• 한국지반공학회지:지반
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• 제8권4호
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• pp.51-66
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• 1992

최근과 같이 토목공사가 대형화되고 다양화됨에 따라 용지의 효율적 이용을 위해 옹벽 구조물의 축조는 필수적이다. 옹벽 설계시 옹벽자체에 대해서는 신뢰성과 적합성에 대해 신중을 기하면서 현실적으로 볼때 뒤채움에 대한 중요성을 가볍게 생각하는 경우가 많다. 본 논문에서는 옹벽체계를 원형에 가깝게 설계제작하여 고정 벽에서 여러 형태의 반복 연속 하중, 롤러 다짐하중, 뒤채움 작업공간, 기타 여러상태에서 실험을 하여 그 결과를 이론적으로 해석하고 Computer Program을 만들어 실험식을 만들고 타이론식과 결과를 비교분석하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.660-670
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• 2009

Neighboring construction becomes mainstream of Ground excavation in downtown area. This causes the displacement, deformation, stress condition, etc of the ground surroundings. Therefore Neighboring construction have an effect on Neighboring structure. All these years a lot of Neighboring construction carried out, and the accumulation of technology also get accomplished. But earth retaining structure collapse happens yet. Types of earth retaining structure collapse are 12. 1. Failure of anchor or strut system, 2. Insufficiency of penetration, 3. H-pile Failure on excessive bending moment, 4. Slope sliding failure, 5. Excessive settlement of the back, 6. Deflection of H-pile, 7. Joint failure of coupled H-pile, 8. Rock failure when H-pile penetration is rock mass, 9. Plane arrangement of support systems are mechanically weak, 10. Boiling, 11. Heaving, 12. Over excavation. But field collapses are difficult for classification according to the type, because collapse process are complex with various types. When we consider the 12 collapse field, insufficient recognition of ground condition is 4 case. Thorough construction management prevents from fault construction. For limitations of soil survey, It is difficult to estimate ground condition exactly. Therefore, it should estimate the safety of earth retaining system, plan for necessary reinforcement, according to measurement and observation continuously.

• Geomechanics and Engineering
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• 제15권5호
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• pp.1061-1070
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• 2018

The main purpose of retaining wall methods for deep excavation is to keep the construction site safe from the earth pressure acting on the backfill during the construction period. Currently used retaining wall methods include the common strut method, anchor method, slurry wall method, and raker method. However, these methods have drawbacks such as reduced workspace and intrusion into private property, and thus, efforts are being made to improve them. The most advanced retaining wall method is the prestressed wale system, so far, in which a load corresponding to the earth pressure is applied to the wale by using the tension of a prestressed (PS) strand wire. This system affords advantages such as providing sufficient workspace by lengthening the strut interval and minimizing intrusion into private properties adjacent to the site. However, this system cannot control the tension of the PS strand wire, and thus, it cannot actively cope with changes in the earth pressure due to excavation. This study conducts a preliminary numerical analysis of the field applicability of the controllable prestressed wale system (CPWS) which can adjust the tension of the PS strand wire. For the analysis, back analysis was conducted through two-dimensional (2D) and three-dimensional (3D) numerical analyses based on the field measurement data of the typical strut method, and then, the field applicability of CPWS was examined by comparing the lateral deflection of the wall and adjacent ground surface settlements under the same conditions. In addition, the displacement and settlement of the wall were predicted through numerical analysis while the prestress force of CPWS was varied, and the structural stability was analysed through load tests on model specimens.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1038-1045
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• 2006

The Green Wall is highest eco-system among a segmental retaining wall systems. Recently, the demand of high segmental retaining wall (SRW) is increased in domestic. The soil nailing system is applied in order to maintain the high SRW stability for steeper slope. However, the proper design approach that can consider the earth pressure reduction effects in soil nailing system has not been proposed. This study was performed to introduce the design case by 'Two-Body Translation mechanism' to be able to consider distribution of earth pressure in the soil nailing when designing the green wall using soil nailing system. Also, this study attempts to evaluate the earth pressure change when advanced soil nailing system is constructed using $FLAC^{2D}$ ver. 3.30 program and 'Two-Body Translation mechanism'. Also in this study, various parametric studies using numerical methods as shear strength reduction (SSR) technique and limit equilibrium technique were carried out. In the parametric study, the length ratio and the bond ratio of the soil nailing were changed to identify the earth pressure reduction effect of the retaining wall reinforced by soil nailing.

• Geomechanics and Engineering
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• 제13권4호
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• pp.601-619
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• 2017

Cantilever retaining wall movements generally depend on the intensity and duration of ground motion, the response of the soil underlying the wall, the response of the backfill, the structural rigidity, and soil-structure interaction (SSI). This paper investigates the effect of material properties on seismic response of backfill-cantilever retaining wall-soil/foundation interaction system considering SSI. The material properties varied include the modulus of elasticity, Poisson's ratio, and mass density of the wall material. A series of nonlinear time history analyses with variation of material properties of the cantilever retaining wall are carried out by using the suggested finite element model (FEM). The backfill and foundation soil are modelled as an elastoplastic medium obeying the Drucker-Prager yield criterion, and the backfill-wall interface behavior is taken into consideration by using interface elements between the wall and soil to allow for de-bonding. The viscous boundary model is used in three dimensions to consider radiational effect of the seismic waves through the soil medium. In the seismic analyses, North-South component of the ground motion recorded during August 17, 1999 Kocaeli Earthquake in Yarimca station is used. Dynamic equations of motions are solved by using Newmark's direct step-by-step integration method. The response quantities incorporate the lateral displacements of the wall relative to the moving base and the stresses in the wall in all directions. The results show that while the modulus of elasticity has a considerable effect on seismic behavior of cantilever retaining wall, the Poisson's ratio and mass density of the wall material have negligible effects on seismic response.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.49-83
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• 2005

