临近斜坡静压沉桩过程中边坡动态稳定性研究

摘要

基于Bishop圆弧滑动法,根据坡顶静压沉桩过程中桩端阻力、桩身摩阻力对边坡的反作用及沉桩过程中桩周土体强度的变化,并考虑桩体通过边坡潜在滑动面后的抗剪力,提出了静压沉桩过程中边坡动态稳定性的计算方法.结果表明:静压沉桩过程中边坡稳定安全系数随桩入土深度的增加而逐渐减小,当桩端到达边坡潜在滑动面时其安全系数最小,随后由于桩的抗剪力,边坡稳定安全系数显著增大,且逐步趋于稳定.压桩过程中产生的桩端和桩身对边坡的作用力是造成边坡稳定性降低的重要因素;土体超固结比和有效内摩擦角越大,沉桩过程中边坡稳定安全系数越大;桩径越大、桩间距越小,边坡稳定安全系数变化幅度越大.%Based on the simplified Bishop method,in consideration of the force acting on the slope from the pile tip and the pile draft during static piledriving on the top of slope as well as the influence on the soil shear strength by the pile,considering shear strength of the pile after the pile drives through the dangerous slip surface,a closed solution of safety factor of the slope dynamic stability during the static piledriving is derived.The results show that during the static piledriving the safety factor of the slope decreases gradually,and the minimum of the safety factor of the slope comes as the pile tip arrives at the dangerous slip surface,then the safety factor of the slope increases obviously due to the shear strength of the pile and gets to stability in the end.The force acting on the slope from the pile tip and the pile draft produced during the static piledriving are important factors decreasing the stability of the slope;if the effective internal friction angle and the over consolidation ratio of the soil are larger,the safety factor of the slope will be larger;the safety factor will change in a large range on condition of a large pile radius or a small pile spacing.