• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.69-78
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• 2015

If an active displacement occurs on a wall with finite size, the ground behind the wall forms shapes of 3-dimensional wedges and 3-dimensional active earth pressure are applied on the wall. In the previous studies, shapes of 3-dimensional wedges were measured and the resultant of 3-dimensional active earth pressure has been calculated. In this study, the magnitude and the distribution of 3-dimensional active earth pressure depending on the size of a rectangular wall, which was defined by the aspect ratio (h/w), that is, the ratio between the height and the width of wall, were measured and compared with previous 3-dimensional models. The result shows that, the horizontal displacement (S) of the wall is approx 0.12% of the height of wall (h). The resultant 3-dimensional active earth pressure is similar to that of Karstedt (1982). The distributions of earth pressures on the wall are parabolic shape. The peak earth pressure was measured at the 0.5~0.55 depth from the ground surface. The reduction factor of 3-dimensional active earth pressure against the 2-dimensional earth pressure (${\alpha}$) depending the aspect ratio (h/w) is presented by the diagram.

• Journal of the Korean Geosynthetics Society
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• v.12 no.2
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• pp.55-66
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• 2013

The experiment of model soil structures has been executed for the soil retaining wall in various conditions of excavation, in this study, to analyze the behavior of the corner of opening. The ground for experiment has been constituted with the sandy soil of relatively loose density, the construction condition has been divided into the opening length of corner, embedded depth, existence of strut, etc., and the excavation has been carried out for 4 stages in total. The behavior characteristics at the corner of opening area has been verified by concentrate analysis of the displacement of wall and the subsidence of ground surface, for each construction and excavation condition, using the measuring instrument mounted inside the model soil structure. In the result of experiment, it has been analyzed that the opening area of corner is unstable structurally compared to the linear area, as it shows that the wall displacement and subsidence of ground surface have been increased when the opening length of corner gets longer. The longer the embedded depth, ground surface settlement of coner was decreased 40%. To apply deeper embedded depth than designed estimate was an advantage in the safety. As a result of the analysis of coner behavior with added struts, maximum surface settlement and maximum horizontal displacement was evaluated 40% and 30%, respectively. Hence increased embedded depth with the added struts in coner edge was effective in the safety.

• 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.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.5
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• pp.193-202
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• 2023

In this paper, a dynamic centrifuge model test was conducted on a 24.8-meter-deep excavation consisting of a 20 m sand layer and 4.8 m bedrock, classified as S3 by Korean seismic design code KDS 17 10 00. A braced excavation wall supports the hole. From the results, the mechanism of seismically induced earth pressure was investigated, and their distribution and loading points were analyzed. During earthquake loadings, active seismic earth pressure decreases from the at-rest earth pressure since the backfill laterally expands at the movement of the wall toward the active direction. Yet, the passive seismic earth pressure increases from the at-rest earth pressure since the backfill pushes to the wall and laterally compresses at it, moving toward a passive direction and returning to the initial position. The seismic earth pressure distribution shows a half-diamond distribution in the dense sand and a uniform distribution in loose sand. The loading point of dynamic thrust corresponding with seismic earth pressure is at the center of the soil backfill. The dynamic thrust increased differently depending on the backfill's relative density and input motion type. Still, in general, the dynamic thrust increased rapidly when the maximum horizontal displacement of the wall exceeded 0.05 H%.

• Journal of the Korean GEO-environmental Society
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• v.18 no.2
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• pp.47-51
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• 2017

In this study, the optimization algorithm by inverse analysis that is the core of the adaptive management technique was adopted to update the soil engineering properties based on the ground response during the construction. Adaptive management technique is the framework wherein construction and design procedures are adjusted based on observations and measurements made as construction proceeds. To evaluate the performance of the adaptive management technique, the numerical simulation for the triaxial tests and the synthetic deep excavation were conducted with the Hardening Soil model. To effectively conduct the analysis, the effective parameters among the parameters employed in the model were selected based on the composite scaled sensitivity analysis. The results from the undrained triaxial tests performed with soft Chicago clays were used for the parameter calibration. The simulation for the synthetic deep excavation were conducted assuming that the soil engineering parameters obtained from the triaxial simulation represent the actual field condition. These values were used as the reference values. The observation for the synthetic deep excavation simulations was the horizontal displacement of the support wall that has the highest composite scaled sensitivity among the other possible observations. It was found that the horizontal displacement of the support wall with the various initial soil properties were converged to the reference displacement by using the adaptive management technique.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.87-99
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• 2023

