关键词: 水泥改良风积砂, 动力特征, 动力损伤, 西原模型, 滞回曲线

Abstract: To study the effect of cement content on the improvement of aeolian sand and its dynamic characteristics under different negative temperatures and frequencies, uniaxial, dynamic cyclic loading and creep tests were carried out. 7 days and 28 days uniaxial compressive strengths of improved aeolian sand with different cement contents were obtained to determine the optimal amount of cement by combining with frost heave variation with time. Hysteretic curve of different times was measured through the dynamic cycle test. Dynamic modulus attenuation, dynamic evolution damage and damping ratio evolution law of improved aeolian sand were determined. Parameters in the Nishihara model describing the rheological characteristics of hysteretic curves were determined by rheological experiments. Evolution equation before and after yielding hysteresis curve was established and time division standard was given for each loop. The electron microscope observation showed that the flocculent connection structure between the sand particles increased the bond strength between the particles and effectively inhibited the development of dynamic damage. The negative exponential model can be used to describe the dynamic modulus attenuation characteristics of the improved aeolian sand, and the damping ratio increased with the loading times, and finally tended to a certain value. Nishihara model considering the influence of was derived. The loading equation of the hysteresis curve was established based on the actual loading characteristics. The least squares principle can be used to identify rheological parameters.

Key words: cement improved aeolian sand, dynamic characteristics, dynamic damage, Nishihara model, hysteretic curve