• Journal of the Korean GEO-environmental Society
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• v.12 no.4
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• pp.43-51
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• 2011

Many electric poles in the softground have been collapsed due to external load. In this study, 10 types of tests were performed with variation of location, numbers and depths of anchor blocks as well as depth of poles to find horizontal earth pressure through full scale pull-out tests. The horizontal earth pressure increased with embedded depth of electric pole, and earth pressure of lower passive zone decreased. The deeper of anchor block, earth pressure of passive zone becomes less. lateral displacements showed differences depending on location, numbers and depth of poles. The bending is generated in the upper part at the initial load, but it moved to central part as load increased. The maximum horizontal displacement decreased to 1/1.6 at -0.5m depth of anchor block and 1.3m additional laying depth of poles into ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.779-786
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• 2002

To find a long term horizontal movement of superstructure caused by seasonal thermal change, several types of gages are installed such as soil earth pressuremeter behind stub abutment and jointmeter between approach slab and relief slab. As results, maximum passive earth pressure behind integral bridge abutments centerline with lateral movement of superstructure is about 1/6 of classic Rankine's earth pressure. And its distribution is not triangular but rectangular shape due to shape behind integral bridge abutments.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.23-35
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• 2009

This study was performed to investigate the bending stresses of tunnel shotcrete as a function of the coefficient of lateral earth pressure. To perform this study, a large scale model tunnel with an one-lane horseshoe shaped road tunnel was prepared. The 3 dimensional numerical analyses were carried out to verify the results obtained from the model tests. For the loading system during the tests, 11 cylinder pressure jacks which can be controlled individually were used to simulate various loading conditions. The tests were preformed three times with three different lateral earth pressure coefficients of 0.5, 1.0 and 2.0. The bending stresses of shotcrete measured in tests were compared and analyzed with those calculated from numerical analyses. As a result, it was found that the bending compressive stresses obtained from numerical analyses were similar to those of tunnel model tests and bending tensile stresses were slightly overestimated during numerical analyses.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.419-426
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• 2000

The purpose of this study is to present the application of WFS co-mixtures for retaining wall as flowable backfill. The fly ash, generated at the Tae-An thermoelectric power plant, was used in this research and was classified as Class F. Green Sand, Furane Sand, and Coated Sand, which had been used at a foundry located in Pusan, were used. Couple of laboratory tests and small scale retaining wall tests were performed to obtain the physical properties of the WFS co-mixtures and the possibility of backfill materials of retaining wall. The range of permeability for all the co-mixtures was from 3.0${\times}$10$\^$-3/ cm/s to 6.0${\times}$10$\^$-5/ cm/s. The unconfined strength of the 28-day cured specimens reached around 550kPa. Results of the consolidated-undrained triaxial test showed that the internal friction angle is between 33.5$^{\circ}$ and 41.8$^{\circ}$. The lateral earth pressure against wall decreased up to 80% of initial pressure within a 12 hours and the total lateral earth pressure is less than that of typical granular soil. It was enough to construct the backfill for the standard retaining of 6m with just two steps, like fill the co-mixtures for half of retaining wall, and then fill the others after 1 day. The stability of retaining wall for overturning and sliding increased as the curing time elapsed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.708-712
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• 2008

Piles and pile foundations have been in common use since very early times. Usually function of piles is to carry load to a depth at which adequate support is available. Another important use of piles is to furnish lateral support and nowadays it is getting highlighted due to the wind load, lateral action of earthquake, and so on. After Broms (1964), many researchers have been suggested methods for estimating lateral capacity of pile. But each method assumes different earth pressure distribution and lateral earth pressure coefficient and it gives confusion to pile designers. Lateral earth pressure, essential in lateral capacity estimation, influenced by pile's behavior under lateral load. Prasad and Chari (1999) assumed the rotation point of pile and suggested an equation of ultimate lateral load capacity. In this study, we investigate the depth of rotation point in both homogeneous soil and multi layered soil, and compare to the estimation value by previous research. To model the pile set up in the sand, we use the chamber and small scale steel pile, and rain drop method. Test results show the rotation point is formed where the Prasad and Chari's estimation value, and they also show multi layered condition affects to location of rotation point to be scattered.

