Angle of repose of landslide debris deposits induced by 2008 Sichuan Earthquake

The angle of repose is defined to be the angle made by the heap of the granular deposited materials in the slope or the run-out of the deposits. Present study focuses on the angle of repose of landslide debris deposits induced by the 2008 Sichuan Earthquake in China. The angle of repose was measured in the field and tested in laboratory, respectively. The angles of repose of 87 landslide debris deposits along the left bank of the Minjiang River from Yingxiu to Wenchuan County (that is the location of the earthquakeʹs epicenter) in Sichuan Province, China, were measured based on the laser measurement device. The range of the measured angles was 28.8° to 44.7°, with the statistical arithmetic average value 35.5°. The angle of repose was also tested in laboratory by using a very simple manual test. The value of the angle of repose obtained in laboratory is larger than that in the field. Also investigated are the factors influencing the angle of repose, including the relative compaction, particle size, and non-uniformity.