沉桩挤土对预制抗拔桩承载力影响的模型试验研究

为研究砂性土中沉桩挤土对预制抗拔桩承载特性的影响,开展了预制抗拔桩在非挤土、单桩挤土条件下的室内模型试验,对比分析了挤土程度、桩长及桩间距等因素对模型桩的抗拔承载力、桩顶位移及挤土范围等方面的影响。结果表明:在砂性土中不同挤土条件下,预制模型桩的极限抗拔承载力与桩长呈正相关关系;在单桩挤土试验中,试验桩极限抗拔承载力显著大于非挤土条件下对应的数值,且随着桩间距的加大,挤土强度削弱,试验桩的极限抗拔承载力随之减小,并逐渐接近非挤土条件下的承载力数值。

Study on model tests of pile driving effects on the anti-lifting bearing capacity of precast uplift pile

In order to study the pile driving effects on the anti-lifting bearing capacity of precast uplift pile in sand soil, the author respectively conducted a series of model tests of precast uplift pile under the different conditions such as the non-squeezing soil and the single pile squeezing soil, to compare and analyze the effect of different pile length and space on the uplift bearing capacity, displacement of pile tip and the scope of soil squeezing which is under different conditions of squeezing effect. Through the analysis, there is positive correlation between the anti-lifting bearing capacity of precast uplift pile and pile length; The extreme limit of anti-lifting bearing capacity of the model piles which under squeezing effect of single pile is larger than the one that is under non-squeezing effect condition. With the pile spacing increasing, squeezing effect is weakening, that result in the extreme limit of anti-lifting bearing capacity of the model piles decrease. Finally it approached the experimental value that under non-squeezing effect condition.