• Computational Structural Engineering
• /
• v.4 no.4
• /
• pp.5-9
• /
• 1991

일반적으로 구조물의 내진설계는 강지진시 구조물의 비탄성 거동에 의존함으로써 비탄성 변형으로 인한 구조요소의 점진적인 파괴와 상당한 층간변위가 초래된다. 또한 구조물이 지반가속도를 증폭시키는 역할을 함으로써 구조물내의 각종 설비와 비구조체에 큰 피해를 초래할 수도 있다. 따라서 강지진시 지반으로부터 상부 구조물에 전달되는 지진하중 자체를 감소시킴으롯써 구조물의 응답 가속도를 적게 하여 구조물과 구조물내의 설비, 비구조체를 지진으로부터 보호하기 위한 새로운 내진설계방법으로 지반 분리 시스템이 연구개발되어 실용화되고 있다. 본 고에서는 지반 분리 시스템의 기본개념과 특성 및 실용현황에 대하여 살펴보기로 한다.

• Geotechnical Engineering
• /
• v.39 no.6
• /
• pp.55-65
• /
• 2023

• Geotechnical Engineering
• /
• v.40 no.1
• /
• pp.36-42
• /
• 2024

• Journal of the Korean Geotechnical Society
• /
• v.17 no.1
• /
• pp.15-24
• /
• 2001

흙필터는 일반적으로 침식이나 파이핑으로부터 지반 구조물을 보호하기 위하여 사용된다. 세립자들이 유동하여 필터에 퇴적하는 폐색현상이 발생하는 경우, 간극수압이 증가하고 이로 인해 지반구조물의 불안정을 유발시키게 된다. 미세입자의 유동에 의한 폐색현상은 옹벽의 뒤채움재에 설치한 필터, 흙댐의 저부에 설치된 필터, 그리고 터널의 라이닝 뒤에 설치한 필터 등에서 발생할 수 있다. 폐색현상은 필터의 투수능을 저하시켜 배수능력에 상당한 위험을 초래할 수 있다. 본 연구에서는 필터의 폐색으로 인한 투수능 저하 정도를 실험을 통해 관찰하고 이론적인 모델을 통해 정량화 시키고자 하였다. 일정한 농도의 현탁액이 필터로 유입되는 분리형 실험과 현장상태를 모사하는 흙-필터 시스템의 결합형 실험을 통해 투수능의 저하현상이 압력 제어조건과 유량 제어조건에서 관찰되었고, 서로 비교 분석되었다. 미세입자가 통과하는 필터의 간극을 모세관으로 가정한 후 모세관에서 유체의 흐름 원리를 이용하여 물리적인 폐색에 의해 발생하는 투수능 저하현상을 이론적인 모델로 구성하였다. 일반적으로 투수능은 1/10 수준으로 감소되었으며, 분리형 실험에 의한 결과와 이론적인 모델의 결과는 잘 일치하였다. 또한, 결합형 실험결과와 분리형 실험결과가 비교적 잘 일치하여 투수능 저하예측은 분리형 실험이나 이론적 모델에 의하여 가능하리라 판단되었다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.4
• /
• pp.319-327
• /
• 2017

In this study, characteristics of seismic behaviors of offshore wind turbine systems using concrete-suction-type supporting structures are investigated. Applying hydrodynamic pressure from the surrounding sea water and interaction forces from the underlying soil to the structural system which is composed of RNA, the tower, and the supporting structure, a governing equation of the system is derived and its earthquake responses are obtained. It can be observed from the analysis results that the responses are significantly influenced by soil-structure interaction because dynamic responses for higher natural vibration modes are increased due to the flexibility of soil. Therefore, the soil-structure interaction must be taken into consideration for accurate assessment of dynamic behaviors of offshore wind turbine systems using concrete-suction-type supporting structures.

