后注浆灌注桩单桩承载力影响因素分析及设计取值探讨

Influencing factors analysis and design value discussion of single pile bearing capacity for post grouting piles

通过对实际工程中相同场地条件下相同桩径、桩长抗压基桩在不注浆、仅桩端注浆、桩端桩侧均注浆三种工况下的抗压承载力测试结果对比分析,以及不同桩径、相同桩长、不注浆和不同桩径、不同桩长、桩端桩侧均注浆的抗压基桩承载力测试结果的对比分析,不仅可以得到后注浆灌注桩承载力综合提高系数实测值,而且可分析了解单桩承载力影响因素,为在石家庄地区合理采用侧阻力增强系数、端阻力增强系数,以及合理考虑后注浆桩尺寸效应、桩端土层影响因素等提供工程依据。

Based on the same site conditions,during the actual engineering,compressive piles were selected with the same diameter and length to conduct tests. Compressive bearing capacity test results under three kinds of working condition of no-grouting pile,grouting at the both ends of the pile and grouting at lateral and both ends of the piles were obtained and analyzed. And test results of the compressive bearing capacities of the no-grouting compressive piles with the different diameters but the same length were obtained and compared with results of compressive piles with grouting at lateral and both ends as well as different diameters and lengths. The measured values of comprehensive increasing coefficient of bearing capacity for post grouting piles were obtained,and the influencing factors on the single pile bearing capacity were also analyzed and mastered. All of these provide engineering basis for rational use of enhancement factor of lateral resistance of the pile,enhancement factor of the end resistance of the pile and reasonable consideration on size effect of post grouting pile and influencing factors of pile end soil in Shijiazhuang area.