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The grouting method is often used to strengthen the bearing capacity of building foundations. In the process of grouting, the stress structure of slurry and rock and the soil mass under the condition of high permeability and high stress (“double height”) is complex, and the strength mechanism of slurry stone under different double-height conditions is not clear. Therefore, stone samples of grout under the curing pressures of 2 MPa, 4 MPa, 6 MPa, 8 MPa and 10 MPa were prepared for the uniaxial compression test to analyze the influence of curing pressure on compressive strength. The microstructure of the slurry stone was observed by scanning electron microscope, and the development law of microcracks was further studied using the particle flow program. The research shows that the strength of the slurry stone body increases with the increase of curing pressure. When the curing pressure increases from 2 MPa to 10 MPa, the compressive strength of the stone powder-cement slurry stone body increases from 8.3 MPa to 22.7 MPa, an increase of nearly 2.7 times, and the compressive strength of the clay-cement slurry stone body increases from 5.7 MPa to 16.8 MPa, an increase of 2.9 times. According to the axial compressive stress-strain curve of the specimen, the failure process goes through three continuous stages: continuous elasticity, crack propagation, and strength failure. When the stress peak is reached, the number of cracks increases slowly; when the stress peak is reached, the cracks expand rapidly, the number increases exponentially, and a penetrating main crack is finally formed, which destroys the specimen. This study provides a reliable basis for the selection of grouting parameters and grouting materials in stratum-grouting engineering.

Clay cement grout is frequently employed in geotechnical reinforcement projects. However, laboratory test revealed that clay cement slurry does not consolidate in a closed environment for an extended period of time, with cracks forming during the consolidation process under natural conditions, indicating that the geotechnical reinforcement poses dangers. Stone powder is a powdery solid waste similar to clay materials. Stone powder particle surfaces provide an attachment point for cement reaction, which can speed up cement hydration, with the ability to substitute clay cement slurry. According to our findings, the bleeding rate of clay cement slurry is 14.80% at 290 mm fluidity, and that of the same mass ratio (1:3) as stone powder cement slurry is 11.09%. The bleeding rate is minimal, which promotes the creation of an integral structure after setting between the slurry and lose rock and soil. Mechanical test results show that the strength of the stone powder cement slurry hardened body is 1458 kPa, whereas the strength of the clay cement slurry hardened body is 436 kPa. Microstructural analysis shows that the stone powder cement hardened body has more hydration products and is porous than the clay cement hardened body. The hardened body of stone powder cement slurry has high strength and resistance to external loads, which can increase the bearing capacity and improve the geotechnical reinforcement effect.