大直径扩底短桩单桩承载力试验

某高层建筑的地基持力层分布均匀且埋藏较浅、土层厚度较小,而持力层下部又有较好的土层,经方案比选,决定采用大直径扩底短桩,并通过静载荷试验进行了验证,验证结果表明,试验结果与计算值基本一致,设计是合理可行的。

Axial Capacity Testing on Short Large Diameter Piles with Expanded Base

The soft soil improvement project combined with vacuum preloading and surcharge is summarized in this paper. The conventional pumping termination criterion in the preloading project is the settlement rate equal or less than 5 mm per month. The results in this case study indicate that the criterion is excessively high and is difficult to achieve or at very cost if it can be achieved. This study modifies this criterion by considering the unloading and reloading characteristics of soft soils and the over --consolidation phenomena induced by the removal of the surcharge. The pumping termination criteria can be obtained by con- sidering the allowable post construction settlement of the roadway, even if the settlement rate prior to the pumping termination is greater than the conventional 5mm per month.