中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 24 No. 11 November 2014 |
(1School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: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.
Key words: fault areas; geostress distribution; borehole stress-relief method; lateral pressure coefficient; horizontal tectonic stress