• Proceedings of the KSR Conference
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• 2005.11a
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• pp.418-423
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• 2005

In designing underground structure such as tunnels, estimating geotechnical characteristics of the ground is one of the most important and difficult tasks. In this paper, a methodology that can identify geotechnical parameters using only field-measured relative convergence displacements is presented. By using only relative convergence measurement data, inevitable errors in absolute convergence estimation can be avoided and in turn the parameter estimation process can be simplified. The methodology utilizes sensitivity relationship between static displacement measurements and geotechnical parameters. The feasibility and applicability of the proposed methodology is verified via a 3-d numerical example of a tunnel structure.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.83-94
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• 2000

Applicability of PMT in domestic area, test procedure, and methods determining the shear strength parameters $(cu,\phi)$and deformation character (E) using PMT results were studied. At six test boreholes of three construction sites in Pusan, PMT using Elastometer-200 type was performed. The problems occurring during tests were investigated and the test results were analysed.In-situ total horizontal stress could be obtained by observation from pressuremeter curve and limit pressure, ｐ could be determined by $ｐ-log(\Deltav/v)$ method. Shear strength parameters$(cu,\phi)$ and deformation modulus(G, E) could be determined from the PMT results. But effective friction angle and undrained cohesion determined from PMT results were greater than those obtained from laboratory test.Using PMT results, marine soil in Pusan could be classified approximately. Net limite pressure values were in the range of 6.4~22.5 $kg/cm^2$, in clay, 2.2~30.$kg/cm^2$, in sand, 13.0~58.0$kg/cm^2$, in weathered soil and 47.0~190.0 $kg/cm^2$, in weathered rock. Also, Em/ｐ values were in the range of 2.4~7.0 in clay, 2.6~12.1 in sand, 6.8~17.1 in weathered soil and 7.2~29.6 in weathered rock.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.49-57
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• 2022

In order to efficiently analysis the stability of a slope, measuring the shear strength of soil is needed. The Standard Penetration Test (SPT) is not appropriate for a slope inspection due to cost and weights. One of the ways to effectively measure the N-value is the Dynamic Cone Penetration Test (DCPT). This study was performed to develop a minimized multi-function sensors that can easily estimate CPT values and Volumetric Water Content. N value with multi-fuction sensor DCPT showed -2.5 ~ +3.9% error compared with the SPT N value (reference value) in the field tests. Also, the developed multi-fuction sensor system was tested the correlation between the CPT test and the portable tester with indoor test. The test result showed 0.85 R2 value in soil, 0.83 in weathered soil, and 0.98 in mixed soil. As a result of the field test, the multi-function sensor shows the excellent field applicability of the proposed sensor system. After further research, it is expected that the portable multi-function sensor will be useful for general slope inspection.

• The Journal of Engineering Geology
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• v.33 no.2
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• pp.293-305
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• 2023

Three ground models are analyzed using a 1g shaking table and laminar shear box (LSB) to investigate the impact of the ground structure on seismic wave amplification during earthquakes. Multi-layer horizontal, embankment, and basin ground models are selected for this investigation, with each model being divided into dense and loose ground layers, Accelerometers are installed during the construction of each ground model to capture any seismic wave amplification owing th the propagation of an artificial seismic wave, sine wave sweep, and 10-Hz sine wave through a given ground model. The amplification of the tested seismic waves is analyzed using the observed peak ground acceleration and spectrum acceleration. The observed acceleration amplification in the multi-layer horizontal ground model is significantly higher the seismic waves that propagated across the dense ground-loose ground boundary compared with those that only propagated through the dense ground. Furthermore, the observed acceleration amplification gradually increases in the central part of the multi-layer embankment and basin models for the seismic waves that propagated across the dense ground-loose ground boundary.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.95-102
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• 2003

Corestone rock mass has complex characters because it is made up of stronger and stiffer corestone in a weaker and softer matrix. Physical model corestone rock mass made up of stiffer corestone in weaker matrix were tested in uniaxial compression and numercal modelling analysis The result of the uniaxial compression tests showed that increasing the corestone proportion generally increased the modulus of deformation. And the strength decreased in the lower corestone proportion, but it increased in the higher proportion(45%, 65% corestone by volume). The strength and the modulus of deformation were not affected by different size coretone on the same proportion. The result of the numerical modelling analysis showed similar trend compared with the result of the result of the uniaxial compression test. But though the result of th uniaxial compression test is similar to the result of the numerical modelling analysis, it's unreasonalble to apply the results of this paper to in situ corestone rock mass. So mere laboratory tests including triaxial test and the other numerical program analyses are necessary to apply the results to in situ corestone mass

• Geotechnical Engineering
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• v.7 no.4
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• pp.65-74
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• 1991

Earth structures which located on the weak foundation settle for the long time due to the their own weight (embankment) simultaneously. Because of the consolidation and creep which are timedependent behaviour. This paper is presented creep test Processes using triaxial spparatus, and investigated creep charateristics of marine clay by creep test according to stress level And required and appropriate creep parameters of soil used in the creep equation are investigated by the creep test.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.792-802
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• 2008

If a tunnel is constructed below the groundwater level, the groundwater flow will occur inducing the seepage force toward the tunnel and will result in the increase of tunnel convergence. The longitudinal deformation during tunnel excavation will also be increased due to seepage pressure. A back-analysis methodology in underwater tunnel was proposed in this study based on the relative longitudinal deformation measured in-situ. Geotechnical parameters can be estimated utilizing the proposed method where the prior estimate as well as the measured convergence can be reasonably combined by adopting the Extend Bayesian Method.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.175-182
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• 2001

The PMT test results are compared with other in situ test such as Standard Penetration Test (SPT), Cone Penetration Test (CPT), Field Vane Test (FVT) and the laboratory test in order to investigate the correlationships for the strength parameters obtained from Busan and Incheon areas. Many proposed correlation formulas also make a comparative study and new correlation formulas for domestic soils are introduced. Limit pressure ( $P_1$) could be determined by P-log($\Delta$V/V) and Relative volume Method. PMT for the granular soils showed relatively high correlation with SPT, while CPT has good correlation with PMT for cohesive soil. The predicted undrained shear test ( $S_{u}$) by the PMT test results for Incheon and Busan samples showed low correlativity with proposed equations, therefore, new correlation formulas are proposed for domestic soils.s.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.952-960
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• 2009

Foundation soils are greatly influenced on the stability of structures. The soft clay deposited in Incheon Port area is named either nomally consolidated clay or unconsolidated clay. New harbor structures will be constructed in Incheon Port area. Not sufficient soil boring datum are obtained from the filed soil exploration due to limited time and cost. The harbor construct site is pretty large area and the soils are not homogenous. This paper presented the result of reliability analysis which was performed by both Bayesian approach and analysis of variance.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1399-1406
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• 2009

Probability distribution of geotechnical properties is very useful information and it is used for evaluating the geotechnical properties itself and calculating probability of failure. In this study, probability distribution of compression index, recompression index, and void ratio are evaluated, and analysis results show that all property distributions satisfy normal and log-normal distribution.