泥皮对灌注桩摩阻性能影响的模型试验研究

Model test study on influence of mud cake on friction performance of pouring pile

通过室内模型模拟益马高速公路典型砂卵石地层摩擦桩,开展泥浆护壁摩阻试验,研究桩侧和桩端阻力在各级荷载下的分布规律;针对不同泥浆护壁条件,对比分析不同膨润土浓度、不同添加剂种类与浓度条件下泥皮对桩侧摩阻力的影响。试验结果表明:当泥浆浓度大于12%时,桩侧摩阻力会降低30%以上,建议施工过程中成孔时泥浆膨润土浓度不宜超过9%;水泥作为泥浆添加剂会有效优化泥浆性能,改善桩基的荷载-沉降性状,降低泥浆对桩侧摩阻力的影响。

Through the medium sand chamber in the drilling of the grouting pile mud wall indoor model test, the distribution trend and distribution law of pile end and pile side resistance at all levels were studied;for different mud wall conditions, the effects of different clay concentrations, different additive types and concentration on the friction resistance of the mud on the pile side were compared and analyzed. The result shows that the pile side friction will be reduced by more than 30% when the mud concentration is greater than 12%, it is recommended that the concentration of bentonite during construction should not exceed 9%. When the cement as a slurry additive, the mud performance can be effectively optimized, the load-sedimentation behavior of the pile can be improved, and the influence of the mud on the pile-side friction can be reduced.