• Geotechnical Engineering
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• v.8 no.4
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• pp.81-98
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• 1992

Deep excavation increases utility of underground spaces for high buildings. subways etc. To excavate vertically the underground, safe earth retaining walls and supporting systems should be prepared. Recently anchors have been used to support the excavation wall. The anchored excavation has some advantages toprovide working space for underground construction. In this paper the prestressed anchor loads were measured by load cells which attacted to the anchors to support the excavation walls at eight construction fields. where under-ground deep excavation was performed on cohesionless soils. The lateral pressures on the retaining walls, which are estimated from the measured anchor forces, shows a trapezoidal distribution that the pressure increases linearly with depth from the ground surface to 30% of the excavation depth and then keeps constant value regardless of the stiffness of the walls. The maximum lateral pressure was same to 63% of the Ranking active earth pressure or 17% of the vertical overburden pressure at the final depth The investigation of the measured lateral pressure on the anchored excavation walls shows that empirical earth pressure diagram presented by Terzaghi-Peck and Tschebotarioff could be applied with some modifications to determine anchor loads for the anchored excavation in cohesionless soils.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.1
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• pp.65-74
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• 2002

This paper intends to investigate such effects through experiments. The contents of the investigation are effects of position of repeated loading and unloading, passing frequency. For the purpose of the investigation an experimental load-deflection system is developed and the system is possible to measure deflection of the wall and earth pressure due to different size of strip loading and cyclic loading. The findings from the experiments are as follows: 1. As repeated loading approaches to the wall, the measured horizontal residual earth pressure agrees well with Rowe's empirical formula, while as the loading is far from the wall the earth pressure consists with Boussinesq's and Spangler's formulas. Also it is found that below 0.6m depth from ground surface the effects of repeated loading can be nearly neglected. 2. From comparison analyses of earth pressure theories and experimental results, a reagression equation is suggested herein, and earth pressure at any depth and maximum earth pressure due to cyclic loading can be estimated from the equation.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.606-611
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• 2009

MiStrut is a new method to establish structural stability in designing braced excavations by making a rigid connection between top-level steel beams and soldier beams. MiStrut has a function of working as a strut as well as supporting cover plates of top-level steel beams. The structural mechanism of MiStrut is supposed to reduce flexural deformation of soldier beams, which may lead to reduced lateral earth pressures behind excavation. In this research, for verification of the performance of MiStrut, shear-wave velocities of subsurface soil before and after excavation was compared. The rigid connection of main girder beams with soldir beams reduced shear-wave velocity by 67% and lateral earth pressures by 90%, which indicates that MiStrut is effective development in reducing lateral earth pressures on braced excavation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.4
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• pp.315-326
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• 2004

This study performed model tunnel tests in order to investigate the influence of discontinuity condition of rock mass to the stress and deformation of tunnel lining. Tests were carried out changing the direction of main joint and lateral earth pressure condition of rock mass. Test results revealed that the axial force in tunnel lining showed a tendency of decrease with the presence of joints. It decreased much with the increase of lateral earth pressure coefficient. And, it also showed that the location or maximum displacement and maximum stress in lining were changed by the direction of main joint of rock mass. The tangential stress and normal stress showed the difference above the maximum twenty times as lateral earth pressure coefficient due to effect of joints increased. Also, these tendencies of concentration of tensile stress in tunnel lining were confirmed by elastic theory.

• Geomechanics and Engineering
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• v.16 no.6
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• pp.643-654
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• 2018

Tunnel excavation leads to a disturbance on the initial stress balance of surrounding soils, which causes convergences around the tunnel and settlements at the ground surface. Considering the effective impact of settlements on the structures at the surface, it is necessary to estimate them, especially in urban areas. In the present study, ground settlements due to the excavation of East-West Line 7 of the Tehran Metro (EWL7) and the Abuzar tunnels are evaluated and the effect of the lateral earth pressure coefficient ($K_0$) on their extension is investigated. The excavation of the tunnels was performed by TBMs (Tunnel Boring Machines). The coefficient of lateral earth pressure ($K_0$) is one of the most important geotechnical parameters for tunnel design and is greatly influenced by the geological characteristics of the surrounding soil mass along the tunnel route. The real (in-situ) settlements of the ground surface were measured experimentally using leveling methods along the studied tunnels and the results were compared with evaluated settlements obtained from both semi-empirical and numerical methods (using the finite difference software FLAC3D). The comparisons permitted to show that the adopted numerical models can effectively be used to predict settlements induced by a tunnel excavation. Then a numerical parametric study was conducted to show the influence of the $K_0$ values on the ground settlements. Numerical investigations also showed that the shapes of settlement trough of the studied tunnels, in a transverse section, are not similar because of their different diameters and depths of the tunnels.