• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.45-52
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• 2015

With the rising interest in the environment, more attention on ecological restoration for damaged slope surface to restore its original state has been drawn. Generally, the most useful method is vegetation based spray work. This method uses green soil including sewage sludge, sawdust, paper sludge, and weathered granite soil. However, because there are neither accurate information nor test values about green soil, green soil is often lost by environmental factors such as rainfalls and strong winds. To solve the problem of green soil, it is necessary to prepare design standards about green soil, and conduct studies to deal with green soil loss in consideration of various variables including basic material property, soil quality of slope surface, and weather. This study was conducted in the mixture of green soil and eco-friendly soil stabilizer. With green soil, basic material property test and compaction test were conducted for the analysis on the basic characteristics of green soil. In the mixture with soil stabilizer at a certain ratio, we conducted shear strength test depending on the ratio in order to analyze the maximum shear strength, cohesion and the change in internal friction angles. Furthermore, in the mixture ratio of green soil and soil stabilizer, which is the same as the ratio in the shear strength test, an inclination of slope surface was made in laboratory for the analysis on erosion and germination rate. Finally, this study evaluated the most effective and economic mixing ratio of soil stabilizer to cope with neighboring environmental factors. According to the test, the shear strength of green soil increased up to 51% rely onto the mixing ratio of and a curing period, and its cohesion and internal friction angle also gradually increases. It is judged that the mixture of soil stabilizer was effective in improving shear strength and thereby increased the stability of green soil.

• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.109-134
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• 2006

Rocks undergo weathering processes influenced by changing in pressure-temperature condition, atmosphere, underground water, and rainfall. The weathering processes change physical and chemical characteristics of the rocks. Once the rocks are weathered, the characteristics of them are changed and, because of the changing, several disadvantages such as rock slope failures and underground water spouts are can occur. Before we cut a large rock slope, therefore, we must analyze current weathering conditions of rocks and predict weathering processes in the future. Through the results of such analyses, we can judge reinforcement works. In order to comply with such requests, chemical weathering sensitivity analysis which was analyzed from chemical weathering velocities and other characteristics of rocks has been applied in several prior construction works in Korea. But, It is defective to use directly in engineering fields because it was developed for soils(not rocks), it has too mny factors must be considered and the relationships between the factors are not clear, and it is hard to explain the weathering processes in engineering time range. Besides above, because it has been used for isotropic rocks, this method is hard to apply to anisotropic rocks such as sedimentary rocks. Acceding to studies from morphologists (e.g. Oguchi et al., 1994; Sunamura, 1996; Norwick and Dexter, 2002), time dependent strength reduction influenced by weathering shows a negative exponential function form. Appling this relation, one can synthesize the factors which influence the weathering processes to the strength reduction, and get meaningful estimates in engineering viewpoint. We suggest this weathering sensitivity characterization method as a technique that can explain time dependent weathering sensitivity characteristics through strength changes and can directly applied the rock slope design.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.63-79
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• 2008

Physicochemical characteristics of stream water, leachate, mine water and groundwater were investigated to estimate the influences of the tailing and waste rock from the abandoned Uljin mine area. Total extraction analysis and mineralogical studies were carried out to understand sulfide weathering and to determine the distributions of trace elements in the soil affected by mine waste (tailing, waste rock and leachate). The pH and EC value of the leachate from the tailing disposal ranged 2.9-6.0, $99{\sim}3,990{\mu}S/cm$, respectively, and the concentrations of dissolved major (up to 492 mg/l Ca; 83.8 mg/l Mg; 45.2 mg/l Na; 44.7 mg/l K, 50.8 mg/l Si) and trace elements (up to $826,060{\mu}g/l$ Fe; $131,230{\mu}g/l$ Mn; $333,600{\mu}g/l$ Al; $61,340{\mu}g/l$ Zn; $2,530{\mu}g/l$ Cu; $573{\mu}g/l$ Cd; $476{\mu}g/l$ Pb) were relatively high. The stream water showed the variation of dissolved metal concentrations in seasonally and spatially. The dissolved metal contents of the stream water increased by influx the leachate from the tailing disposal, but these of the down stream have been considerably decreased by mixing of dilute tributaries. The dissolved metal concentrations of the stream water at dry season (as February) were lower than these at rainy season (as May and July). These represent that the amounts of the leachate varied with season. However, stream water could not be effectively diluted by confluence with uncontaminated tributaries, because the flux of tributaries and streams reduced at dry season. Thus attenuations by dilution had been dominantly happened in rainy seasons. The order of accumulations of trace element in soils compared with background values revealed Mn>Fe>Pb>Cu>Zn. Sulfide minerals were mainly pyrrhotite, sphalerite and galena and chalcopyrite. Pyrrhotite was rapidly weathered along the edge and fractures, and results in the formation of Fe-(oxy)hydroxides, which absorbed a little amount of Zn.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.281-295
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• 2010

This paper deals with magnetic susceptibility, mineralogy, soil properties (pH, EC, CEC, loss on ignition), iron and manganese oxides, the content and partitioning of heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn), and their mutual relationship in the soil samples of an unpolluted, abandoned mine area, and industrial complex area. The various minerals derived from weathered bedrock were identified by X-ray diffraction in the unpolluted soil samples, except for the magnetic minerals. XRD analysis also revealed the existence of hematite and magnetite related to mine tailings and waste rocks in the abandoned mine area samples. The industrial complex area samples had carbonate minerals, such as calcite and dolomite, that might be due to anthropogenic deposition. The sum of the reducible, oxidizable, and residual fractions was over 80% for the abandoned mine area samples and over 50% for the industrial complex area samples using the sequential extraction method. The industrial complex area samples had a relatively high carbonate fraction that was associated with carbonate minerals. The content of aqua regia-extractable Fe, Mn, As, and Zn had a high positive correlation with the content of the dithionite-citrate-bicarbonate (DCB)-extractable method related to Fe/Mn oxide phases. The 54% and 58% of aqua regia-extractable Fe and As content, respectively, acted together with the concentrations of the DCB-extractable phases. Magnetic susceptibility values of total samples ranged from 0.005 to $2.131{\times}10^{-6}m^3kg^{-1}$. The samples including iron oxide minerals, such as hematite and magnetite, had a high magnetic susceptibility. The magnetic susceptibility showed a significant correlation with the heavy metals, Cd (r=0.544, p<0.05), Cr (r=0.714, p<0.01), Ni (r=0.645, p<0.05), Pb (r=0.703, p<0.01), and Zn (r=0.496, p<0.01), as well as Fe (r=0.608, p<0.01) and Mn (r=0.615, p<0.01). The aqua regia-extractable Fe and Mn content had a significant positive correlation with Cd, Cr, Cu, Ni, and Zn. However, the DCB-extractable Fe and Mn content had a significant positive correlation with As and Ni, indicating that the heavy metals were associated with Fe and Mn oxide minerals.