• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.219-226
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• 2004

We measure subsidences occurred in a reclaimed coastal land, Noksan industrial complex, by using JERS-1 SAR (1996-1998) and RADARSAT-1 SAR (2002-2003) dataset. SAR with a high spatial resolution (about several or several tens meter) can reveal the two-dimensional distribution of settlement that would be bardly estimated from in situ measurements. The DInSAR results show significant deformation signal associated with soil consolidation. Accuracy of the settlements estimated by 2-pass differential interferometry (DInSAR) is evaluated using the measurements of settlement gauge. A two-dimensional subsidence map is constructed from 7 qualified pairs. Comparing the JERS-1 radar measurements with the ground truth data yields the correlation coefficient of 0.87 (RMSE of 1.44 cm). The regression line shows the gradient of 1.04 and intercepts close to the origin, which implies that the unbiased settlement can be measured by DInSAR technique. The residual settlements are also detected from RADARSAT-1 pairs. The extent and amount of the settlements are matched well with ground truth data.

• Geomechanics and Engineering
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• v.14 no.1
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• pp.43-50
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• 2018

Applicability of constructing piled raft foundations on soft clay has been given attention in recent years. Lack of sufficient stiffness for soil and thus excessive settlements to allow higher contribution of piles is the major concern in this regard. This paper presents a numerical investigation of performance of piled-raft foundations on soft clay with focusing on a case study. A 3D FEM numerical model is developed using ABAQUS. The model was calibrated by comparing physical and numerical modeling results of other researchers. Then the possibility of using piled-raft system in construction of foundation for a water storage tank in Sarbandar, Iran is assessed. Soil strength parameters in the numerical model were calibrated using the instrumentation data of a heavily instrumented preloading project at the construction site. The results indicate that choosing the proper combination of length and spacing for piles can lead to acceptable differential and total settlements while a high percentage of total bearing capacity of piles can be mobilized, which is an efficient solution for the project. Overall, the construction of piled-rafts on soft clays is promising as long as the total settlement of the structure is not imposing restrictions such as the common 25 mm allowable settlement. But instead, if higher allowable settlements are adopted, for example in the case of rigid steel tanks, the method shall be applicable with considerable cost savings.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.49-56
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• 2009

The quantity of the fuel gas consumed is trending upwards because it can be easily delivered but isn't deteriorated and doesn't have any environmental pollution. Though there are many advantages to use the fuel gas, it can be hesitated to consume more gas because of its explosiveness and combustibility. So paying more attentions to prevent the fuel gas accidents is required. In this paper, we examine the present situation data about the fuel gas accidents and analyze them statistically using ANOVA. we confirm that there is an acceptable difference between the mean values of accidents classified by the kind of gas, the cause, the type and the place but isn't by month. It is expected that our result can be applied as preliminary data when mapping out a strategy for preventing the fuel gas accidents.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1712-1716
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• 2008

Performance of ground improvement project using prefabricated vertical drains of condition, in which approximately 10m dredged fill overlies original soft foundation layer in the coastal area has been conducted. From field monitoring results, excessive ground settlement compared to predicted settlement in design stage developed during the following one year. In order to predict the final consolidation behavior, recalculation of consolidation settlements and back analysis using observed settlements were conducted. Field monitoring results of surface settlements were evaluated, and then corrected because large shear deformation was occurred by construction events in the early stages of consolidation. To predict the consolidation behavior, material functions and in-situ conditions from laboratory consolidation test were re-analyzed. Using these results, height of additional embankment is estimated to satisfy residual settlement limit and maintain an adequate ground elevation. The recalculated time-settlement curve has been compared to field monitoring results after additional surcharge was applied.

• Journal of the Korean housing association
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• v.22 no.2
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• pp.91-99
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• 2011

The purpose of this study is to clarify the transitional process of spatial configuration of 'Topdong Yangdalmal'; One of the existing 22 old settlements in cheongju city. The results are as follows. 1) Side roads are derived from Inner road until 1970, so large-scale lots are subdivided small-scale lots. The houses are mostly in 1970s and 1980s. The existing old houses are 11, their orientation are East South, and the entrance gives on side road. The orientation, court yard, and entrance of the houses nearby side roads keep ongoing, in spite of alteration and extension. Especially, Entrance is changed by the new arterial roads and subdivided lots, but, the houses nearby side roads are continued as in the past. 2) The newly built houses in 1970's are 20, and it's arrangements are equal to existing old one. The orientation of houses after 1980's is the same in 1970's. But, the entrance is changed by subdivided lots, and the size of the court yard are reduced or disappeared. In other hand, the houses as the same size of the existing houses, and Storyincrease continue court yard as in the past. Therefore, the houses which are nearby inner road, and increase story, are continued, in spite of the newly built one.

