Size effect on mudstone strength during the freezing–thawing cycle

A series of single-particle crushing tests was carried out to investigate the size effect of coarse-grained mudstone soil strength with three categories of nominal particle size, 2·5, 5·0 and 10·0 mm, during various numbers of freezing–thawing cycles. On the basis of test results, the main crushing mode of a single mudstone grain and the correlation between the given characteristic stress and the probability of survival were determined. The results also indicated that the strength of a single particle decreases with increasing nominal particle size and an increasing number of freezing–thawing cycles. Moreover, the Weibull modulus was calculated to examine the applicability of the Weibull distribution on the single-particle failure strength of a mudstone grain. The results revealed that the Weibull modulus decreases slightly with an increase in the number of freezing–thawing cycles, and the test data are accurately described by the Weibull distribution. It was further concluded that the relationship between particle size and characteristic stress and the average failure force, considering the Weibull modulus, can be predicted by the size effect.