三向位移计在桩基测试中的应用

Application of TRIVEC in pile testing

三向位移计是线法监测仪器中的一个代表仪器,能够测定整条测线的应变。通过工程实例展示了三向位移计在桩基摩阻力及端阻力测试中的应用情况。采用四次多项式拟合法对实测应变曲线进行处理,继而得到摩阻力与端阻力。测试结果显示,桩在荷载较小的时候,反力大部分由桩侧摩阻力提供,当荷载增加到一定数值时,端阻力开始出现,此时侧摩阻力增量较小或不再随荷载的增加而增加,端阻力增量却表现得十分明显。桩侧摩阻力峰值位置会随荷载的增加而向桩底方向移动。

TRIVEC is a representative of linear observation equipment that can measure strain in a whole line range.We present the application of TRIVEC in detection of frictional resistance and end resistance in a pile testing projects.Quartic polynomial fitting is applied to process the measured strain data,and then the frictional resistance and end resistance of a pile can be obtained.The result show that,frictional resistance provides a larger part of counter force when load is small,but when the load increases to a higher level,the end resistance begins to appear,and the frictional resistance shows a little increment or even no increment with the increment of load,while the end resistance increases significantly.Moreover,the test verifies a law that the position of peak frictional resistance will move towards the end of the pile with load increases.