Monitoring and Analysis of Stress and Deformation Features of Boundary Part of Backfill in Metal Mine

Abstract

The backfill mining method is widely used in metal mines. A large and thick backfill body has formed in the No.2 zone of Jinchuan Nickel Mine, and its stability is critical for mining safety. In order to study the mechanical behavior of the boundary part of backfill, ground subsidence monitoring, underground filed monitoring of displacement, and stress and numerical simulation were conducted to analyze stress distribution and deformation of backfill. According to underground monitoring, the bed separated displacement has the consistent trend with ground subsidence in the mine area. Based underground stress monitoring, both horizontal and vertical stress of the internal part of backfill is less than the stress boundary part of the backfill. The characteristic of backfill boundary outline is a step-profile. Contact interaction between the surrounding rock and backfill led to complex stress distribution. According to stress monitoring of the boundary points in a numerical model, the multi-peak value of stress development is the major feature of the boundary part of backfill. The multi-peak stress behavior of the boundary part of backfill was influenced by mining depth. The boundary part of backfill deformation influenced the local stability of mining. This article provided a scientific basis for strength design and the support choice of a metal mine by the method of backfill mining.