摘要
基于上海地区某工程中现场足尺试桩试验结果,针对常规液压振动锤和免共振液压振动锤沉贯的开口钢管桩,开展了抗压极限承载特性及对应的承载力预测方法研究。通过对静载试验实测数据和部分规范提出的桩基抗压极限承载力预测结果进行比较发现:桩基实测承载力小于按照上海规范推荐的预制桩承载力计算方法预测得到的振沉钢管桩抗压极限承载力。其中对于上海地区典型的黏性土中的休止期为40天左右的钢管桩,振沉施工导致的承载力折减约为30%,而振沉施工对以砂性土为持力层的休止期为59天的钢管桩承载特性影响相对较小,故应在振沉钢管设计中考虑振动沉桩对桩基抗压承载特性的影响。此外,沉桩结束休止40天后,实测免共振锤沉桩承载力较常规液压振动锤施工的钢管桩承载力低约11%,这很可能是不同振动锤沉贯钢管桩过程中对桩周土体的扰动差异所致,因此应进一步研究不同振动锤沉贯钢管桩过程对桩周土体扰动及土阻力的影响。
Based on the results of full-scale field tests on three open-ended steel pipe piles driven with vibratory hammers in Shanghai,axial response to compression and design methods were investigated for these test piles.Comparison of bearing capacities between measured and calculated by current standards shows that:measured capacities for these three test piles are lower than values calculated with Shanghai Foundation design code,e.g.for piles in clayey soil dominated ground,after 40 days set-up period,vibratory induced capacity reduction is about 30%;however,this effect is negligible for piles toed in sandy soil with a set-up period of 59days.So vibratory effect should be accounted in design of steel pipe piles driven with vibratory hammers.In addition,after a setup period of 40 days,measured capacity on the pile driven with resonance-free vibratory hammer is about 11%lower than that by non-resonance-free hammer,which may be induced by the difference in disturbance of ground soil around these piles driven with various vibratory hammers.Therefore,further study need to be performed to investigate vibrator hammers’effect on soil disturbance and resistance on steel piles.
作者
曾英俊
包晨茜
李卫超
ZENG Yingjun;BAO Chenxi;LI Weichao(Shanghai Urban Construction Municipal Engineering(Group)Co.,Ltd.,Shanghai 200065,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)
出处
《结构工程师》
2022年第4期121-127,共7页
Structural Engineers
基金
国家自然科学基金资助项目(41972275)。
关键词
振动锤
钢管桩
现场试验
抗压承载特性
承载力
vibratory hammer
steel pipe pile
field test
compression response
bearing capacity
