Abstract: Pre-disintegrating carbonaceous mudstone has been widely used in the embankment engineering as embankment filler in Southwest China. In order to study the deformation and strength characteristics of pre-disintegrating carbonaceous mudstone under loading and soaking condition, a new type of wetting deformation test device is developed. A series of deformation tests on pre-disintegrating carbon mudstone samples are carried out according to the orthogonal experimental design. The test results show that the pre-disintegrating carbon mudstone will exhibit a large vertical deformation at initial loading and first immersion, which consists of both compressive induced deformation and wetting induced deformation. The influences of vertical load, cycle number, immersion time, compactness and moisture content on the maximum vertical deformation of pre-disintegrating carbon mudstone decrease in sequence. The variation of shear strength during wetting deformation is mainly due to the change of cohesion. The influence level of cycle number, immersion time, vertical load, compactness and moisture content on cohesive strength of pre-disintegrating carbon mudstone decreases accordingly. The shear strength decreases sharply first and then tends to be stable with the increase of the vertical deformation. The function relation between shear strength and vertical deformation is obtained. The results can provide some references for deformation calculation and engineering practice of carbonaceous mudstone.

Key words: embankment engineering, carbonaceous mudstone, orthogonal experiment, wetting deformation, shear strength