利用SPT和PDA评估强风化花岗岩中桥梁钢管桩的端阻力  

Evaluation of End Resistance of Bridge Steel Pipe in Strongly Weathered Granite by Using SPT and PDA

作　　者：李新强[1] Li Xinqiang(Sinohydro Bureau 5 Co.,Ltd.)

机构地区：[1]中国水利水电第五工程局有限公司,成都市610066

出　　处：《勘察科学技术》2024年第1期20-25,共6页Site Investigation Science and Technology

摘　　要：该文根据钢管桩的贯入机理,分别采用算术平均方法和几何平均方法,研究了桩身范围内SPT(标准贯入试验)平均值与PDA(打桩分析仪)测得的桩端承载力的关系,得出如下结论:1)桩基发生冲击破坏时,桩身周围存在一个屈服区,屈服区以内土体的SPT击数才能反映桩基承载力大小;2)桥梁钢管桩屈服区范围较大,SPT统计数据多,采用算术平均方法能更真实地估算桩基承载力;3)对于强风化花岗岩,桩端承载力影响深度范围内的标贯击数算术平均值最能反映桩端阻力,此时桩端承载力发挥较为充分。该文提出的标贯击数与桩端极限承载力的关系式,为现场其它钢管桩的端阻力评估提供了依据,节约了桩基承载力测试成本。This paper studies the relationship between the average value of SPT(Standard Penetration Test)within the pile range and the pile end bearing capacity measured by PDA(Pile Driving Analyzer)based on the penetration mechanism of steel pipe piles by using arithmetic mean method and geometric mean method respectively.The conclusions are as follows:1)When impact damage occurs to a foundation,there is a yield zone around the pile body,and the SPT hits of the soil within the yield zone can reflect the bearing capacity of the pile foundation;2)The yield zone of bridge steel pipe piles is relatively large,and there are many SPT statistical data,the arithmetic mean method can more accurately estimate the bearing capacity of pile foundations;3)For highly weathered granite,the arithmetic mean of standard penetration tests within the depth range affected by pile end bearing capacity can best reflect the pile end resistance,and at this time,the pile end bearing capacity is fully utilized.The relationship between the number of standard penetration tests and the ultimate bearing capacity of pile ends proposed in this paper provides a basis for evaluating the end resistance of other steel pipe piles on site,saving the cost of pile foundation bearing capacity testing.

关 键 词：标准贯入试验 钢管桩 桩端承载力 算术平均值 几何平均值 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]