To study the strength and deformation of municipal solidified sludge after different freeze-thaw cycles

the sludge solidified by CJYT-1 solidifying agent was tested through true triaxial tests. The stress-strain relationship and the strength and deformation characteristics after freeze-thaw cycles number of 0

1

3

5

8

10 are obtained

and the influence of intermediate principal stress ratio b and the number of cycles N on the soil strength parameters (including cohesion c′ and internal friction angle ?′ ) are studied. The results of the freeze-thaw cycle test show that the unconfined compressive strength and density of the solidified sludge gradually decrease with the increase of the number of freeze-thaw cycles

and the change slows down and stabilizes after 8 cycles. The cohesion and the internal friction angle both increase with the increase of b. Compared with b=0

when b=1

the growth rate of and can reach 16.77% and 12.3%

respectively. As the number of cycles N increases

the failure strength of the soil gradually decreases

and the failure stress ratio Mb generally decreases. The dilatancy of the specimen does not change significantly. The cohesion and internal friction angle decrease with the increase of freeze-thaw cycles N. Based on the two commonly used

Lade-Duncan and Matsuoka-Nakai failure criteria

combined with the true triaxial test data of solidified sludge

a failure criterion suitable for solidified sludge is proposed

and the -b relationship curve of the criterion is analyzed. Comparing the failure criteria proposed in the article

Lade-Duncan and Matsuoka-Nakai failure criteria

the test results are closer to the failure criteria in the article.