• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.131-139
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• 2004

When calculating bearing capacity and settlement of actual foundation from plate test result fur design and construction of shallow foundation, scale effect should be considered. But, adequate guide and test result of scale effect were not prepared yet in Korea. So, to analyze the relations of bearing capacity and settlement as the difference of loading plate sizes, model test and field loading test were performed with different loading plate on weathered-granite layer. Model tests were conducted with water content, compaction number, saturated unit weight and plate size(Dl5, 25cm) in soil-box$(2,000\times 2,000\times 1,000mm)$ formed soil layer. Field loading tests were carried out with diameters of loading plate$(D15, 25, 30, 40, 75\times 75, 140\times 210cm)$ on the same soil condition. Finally, we presented the prediction formula of bearing and settlement for computating scale offset in design of shallow foundation through result analysis of load test and numerical simulation on weathered soil and rock.

• Geomechanics and Engineering
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• v.33 no.1
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• pp.91-99
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• 2023

To test the effect of various pile tip shape series of model scale loading tests were carried out on test piles with special pile tips. Special pile tips were made using the 3D printer and were attached to the bottom end of the test pile for loading tests. The pile tips were made to have 30°, 45°, 60° inclined tips, as well as a rounded tip. The main objective of the test was to observe the effect of various pile tip shapes on settlement and penetrability of the pile. Moreover, a numerical model simulating the pile loading test carried out in this study was established and verified based on the loading test results. From this, the stress concentration around the pile tip was investigated. This will allow us to analyze the decrease of stress concentration around the pile tip which is the main cause of the pile tip damage during pile installation. However, modifying the pile tip shape will eventually increase the settlement of the pile. By estimating the degree of increase in pile settlement, the viability and the efficiency of the pile shape modification was judged. In addition, case studies on the effect of different pile tip shape and ground conditions on pile settlement and stress dispersion was conducted.

• Geomechanics and Engineering
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• v.39 no.2
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• pp.197-209
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• 2024

This paper investigated the deformation of a large-diameter pipeline caused by double shield tunnel construction in silty fine sand strata in Nantong, China, by on-site measurements and numerical simulations. Results indicate the pipe settlement curve was not symmetrical after the double tunnel construction in the silty fine sand strata. The construction of the subsequent tunnel had a significantly smaller impact on the stress and horizontal displacement of the pipeline than the preceding tunnel. There is a significant shading effect of the large-diameter pipeline, which would restrict the soil settlement above the pipeline. The adjusted settlement formula shows good agreement with the measured data, facilitating approximate calculations for both surface and pipe settlements. The correction factor a ranges from 0.50 to 0.90, while b ranges from 0.95 to 1.20.The elastic modulus and the burial depth of the pipeline had a great effect on the stress of the pipeline, but a smaller effect on its settlement. However, the soil loss rate greatly affected both the settlement and stress of the pipeline. Moreover, the pipeline risk level distribution map can quickly identify the risk status of the pipeline.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1219-1226
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• 2005

In this study, crest settlement characteristics of CFRD (Concrete Faced Rockfill Dam) and ECRD (Earth Cored Rockfill Dam) were analysed through the instrumentation data from representative 7 large dams in Korea. Also, We have studied the effect of valley shape and uniaxial compressive strength of intact rock to better understand the impact of the parent rock strength and the valley shape on the long term crest settlement of CFRDs. From the results, we found that the valley shape and strength of intact rock on crest settlement of dams are an important parameters. As a result, we obtained that the maximum crest settlement of CFRD is larger than that of ECRD and long term crest settlement rate per dam height of rockfill dams is less than 0.60% during service period.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.147-158
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• 2001

