The crushed rocks are used as a filling material in mined丒out areas of underground mining. Compared with the man-made filling materials, the crushed rocks exhibit higher compressibility and lower stability, which may...The crushed rocks are used as a filling material in mined丒out areas of underground mining. Compared with the man-made filling materials, the crushed rocks exhibit higher compressibility and lower stability, which may result in instability of surrounding rock and surface subsidence. To study the creep compaction behavior of crushed mudstones, a series of creep tests are conducted. The investigations show that the creep compaction behavior of crushed mudstones is highly dependent on the original grain composition and axial stress applied on the samples. The samples with more large particles are easier to deform at initial loading stage for more large voids existed in the samples, and exhibit greater stability than those with smaller particles when the axial stress less than the bearing capacity of uframework structure When the axial stress is higher than 20 MPa, the influences of grain composition on deformability of crushed mudstones are weakened after the samples experience repeated compression. At lower stress level, the creep behavior prefers to occur in the samples w.h smaller particles, which is mainly caused by particles flow without significant particle breakage. As the axial stress increases, the single-sized sample with smaller particle size and the well-graded sample with larger Talbol power exponent n present more unstable under the constant stress. In addition, the filling of the residual intergranular voids by small particles formed by crushing and splitting behavior is the main cause of creep deformation. Lastly, a creep equation of crushed mudstones is obtained in this paper, which can agree with the experimental results in good.展开更多
基金This research was supported by the National Natural Science Foundation of China (Grant No. 51479195)the National Key Research and Development Plan of China (2016YFC0600901)+1 种基金the Special Fund of Basic Research and Operating of China University of Mining and Technology, Beijing (Grant No. 2009QL06)the State Scholarship Fund of China.
文摘The crushed rocks are used as a filling material in mined丒out areas of underground mining. Compared with the man-made filling materials, the crushed rocks exhibit higher compressibility and lower stability, which may result in instability of surrounding rock and surface subsidence. To study the creep compaction behavior of crushed mudstones, a series of creep tests are conducted. The investigations show that the creep compaction behavior of crushed mudstones is highly dependent on the original grain composition and axial stress applied on the samples. The samples with more large particles are easier to deform at initial loading stage for more large voids existed in the samples, and exhibit greater stability than those with smaller particles when the axial stress less than the bearing capacity of uframework structure When the axial stress is higher than 20 MPa, the influences of grain composition on deformability of crushed mudstones are weakened after the samples experience repeated compression. At lower stress level, the creep behavior prefers to occur in the samples w.h smaller particles, which is mainly caused by particles flow without significant particle breakage. As the axial stress increases, the single-sized sample with smaller particle size and the well-graded sample with larger Talbol power exponent n present more unstable under the constant stress. In addition, the filling of the residual intergranular voids by small particles formed by crushing and splitting behavior is the main cause of creep deformation. Lastly, a creep equation of crushed mudstones is obtained in this paper, which can agree with the experimental results in good.
