Analyses on variations in the unsaturated characteristics of a mine waste-dump slope during rainfall
- 244 Downloads
Field measurement units and a system were constructed and installed in a waste-dump slope at the Imgi mine to investigate and analyze the variations in the unsaturated characteristics of the soil. The field instrumentation system was composed of a data acquisition system, a solar system, and measuring sensors. The rainfall, matric suction, and volumetric water contents were continuously measured from the units in the instrumented site and analyzed with the soil water characteristic curve (SWCC) estimated from laboratory experiments. The variations in matric suction and volumetric water content were primarily affected by the rainfall intensity. At the surface of the slope, the largest increase and decrease in the changes in matric suction and volumetric water content were observed during the wetting and drying processes, respectively. The matric suction and volumetric water content measured from the instrumented area were compared with the SWCCs obtained from the laboratory test, and the measured data were located between the drying and wetting paths. The drying and wetting paths obtained from the laboratory test are regarded as primary drying and wetting curves, respectively. Therefore, the measured data can be defined as scanning curves, which are located between primary drying and wetting curves. The variations in matric suction according to volumetric water content were dependent on depth, and a wide range of variations was observed at shallow depths. It was confirmed that the unsaturated soil near the ground surface has the sensitive reaction induced by the infiltration and evaporation in nature.
KeywordsField monitoring Matric suction Rainfall Volumetric water content Waste-dump slope
This research was supported by the Basic Research Project (Grant No. 16-3413) of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Science, ICT, and Future Planning of Korea.
- Chae BG, Seo YS (2012) An alternative method for landslide early warning based on gradient of volumetric water content in unsaturated soil. Proc XI international symposium on Landslides, Banff, Alberta, Canada, vol 2, pp 1457–1463Google Scholar
- Feng M, Fredlund DG (1999) Hysteretic influence associated with thermal conductivity sensor measurements. Proc from theory to the practice of unsaturated soil mechanics, in association with 52nd Can Geotech Conf and Unsaturated Soil Group, Regina, Canada, pp 14:2:14–14:2:20Google Scholar
- Gasmo J, Hritzuk KJ, Rahardjo H, Leong EC (1999) Instrumentation of an unsaturated residual soil slope. Geotech Test J 22:128–137Google Scholar
- Hilf JW (1956) An investigation of pore water pressure in compacted cohesive soils. Technical memorandum, no. 654. U.S. Department of the interior, Bureau of Reclamation, Design and Construction Division, Denver, COGoogle Scholar
- Kim MI, Chae BG, Cho YC, Seo YS (2008) Study on rainfall infiltration characteristics for weathered soils: analysis of soil volumetric water content and its application. J Eng Geol 18:83–92 (In Korean with English abstract) Google Scholar
- Lee IM, Cho WS, Kim YU, Sung SG (2003) In-situ monitoring of matric suctions in a weathered soil slope. J Korean Geotech Soc 19(1):41–49 (In Korean with English abstract) Google Scholar
- Lu N, Likos WJ (2004) Unsaturated soil mechanics. Wiley, New YorkGoogle Scholar
- Mofiz SA, Sarkar DC, Rahman S, Awall MR, Taha MR, Hossain MK (2005) Instrumentation and matric soil suction measurement in a decomposed granite soil slope. Proc of the advanced experimental unsaturated soil mechanics, Trento, Italy, pp 527–532Google Scholar
- Smith JB, Godt JW, Baum RL, Coe JA, Burns WJ, Lu N, Morse MM, Sener-Kaya B, Kaya M (2014) Hydrologic monitoring of a landslide-prone hillslope in the Elliott State Forest, Southern Coast Range, Oregon, 2009–2012: U.S. Geological Survey Open-File Report 2013–1283, p 61. doi: 10.3133/ofr20131283
- Song YS, Lee NW, Hwang WK, Kim TH (2010) Construction and application of an automated apparatus for calculating the soil-water characteristics curve. J Korean Geotech Soc 20:281–295 (In Korean with English abstract) Google Scholar