考虑不同岩土抗力的加锚双排桩受力变形计算

Stress calculation and analysis of double row pile supporting structure with anchor in deep foundation pit considering pile anchor cooperation

针对已有加锚双排桩计算模型对桩后滑裂面以下岩土层抗力处理的不足,考虑桩锚协同并将剪切滑裂角折减确定了滑裂面位置。然后将作用在前后排桩滑裂面以下的岩土抗力参数进行分段计算,最后采用分段坐标法推导建立了前后桩桩体挠度微分方程,并与成都音乐厅基坑现场监测数据进行了对比。结果表明:该模型计算结果与实测结果较为吻合,特别是对后排桩的受力分析使后排桩桩身位移曲线更贴合实测结果;剪切滑裂面位置对桩体变形影响较大,当剪切滑裂角按1.29的折减系数计算时桩身位移更贴近实测数据。

In view of the deficiency of the existing calculation model of anchored double row pile in dealing with the resistance of rock and soil layer below the sliding surface behind the pile,the position of the sliding surface is determined by considering the coordination of pile and anchor and reducing the shear sliding angle.Then,the geotechnical resistance parameters acting below the sliding surface of the front and rear rows of piles are calculated in sections.Finally,the differential equation of the deflection of the front and rear piles is deduced and established by using the piecewise coordinate method,and compared with the field monitoring data of the foundation pit of Chengdu concert hall.The results show that the calculated results of the model are in good agreement with the measured results,and especially the stress analysis of the rear pile makes the displacement curve of the rear pile more consistent with the measured results.The position of the shear slip surface has a great influence on the pile deformation.When the shear slip angle is calculated according to the reduction coefficient of 1.29,the pile displacement is closer to the measured data.