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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Geotechnical Society
Journal Basic Information
Journal DOI :
Korean Geotechical Society
Editor in Chief :
Seong Wan Park
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
A Study on the Evaluation of the Loads Acting on the Pillar in Two-Arch Tunnel
Oh, Gyoo-Chul ; Chun, Byung-Sik ; Do, Jong-Nam ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 5~14
In this study, Matsuda formula used to evaluate the loads acting on the pillar was investigated and load reduction factor(
) was evaluated by numerical analysis to better apply for the design. From the results, normal stress was concentrated to one side due to excavation of preceding tunnel after construction of pillar. And 86.5% of maximum normal stress was revealed partly unequally when the ground was poor. By numerical analysis,
of total loads calculated by Matsuda formula decreased and then, from these results, load reduction factor(
) was estimated. From now on, stability and economic aspects could be guaranteed by applying the load reduction factor(
Los Angeles Abrasion Test for Estimating Engineering Index on the Sedimentary Rocks of Kyeongsang Basin
Min, Tuk-Ki ; Moon, Jong-Kyu ; Lee, Sang-Il ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 15~26
Los Angeles abrasion loss test has usally been applied to the quarry for the purpose of aggregate hardness estimation. 324 blocks from 25 sites of Kyeongsang basin samples of sedimentary rock were examined and tested in laboratary. This paper found that L. A. abrasion loss test is a good method to estimate engineering index such as uniaxial compressive strength, elastic modulus, indirect tensile strength, point load strength index, Schmidt hammer rebound value of sedimentary rocks with high correlation factor. Engineers will prefer L. A. abrasion loss test to the other one for design and construction as this method is quick and easy.
Development of Automatic Shear-wave Source for Downhole Seismic Method
Bang, Eun-Seok ; Sung, Nak-Hoon ; Kim, Jung-Ho ; Kim, Dong-Soo ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 27~37
Downhole seismic method is very economic and easy to operate because it uses only one borehole and simple surface source to obtain the shear wave velocity profile of a site. In this study, automatic shear wave source was developed for efficient downhole seismic testing. This source is motor-spring type and easy to control. It can lessen the labor of operator and the working time. Moreover, it can provide better and repetitive signals for data interpretation. By combining developed automatic source with automatic receiver system, PC based data acquisition system, advanced managing program, and semi-automatic downhole performing system were constructed. Through comparison test with manual source, advantages of automatic source were verified. Constructed semi-automatic downhole testing system including automatic shear wave source was applied to the soft soil site. The applicability and reliability were verified and the importance of automating testing system for obtaining reliable result was emphasized.
Dynamic Deformation Characteristics of Sands Under Various Drainage Conditions
Lim, Seong-Yoon ; Song, Chang-Seob ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 39~48
The soil-water characteristic curve(SWCC) is a useful tool in the prediction of the engineering behavior of unsaturated soils. Several equations are available in the literature to mathematically represent the experimental behavior of the SWCC. Some equations are based on the assumption that the shape of curve is dependent upon pore-size distribution. Other equations assume that SWCC can be estimated from the grain size distribution and the physical properties of soils. This study evaluated the suitability of using two different SWCC equations for defining the relationship between water content and matric suction. Various parameters that influence the SWCC behavior are also briefly discussed.
Analysis of Fine Particle Transfer and Shear Strength Increase Using PFC in Permeation Grouting
Lee, Wan-Ho ; Lim, Heui-Dae ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 49~58
Numerical experiments using a distinct element code (PFC3D) were carried out for the analysis of grout-material transfer in soil layers and also for the analysis of increase in mechanical strength after permeation grouting. For rapid analysis, up-scaling analysis in length scale was adopted, and the following observations were made from the numerical experiments. Firstly, the relative size of grout material with respect to the in situ soil particles controlled the transfer distance of the grout particles. When the size of grout particle was 0.2 to 0.25 times of the in situ soil particles, clogging of pore spaces among the in situ soil particles occurred, resulting in restricted propagation of grout particles. It was also found that there was a threshold value in the size of grout particle. Below the threshold value, the transfer distance of the grout particle did not increase with the decrease of particle size of the grout material. Secondly, the increase in cohesion and internal friction angle was observed in the numerical specimen with grouting treatment, but not with the untreated specimen.
An Experimental Study on Compaction Characteristics of Gravel-mixed Decomposed Granite Soil
Ham, Tae-Gew ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 59~66
In order to clarify the influence of gravel content on the mechanical properties of gravel-mixed decompose granite soils, large-scale one-dimensional compression tests were performed. The sample used in the study was a decomposed granite soil from Shimonoseki in Yamaguchi prefecture in Japan. After adjusting the grain size of the said soils, the specimen compacted with a certain level of compaction energy was put to the test. Based on the results obtained, when gravel-mixed decomposed granite soil was compacted at the same energy level, there existed the specific gravel content at which dry density was maximum and which also produced the minimum compression index. Furthermore, from these results, an expression based on a two-phase mixture theory was proposed to quantitatively evaluate the effects of gravel content and initial dry density and the material parameters calculated through the proposed method proved to exactly estimate the actual measuring value.
Estimation of Weight Distribution of Rockfall Block by Joint Measurement And Study on Its Application to Rockfall Simulation
Kim, Dong-Hee ; Ryu, Dong-Woo ; Kim, Su-Chul ; Yoon, Sang-Kil ; Lee, Woo-Jin ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 67~76
The characteristics of rockfall are determined by virtually all factors and conditions e.g. the physical figure of the slope such as inclination, height, roughness, the elemental figure of the slope such as vegetation and material deposited, and the shape and weight of the rockfall itself. Although it is one of the major factors to be considered in rockfall simulation, little attention has been given to the weight of the rockfall. And, since the size of the rockfall is dominated by joint spacing, the distribution of the rockfall block weight can be predicted as a function of the joint spacing. In this study, the weight distribution of rockfall was estimated by using the method of volumetric joint count,
, based on joint spacing, and
. The results indicate that the weight distributions were analogous in two methods, and the distribution was to be
for 200 kilograms or lesser,
for 400 kilograms or more, which show good matches with the actual on-site weight distribution. Therefore, the weight distribution of rockfall suggested in this paper is able to be considered as appropriate data for rockfall simulation.