• Journal of Korean Society of Rural Planning
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• v.2 no.2
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• pp.67-80
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• 1996

Less Favored Area(LFA) is a newly shaped regional concept and just appearing as a new community design target, where the topogeographical, industry-locational condition and the daily living environment have been outstandingly inferior to any other regions. Community Design(CD) principles that cover a spatial order of settlements are introduced in this study when the CD concept is applied to the LFA. The study puts a great stress on the horizontal and vertical order of communal spatial units and living activities oriented to residents'socio-economic activities, on which a CD district and an inner spatial organization of community is based. Therefore the various relationships between residents' activities and particular places, such as that between agricultural production and land, access to living services and community-outer settlements, is analysed through the field study. The emphatic point is that the spatial unit and organization of community, namely settlement order is casted not only by the horizontal coverage but also by the vertical hierarchy forming a cubic-like spatial order. Applying the CD idea to LFA has limit because the CD has been oriented on urban architectural style and community participation process. Nevertheless, that has a new possibility to understand the fundamental and archetypical change of a spatial pattern of community uncovering the accumulated layer of settlement order especially in the drastically changed mountain community from past to now.

• Journal of Korean Society of Rural Planning
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• v.4 no.2
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• pp.41-57
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• 1998

Now, the conservation policy of historic environments in Korea which started in early 1980's, is in a danger. In addition, because of economic crisis started last year, the concerns for historic environments are growing weaker. However, this situation can be a good opportunity to prepare for the coming conservation works, The purpose of this study is to find clues for conservation of historic environments by considering foreign precedents. For concrete results, this study selects historic rural settlements as a case and focuses on the relationship among related people in the light of the their rights. Based on the consideration of foreign precedents, three different characters in the conservation process could be identified compared with korean cases; 1) Except partial works of public sector, generally the conservation process is under the control of nonprofit groups and residents themselves, 2) Conservation methods include with the proper change process for the sustainable settlement, and avoid the unconditional past-oriented approach, 3) Conservation methods are composed of not only the preservation of external forms such as assets but also the continuous participation and management of the community. And the most important clue which has been extracted is that the diverse rights of related people in the historic rural settlements should be kept in balance thoroughly.

• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.329-337
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• 1999

With the ready access to the high resolution satellite image data, users of and areas covered by satellite image data are constantly on the rise world-widely. Korea will also be able to take full advantage of the satellite data once the Korea Multi-Purpose Satellite 1 (KOMPSAT-l) is successfully launched. Harmonizing satellite data production and application technology and users' needs, along with the guiding policy is essential for promoting satellite data use. Up to now, the Korean government has mainly concentrated on developing production technology for the satellite instruments. However, the imminent task of independent satellite data production demands a promotion policy for satellite data use. In this context, the policy is defined as an important medium for identifying the role and status of satellite image information at the national level and also preparing the legal as well as systematic foundation for producing, building, distributing, and packaging satellite data. The present paper aims to examine the role and status of the satellite data as well as their current status and problems in Korea in reference to the National Spatial Data Infrastructure, and finally to provide the policy directions to promote the satellite data use in public sector on the basis of the preceding analyses.

• Geomechanics and Engineering
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• v.18 no.6
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• pp.575-584
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• 2019

The groundwater level (GWL) is an important subsoil condition for the design of foundation. GWL tends to fluctuate often with seasonal variation, which may cause unexpected, additional settlements with some reductions in the safety margin of foundation. In this study, the effects of fluctuating GWL on the load carrying and settlement behavior of footing were investigated and quantified. A series of model load tests were conducted for various GWL and soil conditions using a hydraulically-controlled chamber system. Changes in load level and rising and falling GWL fluctuation cycle were considered in the tests. Settlements during GWL rise were greater than those during GWL fall. The depth of the GWL influence zone ($\underline{d}_{w,inf}$) varied in the range of 0.3 to 1.5 times footing width and became shallower as GWL continued to fluctuate. Design equations for estimating GWL-induced settlements for footings were proposed. The GWL fluctuation cycle, load level and soil density were considered in the proposed method. Changes in settlement and factor of safety with GWL fluctuation were discussed.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.67-76
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• 2009

Statistical analysis was performed using a series of data on RMR, RMR* and crown settlements collected from sites of weathering rock tunnels in Korea. The crown settlements were predicted by recurrence analysis, exponential function, and artificial neural network (ANN) using collected in-situ data. The result of the prediction fitted well compared to the measured settlement in the order of ANN, exponential function, and recurrence analysis. The range of crown settlement predicted by recurrence analysis widely scattered and promised larger settlement than the measured. Also in all method, the predicted value by RMR well matched compared to the measured settlement predicted by RMR*.