• Geomechanics and Engineering
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• 제13권4호
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• pp.653-669
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• 2017

By increase in the population and consequently constructions, new structures may be built in vicinity of the soil slopes. Such structures can be regarded as an extra surcharge on the slopes. The intensity and location of the surcharge affects the displacements of the slopes. Few researchers have studied the effect of surcharge on displacements of soil slopes. In this research, using limit analysis method and upper bound theory with non-associated flow rule, displacements of soil slopes in vicinity of a surcharge has been estimated. The authors have improved the technique previously proposed by them and a new formulation is suggested for calculating the permanent displacements of the soil slope in presence of a surcharge for two failure modes, rotational and transitional. A comparison has also been made between the two mentioned modes for various conditions of surcharge and slope. The conditions resulting in the rotational mode to be more critical than the transitional mode have been investigated. Also, the effects of surcharge's intensity, location of surcharge as well as the soil properties have been investigated.

• Geomechanics and Engineering
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• 제23권1호
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• pp.71-83
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• 2020

Cantilever sheet pile walls are subjected to surcharge loading located on the backfill soil and at different distances from the top of the wall. The response of cantilever sheet pile walls to surcharge loadings at varying distances under seismic conditions is scarce in literature. In the present study, the influence of uniform surcharge load on cantilever sheet pile wall at varying distances from the top of the wall under seismic conditions are analyzed using finite difference based computer program. The results of the numerical analysis are presented in non-dimensional form like variation of bending moment and horizontal earth pressure along the depth of the sheet pile walls. The numerical analysis has been conducted at different magnitudes of horizontal seismic acceleration coefficient and vertical seismic acceleration coefficients by varying the magnitude and position of uniform surcharge from the top of the wall for different embedded depths and types of soil. The parametric study is conducted with different embedded depth of sheet pile walls, magnitude of surcharge on the top of the wall and at a distance from the top of the wall for different angles of internal friction. It is observed that the maximum bending moment increases and more mobilization of earth pressure takes place with increase in horizontal seismic acceleration coefficients, magnitude of uniform surcharge, embedded depth and decrease in the distance of surcharge from the top of the wall in loose sand.

• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1225-1256
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• 2014

Calculating the seismic displacement of retaining walls has an important role in the optimum design of these structures. Also, studying the effect of surcharge is important for the calculation of active pressure as well as permanent displacements of the wall. In this regard, some researchers have investigated active pressure; but, unfortunately, there are few investigations on the seismic displacement of retaining walls with surcharge. In this research, using limit analysis and upper bound theorem, permanent seismic displacement of retaining walls with surcharge was analyzed for sliding and overturning failure mechanisms. Thus, a new formulation was presented for calculating yield acceleration, critical angle of failure wedge, and permanent displacement of retaining walls with surcharge. Also, effects of surcharge, its location and other factors such as height of the wall and internal friction angle of soil on the amount of seismic displacements were investigated. Finally, designing charts were presented for calculating yield acceleration coefficient and angle of failure wedge.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.25-32
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• 2000

In order to analyze the behavior of piled abutment adjacent to surcharge loads a numerical study was conducted. In 2D plane stalin analysis, the distribution of lateral soil movement was investigated by varying the thickness of clay layer and the magnitude of surcharge loads. In 3D analysis, the magnitude and distribution of lateral pile-soil movement were studied for different cap rigidity. Based on limited parametric studies, a simple method is proposed to identify the lateral pressure of piled abutment adjacent to surcharge loads.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.481-488
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• 1999

This study, investigates the existing theoretical backgrounds in order to examine the behavior of lateral flow owing to the plasticity of soils when unsymmetrical surcharge is worked on polluted soils by the increase of water content compares and analyzes the results measured through model tests. Unsymmetrical surcharge is increased at regular intervals to soil tank made up the polluted soils and then the amounts of settlement, lateral displacement and upheaval are observed. Critical surcharge was decided ｑ$\sub$cr/= 3.42 C$\sub$u/ similar to those had proposed Terzaghi and JHI, and the value of ultimate capacity was decided ｑ$\sub$ult/= 7.71 C$\sub$u/ similar to that of Tschebotarioff and JHI.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.79-86
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• 2000

Recently, application of the reinforced earth wall is in increasing trend. Although many investigations on the influence of the length and spacing of reinforcement and the values of surcharge load has been carried out in the past, but the research about the influence of the location and value of surcharge loads has been scarce. Therefore this study was necessitated. The model test were carried out by varying the location and value of surcharge loads for two types of the backfill soils.

