• Geomechanics and Engineering
• /
• v.39 no.1
• /
• pp.87-104
• /
• 2024

In practical engineering, the design process for most retaining walls necessitates careful consideration of seismic resistance. The prevention of retaining wall overturning is of paramount importance, especially in cases where the foundation's bearing capacity is limited. To research the seismic active earth pressure (ES) of a relieving retaining wall rotating around base (RB), the shear dissipation graphs across various operating conditions are analyzed by using Optum software, and the earth pressure in each region was derived by the inclined strip method combined with the limit equilibrium method. By observing shear dissipation graphs across various operating conditions, the distribution law of each sliding surface is summarized, and three typical failure modes are obtained. The corresponding calculation model was established. Then the resultant force and its action point were obtained. By comparing the theoretical and numerical solutions with the previous studies, the correctness of the derived formula is proved. The variation of earth pressure distribution and resultant force under seismic acceleration are studied. The unloading plate's position, the wall heel's length, and seismic acceleration will weaken the unloading effect. On the contrary, the length of the unloading plate and the friction angle of the filling will strengthen the unloading effect. The derived formula proposed in this study demonstrates a remarkable level of accuracy under both static and seismic loading conditions. Additionally, it serves as a valuable design reference for the prevention of overturning in relieving retaining walls.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.11c
• /
• pp.85-94
• /
• 1999

Reinforced Soil Wall has several merits comparing with conventional retaining wall. The conventional method has the limit of wall height, ununiform settlement of the foundation ground, quality assurance of the embankment body, shortening of construction period, economical construction and so on. Basis of previous mentioned things reinforced soil wall is the substitutional method of conventional retaining wall and its necessity is continuously increasing. The embanking material used in reinforced soil wall is generally limited such as a good quality sandy soil, and in many case constructors have to transfer such a good embanking material from far away to construction site. As a result, they would pressed by time and economy. If poor soils could be used embanking material, for example, clayey soil produced in-situ by cutting and excavation, the economical merit of reinforced soil wall would be increased more and more. Likewise, a lot of study about laboratory experimental behavior of reinforced soil wall using a good quality soil is being performed, but is rare study about clayey soil containing much volume of fine particle relatively in korea. In this study, the authors investigated behavior of the geosynthetic reinforced and unreinforced soil walls using clayey soil as embanking material in view of horizontal movement of walls, bearing capacity and reinforcement stress.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.02a
• /
• pp.1-11
• /
• 2000

The use of Compaction Grouting evolved in 1950's to correct structural settlement of buildings. Over the almost 50 years, the technology has been developed and is currently used in wide range of applications. Compaction Grouting, the injection of a very stiff, 'zero-slump' mortar grout under relatively high pressure, displaces and compacts soils. It can effectively repair natural or man-made soil strength deficiencies in variety of soil formations. Major applications of Compaction Grouting include densifying loose soils or fill voids caused by sinkholes, poorly compacted fills, broken utilities, improper dewatering, or soft ground tunneling excavation. Other applications include preventing liquefation, re-leveling settled structures, and using compaction grout bulbs as structural elements of minipiles or underpinning. In this paper, on the basis of the case history constructed in this year, a study has been performed to analyze the basic mechanism of the Compaction Grouting. Also, the effectiveness of the ground improvement and the bearing capacity of the Compaction Pile has been verified by the Cone Penetration Test(CPT) and Load Test. Relatively uniform Compaction grouting column could be maintained by planning the Quality Control in the course of grouting. And, the Quality Control Plan has been conceived using grout pressure, volume of grout and drilling depth.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.539-545
• /
• 2010

The field plate test has a good potential for determining since it measures both plate pressure and settlement. The deformation modulus of rock mass is differently measured for status of structures. The values of deformation modulus are obtained from laboratory test (uniaxial and triaxial test) and field test (pressuremeter test). Plate load test should be conducted by different loading plate sizes for geological structure of rock mass and scale of structures. In this paper, large plate load tests were performed to predict of structure's behavior and evaluate the ultimate bearing capacity of the foundation on soft rock. Simultaneously, deformation modulus of rock mass was estimated by back analysis of stresses measured in field test under rock mass. Finally, we verified the validation of deformation modulus of rock mass through result of large plate load test and numerical simulation.

