Monitoring and Analysis of Ground Subsidence and Backfill Stress Distribution in Jinchuan Mine, China

Backfilling is widely used in mining operations. Deformation of a large volume of backfill leads to rock movement and ground subsidence. This study analysed ground subsidence and backfill deformation, combined with ground subsidence monitoring and numerical simulation. The results showed that the ground subsidence trough was located at the centre of the hanging wall of the ore body. The maximum vertical displacement exceeded 2000 mm. Underground excavation and filling led to stress redistribution. The shear stress concentrated at the backfill boundary and contact zone of the backfill and surrounding rock. The shear stress distribution changed with the shape of the backfill. The corner of the backfill boundary was the key position of shear stress concentration. The Mohr’s circle showed the envelope line where cohesion of 500 kPa could meet the strength requirement in the shallow part of the backfill; in the deep part, the cohesion required was 1500 kPa. The deep part of the backfill therefore failed more easily than the shallow part.