桩基模型试验应变测试方法比较

A Comparison of Strain Test Methods of Pile Foundation Models

桩身应变测试是桩基承载性能研究中的一项重要内容,是竖向荷载作用下桩身应力、轴力、侧摩阻力等荷载传递规律分析的基础.基于室内模型试验,采用常规的电阻应变片与光纤布拉格光栅(FBG)两种应变测试方法,对两组单桩在竖向荷载作用下的桩身应变特性做了完整的测试.对比分析试验结果表明:光纤布拉格光栅测得的应变数据具有较高的精度和稳定性,可以绘制更符合客观实际的桩身轴力和桩侧摩阻力曲线.

Pile strain tests are considered essential for pile foundation bearing capacity studies, and are the basis on which such load transfer laws as pile strain, axial force, and side friction under vertical loads are analyzed. Based on laboratory model tests, the two strain test methods, i.e., normal resistance strain gauge method and fiber brag$ grating method, are used to test the pile strain properties of two single piles under vertical loads. The results show that fiber bragg grating method can be used to draw more objective curves of pile axial force and pile side friction, because the strain data derived from fiber bragg grating is more accurate and stable than that from resistance strain gauge.