Composition Optimization and Action Mechanism of Tunnel Grouting Materials in Moraine Strata
The geological composition of the surrounding rock of the moraine layer tunnel is complicated,the overall cementation is poor,the structure is not uniform,and the surrounding rock collapse and water gusher are easy to occur during the tunnel excavation.Therefore,Portland cement was used as the main material,and magnesium oxide,xanthan gum,bentonite and water glass were added to optimize the components.A new cement-based grouting material suitable for the grouting conditions of the surrounding rock of the moraine layer was studied through the water out rate test,solidification test,fluidity test,mechanical test,expansion rate test and permeability resistance test,and the micro-morphology and consolidation mechanism of the grouting material were analyzed.The results show that the pores and crevices of the new grouting material are basically filled,the structure is tight,and the impermeability is relatively good.The introduction of Mg2+into the material can form Mg(OH)2 crystals to fill the micropore structure of the material and improve the anti-permeability mechanism of the material.A large number of fibrous C—S—H gels cement AFt,Ca(OH)2,Mg(OH)2 crystals and xanthan gum chelates into a whole,which greatly improve the material's permeability resistance.The excellent performance of the grouting material is verified by the field test.The material can effectively consolidate the loose stratum of the moraine and ensure the safety of tunnel excavation.
万方数据
维普