• Geomechanics and Engineering
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• 제6권6호
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• pp.517-530
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• 2014

Seismic ground response analysis is one of the most important issues in geotechnical earthquake engineering. Conventional seismic site response and free field analysis of layered soils does not consider the effect of surcharge mass which may be present on the top layer. Surcharge mass may develop extra inertial force to the soil and, hence, significantly affect on the results of seismic ground response analysis. Methods of analysis of ground response may also be categorized into time domain and frequency domain concepts. Simplicity in developing analytical relations and accuracy in considering soil dynamic properties dependency to loading frequency are benefits of frequency domain analysis. In this part of the paper, seismic ground response is analyzed using transfer function method for soil layers considering surcharge mass on the top layer. Equation of motion, wave equation, is solved using amended boundary conditions which effectively take the impact of surcharge mass into account. A computer program is developed by MATLAB software based on the solution method developed for wave equation. Layered soils subjected to earthquake loading were numerically studied and solved especially by the computer program developed in this research. Results obtained were compared with those given by DEEP SOIL computer program. Such comparison showed the accuracy of the program developed in this study. Also in this part, the effects of geometrical and mechanical properties of soil layers and especially the impact of surcharge mass on transfer function are investigated using the current approach and the program developed. The efficiency and accuracy of the method developed here is shown through some worked examples and through comparison of the results obtained here with those given by other approaches. Discussions on the results obtained are presented throughout in this part.

• 한국방재학회 논문집
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• 제5권4호
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• pp.49-57
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• 2005

본 연구에서는 상재하중을 적용한 굴착모형실험을 통하여 상재하중 적용으로 인한 굴착단계별, 벽체강성 및 지반조건에 따른 토류벽체의 수평변위, 배면지반 지표침하, 토류벽체에 적용되는 토압변화 및 분포에 대하여 실험결과치, 이론치 및 현장자료 분석치와 상호비교, 분석하여 상재하중 적용에 의한 영향을 규명하였다. 그 결과 상재하중이 적용된 모형지반에서의 지표침하곡선 형태는 상재하중 미 적용시 지표침하 곡선형태의 정규확률 분포곡선과 달리 상재하중 중앙 부분이 최대 침하를 일으키는 포물선 형태의 침하를 보이고 있으며, 굴착단계별 상재하중 적용으로 인한 벽체최대수평변위는 최종굴착시에 0.8H(보:굴착깊이) 지점에서 벽체의 최대수평변위가 발생하였으며, 상재하중 적용에 따른 벽체변위량의 증가범위는 벽체상부로부터 하중이격거리에 2배의 깊이까지 증가범위를 보였다. 또한, 굴착단계별 지표면의 침하로 인한 기초판의 각 변위는 최종단계에서의 각 변위가 가장 크게 발생하였고, 벽체강성별로는 두께 4mm(유연계수 ${\rho}\;:480m^3/t$) 벽체가 두께 9mm(유연계수 ${\rho}\;: 40m^3/t$)보다 최대 3배 이상 발생하고 있어 벽체강성의 영향이 매우 큼을 알 수 있다.

• Geomechanics and Engineering
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• 제7권5호
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• pp.525-537
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• 2014

The typical design of ground improvement with prefabricated vertical drains (PVD) and surcharge preloading involves a series of deterministic analyses using averaged or mean soil properties for the various combination of the PVD spacing and surcharge preloading height that would meet the criteria for minimum consolidation time and required degree of consolidation. The optimum design combination is then selected in which the total cost of ground improvement is a minimum. Considering the variability and uncertainties of the soil consolidation parameters, as well as considering the effects of soil disturbance (smear zone) and drain resistance in the analysis, this study presents a stochastic cost optimization of ground improvement with PVD and surcharge preloading. Direct Monte Carlo (MC) simulation and importance sampling (IS) technique is used in the stochastic analysis by limiting the sampled random soil parameters within the range from a minimum to maximum value while considering their statistical distribution. The method has been verified in a case study of PVD improved ground with preloading, in which average results of the stochastic analysis showed a good agreement with field monitoring data.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.838-845
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• 2005

Slope stability analyses have been carried out to investigate surcharge loading effects. Finite Element Analysis (FEA) involves the stress-strain behaviour of soils achieving reasonably accurate and useful results of slope stability analysis. Therefore, in this study, one of well known FEA programs, SIGMA/W, has been used to do slope stability analyses with respect to various upper slope angles and surcharge loadings. Factor of Safety(FS) exponentially decreases and significantly good correlation with the increased slope angle for upper slopes. As the surcharge loading increases from 10 t/m to 90 t/m for nail-reinforced slopes, the FS in fully saturated condition decreases from 42% to 47% and from 17% to 25% for relatively low and high strength of soils, respectively, than in dry condition.