ESCP Project showed an urban excavation case and introduced design method for case of Soil-Structure behavior in urban excavation. In this case, a retaining structures design to analysis the behavior of retaining wall and adjacent structures in urban excavations was applied by using a Elasto-plastic beam and limit Equilibrium analysis and soil-structure interaction analysis. Reliable design of earth retaining structures and the ground adjacent to braced wall in urban excavation are often difficult due to many variable factors. The ground settlement and the damage of adjacent structures in urban excavation has been an imprtant issue. Therefore, the stability of the adjacent structures must be secured with the excavation support and research on the protection of adjacent structure is necessary.

• Geomechanics and Engineering
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• 제6권2호
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• pp.99-115
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• 2014

Uncertainties in design variables and design equations have a significant impact on the safety of geotechnical structures like retaining walls and slopes. This paper presents a possible framework for obtaining the partial safety factors based on reliability approach for different random variables affecting the stability of a reinforced concrete cantilever retaining wall and a slope under static loading conditions. Reliability analysis is carried out by Mean First Order Second Moment Method, Point Estimate Method, Monte Carlo Simulation and Response Surface Methodology. A target reliability index ${\beta}$ = 3 is set and partial safety factors for each random variable are calculated based on different coefficient of variations of the random variables. The study shows that although deterministic analysis reveals a safety factor greater than 1.5 which is considered to be safe in conventional approach, reliability analysis indicates quite high failure probability due to variation of soil properties. The results also reveal that a higher factor of safety is required for internal friction angle ${\varphi}$, while almost negligible values of safety factors are required for soil unit weight ${\gamma}$ in case of cantilever retaining wall and soil unit weight ${\gamma}$ and cohesion c in case of slope. Importance of partial safety factors is shown by analyzing two simple geotechnical structures. However, it can be applied for any complex system to achieve economization.

• Steel and Composite Structures
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• 제31권6호
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• pp.629-640
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• 2019

The investigation of retaining wall structures behavior under dynamic loads is considered as one of important parts for designing such structures. Generally, the performance of these structures is under the influence of the environment conditions and their geometry. The aim of this research is to design retaining wall structures based on smart and optimal systems. The use of accuracy and speed to assess the structures under different conditions is one of the important parts sought by designers. Therefore, optimal and smart systems are able to have better addressing these problems. Using numerical and coding methods, this research investigates the retaining wall structure design under different dynamic conditions. More than 9500 models were constructed and considered for modelling design. These designs include height and thickness of the wall, soil density, rock density, soil friction angle, and peak ground acceleration (PGA) variables. Accordingly, a neural network system was developed to establish an appropriate relationship between data to obtain safety factor (SF) of retaining walls under different seismic conditions. Different parameters were analyzed and the effect of each parameter was assessed separately. According to these analyses, the structure optimization was performed to increase the SF values. The optimal and smart design showed that under different PGA conditions, the structure performance can be appropriately improved while utilization of the initial (or basic) parameters leads to the structure failure. Therefore, by increasing accuracy and speed, smart methods could improve the retaining structure performance in controlling the wall failure. The intelligent design process of this study can be applied to some other civil engineering applications such as slope stability.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.223-228
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• 2000

The principle objective of this study is to make an integrated development environment with an expert system for designing RC retaining walls. The program has several advantages over conventional design tools and characteristics of functions. It is easy to use and to obtain the technical reports with minor efforts. Various possible design alternatives can be compared, then the most optimal design can be selected in terms of construction cost and structural safety.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.248-259
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• 2010

In the case of relatively good ground and construction condition in the deep excavation for the construction of subway, railway, building etc., flexible earth retaining systems are often used in an economical point of view. It is generally known that the mechanism of behavior in the flexible earth retaining system is relatively more complicated than the rigid earth retaining system. Moreover in the case of long span strut supporting system the analysis of strut axial force change becomes more difficult when the differences of ground condition and excavation work progress on both sides of excavation section are added. When deeper excavation than the specification or installation delay of supporting system is done or change of ground condition is faced due to the construction conditions during construction process, lots of axial force can be induced in some struts and that can threaten the safety of construction. This paper introduces one example of long span deep excavation where struts and rock bolts were used as a supporting system with flexible wall structure. The characteristics of ground deformation and strut axial force change, the measured data obtained during construction process, were analysed, the effects of relatively deeper excavation than the specification on one excavation side and rapid drawdown of ground water level on the other excavation side were deeply investigated from the viewpoint of mutual influences between ground deformations of both excavation sides and strut axial force changes. The effort of this article aims to improve and develop the technique of design and construction in the coming projects having similar ground condition and supporting method.