Monitoring the Change of Structures in Frozen Soil in Triaxial Creep Process by CT
Ma Wei, Wu Ziwang, Pu Yipin and Chang Xiaoxiao (State Key Laboratory of Frozen Soil Engineering, LIGG CAS, 730000)
In this paper, monitoring and analyzing the change of structures of frozen soil in triaxial creep process by CT is presented. It is found that the confining pressure restrains the increase of cracks in frozen soil and enhances the strengthening action of structure so that the strengthening of structure occupies a dominant position at unstable and stable creep stages of frozen soil. With a further accumulation of non-elastic deformation in frozen soil, if the strengthening of structure still occupies a dominant position, the creep deformation attenuates, and if the softening action can overcome the action of confining pressure, the creep deformation becomes an unattenuated one. The breaking appears firstly in the weakened area with low density within the sample, and the tensile cracks is found in the sample surface and then propagates inwards to cause an integral failure of the structure at last.