## 1 Introduction
the mechanical properties of the whole rock mass to effectively prevent the instability and failure of underground engineering. At present, researchers have carried out many mechanical studies on the strength and deformation characteristics of the consolidated body after grouting. Through a series of grouting tests, [PERSON] et al. [26] and [PERSON] et al. [27] found that the shear strength curve of grouting consolidation has an obvious peak and residual strength. [PERSON] et al. [28] used chemical grout to grout fractured rock masses and found that this method can make the specimens a more complete structure. However, the strength of the grouting material and its bonding with the rock mass are important factors limiting the grouting results. Based on the study of residual strength and deformation properties of fractured rock, [PERSON] et al. [29] further explored the mechanical properties of grout-reinforced specimens. The research shows that after grouting consolidation, the residual strength of the broken rock block is significantly improved, and its lateral and radial changes also tend to be synergistic, which greatly improves the plastic deformation function of the broken rock block so that it can still maintain good bearing capacity in a large change range. At present, many researchers have conducted much research on rock-like specimens instead of rock as rock mechanics test materials. However, there are relatively few studies on the mechanical properties of grout-reinforced specimens prepared by real rock mass cutting and grouting. [PERSON] [30], [PERSON] [31], and [PERSON] [32] all took gypsum as the analysis object and analyzed the effect of fracture dip angle on rock hardness and deformation characteristics. [PERSON] et al. [33] studied the law of damage and deterioration of rock with a filling joint caused by the acid dry-wet cycle and found that there was a strong linear relationship between the static and dynamic compressive strength and the wave velocity of the filled joint rock under the action of dry and wet cycling. [PERSON] et al. [34] studied the evolution of microscopic pores and the shear mechanical response of fractured rock under freeze-thaw cycles and found that the freeze-thaw deterioration of the grout rock interface layer was mainly caused by the solid-liquid phase change and migration of internal water under the action of circulating temperature, and the difference of grouting materials had a great influence on the degree of freeze-thaw deterioration of the grout rock interface layer. For the study of the physical and mechanical properties of grout-reinforced specimens, most are only based on the study of grout-reinforced specimens mechanics and grouting effect under a normal temperature environment. Some scholars have studied the damage of grout-reinforced specimens under low-temperature or single acid-base environment. There are few studies on the mechanical damage of grout-reinforced specimens under the coupling of an acid environment and a freeze-thaw cycle. In this paper, combined with the research status of grouting materials and grout-reinforced specimens and considering the existing conditions, the uniaxial compression test and scanning electron microscope microscopic imaging method were used to carry out the test of the grout-reinforced specimens erosion in an acidic environment and the test of grout-reinforced specimens performance damage under the coupling of a freeze-thaw cycle in an acidic environment.