Development of Composite Geo-Material for Recycling Dredged Soil and Bottom Ash
Kim, Yun-Tae ; Han, Woo-Jong ; Jung, Du-Hwoe ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 77~85
This paper investigates the mechanical characteristics of composite geo-material which was developed to reuse both dredged soils and bottom ash. The composite geo-material used in this experiment consists of dredged soil taken from the construction site of Busan New Port, cement, air foam and bottom ash. Bottom ash is a by-product generated at the Samcheonpo thermal power plant. Several series of laboratory tests were performed to investigate behavior characteristics of composite gee-material, in particular the reinforcing effect by mixing bottom ash. The experimental results of composite geo-material indicated that the stress-strain relationship and the unconfined compressive strength are strongly influenced by mixing conditions. Especially it was observed that the compressive strength of composite geo-material increased with an increase in bottom ash content due to reinforcing effect by the bottom ash. Compressive strength of composite geo-material increased with the increase in curing time. The 28-day strength of composite geo-material is
times higher than the 7-day strength. The moist unit weight strongly depended on air-foam content as well as bottom ash content added to the composite goo-material. In composite geo-material, secant modulus (
) also increased as its compressive strength increased due to the inclusion of bottom ash.
Estimation of the Mechanical Properties of the Concrete Tunnel Lining by Drilling Resistance Test
Choi, Soon-Wook ; Sung, Yun-Chang ; Cheong, Ho-Seop ; Chang, Soo-Ho ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 87~98
For the quick rehabilitation of a fire-damaged tunnel structure, it is the most important procedure to investigate the fire-induced damaged zone rapidly. This study aims to propose a new drilling resistance testing method by which mechanical properties of tunnel concrete lining altered by high temperature can be estimated easily and continuously. Especially, it alms to derive the relationships to estimate mechanical properties of mortar and concrete materials from drilling parameters. To obtain the optimum testing condition, a series of drilling resistance tests were carried out for mortar specimens. When the rotation per minute of drill bit, tile penetration rate and the bit diameter were 1,300 rpm, 1.40 mm/sec, and 10 mm respectively, the deviation of measured drilling resistance forces was minimal. Under the optimum testing condition, the relationships between drilling resistance and mechanical properties of mortar specimens were shown to be very favorable. The concept of replacing a mean value of resistance farces measured during drilling with the resistance energy was proposed to consider the effects of randomly distributed aggregates inside a concrete material on drilling resistance. When the concept was applied to concrete materials, a favorable relationship between actual compressive strength and drilling resistance energy was also successfully derived.
Application of Linear Curve Fitting Methods for Slug Test Analysis in Compressible Aquifer
Choi, Hang-Seok ; Lee, Chul-Ho ; Nguyen, The Bao ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 99~107
The linear curve fitting methods such as the Hvorslev method and the Bouwer and Rice method provide a rapid and simple means to analyze slug test data for estimating in-situ hydraulic conductivity (k) of geologic material. However, when analyzing a slug test in a relatively compressible aquifer, these methods have difficulties in fitting a straight line to the semi-logarithmic plot of the test data that shows a concave-upward curvature because the linear curve fitting methods ignore the role of the compressibility or specific storage (
) of an aquifer. The comparison of the Hvorslev method and the Bouwer and Rice method is made far a partially-penetrating well geometry to show analytically that the Hvorslev method estimates higher hydraulic conductivity than the Bouwer and Rice method except that the well intake section locates very close to the bottom of the aquifer. The effect of fitting a straight line to the slug test data is evaluated along with the dimensionless compressibility parameter (
) ranging from 0.001 to 1. A modified linear curve fitting method that is expanded from Chirlin's approach to the case of a partially penetrating well with the basic-time-lag fitting method is introduced. A case study for a compressible glacial till is made to verify the proposed method by comparing with a type curve method (KGS method).
The Evaluation of Failure Probability for Rock Slope Based on Fuzzy Set Theory and Monte Carlo Simulation
Park, Hyuck-Jin ;
Journal of the Korean Geotechnical Society, volume 23, issue 11, 2007, Pages 109~117
Uncertainty is pervasive in rock slope stability analysis due to various reasons and subsequently it may cause serious rock slope failures. Therefore, the importance of uncertainty has been recognized and subsequently the probability theory has been used to quantify the uncertainty since 1980's. However, some uncertainties, due to incomplete information, cannot be handled satisfactorily in the probability theory and the fuzzy set theory is more appropriate for those uncertainties. In this study the random variable is considered as fuzzy number and the fuzzy set theory is employed in rock slope stability analysis. However, the previous fuzzy analysis employed the approximate method, which is first order second moment method and point estimate method. Since previous studies used only the representative values from membership function to evaluate the stability of rock slope, the approximated analysis results have been obtained in previous studies. Therefore, the Monte Carlo simulation technique is utilized to evaluate the probability of failure for rock slope in the current study. This overcomes the shortcomings of previous studies, which are employed vertex method. With Monte Carlo simulation technique, more complete analysis results can be secured in the proposed method. The proposed method has been applied to the practical example. According to the analysis results, the probabilities of failure obtained from the fuzzy Monte Carlo simulation coincide with the probabilities of failure from the probabilistic analysis.