的176％、134％、125％;(3)综合分析发现,桩形和桩周土压力对能量桩的单桩承载力影响较大。温度升高改变了桩-土界面特性,因此单桩承载力显著提高。X形桩的承载力优势随围压增大而衰减。

Abstract:

To reveal the mechanism of the influence of temperature field, pile shape and soil confining pressure on the bearing capacity of energy piles, a bearing capacity evolution test of energy piles under the combined action of temperature, pile shape and confining pressure was carried out. The results show: (1) With the increase of temperature, the single-pile bearing capacity of both circular and X-shaped energy piles increases; (2) Under the conditions of 45 ℃ thermal cycling and the same pile-side soil pressure, the ultimate bearing capacity and the ultimate displacement of X-shaped piles are greater than those of circular piles. At loads of 100, 200 and 300 kPa, the bearing capacity of X-shaped piles is 176%, 134% and 125% of that of circular piles; (3) Comprehensive analysis reveals that the pile shape and the pile-side soil pressure have a significant impact on the single-pile bearing capacity of energy piles. The increase in temperature changes the characteristics of the pile-soil interface, thus significantly improving the single-pile bearing capacity. The bearing capacity advantage of X-shaped piles decreases with the increase of confining pressure.