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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geotechnical Society
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Journal DOI :
Korean Geotechical Society
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Volume & Issues
Volume 23, Issue 12 - Dec 2007
Volume 23, Issue 11 - Nov 2007
Volume 23, Issue 10 - Oct 2007
Volume 23, Issue 9 - Sep 2007
Volume 23, Issue 8 - Aug 2007
Volume 23, Issue 7 - Jul 2007
Volume 23, Issue 6 - Jun 2007
Volume 23, Issue 5 - May 2007
Volume 23, Issue 4 - Apr 2007
Volume 23, Issue 3 - Mar 2007
Volume 23, Issue 2 - Feb 2007
Volume 23, Issue 1 - Jan 2007
Selecting the target year
Evaluation of Normalized Behaviors of Bridge Foundations Reinforced by Micropiles
Park, Seong-Wan ; Jung, Dong-Jin ; Kwak, Ki-Seok ; Lee, Ju-Hyung ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 5~14
The purpose of this study is to evaluate the normalized behaviors of existing bridge foundations reinforced by micropiles. In order to do numerical method a finite element program was used to predict the micropile behavior and quantify their reinforcing effects on existing bridge foundations. In addition, the installation effects of battered micropiles on existing foundations were compared with vertically reinforced bridge foundations. Based on the study performed, it was found that the use of battered micropiles more efficiently reduces displacement of existing foundations than vertically installed micropiles under vertical and horizontal loadings, respectively. The batter angle of micropiles was also found to be most effective at about
in reducing the vertical displacement. The horizontal reinforcing effect continues to be larger with an increase in batter angles. So, it is believed that the results presented could give an idea to enhance In-service performance of existing bridge foundations reinforced by micropiles.
Load Carrying Capacity of Geosynthetic-Reinforced Stone Column in Cohesionless Ground
Yoo, Chung-Sik ; Song, Ah-Ran ; Kim, Sun-Bin ; Lee, Dae-Young ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 15~27
This paper deals with the bearing capacity behaviour of geosynthetic-reinforced stone column(GRSC) constructed in soft ground, as part of an investigation regarding the applicability of GRSC in Korea. In this study, two-dimensional finite element analyses were performed to investigate the effect of relevant design factors on the bearing capacity behaviour. The parametric study is performed for various influencing factors. The results indicated that the geogrid encasement tends to significantly improve the load carrying capacity of a stone column. Also found were that the geogrid encasement length and its stiffness significantly affect the load carrying capacity behaviour of GRSC, and that the encasement length of three times the stone column diameter is sufficient in mobilizing the full reinforcement effect. Practical implications of the findings are discussed.
A Study on the Safety Assessment Technique of a Tunnel Using Critical Stain Concept
Park, Si-Hyun ; Shin, Yong-Seok ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 29~41
An assesment technique for the quantitative evaluation of tunnel safety during tunnel excavation was newly proposed in this study using displacement measurements. First of all, field measurement guidelines used at tunnel construction sites in Korea and other countries were investigated. It was found out that the criteria of the guidelines were not clear and varied depending on the construction sites. The practical use of field measurement data for the evaluation of tunnel safety was very limited due to uncertainties of the guidelines related to the interpretation of measured data during the excavation. Critical strain concept is introduced in this study for the assesment of tunnel safety during the tunnel excavation. Moreover, the characteristics of tunnel displacements caused by the tunnel excavation were investigated in detail in order to investigate the practical application of the critical strain concept. The total tunnel displacements can be subdivided into three parts: displacements occurring ahead of tunnel face, displacements occurring prior to measurements, and displacements occurring after the installation of instruments. The characteristic of each portion of displacements is analysed in this study. Finally, a general method on the use of the displacement measurement data for the critical strain concept was suggested in the concrete manner, considering the field measurement practice in Korea.
Frost Heave Force of Ground and Countermeasure for Damage of Structures
Rui, Da-Hu ; Teruyuki, Suzuki ; Kim, Young-Su ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 43~51
Frost action may cause extensive damage to building, structures, roads, railways and utility lines in seasonal frost. The research about frost heave of natural ground has been considerably performed. In late years various structures have become complicated with the development of social infrastructure maintenance. Therefore countermeasure to frost heave becomes a matter of great importance from a new viewpoint. This study was aimed at catching natural ground frost heaving force quantitatively. Frost heaving forces on circular steel plates which were set on ground surface were measured in field test. The frost heaving forces arise at freezing front propagates to the structures through frozen soil layer. Besides, a full scale model of multi-anchored retaining wall was installed in field, and the freezing lines, frost heave pressure to act on a wall block, and so on were measured. Finally, the position and shape of frost line were estimated by using numerical simulation and a method to determine replacement range was suggested with soil properties and weather data.
