A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure...A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure. The results show that the water absorbing capacity of rock with a certain pressure is larger than that of rock without pressure： however, the relationship between the water absorbing percentage and the time can be expressed by w（t） = a（l - e^-bt）. In hi-logarithmic coordinates, the hydrophilic relationship with time in tests with pressure could be characterized by linearity, while they present concave or convex in tests without pressure. Based on the hypothesis that each influential factor is irrelevant and they have a linear correlation with the water absorbing capacity, we calculated the weight coefficient of each factor according to experimental results under different conditions. The calculations demonstrate that the effec- tive porosity, content of smectite and kaolinite are all positively correlated with the water absorption capacity of rock; meanwhile, the fractal dimension of the effective pores presents a negative correlation with the water absorption capacity of rock. The water absorption capacity with pressure increases with increasing illite, chlorite and chlorite/smectite formation and a decrease in illite/smectite formation and the fractal dimension of the effective pores, while it is opposite in tests without pressure. The weight coefficient of smectite is smallest among positive factors, and the fractal dimension of the effective pores is the smallest amongst the negative factors.展开更多
In order to understand the change rules of stress-displacement in surrounding rocks of dynamic pressure roadways in deep mines and to obtain a theoretical basis for analyses of roadway stability and designs of support...In order to understand the change rules of stress-displacement in surrounding rocks of dynamic pressure roadways in deep mines and to obtain a theoretical basis for analyses of roadway stability and designs of support, we established a coupling equation of adjacent rock strength, mining stress and supporting resistance on the basis of an elastic-plastic theory of mechanics. We obtained an analytical solution for stress and displacement distribution of elastic and plastic regions in surrounding rock of dy-namic pressure roadway.. Based on this theory, we have analyzed the changes in stress-displacement in elastic and plastic regions of surrounding rocks of dynamic pressure roadways in the Haizi Coal Mine. The results show that: 1) radial and tangential stress change violently within the first 4 m from the inner surface of a roadway after excavation; radial stress increases while tangential stress decreases within a range of about 6 m from the inner surface of the roadway as a function of q3; 2) radial and tangential stress increase with an increase in the mining pressure coefficient k; the increase in the rate of tangential stress is greater than that of ra-dial stress; 3) the radial displacement of the inner surface of roadways decreases with an increase in q3, provided that k remains unchanged.展开更多
Based on a large amount of field investigation and observations, the paper analyzes and summarizes the mining depths and depth distribution of coal mines in China, discusses the characteristics of undrground pressure ...Based on a large amount of field investigation and observations, the paper analyzes and summarizes the mining depths and depth distribution of coal mines in China, discusses the characteristics of undrground pressure appearance in the entries of deep mining, points out some characteristics of surtounding rocks when rHo> =0.5, such as obvious rheologital deformation,and puts forward the main principles of supporting the entries in deep mining展开更多
文摘A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure. The results show that the water absorbing capacity of rock with a certain pressure is larger than that of rock without pressure： however, the relationship between the water absorbing percentage and the time can be expressed by w（t） = a（l - e^-bt）. In hi-logarithmic coordinates, the hydrophilic relationship with time in tests with pressure could be characterized by linearity, while they present concave or convex in tests without pressure. Based on the hypothesis that each influential factor is irrelevant and they have a linear correlation with the water absorbing capacity, we calculated the weight coefficient of each factor according to experimental results under different conditions. The calculations demonstrate that the effec- tive porosity, content of smectite and kaolinite are all positively correlated with the water absorption capacity of rock; meanwhile, the fractal dimension of the effective pores presents a negative correlation with the water absorption capacity of rock. The water absorption capacity with pressure increases with increasing illite, chlorite and chlorite/smectite formation and a decrease in illite/smectite formation and the fractal dimension of the effective pores, while it is opposite in tests without pressure. The weight coefficient of smectite is smallest among positive factors, and the fractal dimension of the effective pores is the smallest amongst the negative factors.
基金supported by the National Natural Science Foundation of China (No50874103)the National Basic Research Program of China (No2006 CB202210)the Natural Science Foundation of Jiangsu Province (NoKB2008135)
文摘In order to understand the change rules of stress-displacement in surrounding rocks of dynamic pressure roadways in deep mines and to obtain a theoretical basis for analyses of roadway stability and designs of support, we established a coupling equation of adjacent rock strength, mining stress and supporting resistance on the basis of an elastic-plastic theory of mechanics. We obtained an analytical solution for stress and displacement distribution of elastic and plastic regions in surrounding rock of dy-namic pressure roadway.. Based on this theory, we have analyzed the changes in stress-displacement in elastic and plastic regions of surrounding rocks of dynamic pressure roadways in the Haizi Coal Mine. The results show that: 1) radial and tangential stress change violently within the first 4 m from the inner surface of a roadway after excavation; radial stress increases while tangential stress decreases within a range of about 6 m from the inner surface of the roadway as a function of q3; 2) radial and tangential stress increase with an increase in the mining pressure coefficient k; the increase in the rate of tangential stress is greater than that of ra-dial stress; 3) the radial displacement of the inner surface of roadways decreases with an increase in q3, provided that k remains unchanged.
文摘Based on a large amount of field investigation and observations, the paper analyzes and summarizes the mining depths and depth distribution of coal mines in China, discusses the characteristics of undrground pressure appearance in the entries of deep mining, points out some characteristics of surtounding rocks when rHo> =0.5, such as obvious rheologital deformation,and puts forward the main principles of supporting the entries in deep mining
