Freeze-thaw damage mechanism of elastic modulus of soil-rock mixtures at different confining pressures

摘要

As a frequently-used roadbed filler, soil-rock mixture is often in the environment of freeze-thaw cycles and different confining pressures. In order to study the freeze-thaw damage mechanism of elastic modulus of soil-rock mixtures at different confining pressures, the concept of meso-interfacial freeze-thaw damage coefficient is put forward and the meso-interfacial damage phenomenon of soil-rock mixtures caused by the freeze-thaw cycle environment is concerned; a double-inclusion embedded model for elastic modulus of soil-rock mixtures in freezing-thawing cycle is proposed. A large triaxial test was performed and the influences of confining pressure and experimental factors on elastic modulus of soil-rock mixtures were obtained, and then the accuracy of the double-inclusion embedded model to predict the elastic modulus of soil-rock mixtures in freezing-thawing cycle is verified. Experiment results showed that as to soil-rock mixtures, with the increase of confining pressure, the elastic modulus increases approximately linearly. The most crucial factors to affect the elastic modulus are rock content and compaction degree at the same confining pressure; the elastic modulus increases with the increase of rock content and compactness; as the number of freeze-thaw cycles increases, the freeze-thaw damage coefficient of meso-structural interface and the elastic modulus decrease.