挖孔灌注桩结合静压钢管桩在某地下车库基础止沉加固中的应用

Application of Digging-Hole Cast-In-Place Pile with Static Pressure Steel Pipe Pile in Reinforcement of an Underground Garage Foundation

位于湿陷性黄土场地某地下车库桩基出现持续不均匀沉降,导致该地下车库部分柱竖向位移过大,相邻柱沉降差超过规范限值。为了制止该地下车库桩基的沉降,首先对其进行了检测与鉴定,找到不均匀沉降的原因,再有针对性制定对于一桩一柱基础的加固方案,在原桩基的一侧新增挖孔灌注桩并增大承台进行加固,同时在偏心加固灌注桩的对面采用三根静压钢管桩加固在承台底,既增强了加固效果,又增大了安全储备,同时避免了只有一根灌注桩加固后产生的承载偏心,相比“二牛抬杠”加固方案节约工期和投资。

The pile foundation of an underground garage located in collapsibility loess site has sustained uneven settlement,resulting in excessive vertical displacement of some columns of the underground garage and settlement difference of adjacent columns exceeding the standard limit.In order to stop the settlement of pile foundation of the underground garage,it is first tested and identified to find out the cause of uneven settlement,and then a strengthening scheme for pile and column foundation is formulated.A newly dug cast-in-place pile is added to one side of the original pile foundation and the cap is enlarged for reinforcement.Meanwhile,three static pressure steel pipe piles are used to reinforce the bottom of the cap on the opposite side of the eccentric reinforcement pile.It not only enhances the reinforcement effect,but also increases the safety reserve.At the same time,it avoids the bearing eccentricity caused by the reinforcement of only one cast-in pile.Compared with the“The two oxen raised the bar”reinforcement scheme,the construction period and investment are saved.