Development of Automatic Displacement Measuring System Using 3D Digital Photogrammetry Image and Its Application
Han, Jung-Geun ; Kim, Young-Seok ; Cho, Sam-Duk ; Kwak, Ki-Seok ; Hong, Ki-Kwon ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 53~62
Recently, for the stabilization estimation of structures, many automatic measuring instruments with expensiveness and high accuracy have been developed and utilized. However, the existing manual measuring systems are almost impossible to measure the real-time for the whole surface of large-scale structures and an automatic measuring system has disadvantages with demanding enormous expense. In this study, 3D digital visual monitoring system was developed by using digital photogrammetry technique. To confirm application of developed system, it was applied to the measurement of the wall displacement of concrete surface and displacement measurement of reinforced-soil wall block. Then, the result of the test was compared with measuring value of total station. Based on the results of the comparison, the application of visual monitoring system was evaluated. The results show that the developed visual monitoring system could be available in displacement measure of structures.
Three Dimensional Numerical Analysis of Piled Raft on Soft Clay
Lee, Jin-Hyung ; Jeong, Sang-Seom ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 63~75
Piled raft is known to be an unfavorable foundation type in soft clay because foundation is associated with both excessive settlement and bearing capacity failure problems. Despite these reasons, in recent decades, an increasing number of structures have been constructed over soft clay area, piled raft concepts arouse interest as the foundation of structures on soft clay area becomes popular. This study described 3 dimensional behavior of piled raft on soft clay based on a numerical study using 3D finite element method. A series of numerical analyses were performed for a various pile lengths and the pile configurations on the raft were subjected to vertical uniform or point loading. Based on the results of the parametric study, comparisons were made among the effect of loading type, various pile length and configurations, and the load-settlement behavior and load sharing characteristics of piled raft were also evaluated. From the results, the characteristic of piled raft on soft clay was examined.
Lateral Earth Pressures Acting on Anchored Diaphragm Walls and Deformation Behavior of Walls during Excavation
Hong, Won-Pyo ; Lee, Moon-Ku ; Lee, Jae-Ho ; Yun, Jung-Mann ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 77~88
Lateral earth pressure and horizontal displacement of the diaphragm walls constructed in multi-soil layers were analyzed by the field instrumentation from six building construction sites in urban area. The distribution of the developed earth pressure of the anchored diaphragm walls during excavation shows approximately a trapezoid diagram. The maximum earth pressure of anchored diaphragm walls corresponds to
and the earth pressure acts at the upper part of the walls. The maximum earth pressure is two times larger than the empirical earth pressure of flexible walls in sands suggested by Terzaghi and Peck(1967), Tschebotarioff(1973), and Hong and Yun(1995a). The horizontal displacement of diaphragm walls is closely related with supporting systems such as struts, anchors, and so on. The horizontal displacement of anchored walls shows less than 0.1 percent of the excavated depth, and the horizontal displacement of strutted walls shows less than 0.25 percent of the excavated depth. Therefore, the restraining effect of horizontal displacement to the anchored diaphragm walls is larger than the strutted diaphragm walls. In addition, since the horizontal displacement of the diaphragm walls is lower than the criterion,
, used for control the anchored retention wall using soilder piles, the safety of excavation sites applied with the diaphragm walls is pretty excellent.
Bearing Capacity Evaluation of Marine Clay Dredged Deposit Including Desiccated Crust Layer
Park, Hyun-Ku ; Byeon, Wi-Yong ; Jee, Sung-Hyun ; Lee, Seung-Rae ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 89~100
In this study, various field and laboratory tests were performed to investigate the characteristics of shear strength and bearing behavior to be considered in the estimation of stability and trafficability in early stage of stabilization process in marine clay dredged deposit. Site characterization was carried out to grasp the basic properties of the deposit. Field vane test, unconfined compression test and direct shear test were conducted to evaluate the shear strength distribution for varied depths, and the characteristics of shear strength and stress-strain behavior of the crust layer. Plate load tests were also performed to estimate the bearing capacity and to assess load-settlement behavior and failure pattern of the deposit. The bearing capacity was also estimated using previously proposed methods for double-layered clay deposit. The estimated bearing capacity was compared with the results of the plate load tests and then, the applicability of the estimation method was discussed.
Estimation of Bearing Capacity of Non-Displacement Piles in Sand Considering Pile Shape
Paik, Kyu-Ho ; Lee, Jun-Hwan ; Kim, Dae-Hong ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 101~110
In order to investigate the effect of the pile shape on the bearing capacity of non-displacement piles, a series of model pile load tests were performed using a calibration chamber and three model piles with different shape. Results of the model tests showed that the bearing capacity of tapered piles was affected by its taper angle as well as the stress states and relative density of soil. Based on the results of model pile load tests, a new design equation for estimation of the bearing capacity of non-displacement piles was proposed, and it takes into account the effect of the taper angles on the bearing capacity of non-displacement piles.
