• Journal of the Korean Geotechnical Society
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• v.28 no.8
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• pp.89-99
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• 2012

The expansion of a road on soft ground could induce an additional settlement to the existing road because of the consolidation characteristics of the soft soil layer subjected to additional load by an adjacent banking. In such case, the existing road could be faced with various problems during the stages of the construction and maintenance, such as deterioration of not only the surface smoothness yielding the decrease in automobile performance safety but also the structural stability of the embankment. These kinds of problems are expected to occur more freguently especially for the deep ground level with a fairly thick soft soil layer. Therefore, they should be examined and studied adequately during the design stage. As a reference case study, this paper deals with the project named Namhae Expressway of 2nd Branch with the soft soil layer with the thickness upto about 50m. After a lengthy review of the original design, an improved design is proposed.

• Journal of the Korean Geosynthetics Society
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• v.6 no.1
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• pp.1-7
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• 2007

In order to improve the bearing capacity of soft ground for the purpose of getting a trafficability of construction vehicles, the geosynthetics-sandmat system has often been used. Yamanouchi had proposed the equation of calculating the bearing capacity about this kind of bearing mechanism, which has a soft ground-geosynthetics-sandmat system. The bearing capacity equation by Yamanouchi has been widely using in our country. However this equation includes an important contradictory concept because if the contact width of vehicles is incresed to reduce the contact pressure, the bearing capacity is decresed on the contray according to this equation. In order to investigate this contradictory concept, the bearing capacity test has been performed on the soft model ground with geosynthetics-sandmat system. From the test results about various kinds of models, the principle that explain the contradictory concept has been found and on the basis of this principle the new bering capacity equation has been proposed by modifying Yamanouchi equation.

• Geotechnical Engineering
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• v.14 no.1
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• pp.81-92
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• 1998

Coal ash from thermal power plants has been produced in large quantity and discarded uselessly, However, it is possible to supply construction material properly by utilizing the coal ash as construction material. In this study, the applicable model and its applicability for deformation analysis of coal ash fill and reclamation ground are studied. Camflay model gives complete constitutive law which illustrates deformation and pore water pressure while soil is loaded under the various stresses at drained and undrained conditions. The merit of proposed model which is acquired from laboratory tests is that only a few soil parameters are available. The whole parameters of Camflay model are obtained by typical mechanical test and CV triaxial test on the sample with optimum mixing ratio( i.e. fly ash : bottom ash=5:5) Then the results from proposed numerical analysis are compared with laboratory results. The differences between laboratory test and numerical analysis are negligible. Parameters deter mined from laboratory tests are useful as a basic data for deformation analysis of coal ash reclamation ground using Camflay model.

• Journal of the Korean Geosynthetics Society
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• v.22 no.4
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• pp.9-15
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• 2023

Compaction is performed in civil engineering sites to secure the stability of the ground and prevent settlement. While the process of compaction is crucial, it is also essential to evaluate the degree of compaction after the completion of the process. In domestic sites, the evaluation of compaction is mainly conducted on a small number of spot using point-based tests such as plate load tests and sand cone tests. The methods presented so far allow assessment of surface compaction, but evaluating compaction in deeper layers poses challenges. Moreover, due to the limited coverage of point-based testing, it is difficult to achieve an overall assessment of compaction. As a solution to these issues, the Spectral-Analysis-of-Surface-Waves (SASW) tests were utilized to evaluate compaction. SASW tests offer a broader measurement range compared to point-based tests, and depending on the test setup, this method can provide the stiffness of the ground at greater depths. In this study, SASW tests were conducted in a compacted soil site under different conditions to assess compaction. Additionally, Nuclear Density Gauge tests were conducted concurrently to compare and verify the results of SASW. The research results confirmed the feasibility of evaluating compaction using SASW at the geotechnical site.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.23-34
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• 2006

In a oo dam at oo city of Gyeongbuk, severe damages have been occurred on lower part of dam due to heavy rainfall for several years. This caused significant impediment for maintaining its original function. This is considered as an excellent case for overall improvement of stability of dam system through successful investigation and construction work. This paper present comprehensive specifications that are generalized and used for securing stability of dams by quoting this example.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.2
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• pp.92-103
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• 1999

A series of field tests were performed to suggest a rational method for the stability evaluation of soft clay. The behavior of settlement-displacement obtained by field monitoring system was used to compare and analyze with various stability evaluation methods, and to investigate the applicability of the methods for stability evaluation of soft clay. The limit equilibrium method, numerical analysis and field monitoring methods were used to analyze the stability evaluation. The horizontal displacement was abruptly increased when physicla properties of soft clay reached its maximum values and therefore, the values of these properties could be used to the fundamental data for stability evaluation. The evaluation of the stability of clay embankment was suggested to use inclination of ccrve rather than critical line, and the minimum satey factor of 1.2 or larger for natural clay was recommeded . Therefore, the evaluation of short term stability of soft clay could be effectively peformed with the hypefrbolic model and the field monitored data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.665-670
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• 2006

In this paper, the results of empirical methods and the numerical analysis were compared and investigated on the lateral displacement due to embankment in soft soil. The empirical methods gave different results so the possibility of lateral displacement could not be determined only by the empirical methods. The numerical analysis could be used so effectively that its result showed useful lateral and vertical displacements with depth and distance.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.679-686
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• 2010

Mechanical characteristics of bottom ash produced in coal-fired power plant are investigated to utilize as light-weight fill materials. Triaxial compression test, water retention test, and unsaturated direct shear test were conducted for weathered soil (WS), reclaimed bottom ash (RBA), and screened bottom ash (BA). RBA had larger frictional angle and lower effective cohesion than those of WS. Water retention charactersitics of RBA and BA existed within distributions of soil-water characteristic curves for domestic weathered soils. Unsaturated shear strength of RBA was similar to that of WS at matric suctions of 50 kPa and 100 kPa. As a conclusion, bottom ash can be used as fill materials to replace the conventional construction materials by.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1212-1221
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• 2010

A theoretical equation was proposed to consider the effect of fill and ponding for the excess pore water pressure in agricultural reservoir on soft clay ground. For the purpose of verification of the proposed equation, laboratory model tests and field tests were performed and excess pore water pressure was compared to those predicted with the Terzaghi's method. The degree of consolidation according to ponding predicted by applying the proposed equation was close to the observed degree of consolidation on the double drainage condition(at DP-3) but it was less than the observed degree of consolidation on the single drainage condition(at DP-5). The predicted excess pore water pressure according to fill and ponding was very applicable to practice because it was close to the observed data.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.433-440
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• 2001

This study was to analyze characteristics of soils reinforced by FPF(Fibrillated Polypropylene Fiber). Laboratory test, model test and field tests were performed on soils reinforced by fibers, to evaluate the shear strength characteristics. For the silty sand, clayey sand and silty clay, the influence of fiber shape, fiber length and fiber content were evaluated from compaction test, direct shear test, uniaxial test, california bearing ratio(CBR) test. Fibrillated type fiber, 5cm long with a content of 0.5% shows 5∼30% increase of friction angle and 7∼55 percent increase of CBR value.