基桩低应变波速的量值研究

Study on Quantity of Wave Speed in Low Strain Integrety Testing of Foundation Pile

在应力波反射法测试基桩完整性的过程中,应力波波速是确定桩长和桩身缺陷位置的必要条件,而应力波波速受多种因素影响很难准确定量,这已成为基桩测试技术发展的瓶颈.根据应力波传播的基本原理,结合试验研究,分析了应力波在基桩中传播速度的影响因素,得出了应力波传播波速与混凝土龄期和混凝土强度等影响因素之间的量值关系,并结合工程实际提出了5种确定低应变波速的简便实用方法,以便检测人员更好地控制桩基工程质量.

The stress wave speed is the necessary condition to make sure pile length and pile defects position in low strain integrety testing of foundation pile with the stress wave echo method. Quantifying the stress wave speed is very difficult, because it is affected by multi-factors. This has been the bottleneck in point for develo- ping test technology of foundation pile. In this paper, some factors affecting the stress wave speed were ana- lyzed according to stress wave theroy and experiment results, the quantity relationships of the stress wave speed in pile and time and concrete age were determined. Lastly, five brief methods to quantifying the stress wave speed in pile were presented to control pile quality for test engineers according engineering practice.