Experimental Investigations on the Application of Compensation Grouting in Coarse-Grained Soils-Video

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Video Summary

Martin Weidner presents experimental research on compensation grouting in coarse-grained soils, where high permeability causes grout losses through infiltration and pore-space filling, reducing the volume available to lift the ground. A laboratory “filter press” test assessed grout suitability. Results showed that soil permeability strongly affects grout retention, while solid composition has little influence; reducing the water-to-solid ratio decreases grout losses.<br /><br />In a large-scale trial, researchers injected grout through sleeve pipes and excavated the resulting fractures. They observed horizontal, plate-like fractures near the pipes, alongside some longer, slender fractures. Repeated injections of small grout volumes gradually built up effective plate-like layers, while fewer injections of larger volumes produced longer, less effective fractures. Overall, the test achieved about 7% heave efficiency.<br /><br />For practice, the research recommends using grout with a low water-to-solid ratio and making numerous injections of small volumes, especially in coarse-grained soils.

Keywords

compensation grouting

coarse-grained soils

grout permeability

filter press test

fracture geometry

heave efficiency