Abstract: In order to study the erosion effect of in-situ leaching mother liquor on the receiving floor of ionic rare earth ore, an indoor leaching simulation test was carried out with the bedrock of ionic rare earth ore (semi/weakly weathered granite) as the research object. The stress-strain curves, peak stress, peak strain and elastic modulus of rock samples for different leaching durations are compared and analysed, the porosity and micro morphology characteristics of rock samples for different leaching durations are obtained, and the nonlinear crack characteristics of rock samples are described quantitatively by box dimension method. The results show that the effect of leaching erosion on the mechanical properties of the bedrock of the floor of ionic rare earth ore is mainly manifested in the first 150 days, and the failure form changes from penetration failure to the coexistence of penetration failure and flaky spalling. Under the erosion of ore leaching mother liquor, the mechanical properties of bedrock first decrease greatly and then rise sharply, and then fluctuate in a small range. About 60 days of ore leaching has the greatest impact on the mechanical properties of bedrock. The erosion of ore leaching mother liquor causes the growth of small pores in the bedrock, resulting in corrosion and holes on the surface. Different leaching durations will cause different microstructure changes of rocks.

Key words: ionic rare earth, leaching erosion, floor bedrock, mechanical properties, microstructure