• Journal of the Korean Geotechnical Society
• /
• v.37 no.11
• /
• pp.119-129
• /
• 2021

The process of constructing the DB in the current geotechnical information DB system needs a lot of human and time resource consumption. In addition, it causes accuracy problems frequently because the current input method is a person viewing the PDF and directly inputting the results. Therefore, this study proposes building an automatic digital DB using AI (artificial intelligence) of boring logs. In order to automatically construct DB for various boring log formats without exception, the boring log forms were classified using the deep learning model ResNet 34 for a total of 6 boring log forms. As a result, the overall accuracy was 99.7, and the ROC_AUC score was 1.0, which separated the boring log forms with very high performance. After that, the text in the PDF is automatically read using the robotic processing automation technique fine-tuned for each form. Furthermore, the general information, strata information, and standard penetration test information were extracted, separated, and saved in the same format provided by the geotechnical information DB system. Finally, the information in the boring log was automatically converted into a DB at a speed of 140 pages per second.

• Journal of the Korean Geotechnical Society
• /
• v.34 no.7
• /
• pp.29-38
• /
• 2018

Three-dimensional continuum modeling of dynamic soil-pile-structure interaction embedded in a liquefiable sand was carried out. Finn model which can model liquefaction behavior using effective stress method was adopted to simulate development of pore water pressure according to shear deformation of soil directly in real time. Finn model was incorporated into Non-linear elastic, Mohr-Coulomb plastic model. Calibration of proposed modeling method was performed by comparing the results with those of the centrifuge tests performed by Wilson (1998). Excess pore pressure ratio, pile bending moment, pile head displacement-time history according to depth calculated by numerical analysis agreed reasonably well with the test results. Validation of the proposed modeling method was later performed using another test case, and good agreement between the computed and measured values was observed.

• Journal of the Korean Geotechnical Society
• /
• v.32 no.9
• /
• pp.51-62
• /
• 2016

Parametric studies for various site conditions by using 3d numerical model were carried out in order to estimate dynamic behavior of soil-pile-structure system in dry soil deposits. Proposed model was analyzed in time domain using FLAC3D which is commercial finite difference code to properly simulate nonlinear response of soil under strong earthquake. Mohr-Coulomb criterion was adopted as soil constitutive model. Soil nonlinearity was considered by adopting the hysteretic damping model, and an interface model which can simulate separation and slip between soil and pile was adopted. Simplified continuum modeling was used as boundary condition to reduce analysis time. Also, initial shear modulus and yield depth were appropriately determined for accurate simulation of system's nonlinear behavior. Parametric study was performed by varying weight of superstructure, pile length, pile head fixity, soil relative density with proposed numerical model. From the results of parametric study, it is identified that inertial force induced by superstructure is dominant on dynamic behavior of soil-pile-structure system and effect of kinematic force induced by soil movement was relatively small. Difference in dynamic behavior according to the pile length and pile head fixity was also numerically investigated.

• Journal of the Korean Geotechnical Society
• /
• v.16 no.4
• /
• pp.149-156
• /
• 2000

Sedimentation and self-weight consolidation tests in cylinder and large model tank and field measurement such as settlement and pore water pressure at each layer by wireless automatic instrumentation system were carried out to investigate the behaviour of dredged marine clay fill. The consolidation behaviour for each reclaimed layer was analyzed from these measured data and numerical analysis result using finite strain consolidation theory. It was fond from this study that the consolidation behaviour of dredged clay fill is heavily dependent on the filling process.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.5
• /
• pp.85-92
• /
• 2011

The dynamic behavior of piles becomes very complex due to soil-pile dynamic interaction, soil non-linearity, resonance phenomena of soil-pile system and so on. Therefore, the proper numerical simulation of the pile behavior needs much effort and calculation time. In this research, a new modeling method, which can be applied to the conventional finite difference analysis program FLAC 3D, was developed to reduce the calculation time. The soil domain in this method is divided into a near-field region and a far-field region, which is not influenced by the soil-pile dynamic interaction. Then, the ground motion of the far-field is applied to the boundaries of the near-field instead of modeling the far-field region as finite meshes. In addition, the soil non-linearity behavior is modeled by using the hysteretic damping model, which determines the soil tangent modulus as a function of shear strain and the interface element was applied to simulate the separation and slip between the soil and pile. The proposed method reduced the calculation time by as much as one third compared with a usual modeling method and maintained the accuracy of the calculated results. The calculated results by the proposed method showed a good agreement with the prototype pile behavior, which was obtained by applying a similitude law to the 1-g shaking table test results.