为研究滨海地区地下水流动对静钻根植能源桩承载特性影响,制作了1.2 m厚度的软黏土夹砂层模型地基,开展静钻根植能源桩单桩模型试验,测试分析有无水流条件下桩土体系的温度、孔压、位移及应力,结果表明:地下水流动减小了桩身温度变化,其变化范围为6.39%~34.15%;桩周土下游温度变化明显高于上游,温度变化有利于减少能源桩周围土体的热冷堆积效应;水流降低桩侧临近土体中的热孔压约11%,降低负压约20%,并使桩顶累积沉降减小约1/3;地下水流动时还降低了温度引起的桩身拉压应力;随着载荷增大,水流对桩侧摩阻力的影响降低;有地下水流条件下,升降温工况下的负摩阻力最大值均下降,因此有利于静钻根植能源桩的长期工作。
In order to study the influence of groundwater flow on the bearing characteristics of static drilling deep-rooted energy pile in coastal area, a model test system of static drilling deep-rooted energy pile in 1.2 m thick soft clay interlaced with sand model ground was designed, so as to test and analyze the temperature, pore pressure, displacement and stress of pile-soil system with or without water flow. The results showed that groundwater flow reduced the temperature variation of pile, ranging from 6.39% to 34.15%. The temperature change of the downstream soil is obviously higher than that of the upstream soil, which is beneficial to reduce the thermal and cold accumulation effect of the soil around the pile. The water flow approximately reduces the hot pore pressure by 11% and the negative pressure by 20% in the surrounding soil, and the cumulative settlement of pile top is approximately reduced by 1/3. The tension stress of pile body caused by temperature is also reduced when groundwater flows. With the increase of load, the influence of water flow on friction decreases. Under the condition of underground flow, the maximum negative friction decreases under the rising and cooling conditions, which is conducive to the long-term work of static drilling of energy pile.
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