• Geomechanics and Engineering
• /
• v.16 no.3
• /
• pp.321-329
• /
• 2018

Classic braced walls use struts and wales to minimize ground movements induced by deep excavation. However, the installation of struts and wales is a time-consuming process and confines the work space. To secure a work space around the retaining structure, an anchoring system works in conjunction with a braced wall. However, anchoring cannot perform well when the shear strength of soil is low. In such a case, innovative retaining systems are required in excavation. This study proposes an innovative earth-retaining wall that uses in situ soil confined in dual sheet piles as a structural component. A numerical study was conducted to evaluate the stability of the proposed structure in cohesionless dry soil and establish a design chart. The displacement and factor of safety of the structural member were monitored and evaluated. According to the results, an increase in the clearance distance increases the depth of safe excavation. For a conservative design to secure the stability of the earth-retaining structure in cohesionless dry soil, the clearance distance should exceed 2 m, and the embedded depth should exceed 40% of the wall height. The results suggest that the proposed method can be used for 14 m of excavation without any internal support structure. The design chart can be used for the preliminary design of an earth-retaining structure using in situ soil with dual steel sheet piles in cohesionless dry soil.

• Architectural research
• /
• v.4 no.1
• /
• pp.45-52
• /
• 2002

Selection procedures of earth retention systems are increasingly complex and directly related to the serviceability of the retaining structure selection systems since significant changes in earth retention technology motivates the review of design, and selection processes of earth retaining structures. Collection and classification of retaining structure selection knowledge are key issues because two expert groups, geotechnical and structural engineers, are mainly involved in the retaining structure selection. The course of natural tendency of expert knowledge are investigated considering the decision factors. The decision factors for selecting retaining structures are divided into four categories: application of the structure, and spatial, behavior, and economic constraints.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.46 no.2
• /
• pp.93-103
• /
• 2004

In trench excavation, essential factor of earth-retaining temporary work structure should be easy taking to pieces and movement, and dead weight must be less. This paper studies about the light weight material and application as earth-retaining structure to prevent the slope failure of sand soil ground caused by the variation of groundwater level in trench excavation. That is, light weight earth-retaining structural is proposed and a simulation with FEM on application of proposed structural in sandy soil is presented. The results are summarized as follows; (1) The study proposed FRP H-shaped pannel for the light weight member, and also presented estimation method about stability. (2) Mechanical property (bending moment, shear force, axial force, displacement) were changed according to groundwater level, but these values had been within enough safety rate and allowable stress. Therefore, proposed light weight pannel with FRP is available for bracing structure in trench excavation.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.9
• /
• pp.25-31
• /
• 2022

Attaching shelf to retaining structure leads to a decrease in the total lateral earth pressure. This decrease enables the retaining structures to become more stable, to have small displacement, and to exhibit lower bending moments, the relief shelves effects are analyzed using FEM in order to understand how they stabilize cantilever wall in this study. Several models are varied by changing location and width of shelves to realize earth pressure and displacements of retaining wall. The displacement is getting smaller because earth pressure acting on shelf increases as shelves locations are lower and width is longer. The ground settlement variation effects caused by relief shelves are studied also. The ground settlement increases abruptly where shelf location is between of 0.5H and 0.625H, and settlement decreases suddenly where shelf width is between b/h=0.375 and b/h=0.500. The shelf significantly reduces earth pressure and movement of the wall. This decrease in the lateral pressure increases the retaining structure stability.

• The Journal of Engineering Geology
• /
• v.18 no.4
• /
• pp.433-437
• /
• 2008

It's essential to build an earth retaining structure at the beginning and end point of a tunnel constructed in a colluvium area. A large scale of colluvial soil may cause a problem to the stability of the excavation ground. An excavation in colluvium has different behavior characteristics from those in a sandy soil due to unstable elements and needs counter measures for it. There are few systematic research efforts on the behavior characteristics of an earth retaining structure installed in colluvial soil. Thus this study set out to collect measuring data from an excavation site at the tunnel pit mouth in colluvium and set quantitative criteria for the safety of an earth retaining structure. After comparing and analyzing the theoretical and empirical earth pressure from the measuring data, the lateral earth pressure distribution acted on the earth retaining wall was suggested.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.1496-1503
• /
• 2005

The study on the lateral earth pressure is briskly preformed for various conditions such as type of retaining walls, ground condition, and type of supporting systems. It is not simple to determine the distribution of lateral earth pressure accurately, however, because the lateral earth pressure is affected by various factors. This study is performed to analyze the behavior of earth retaining walls for new excavation contacting with existing excavation by comparing with the site measuring values before and after new excavation. On the base of observation, the distribution of strut axial forces is similar to that of ganeral earth retaining walls, but strut axial forces is increased by removal of existing earth anchors. When new excavation is performed contacting with existing excavation, the axial force of strut is decreased because of soil exclusion in the behind walls, but that force is increased after new exeavation. The analysis result show that the installation of strut in middle part makes a effect to not only 1 adjacent strut, but 3-5 adjacent struts. Also during new excavation strut axial forces is decreased by relaxation of total earth retaining wall system.

