Mechanical characteristics of intact Middle Pleistocene Epoch loess in northwestern China

Abstract

In order to research the mechanical characteristics of intact Middle Pleistocene Epoch loess, triaxial shear tests and isotonic compression test of intact Middle Pleistocene Epoch loess were conducted by improved SJ-1A triaxial shear equipment. According to test results, it can be found that the intact Middle Pleistocene Epoch loess has the properties of shear dilatancy and shear shrinkage. With the increase of confining pressure, stress-strain curve develops from softening to hardening. The failure mode of intact Middle Pleistocene Epoch loess is shear failure with the rupture angle between 55° and 61°. And it is better to determine the yield stress (p_y, q_y) of the intact loess under different confining pressures by using the ɛ_v-q/p curve. Along with the increase of confining pressure, yield deviatoric stress q_y and yield spherical stress p_y present logarithmic relationship. Besides, the strength parameters, elastic modulus K and G of intact loess, are obtained, which are benefit for loess projects design.

Keywords

yield stress / compression testing / failure model / Middle Pleistocene Epoch loess

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