Scale Effect on Failure Characteristics of Sandy Pebble Soil

Because of discontinuity and heterogeneity of sandy pebble soil, the mechanical characteristic is different from the other homogeneous mediums`. Scale effect should be consisted. By means of the direct shearing test and heavy compaction test, shear strength characteristics of sandy pebble soil with different gradation and maximum particle size are analyzed. The results are as follows: (1) The large particle size has important influence on the shearing indexes; (2) The cohesion becomes increased with the well gradation. The friction angle is on the contrary; (3) The cohesion will be reduced if improving the maximum particle sizes. However the friction angle will be increasing.