• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.786-793
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• 2021

Purpose: An experiment was conducted to analyze the characteristics of the settlement of soft clay soil in the central region of the west coast of Korea, which has a high silt content and is difficult to predict settlement due to various stress histories. Method: Field experiments were conducted for three cases. The settlement amount of the subsidence plate was measured in each case, and the following conclusions were drawn by analyzing Terzaghi's one-dimensional consolidation settlement amount, both the hyperbolic method and the Asaoka method. Result: The predicted value by Terzaghi was analyzed to be the largest in all cases, and it was predicted to be 111% to 187% larger than the subsidence plate settlement value. That is, the subsidence plate settlement value, which is the amount of settlement of the actual ground, showed a settlement of 53.4~89.9% compared to the predicted value of Terzaghi. Therefore, it was analyzed that the expected settlement of the Terzaghi method in the clay soft ground of the central west coast of Korea is more than the actual settlement. Conclusion: It was analyzed that the Asaoka method and the hyperbolic method presented relatively similar results, and in practice, predicting the settlement amount smaller than the actual settlement amount may cause a risk, so the hyperbola analysis method predicted 6~14% larger than the actual settlement amount can be used as a safety side.

• Journal of the Korean GEO-environmental Society
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• v.6 no.1
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• pp.53-62
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• 2005

This paper estimates the long-term settlement of Kimpo metropolitan landfill based on measured settlement data from 180 landfill monitors accumulated over a period of 12 years. Comparison of domestic and international settlement records indicate that the domestic compression rate is slightly lower due to greater portion of organic component. Several existing settlement models are used to compare with the observed behavior and also to estimate long-term settlement. The hyperbolic, Gibson & Lo, Bjarngard & Edgers and Power Creep Law models compare well with the measured settlement of the Kimpo metropolitan landfill. The settlement models are further used to estimate long-term settlement. Bjarngard & Edgers and Power Creep Law models result in higher estimates of the long-term settlement compared to the hyperbolic and Gibson & Lo models. Further comparisons indicate that other models, including Sowers and log models, are inapproriate for predicting the long-term settlement of the Kimpo metropolitan landfill.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.457-462
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• 2007

An application of concrete track is being activity processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance fee, but is very difficult to control the settlement of ground and embankment consisting of substructure of concrete track below the allowable settlement level. This is the reason why the measurement and evaluation of both ground and embankment settlement before the installation of the concrete track is very important. One ground, a lower subgrade, and five surface settlements are measured to understand the settlement behavior of ground and embankment settlement. The period to measure settlements was more than 1 year after the completion of embankment. In this test site, ground settlement was over during the construction of embankment, but the embankment settlement are being continuously proceeded after the completion of embankment. The settlement velocity gradually is slowing down as time goes by. This paper also analysed the reasons of abrupt settlement increase and concluded that the rainfall was one of the important reason to increase settlement rate.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.23-34
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• 2006

In this study, the centrifugal tests were performed to evaluate the behavior of reinforced retaining wall that allows the settlement of reinforcement strip. To analyze the stability of reinforced retaining wall, which drives the settlement of reinforcement strip, the results were compared with the conventional reinforced retaining wall. In the centrifugal tests, the aluminum plate for the face was used and the aluminum foil was used as a reinforcement. The decomposed granite soil was adopted as a backfill. As a result, the settlement free reinforced retaining wall reached to the failure at 80g-level. In contrast, the conventional reinforced retaining wall was collapsed at 69g-level. It means that the settlement free reinforced retaining wall has the stronger stability than the conventional reinforced retaining wall. Also, vertical earth pressure of the settlement free reinforced retaining wall near the base of wall was higher 16% than that of the conventional reinforced retaining wall.

• Journal of the Society of Disaster Information
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• v.18 no.4
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• pp.706-712
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• 2022

Purpose: In this study, field experimental research was conducted to analyze the settlement characteristics of soft ground in the central inland region of Korea and use it in practice. Method: The design predicted values and comparative analysis were performed using the ten settlement measurement data actually measured in the field experiment. For the design prediction value, Terzaghi's one-dimensional consolidation settlement analysis was used. In the experiment, the surface subsidence plate was used for field measurement. Result: The settlement behavior of the predicted value and the actual value was generally similar, but in the settlement value, the actual settlement value showed a settlement behavior of 30% or less compared to the predicted settlement value. The rate of consolidation settlement in this study area was in the range of 9.6% to 27.0%, and the average value was 18.21%. It is analyzed that the prediction of the settlement amount of the silty soils distributed in the inland plains of the central region of Korea can be relatively overestimated. Conclusion: It is judged that precise ground investigation and detailed prediction are necessary because there is a possibility of over-design in the design for predicting the amount of settlement of the silty soils distributed in the inland plains of the central region of Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.83-91
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• 2017

