铁路基桩反射波法完整性检测应用探讨

Discussion on the Applying Reflection Wave Method to Detect the Integrity of Railway Foundation Pile

对使用反射波法检测铁路大直径基桩完整性时,其反射波曲线中浅部会产生1个正向缺陷信号的问题作了详细探讨。经分析,它是由于基桩在冲击成孔或人工挖孔施工中,其桩顶砂浆没有清理干净和人工挖孔桩护壁等原因引起的。所以,在采用反射波法检测基桩完整性时,其桩顶砂浆要清理干净,且露出含有粗细骨料均匀致密呈青色的混凝土新表面,而对于人工挖孔桩的护壁影响因素可在桩体混凝土强度达到设计强度95%时进行检测。这样,就能够消除反射波曲线中浅部的正向缺陷信号,以便正确判定基桩完整性。

The authors analyze the problem that there will be a positive defect signals in the shallow curve of the reflected wave when the reflection wave method is used to detect the integrity of large diameter railway piles.The analysis shows that the problem is due to the left mortar on the tope of the piles and the wall protection of the handdug hole piles in the process of impact-shock hole forming or hand-dug hole forming.Thus,when the reflection wave method is used to detect the integrity of foundation piles,the mortar on the tope of piles must be cleaned up and the fresh surface containing uniform and dense concrete material,and the color is green.The influence factors of the wall protection of the hand-dug hole piles could be detected while the concrete intensity reaches 95% of the design intensity.By doing so,we can eliminate the positive defect signals in the shallow curve of reflected waves,to correctly determine the integrity of the piles.