Geotechnical Characteristics of Volcanic Red Clay Soil Related to Geoengineering Problem in Sekincau, Sumatra, Indonesia

Abstract

The study of physical, mechanical, and mineralogy characterization of volcanic red clay soil
in the Sekincau Sub-District, West Lampung, Indonesia to obtain the genetic and soil
engineering characterization related to the geoengineering problem. The method of this study is
the Geotechnical laboratory method, XRD, and SEM method. The results of the analysis show
that the volcanic red clay soil in the study area is residual soil produced from the weathering of
volcanic rocks composed of felsic minerals in tropical environments. This soil is clayey silt
(MH), loose, easily eroded, has the specific gravity 2.52 - 2.90, water content 27.21% - 67.14%,
water saturation 72.98% - 94.75%, porosity 54.43% - 67.00%, the liquid limit value of 52.54-
121.17%, a plasticity index value of 17.82-35.17%, permeability 7.4E-08 - 7.22E-05, has
cohesion less than 1 Mpa, and an internal friction less than < 30o. Quartz, halloysite, kaolinite,
and montmorillonite are the clay minerals that can be found in this soil. It can be concluded that
volcanic red clay soil in the study area is easy to landslide during the rainy season.