In case of estimation of settlement for the piled-raft foundation, it is necessary to consider interaction among raft, piles and soil. But, simple analytic methods usually are not applicable to considering this complicated interaction. In this study, a computer-based approximate analytic method, HDPR, was developed in consideration of above mentioned interaction in order to analysis of settlement for the piled-raft foundation. The finite element method was applied to raft analysis by means of the Mindlin plate theory, and soil and piles were modeled as springs which were connected with their raft. The linear spring which can consider multi layered soil and the non-linear spring were applied to soil springs and pile springs, respectively. The raft-piles-soil interaction was reflected to each spring. In order to verify the developed analytic method, it was compared and analyzed with 3D FEM analysis, existing approximate analytic method and site monitoring data. As a result, the developed analytic method showed reasonable results of settlement estimations of raft and piles for each case. From a practical point of view, it is confirmed that this analytic method is able to apply for analysis and design of the piled-raft foundation.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.13-19
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• 2011

Precast culvert system is generally constructed with a series of process such as excavation, ground mitigation, placement of culverts, anti-leakage packing between adjacent culverts, post-tensioning for PS strands and backfilling. In this process inappropriate ground mitigation often causes differential settlement and, correspondingly, makes water-leakage to be occurred between adjacent boxes. This study was performed to understand the behavioral characteristics of recently proposed precast foundation plate to support precast culvert system through on-site pilot construction. The gap between two adjacent culverts, increment of earth pressure at the bottom of culvert, vertical settlement of top of the culverts were monitored using various sensors. The monitoring results showed that the proposed foundation plate provides better culvert system in the points of less gap development, earth pressure and settlement at the adjacent of two culverts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5939-5946
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• 2013

The bridge approach slabs (BAS) to provide a transitional roadway between a roadway pavement and a bridge structure have not performed adequately due to various factors. The current Korean Roadway Design Guidelines treat the BAS as a simply supported beam with 70% of the span length and do not consider settlement and void development underneath the slab. To investigate the effect of soil settlements on the bending moment of BAS, a beam on elastic support (BAS-ES) was used in the present study. The parameters used in this study were span length, washout length, washout location, and soil modulus. It was shown from the parametric study that washout regions closer to the midspan exhibit maximum moment in the slab. Since voids under the BAS have typically been observed to be closer to bridge abutments, the springs from the abutment were removed to simulate settlement and void development in the model. The design moments based on AASHTO LRFD Bridge Design Specifications were compared to those of Korean Standard Specifications for Highway Bridge and Design Trucks for Highway Bridges. Even if the design moment from BAS-ES was used to incorporate the effect of the potential washout, significant savings could still be achieved compared to the current BAS design.

• Journal of the Korean Geotechnical Society
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• v.24 no.7
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• pp.37-42
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• 2008

This paper estimates the long-term settlement of Incheon unsanitary solid waste landfill, which is 20 years old. The unsanitary solid waste landfill was subjected to pre-loading system over a period of 1 year, and 300 settlement monitoring provided the long term settlement data. This landfill contains relatively small amount of organic component, and therefore the initial stage of settlement was very small. The existing settlement models were examineed by comparing the observed behaviors of this site, and also they were used to predict the long-term settlement. Power Creep Law (PCL) model showed good agreement with the measured settlement obtained from the initial stage of the measurement, but other models showed satisfactory agreements after $50{\sim}70$ days of measurement.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.53-66
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• 2007

A series of model tests were performed to investigate the soil arching effect in embankments supported by piles with geosynthetics. In the model tests, model piles with isolated cap were inserted through the holes in a steel plate, which could be operated up and down. Then geosynthetics was laid on the pile caps below sand fills. The settlement of soft ground was simulated by lowering the plate. As the plate was lowered, the soil arching was mobilized in the embankments. The deformation of both the sand fills and geosynthetics were captured by camera. Also the loads acting on pile cap and the tensile strain of geosynthetics were monitored by data logging system. Model tests showed that the embankment loads transferred on pile cap by soil arching Increased rapidly with settlement of the soft ground. In case of the absence of geosynthetics, the loads acting on pile caps dropped to residual value after peak value, whereas loads on pile caps gradually increased until constant value in case of geosynthetic-reinforced. This illustrated that reinforcing with the geosynthetics has a good effect to restrain the settlement of embankments. Also, the deformation shape of geosynthetics between pile caps was circular. The embankment loads transferred on pile caps can be estimated by considering both soil arching and tensile strain of geosynthetics in embankments supported by piles with geosynthetics.