Equivalent elastic model of splitting grouting reinforcement in weak strata

The quantitative calculation of the grouting reinforcement effect in weak strata is a prerequisite for the scientific design of pregrouting reinforcement. Based on the diffusion mechanism of splitting grouting in weak strata and engineering practice, a typical combination structure of grout veins and soil in grouted reinforced strata is summarized and proposed. Using homogenization methods, an equivalent transversely isotropic model for the grouting reinforcement body is established.Using the principle of deformation compatibility and the constitutive equations of transverse isotropy, a calculation method for the equivalent elastic parameters of the pregrouted reinforcement body is developed. On this basis, the influence of key grouting engineering construction parameters-such as surface grouting hole layout density, grout injection rate, and the grouttosoil elastic modulus ratio-on the equivalent elastic parameters of the grouted reinforcement body is analyzed.The research results show that the layout density of surface grouting holes has a relatively small impact on the equivalent elastic modulus of the composite soil body. Increasing the grout injection rate can effectively improve the equivalent elastic modulus and equivalent Poisson's ratio of the grouted reinforcement body. Additionally, when the grouttosoil elastic modulus ratio is less than 0.2, changes in this ratio have a significant impact on the equivalent elastic parameters. As the elastic modulus ratio increases, this impact becomes less pronounced. Finally, the accuracy and effectiveness of the calculation method for the equivalent elastic parameters of the pregrouted reinforcement body are validated through an engineering case study involving the pregrouting treatment of water-rich weak strata in the Qingdao Metro Line 13.