• Geomechanics and Engineering
• /
• v.17 no.5
• /
• pp.439-444
• /
• 2019

It is generally known that high strength soil is indicative of well-graded particle size distribution. However, there are some special cases of firm ground despite poor grade distribution, especially a specific gap-graded soil. Based on these discoveries, this study investigated the development of an additive of gap-graded soils designed to increase soil strength. This theoretical concept was used to calculate the mixed ratio required for optimal soil strength of the ground sample. The gap-graded aggregate was added according to Plato's polyhedral theory and subsequently calculated ratio and soil strength characteristics were then compared to characteristics of the original soil sample through various test results. In addition, the underground stress transfer rate was measured according to the test conditions. The test results showed that the ground settlement and stress limit thickness were reduced with the incorporation of gap-graded soil. Further field tests would confirm the reproducibility and reliability of the technology by using gap-graded soil to reinforce soft ground of a new construction site. Gap-graded soil has the potential to reduce the construction cost and time of construction compared to other reinforcing methods.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.1042-1050
• /
• 2008

In this study, SCP method was used by purpose to improve loose sand and soft clay that is drilled Sand Compaction Pile in underground. Settlement behavior of field analyzed through SCP method. When sand Compaction Pile drilled in clay, forming composite ground that foundation and Sand Compaction Pile behavior. According to SCP method can expect bearing capacity improvement, Settlement reduction, lateral flow protection. SCP increase the consolidation settlement of ground and it reduce settlement for that purpose increase liquefaction resistance, lateral Resistance. Because SCP had been widely used for sand. Area of Inchon-A by sand compose clay and silt to upper Ground and compose soft clay to under ground. After pre-loading, it measured settlement by extensometer and settlement extensometer that purpose of ground improvement with 13% in replacement ratio. The result analyzed settlement behavior is similar to Multi-layered Ground that it happened to elastic settlement at upper ground and to consolidation settlement at under ground.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.245-248
• /
• 2001

During the core drilling for the design of a railway bridge crossing over the inferred fault system along the river, fracture zone, extends vertically more than the bottom of borehole, filled with fault gouge was found. The safety of bridge could be threatened by the excessive subsidence or the reduced bearing capacity of bedrock, if a fault would be developed under or around the pier foundation. Thus, a close examination of the fault was required to rearrange pier locations away from the fault or to select a reinforcement method if necessary. Geophysical methods, seismic reflection method and electrical resistivity survey over the water covered area, were applied to delineate the weak zone associated with the fault system. The results of geophysical survey clearly showed a number of faults extending vertically more than 50m. Reinforcement was not desirable because of the high cost and the water contamination, etc. The pier locations were thus rearranged based on the results of geophysical surveys to avoid the undesirable situations, and additional core drillings on the rearranged pier locations were carried out. The bedrock conditions at the additional drilling sites turned out to be acceptable for the construction of piers.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.6
• /
• pp.41-49
• /
• 2009

Poor compaction of subgrade soil causes low stiffness and bearing capacity of sublayers so that faulting and differential settlements can be generated between new and old pavement surfaces in case of widening works. However, investigation of verifying the reason of producing the defects in the pavements are not performed in detail. In this study, several in-field tests including PMT and PBT were performed for obtaining stiffness of the sublayers in new and old pavements respectively of an widening project. Then, based on the obtained stiffness values and the measured deformations obtained by specially designed tilt meters, the main reasons of generating different deformations between the old and new pavement sections and the relationship between the deformation and stiffness are verified.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.4
• /
• pp.71-76
• /
• 2012

Shear strength of soil is power that resists failure and sliding according to any face in soils and one of the most important factors during engineering properties of soil. Shear strength is used for engineering science problems as bearing capacity methods of foundation or piles, slope stability after dam or Cutting Embankment and stability problem analysis of soils as lateral earth pressure of soil structures, ets. This study has analyzed shear strength change of samples classified 2.00mm(10sieve)와 0.85mm(20sieve), 0.475mm(40sieve) using direct shear tester after removing and drying cohesive soil ingredient of Weathered granite soil Therefore, this study would help studies about shear strength properties by particle size.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.33 no.6
• /
• pp.374-382
• /
• 2021

The scour risk assessment was conducted for ultimate limit state of newly developed penta pod suction bucket support structures for a 5.5 MW offshore wind turbine. The hazard was found by using an empirical formula for scour depth suitable for considering marine environmental conditions such as significant wave height, significant wave period, and current velocity. The scour fragility curve was calculated by using allowable bearing capacity criteria of suction foundation. The scour risk was assessed by combining the scour hazard and the scour fragility.