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通过深厚软土地区的某个超高层建筑大直径钻孔桩静载试验,实测每级荷载作用下的桩身应力、桩顶沉降量及桩端沉降量等参数,分析了软土中持力层为卵石的超长桩的承载性状和荷载传递机理,结果表明:桩侧摩阻力和桩端阻力的发挥是个异步过程;桩侧摩阻力会出现不同程度的弱化现象;靠近桩端的桩侧摩阻力不仅有弱化现象,还有强化现象;桩端注浆效果越好的桩,单位体积承载力越大。为了充分发挥桩身下部土层的桩侧摩阻力和桩端阻力,并减少桩侧阻力弱化现象,桩基设计时可适当提高桩身砼设计强度,增大桩身刚度,减少桩身压缩量,或者在持力层条件合适下采用桩底高压注浆技术。
Through the static load test of large-diameter bored pile in a deep-thick soft soil area, the pile stress, pile-top settlement and pile-end settlement under each load are measured. The results show that the friction on the pile side and the resistance on the pile tip are an asynchronous process, and the frictional resistance on the pile side will be weakened to some extent. The side friction near the pile end Resistance is not only weakened phenomenon, there is the phenomenon of strengthening; pile tip grouting better, the greater the unit volume bearing capacity. In order to give full play to the pile-side friction and pile-end resistance of the soil under the pile body and reduce the weakening phenomenon of the pile-side resistance, the design strength of the pile can be appropriately increased, the rigidity of the pile body is increased, , Or in the stratospheric conditions suitable for the use of pile bottom high pressure grouting technology.