Subjects: Mechanics >> Applied Mechanics submitted time 2022-12-21 Cooperative journals: 《应用力学学报》
Abstract：
Rock mass in cold regions is often affected by the combined effects of dynamic loading and low temperature; therefore,it is of great importance to study the dynamic mechanical response of rocks under low temperature conditions for geotechnical construction in cold regions.First,the water-saturated siltstone specimens were frozen to different negative temperature levels(from -10 ℃ to -50 ℃),and then dynamic impact tests were carried out on the water-saturated specimens at low temperatures using the split Hopkinson pressure bar(SHPB)system to study the changes in the deformation characteristics and mechanical properties.Finally,the dynamic constitutive model of frozen siltstone considering the strain rate and low temperature effect was established.The results show that the crack closure strain of the specimen increases with the increase of strain rate,while the elastic strain and plastic strain do not change significantly with the strain rate.The dynamic elastic modulus and compressive strength show a trend of increase and then decrease with the decrease of the sub-zero temperature,and reach the maximum value at -30 ℃.The mechanical properties of frozen rocks depend on the content of water/ice mixture inside the frozen siltstones and the resulting combined weakening and strengthening effects.The proposed constitutive model considering the strain rate and low temperature effects can better fit the full stress-strain relationship of frozen siltstone strain rate(>150 s-1).
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