Experiments and analytical method for landslide scarp caused by water-induced weakening of basal sliding zone.

The aim of this study was to investigate the location of the landslide scarp surface induced by water weakening of sliding zone soil and to propose an analytical method to calculate the location. Eight laboratory model tests were performed to reproduce such landslide scarp surfaces and to demonstrate a relationship between the location of scarp surface and the weakened sliding zone. Based on this relationship and the Bishop interslice force assumption, an analytical method was proposed to calculate the locations of laboratory-reproduced scarp surfaces. Finally, the analytical method was applied to real landslide scarp surfaces to assess its practical effectiveness. The inclined angles of scarp surfaces observed in the eight tests exhibit a wide range, varying from 63.9° to 80.9°, due to differences in the properties of the weakened sliding zone and the sliding mass. The calculated results for all the laboratory and real scarp surfaces reveal only one valley point at which the local lowest safety factor (SF) reaches its lowest value. This lowest value indicates the critical scarp surface, thus demonstrating that the critical scarp surface is readily found by using the analytical method. The locations of the calculated critical scarp surfaces are broadly consistent with the measured or published locations of laboratory and real scarp surfaces. When applied to real landslide scarp surfaces, the analytical method locates the critical scarp surface by using available scarp outcrop data. [ABSTRACT FROM AUTHOR]