英标钻孔桩单桩承载力及沉降计算方法研究

Study on Calculation Method of Bearing Capacity and Settlement of Single Bored Pile by British Standard

不同于国标的桩基承载力计算,英国标准计算单桩承载力是一种半经验-半计算法,目前应用较多的为有效应力法和标准贯入度值(SPT)法,而这2种计算方法需要结合土工试验参数或者原位试验结果,并按照规范给出的经验系数进行计算。分析表明:英国标准中的有效应力法对土工试验参数较为敏感,计算得到的极限承载力变异性较大;SPT法计算得到的极限承载力值较为稳定,且与试桩结果较为符合,在工程设计中建议结合SPT计算法,对有效应力法结果进行修正。

Different from the calculation of pile foundation bearing capacity by the national standard,the calculation of single pile bearing capacity by British standard is a semi-empirical-semi-calculation method.Currently,the commonly used methods are the effective stress method and the standard penetration test(SPT)method.And these two computing methods are required to combine the geotechnical test parameters or in-situ test results,and the empirical coefficients are calculated according to the standards.The analysis shows that the effective stress method in the British Standard is more sensitive to the geotechnical test parameters.The calculated ultimate bearing capacity has greater variability.The ultimate bearing capacity value calculated by the SPT method is more stable and is more consistent with the test pile results.In the engineering design,it is recommended to combine the SPT method to modify the results of the effective stress method.