Effect of Antecedent Rainfall on Slope Stability- A Case Study of Haflong Hill, North East India
- PDF / 1,945,828 Bytes
- 5 Pages / 595 x 842 pts (A4) Page_size
- 93 Downloads / 211 Views
Effect of Antecedent Rainfall on Slope Stability- A Case Study of Haflong Hill, North East India Deka, A.1,*, Daulagupu, R.2, Brahma, H.3, Lodger, H.4, and Dutta, D.5 Department of Civil Engineering, Central Institute of Technology Kokrajhar, Kokrajhar -783370, India E-mail: [email protected]*; [email protected]; [email protected]; [email protected]; [email protected]
ABSTRACT The accurate determination of factor of safety is important to find out the stability of slopes. Out of the many factors which are responsible for slope failure in hilly areas continuous rainfall, particularly, is one of the major important factor responsible for triggering landslide. Slope is an exposed ground surface that stands at an angle with the horizontal. In this study, a part of the hill of Haflong, the head quarter of Dima Hasao district in the state of Assam, India are chosen. Two types of transient analysis i.e., uncoupled analysis and coupled analysis were carried out. The coupled analysis considers the deformation of the soil surface with time when rain water passes through the soil mass. Three slope angles 30°, 45° and 90° were considered for both the case. The results shows that the factor of safety decreases with increase in the period of rainfall and slope angle, whereas the factor of safety increases slightly during coupled analysis which is due to the combined effect of deformation and seepage. INTRODUCTION Slope failure has been a major concern in hilly arears during rainy season and a lot of research has already been conducted to find out the main causes responsible for it and possible measures. Some of the main factors responsible for failure of slope are precipitation, infiltration, evaporation, and transpiration etc. (Kristo et al., 2017; Nalina et al., 2014). In tropical regions where rainfall continues over a long period, the main factor responsible for triggering landslides is the rainwater. When rainwater infiltrates into the soil pores through the slope surface, the strength of soil decreases continuously resulting in the instability of slopes (Cho and Seung, 2002; Schmertmann, 2006; Adrin et al., 2007; Rahardjo et al., 2007; Rahimi et al., 2011; Yanmei et al., 2015; Kaixi et al., 2016). The pore water pressure which is the major factor in keeping the strength of soil, changes continuously due to continuous rainfall. As a result the soil mass starts losing its strength creating a failure surface at a point of time. Although it has been identified as a cause of rainfall-induced slope failure, the pattern or distribution of the antecedent rainfall has not received adequate attention. So, in order to understand the above condition, the present study was carried out to find out the stability of hill slope due to continuous rainfall pattern. A hill slope was selected for the present study as shown in Fig.1. The name of the site is Haflong, the head quarter of Dima Hasao district in the state of Assam, India. Haflong is located at coordinate 25.3478°N93.01176°E. It has an average elevation of 966
Data Loading...
