堤基管涌微观机理模型试验研究

本文从微观角度出发,开展小尺寸模型试验,采用显微镜和数码成像系统对管涌土体进行局部放大摄录,通过常规观察试验现象和数字图像识别分析不同水头下管涌土体颗粒级配,分析了管涌发展过程中随水头变化的土体颗粒位移和流失规律,从宏观和微观角度共同阐释了管涌发生、发展的机理。试验结果表明,堤基管涌发生、发展的微观颗粒流失过程与宏观现象一致,管涌发生、发展的过程从微观角度即表现为颗粒位移并流失的过程。通过微观颗粒位移与宏观管涌通道发展相结合分析,更深层次剖析了管涌发展的机理。本研究对于管涌数学模型和数值模型的建立、提高管涌防治技术水平等具有参考意义。

Experimental study on the microcosmic mechanism of backward piping in dike foundations

Small scale experiments are conducted to try to explain the microcosmic mechanism of frequent backward piping in dike foundations during flood seasons. The sand matrix is photographed and recorded by zooming in video using the microscope and digital imaging analysis system during the experiments. By combining common visual observation of the phenomenon with analysis of the particle grading during different water head by digital image acquisition system, the particle displacement and loss pattern along with the water head increasing are analyzed. The mechanism of backward piping is explained both from macro- scopic and microcosmic view. The experiments show that the particle displacement and loss process are consistent with the observed phenomenon. The process of backward piping just refeects the particle displacement and loss process. Based on the integrated analysis on the particle displacement and piping channel progress, the backward piping mechanism is explored more deeply. This research will trigger the inspiration for establishing both mathematical and numerical models, and is also useful for improving the technology of countermeasures against backward piping.