基于能量法的超长桩屈曲稳定影响因素分析

随着大型超高层建筑的发展,超长桩的使用越来越多,超长桩的屈曲稳定性问题研究显得尤为重要。在前人的基础上,采用土抗力与实际更为接近的C法和常数法组合的土抗力模式,且同时考虑桩自重和桩侧摩阻力,用能量法求解得到超长桩的屈曲临界荷载公式,并进一步全面分析各因素对超长桩屈曲稳定的影响。结果表明:桩侧单位摩阻力与桩身自重对桩的屈曲影响可忽略不计;桩的挠曲函数项数越多、土抗力越小,基桩的屈曲临界荷载越小;桩自身参数桩长、桩径越大,屈曲临界荷载力越大;地基土比例系数越大,屈曲临界荷载越大。因此,从超长桩的屈曲稳定性来讲,尺寸较大的超长桩运用到较硬地基时基桩抵抗屈曲破坏的性能最大。研究成果可为工程中超长桩的设计和运用提供理论依据。

Parametric Analysis of Buckling Stability of Extra-long Pile Based on Energy Method

The buckling stability of extra-long pile which has been increasingly used in high-rise buildings has emerged as a crucial engineering issue. In this research, the formula of critical buckling load of extra-long pile is acquired via energy approach by establishing a model in which the soil resistance is calculated by combining the C method and the constant number method. The self-weight together with side frictional resistance of pile is taking into consideration. Furthermore, the impacts of influential factors on the buckling stability are examined. Results reveal that the influences of unit side friction and self-weight of extra-pile are negligible. The more the number of flexural function items and the smaller the soil resistance, the smaller the buckling critical load is; the larger the pile length and diameter, the larger the buckling critical load is; and the larger the ground soil proportion coefficient, the greater the critical buckling load is. Therefore, in terms of the buckling stability of extra-long pile, large-size extra-long piles have the greatest performance against buckling failure when applied to hard foundations.