In general, two methods have been used to predict settlement of soft ground. One method is Terzaghi's one dimensional consolidation theory which gives time-settlement relationship using the standard consolidation test results. The other is forecasting method of ground settlement to be occured in the future using in-situ monitoring data. The above both methods have some defects in application manner or in itself especially in very deep and soft clayey ground. In view of the lessons and experiences of soft ground improvement projects, several techniques were proposed for more accurate theorectical calculation of consolidation settlement as follows ; ① Subdivision of soft ground, ② Consideration of secondary compression, ③ Using the modified compression index, etc. And also, revised hyperbolic fitting method was suggested to minimize the error of predicted future settlement. In addition, revised De-Beer equation of immediate settlement of loose sandy soil was proposed to overcome the tendency to show too small settlement calculation results by original De-Deer equation. And also, considering the various effects of settlement delay in the improved ground by vertical drains, time-settlement caculation equation(Onoue method) was revised to match the tendency of settlement delay by using the characteristics of discharge capacity decreases of vertical drain with time elapse by the pattern of hyperbolic equation.

• Structural Engineering and Mechanics
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• v.84 no.5
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• pp.699-706
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• 2022

Settlement control techniques are critical for the safety of shield tunnel constructions, especially for facing complex situations. In this study, the shield tunnel structure from Huaita east road station to Heping Road station in Xuzhou metro No.3 line (China) is taken as engineering background, which has various complex problems of the upper-soft and lower-hard composite stratum conditions, twin curve shield tunnels, and underpass the foundation of the piled raft. The deformation characteristics of shield tunnelling passing through buildings are explored. Subsequently, comprehensive research methods of numerical simulation and field measurement are adopted to analyzing the effectiveness of settlement control by using the top grouting technique. The results show that the settlement of the buildings has obvious spatial characteristics, and the hysteresis effect can be obviously observed in soil deformation caused by shield construction. Meanwhile, the two shield constructions can cause repeated disturbances, reducing the soil deformation's hysteresis effect. Moreover, the shield tunnel's differential settlement is too large when a single line passes through, and the shield construction of the outer curve can cause more significant disturbance in the tunnel than the inside curve. Notably, the proposed process control parameters and secondary topgrouting method can effectively control the deformation of the shield tunnel, especially for the long-term deformation.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.702-706
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• 2009

From the result of analysis the necessity of root fixing stone construction through the result of finite element method, following results were acquired. 1. The consolidation settlement by stone weight is small amount so that it is interpreted there is no stone settlement reducing effect by root fixing stone. 2. It is interpreted that there is no effect existence and nonexistence of the heaving soil to the settlement. 3. There is little settlement reducing effect by root fixing stone but there may be protection of excavation effect. Therefore, for long-term stability, installing the root fixing stone to the section where the typhoon effect directly would be proper.

• Journal of the Korean Geotechnical Society
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• v.26 no.10
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• pp.39-47
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• 2010

In order to investigate the effect of variation characteristics of compression index on the spatial distribution of consolidation settlement, this study presents the estimation methods of the distribution of consolidation settlement and compares the estimated settlements. When the variation of compression index is considerable, the ordinary cokriging is more reliable in estimating the compression index than ordinary kriging because smoothing effect of ordinary cokriging is smaller than that of ordinary kriging. The spatial distribution of consolidation settlement estimated by considering both the variation of compression index and void ratio (CASE-1) is different from that estimated by using the mean value of all soil properties (CASE-2). The settlement of CASE-1 shows the larger variation at short distances rather than that of CASE-2. Whereas the spatial settlement distribution of CASE-1 is affected by the spatial distributions of compression index as well as the thickness of consolidation layer, that of CASE-2 is significantly influenced by the distribution of consolidation layer thickness.

• Journal of Agricultural Extension & Community Development
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• v.29 no.2
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• pp.99-110
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• 2022

This study aims to examine the characteristics of farming settlement in young farmers. In order to analyze the effect of each characteristic on young farmers' intention for settling into farming, an ordered logit model was employed. As for the individual characteristics affecting their intention for settling into farming, age and the highest education level showed a positive effect, while family-run farming had a negative effect, which was found statistically significant. For the financial characteristics, farm income had a statistically significant positive effect. On the other hand, the social and policy characteristics did not show any statistically significant effect.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.03a
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• pp.365-372
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• 1998