影响钻孔灌注桩承载力的效应和因素

Effects and Factors Affecting Bearing Capacity of Bored Pile

目前在各国家地区设计规范标准中,钻孔灌注桩的承载力计算方法多采用以土体强度为依据的经验公式,通常得出非常保守的下限值,而桩真实承载力的估算难度较大。因此,现场试桩荷载试验作为一种直接量测桩承载力的方式,经常被工程项目实践所采用。借助一线性工程项目的现场试桩试验案例,通过对钻孔灌注桩承载力设计值和实测值的对比分析,探讨解释了导致差异现象的可能效应,归纳梳理了影响桩承载力的因素,为类似现场的钻孔灌注桩桩基工程设计和施工工艺提供经验依据和建议。

At present,in the design codes and standards of various countries and regions,the calculation method of bearing capacity of bored cast-in-place pile mostly adopts the empirical formula based on the strength of soil mass,and usually a very conservative lower limit value is obtained.However,it is difficult to estimate the true bearing capacity of the pile.Therefore,to directly measure the bearing capacity of piles,the field test pile load test is often used in the practice of engineering projects.Based on the field test case of a linear engineering project,through the comparison and analysis of the design value and the measured value of the bearing capacity of bored cast-in-place pile,the possible effects leading to the difference are discussed and explained,and the factors affecting the bearing capacity of the pile are summarized and sorted out,which provides experience basis and suggestions for the design and construction technology of bored cast-in-place pile foundation in similar sites.