沉埋式双排抗滑桩加固滑坡承载机理研究

为探究沉埋式双排抗滑桩(沉埋式后排桩和全长式前排桩的组合形式)的承载机理,采用土压力盒和应变片完成一系列室内模型试验,在外界施加的滑坡推力作用下,量测桩身内力变化与桩周土体压力的变化情况,研究桩身受力的分布形式和土拱效应,并分析后排桩长度变化时的双排桩的受力变化规律。研究结果表明,沉埋式双排抗滑桩的受力方式不同于全长双排抗滑桩的受力方式:沉埋式抗滑桩前排桩桩后推力分布形式为梯形分布,桩前抗力分布形式为矩形分布;后排桩桩后推力分布形式呈梯形分布,桩前抗力分布形式为倒梯形分布。后排桩的沉埋深度对前排桩的土拱效应有着较大的影响,并且分析认为当前后排桩承载比较接近时的沉埋深度为设计沉埋深度。为进一步探究排距对沉埋深度的影响,运用FLAC3D,探讨不同排距下双排桩的承载比。研究结果表明,随着排间距增大,后排桩的设计沉埋深度逐渐减小。

Study on the Bearing Mechanism of Deeply Buried Double-row Anti-slide Piles in Landslide Control

To explore the bearing mechanism of the deeply buried double-row anti-slide pile(the combined form of buried back-row pile and full-length front-row pile), a series of laboratory model experiments are carried out using earth pressure cell and strain gauge, the changes of the internal stress of the pile body and soil pressure around the pile under the action of external landslide thrust are calculated, the distribution of the pile body stress and the soil arching effect are studied, and the stress variation law of the double-row pile subject to the changes of the rear pile length are analyzed. The research results show that loading mode of the deeply buried double-row pile is different from that of the full-length double-row anti-slide pile: the pressure distribution form of the soil pressure behind the fore pile is a trapezoid, and that of the resistance of soil is a rectangle; the distribution of soil pressure behind the rear pile is in the form of a trapezoid basically, and that of the resistance of soil is in the form of a trapezoid. The depth of the rear pile has a great influence on the soil arching effect of the fore pile. To further explore the influence of row spacing on the burying depth, FLAC3 D is used to identify the load ratio of double-row piles under different row spacing. The results demonstrate that the design depth of the rear pile decreases gradually with the increase of row spacing.