竖向透射法长桩完整性检测新技术研究

Research on the Vertical Logging-a New Technology of Long Pile Integrity Test

研究目的:目前常用的基桩完整性检测方法有低应变反射波法和声波透射法,对于长桩的检测均有其局限性。高速铁路桥梁基础多采用桩基,第四系松散地层中大多为长桩,针对长桩桩身完整性检测,开发一种新的桩身完整性检测方法以弥补现有方法的不足。研究结论:(1)提出了一种新的检测方法——竖向透射法,该方法能可靠地接收来自桩体深部的弹性透射波信号,检测桩长度可达70 m;(2)提出了计算桩身弹性透射波波速、波幅相对衰减和频率的方法;(3)提出的竖向透射法,该方法在长度超过50 m的126根桩上进行了试验,均能检测到桩底透射信号,效果良好,能在一定程度上解决长度超过40 m的长桩桩身完整性检测难题;(4)该研究成果可应用于土木工程桩基检测领域。

Research purposes： Currently, low- strain integrity testing and cross -hole sonic logging have been universally applied for testing integrity of pile, but these two methods have their limits for testing long pile integrity. The long piles, which are constructed in the loose layer of the quaternary, are used widely in the foundation of bridge in high - speed railway. According to the integrity test of long concrete pile, a new test method has been studied to remedy the limitation of the existing method. Research conclusions：（ 1 ） A new test method, vertical logging, has been presented in this paper. The elastic wave of vertical logging transmitted from the deep pile can be reliably received and the lengths of testing pile can be up to 70 m. （2） This paper has proposed the calculate methods of wave velocity, relative amplitude attenuation and frequency of vertical logging. （3） The new method to judge the integrity of pile has been presented. The signal transmitted from the pile bottom can be detected in the test which includes length more than 50 m of 126 piles and the effect is good. The problem of pile integrity testing to test the long piles, which are longer than 40 m, has been solved to some extent. This method has obtained invention patent. （4）The research results have applied in the field of civil engineering.