• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.492-497
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• 2008

The objective of this research is an investigation of engineering properties of weathered granite soil mixed with Phosphogypsum and recycled EPS beads as an light-weighted soil. A series of geotechnical laboratory tests including physical index test, compaction test, CBR test and direct shear test were performed for various mixing ratios. Based on the laboratory test results, it was found that the maximum dry unit weight of the light weight soil ranges $1.46{\sim}1.61g/cm^3$ and the maximum dry unit weight decreases about 11~19.3% with the increase of amount of the recycled EPS beads and the optimum moisture content increase. Since the CBR values of the light weight soil ranges 10.4~18.4%, the light weight soil mixed with Phosphogypsum and recycled EPS beads can be used as a light weight backfill material on the soft soil.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.43-50
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• 2000

This paper presents the engineering property of light weight soil made of soil mixed with recycled stylofoam and stabilizer. Recycled stylofoam beads is able to use by lightweight fill materials because it is light, adiabatic, and effective for vibration interception. Especially, recycled stylofoam beads is easy to supply because stylofoam have been recycle item in 1996. In this study, physical and geotechnical properties of the light weight mixed soil(weathered granite soil mixed with Stylofoam Beads) were analyzed by laboratory experiments to examine its suitability for backfill materials. Laboratory tests were performed to evaluated strength, bearing capacity, weight, permeability, microphotograph analysis with variation of mixing ratio. Based on the results, it is concluded that the use of recycled stylofoam beads is acceptable lightweight fill.

• The Journal of the Petrological Society of Korea
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• v.17 no.3
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• pp.133-143
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• 2008

On the basis of chemical composition of granite, gneiss and their weathering products, in this paper, rare earth elements (REEs) was estimated as tracer for clarifying a geochemical variance of earth surface material during weathering process. The chemical composition of clay, clay ware and pottery also were measured for testifying usefulness of REE geochemistry in clarifying the source material of pottery. It was observed that there was no systematic variation of chemical composition among source rock, weathered rock and soil during weathering process. The chemical composition of clay, clay ware and pottery also did not show systematic variation by baking pottery. However, PAAS (Post Archean Australian Shale)-normalized REE patterns of rock-weathered rock-soil and clay-clay ware-pottery are similar regardless of weathering process or ceramic art. Our results confirm that REE geochemistry is powerful tool for clarifying the source materials of surface sediment or archaeological ceramic products.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.17-26
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• 2005

Soil water characteristic curve (SWCC) is a unique characteristic that should be considered In the analysis of unsaturated soil and prediction of unsaturated properties. However, the volume change of soil specimens that happens in the existing apparatus affects the SWCC, Therefore, In this study, we intended to obtain more appropriate SWCC by measuring the change In the volume of the specimen in the SWCC tests. The measured change of void ratio indicates that the saturation step prior to the test changes the original structure of the soil specimen. Thus we carried out the test far the same specimen omitting the saturation step prior to the test. The change of void ratio by this test procedure is relatively small.

• Journal of the Korean Geotechnical Society
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• v.29 no.2
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• pp.57-64
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• 2013

In this paper, in order to solve high water content of water sludge and promote its recycle, sludge mixtures with various mixing ratios were produced. Sludge mixture consisted of water sludge and weathered granite soil. Their physical properties and unsaturated characteristics (soil-water characteristic curve, and unsaturated permeability function) were investigated by laboratory tests. Experimental test results indicated that at a given matric suction volumetric water content of sludge mixture increased as water sludge content increased. Air entry values of sludge mixture increased from 0.9 kPa to 2.4 kPa with an increase in water sludge content or fine content. In addition, unsaturated permeability function, which is an important factor for performing infiltration analysis, was predicted using saturated permeability and soil-water characteristic curve of sludge mixture.

• Journal of the Korean earth science society
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• v.26 no.7
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• pp.661-667
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• 2005

It was preliminarily considered that Jangdo wetland was a concave landform formed by the weathering of granite intruding Precambrian silicified metasedimentary rocks. Various granite-weathered topography was observed. The formation scenario of Jangdo wetland is as follows. By flood or slope mass movement of regolith, rock fragments were moved to form a low-relief slope landform. As a result, wetland was formed. By analyzing the slope soil and wetland sediment, we conjectured that Jangdo wetland depended on the influence of peripheral slope soil. In these concavelandform environment, the supply of water and organic materials was sustained for a long time to form a organicnondegradable wetland environment. In addition, the plants appropriate to this wetland environment were settled to thicken the wetland. This is how the present Jangdo wetland was thought to be formed.

