Study on dynamic characteristics of cement-modified red mud-based silty soil under traffic load

Abstract

This study conducted dynamic hollow cylinder tests on cement-modified red mud-based fine sand soil (C-RMS) with the optimal proportion to broaden the resource utilization channels of red mud-based modified materials. The influences of various dynamic factors on the dynamic stress-strain relationship, cumulative plastic strain (ε_a), dynamic elastic modulus (E_d), and damping ratio (ξ) of C-RMS were studied. The research found that the dynamic stress-strain relationship of C-RMS has obvious nonlinearity and strain accumulation characteristics. The increase in the cyclic stress ratio (CSR) leads to the acceleration of strain development and the reduction of stability. The cyclic torsional shear stress ratio (η) significantly changes the displacement speed and shape of the stress-strain hysteresis curve. CSR has a significant impact on the development rate of ε_a, and CSR = 0.4 is the turning point at which C-RMS's resistance to deformation changes. The development rate of ε_a increases after CSR >0.4, indicating a nonlinear relationship between CSR and cumulative plastic deformation. Compared with CSR, η has a more significant impact on ε_a, E_d, and ξ of C-RMS. The increase of η leads to the increase of ε_a, the accelerated attenuation of E_d, and the ξ value is inversely proportional to the η value. The increase of vibration frequency (f) leads to the decrease of εa and the increase of E_d of C-RMS, indicating that the sample's resistance to deformation increases at high frequencies. The ε_a under the heart-shaped stress path is significantly higher than that under the triaxial stress path, and the constant ratio of cumulative strain is far greater than 1, showing the significant influence of the rotation of the principal stress axis on the accumulation of plastic strain.