• Journal of the Korean Geotechnical Society
• /
• v.17 no.6
• /
• pp.207-213
• /
• 2001

Shaking table tests to investigate the dynamic friction behavior of interfaces between dense dry granular soils and construction material(concrete) were performed and the results are reported. The results show the variation of dynamic interface friction coefficients between dense dry granular soils and construction material was small in the sliding velocity range employed in this study. It was also observed that dynamic interface friction coefficients decreased as mean grain sizes of granular soils increased. These coefficients were compared with the friction coefficients obtained from the peak internal friction angles of the same granular soils by plane strain compression tests.

• Geotechnical Engineering
• /
• v.7 no.2
• /
• pp.5-26
• /
• 1991

The results of a laboratory investigation for the influence of soil sties history, relative density of sand, pile surface condition depth and diameter on the behavior of piles in uplift are presented. Ultimate Uplife capacity depends not only on the relative density of sand but soil horizontal stress. The phenomena of critical depth can be explained by change of horizontal stress with depth. The value of Ktan tends to decreases with increasing pile diameter.

• Geomechanics and Engineering
• /
• v.6 no.4
• /
• pp.341-358
• /
• 2014

Uplift response of rectangular anchor plates has been investigated in physical model tests and numerical simulation using Plaxis. The behavior of rectangular plates during uplift test was studied by experimental data and finite element analyses in cohesionless soil. Validation of the analysis model was also carried out with 200 mm and 300 mm diameter of rectangular plates in sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 200 mm and 300 mm computed maximum displacements were excellent for rectangular anchor plates. Numerical analysis using rectangular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in dense and loose packing of cohesionless soil.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.139-146
• /
• 2001

Undrained triaxial tests were peformed for a weathered soil, which includes local measurement using LVDT The behavior from small In large strain conditions could be evaluated consistently through a triaxial test, The stress-strain relationship of undisturbed samples were compared with the disturbed and the shear moduli in the small strain level had the almost same values. Especially the shear moduli were mostly affected by the initial condition of water contents. An anisotropic hardening model based on the total stress concept could predict the stress-strain relationship accurately, which makes it possible to analyze the geotechnical problem reasonably for the weathered soil.

• Geotechnical Engineering
• /
• v.12 no.5
• /
• pp.55-62
• /
• 1996

Lateral loading model tests were performed on the rigid box-shaped cellular bulkhead by displacement-controlled method. The materials of ground and fill used in this study are two aluminium rods with different sections. The behalf·iotas of ground and fill were recorded by photo/video techniques and failure mechanism created in ground and fill has been simulated two-야mensionally. Also the theoretical consideration about the test results was done on the basis of Hansen's earth pressure theory. As a result, the shape of sliding face the location of sliding face and the loading height was also investigated.

• Journal of the Korean Geotechnical Society
• /
• v.16 no.6
• /
• pp.153-160
• /
• 2000

본 연구는 과제하중의 재하폭과 재하위치를 매개변수로 변화시켜 옹벽의 뒤채움재 상부 지표면에서 제한폭의 과재하중작용시 그의 활동거동에 관한 실험적, 수치적 해석적 연구이다. 중력 수준을 1g, 20g,40g로 변화시켜 수행한 원심모형실험을 통해 구한 기초의 극한지지력 및 하중-침하특성, 하중-옹벽수평변위특성에 관하여 조사연구 하였다. 또한, 옹벽의 활동으로 인한 지반파괴의 영향을 받기 시작하는기초의 재하위치를 추정하기 위하여 종래의 얕은 기초의 극한지지력 실험을 수행하여 이들 결과와 함께 비교하였다. 한편, 모형실험결과와 기존의 이론식을 수정보완한 해석 결과와 비교분석하였다.

• Geomechanics and Engineering
• /
• v.5 no.4
• /
• pp.313-329
• /
• 2013

Vetiver grass (Vetiveria zizanioides) is being effectively used in many countries to protect embankment and slopes for their characteristics of having long and strong roots. In this paper, in-situ shear tests of the ground with the vetiver roots have been conducted to investigate the stabilization properties corresponding to the embankment slopes. Numerical analyses have also been performed with the finite element method using elastoplastic subloading $t_{ij}$ model, which can simulate typical soil behavior. It is revealed from field tests that the shear strength of vetiver rooted soil matrix is higher than that of the unreinforced soil. The reinforced soil with vetiver root also shows ductile behavior. The numerical analyses capture well the results of the in-situ shear tests. Effectiveness of vetiver root in geotechnical structures-strip foundation and embankment slope has been evaluated by finite element analyses. It is found that the reinforcement with vetiver root enhances the bearing capacities of the grounds and stabilizes the embankment slopes.

• International Journal of Railway
• /
• v.3 no.4
• /
• pp.117-122
• /
• 2010

In transportation geotechnical engineering, stress-strain behavior of earth structures has been analyzed by numerical simulations with the implemented plasticity constitutive model. It is a fact that many advanced plasticity constitutive models on predicting the mechanical behavior of soils have been developed as well as experimental research works for geotechnical applications in the past decades. In this study, recently developed, a unified constitutive model for both clay and sand, which is referred to as CASM (clay and sand model), was compared with a classical constitutive model, Cam-Clay model. Moreover, integration methods of stress-strain rate equations using CASM were presented for simulation of undrained and drained triaxial compression tests. As a conclusion, it was observed that semi-implicit integration method has more improved accuracy of capturing strain rate response to applied stress than explicit integration by the multiple correction and iteration.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.717-724
• /
• 2002

To investigate the behavior of air-shaft and existing tunnel by excavating the small-diameter shaft into the existing tunnel, prototype air-shaft was constructed and analyzed in this study. Geotechnical characterization was conducted by boring and rock cores obtained were tested in the laboratory. Field monitoring including radial and tangential stresses and displacements was conducted with the 3-dimensional numerical analysis of prototype air-shaft. Results of field monitoring were compared with the numerical results. The results showed that maximum displacement of 2.11mm and maximum tangential stress of 54.0 kg/$\textrm{cm}^2$ were obtained during shaft excavation near the right shoulder of the existing tunnel. The comparison of these field measurements with 3-dimensional numerical analysis showed that much more higher stress was measured during excavation compared to the numerical results even though the trends of stress and displacement were similar.

• Journal of the Korean Geotechnical Society
• /
• v.16 no.5
• /
• pp.37-43
• /
• 2000

보통으로 다져진 실트질 모래(Dr=50%)에 대한 액상화 전후 상태에서의 반복하중에 의한 동적거동을 연구하기 위하여 몇가지의 압밀응력비로서 압밀시킨공시체에 대해서 일련의 일련의 반복삼축시험을 수행하였다. 연구결과로서 압밀응력비가 액상화거동에 미치는 영향을 나타내었으며 또한 액상화 전후의 동적거동을 비교하였다. 그리고 액상화 후의 거동은 선행액상화시의 응력반전여부에 의해서 절대적으로 좌우된다는 사실을 보여주고 있다. 결론적으로 액상화를 경험한 공시체의 액상화저항은 액상화를 경험하지 않은 공시체에 비해서 이방압밀의 경우에는 높고 등방압밀의 경우에는 낮다.