• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.425-433
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• 2019

In this study, a simple method of calculating the passive earth pressure coefficient, which is based on the limit equilibrium method, was proposed and the calculated earth pressure coefficients were compared with those of several researchers. The angle of the linear failure surface, which is combined with the logarithmic spiral arc, to the failure surfaces of the passive zone was derived and the whole passive thrust acting on the Rankine passive zone was considered in the proposed method instead of considering the horizontal component of passive thrust. The variations of the passive earth pressure coefficients of the proposed method showed the same tendency as that of the Coulomb's passive earth pressure coefficients with an inclined angle of backfill and internal friction angle. The magnitude of passive earth pressure coefficients of the proposed method were smaller than those of the Coulomb in almost all cases. A comparison of the passive earth pressure coefficients with the wall friction angle revealed the passive earth pressure coefficients of the proposed method to be smaller than those of the Coulomb and the differences between the two values increased with increasing internal friction angle and wall friction angle. A comparison of the passive earth pressure coefficients of the proposed method with those of the existing researchers for the considered internal friction angles of $25^{\circ}$, $30^{\circ}$, $35^{\circ}$, and $40^{\circ}$ and three wall friction angles revealed the maximum percentage differences for the Kerisel and Absi method, Soubra method, Lancellotta method, $Ant\tilde{a}o$ et al. method, Kame method, and Reddy et al. method to be 4.8%, 3.8%, 31.1%, 4.0%, 20.6%, and 12.8% respectively. The passive earth pressure coefficient and existing pressures were similar in all cases.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.117-129
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• 2009

Several researches have been done to estimate the earth pressure on a vertical circular shaft considering three dimensional arching effect and verified them by conducting model tests. However, any equation suggested so far is not applicable in case of multi-layered soils and/or C-${\phi}$ soils. In this study, new equation for estimating the earth pressure acting on the vertical shaft in c-${\phi}$ soils is proposed. A parametric study is performed to investigate the significance of the cohesion when estimating the coefficient of earth pressure in C-${\phi}$ soils and estimating earth pressures in vertical shafts. A method which can estimate the earth pressure on vertical shafts in layered soils is also proposed by assuming a failure surface in layered soils and using the modified equation. This paper is Part I of companion papers focusing on the theoretical aspect of model developments; the experimental verification will be made in Part II.

• Journal of the Korean Geotechnical Society
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• v.21 no.8
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• pp.85-93
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• 2005

Earth pressures acting on unmovable rigid walls vary according to loading-unloading conditions due to compaction experienced by backfill soil. Appropriate coefficients of earth pressure at rest with considering this influence need to be determined to estimate earth pressures more reasonably.0 this study, a single cycle hysteretic model simulating soil's loading-unloading-reloading behavior under $K_o-condition$ was reproduced by conducting a series of $K_o-triaxial$ test for compacted residual soils. Based on the results, coefficients of earth pressure at rest at each stage of stress paths such as, virgin loading, unloading and reloading were determined. Also, applicabilities of empirical equations to the estimation of the coefficients were evaluated by comparing the experimental results with those estimated by the equations. As a result, it was concluded that the empirical equations could be applied reasonably to the estimation of the coefficients for compacted residual soils in cases where some amount of error might be acceptable for the reloading stage of the hysteretic model.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.83-95
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• 2017

This study examined the magnitude and distribution of earth pressure on the excavation wall in jointed rock mass by considering different groundwater conditions under various rock types, joint inclination angles, and earth pressure coefficients. Based on a physical model test (Son and Park, 2014), extended studies were conducted considering rock-structure interactions based on the discrete element method, which can consider the joints characteristics of rock mass. The results showed that the earth pressure was highly influenced by the groundwater condition as well as the rock type, joint inclination angle, and earth pressure coefficient. The results were also compared with Peck's earth pressure for soil ground, and clearly showed that the earth pressure in jointed rock mass can be greatly different from that in soil ground.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.157-168
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• 2000

토류구조물의 안정문제로는 장단기적으로 정적인 경우와 동적인 경우, 그리고 지반의 동적 거동특성, 흙의 강도저하 등을 미리 파악하여 기술적인 대처를 할 필요가 있을 것이다. 본 연구에서는 실내 모형 실험을 통하여 구조물의 배면에 토성이 다른 일반모래, 표준모래, 점성토를 뒷채움하여 다짐없이 강사만 하고, 룰러다짐, 진동다짐을 하여 토피의 수평 진동거리를 길게, 짧게 그리고 중간으로 하여 강성벽체에 작요？는 수평토압에 대한 정적, 동적 특성을 규명하는 것이다. 모형 실험장치로는 실험대, 토조, 토압측정장치, 진동하중 발생장치, 진동측정장치, 강사기, 롤러 등을 설치하여 거리에 따른 병진운동으로 가속도와 수평토압, 수평토압계수, 전체토압, 토압의 작용점, 지진토압증분 증을 구하여, 실험결과와 기존 이론결과, 그리고 유한요소 해석결과와 비교 고찰하였다.

