Stress-Strain State of the Zagorskaya PSHPP-2 Foundation During Compensation Grouting

The stress-strain state (SSS) of a foundation in the case of targeted grout injection using the compensation grouting (CG) method is numerically modeled using the example of lifting the Zagorskaya PSHPP-2 foundation slab. The elastoplastic formulation according to the model of Prof. L. N. Rasskazov and the Coulomb – Mohr strength condition were applied for considering the foundation SSS at the beginning and in the course of the grouting process, respectively. Modeling is performed by the finite element method (FEM) in a spatial setting when the area is divided into four-node elements comprising tetrahedra with linearly approximated displacements between nodes. The effect of the CG technological parameters on the lift value for the bottom of the hydraulic structure foundation slab is investigated. The main CG parameters include the volume of the grout injected into the one collar, the depth of the collar location in the soil base, the number of collars in one vertical, and the number of collars on the sides of the foundation slab. The calculated values of the studied parameters were obtained based on the values of the actual settlement of the structure contacting with the soil base. In this case, the location of collars was obtained based on the minimum injected volume required to compensate for the settlement of the structure. According to the numerically modeled lift of the Zagorskaya PSHPP-2 foundation slab by the method of compensation grouting, recommendations were given for the process parameters including the required volume of the injected grout (grouting volume), which amounted to about 9240 m3, the number of collar pipes distributed over the settled base area (74 pcs), and the plan view of the collar pipe layout. © 2022, Springer Science+Business Media, LLC, part of Springer Nature.