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针对大型炼厂工程软弱地基处理的复杂性,完成了不同桩径、是否嵌岩条件下水平、抗压及抗拔钻孔灌注桩的现场试验,试验内容包括钻孔灌注桩施工后的低应变动力检测、钻芯试验、桩身内力测试及单桩静载荷试验。基于低应变动力检测和钻芯试验结果,分析了桩身质量及完整性;通过大量桩身内力测试结果,详细分析了抗拔和抗压试桩在各级竖向荷载作用下轴力和侧摩阻力变化及传递特征,详细分析了抗水平桩在各级水平荷载作用下内力和弯矩变化规律;基于载荷试验结果,分析了单桩水平、抗拔及抗压承载能力;此外,利用试桩水平和抗拔静载荷试验结果,通过散点拟合,建立抗拔承载力特征值的平均值与桩径和单桩水平极限承载力的平均值与桩径的估算公式。研究结果表明:弯矩最大位置随推力增大而逐渐下移,在最大水平推力下,Φ600,Φ800和Φ1 000mm桩弯矩最大点位于推力点以下3.6,4和5m左右;单桩抗拔承载力极限值的平均值与桩径和水平承载力特征值的平均值与桩径均成线性关系。
In view of the complexity of the treatment of soft foundations in large-scale refinery projects, the field tests on horizontal, compressive and anti-pull-bored cast-in-place piles under different pile diameters and under rock-fill conditions were completed. The test contents include the low strain Dynamic test, core drill test, pile internal force test and single pile static load test. Based on the results of low-strain dynamic test and core-drilling test, the pile mass and integrity were analyzed. Through a large number of pile internal force test results, the axial force and side The change of frictional resistance and the transmission characteristics are analyzed in detail. The variation of internal forces and bending moments of horizontal piles under horizontal loads at all levels are analyzed in detail. Based on the load test results, the horizontal piles, anti-pull and compressive bearing capacity are analyzed. In addition, Pile level and static pull load test results, through the scatter fitting, establish the average value of the bearing capacity and pile diameter and single pile ultimate bearing capacity of the average and pile diameter formula. The results show that the maximum position of bending moment decreases gradually with the increase of thrust force. Under the maximum horizontal thrust, the maximum moment of Φ600, Φ800 and Φ1000mm pile bending moment is about 3.6, 4 and 5m below the thrust point. The average value of force limit and the average value of pile diameter and horizontal bearing capacity eigenvalue are linear with pile diameter.