• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.375-381
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• 2017

A full-scale field test was conducted to investigate the arching effect of an embankment pile. The arching effect calculated from the test results was compared with theoretical values. Measurements obtained from a load cell and an earth pressure cell during the field test reflected the arching effect of the embankment pile well. The arching effect measured by load cells for an embankment height of 3m or less was smaller than the theoretical value with the assumption of plain strain.The measured effect for a height of 4 m or more was larger than the theoretical value. In contrast to the consistent decrease of the theoretical arching effect, the arching effect obtained from the field test shows continually increasing trends. The arching effects calculated from the earth pressure cells were greater than those from the theory under the plain strain assumption, but the trend was similar to the theoretical one. The arching effects measured by the earth pressure cells an embankment heights of 2, 3, 4, 5, and 6 m were 1.05, 1.23, 1.29, 1.28, and 1.29 times greater than those from the theory under the assumption of plain strain. The arching effects from the field test were much greater than those from the theory under the installation of a pile grid.

• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.67-74
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• 2012

The arching effect of the active earth pressure acting on an excavation wall subjected to close excavation reduces lateral earth pressure acting on excavation wall. In this paper, the arching effect was estimated for varying width to excavation depth ratio and wall friction angle by analytical and numerical methods verified with centrifuge test results. The arching effect is significant when the width to excavation depth ratio and wall friction angle is decreased and increased, respectively. The analytical solution derived from the classical arching theory suggested by Handy(1985) shows good agreement with the numerical solution than the other solutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.302-309
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• 2017

The influence of the pile diameter, center to center pile spacing, internal friction angle of embankment soil, and height of embankment on the arching efficacy of the embankment pile was investigated. The arching efficacy, which was derived by the arch model developed in the embankment soil was calculated using two methods, one that considers crown failure of the arch and the other that considers load on the pile cap and critical relative spacing ratio for which the arching efficacy calculated by the two methods are the same. According to the computed results in this study, the arching efficacy calculated from a consideration of the load on pile cap governs when the relative spacing ratio becomes smaller and that calculated from the theory of crown failure governs when the relative spacing ratio becomes larger. The critical relative spacing ratio below which the arching efficacy calculated from a consideration of the load on pile cap governs the design decreases with increasing value, which is defined by the ratio of the pile diameter to the pile center to center spacing. Critical relative spacing ratios, which correspond to the values of 0.5 and 0.2 were 0.35 and 0.85, respectively. Considering the computed results, the critical relative spacing ratio decreases with increasing Rankine passive earth pressure coefficient and critical relative spacing ratios, which correspond to values of 5 and 2, were 0.23 and 0.85, respectively. The arching efficacy, which corresponds to the area ratio of 9%, was 54% and the one that corresponds to the value of 3 was 61%; the critical relative spacing ratios, which correspond to those arching efficacies, were greater than 0.5.

• Journal of the Korean Geotechnical Society
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• v.20 no.6
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• pp.127-136
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• 2004

The soil arching in the backfill, which affects the magnitude and distribution of active earth pressure on a retaining wall, has also an effect on the stability and cross-sectional area of the retaining wall. In this study, results obtained from Paik's equation that includes arching effect on active earth pressure are compared with those from Coulomb theory to investigate the influence of the soil arching on active earth pressure, overturning moment, stability and cross-sectional area of translating rigid retaining walls. The comparisons show that the active forces including arching effects are always higher than those from Coulomb theory, irrespective of $\phi$ and $\delta$ values. The overturning moments, shear force and moment on the rigid wall are also higher when considering arching effects than when not considering arching effects. The deviation of shear forces and moments by including and excluding arching effects becomes maximum at the height of 0.02-0.08 times wall height from the base of the wall. Therefore, if a translating rigid retaining walls is designed based on Coulomb theory, the wall may reach sliding and overturning failures due to arching effect in the backfill and the cross-sectional area of the wall, especially at lower part of the wall, may not be sufficient to resist to shear force and moment.

• Journal of the Korean Geotechnical Society
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• v.26 no.11
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• pp.89-98
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• 2010

A method to design a critical height of embankments is presented so as to mobilize fully soil arching in pile-supported embankments. The behavior of the load transfer of embankment weights on pile cap beams was investigated by a series of model tests performed on pile-supported embankments with relatively wide space between cap beams. The model tests explained that the behavior of the load transfer depended very much on the height of embankments, because soil arching could be mobilized in pile-supported embankments only under enough high embankments. The measured vertical loads on cap beams coincided with the predicted ones estimated by the theoretical equations, which have been presented in the previous studies on the basis of load transfer mechanisms according to either the punching shear failure mode during low filling stage or the soil arching failure mode during high filling stage. The mechanism of the load transfer was shifted beyond a critical height of embankment from the punching shear mechanism to the soil arching mechanism. Therefore, in order to mobilize soil arching in pile-supported embankments, the embankments should be designed at least higher than the critical height. A theoretical equation to estimate the critical height could be derived by equalizing the vertical loads estimated by the load transfer mechanisms on the basis of both the punching shear and the soil arching. The derived theoretical equation could predict very well the experimental critical height of embankment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.131-143
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• 2009

