• Land and Housing Review
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• v.9 no.2
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• pp.51-57
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• 2018

The causes of landslides are dependant on rainfall events and the soil characteristics of a slope. For the conventional slope stability, the slope stability analysis has been carried out assuming the saturated soil theory. But, in order to clearly explain a proper soil slope condition by rainfall, the research should be performed using the unsaturated soil mechanism suitable for a soil slope in the field. In the study, by using two major categories of soils in Korea, such as granite and gneiss weathered soils, landslide model test and finite element method have been compared with the difference of seepage and soil stability analysis. The hydraulic conductivity of gneiss weathered soil is slower than that of granite weathered soil, and the gneiss weathered soil contains much finer soils than the granite weathered soil. It was confirmed that the instability of the slope was progressing slowly due to the slow rate of volumetric water content of the surface layer.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.2
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• pp.121-135
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• 2016

The present study is an analysis of the monitoring results of the four areas that underwent the experimental construction of Straw-net+seedspray, Vegetation media spray method(t=2cm), and Vegetation media spray method(t=3cm), with the purpose of selecting the adequate revegetation of cutting slopes in weathered granite soil. Cutting slopes are mostly designed in the Straw-net+seedspray method, but since weathered granite soil slopes tend to have an infertile soil quality that runs down, it is difficult for seed germination and growth. It is difficult to apply Straw-net+seedspray to weathered granite soil slopes considering the germination rate and coverage rate of the Straw-net+seedspray method, which accompanies erosion and scouring. The final conclusions are summarized as follows. First, Straw-net+seedspray has difficulty recruiting plants to infertile weathered granite soil, which results in a lower coverage rate and fewer species, so it is not adequate construction method. Second, Vegetation spraying methods with wet media are more advantageous in early revegetation. The wet construction methods are faster than the dry construction methods in terms of early germination and its early growth are more excellent. Third, when constructing Vegetation spray methods with dry media, it were more advantageous if the thickness was thicker. When the soil-media is thicker, the soil is resilient to droughts, so the thickness must be flexibly applied according to the soil quality and slant of the weathered granite soil slope. The present study is a monitoring result for some areas of Gangwon-do, so its results may differ from other areas.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.103-110
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• 2006

When enforced earth is used for the retain wall and four walls, the most important thing would be how to maximize the land utilization. Accordingly, in case of enforced earth, we pile up the minimal height of earth$(20\sim30cm)$ and harden the earth using a static dynamic hardening machine. In this paper, we tried to analyze and. compare the stress transformation characteristics of reinforced weathered granite soil. with geosynthetics when repetitive load is added to the enforced earth structure and when static load is added. The purposes of the study are as follows; 1) To compare and analyze non reinforced weathered granite soil and reinforced weathered granite. soil by executing a unconsolidated-undrained triaxial compression tests. 2) To identify the strength characteristics of weathered granite soil reinforced with geotextile due to the repetitive dynamic loads through comparison of the stress due to the static load and the repetitive dynamic loads.

• Journal of the Korean GEO-environmental Society
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• v.5 no.1
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• pp.35-46
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• 2004

In Korea, around one - third of the country is occupied by granite, and granite weathered soils are widely distributed. Most of the research on this soil has been performed using reconstituted specimens because of the extreme difficulty of undisturbed sampling due to the sensitive particle structures. Therefore, the comparisons of deformational characteristics, which is expressed in terms of shear and Young's moduli and damping ratio, obtained from the undisturbed and reconstituted specimens are important for the reliable understanding of soil behavior. In this study, the resonant column and torsional shear tests were performed on granite weathered soils in Korea, and the deformation characteristics of undisturbed and reconstituted soil on granite weathered soils were evaluated and compared.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.3
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• pp.1-7
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• 2000

The aim of the work described in this paper is to study the shear characteristics of the weathered granite soil. To this end, a series of consolidated undrained triaxial compression tests are carried out to investigate the shear parameters-cohesion and internal friction angle for the degree of saturation and degree of weathering. From the results, it is found that the shear parameters of weathered granite soil are influenced on the degree of saturation, degree of weathering and disturbance. Especially, internal friction angle is more influenced on the upper factors than cohesion. And shear parameters are more acted on the degree of saturation than the degree of weathering in the test range. It is, therefore, recommended that must be considered the conditions of granite soil-degree of saturation, degree of weathering and disturbance etc-in case of the calculation of bearing capacity, stability analysis and other designs with shear parameters.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.37-47
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• 2005

The purpose of this study is to estimate the bearing capacity and settlement characteristics of the weathered granite masses, and on the process to achieve the purpose, in the first place, the weathered degree according to the absorption index was examined and reviewed, then plate bearings test in in-situ depth were tested, and finally the result was compared and examined with the result of the existing, estimate method and pressuremeter test. In order to achieve the purpose of this study, a typical area distributed with weathered granite masses, gyeonggi area, was chosen as a sample site for testing, and in the result, it appeared and found out that the more the weathered degree increases when the plate bearing test are tested, the more the bearing capacity decreases a numerical indexes and the more greatly the width of the decrease of bearing capacity increases around the boundary of specific, weathered degrees. Also, In the result from estimating the bearing capacity of weathered granite masses by the existing, suggested formula, it appeared that there is a tendency that the more the weathered degree increases, the more similar the bearing capacity becomes with the result of plate bearing tests.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.28-33
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• 2006

Shallow failures of slopes in weathered soils are caused by infiltration due to prolonged rainfall. These failures are mainly triggered by the deepening of the wetting band accompanied by a decrease in suction induced by the water infiltration. In this paper, hysteresis on soil-water characteristic curve(SWCC) of granite and gneiss weathered soils are investigated using transient flow analysis respectively. Each case was subjected to artificial rainfall intensities and time duration depending on the laboratory-based drying and wetting processes. The results show that the unsaturated seepage on weathered slopes are very much affected by the initial suction of soils and unsaturated permeability of the soils. In addition, a granite weathered soil has a lower air-entry value, residual matric suction, and wetting front suction and less hysteresis loop than a gneiss weathered soil.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.49-56
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• 1997

• Proceedings of the Korean Geotechical Society Conference
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• 1997.03a
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• pp.65-72
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• 1997

• Geomechanics and Engineering
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• v.22 no.2
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• pp.153-163
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• 2020

Laboratory experiments were conducted with two different soil conditions to investigate rainfall infiltration characteristics. The soil layer materials that were tested were weathered granite soil and weathered gneiss soil. Artificial rainfall of 80 mm/hr was reproduced through the use of a rainfall device, and the volumetric water content and matric suction were measured. In the case of the granite soil, the saturation velocity and the moving direction of the wetting front were fast and upward, respectively, whereas in the case of the weathered gneiss soil, the velocity and direction were slow and downward, respectively. Rainfall penetrated and saturated from the bottom to the top as the hydraulic conductivity of the granite soil was higher than the infiltration capacity of the artificial rainfall. In contrast, as the hydraulic conductivity of the gneiss soil was lower than the infiltration capacity of the rainfall, ponding occurred on the surface: part of the rainfall first infiltrated, with the remaining rainfall subsequently flowing out. The unsaturated hydraulic conductivity function of weathered soils was determined and analyzed with matric suction and the effective degree of saturation.