Yonsei University · Engineering
Professor Junhwan Lee's research lab specializes in geotechnical engineering with a focus on the behavior of shallow and deep foundations in granular soils, particularly under working load conditions. The lab investigates the influence of groundwater level fluctuations, soil nonlinearity, and in-situ test data (such as CPT and SPT) on settlement and bearing capacity predictions. Key research directions include the development of advanced numerical and experimental methods to reduce uncertainties in geotechnical design, with emphasis on pile-soil interaction, piled raft systems, and the mechanical response of soils with varying fines content. The lab combines centrifuge modeling, full-scale field tests, and advanced constitutive modeling to improve the accuracy and reliability of geotechnical design methods.
Figures are computed from collected data and may differ slightly.
The sustainable performance of foundations of various urban buildings and infrastructures is strongly affected by groundwater level (GWL), as GWL causes changes in the stress state within soil. In the present study, the components affecting GWL were investigated, focusing on the effects of precipitation and river stage. These components were analyzed using a six-year database established for hydrological and groundwater monitoring data. Five study regions for which daily measured precipitation,
In the present paper, the estimation of limit unit bearing capacity qbL of axially loaded circular footings on sands based on cone penetration test cone resistance qc is examined. There are significant uncertainties in the calculation of bearing capacity using the bearing capacity equation. The selection of the value of the soil friction angle ϕ and of the equation for Nγ accounts for much of the overall uncertainty. The approach proposed in this study can reduce the uncertainties associated wit
Pipe piles can be classified as either closed- or open-ended piles. In the present paper, the load capacity of both closed- and open-ended piles is related to cone penetration resistance qc through an experimental program using calibration chamber model pile load tests and field pile load tests. A total of 36 calibration chamber pile load tests and two full-scale field pile load tests were analyzed. All the test piles were instrumented for separate measurement of each component of pile load capa
In the current study, the load responses and interaction effects of piled rafts embedded in sands were investigated. A series of centrifuge load tests were conducted using different types of model foundations. Single piles, group piles, piled rafts, and unpiled rafts were adopted in the tests to analyze various interaction effects of piled rafts. The load-settlement curves of piled rafts were similar to those of group piles for the initial settlement range and became similar to those of rafts as
The settlement of foundations under working load conditions is an important design consideration. Well‐designed foundations induce stress‐strain states in the soil that are neither in the linear elastic range nor in the range usually associated with perfect plasticity. Thus, in order to accurately predict working settlements, analyses that are more realistic than simple elastic analyses are required. The settlements of footings in sand are often estimated based on the results of in situ tests, p
Soils behave nonlinearly from very early loading stages. When granular soils contain a certain amount of fines, the degree of nonlinearity also changes, as stiffness and strength characteristics vary with fines content. Hyperbolic stressstrain models and variations of these models are often used for description of the nonlinear behavior. A modified hyperbolic stressstrain relationship is used in this paper for representing the degradation of the elastic modulus of silty sands. The model is bas
The estimation of base resistance is a key step in the design of piles embedded in moderately dense to dense sand. Calibration chamber plate load tests are sometimes used to investigate the base load - settlement relationship of nondisplacement piles in sand. In such tests, the sand specimens are carefully prepared to simulate the installation of nondisplacement piles. In this paper, calibration chamber tests are analyzed using the finite element method; experimental and numerical results are co
Most of the existing methods for estimating settlements of footings in sand have been developed for either isolated square footings or for strip footings. The literature contains limited information on settlement analysis of rectangular footings, and, as a result, there is no way to accurately account for the effect of the footing length-to-width ratio on settlement. Additionally, no practical method exists for considering the interaction between neighboring footings in settlement estimates. In
In this study, the lateral load–carrying capacity of micropiles was investigated focusing on the effect of micropile inclination. A series of model load tests was conducted for both single (SMP) and group (GMP) micropiles with various configuration conditions of inclination angle, load direction, and micropile spacing. To clarify the load-carrying mechanism of inclined micropiles, a finite-element (FE) analysis was performed. The lateral load–carrying capacity of inclined SMPs increased with θ u
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