某桥桥墩桩基偏位纠偏方案设计与实施

Design and Implementation of Deviation Rectifying Scheme for Pile Foundations of Piers of a Bridge

某四跨25m预应力空心板简支梁桥桥墩桩基严重偏位,桩顶最大偏移量为19.1cm。经分析,该桥桥墩桩基偏位的原因为在堆土不平均土压力作用下,淤泥层发生显著的侧向挤出现象,从而产生巨大的侧向推挤作用,使右幅桥墩产生偏移。结合现场实际情况,采取设置应力释放孔、高压旋喷桩,新增桩基承台及顶推纠偏等措施进行纠偏整治,使桥墩偏位回归允许范围内。采用荷载试验对加固后桥墩的承载能力进行评定,结果表明,桥墩承载能力满足设计要求,所采取的方案有效,纠偏效果良好。

The pile foundations for the piers of a 4 × 25-m span prestressed concrete simply- supported hollow slab beam bridge deviated severely and the maximum deviation amount of the pile tops was up to 19.1 era. Through the analysis of the deviations of the pile foundations, it was considered 1hat the causes of the deviations lay in the following： under the action of the non- uniform stacked soil pressure, the problem of significant lateral compaction of the silt layers in the ground occurred, the problem produced enormous lateral pushing action and consequently caused the piers of the right part of the bridge to deviate. In the light of the actual site condi- tions, the measures of arranging the stress releasing holes and high pressure jet grouting piles, adding the new pile caps and rectifying the deviations by pushing were taken to handle the devia- tions of the pile foundations and to restore the deviations of the piers to the allowable range. The bearing capacity of the handled piers was assessed by the load tests and the results showed that that the bearing capacity of the piers could meet the design requirements, the deviation rectifying scheme orepared for the oile foundations and piers was effective and the effect of the deviationrectifying was sound.