River mining overburden failure under the laws of physics simulation
And appear in the lower part of the macro-crack. When face to continue moving forward, the roof is always in the open cut in the side caused by the excavation of the tensile stress the role of roof rock beam maximum stress region continues to move forward, the maximum damage zone has also been moved forward to form asymmetrical roof breaking. This process of breaking the old roof, with the ongoing and repeated excavation and roof damage is mainly caused by tensile stress. 2.3 Surface movement law of surface rock move the stable, the level of observation by the first line of the measuring points (measuring points 1 to 21) to form the final sinking value of the curve that reflects the law of ground movement (shown in Figure 3 ). Subsidence curve shape was asymmetric (skewed ######). Rock sinking curve skewed, and is the rock from the roof of the breaking of the skewed due. The largest amount of subsidence model 11.32mm, the actual performance of the maximum surface subsidence is 1.132m. China Mining 17 54 0 Viola 26. . 812 measuring points 12345678910l112131415161718192021 2.4 3 subsidence curves move within the law of the surface rock stable rock movement, observed by the middle vertical line of the sinking value of the final observation point, calculate the different heights of rock subsidence coefficient, get the vertical movement of the model curve and the sinking factor deformation and rock mining height and thickness than the relationship. Measured and calculated data in Table 2. According to the data in Table 2, the points can be drawn out of the sinking factor y 2 values at different depths of the rock sinking and sinking coefficient measuring point number measuring point roof height (m) height and thickness than the measurement points taken under the final sink value (m) subsidence coefficient l3.8l3O. 9240.7449.8458.8668.3477.6587.13ll1.65 seam roof with the pitch height of H and M Coal Seam thickness ratio diagram (Figure 4), can be obtained by curve fitting between the two relationship between the function: Y a 1.134 a O. O134X where y a different depth strata subsidence coefficient; x a rock from the coal seam roof height H and M Coal Seam thickness ratio, ie H / M. It is shown that different depths of the rock sinking coefficient with depth and rock mining thicker than a linear relationship with the rock from the coal seam roof height increases, the subsidence coefficient decreases. Figure 4 subsidence coefficient with rock rock and coal mining height to thickness ratio of diagram 3 Conclusions similar material simulation method to study the river to move overburden mining disturbance laws of deformation and failure, the following conclusions: (1) face after mining , mined-out area around the rock has undergone a more complex movement and deformation, direct from the coal seam roof began to take place off the bottom turn, fracture, separation, cracks and bending, and finally the formation of caving zone,
ugg uk, fracture zone and overall bending band. (2) is expected to L3414 fully mechanized coal face mining, the overburden of caving with a height of 1O ~ 14m; hydraulic conductivity fracture zone height of 32 ~ 46m; caving step of 7 ~ 14m; caving angle of 4O. 65. . (3) face mining, the maximum surface subsidence is 1.132m. (4) The different depths of the rock formations of subsidence coefficient and the depth / thickness ratio adopted a linear relationship with the rock from the coal seam roof height increases, the subsidence coefficient decreases. (5) face the mining process, the sinking roof strata not completely synchronized, but was non-continuous, there are cracks between each other, but with the continuous advance of the face, lower part of the rock fissures decreases or closed, the upper strata abscission layer but also the emergence of new space, and continues to the shallow development. (6) face mining, the mined-out area around the rock is moved and deformed, crack band of mostly vertical or diagonal cracks in the main. Caving rock band with a bedding of chaos,
moncler outlet, rock angle changes and other features. A References [1] Beijing University of Technology, a new coal mine in Ningxia Coal Industry Group Spirit. West Tian Ling Ningxia new coal mine safety technology research under the JR]. 2004. [2] Renfen Hua, Mei-Feng Cai, to Xingping, et al. Gob height of overburden failure monitoring and analysis of Eli. Beijing University of Technology, 2004,26 (2): 115 a ll7. [3] Mei-Feng Cai,
moncler outlet milano, Ren Fenhua to Xingping, et al. West Tian Ling, under the new coal mining technology, comprehensive safety analysis of Eli. Beijing University of Technology, 2004,26 (6) :572-574. [4] Mei-Feng Cai, to Xingping, Ren Fenhua. West Tian mined-out area under the large-scale regular field monitoring overburden fracture study [A]. Eighth National Congress of Rock Mechanics and Engineering Conference Proceedings Ec]. 2004:843-846. [5] Kang Jianrong,
moncler torino, Wang Zhuang. Jingwei observed similar material simulations to analyze Eli. Mine surveying, l998, (2) :23-26.
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