Abstract: Due to the concealment of grouting engineering and the nature of geological structures, the diffusion mechanism of splitting compaction grouting is very complex, and the evaluation of grouting reinforcement effect is not yet deeply understood. This article considers the morphology of grouting veins and the structural characteristics of sand layers, and constructs a calculation model of grouting plus solid mechanics. Based on the basic principles of soil mechanics and elastic mechanics, quantitative analysis and calculation of the grouting reinforcement effect are conducted. By selecting characteristic unit volumes, the spatial anisotropy characteristics of sand compression modulus, shear strength, and anti-seepage performance were studied. Finally, the scientific and applicability of the calculation method was verified through the sand layer grouting reinforcement project of Zhengzhou Metro Line 12. Results show that sand and solid φ_s and φ_c is basically consistent, while c_s and c_c have significant differences due to different shear failure mechanisms, with c_s much smaller than c_c. There are also differences in the seepage mechanism between the vertical and parallel directions of the plasma veins, with k_c being 4~5 orders of magnitude smaller than k_s. The anti deformation performance in the parallel plasma direction is slightly higher than that in the vertical direction. The research results of this article can effectively improve the theoretical design level of split grouting and provide scientific guidance for the construction of sandy soil engineering projects.