Abstract: With the increasing requirements of the construction standardization technology in China, the current permeability grouting treatment technique in the karst terrain cannot meet the construction requirements due to its construction procedure and large grouting material loss. The research scopes of this study are the following: to improve the grouting slurry-water ratio to be applied in the highway subgrade in the karst terrain, and to determine the improved permeability grouting results throughout the surface wave methods, pore water pressure measurement, and subgrade soil preloading evaluation. The results show that, after the improvement of permeability grouting operation, the performance indicators of all aspects of the subgrade soils have been improved to some extent, which shows that the slurry-water ratio improvement method proposed in this study is feasible and practical. It is hoped that this study can provide some reference for the improving the highway construction procedures in karst terrain.

Key words: karst terrain, foundation, permeability grouting, slurry-water ratio