Study on the mechanics and permeability characteristics of cemented backfill with different mineral admixtures

Using the solid waste of metal mines to build underground oil storage in its goaf can not only reduce the accumulation of solid waste in the mining area and protect the environment, but also rationally use the goaf and realise the development and utilisation of underground space. Because the mechanical properties and permeability of filling materials are very important to the safety and stability of the storage, this paper aims at the differential temperature filling work in different buried depth mines. In order to grasp the influence of underground temperature on the mechanical properties and permeability of filling body, this paper sets four groups of curing temperatures of 20 similar to 50 degrees C to carry out differential temperature curing of filling bodies with different mineral admixtures, and carries out relevant tests on filling body samples under each group of curing temperatures. The results show that : (1) When the curing temperature increases from 30 degrees C to 50 degrees C, the uniaxial compressive strength of the filling body with different mineral admixtures increases first and then decreases. (2) Increasing the curing temperature can reduce the porosity and pore size of the backfill containing mineral admixtures, and also increase its tortuosity, thus reducing the permeability of the backfill containing mineral admixtures; (3) Through the linear fitting of the permeability and pore structure parameters of the backfill containing mineral admixtures, it is found that the permeability is proportional to the porosity and pore size, and the tortuosity is inversely proportional.