• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1196-1202
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• 2007

In construction of high speed railway, the fan shape is limited to achieve reduction of required travel time and concrete railway which has structural stability and induces small maintenance cost with allowable ground settlement is recently applied. So construction of concrete railway on soft ground in which considerable ground settlement occurs increases and settlement management in soft ground section is required. Field monitoring on ground movement and integrated geotechnical information system which manages construction, design, and field monitoring data are essential for settlement management of concrete railway subgrade. Site investigation data are also required due to future repair work. Therefore in this study, integrated geotechnical information system for construction and maintenance of concrete railway is developed. The developed system consists of a database and an application program. The database contains site investigation, construction, design, and field monitoring data throughout a railway. Application program performs various functions on managing and utilizing information in the database with graphic visualization of output. And by providing integrating information with comprehensible visual displays, the applicability and effectiveness of the developed system for construction and maintenance management were confirmed.

• Journal of the Korean Geotechnical Society
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• v.20 no.4
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• pp.49-56
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• 2004

Tracer tests were conducted to investigate leachate outflow through damaged parts on HDPE liner subject to puncture loads in a closed landfill. Natural gradient tracer test was used with two different types of tracers, iodide and Rhodamine WT. Tracers were selected under careful consideration of chemical components of leachate. Five injection wells with fourteen detection points were installed and operated throughout the test site. In this study, it is found that Iodide and Rhodamine WT are applicable and effective for leachate leakage investigation on waste landfills. Also, it is concluded that considerable amount of leachate was leaked through the rain water drain box and side wall of drain box.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.603-610
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• 2007

It is well known that the standard penetration test (SPT) has been used in all over the world to get geotechnical properties of the ground. However, it is difficult to apply the SPT to the dense sand, gravel, weathered rock, etc. For the application of the SPT in these grounds, it is necessary to change in the diameter and the impact energy of the SPT. For the improvement of site investigation technology, Large Penetration Testing device (KICT-type LPT) was developed and applied to the in situ condition. The drop height and weight of the hammer in developed system were decided as 760 mm and 150 kg, respectively. Semi-auto hammer drop system identical with KS F2307 and JI A1259S was adopted. And the developed sampler has the inner diameter of 63 mm and the length of 500 mm with the adjustment of energy ratio to the SPT of 1.5. The hammer energy level was measured during the performance of the KICT-type LPT using SPI system (quality control system from driven piles).

• Geomechanics and Engineering
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• v.14 no.3
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• pp.271-281
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• 2018

A jointed rock slope stability evaluation was simulated by a discontinuous deformation analysis numerical method to investigate the process and safety factors for different crack distributions and different overloading situations. An optimized method using Discontinuous Deformation Analysis for Rock Failure (DDARF) is presented to perform numerical investigations on the jointed rock slope stability evaluation of the Dagangshan hydropower station. During the pre-processing of establishing the numerical model, an integrated software system including AutoCAD, Screen Capture, and Excel is adopted to facilitate the implementation of the numerical model with random joint network. These optimizations during the pre-processing stage of DDARF can remarkably improve the simulation efficiency, making it possible for complex model calculation. In the numerical investigations on the jointed rock slope stability evaluations using the optimized DDARF, three calculation schemes have been taken into account in the numerical model: (I) no joint; (II) two sets of regular parallel joints; and (III) multiple sets of random joints. This model is capable of replicating the entire processes including crack initiation, propagation, formation of shear zones, and local failures, and thus is able to provide constructive suggestions to supporting schemes for the slope. Meanwhile, the overloading numerical simulations under the same three schemes have also been performed. Overloading safety factors of the three schemes are 5.68, 2.42 and 1.39, respectively, which are obtained by analyzing the displacement evolutions of key monitoring points during overloading.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.4
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• pp.64-75
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• 2008

Since the current database systems for managing geotechnical investigation results were limited by being described boring test result in point feature, it has been trouble for using other GIS data. Although there are some studies for spatial characteristics of subsurface modeling, it is rather lack of being interoperable with GIS, considering geotechnical engineering facts. This is reason for difficulty of practical uses. In this study, we has developed subsurface spatial information model through extracting needed geotechnical engineering data from geotechnical information DB. The developed geotechnical information clustering program(GEOCL) has made a cluster of boring formation(and formation ratio), classification of layer, and strength characteristics of subsurface. The interpolation of boring data has been achieved through zonal kriging method in the consideration of spatial distribution of created cluster. Finally, we make a subsurface spatial information model to integrate with digital elevation model, and visualize 3-dimensional model by subsurface spatial information viewing program(SSIVIEW). We expect to strengthen application capacity of developed model in subsurface interpretation and foundation design of construction works.

• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.35-40
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• 2013

In most cases, Geotechnical Structures installed in freezing areas require extra countermeasures for reducing freeze damage. However, in terms of domestic tunnels, studies and case reports for geotechnical structures such as tunnels and retaining walls are not fluently carried out, causing lack of research about ways to decrease freeze damage. For these causes, domestic design criteria about structures does not specifically institutionalization for geotechnical structures. This research have done on-site investigation about tunnels, cut slopes and retaining walls. Also, this research includes the process of analyzing the histories of maintenance for class 1 and class 2 structures that happened in the past 40 years, studying characteristics of structure's maintenance and reinforcement in different areas with different climate. As the result, it was analyzed that domestic geotechnical structures showed need for longer maintenance and reinforcement that are located in Gangwon mountain area, Gangwon north region and Gyeonggi north region where the temperature is relatively low. This research can be concluded in need for revision of design criteria for structures located in freeze damage area.

• Geomechanics and Engineering
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• v.34 no.2
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• pp.155-171
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• 2023

Aiming at the grouting treatment of water inflow in karst conduits, a visualized experiment system for conduit-type grouting blocking was developed. Through the improved water supply system and grouting system, and the optimized multisource information monitoring system, the real-time observation of diffusion and deposition of slurry, and the data acquisition of pressure and velocity during the whole process of grouting were realized, which breaks through the problem that the monitoring element is easy to fail due to slurry adhesion in conventional test system. Based on the grouting experiments in static and flowing water, the diffusion and deposition behavior of the quick-setting slurry under different working conditions were analyzed. The temporal and spatial variation behavior of the pressure and velocity were studied, and the blocking mechanism of the grouting were further revealed. The results showed that: (1) Under the flowing water condition, the counter-flow diffusion distance of slurry was negatively correlated with the flow water velocity and the volume ratio of cement and sodium silicate (C-S ratio), and positively correlated with the grouting volume. The slurry deposition thickness was negatively correlated with the flowing water velocity, and positively correlated with the grouting volume and C-S ratio. (2) The pressure increased slowly before blocking of the flowing water and rapidly after blocking in karst conduits. (3) With the continuous progress of grouting, the flowing water velocity decreased slowly first, then significantly, and finally tended to be stable. According to the research results, some engineering recommendations were put forward for the grouting treatment of the conduit-type water inflow disaster, which has been successfully applied in the treatment project of the China Resources Cement (Pingnan) Limestone Mine. This study provided some guidance and reference for the parameter optimization of grouting for the treatment projects of water inflow in karst conduits.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.119-131
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• 2014

For quick and accurate ground investigation in wide construction site being not easy to access, advanced dynamic cone penetration test equipment was developed based on widely used equipment abroad. Advantages of existing equipment of portability and simple testing method were reflected in the new developed equipment. Meanwhile, by extending connection of lower rod, penetration depth is raised to 6m from 1 m of the existing equipment. Moreover, by assembly of hammer (2+3+3kg) and cone (3 types) etc., it is possible to perform test under the same conditions with those by German and Japan dynamic cone penetration test equipment (Tsukuba, PWRI and SH types). Auxiliary equipment was applied to make sure of perpendicularity as penetration depth increases. Applicability of the new developed equipment was evaluated through tests on various fields and its reliability was verified.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.57-65
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• 2006

In the Nakdong River estuary soft and thick clay, which called Pusan clay, are deposited. Despite a number of great reclaimed projects that have been performed in the area, the consolidation settlement and time have been significantly underestimated due dominantly to sample disturbance, since the last decade. In order to resolve the underestmation, it was necessary to examine the compressibility characteristics through a systematic geotechnical investigation on the clay. In this study an advanced sampling technique was adopted on two sites chosen along the coastline, and then oedometer testing and geological investigation were performed for the undisturbed and reconstituted samples. As the results, the compressibility parameters of the clay were representatively determined, as well as their correlation. Particularly the effects of depositional environment on the physical indexes, level of structure, sample disturbance and compressibility parameters were analyzed for the clay.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.5-16
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• 2007

The stone column method is widely used in Europe as an alternative to conventional pile foundations. Several benefits of using the stone column method include sound performance, low cost, expediency of construction, and liquefaction resistance among others. Recently, geosynthetic-encased stone column approach has been developed to improve its load carrying capacity through increasing confinement effect. Although such a concept has been successfully applied in practice, fundamentals of the method have not been fully explored. This paper presents the results of an investigation on the load carrying capacity of geogrid-encased stone column using a series of 2D finite element analyses. A parametric study was then conducted for influencing factors such as effect of geogrid encasement, encasement length, geogrid strength, among others. The results of the analyses indicated improved short- and long-term load carrying capacity of the geogrid-encased stone column method has advantages over the conventional stone column method without encasing.