FACTORS INFLUENCING SOIL BEHAVIOR AND PROPERTIES OF MASS MOVEMENTS IN THE BLIMBING AREA, BRUNO DISTRICT, PURWOREJO REGENCY, CENTRAL JAVA, INDONESIA

Kusumayudha, Sari Bahagiarti and Jumadilakhir, Riskhy and Purwanto, Purwanto (2022) FACTORS INFLUENCING SOIL BEHAVIOR AND PROPERTIES OF MASS MOVEMENTS IN THE BLIMBING AREA, BRUNO DISTRICT, PURWOREJO REGENCY, CENTRAL JAVA, INDONESIA. Geographia Technica, 17 (1). pp. 33-45. ISSN 2065-4421

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Abstract

The Blimbing area, Bruno district of Purwrejo Regency, Central Java, belongs to a susceptible area for
mass movement. Its geomorphology expresses homoclinic hills, undulating plains, and denudated
volcanic hills. The lithology is composed of sandstone of the Halang Formation and andesite breccia
of the Peniron Formation. A study was conducted that aimed to examine the factors influencing soil
behavior and mass movements in this area by applying an analytical descriptive method along with a
field survey and surface mapping. There were eight slopes, namely Slope 1 to Slope 8, being examined
and analysed. Slope 1 and Slope 5 are composed of high-plastic clay with very expansive properties.
Slope 2 is occupied by high-plastic silt with slightly expansive properties. Slope 3, Slope 4, Slope 6,
and Slope 7 comprise high-plastic silt with slightly expansive to very expansive properties, while Slope
8 is built of highly fractured rock, with a joint density of 0.36 m. Using the simplified Bishop method,
it can be determined that Slope 1 to Slope 7 have safety factor values of 1.095, 1.369, 1.262, 1.128,
1.605, 1.095, and 0.961, respectively. Slope 8 has a rock mass rating (RMR) value of 38, which belongs
to class IV (poor rock). It has the potential for wedge and toppling failures. Results of this study indicate
that the existence of water in the slopes increases the load on the slopes by 15%, decreasing the
cohesion force and reducing the friction angle values, especially when the water content is more than
70%. The type of soil is in the form of high-plastic clay and high-plastic silt that is slightly expansive
to very expansive, with low permeability. Thus, water content and the very expansive soil are the main
influencing factors for mass movements in the study area.

Item Type: Article
Uncontrolled Keywords: Soil behaviour, Expansive clay, Poor rock, Water content, Mass movement.
Subjects: Q Science > QE Geology
Divisions: Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User: SARI BAHAGIARTI KUSUMAYUDHA
Date Deposited: 07 Jun 2022 01:42
Last Modified: 07 Jun 2022 01:43
URI: http://eprints.upnyk.ac.id/id/eprint/29963

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