Rainfall Effects on Pore Pressure Changes in a Coastal Slope of the Serra do Mar in Santa Catarina

A.A.M. González, L.B. Passini, A.C.M. Kormann

Article

Soils and Rocks, São Paulo, 40(3): 263-278, September-December, 2017 | PDF


Abstract

This research aims to describe how rainfall can cause changes in the piezometric pore pressure and soil matric suction in a densely instrumented slope by the South BR-101 (Brazilian Numbered Highway), in the area of Morro do Boi, in the State of Santa Catarina, South Region of Brazil. The slope presented a history of instability movements instigated by intense rainfall, with debris accumulation on the highway and traffic interruption. The analyzed data are measured by six vibrating wire piezometers and eight electrical tensiometers attached to a datalogger, two conventional slope inclinometer sand a rain gauge with an internal datalogger. A total of 2,552 readings corresponding to the vibrating wires and electrical resistance instruments, 29 inclinometers records and 7,143 rainfall records were collected over the first ten months of slope monitoring. The analysis results demonstrated that during the monitoring period there were no heavy rains. Three monitoring periods were identified by the frequency and intensity of rainfalls. The soil pore pressure monitoring instruments showed significant variations in the high frequency period and low intensity rainfall, and little variation in low frequency period and high intensity rainfall, which demonstrates greater runoff and little infiltration during the occurrence of more significant rainfall.


Submitted on April 6, 2017; Final Acceptance on September 21, 2017; Discussion open until April 30, 2018. DOI: 10.28927/SR.403263