卵石地层中钻孔灌注桩成桩质量问题分析

Analysis on Quality Problems of Bored Piles in Pebble Stratum

在济南西郊山前冲洪积层地区,18层以上的高层建筑均采用桩筏基础,其中桩基础采用钻孔灌注桩,持力层选择在卵石层或砂层上。粗粒土层因其承载力高通常被认为是良好的桩端持力层,但由于其缺乏粘聚力,施工过程控制不严也会带来桩基质量方面的问题。通过对工程实例的分析,探讨卵石地层中钻孔灌注桩质量问题的原因,提出相应的防治措施,为类似工程提供借鉴。

In the Piedmont Alluvial-diluvial zone in the western suburb of Jinan,piled raft foundation is used for high-rise buildings above 18 stories,in which bored piles are used for pile foundation,and the bearing layer is chosen on pebble or sand layer.Coarse-grained soil is usually considered as a good pile-end bearing stratum because of its high bearing capacity.However,due to its lack of cohesion,quality problems of pile foundation is also occurred without strict control of construction process.Through a case history of a bored cast-in-place pile foundation,the causes of quality problems of bored piles in pebble stratum are discussed,and corresponding prevention measures are put forward,which can provide reference for similar projects.