Investigation on the Nonlinear Strength Properties and Damage Statistical Constitutive Model for Frozen Sandy Soils

Abstract

ere are many flaws, such as fissures, cavities, and inclusions, in geomaterials, which make their mechanical properties with great randomness and uncertainty. Upon loading, the soil structure gradually losses the bearing capacity due to the transformation from microdefects to macroscopic breakage bands. Based upon the experimental data of frozen sandy soils, a new nonlinear strength equation between the first and third principal stresses was proposed, and then the nonlinear strength properties for frozen sandy soils in σ-τ plane were analyzed. In addition, by assuming that the microstrength of frozen sandy soil obeys the Weibull distribution function, a statistical damage constitutive model was established based upon the framework of continuum damage mechanics (CDM), with few parameters and a high accuracy. Compared with experimental data, the new model can well grasp the nonlinear strength properties and simulate the stress-strain relationships under different confining pressures for frozen sandy soils.

Establishment and Experimental Verification of Stress-Temperature Coupled Damage Model of Warm Frozen Soil

“…However, the peak stress of the a curve increases by 33.23% compared with the original curve, which is approximately twice the difference in the final result caused by a single parameter error. The data in Tables 4 and 8 show that a small change in confining pressure and temperature leads to a relatively small range of m and a values; however, the final result is highly sensitive to a change in these two parameters [24]. When the binary polynomial fitting is used, the error of the parameter simulation values further increases compared with those of the single variable polynomial fitting.…”

“…In the application of the frozen soil damage model, m and a are often regarded to only be related to confining pressure σ 3 [9,24], and the following relationship can be obtained:…”

“…The Mohr-Coulomb theoretical analysis is used to determine the extent of damage characterization F [9]. In triaxial compression tests under low confining pressure, the Mohr-Coulomb shear strength formulation can be expressed as follows by axial stress σ 1 and confining pressure σ 3 [24].…”

“…Therefore, the Mohr-Coulomb criterion was introduced to assess the damage state of warm frozen soil elements, and a 1-D parameter expression was derived and achieved good results. The constitutive study of warm frozen soil has consistently focused on deformation development under the action of a single stress factor, and temperature has been considered to be a fixed condition rather than an action factor, which limits the application scope of the constitutive model ( [17]; Zhang, D et al, 2018). Previous studies on the coupled effects of stress and temperature have mainly focused on the level of physical field control relations, whereas investigations of a deeper constitutive model have occurred less frequently [14,18].…”

Correction method of Mohr-Coulomb strength criterion for rock based on freeze-thaw and residual effects

“…According to statistics and continuous damage mechanics theory, a damage constitutive model that can reflect the whole failure process is established (Zhang D, 2018 [9]). Under the combined action of multiple factors, based on the statistical strength theory and the principle of damage mechanics, H-B criterion and Mises criterion are taken as the rock strength criteria respectively, and the rock damage evolution considering the combined action of temperature and load is constructed (Zhang HM, 2014 [10]; Yu ST, 2018 [11]). The static elastic modulus method is used to characterize the freeze-thaw damage of rocks.…”