• Journal of the Society of Disaster Information
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• v.14 no.3
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• pp.367-378
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• 2018

Purpose: The objective of this study is to present a reasonable safety management of the anchored in-situ wall systems constructed in the ground conditions consisting of multi-layered soils underlain by bedrocks in the urban area of Korea. Method: Field measurements collected from collapse case histories with deep excavations were analyzed for the safety management of the wall systems supported by the earth anchors in terms of lateral displacement rates. Results: The average maximum lateral displacement rate in a collapsed zone of the in-situ wall significantly increased upon the completion of the excavation. Particularly, the collapse of the in-situ wall system due to the sliding occurring along the discontinuities of the rock produced a considerably large lateral displacement rate over a relatively short period. Conclusion: For predicting and preventing the collapse of the wall system during or after the excavation work, the utilization of the safety management criteria of the in-situ wall system by the lateral displacement rate was found to be much more reasonable in judging the safety of earthworks than the application of the quantitative management criteria which have been commonly used in the excavation sites.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.111-124
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• 1999

When deep excavation adjacent to an existing structure is performed, it is very important to minimize damage on the structure through the prediction of ground movement. In this paper, finite element analysis was performed to predict the ground movement, based on the data from site investigation and laboratory tests, when deep excavation close to a buried water tank was carried out in soft clay ground. The movement and stabilities of the soil-cement wall(SCW) and the adjacent structure were checked using the results of the analysis and the field measurement. The comparison between the measured and the predicted ground movements showed the significance of the excavation procedure and lowering of water level in the analytical model. In the future, it is needed to improve the prediction method for better estimation of the ground movement.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.71-76
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• 2015

Recently, people are increasingly interested in horizontal directional drilling (HDD) to construct oil and gas pipeline and utility pipeline in the urban area as one of trenchless methods. One of major issues during the HDD is the collapse of borehole, which may be the potential causes of ground collapse. This study investigated the effect of mud pressure on the borehole stability, using finite element analysis. Since the borehole is being drilled with a certain angle, three dimensional analysis should be performed. The borehole stability was examined by applying two different types of mud pressures, i.e., uniform and non-uniform, to the exterior surface of borehole. The results show that the high mud pressure at the beginning of drilling, i.e., at shallow depth, causes the borehole collapse, whereas the borehole was stable even at high mud pressure as the drilling depth increases. It can be said that the determination of maximum mud pressure is strongly related to the drilling depth.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.199-212
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• 2018

This research concerns the prediction method for ground movement and wall member force due to determination structural stability check and failure check during deep excavation construction. First, research related with excavation influence parameters is conducted. Then, numerical analysis for various excavation conditions were conducted using Finite Element Method and Beam-column elasto-plasticity method. Excavation analysis database was then constructed. Using this database, development of ANN (artificial neural network) was performed for each ground movements and using structural member forces. By comparing the numerical analysis results with ANN's prediction, it is validated that development of ANN can be used efficient for prediction of ground movement and structural member forces in deep excavation site.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.2
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• pp.153-167
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• 2024

Recently the ground settlement has been increasing in urban area according to development. And, this may attribute a groundwater level drawdown. This study presents an analysis of groundwater level drawdown for circular vertical shaft excavation of ｢◯◯◯◯ double track railway build transfer operate project｣. And, in-situ monitoring data and numerical analysis were compared. So, if we examine the groundwater level drawdown in design, ground conditions should be applied so that the site situation can be reflected. And, groundwater level should be considered a seasonal measurement in order to apply the appropriate groundwater level. It was confirmed a similar predicted value to groundwater level drawdown of in-situ monitoring data.

