Abstract
The instability of extraction structure under the undercut space in the block caving stope presents specific characteristics: rib spalling and floor heave in ore-loading roadway and collapse of major apexes. In order to study the stress and displacement evolution law of extraction structure under undercut space and reveal the instability mechanism of extraction structure, the numerical simulation model of block caving stope was established using the finite difference software FLAC3D. According to the postundercutting strategy in Tongkuangyu Mine in China, extraction structure was formed first in the simulation process, and then the undercut level was divided into eight units for excavation step by step. The stress and displacement of extraction structure after each step of undercutting were monitored and analyzed. Based on the thin plate theory, the mechanism of stress change and deflection deformation of extraction structure was revealed. The research results show that, under the action of high horizontal tectonic stress and vertical stress, the extraction structure under undercut space produces vertical upward bending deformation after undercutting during the block caving. The tension stress concentration gradually appears in the side wall of the ore-loading roadway and the tip of the major apexes; with the increase of the undercutting area, the degree of tensile stress concentration gradually becomes strong; when the tensile strength of the rock mass in extraction structure is exceeded, extraction structure presents instability. It is necessary to make the overlying ore collapse on extraction structure as soon as possible after undercutting, which is beneficial to release the tension stress in the extraction structure under undercutting space.
Highlights
As a large-scale, low-cost, and high-efficiency underground mining method, block caving mining method is the preferred method for deep ore resources when conditions permit [1,2,3]. e extraction structure of block caving mining method refers to a series of roadways and excavations between the undercut level and the production level [4, 5]. e extraction structure undertakes the task of ore drawing, and all ores need to be transported out of the stope through the extraction structure. erefore, ensuring the safety and stability of the extraction structure is one of the key factors for the successful application of the block caving method
Xia et al [11, 12] studied the instability mechanism of the extraction structure under the conditions of multiple production levels in one panel and poor undercutting in block caving method by using three-dimensional numerical simulation method. e research on the force of ore bulk on the extraction structure under the undercut space has gradually attracted the attention of mining scholars
Castro et al [16, 17] studied the variation of vertical stress of extraction structure in stope under three kinds of ore drawing conditions by using laboratory physical model; the research shows that the vertical stress was mainly affected by the area of ore drawing area and the distance from the ore drawing advancing front
Summary
Received 3 February 2021; Revised 16 February 2021; Accepted 22 February 2021; Published 28 February 2021. E instability of extraction structure under the undercut space in the block caving stope presents specific characteristics: rib spalling and floor heave in ore-loading roadway and collapse of major apexes. In order to study the stress and displacement evolution law of extraction structure under undercut space and reveal the instability mechanism of extraction structure, the numerical simulation model of block caving stope was established using the finite difference software FLAC3D. E tension stress concentration gradually appears in the side wall of the ore-loading roadway and the tip of the major apexes; with the increase of the undercutting area, the degree of tensile stress concentration gradually becomes strong; when the tensile strength of the rock mass in extraction structure is exceeded, extraction structure presents instability. It is necessary to make the overlying ore collapse on extraction structure as soon as possible after undercutting, which is beneficial to release the tension stress in the extraction structure under undercutting space
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
