较破碎岩体中桩基竖向承载力分析与探讨

Analysis and Discussion on Vertical Bearing Capacity of Single Pile in Broken Rock Foundation

较破碎岩体中桩基设计时往往被视为端承桩,不计桩侧阻力,使得桩基承载力未能得到充分利用,因此,需对其进行更深入的研究。以贵州某地区嵌岩桩为研究对象,地基持力层岩体为较破碎岩体,通过单桩竖向抗压静载荷试验,分析较破碎岩体嵌岩桩竖向承载力,探讨较破碎岩体中桩基的承载特性。研究结果表明：较破碎岩体嵌岩桩嵌岩段桩侧摩阻力发挥较好,且在同一岩性中因成分不同其值各有差异。根据实测结果,结合经验参数计算,桩基竖向承载力实测值为计算值的4.2-5.5倍。由此可见,较破碎岩体中嵌岩桩的侧摩阻力十分可观,若按端承桩设计,会创成工程成本增加。成果可为较破碎岩体中桩基设计提供参考。

Pile socketed in broken rock is often regarded as end bearing pile with no regard to the side frictional resistance, so that the bearing capacity of pile foundation is not fully utilized. In this research, the vertical bearing capacity of socketed pile in broken rock is analyzed, and the load-bearing performance of pile foundation in broken rock is discussed based on vertical static load test on single pile. The socketed pile of broken foundation rock of a project in Guizhou province is taken as an engineering background. Results show that the side friction of pile segment socketed in rock plays a good role in load-bearing, and the value of side friction varies with different pile components in the same lithology. According to the test results and parameter calculation, the measured vertical bearing capacity of pile foundation is 4.2-5.5 times as high as the calculated value. As we conclude that the side friction of socketed pile in broken rock is remarkable, if it is designed as end-bearing pile, the engineering cost will increase.