• Journal of the Korean Geotechnical Society
• /
• v.18 no.3
• /
• pp.105-112
• /
• 2002

Increases in excess pore water pressure without change of surcharge load were reported in clay underneath embankment at Berthierville and Olga sites after the end of construction. These abnormal phenomena could not be explained by classical consolidation theory. This paper presents a nonlinear viscoplastic model to interpret an increase in pore water pressure on natural clay, The proposed model can consider the combined processes of pore water pressure dissipation according to Darcy's law and pore water pressure generation due to viscoplastic strain, as well as time-dependent viscoplastic behaviour and strain rate dependency of preconsolidation pressure. The calculated results using numerical analysis are compared with measured ones under embankments built on soft clay at Berthierville and Olga in Quebec, Canada. It may be possible to explain the phenomenon of excess pore water pressure increase after the end of construction using the proposed nonlinear viscoplastic model.

• Geotechnical Engineering
• /
• v.4 no.1
• /
• pp.49-58
• /
• 1988

The stresses on the buried steel pipe under embankment are analysed by the elasto-plastic theory using FEM to study the influences of the geometry of soil-conduit pipe system and the elastic modulus of the fill on the pipe responses . The geometry of the system considered in this study includes the height of embankment, the thickness of the pipe, and the width and the depth of the trench . By comparing the stresses computed by Marston-Spangler's pipe theory with those obtained from the elasto-plastic theory, Marston-Spangler's theory was discussed and analysed . It is found that the stress distribution around the pipe by elasto- plastic analysis is similar to that by Spangler's flexible pipe theory when the geometrical ratio (diameter/thickness) of the steel pipe is 400. And Spangler's flexible pipe theory does not seem to be suitable to analyse the buried steel pipe of which the geometrical ratio is lower than 200. The vertical loads by the rigid pipe theory are always larger than those by the flexible pipe theory regardness of the variations in the geometry of soil-conduit pipe system considered above and the elastic modulus of the fill.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.2
• /
• pp.13-23
• /
• 2019

In this study, an overtopping model experiments and three dimensional seepage characteristics at the deteriorated homogeneous reservoirs were performed to investigate the behavior of failure for embankment and spillway transitional zone due to overtopping. The failure pattern, pore water pressure, earth pressure and settlement by overtopping were compared and analyzed. The pattern of the failure by overtopping was gradually enlarged towards reservoirs crest from the spillway transition zone at initial stage. In the rapid stage and peak stage, the width and depth of failure gradually increased, and the pattern of the failure appeared irregular and several direction of the erosion. In the early stage, the pore water pressure at spillway transitional zone was more affected as its variation and failure width increased. In the peak stage, the pore water pressure was significantly increased in all locations due to the influence of seepage. The earth pressure increased gradually according to overtopping stage. The pore pressure by the numerical analysis was larger than the experimental value, and the analysis was more likely to increase steadily without any apparent variation. The horizontal and vertical displacements were the largest at the toe of slope and at the top of the dam crest, respectively. The results of this displacement distribution can be applied as a basis for determining the position of reinforcement at the downstream slope and the crest. The collapse in the overtopping stage began with erosion of the most vulnerable parts of the dam crest, and the embankment was completely collapsed as the overtopping stage increased.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.1210-1224
• /
• 2009

The present paper illustrates the outcome of the monitoring of the consolidation behavior of a soft foundation soil under a large submerged sand embankment. Measurements of settlements and excess pore water pressures showed a good agreement with predictions evaluated using the large strain consolidation theory. Soft soil improvement by means of deep mixing has been optimized. Moreover, the principles and developments of underwater geosynthetics applications are discussed.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.6
• /
• pp.131-142
• /
• 1999

The objective of this study is to perform finite element analyses using the anisotropic hardening constitutive model on the basis of the total stress concept. An anisotropic hardening constitutive model had been developed in a companion paper, and was then formulated by implicit stress integration and consistent tangent moduli. A nonlinear finite element analysis program was coded including the algorithm, and as a result, the nonlinear solution was accurately calculated and converged to be asymptotically quadratic. In the analysis of a test embankment it was found that the proposed model could predict the displacement of soils more reasonably than the analysis with von Mises type model. In addition the proposed model could predict accurately the actual behavior through the reanalysis of the problem by a reasonable evaluation of the strength parameter.

