Proceedings - Fourth International Conference - Theory and Practice of Piling and Deep Foundations in China, 1991, Beijing, China, (DFI)
Research on Dynamic Inspection of Prototype Models of Reinforced Concrete Piles
Xuhui Lu Yaosheng (Academy of Railway Sciences, Beijing, China) Jiao Yusen
Pile foundations are underground projects which are carried out under complicated site conditions, so it is difficult to summarize their characteristic patterns from the ever-changing practical pile foundations. In combination with theories, the paper analyses the effect of sound reinforced concrete piles and various types of defective piles on the propagations of stress waves. Through testing on prototype pile models, by use of the transient dynamic method and comprehensive analysis in both time domain and frequency domain, their reflection characteristics and patterns are acquired. In addition, discussions are carried out in combination with some real projects. Our model tests include comparison of large scale pile models of 20 x 20cm in cross section, 5.0m in length respectively in air, standard sand, and natural stratum; Prototype model tests of bored piles of 0.6m, 0.8m in diameter, 12-20m in length. Test results show that no matter in air or buried in medium, the intrinsic characteristics of sound piles and various types of defective piles are fixed. In their time domain waveforms and spectral diagrams, obvious regularity are shown, which proves that the relations between the pile natures and their dynamic responses are fixed, which provide basis for correct judgement of pile soundness and natures of defective piles.
|article #17; publication #38 (IC-1991-CH)|