Under transverse earthquake shaking, arching action of bridge structures develops along the deck between the abutments thus providing the so-called deck resistance. The magnitude of the arching action for bridge structures is dependent on the number of spans, connection condition between deck and abutment or piers, and stiffness ratio between superstructure and substructure. In order to investigate the arching action effects for inelastic seismic responses of PSC Box bridges, seismic responses evaluated by pushover analysis, capacity spectrum analysis and nonlinear time-history analysis are compared for 18 example bridge structures with two types of span numbers (short bridge, SB and long bridge, LB), three types of pier height arrangement (regular, semi-regular and irregular) and three types of connection condition between superstructure and substructure (Type A, B, C). The arching action effects (reducing inelastic displacement and increasing resistance capacity) for short bridge (SB) is more significant than those for long bridge (LB). Semi-regular and irregular bridge structures have more significant arching action than regular bridges.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.19-27
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• 2018

Terzaghi proposed a 2D formula for arching based on the assumption of a vertical sliding surface induced in the upper part due to the downward movement of a trapdoor. The formula was later expanded to consider 3D tunnel excavation conditions under inclined sliding surfaces. This study further extends the expanded formula to consider the effects of different ground properties and inclined sliding conditions in the transverse and longitudinal directions considering anisotropic ground conditions, as well as 3D tunnel excavation conditions. The 3D formula proposed in this study was examined of the induced vertical stress under various conditions (ground property, inclined sliding surface, excavation condition, surcharge pressure, earth pressure coefficient) and compared with the 2D Terzaghi formula. The examination indicated that the induced vertical stress increased as the excavation width and length increased, the inclination angle increased, the cohesion and friction angle decreased, the earth pressure coefficient decreased, and the surcharge pressure increased. Under the conditions examined, the stress was more affected at low excavation lengths and by the ground properties in the transverse direction. In addition, The comparison with the 2D Terzaghi formula showed that the induced vertical stress was lower and the difference was highly affected by the ground properties, inclined sliding conditions, and 3D tunnel excavation conditions. The proposed 3D arching formula could help to provide better understanding of complex arching phenomena in tunnel construction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.6
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• pp.417-427
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• 2010

In the ease that a new cross tunnel is constructed under the existing tunnel, development of a longitudinal arching would be influenced by the existing tunnel. But it is not enough to investigate. Especially, the influence of the structure loads on the ground surface on the new tunnel, which the under-passes existing tunnel has been rarely studied. This study, therefore, aimed to clarify the effect of the existing tunnel and the structure on the ground surface on the development of a longitudinal ground arching during the excavation of a cross tunnel under the existing tunnel. Two-dimensional model tests were carried out in the test box, whose dimension was 30 cm (wide) ${\times}$ 113 cm (deep) ${\times}$ 87 cm (high). The existing tunnel was made of S21 steel tube in 16 cm diameter and 1 mm thickness. The ground surface load was 4.9 kPa and was loaded on the model structure in the size with 30 cm width ${\times}$ 16 cm height. New tunnel was excavated in 250 mm height by a bench cut method. As results, the longitudinal arching would be developed but it was severely influenced by not only the existing upper tunnel but also the ground surface load. The influence of the ground surface load on the development of longitudinal ground arching around a new tunnel showed the highest value when the tunnel face located direct under the surface load.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.193-203
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• 2004

Arching effects in backfill materials generate a nonlinear active earth pressure distribution on a rigid retaining wall with rough face, and arching effects on the shape of the nonlinear earth pressure distribution depends on the mode of wall movement. Therefore, the practical shape of failure surface and arching effect in the backfill changed with the mode of wall movement must be considered to calculate accurate magnitude and distribution of active earth pressure on the rigid wall. In this study, a new formulation for calculating the active earth pressure on a rough rigid retaining wall rotating about the base is proposed by considering the shape of nonlinear failure surface and arching effects in the backfill. In order to avoid mathematical complexities in the calculation of active earth pressure, the imaginary failure surface composed of four linear surfaces is used instead of the nonlinear failure surface as failure surface of backfills. The comparisons between predictions from the proposed equations and existing model test results show that the proposed equations produce satisfactory predictions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1271-1276
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• 2006

Vertical loads acting on corrugated metal culverts under negative arching condition were investigated through numerical analyses. Four kinds of corrugated metal culverts with span of 3m were considered in numerical analyses. Also, depths of cover were varied from 1m to 6m with increment of 1m. According to numerical analyses, magnitudes of vertical loads acting on culverts under the condition of negative arching were similar as overburden load on culvert. Furthermore, magnitudes of vertical loads acting on culverts supported by pile foundation were similar as those without pile foundation when depths of cover were less than about 2m. For larger depths of cover which are greater than about two times of span of culvert, magnitudes of vertical loads were slightly larger than those without pile foundation and its tendency becomes more clear as flexural rigidity of corrugated metal increases.