• Journal of the Korean GEO-environmental Society
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• v.18 no.2
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• pp.5-19
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• 2017

Underground excavation for building construction in Korea is changing from conventional support method (Strut, Ground anchor) to inside permanent support method by stability, economic, circumstances around excavation and etc. This study was selected the sites of Top-down, New Top-down, S.P.S, S.T.D and B.R.D in general use. This study was compared and analyzed a construction cost and period between aforementioned methods and conventional support method. Also, this study was confirmed the stability of temporary retaining wall by analysis for measurement data under construction. As a result, this study can grasp that most improved permanent support method is excellent in economic and constructability than conventional support method in case of deep excavation and rapid appearance of bedrock.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.609-623
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• 2018

If the ground is excavated in a depth which is deeper than the adjacent existing tunnel, the behavior of the braced wall is known to be greatly affected by the presence of the tunnel. By the way it is expected to be also affected by the structure on the ground surface, There are not many examples of studies which are conducted on this subject. As a result, largel scale model tests and analysis were conducted, to measure the behavior of the tunnel under the building whose location on the ground surface was varied during the adjacent ground excavation. For this purpose, the location of a building load was varied in 0 m, 1D, 2D on ground surface. In this paper, the behaviors of braced wall and adjacent tunnel was studied. Model tests in 1 : 10 scale were performed in real construction sequences. The size of test pit was $2.0m(width){\times}6.0m(height){\times}4.0m(length)$ in dimension. As a result, it was found that the stability of the existing tunnel under the influence of the building load on the ground surface adjacent to the braced wall.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.43-50
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• 2000

This paper presents the measured performance of in-situ walls using the measured data collected from various deep excavation sites in urban area. A variety of in-situ wall systems from 57 sites were considered, including H-pile walls, soil cement walls, cast-in-place pile walls, and diaphram walls. The examination included lateral wall movements as well as apparent earth pressure distributions. The measured data were thoroughly analyzed to investigate the effects of various components of in-situ wall system, such as types of wall and supporting system, on the lateral wall movement as well as on the apparent earth pressure distribution. The results wee then compared with the current design/analysis methods, and information is presented in chart formes to provide tools that can be used for design and analysis. Using the measured data, a semi-empirical equation for predicting deep excavation induced maximum lateral wall movement is suggested.

• Geotechnical Engineering
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• v.11 no.1
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• pp.63-78
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• 1995

Recently, in order to utilize more effectively underground space, deep excavations have been performed on building or subway construction in urban areas. In such excavations, anchors have been used to support the excavation retaining walls because the anchored excavation could provide wide working space for underground construction. The purpose of this paper is to establish empirical equations to be able to estimate the earth pressures acting on anchored excavation retention walls, based on the investigation of field measuring results, which were obtained from twenty seven building construction sites. The prestressed anchor force was measured by load cells which were attached to the anchor head, while the horizontal displacement of excavation walls were measured by inclinometers which were installed right'behind the retention walls. The lateral earth pressures acting on the anchored retention walls, which were estimated from both the measured anchor forces and the horizontal displacement of the walls, showed a trapezoidal distribution. There was some difference between the measured earth pressures acting on the anchored retention walls and the empirical earth pressures given by several empirical equations. Thus, the lateral earth pressures acting on anchored retention walls would be estimated by these empirical equations with some modifications.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.39-46
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• 2009

In this study, behavior of a rigid continuous wall, earth pressure distribution with construction stage, and axial force of earth anchors were evaluated based on field monitoring data and numerical analysis results. For this purpose, a construction site excavated using the diaphragm wall was selected and full instrumentation system was introduced. From monitoring results, it was found that the values of horizontal displacement of the wall measured from the inclinometers, which were installed within the diaphragm wall were similar to analytical value. The earth pressure increased with excavation progress due to jacking force of the ground anchors installed in previous excavation stages. When the excavation depth reached 60% of the final depth, observed earth pressure distribution was similar to that estimated from Peck's apparent earth pressure distribution. When the excavation depth was around 90% of the final depth, values of observed earth pressure showed middle values between those of Peck's and Tschebotarioffs apparent earth pressures. It was also observed that, when excavation depth is deep, values of the earth pressures from the rigid wall were similar to those estimated from conventional earth pressure distribution shape proposed for flexible walls.