Abstract: In response to the defect that ordinary slurry is prone to shrinkage and affects the reinforcement effect,and only provides bonding effect on the supported rock mass,a grouting reinforcement idea of " squeezing first and then bonding" for expansive slurry is proposed. The system research conducted on three parts:the performance of expansive slurry,the mechanical properties of expansive slurry-rock mass composites,and the application test of expansive slurry. Firstly,the volume expansion rate,expansion stress development characteristics,and expansion mechanism of expansive slurry were introduced. The influence of different constraint conditions and stress on its expansion and strength properties was analyzed,and methods for improving the mechanical strength of expansive slurry and regulating the setting time were explored. Secondly,theoretical analysis,experimental research,and other methods were used to study the strength model and shear mechanics mechanism of the slurry-rock composites. Finally,numerical simulations and on-site experiments were used to explore the application effect of expansive slurry in the grouting reinforcement of steep layered rock roadway roof and mortar grouting anchor support,revealing its mechanical mechanism of grouting reinforcement. The results show that:① The expansive slurry has good volume expansion rate and expansion stress,and the maximum volume expansion rate is 36. 96%,20. 22% and 3. 89%,respectively,under different constraints. The uniaxial compressive strength of the sample is 2. 53,8. 82,13. 55 MPa,respectively. The more constraints on the development of slurry expansion,the smaller the volume expansion rate and the higher the strength. ② The shear strength of the slurry-rock mass composite by the grouting reinforcement with expansive slurry and ordinary slurry is 2. 95 MPa and 2. 26 MPa respectively,and the shear strength of the slurry-rock mass composite by the grouting reinforcement with expansive slurry is increased by 30. 53%. ③ The final displacement of steeply inclined stratified rock mass roadway roof by the grouting reinforcement with expansive slurry is lower than that of ordinary slurry. The stress on both sides of the roof is larger during expansive slurry grouting,and the stress on the roof is significantly greater than that after ordinary slurry grouting on the whole. ④ After adding a certain amount of expansive slurry,the mortar can produce 2. 03~ 8. 26 MPa radial expansion stress on the anchor, which is 59. 8% higher than the maximum pulling strength of the ordinary mortar anchor,and has a better anchoring effect. The above research shows that the expansive slurry has a good volume expansion effect,and although the volume expansion is limited in a limited space,resulting in a higher mechanical strength,which can effectively improve the overall compressive and shear strength of the supported rock mass,and has a good test effect in the stope roof with fault and the grouting anchor support. This study can provide good technical reference and theoretical support for the study and application of grouting reinforcement technology of underground geotechnical engineering. 

Key words: grouting reinforcement, expansive slurry, mechanical properties, expansion performance, slurry-rock mass composites