In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using enginee...In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using engineering geological mapping of 1961 meters of the scanline, experiments on intact rock samples and measuring P-wave velocity(Vp) for 1771 meters of seismic profiles. The results indicate that increasing spacing, persistence, opening, roughness, waviness of discontinuities, and Vp and uniaxial compressive strength(UCS) of intact rock as well as the increase of discontinuities angle with the bench face of blasting block will increase the size distribution of blasted rocks. In addition, evaluation of the influence of connector type, specific drilling and specific charge has shown that using the Nonel system will decrease the mean size of fragmentation. It is also demonstrated that increasing specific drilling and specific charge quantities will result in the increase of mean size of fragmentation.展开更多
A stratified rock mass model was founded by FLAC3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visua...A stratified rock mass model was founded by FLAC3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visually reflect the failure modes of rock samples under different inclination angles β of structural plane. The stiffness of rock sample before peak strength changes in the compressive procedure. With the increase of β, the compressive strength σc of rock sample decreases firstly and then increases; when β is in the range of 20°-30° and 80°-90°, σc has the largest sensitivity to β; while β falls in the range of 30°-70°, σc varies little. When φ j<β<90°. (φj is friction angle of structure plane), the results obtained from numerical simulation and theoretical analysis are in almost the same values; while β≤φ j or β=90°, they are in great different values. The results obtained from theoretical analysis are obvious larger than those from numerical simulation; and the results from numerical simulation can reflect the difference of compressive strength of rock samples for the two situations of β≥φj and β=90°, which is in more accordance with the real situation.展开更多
文摘In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using engineering geological mapping of 1961 meters of the scanline, experiments on intact rock samples and measuring P-wave velocity(Vp) for 1771 meters of seismic profiles. The results indicate that increasing spacing, persistence, opening, roughness, waviness of discontinuities, and Vp and uniaxial compressive strength(UCS) of intact rock as well as the increase of discontinuities angle with the bench face of blasting block will increase the size distribution of blasted rocks. In addition, evaluation of the influence of connector type, specific drilling and specific charge has shown that using the Nonel system will decrease the mean size of fragmentation. It is also demonstrated that increasing specific drilling and specific charge quantities will result in the increase of mean size of fragmentation.
基金Project (50099620) supported by the National Natural Science Foundation of China
文摘A stratified rock mass model was founded by FLAC3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visually reflect the failure modes of rock samples under different inclination angles β of structural plane. The stiffness of rock sample before peak strength changes in the compressive procedure. With the increase of β, the compressive strength σc of rock sample decreases firstly and then increases; when β is in the range of 20°-30° and 80°-90°, σc has the largest sensitivity to β; while β falls in the range of 30°-70°, σc varies little. When φ j<β<90°. (φj is friction angle of structure plane), the results obtained from numerical simulation and theoretical analysis are in almost the same values; while β≤φ j or β=90°, they are in great different values. The results obtained from theoretical analysis are obvious larger than those from numerical simulation; and the results from numerical simulation can reflect the difference of compressive strength of rock samples for the two situations of β≥φj and β=90°, which is in more accordance with the real situation.