• Geomechanics and Engineering
• /
• v.32 no.2
• /
• pp.179-191
• /
• 2023

To study the influences of tunneling on the earth pressure and ground settlement when the tunnel passes through the adjacent underground retaining structure, 30 two-dimensional model tests were carried out taking into account the ratios of tunnel excavation depth (H) to lateral width (w), excavation width (B), and excavation distance using a custom-made test device and an analogical soil. Tunnel crossing adjacent existing retaining structure (TCE) and tunnel crossing adjacent newly-built retaining structure (TCN) were simulated and the earth pressure variations and ground settlement distribution during excavation were analyzed. For TCE condition, the earth pressure increments, maximum ground settlement and the curvature of the ground settlement curve are negatively related to H/B, but positively related to H/s and H/w. For TCN condition, most trends are consistent with TCE except that the earth pressure increments and the curvature of ground settlement curve are negatively related to H/w. The maximum ground settlement is larger than that observed in tunnel crossing the existing underground structure. This study provides an assessment basis for the design and construction under confined space conditions.

• Geomechanics and Engineering
• /
• v.13 no.5
• /
• pp.715-742
• /
• 2017

Earth berms are often left in place to support retaining walls or piles in order to eliminate horizontal struts in excavations of soft soil areas. However, if the excavation depth is relatively large, an earth berm-supported retaining system may not be applicable and could be replaced by a multi-bench retaining system. However, studies on multi-bench retaining systems are limited. The goal of this investigation is to study the deformation characteristics, internal forces and interaction mechanisms of the retaining structures in a multi-bench retaining system and the failure modes of this retaining system. Therefore, a series of model tests of a two-bench retaining system was designed and conducted, and corresponding finite difference simulations were developed to back-analyze the model tests and for further analysis. The tests and numerical results show that the distance between the two rows of retaining piles (bench width) and their embedded lengths can significantly influence the relative movement between the piles; this relative movement determines the horizontal stress distribution in the soil between the two rows of piles (i.e., the bench zone) and thus determines the bending moments in the retaining piles. As the bench width increases, the deformations and bending moments in the retaining piles decrease, while the excavation stability increases. If the second retaining piles are longer than a certain length, they will experience a larger bending moment than the first retaining piles and become the primary retaining structure. In addition, for varying bench widths, the slip surface formation differs, and the failure modes of two-bench retained excavations can be divided into three types: integrated failure, interactive failure and disconnected failure.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2009.05b
• /
• pp.21-24
• /
• 2009

This study deals with the application of USN wireless inclinometer sensor for earth retaining structure safety measurement, The application of wireless inclinometer sensor has great advantage about real-time monitoring of earth retaining structure, It allows a construction manager to monitor movement data from anywhere connected through internet during the process of excavation for substructures of buildings, To validate the applicability of the wireless inclinometer sensor. laboratory and field tests have been performed, The results have shown that the measured values of wireless inclinometer sensor represent the behavior of H-pile well, Both convenience of sensor installation and real-time monitoring of earth retaining structure are confirmed, The proposed wireless measurement system provides a good basis for exact measurement of temporary substructures, More measurements and application are expected for the other excavation sites with various conditions.

• Journal of Digital Convergence
• /
• v.17 no.3
• /
• pp.205-213
• /
• 2019

In a construction site, excavation work has a close relation with temporary earth retaining structure. In order to build the underground structure most effectively in a narrow space, prevent soil relaxation of the external behind ground in excavation work, and maintain a ground water level, it is required to install a temporary earth retaining structure that secures safety. To prevent soil washoff in underground excavation work, the conventional method of temporary earth retaining structure is to make a temporary wall and build the internal support with the use of earth anchor, raker, and struct for excavation work. RSB method that improves the problem of the conventional method is to remove the internal support, make use of two-row soldier piles and bracing, and thereby to resist earth pressure independently for underground excavation. This study revealed that through the field application cases of RSB method and the measurement result, the applicability of the method for installing a temporary earth retaining structure, the assessment result, and displacement all met allowable values of measurement, and that the RSB method, compared to the conventional method, improved constructability and economy.