不同水平偏心距下群桩内力变化规律试验研究

TEST INVESTIGATION ON DISTRIBUTION OF INTERNAL FORCES IN PILE GROUPS UNDER DIFFERENT LATERAL ECCENTRICITIES

为研究不同偏心距下水平加载群桩性状和内力分配规律,开展饱和粉土中2组3×3钢管桩群桩(偏心距分别为e=11D和6D,D为桩径)大尺寸模型试验。试验结果显示,扭矩荷载和水平荷载存在着显著耦合效应,外加扭矩显著降低群桩水平承载能力;群桩中,各基桩桩头内力表现出明显的差别,少数基桩承担大部分荷载,且随着偏心距增加,差别更加明显;桩头水平剪力与扭转抗力对抵抗外加扭矩都发挥着重要作用,随着外荷载的增加,水平剪力所占比重明显增大。

Two large-scale model tests on 3×3 pile groups under lateral loading with different eccentricities（e=6D and e=11D,D is pile diameter） in saturated silt are conducted to investigate the law that the applied loads are transferred in the pile groups.The load-displacement curves of the pile groups indicated that an applied torque significantly decreases the lateral resistance of the pile groups.Both lateral and torsional resistances of the individual pile were simultaneously mobilized to resist the applied load.It is found that the lateral and torsional resistances,and in turn,the bending moments,of the individual pile are significantly different;and the difference becomes larger as the eccentricity increases.Both torsional and lateral resistances of the individual pile contribute to resist the applied torque;and the contribution of torsional resistances of the individual pile to the applied torque significantly decreases with the increase in applied load.