基于静载试验的花岗岩持力层上覆厚层软土基桩弹性压缩分析

Analysis of Elastic Deformation of Deep Foundation Piles in Thick Soft Soil Layer Overlying Granite Bearing Layer Based on Vertical Compression Static Load Test

为使厚层软土地区花岗岩等“硬岩”为持力层的超长灌注桩的桩身弹性压缩量计算更加合理,通过对该类场地灌注桩抗压静载试验“荷载-沉降”数据进行分析,并采用有限元仿真计算和概率统计分析方法,得到了端阻比与长径比等参数的函数关系以及桩侧摩阻力分布系数的样本统计值,建立了通过长径比等参数估算桩身弹性压缩系数ξe的方法以及相应的简化计算公式。最后通过某案例计算与规范推荐的方法进行对比,验证该公式计算桩身弹性压缩量的准确性及便捷性。

In order to calculate the elastic compression of the pile body of ultra-long bored piles with hard rocks such as granite as the load-bearing layer in thick soft soil areas more reasonably,the"load-settlement"data of compression static load tests of bored piles in this type of site were analyzed.By using finite element simulation and probability statistical analysis methods,the functional relationships of parameters such as end bearing ratio and length-to-diameter ratio,as well as the sample statistical values of pile side friction distribution coefficients were obtained.A method for estimating the elastic compression coefficientξe of the pile body based on parameters such as length-to-diameter ratio was established,along with a corresponding simplified calculation formula.Finally,through a case study comparing the calculated results with recommended methods in standards,the accuracy and convenience of the formula for calculating the elastic compression of the pile body were verified.