Grouting Study Of The Under Gob Of Tai-Jia Freeway

Grouting is one of most popular engineering approaches in the Gob Management of Freeway.This paper systematically studys the entire process of the Gob grouting, including previous research results, grouting slurry diffusion mechanism, grouting material mix test, numerical simulation of the whole filling grouting gob, grouting and numerical simulation of the actual project analysis parts,process of the grouting program and so on.According to Gob geological conditions and structural characteristics, the author divide the gob to three types of geological forms area: rock slumping body deposits, coal pillars and hole zone or rock tunnel. Grouting previous theoretical studies mostly focus on the permeation grouting, so the author will use it at the first geological type above. And the theory of pillar splitting grouting was applied for the study of the second type, then the corresponding characteristics of the slurry diffusion law were drew out. In empty areas or rock space, the slurry is flowing from laminar flow to turbulence process. Finally, all the mined out space will be filled, which meets the purpose of grouting.The author had participated in the gob grouting project of Shanxi Tai-Jia freeway. From that, the field trial was done by studying the size changes of compressive strength of the cement-fly ash slurry stone at the different ratio with changeable ages, and the curve was got at last in two kinds of external environment ----nder the water or not; At the same time, comparative analysis of compressive strength of slurry stone at different solidity ratio and different water-solid ratio in the nature conditions was shown by curves. So an optimum slurry mix in regions was given with the recommended values.In this paper, the author built a gob ideal model, used Finite-element Numerical Simulation software---- Ansys, step by step simulated the grouting process from the mined area affected only by the weight eventually to filling the whole gob. The results showed that the reserved coal pillars had a great impact for the deformation of coal mined areas, while the upper subgrade uniformly distributed static load has little effect overall settlement deformation. On this basis, two-dimensional geological model about the Tai-Jia freeway gob was built, and simulated by Ansys. Results showed that, after filling by grouting all the deformation of the Gob significantly reduced, or even close to zero, which told us grouting effect was obvious. So we can get an obtained reasonable, feasible and effective conclusion about the grouting.Based on the above theoretical analysis and experimental findings, taking the actually grouting project for example, this paper analyzed and described the entire grouting process, including grouting techniques, grouting parameters, grouting test and so on, and the corresponding conclusions were obtained. Finally, the theoretical analysis, experimental research and practice formed a complete system for grouting gob, which had some theoretical and practical guidance value for managing mined out space in the future.