Abstract
To obtain the dynamic mechanical properties of frozen sandstone at different temperatures (i.e., 20°C, −10°C, −20°C, and −30°C), dynamic uniaxial compression tests of saturated sandstone are conducted using a split‐Hopkinson pressure bar. The experimental results demonstrated that the brittleness of the saturated sandstone increased and its plasticity weakened with a decrease in temperature. The peak strength and dynamic elastic modulus of the sandstone were positively correlated with its strain rate. The peak stress was most sensitive to the strain rate at −10°C, and the elastic modulus was most sensitive to the strain rate at −30°C. According to the evident segmentation characteristics of the obtained stress‐strain curve, a viscoelastic dynamic constitutive model considering the strain rate effect and temperature effect is developed; this model combines a nonlinear (or linear) body and a Maxwell body in parallel with a damage body. The applicability of the constitutive model is also verified using experimental data. The fitting results were demonstrated to be in good agreement with the experimental results. Furthermore, the fitting results serve as reference for the study of the constitutive model of weakly cemented soft rock and the construction of roadway freezing methods.
Highlights
Introduction eJurassic coal seam in western China is covered in thick cretaceous water-rich sandstone
Test Principle. e basic principle of the split-Hopkinson pressure bar (SHPB) system is the propagation theory of stress waves in an elastic rod, which is based on the one-dimensional (1D) elastic wave hypothesis and uniformity hypothesis
Dynamic Elastic Modulus Analysis. e elastic modulus of the rock has an evident correction to the strain rate in the impact test. erefore, the elastic modulus can be defined as the secant slope of 40%∼60% or a tangent slope at 50% of the peak stress
Summary
En, the UTA-2000A ultrasonic analyzer was used to select rock samples with similar longitudinal wave velocities as the test samples. E basic principle of the SHPB system is the propagation theory of stress waves in an elastic rod, which is based on the one-dimensional (1D) elastic wave hypothesis and uniformity hypothesis. Where εI(t), εR(t), and εT(t) are the incident strain, the reflected strain, and the transmitted strain during impact, respectively; Ec, Ac, and Cc are the modulus of elasticity, the cross-sectional area, and the longitudinal wave velocity of the bar, respectively; and As and ls are the cross-sectional area and the length of the sample, respectively. E impact velocities of the striker were determined to be 3.0 m/s, 3.5 m/s, 3.8 m/s, 4.6 m/s, 5.2 m/s, and 6.0 m/s based on the monitoring data at different positions of the frozen wall during tunneling at the construction site.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
