锚桩竖向荷载抗拔模型试验研究

Model Studies of the Uplift Capacity of Plated Ground Anchors

为研究锚桩上拔过程中锚身及桩周土体变化机制,进行了室内模型试验;基于模型试验结果,提出了锚-桩效应理论。锚桩效应是指在上拔过程中锚桩在一定砂土密实度中锚板与桩之间的相互作用对整体结构锚固效果的影响。试验结果表明,锚桩工作过程中峰值荷载并不是简单的锚板与桩单独上拔锚峰值荷载之和,锚桩在浅埋松砂状态下的极限抗拔承载力为锚板与桩单独工作的149.0%;而在密砂深埋下极限抗拔承载力是其单独工作的93%;说明埋深、密实度对锚桩效应具有显著影响,且两种影响因素互相组合叠加。

Laboratory model tests were conducted to study the movement of ground anchor and its surrounding soils under the uplifting load. An anchor-plate theory is proposed base based on the test results. The anchor-plate effect is the interaction between the anchor plate and the anchor in the sandy soils. The results indicate that, the peak uplift resistance is not simply the summation of the resistances of the anchor plate and the grouted shaft of the anchor. Under shallow embedment condition in loose sand, the ultimate resistance of the plated ground anchor is 149% of the ultimate capacity of anchor plate or anchor shaft alone. Under the deep embedment in dense sand, the ultimate capacity of the plated anchor is only 93% of the single component resistance from the anchor or shaft. It is therefore indicated that the relative density of the sand, and the plate embedment depth have significant influence on the plated ground anchor uplift resistance and the interaction of both factors are important.