Experimental Study on Shearing Strength of Sand Pebble in Southeast Tibet

In order to study the shearing strength characteristics of sandy pebble soil in southeast Tibet, this paper takes the sandy pebble packing of high road embankment of lalin high grade highway as the research object, and conducts particle analysis test on sandy pebble soil. On the basis of natural gradation, sand pebble soil was gradated and improved. In this paper, the undisturbed sand pebble soil and sand pebble soil with improved gradation were tested by direct shear tests under different vertical pressures.The results show that the stress-strain relationship of sandy pebble soil is mostly strain softening. The sandy pebble soil shears first,dilatancy occurs after,and the whole presents obvious dilatancy.The natural sandy pebble soil all has the phenomenon of grain deficiency,the shear strength of natural sandy pebble soil was improved by gradation. With the increase of the percentage of soil particle mass with a particle size of 20mm-60mm, the shear strength of sandy pebble soil increases accordingly. The physical and mechanical properties of sandy pebble soil was analyzed in this paper, which provides technical reference for the high embankment filling project in southeast Tibet.