Ground excavation inevitably causes ground displacement of adjacent ground, and structures and facilities exposed to ground displacement may suffer various damages. Therefore, in order to minimize the damage and damage to adjacent structures and facilities caused by excavation, ground displacement (settlement and horizontal displacement) in the adjacent ground caused by excavation must first be predicted. There is many ground displacement information induced by general braced cut excavation, but the information is not enough for circular shaft excavation. This study aims to provide information on the estimation of ground settlement caused by circular shaft excavation through the case analysis of circular shafts and comparison with braced cut excavation. From this study, it was found that the use of the settlement criterion of braced cut excavation as the settlement management criterion for circular shaft excavation is a conservative approach in terms of safety. But when considering the economic aspect, it may result in overdesign of the wall and therefore, a more reasonable settlement criterion can be needed for circular shaft excavation.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.335-343
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• 1998

Recently, new experimental criteria for reinforced concrete frame structures in high seismic regions have been reported in United States. The objective of the criteria is to get more reliable test data which are valid to compare with other test data done by different researchers. The criteria precribe test method of specimens, analysis method of test data, and limiting values needed to specimens like drift angle, energey dissipation ratio, stiffness, and strength. These criteria might be usefel to get objective conclusion. Shear wall structures, which belong to one of earthquake resisting systems, also need this kind of criteria. But, the general response of shear wall structures is a little bit different from that of frame structures since shear wall restrains the horizontal displacement caused by horizontal force and increases the stiffness and strength. The objective of this paper is to propose a criterion for limiting drift and energy dissipation ratio of shear walls based on structural testing. These are the most important values for presenting the capacity of shear walls. Limiting drift and energy dissipation ratios were examined for tests on shear walls having ductile type failures. Test data were analyzed and compared to the results for a suggested acceptance criteria that involve a limiting drift that is a function of aspect ratio and a limiting energy dissipation ratio that is a function of displacement ductility and damping.

• Journal of the Korean Geosynthetics Society
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• v.11 no.2
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• pp.39-47
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• 2012

This paper describes large-scale pullout test results of geosynthetic strip, which can be applied in reinforced earth wall with block-type wall facing. The pullout tests are conducted to evaluate the strain distribution, the induced pullout force and the pullout strength. The maximum pullout force is appeared regardless of reinforcement width and normal stress when end displacement is less than 15 mm. The pullout behavior based on horizontal spacing of reinforcement was similar in relationship between pullout force and end displacement. The strain distribution and pullout force distribution of the geosynthetic strip are concentrated in the front part of reinforcement, and it appeared clearly in higher normal stress condition This means that the pullout behavior of geosynthetic strip is affected by the bond between soil and friction resistance reinforcement according normal stress. Therefore, the pullout resistance design is reasonable when pullout behavior of geosynthetic strip should be evaluated by effective length considering tensile characteristic.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1580-1587
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• 2005

To calculate the long-term allowable strength of geosynthetic reinforcement, replacement method was recommended. The isochronous creep curve by S. Turner was used to define the relation between creep strain and allowable strength. In isochronous curve at given time, one can read the allowable strength at allowable creep strain. The allowable strain gets from specification by directors or manufacturers according to the allowable displacement of reinforced structures. The allowable strength can be determined in relation to the allowable horizontal displacement each structures case by case. The effect of install damage on isochronous behaviors of geosynthetic reinforcement was little. In previous study, install damage increase the creep strain slightly. And the degradation was not identified. But it is supposed that degradation increase the creep strain. In conclusion, The recommended model to determine long-term allowable strength of geosynthetic reinforcements considering tensile deformation of reinforcement and soil is fit for proper, correct and economic design for reinforced earth walls.

• Ocean Systems Engineering
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• v.13 no.1
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• pp.57-77
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• 2023

In the present study, the total hydrodynamic pressure exerted by the fluid on walls of rectangular tanks due to horizontal excitations of different frequencies, is investigated by pressure based finite element method. Fluid within the tanks is invisid, compressible and its motion is considered to be irrotational and it is simulated by two dimensional eight-node isoparametric. The walls of the tanks are assumed to be rigid. The total hydrodynamic pressure increases with the increase of exciting frequency and has maximum value when the exciting frequency is equal to the fundamental frequency. However, the hydrodynamic pressure has decreasing trend for the frequency greater than the fundamental frequency. Hydrodynamic pressure at the free surface is independent to the height of fluid. However, the pressure at base and mid height of vertical wall depends on height of fluid. At these two locations, the hydrodynamic pressure decreases with the increase of fluid depth. The depth of undisturbed fluid near the base increases with the increase of depth of fluid when it is excited with fundamental frequency of fluid. The sloshing of fluid with in the tank increases with the increase of exciting frequency and has maximum value when the exciting frequency is equal to the fundamental frequency of liquid. However, this vertical displacement is quite less when the exciting frequency is greater than the fundamental frequency.