To minimize negative effects of geostress distribution on mining safety near the fault areas, the UPM40 triaxial geostress testing system was introduced to conduct in-situ geostress measurements at three sites and nin...To minimize negative effects of geostress distribution on mining safety near the fault areas, the UPM40 triaxial geostress testing system was introduced to conduct in-situ geostress measurements at three sites and nine points by the borehole stress-relief method. The results of strain?confining pressure curves show that rock masses at the three measuring sites exhibit comprehensive linear elasticity in spite of various fissures or cracks within rocks. Horizontal and vertical stress components distribute discrepantly near the fault areas, and the maximum lateral pressure coefficient is as high as 6.15. The maximum principle stress ranges from 8.01 to 14.93 MPa, and stress directions are in the range of N78.07°W?N17.55°W. Geostresses near fault areas are dominated by the horizontal tectonic stresses, while the lower values, compared to those under similar geological conditions are due to stress release by the fault. Additionally, the fault and shear stress nearby are partially responsible for asymmetric elongation and southwesterly migration of orebodies.展开更多
Mathematical models of tire-lateral mad adhesion for use in mad vehicle dynamics studies are set up to express the relations of adhesion coefficients with slip ratio in lateral direction.The models of tire-lateral mad...Mathematical models of tire-lateral mad adhesion for use in mad vehicle dynamics studies are set up to express the relations of adhesion coefficients with slip ratio in lateral direction.The models of tire-lateral mad adhesion revolutionize the Pacejka's model in concept and therefore make it possible for applications in vehicle dynamics studies by the expression of lateral adhesion coefficient as a function of wheel slip ratio,instead of the wheel slip angle,taking into account in the mean time the influences of mad surface condition, vehicle velocity,vertical load,tire slip angle,and wheel camber angle.展开更多
To investigate the progressive fracture processes around a tunnel triggered by static stress and dynamic disturbance,experiments and numerical simulations were performed.The results show that the spatial distributions...To investigate the progressive fracture processes around a tunnel triggered by static stress and dynamic disturbance,experiments and numerical simulations were performed.The results show that the spatial distributions of acoustic emission(AE)events become very different as lateral pressure coefficients change.The combined effect of static stress and dynamic disturbance causes the damage around the tunnel,and initial stress conditions control the damage morphology.The blast disturbance cannot fundamentally change the damaged area but will deepen the extent of damage and accelerate the failure speed.The more significant the difference between the vertical and horizontal stresses is,the higher the impact on the tunnel by the dynamic disturbance is.The AE activity recovers to a relatively stable state within a short time after the blast and conforms to power-law characteristics.展开更多
In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop metho...In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop method was employed. The sliding body was divided into strips in a three-dimensional model, and the lateral earth pressure was put into mechanical analysis and the three-dimensional stability analysis methods applicable for circular sliding in concave slope were deduced. Based on geometric structure and the geological parameters of a concave slope, the influence rule of curvature radius and the top and bottom arch height on the concave slope stability were analyzed. The results show that the stability coefficient decreases after growth, first in the transition stage of slope shape from flat to concave, and it has been confirmed that there is a best size to make the slope stability factor reach a maximum. By contrast with average slope, the stability of a concave slope features a smaller range of ascension with slope height increase, which indicates that the enhancing effect of a concave slope is apparent only with lower slope heights.展开更多
基金Projects(50934002,51104011)supported by the National Natural Science Foundation of ChinaProject(2012BAB08B02)supported by the National Key Technologies R&D Program during the 12th Five-year Plan of China
文摘To minimize negative effects of geostress distribution on mining safety near the fault areas, the UPM40 triaxial geostress testing system was introduced to conduct in-situ geostress measurements at three sites and nine points by the borehole stress-relief method. The results of strain?confining pressure curves show that rock masses at the three measuring sites exhibit comprehensive linear elasticity in spite of various fissures or cracks within rocks. Horizontal and vertical stress components distribute discrepantly near the fault areas, and the maximum lateral pressure coefficient is as high as 6.15. The maximum principle stress ranges from 8.01 to 14.93 MPa, and stress directions are in the range of N78.07°W?N17.55°W. Geostresses near fault areas are dominated by the horizontal tectonic stresses, while the lower values, compared to those under similar geological conditions are due to stress release by the fault. Additionally, the fault and shear stress nearby are partially responsible for asymmetric elongation and southwesterly migration of orebodies.
文摘Mathematical models of tire-lateral mad adhesion for use in mad vehicle dynamics studies are set up to express the relations of adhesion coefficients with slip ratio in lateral direction.The models of tire-lateral mad adhesion revolutionize the Pacejka's model in concept and therefore make it possible for applications in vehicle dynamics studies by the expression of lateral adhesion coefficient as a function of wheel slip ratio,instead of the wheel slip angle,taking into account in the mean time the influences of mad surface condition, vehicle velocity,vertical load,tire slip angle,and wheel camber angle.
基金Project(2017YFC0602904)supported by the National Key Research and Development Program of ChinaProject(51974059)supported by the National Natural Science Foundation of ChinaProject(N180115010)supported by the Fundamental Research Funds for the Central Universities,China。
文摘To investigate the progressive fracture processes around a tunnel triggered by static stress and dynamic disturbance,experiments and numerical simulations were performed.The results show that the spatial distributions of acoustic emission(AE)events become very different as lateral pressure coefficients change.The combined effect of static stress and dynamic disturbance causes the damage around the tunnel,and initial stress conditions control the damage morphology.The blast disturbance cannot fundamentally change the damaged area but will deepen the extent of damage and accelerate the failure speed.The more significant the difference between the vertical and horizontal stresses is,the higher the impact on the tunnel by the dynamic disturbance is.The AE activity recovers to a relatively stable state within a short time after the blast and conforms to power-law characteristics.
基金financially supported by the China Postdoctoral Science Foundation(No.2015M580491)the National Natural Science Foundation of China(No.51404262)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20140213)the National High Technology Research and Development Program of China(No.2012AA062004)
文摘In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop method was employed. The sliding body was divided into strips in a three-dimensional model, and the lateral earth pressure was put into mechanical analysis and the three-dimensional stability analysis methods applicable for circular sliding in concave slope were deduced. Based on geometric structure and the geological parameters of a concave slope, the influence rule of curvature radius and the top and bottom arch height on the concave slope stability were analyzed. The results show that the stability coefficient decreases after growth, first in the transition stage of slope shape from flat to concave, and it has been confirmed that there is a best size to make the slope stability factor reach a maximum. By contrast with average slope, the stability of a concave slope features a smaller range of ascension with slope height increase, which indicates that the enhancing effect of a concave slope is apparent only with lower slope heights.