• The Journal of Engineering Research
• /
• v.6 no.1
• /
• pp.83-96
• /
• 2004

A soil mailed wall is adapted as road widening measure and is constructed under a miniature abutment built on steel pipe piles. The soil nailed wall called for removal of the existing embankment slope to permanently retain the fill behind the abutment. The soil nailed wall is fully instrumented and is monitored. A 3D finite element analysis is used to study further the behavior of the soil nailed wall. The complete sequence of construction is simulated. The numerical model is calibrated against the instrumented nailed wall. Then a parametric study is conducted. The results provide valuable information related to the effect of the excavation and nailing on the following: axial load and bending moment in the piles, load in the nails, and wall deflections.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.924-931
• /
• 2005

In this study, we intended to compare and examine several settlement management methods by analyzing measurement results of a site of the industrial complex at ${\bigcirc}{\bigcirc}$ province. We predicted and analyzed the amount of final settlement by using generally used final settlement methods as like Hyperbola method, Hoshino methods and Asaoka method. And then, We compared the predicted results with that of measurement. On the basis of comparison of the three methods, Hyperbola method was the most convenient and accurate method of the three methods and if a sufficient time was given enough after embankment construction, the use of Hoshino method was possible. In the case of the Asaoka methods, it was possible to know that it had an approaching tendency to the measured one with increasing time interval spent on analysis. Therefore, in order to predict settlement behavior more accurately it is needed to understand their advantages and shortcomings sufficiently and pay attention to application to the real site.

• Geotechnical Engineering
• /
• v.14 no.1
• /
• pp.15-28
• /
• 1998

The use of EPS application to construction field was introduced in this country very recently. Nevertheless, approximately a total of 210,000m3 of EPS application was conducted in less than four years. Main app.lication areas for the EPS method are : (1)backfill behind a bridge abutment constructed on soft clay soil, (2)embankment constructed on soft clay soil, and (3)backfill of gravity wall. Among these, about 70oA of EPS are used for (1) and (2) deb cribed above. In this study, an invesitgation was held for the application of the EPS method to backfill of a bridge abutment which was constructed on soft clay soil. Several instruments were installed around the construction site to invesitgate the behavior of the system. Then a Finite Element Analysis was conducted for comparison.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.21 no.5
• /
• pp.255-264
• /
• 2017

Dynamic numerical simulation of pile-supported slab track system embedded in a soft soil and embankment was performed. 3D model was formulated in a time domain to consider the non-linearity of soil by utilizing FLAC 3D, which is a finite difference method program. Soil non-linearity was simulated by adopting the hysteric damping model and liner elements, which could consider soil-pile interface. The long period seismic loads, Hachinohe type strong motions, were applied for estimating seismic respose of the system, Parametric study was carried out by changing subsoil layer profile, embankment height and seismic loading conditions. The most of horizontal permanent displacement was initiated by slope failure. Increase of the embedded height and thickness of the soft soil layer leads increase of member forces of PHC piles; bending moment, and axial force. Finally, basic guidelines for designing pile-supported slab track system under seismic loading are recommended based on the analysis results.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.12
• /
• pp.43-52
• /
• 2007

This study analyzes the characteristics of creep deformation behavior of weathered granite soils used in road embankments. The creep strain under the unconfined compressive state demonstrated an excellent agreement with the theoretical analysis of the burgers substance. The elastic deformation showed a termination in its characteristics after a long-term period owing to the increase in applied loads. The primary creep strain was 0.0028 and concluded that the deformation completed within $3{\sim}5$ days after applying the loads. Also, the completing time of creep deformation in the embankment soils increased in proportion to the height of embankment soils. The secondary creep strain is about 50% of the primary creep strain.