Abstract: Under the action of corrosion, abrasion and erosion from groundwater, the cementation structure in Karstic collapse column is broken and some particles are lost. As the action continues for a certain time, the seepage burst will occur. In order to study the water inrush mechanism of Karstic collapse column, the original designed compacting device and seepage experiment system of broken rock have been used to complete the seepage experiment of cemented broken mudstone. The influence of cementing material, water pressure, broken mudstone size distribution and initial porosity on seepage characteristics has been analyzed. The results have shown that: 1) With cementing strength increasing, the duration time of seepage burst gets longer; When the cementing material is cement, the seepage capacity tends towards stability without burst. 2) With the water pressure increasing, the duration time of seepage burst gets shorter by an exponential function. 3) With the Talbol power exponent increasing, the rock particles in big sizes get more and the water-blocking ability strengthens. 4) With initial porosity increasing, the seepage capacity strengthens. The duration time of seepage burst gets shorter through an exponential function.

Key words: Karstic collapse column, cemented, broken mudstone, seepage characteristics, seepage burst