Research on temperature effect of consolidation and bearing capacity of multi-source coal-based solid waste backfill

In order to study the consolidation bearing capacity of coal-based solid waste paste backfill in deep high ground temperature environment of coal mine, uniaxial compression and acoustic emission tests were used to test the strength and failure characteristics of paste backfill under different curing temperature conditions (20 ℃, 35 ℃ and 50 ℃) and ages (3 d, 7 d, 14 d and 28 d). The microstructure and mineral composition of the filling cement were measured by SEM, and the influence of curing temperature on the hydration reaction was revealed from the microscopic point of view. The results show that: with the increase of curing temperature, its influence on hydration reaction gradually changes from promotion to inhibition, and the 28 d compressive strength reaches the maximum at 35 ℃; acoustic emission events mainly occur in the compaction and failure stages. The increase of curing temperature promotes the activity of acoustic emission in advance, and the failure mode of filling body gradually changes from ductile failure to brittle failure; due to the thermal damage, high temperature curing accelerates the early hydration reaction rate of the filling body, and causes damage to the C-S-H and pore structure of the filling body in the later stage of curing, which has an adverse effect on the increase of its long-term strength.