开孔管桩真空固结提高承载力模型试验

Model experiment on improving bearing capacity of perforated pipe piles by vacuum consolidation

为了研究桩基承载力的增长程度、桩周土的抗剪强度和含水率变化规律、桩周土排水量,开展真空固结模型试验,得到模型桩的Q-s曲线、桩周土的十字板强度和含水率的分布规律、排水量随时间的增长曲线.结果表明,在该试验条件下,开孔管桩真空固结技术可以使桩基承载力提高2.7倍,使桩周形成厚4.5 cm、较高抗剪强度、较低含水率的致密层.研究桩身开孔布置的影响,得出桩基承载力的增长程度受开孔层间距的影响较大,受孔径的影响很小.

Vacuum consolidation model tests were conducted in order to analyze the growth degree in bearing capacity of pile foundation,the variation of shear strength and water content of soil around the pile,as well as the water discharge of surrounding soil.The Q-s curves of model piles and the distributions of vane shear strength and water content of soil around piles,and curves of water drainage with time were obtained.Results show that the vacuum consolidation technology can increase the bearing capacity of pile foundation by 2.7 times under the conditions of the tests,and form a dense layer around the pile,which is 4.5 cm thick with relatively high shear strength and relatively low water content.The influence of holes layout was analyzed.The bearing capacity of pile foundation was greatly affected by the spacing of hole layers,but little affected by dimension of holes.