Tyoe of Slope Failure Identified from Pore Pressure and Moisture Content Measurements

Rainfall-induced landslides occur in many parts of the world and causing a lot of the
damages. For effective prediction of rainfall-induced landslides the comprehensive understanding of
the failure process is necessary. Under different soil and hydrological conditions experiments were
conducted to investigate and clarify the mechanism of slope failure. The failure in model slope was
induced by sprinkling the rainfall on slope composed of sandy soil in small flume. Series of tests
were conducted in small scale flume to better understand the failure process in sandy slopes. The
moisture content was measured with advanced Imko TDR (Time Domain Reflectrometry) moisture
sensors in addition to measurements of pore pressure with piezometers. The moisture content increase
rapidly to reach the maximum possible water content in case of higher intensity of rainfall, and higher intensity of the rainfall causes higher erosion as compared to smaller intensity of the rainfall. The controlling factor for rainfall-induced flowslides was density of the slope, rather than intensity of the rainfall and during the flowslide the sudden increase in pore pressure was observed. Higher pore pressure was observed at the toe of the slope as compared to upper part of the slope