小直径超深嵌岩灌注桩侧阻力现场试验研究

主要针对小直径超深嵌岩灌注桩嵌岩段侧阻力进行分析研究。在单桩竖向静载荷试验中,在桩身分层预埋钢筋计和应变计,测读各级荷载作用下桩身内力值,对嵌岩段侧阻力的发挥机制进行分析。结果表明:桩身内力是由上至下逐渐开始发挥的,对于超深的嵌岩桩,桩端阻力发挥比例极小。桩身侧阻力随着荷载的增加不断地变化,上部侧摩阻力先发挥,并且在每级荷载作用下,桩侧摩阻力都有传递。受桩端岩层的影响,嵌岩段靠近桩端部分的侧阻力要高于远离桩端的侧阻力。嵌岩段侧摩阻力分布曲线整体呈双驼峰形,下部峰值高于上部峰值,且在桩顶荷载传递过程中,最大峰值有下移的趋势。

Field Test Research on the Side Resistance of Small Diameter Ultra-Deep Rock Filling Pile

This paper mainly aims at the analysis of the side resistance of the rock-socketed of small diameter and ultra-deep rock-socketed filling pile. In the vertical static load test of single pile, steel bar meters and strain gauges were embedded around the pile by layering, and the value of internal force of pile was measured, to analyze the mechanism of the side resistance of the rock-socketed. The results indicate: the internal force of pile begin to play gradually from top to bottom. It was conformed that pile-end resistance work in a small proportion for the ultra-deep rock filling pile. In the process of vertical loading transfer, the side resistance of pile worked gradually begin with the upper pile, and then transmitted downward along with each stage loading. The side resistance of the rock-socketed near pile bottom higher than that far from pile bottom did, which was influenced by the rock stratum in the pile end. The distribution curve of rock-socketed segment side friction is double hump shape curve on the whole, and the lower peak is higher than the upper. At the top of the pile load transfer process, the maximum peak has a tendency to move down.