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| Experimental study on physical properties of silica soil and grouting modified mudstone |
| CHAI Zhaoyun，LIU Xu，YANG Pan，GUO Ruiyu，YANG Zeqian，LIU Xiangyu |
| (Key Laboratory of In-Situ Property-Improving Mining of Ministry of Education，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China) |
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Abstract Based on the viscosity and gel time，wettability and affinity of silica sol，and it?s gel deformation and strength were characterized，an experimental system of steady pressure grouting was developed. The law of grouting permeability of silica sol in mudstone and the evolution law of strength，pore fracture and permeability of grouting modified mudstone were studied. The results show that after adding catalyst，the viscosity of silica sol increases composite exponentially with time，and the gel time is related to the content of SiO2 and Na2O of silica sol and the amount of catalyst，the smaller the content of SiO2 and Na2O and the amount of catalyst is，the longer the gel time is. There is a certain phenomenon of dry shrinkage after silica sol gel，and the smaller the humidity of the curing environment is，the more serious the dry shrinkage is. The stress-strain curve of gel is similar to that of rock materials，and there are stress drop in pre-peak and post-peak. With the extension of curing time，the strength of gel increases，and the brittleness characteristic becomes more and more obvious during failure. After grouting，the uniaxial compressive strength of rock samples decreases in varying degrees，and is negatively related to grouting pressure and time. Under the same conditions，the strength increases with the increase of SiO2 and Na2O content in silica sol. The failure mode changes from the shear splitting failure before grouting to the coexistence of shear slip failure，fracture failure and drum failure after grouting. The pore shape distribution of rock samples has little change before and after grouting，but the pore volume of pore size larger than 20 nm pore is smaller than that before grouting，and permeability decreased significantly.
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2021, Vol. 40 
