Elevation Angles, Soil Textures, Soil Settlements and Water-Holding Capacity on Landslides: An Experimental Case Study in the Province of Iloilo, Philippines

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International Journal of Research and Innovation in Applied Science (IJRIAS) |Volume VIII, Issue III, March 2023|ISSN 2454-6194

Elevation Angles, Soil Textures, Soil Settlements and Water-Holding Capacity on Landslides: An Experimental Case Study in the Province of Iloilo, Philippines

Donna Hembra Gabor
Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas
DOI: https://doi.org/10.51584/IJRIAS.2023.8302
Received: 26 February 2023; Accepted: 10 March 2023; Published: 08 April 2023

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Abstract— The soil textures, soil settlements, soil water-holding capacity, and elevation angles are parameters for landslides in the Province of Iloilo. They are usually triggered during heavy rainstorms, causing severe property damage and sometimes causing casualties. This experimental study aims to determine how these parameters are factors for landslides and flood monitoring and uses three methods to provide ease and continuity of measurements. The Fourier transforms infrared (FTIR)spectroscopy analysis for soil textures, the Imhoff cone for the settling and water-holding capacity of the soil, and an improvised apparatus to test how the slopes affect the transportation of soil materials. FTIR Soil analysis reveals that contents of clay and organic matter directly affect soil water-holding capacity due to the larger surface area. The smaller particle sizes, such as clay, have a larger surface area leading to a higher water-holding ability. A landslide-prone zone has a lesser settling time except for the sand that settles fastest due to larger masses. An angle of 20 degrees has more mass movement too much higher slopes like 55 and 85 degrees. The increase in height or angle of the elevation decreases stability, leading to less mass movement. Less mass movement leads to the conclusion that there are rare landslides in the very high slope range due to fewer vibrations or soil movements caused by human activities and being compact or stable. This study is crucial for forecasting and preventing geohydrological processes and developing better landslide warning strategies to mitigate risks and reduce socioeconomic damage.

Keywords— Landslide, FTIR soil analysis, spectroscopy, imhoff cone, elevation

I. Introduction

Landslides are one of the world’s geohazards that threaten both exposed areas in urban and rural areas and cause severe consequences on human lives and economic losses. Due to climate change, there is an increase in the frequency and intensity of heavy rainfall along with a shift of locations and recurrence of heavy rain that increases landslide risk in landslide-prone areas. Expansion of urban areas due to population growth, redevelopments of mountains, and shortening of the coastal area caused by roads and railways constructions and deforestation increase exposure to the landslide hazard (Pajalic, Peranic, Maksimovic, Ceh, Jagodnik, Arbanas, 2021). There are so many factors that cause landslides to happen. One factor is soil quality which includes its physical and chemical properties. Second is the soil water holding capacity and settling ability. Lastly, the angle of elevation can be evaluated statistically and interpreted.
A landslide refers to the slow or rapid downward movement of a soil mass due to gravity. It is triggered when the shear stresses developed inside the soil exceed those which can resist. Landslides are caused by the liquefaction of small grain silt sand layers or due to a general failure in combination with increased loads due to an earthquake, increased pore pressure, and reduction in the available shear strength of the soil. In particular, Panay island is prone to typhoons, storm surges, and flash floods which constantly suffer from the effects of the outbreak of such destructive phenomena. For this reason, it is necessary to monitor the sources of landslides, and the mechanisms they present, to proceed with the analysis of stability and the calculation of safety factors (Dariagan, Atando, & Asis, 2021).

On the other hand, the soil is a heterogeneous system, an upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles. Soil mechanisms and processes are complex and back-breaking for you to be understood and require analytical techniques. Some traditional methods describe the relationship between soil properties such as physical, chemical, and its main soil components. Simple and accurate soil testing procedures in the field and laboratory are necessary for advanced research in landslide monitoring. (Mohamed, Saleh, Belal, & Gad, 2018). The Fourier transform infrared (FTIR) spectroscopy is a unique tool for mineral and organic components of soil samples. The FT Infrared spectroscopy offers a sensitive characterization of minerals and soil organic matter (SOM) and mechanistic and kinetic aspects of mineral–SOM interactions that underlie biogeochemical processes (Margenot, Calderón, Goyne, Mukome, & Parikh, 2017).