• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.435-440
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• 2000

It is important to pay careful attention to construction backfill for the structural integrity of concrete box culvert. The stability of the surrounding soil is important to the structural performance of most culverts. Good compaction by the dynamic compaction roller with big capacity is as effective as good backfill materials to increase the structural integrity of culvert. However structural distress of the culvert could be occur due to the excessive earth pressure by dynamic compaction load. In this study, 16 box culverts were constructed with various compaction materials and construction methods. Three types of on-site soils such as subbase, subgrade and roadbed materials were used as backfill materials in the test program. Compaction methods were adapted based on the site conditions. In most cases, dynamic compaction rollers with 10 to 16 ton weights were used and vibration speed were applied from 2400 to 2500 rpm for the great compaction energy. Some backfill compactions with good quality soils were carried out to examine the effect of EPS(Expanded Polystyrene) panels with changes of compaction thickness. This paper presents the main results of the research conducted to access the engineering performance of the backfill materials. The characteristics of earth pressures are discussed. It is observed that subgrade and roadbed materials are needed more careful compaction than subbase materials. It is shown that EPS panels are effective to mitigate dynamic lateral earth pressure on the culverts. It is also obtained that the dynamic pressure depends on the soil properties. In addition, the coefficient of dynamic earth pressure (K$\sub$dyn/=ΔP$\sub$H/ ΔP$\sub$V/) during compaction is discussed.

• Geotechnical Engineering
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• v.4 no.1
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• pp.7-16
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• 1988

The safety factor has been used widely and uniquely at present to check the safety of the structure . However, probability of failure would be logically attempted to check the reliability of the structure in future Coulomb's theory or Rankine's theory has been applied in practice to retaining earth structure in spite of the fact that the lateral earth pressure, which is the primary factor in the determination of wall structure, depends on the modes of wall movement . This study is concentrated on the two modes of , wall movement (active case rotation about bottom(AB) , active case rotation about top(AT)) of the overturning'failure of vertical wall with horizontal sand backfill . The static active earth pressure is determined by applying each of Coulomb's theory, Dubrova's redistribution theory and Chang's method The earthquake active earth pressure is determined by adding Seed and Whitman's earthquake pressure to the static earth pressure , On the condition that design variables are fixed with each of the above earth pressure, reliability is analyzed using the recently developed method of AFOSM (Advanced First Order Second Moment)

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.163-171
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• 2001

It is important to pay careful attention to the backfill construction for the structural integrity of concrete box culvert. To increase the structural integrity of culvert good compaction by the dynamic compaction roller with big capacity is as effective as good backfill materials. However structural distress of the culvert could be occurred due to the excessive earth pressure by great dynamic compaction load. In this study, two box culverts were constructed with change compaction materials and construction methods. Two type of on-site soils such as subbase and subgrade materials were used as backfill materials. In most case, dynamic compaction rollers with 11 to 12 ton weights were used and vibration frequency were applied from 2000 to 2500 rpm for the great compaction energy. Backfill compactions with good quality soils were carried out to examine the effect of cushions on dynamic lateral soil pressure. Expanded polystyrene (EPS) and rubber of tire were adapted as cushion materials and they are set on the culverts before backfill construction. This paper presents the main results on the characteristics of dynamic earth pressures. Test result indicates that the amounts of increased dynamic pressures are affected with backfill materials, depth of pressure cell, and compaction condition. The earth pressure during compaction can give harmful effect to box culvert because the value of dynamic earth pressure coefficient $(\DeltaK_{dyn}=\DeltaK\sigma_h\DeltaK\sigma_v)$ during compaction is greater than that of static condition. It was observed that cushion panels of EPS(t=10cm) and rubber(t=5cm) are effective to mitigate dynamic lateral pressure on the culverts.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.27-36
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• 2005

The performance of innovative prestressed support (IPS) earth retention system applied in urban excavation was presented and investigated. The IPS wales provide a high flexural stiffness to resist the bending by lateral earth pressure, and the IPS wales transfer lateral earth pressure to Corner struts. The IPS wale provides a larger spacing of support, economical benefit, construction easiness, good performance, and safety control. In order to investigate applicability and stability of the IPS earth retention system, the IPS system was instrumented and was monitored during construction. The IPS system applied in urban excavation functioned successfully. The results of the field instrumentation were presented. The measured performances of the IPS earth retention system were investigated and discussed.

• Journal of the Korean Geotechnical Society
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• v.24 no.3
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• pp.25-34
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• 2008

A finite element analysis was performed for new earth retention system with prestressed wales. A 3D finite element model was adopted in this study to investigate the behavior of the earth retention system with prestressed wales. A procedure of the 3D finite element modeling of this earth retention system was presented. The procedure included the modeling of soil, wall, strut, and members of prestressed wale system which consists of wale, support leg, and steel wires, and the interface modeling of soil-wall and wall-wale. The numerical predictions of lateral wall deflection, and axial load on the members of prestressed wale systems and struts were evaluated in comparison with the measurements obtained from field instruments. A sensitivity analysis was performed using the proposed 3D finite element model to investigate the behavior of new earth retention system on a wide range of prestress load conditions of steel wires. The lateral deflection of the wall and wale, the bending moment of the wale, and the lateral earth pressure distribution on the wall were computed. Implications of the results from this study were discussed.

