预应力管桩动测承载力数值分析及参数取值研究

在基桩动测承载力计算时,桩周土动力参数取值未考虑与其埋深的关系、各土层阻尼系数和最大弹性变形值未根据土层性质分别取值进行计算,这与实际情况不相符合。为了使基桩动测承载力计算结果更接近实际情况,通过桩周土动三轴试验,分析动力参数取值与其土层埋深的关系;在Bowles方法的基础上,各土层采用不同阻尼系数,以及各土层采用不同最大弹性变形值,对该分析方法进行改进;通过对典型泥质粉砂岩持力层的12根试验桩进行极限荷载试验,验证和修正该数值计算方法。研究结果表明土层分布尤其是较浅部土层分布对锤击桩时土动力学响应影响较大;改进方法计算基桩动测承载力更为合理。

Numerical analysis and parameter selection of dynamic load-bearing capacity of prestressed pipe pile

In calculation of dynamic load-bearing capacity of foundation piles,the relationship between dynamic parameters of soil around pile and its buried depth is not considered,damping coefficient and the maximum elastic deformation value of each soil layer are not calculated according to soil layer properties,this is inconsistent with the actual situation.Here,in order to make the calculation results of dynamic load-bearing capacity of foundation piles be closer to the actual situation,through dynamic triaxial tests of soil around pile,relations between soil layer’s dynamic parameters and its buried depth were analysed.Based on Bowles method,this analysis method was improved by using different damping coefficients and different maximum elastic deformations for different soil layers.Through ultimate load tests of 12 test piles in typical argillaceous siltstone load-bearing stratum,the numerical calculation method was verified and modified.The results showed that distribution of soil layers,especially,shallow soil layers has a larger influence on soil dynamic response when hammering piles;the improved method is more reasonable for calculating dynamic load-bearing capacity of foundation piles.