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为了研究冻土区桩底水对桩基稳定性的影响,制作混凝土模型桩及桩底水热效应装置并采用对比试验方法对模型桩顶逐级加载开展桩底水热效应对冻土桩–土流变特性影响的模型试验研究,得出桩身切向冻结应力传递函数曲线及桩端阻力传递函数曲线,分析不同荷载等级下桩底水对桩土相对位移及桩端阻力,桩–土流变特性,荷载传递特性,桩基承载特性的影响。结果表明:桩底水的作用减弱了冻土桩侧冻结强度及桩端地基土的抗力,造成桩土相对位移过大,加大了桩–冻土的流变效应,影响了桩侧冻结力和端阻力承担荷载的比例而使得桩基过分依靠桩侧切向冻结力来承受荷载且上述作用随着荷载的增大而增大,造成桩基承载力严重下降。
In order to study the influence of pile-bottom water on the stability of pile foundation in permafrost region, a concrete model pile and a pile-bottom hydrothermal effect device are made and the pile-top hydrothermal effect is carried out step by step by contrast test. The model test of the influence of the deformation of the pile body is carried out. The curve of the stress transfer function of the pile body and the transfer function curve of the pile tip are obtained. The influence of the pile bottom water on the relative displacement of pile and soil, Characteristics, load transfer characteristics, pile foundation bearing characteristics. The results show that the effect of bottom water weakens the freezing strength of pile tip and the resistance of foundation soil, resulting in excessive displacement of pile-soil, increasing the rheological effect of pile-frozen soil and affecting the freezing force And the ratio of the end-bearing load, the pile foundation is overloaded by the tangential freezing force of the pile to bear the load, and the above-mentioned action increases with the increase of the load, resulting in a serious decrease of the bearing capacity of the pile.