Dynamic impact tests and temperature rise induced damage constitutive model of ice-rich frozen sandy soil

In this study, a soil-ice particle mixing method was used to prepare ice-rich frozen sandy soil specimens. Subsequently, the mechanical behaviors of ice-rich frozen sandy soil with a wide range of total moisture contents (15%-150%) were studied at three negative temperatures (-5, -10, and -15 degrees C) under the impact pressures from 0.2 MPa to 0.4 MPa. The melting of ice particles caused by the rise in temperature of frozen soil specimens was identified as temperature damage. Moreover, damage mechanism of ice-rich sandy frozen soil specimen during failure process was considered as the combined action of crack propagation and temperature rise. The analysis of the relationship between temperature rise value and dynamic strain was then calculated based on the heat conduction theory. Additionally, the phase transition equilibrium between unfrozen water and effective ice was used to determine the variation in ice volume content as the temperature rises, and the temperature damage variable was defined according to the reduction of dynamic elasticity modulus of ice-rich frozen sandy soil. Lastly, the compound damage variable was deduced and considered in the damage constitutive model. Accordingly, the theoretical and test data were compared to determine the model parameters. The results of the curve comparison indicate that the proposed model is feasible and suitable to be applied to predict the dynamic mechanics of ice-rich frozen sandy soil.