• Geotechnical Engineering
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• v.9 no.4
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• pp.7-16
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• 1993

Calibration chamber tests were conducted on open -ended model piles driven into dried siliceous sands with different soil conditions in order to clarify the effect of soil conditions on plug capacity, The model pile used in the test series was devised so that the bearing capacity of an open -ended pile could be measured out into three components , outside shaft resistance. plug resistance and tip resistance. Under several assumption, the value of earth pressure coefficient in the soil plug is calculated. It is gradually reduced with increase in the longitudinal distance from the pile tip. At the bottom of soil plug, it tends to decrease with increase in the penetration depth and relative density, and to increase with the increase of ambient pressure. In comparison of measured and calculated plug capacities using the one -dimensional analysis, we note that API code and one -dimensional analysis combined with P suggested by Randolph et al. and O'Neill et al. result in great underestimation of the plug capacity. Therefore, based on the test results, an empirical equation was suggested to compute the earth pressured coefficient to be used in the calculation of plug capacity using the one -dimensional analysis. and it produces proper plug capacities for all soil conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.1
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• pp.65-72
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• 1983

Dry sand specimens for both normally consolidated and overconsolidated triaxial compression tests were prestressed on the path with five different coefficients of earth pressure 1.0, 3/4, 0.55, $K_0$ and 1/3. Deformation resistance of normally consolidated sand increased with increasing the initial stress for all coefficients of earth pressure during consolidation, and the deformation modulus at a certain initial stress showed a tendency to increase with increasing the coefficient of earth pressure. And deformation moduli($E_i$, $E_{50}$), were found to be proportional to the $n_{th}$ power of initial stresses[${\sigma}_{m0}{^{\prime}}$, ${\sigma}_{10}{^{\prime}}$, ${\sigma}_{30}{^{\prime}}$, $({\sigma}_1-{\sigma}_3)_0$] for both isotropically and anisotropically normally consolidated samples, where n varied from 0.37 to 0.92. Overconsolidated sand with the higher overconsolidation ratio showed the higher deformation modulus. It is concluded that the $K_0$-anisotropically consolidated triaxial compression test is necessary to obtain the more accurate value of in-situ deformation modulus.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.179-193
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• 1994

In the development of engineering designs, decisions are required irrespective of the state of completeness and quality of information, and are formulated under conditions of uncertainty. Furthermore, under conditions of uncertainty the design invokes risks. Thus, in the design of the structures, the currently used deterministic design method does not provide a realistic assessment of the actual safety or the reliability of the structures. It is desirable that decisions required in The process of the design invariably must be made based on the reliability analysis. Properties of soil material are subject to more uncertainty than those of other structural material. In the field of soil mechanics and foundation engineering, it needed to develop reliability-based design methods. In order to simplify the reliability analysis or the reliability-based design process of the structures associated with the active earth pressure, it is necessary to find the variation and the distribution type of the active earth pressure calculated from the basic properties of soils. Monte Carlo simulation is performed to obtain the relationship between the variation of the active earth pressure for cohessionless soils calculated by using Rankine formula and the basic soil properties and the distribution type of the earth pressure. A series of regression equations obtained by utilizing the multi-linear regression analysis is suggested in this paper and the sensitivity of the basic soil properties to the variation of The earth pressure is investigated. The type of distribution of the active earth pressure was found to be the beta distribution in most cases or to be very similar to the beta distribution, if the basic soil variables are normally distributed.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.55-65
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• 2002

Model tests were performed to investigate the mechanism of lateral earth pressure on a buried pipe, which was installed in a plastic flowing soil mass undergoing lateral movement. On the basis of failure mode tests, the equation of lateral earth pressure to apply Maxwell's visco-elastic model was proposed to consider the soil deformation velocity. Through a series of model tests of differential soil deformation velocity, lateral earth pressure of theoretical equation was compared with experimental results. When lateral soil movement was raised, the lateral earth pressure acting on buried pipe increases linearly with the soil deformation velocity. It shows that the lateral earth pressure on buried pipe is largely affected by soil deformation velocity. When plastic soil movement was raised, lateral earth pressure predicted by theoretical equation showed good agreement with experimental results. Also, coefficient of viscosity by theoretical equation had a good agreement with direct shear test results.

• Journal of Ocean Engineering and Technology
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• v.13 no.2 s.32
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• pp.159-167
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• 1999

For exisiting $K_0$-oedometer, the lateral wall of the ring is cut thinly to make space and by filling the space with space with water or mercuty to keep the balance to the lateral pressure of a specimen, the pressure of the fluid is checked for the pressure of the specimen. But the devices to keep the balance to the lateral pressure of a specimen are complicated, difficult to manufacture and expensive. As newly developed $K_0$-oedometer is equipped with the load cell which can resist higher pressute than the lateral pressure of the specimen, there is nearly no deformation due to the lateral pressure of the specimen. And the measuting is cheap and easy as there are fewer accessories.