STABILITY OF MINING SLOPE USING PRINCIPLE OF COMBINING WEDGE BLOCKS

The underground mining can usually cause the surface crack and even geological disasters such as collapse and landslide. Stability of mining slope has been the practical concern. This paper takes the Meidongpo slope of underground mining as an example. It is in Duyun city of Guizhou province. The paper formulates a stability calculation equation of mining slope on combined wedge block principle. The formulation is based on slope failure mechanism analysis. The calculation of slope safety factor is carried out under the natural, water-saturated and fissure water filling situation. The comprehensive value of strength parameters is based on experiment, and analogy experience method, and mining empty rate. These results show that the Meidongpo mining slope is usually in a stable state, but its stability becomes worse in long-time rainfall or rainstorm condition, and even unstable. The safety factor of Meidongpo slope decreases as the internal friction angle decreases and the height of fissure water filling increases. Once the back block extrudes front block, there can be a threshold that the safety factor decreases sharply. It formulates a formula of depth of fracture water with rainfall from the relationship between depth of fracture water and rainfall infiltration of crack. It finds that the slope can fail when the rainfall exceeds more than 192mm in a very short time.