• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.713-716
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• 2008

In about the concrete application which recycles Ash the research came to be advanced as research in compliance with researchers relation actively in about cement substitutional concrete mixing ratio and burglar quality of existing. The research which it sees as fundamental research the research which it follows in cement substitutional concrete mixing ratio of existing and it researched different Bottom-Ash recycling qualities in about cup aggregate partial substitution Bottom-Ash application.

• Journal of the Korean GEO-environmental Society
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• v.3 no.2
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• pp.49-60
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• 2002

A study on mineral composition and chemical component governing of weathering process is necessary to know the weathering characteristics of sedimentary rocks. In this study, a mineral and chemical component analysis, and physical and engineering characteristic tests were conducted to find out the characteristics of sedimentary rocks in Daegu, according to the weathering degree of sedimentary rock. Test results show that the mineral composition of rock, such as Albite (Ab), Muscovite (Ms), Magenetite (Mt) and the chemical composition of $A_2O_3$, CaO, $Na_2O$, $K_2O$, MgO and so on are closely related to the weathering. Based on the test results, we illustrated the quantitative application of weathering decision for the sedimentary rocks.

• The Journal of Engineering Geology
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• v.14 no.4 s.41
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• pp.371-379
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• 2004

Soil investigation data at 7 different locations around Honam costal region were analyzed and experimental correlations between soil properties and parameters of soft clay were presented. Most soils were classified as CL and CH by the Unified Soil Classification System and were unstable structurally because the water contents were generally greater than the liquid limits. The compression index has good correlations with water content, liquid limit and initial void ratio. The trend of these correlations were similar to the Skempton equation Cc = 0.009(LL -10) and other studies for Korean soft clays but the constants were small different. The slope of these correlations for Honam costal region were slightly greater than those for Kyunggi costal region and Kyungnam costal region. The correlation coefficient (R) between the liquid limit and the plastic index is 0.93. It is seen that not only the water content and the liquid limit but also the water content and the initial void ratio are correlate, therefore the experimental equations were presented for the practical purpose.

• Journal of the Korean Geosynthetics Society
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• v.23 no.1
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• pp.39-47
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• 2024

In this study, physical property tests and standard consolidation tests were conducted on the marine clay of Busan New Port and North Port, the middle and lower reaches of the Nakdong River including Gimhae and Yangsan, and Ulsan regions. The moisture content, a property unrelated to sample disturbance with small individual test errors, was used for regression analysis with the compression index, virgin compression index, consolidation coefficient, expansion index, and secondary compression index, among others. Subsequently, the correlation and accuracy were evaluated. Upon analyzing the correlation between the moisture content, void ratio, and liquid limit commonly used physical properties for calculating compression indexes, it was confirmed that the liquid limit had the lowest correlation. Through a linear regression analysis of the consolidation constants using the current moisture content in the natural state, a high correlation was demonstrated. Relationship equations were then presented to determine settlement and settlement time. This study suggests that moisture content can be utilized as an alternative for evaluating and calculating consolidation constants when examining ground settlement in sedimentary clays distributed in the Busan and Gyeongnam regions.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.15-26
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• 2007

Los Angeles abrasion loss test has usally been applied to the quarry for the purpose of aggregate hardness estimation. 324 blocks from 25 sites of Kyeongsang basin samples of sedimentary rock were examined and tested in laboratary. This paper found that L. A. abrasion loss test is a good method to estimate engineering index such as uniaxial compressive strength, elastic modulus, indirect tensile strength, point load strength index, Schmidt hammer rebound value of sedimentary rocks with high correlation factor. Engineers will prefer L. A. abrasion loss test to the other one for design and construction as this method is quick and easy.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.195-203
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• 2016

Concrete slab track was applied to the Gyeoungbu High Speed Railroad step 2 and the Honam High Speed Railroad. Concrete slab track incurs higher construction cost and lower maintenance cost than existing gravel track. For these reasons, the use of concrete slab track has increased in Korea. The biggest problem in the use of concrete slab track is repairing damage from settlement that can occur while trains are in service. High speed railroad design standards require allowable residual settlement of concrete slab track of less than 25mm. In order to satisfy the requirement of long term stability of concrete slab track, it is necessary to manage the secondary compression settlement within the allowable residual settlement. This study is to evaluate the secondary compression settlement with the variation of the secondary compression index, thickness of soft ground, and concrete slab track life. Statistical analysis is performed to determine the probability of distribution of areas where serious problems will be caused after the concrete slab track is constructed.