Estimation of End Bearing Capacity of SDA Augered Piles on Various Hearing Stratums
Hong, Won-Pyo ; Chai, Soo-Geun ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 111~129
The standard construction manual of the SDA(Separated Doughnut Auger) piling method was proposed so that the resisting capacity of the augered piles could work effectively. 405 dynamic pile load tests and 30 static pile load tests were performed for 265 test piles, which were installed by the SDA piling method in 33 sites in Korea. The results of the pile load tests showed that the end bearing capacity of the SDA augered piles depended on the property of various soil stratums and did not agree with ones estimated by the existing formula based on several standard design codes. On the basis of the pile load test results, four formulas were presented according to bearing stratums to estimate quantitatively the unit end bearing capacity of the SDA augered piles. The formulas for the unit end bearing capacity of piles on soils or weathered rocks were related to N-value given by SPT(Standard Penetration Test), while the unit end bearing capacity on bedrock was suggested to be more than 1500
. The presented formulas were compared with the existing formulas, which were presented by several standard design codes to design the augered piles. In order to use correctly the presented formulas, the quality of Standard Penetration Test should be controlled precisely. Also it is desirable to choose a pilot construction site, where both dynamic and static pile load tests are performed.
Pile and Ground Responses during Driving of a Long PHC Pile in Deep Soft Clay
Kim, Sung-Ryul ; Dung, N.T. ; Chung, Sung-Gyo ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 131~141
Because pile behavior is governed by geotechnical characteristics of surrounding soils, it is therefore necessary to monitor ground responses during pile driving and analyze the relation between the behaviors of pile and ground. In this research, the 57 m long PHC pile was driven into deep soft clay in the Nakdong River estuary area. During and after the pile driving, the ground responses and the residual load of pile have been monitored for about a year, by using piezometers, inclinometers, level posts for surface settlement, and strain gauges in piles etc. As the results, the residual load by the negative skin friction along the pile increased with the dissipation of the excess pore pressure, which was developed by pile driving and reclamation. About 30% of the maximum residual load developed due to the dissipation of the increased excess pore pressure during the driving. It is thus emphasized that most piles driven in clay deposits need to be designed by considering negative skin friction along the pile.
Effect of Stress Level on Strength Parameters of Cemented Sand
Lee, Moon-Joo ; Choi, Sung-Kun ; Choo, Hyun-Wook ; Cho, Yong-Soon ; Lee, Woo-Jin ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 143~151
The factors affecting the geotechnical properties of cemented sands are known to be relative density, cementation level, stress level, and particle characteristics such as particle size, shape and surface conditions. It has been widely accepted that the friction angle of cemented sands is not affected by cementation while the cohesion of cemented sands was significantly influenced by cementation. The cementation that is a critical component of the strength of cemented sands will be broken with increasing confining pressure and great caution is required in evaluating the cohesion of cemented specimens due to their fragilities. In this study, a series of drained shear tests were performed with specimens at various cementation levels and confining stresses to evaluate the strength parameters of cemented sands. From the experiments, it was concluded that the cohesion intercept of cemented sand experiences three distinctive zone(cementation control zone, transition zone, and stress control zone), as the cementation level and the confining stress varies. In addition, for accurate evaluation of the strength parameters, the level of confining stress triggering the breakage of cementation bond should be determined. In this study, the relationship between the maximum confining stresses capable of maintaining the cementation bond intact and unconfined compression strength of the cemented sand was established.
Investigation of Proper Replacement Depth for the Reinforced Earth Wall on a Soft Ground by Finite Element Analysis
Lee, Byung-Sik ;
Journal of the Korean Geotechnical Society, volume 23, issue 5, 2007, Pages 153~162
For the reinforced earth wall constructed on a soft ground in parallel with replacing soft soils, the behavior of the wall according to variations of thickness and stiffness of soft layer, replacement depth, and wall height is investigated using a finite element method, in which incremental construction steps including consolidation of soft soil layer are considered. The behavior of wall is characterized by investigating displacements and settlements developing at the wall, and shear strains developing in a soil deposit. The stability of wall is, then, evaluated by comparing these values with the safety criteria determined on the basis of the literature. Based on the investigation, it is shown that the behavior of wall is influenced naturally from soft soil thickness(t), replacement depth(d) and wall height(h), but more significantly from d and h. In addition, it is also shown that the normalized replacement depth, d/h, required for the safety of wall is not influenced significantly by the variations of t and h. Consequently, it can be concluded that the proper replacement depth can be suggested in an equivalent value in terms of d/h, even for the cases where the wall height is varying with stations, but the variation is not significant.