• Geotechnical Engineering
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• v.4 no.2
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• pp.25-32
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• 1988

This paper first presents the distributions of static lateral earth pressure in case of translational o.all movement (ATRA) , obtained respectively by the Dubrova method and by the method where Chang's idea is applied to the former, acting on the rigid retaining vertical wall with horizontal sand backfill. Total active resultant forces and the points of application of those forces, calculated results by the two methods, are compared with the experimental results recently published by Fang Y.S. and Ishibashi I. A comparative study about the distribution of static lateral earth pressurein each case of rotation about top(AT) and base (AB), on which the writer studied previously, is also conducted along with the above experimental results. The following results are obtained 1) In case of AT and ATRA, the experimental results are in good agreement with the calculated results by the Dubrova's method. 2) In case of AB, the results of the Dubrova's method are very inconsistent with those of model test, where as th method 9.here Chang's idea is applied, corresponds well, even though there is a small deviation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.343-355
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• 2017

In this study, an Assembled Earth Retaining Wall (AER wall) is newly proposed. The AER wall combined stabilizing piles names as Back Supporting Beam is developed to improve stability and economics of existing retaining walls. For the verification of the AER wall, the field model tests and 3D numerical analyses were performed. As a result of the field tests, it can be confirmed that the earth pressure is considerably reduced compared with the L-shaped retaining wall. Also, the 3D numerical analyses show that AER wall is at least 29.85% more effective at lateral displacement than general L-shaped retaining wall. In other words, AER wall is expected to raise economical efficiency because of excellent mechanical stability of Back Supporting Beam.

• Tunnel and Underground Space
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• v.26 no.3
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• pp.192-200
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• 2016

We analyzed the behavior of the lining segments considering the middle slab and lateral pressure coefficients when planning the construction of a duplex tunnel for the underground network. Reviewed segment lining analysis for research, the analytical model was determined for duplex tunnel. Also reviewed the vertical load, and a load of middle slab is considered the static load and the live load by vehicles. Section force by middle slabs a load applied was mainly generated in the lower tunnel had the greatest effect on the bending moment. In addition, the bending moment acting direction changes appeared with a large variable, and the section force according to the load applied to the middle slab is relatively constant and the effect on the segment lining from the smallest section force of the lateral pressure coefficient of 1.00 was found to occur appears most significantly. As a result of this research to identify the behavior of the slab and the segment lining by the effect of the lateral pressure coefficient (K) of the duplex tunnel will be able to present a method of the duplex tunnel structure is reasonable and economical design.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.217-229
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• 2024

Determining lateral earth pressure coefficient (EPC) K is a classic problem in geotechnical engineering. It is a key parameter for estimating the stresses in backfilled openings. For backfilled openings with rigid and immobile walls, some suggested using the Jaky's at-rest earth pressure coefficient K₀ while other suggested taking the Rankine's active earth pressure coefficient K_a. A single value was proposed for the entire backfilled opening. To better understand the distributions of stresses and K in a backfilled opening, a series of laboratory tests have been conducted. The horizontal and vertical normal stresses at the center and near the wall of the opening were measured. The values of K at the center and near the wall were then calculated with the measured horizontal and vertical normal stresses. The results show that the values of K are close to K_a at the center and close to K₀ near the wall. Furthermore, the experimental results show that the horizontal stress is almost the same at the center and near the wall, indicating a uniform distribution from the center to the wall. It can be estimated by analytical solutions using either K_a or K₀. The vertical stress is higher near the center than near the wall. Its analytical estimation can only be done by using K_a at the center and K₀ near the wall. Finally, the test results were used to calibrate a numerical model of FLAC2D, which was then used to analyze the influence of column size on the stresses and K in the backfilled opening.

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.147-155
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• 2001

좁은 되메움 공간의 벽체가 연직 또는 한쪽 벽체만이 경사진 경우 수평토압에 관한 연구는 국내외에서 상당히 진전되어 왔으나, 대칭으로 경사진 경우의 연구는 미흡한 실정이다. 본 연구는 되메움 공간의 벽체가 대칭으로 경사지고 벽체간 하부폭이 다를 때 발생되는 수평토압에 관한 거동을 구명하기 위하여 시도되었다. 이를 위하여 모형토조를 사용하여 되메움 공간의 벽체가 대칭으로 경사진 경우 벽체의 경사각, 하부폭, 벽마찰각, 상대밀도를 변화시켜 총 24종류의 모형실험을 수행하였고, 이 결과를 Kellogg(1993)제안식, 벽면경사를 고려한 수정 제안식 및 벽면마찰반력으로부터 구한 수평토압과 비교, 분석하였다. 연구 결과 벽면마찰반력을 고려한 경우 평균연직토압을 적용하였음에도 Arching 효과가 발휘된 실험결과와 가장 근소한 차이를 나타내었다.