PHYSICAL MECHANICAL INDEXES AND SWELLING PROPERTY OF WEATHERED TERTIARY MUDSTONE AT SHALLOW DEPTH IN NANNING

This paper examines the data of 201 projects for the tertiary mudstone in Nanning. The statistics for physical, mechanical and swelling indexes are obtained. A reference for parameters selection of underground engineering in Nanning is provided. The results show that the physical indexes can be used as constants for its low variability, in particular in the 95%confidence interval statistics. Mechanical indexes and swelling indexes data variability are bigger, which need to consider the variability. The tertiary mudstone in Nanning is a typical expansive rock and soil. It has high compressive strength, low compressibility, large shearing strength, and especially large cohesion force. In swelling indexes, the free swelling ratio of the mudstone in Nanning is lower compared with those in other cities. So it can be identified as weak swelling rock and soil. The swelling force is larger differently due to the rock composition and the difference of weathering degree. The parameters selection should be considered specifically when parameters selection.