磁梯度法在钻孔桩钢筋笼长度检测中的研究

基桩工程中桩体内部钢筋笼长度是否按设计施工难以验证,以往的测试仪器及测试方法难以给予准确的判定。理论上,钢筋笼长度的变化反映了竖向磁性物理量的变化,因此沿钢筋笼轴向的磁梯度将产生明显的变化。根据这一特点结合某高速公路桩基工程中的应用实例对成桩后测试钢筋笼长度的原理及数据分析方法进行分析。理论分析及实例表明,钢筋笼磁梯度测试曲线与基桩低应变反射波法测试曲线有极其相似的特点。

The Research on the Length Detection of Bored Pile Steel Reinforcement Cage Using the Magnetic Gradient Method

It is hard to validate whether the length of the steel reinforcement cage (SRC) in the pile body interior of foundation pile construction is constructed according to the design, and hard to give an exact judgment with previous test apparatus and method. Theoretically, the change of the SRC length reflects the diversification of the vertical magnetic, so there will be obvious change on the magnetic gradient along the axial direction of the SRC. According to this feature, combined with the practical example of pile founda-tion engineering of some freeway, the paper analyses the theory of SRC length detection and data analysis method. The theory analy-sis and the example indicate that the test curve of the SRC magnetic gradient is extremely similar to the test curve of low-strain reflec-tion wave method.