• Journal of the Korean association of regional geographers
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• v.9 no.4
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• pp.534-545
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• 2003

The main purpose of this paper is to describe the granitic regolith and frost creep phenomena in Daegwanryung area in order to demonstrate the relationship of the weathered materials and the surrounding surface, in order to point out that the characteristics of this particular complex of granitic regolith most closely resemble those of soil frost creep phenomena formed elsewhere under periglacial conditions. For this study, the writer has clarified their structure and its associated milieux, with a group of methods and techniques, field survey, micro-morphological analysis, granulometry of weathered materials etc. Such facies of granitic regolith in situ with silty heterometric materials and micas are prone to be deformed by cryo-suction as well as deep freezing. It was probably formed by cryogenic activity, or frost creep in the periglacial climate of a very cold and humid condition.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.451-458
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• 2001

The purpose of this study was to evaluate shear parameters on cutting slope of weathered granite soils by using small dynamic cone penetration test on the very moment of its cutting. The results were : On the relations among N$\_$c/, Li, and CEC, the condition of Li＞6%, CEC＞14(meq/100g) corresponds to that of N$\_$c/ values of 2∼30, and 3＜CEC＜14(meq/100g) to N$\_$c/=30∼50. Comparing the smallest penetration depth from two small dynamic cone penetration tests done at 5m below from the top of the slope on April 15th, October 31t. there was a l0cm difference. So we could find out the degree of weathering on the slope. And dividing the difference by 190 days (the whole testing time), we could know it's being weathered 0.052mm each day. The more N. value increases, the more shear parameters(internal friction angle ; $\phi$, cohesion : c) increase at a standard pressure($\sigma$＞32㎪). So the condition of N$\_$c/=2∼50 corresponds to that of $\phi$=27∼50, c=12∼49㎪. From the above testing results, the N$\_$c/ values more correspond to $\phi$ values than c values. In conclusion, this study suggests that on small dynamic cone penetration test a penetration boundary line of 5 centimeters is decided at around Li=4%, CEC=3(meq/100g) which is classified as a strong weathering soil. It also shows that as Li increases CEC increases as well, while N$\_$c/ decreases.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.323-334
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• 2000

This study was carried out to investigate the effects of geological and topographical features on landslide and land-creep at the twenty four surveyed sites of Kyungpook province. According to the results obtained, it was concluded that continuous heavy rainfall was one of the primary factors to occur landslide and land-creep. Most of the landslides occurred in the past were concentrated in the granite and granitic gneiss zones, while land-creeps were mainly occurred in the mud-stone zones. Therefore, it was thought that the physical properties such as soil texture, solid phase, moisture contents, density, hardness and porosity rate of weathered granite and granitic gneiss could affect the occurrence of landslide and land-creep. Due to the holding of sand contents in the upper soil layers of weathered granite and granitic gneiss, rainfall could infiltrate into the soil easily. While lower soil layers contained much quantity of clay and silt contents, those soils saturated with rainfall cause to lose viscosity and shear strength. Therefore, it was seemed that landslide was occurred more easily and the saturation of those soils was made much easily by bed rocks under those soils. Landslide and land-creep are slided into lower place by gravitation and slope degree factors. Therefore, prediction of landslide occurrence is very difficult because landslide is occurred abruptly, and physical properties of the soil have to be understood and checking the existence of bed rocks under the soils is not easy, on the other hand, land-creep is progressed very slowly. Therefore, it was suggested that in a degree creeping could be protected by removing of several causing factors.

• Journal of the Korean Geotechnical Society
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• v.33 no.1
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• pp.57-65
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• 2017

During a construction of embankment, sub base, or retaining wall backfill, the speedy measurement of water content is necessary. In this study, a test method for field determination of water content of soil by the calcium carbide gas pressure (speedy water content measurement method) was evaluated for its reliability and accuracy. Dry oven and microwave oven methods were also used for water content measurement. In the test, weathered granite and Nakdong River sand in the site and kaolinite were used for water content measurement. The mass of 20, 22, 24, 26, 28, and 30 g of soil was respectively tested for 1, 3, and 5 min. The effect of each sample on water content was compared one another and analyzed. As the mass and testing time increased, the water content increased. The amount of soil was more important factor than testing time for the speedy water content measurement. In order to obtain similar result to that of dry oven method, 3 min of testing time with 24 g of soil was necessary for weathered granite classified as SM and 3 min with 30 g for Nakdong River sand classified as SP. For Nakdong River sand with 20-50% of kaolinite, the water content by speedy measurement increased as the clay content increased.