• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.66-75
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• 1993

Hydraulic experiments were performed in order to gain an insight into the quantitative differences between the perforated wall caisson and its solid wall counterpart in the local pressure distribution and caisson stability. The results showed that the wave forces acting on local walls were smaller in the perforated wall caisson than in the solid wall caisson. For the caisson stability, the critical weights of the perforated wall caisson also turned out to be smaller than those of the solid wall caisson. The Phenomenon was attributed to the dual effects inherent to the perforated wall caisson, which are the decrease of total horizontal force and the phase difference between the total horizontal and vertical forces.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.176-183
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• 1996

In order to reduce wave reflection from a breakwater, a perforated wall caisson is often used. A conventional perforated wall caisson breakwater for which the water depth inside the wave chamber is the same as that on the rubble mound berm has less weight than a vertical solid caisson with the same width and moreover the weight is concentrated on the rear side of the caisson. (omitted)

• Geomechanics and Engineering
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• v.27 no.5
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• pp.447-463
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• 2021

Caisson-type structures are widely used as quay walls in coastal areas. In Korea, for a long time, many caisson-type quay walls have been constructed with a low front water depth. These facilities can no longer meet the requirements of current development. This study developed a new technology for deepening existing caisson-type quay walls using grouting and rubble mound excavation to economically reuse them. With this technology, quay walls could be renovated by injecting grout into the rubble mound beneath the front toe of the caisson to secure its structure. Subsequently, a portion of the rubble mound was excavated to increase the front water depth. This paper reports the results of an investigation of the seismic behavior of a renovated quay wall in comparison to that of an existing quay wall using centrifuge tests and numerical simulations. Two centrifuge model tests at a scale of 1/120 were conducted on the quay walls before and after renovation. During the experiments, the displacements, accelerations, and earth pressures were measured under five consecutive earthquake input motions with increasing magnitudes. In addition, systematic numerical analyses of the centrifuge model tests were also conducted with the PLAXIS 2D finite element (FE) program using a nonlinear elastoplastic constitutive model. The displacements of the caisson, response accelerations, deformed shape of the quay wall, and earth pressures were investigated in detail based on a comparison of the numerical and experimental results. The results demonstrated that the motion of the caisson changed after renovation, and its displacement decreased significantly. The comparison between the FE models and centrifuge test results showed good agreement. This indicated that renovation was technically feasible, and it could be considered to study further by testbed before applying in practice.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.74-81
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• 2003

During the 1995 Hyogoken-Nambu earthquake, many caisson-type quay walls in Kobe Port moved several meters towards the seaside due to liquefaction and subsequent ground flow, To investigate the mechanism of quay wall damage, we carried out the numerical simulation using the 2-D effective stress analysis. Input earthquake motions used for the analyses are original Dip wave and the component wave in each compact support of wavelet transformation. The results suggested that the shear failure occurred in the foundation soil underneath the caisson type quay wall due to the deformation of the caisson type quay wall.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2317-2328
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• 2013

In this study, the effect of wave chamber slab on wave pressure along the first and second wall of the perforated caisson breakwater was investigated by performing physical experiment. The experiment was performed without and with the wave chamber slab of the perforated caisson by varying the front wall porosity. The discrepancy in magnitudes of the measured wave pressure along the both walls of the perforated caisson was apparent according to the existence of the wave chamber slab as significantly greater pressures were acquired for all the test cases when the wave chamber was closed upward by the slab. As a result, the magnitudes of the total wave force calculated by integration of the measured wave pressure also were much larger for the caisson breakwater having the wave chamber slab, exceeding the value based on the well known Takahashi's formula (Takahashi and Shimosako, 1994). With respect to the porosity of the front wall, meanwhile, higher pressures were obtained with a larger porosity, at both the first and second wall of the breakwater.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.461-464
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• 2006

The caisson of the inner wall type has a weak point that reflecting wave is big. Therefore it has been studied that the research of the decreasing reflecting wave using installation the perforated wall in front of caisson to decrease of that weak point. In this study, we analyzed the characteristic of reflection horizontal and diamond style vertical slit caisson using hydraulic model test. According to the results of experiments, we could confirm that diamond style vertical caisson has a reflection coefficient which has lower than horizontal caisson of the reflection coefficient of 5~10%.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.148-156
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• 2003

Shaking table tests and pseudo-static analysis were performed, in this study, on newly-designed aseismatic L-type caisson quay walls, which were constructed by extending the bottom plate of gravity quay walls into the backfill soil. The L-type quay walls are expected to give economical benefits by reducing the cross-sectional area of the wall while maintaining its aseismatic efficiency as much as the classical caisson gravity quay wall. To confirm the effectiveness of the L-type structure, the geometry of L-type quay walls were varied for shaking table tests. And, to verify the influence of backfill soils on the seismic behavior of quay walls, additional shaking table tests were performed on the L-type quay wall after the backfill soils were replaced by gravels and light materials. As a result, it was found that L-type caisson quay walls are good earthquake resistant structures but increasing the length of bottom plate did not proportionally increase the effectiveness of the structure in its aseismatic performance. Replacing the backfill soils by the gravels and light materials, contrary to our expectation, was not an effective measure in improving the seismic performance of L-type caisson quay wall.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.403-408
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• 2019

In general, the caisson having the perforated wall is used to for the purpose of reducing the wave reflection and wave overtopping. In this study, the hydraulic characteristics (reflection coefficient) of the perforated wall caisson chamber filled with aggregates (rocks) were investigated with hydraulic model tests. When the perforated wall chambers were filled with aggregates, the reflection coefficients would increase. However, it was confirmed that the rock filling method into the perforated wall chamber could secure the stability of the structures and satisfy the hydraulic characteristics at a certain level.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.67-76
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• 2017

In this study, the effect of caisson heel on the active earth pressure is investigated. Using limit analysis method, inclinations of slip surface developed above the heel with different lengths are analyzed. The shorter the heel length, the larger those of inside slip surface, however those of outside slip surface are not changed. According to the relative heel length, relationships of internal friction angle of backfill material - wall friction angle between caisson structure and backfill - friction angle acting on virtual section at the end of heel are presented. Earth pressures acting against caisson structure with relatively short heel are smaller than Rankine earth pressure but always greater than Coulomb earth pressure which does not consider the heel length.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.205-208
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• 2002

Numerous studies have been performed to develop an analytical model that can predict the reflection of regular or irregular waves from a perforated-wall caisson breakwater. Though such irregular wave models as Suh et at. (2001) become available, regular wave models are still in extensive use because of their simplicity. In the present study, using the regular wave model of Fuggazza and Natale(1992), the reflection of irregular waves from a perforated-wall caisson breakwater was calculated in several different methods. First, the regular wave model was re-validated by the hydraulic model tests. Though the model somewhat over-predicted the reflection coefficients at larger values and under-predicted them at smaller values, overall agreement was pretty good between calculation and measurement. Then, the regular wave model was applied to calculate the irregular wave reflection in the experiments of Suh et at.(2001) and Bennett et al. (1992). In applying the regular wave model to irregular wave reflection, several different methods were used. The results showed that it is the most reasonable to use the regular wave model repeatedly for each frequency component of the irregular wave specuum with the root-mean-squared wave height for all the frequencies .