动水环境下改性水泥黏土注浆材料性能试验研究OA

Grouting technology is a crucial method for mitigating karst water inrush disasters.However,traditional grouting materials have obvious limitations in dealing with high-pressure and high flow dynamic water environments,such as poor anti-dispersion ability,improper control of setting time,and slow strength development,which make it difficult to form effective sealing in dynamic water environments.The development of new high-performance grouting materials that can adapt to harsh hydrogeological conditions has become an urgent need in the field of geotechnical engineering.Based on a series of laboratory tests and self-designed anti-erosion test system with natural rock fracture characteristics,the rheological properties,thixotropy,erosion resistance,initial setting time,volume shrinkage rate,and compressive strength of cement paste were investigated for grouting materials(pure cement,cement clay,and modified cement clay)with different water to solid ratios,clay contents,and modifier dosages.The modification mechanism of modified cement clay grouting materials was revealed through scanning electron microscopy experiments.A modified clay cement grouting material with good anti-erosion performance in a dynamic water environment has been selected.The findings indicate that the optimal mix ratio for the new high-performance modified clay-cement-based grouting material is water∶cement∶clay=2∶1∶1,with a modifier dosage of 0.75%.The dosage of the modifier significantly improves the flowability and compressive strength of grouting materials,which can meet the grouting needs in high-pressure and high flow dynamic water environments.At a flow velocity of 1.2 m/s,the scour retention rate of modified cement-clay slurry increases by 30%compared to cement slurry.The addition of modifiers effectively reduces the dispersibility of the slurry,making the solid denser and more uniform,especially suitable for rapid water flow erosion scenarios such as karst water inflow.Cement-clay slurry exhibits the longest initial setting time,followed by pure cement slurry,while modified cement-clay slurry has the shortest initial setting time.The volume shrinkage rates of modified cement-clay grouting materials are only 15.21%and 24.14%of those of cement-based and cement-clay grouting materials,respectively.The compressive strength of the modified cement clay slurry at 3rd,7th,and 28th days of age is 171%,145%,and 141%of the cement-clay slurry,respectively.Comparison of compressive strength of various grouting materials under different curing ages obtains cement slurry cement stone>modified cement-clay slurry cement stone>cement-clay slurry cement stone.The research results provide reliable technical support for the application of grouting in karst water inrush disaster prevention.