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针对红砂岩嵌岩桩桩-岩界面的摩阻特性进行了现场模型试验。试验研究表明,红砂岩嵌岩桩侧摩阻力呈现上大下小的分布模式,并随着岩石节理裂隙、钻孔质量等因素呈现波动,破坏时桩身上部的侧阻力远大于下部侧阻力值。随着桩长的增加,桩侧摩阻力的发挥效率降低,极限侧摩阻力减小;桩周红砂岩的软化会明显降低极限侧摩阻力和承载力,并改变红砂岩嵌岩的破坏模式;随着桩端刚度的增加,侧阻力分担比变小,发挥速度加快;增加桩长或桩端刚度使侧阻力有向桩身上部集中的趋势。根据现行规范确定的红砂岩嵌岩桩承载力存在较大的安全储备。
A field model test was conducted on the frictional properties of red rock sandstone piles-rock interface. The experimental results show that the side frictional resistance of rockfill embedded in red sandstone exhibits a pattern of large to small distribution and fluctuates with the rock joints, the quality of drilling holes and other factors. The lateral resistance of the upper part of the pile is much larger than that of the lower part . With the increase of pile length, the frictional efficiency of pile side decreases and the friction on the limit side decreases. The softening of the red sandstone on the pile periphery will significantly reduce the ultimate friction and bearing capacity, and change the failure mode of the rock embedded in red sandstone. With the increase of the pile end stiffness, the sharing ratio of side resistance becomes smaller and the playing speed increases; the upper part of the lateral resistance directional pile body tends to increase with increasing pile length or pile end stiffness. According to the current rules to determine the red sandstone rock-socketed pile capacity there is a large safety reserve.