• Journal of the Korean GEO-environmental Society
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• v.2 no.1
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• pp.23-30
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• 2001

A Series of laboratory tests were conducted to investigate the engineering characteristics for organic soil widely distributed in Yong-dong region which always makes problems in construction works. Physical characteristics of Yong-dong organic soil area were measured in terms of such categories as nature water content, organic content, specific gravity, liquid limit, and plasticity index. As a result, it was found that nature water content was $50.8^{\circ}-343.5%$, organic content 12.1-42.5%, specific gravity 1.76-2.71, liquid limit 46.6-440.2%, and plasticity index 9.2-557.2%. Also, as consolidation load increases, consolidation coefficient slightly decreases with small up and down. The ratio of secondary consolidation coefficient to compression index is 0.001-0.091 $C_a/C_c$, secondary coefficient tends to increase greatly when organic content is in the range of 11-22%.

• Composites Research
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• v.37 no.1
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• pp.46-52
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• 2024

The development of transportation methods has improved human transportation convenience and made it possible to expand the travel radius of people with disabilities who have difficulty moving. However, in the case of WAV (wheelchair Accessible Vehicle), the safety that may occur in a vehicle accident is still lower than that of regular passenger seats. In particular, in the case of a rear-end collision that may occur in a defenseless situation, it can cause fatal neck injuries to disabled passengers. Therefore, a more detailed design plan must be reflected in the headrest to be applied to WAV. In this study, a multi-cell headrest was proposed to implement local compression characteristic distribution of the headrest during rear-end collision of WAV. Afterwards, a correlation analysis was performed between the passenger's NIC (Neck Injury Criterion) and impact energy absorption using the data set construction through analysis and the clustering results using k-means clustering. As a result of clustering, it was confirmed that data clusters with similar characteristics were formed, and a correlation analysis between NIC and impact energy absorption through the characteristics of each cluster was performed. As a result of the analysis, it was confirmed that the softer the cell compression characteristics in Mid3 and Mid6, the more impact energy absorption increases, and the harder the cell compression characteristics in Front2, Mid3, and Mid6, the more effective it is in reducing NIC.

• Geotechnical Engineering
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• v.14 no.4
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• pp.47-60
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• 1998

A series of conventional tests and CRS consolidation tests with different rates of strain were performed to investigate the consolidation characteristics of marine clay. Preconsolidation pressures were evaluated by applying previously proposed methods for both the conventional tests and CRS tests results in order to check the legitimacy of those methods. The effects of strain rate on effective consolidation stress strain relationship, porewater pressure, and preconsolidation pressure were also discussed It was found that the effective stress strain relationship and the preconsolidation pressure are a function of strain rate imposed during consolidation test, but compression index isn't. The preconsolidation pressure ratio ($a_2=\sigma'_{pCRS}/\sigma'_{pConv}$)of marine clay appears proportional to the logarithm of strain rate, with average values ranging from 1.11 to 1.30 for strain rates between $1\timesx10^{-4} %/sec\; and\; 4\times10 %/sec$. The porewater pressure ratio during CRS teats does not exceed 6.0% except when the strain rate is $6.67\times10^{-4} %/sec$. Coefficient of consolidation or coefficient of permeability at normally consolidated range was not affected by the type of consolidation tests and the strain rate. Typical values of compression index (C.), coefficient of consolidation(c.), and coefficient of permeability (k.) at normally consolidated range were 0.56-0.95, $0.56\times10^{-4}~3.0\times10^{-4}cm2/sec,\; and\; 2.0\times10^{-8}~7.0\time10^{-4}cm/sec,$ respectively.

• Geotechnical Engineering
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• v.9 no.3
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• pp.5-22
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• 1993

A series of laboratory tests (physical and mechanical index and engineering design) were conducted on undisturbed granite soils of CW and RS weathering grades in Korea. From these testes it can be concluded that most of physical and mechanical index values are very sensitive to change in weathering grade from CW to RS. Engineering design tests indicate that the unconfined compressive strength and the shear strength parameters are significantly reduced and that the soil becomes ductile and plastic with increasing weathering and saturation. It was found that weathered granite soils have the special characteristics when water saturated: (i) they significantly lose their shear strength(especially cohesion) and unconfined compressive strength, (ii) they are fragile and their grains break down in water as observed in grain size analysis.