Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Engineering Geology
Journal Basic Information
Journal DOI :
The Korea Society of Engineering Gelolgy
Editor in Chief :
Volume & Issues
Volume 19, Issue 4 - Dec 2009
Volume 19, Issue 3 - Sep 2009
Volume 19, Issue 2 - Jun 2009
Volume 19, Issue 1 - Mar 2009
Selecting the target year
Geophysical Investigation for Detecting a Bedrock and Geological Characterization in Natural Slope
Park, Jong-Oh ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 1~8
Geophysical surveys were conducted on an upper part of a natural slope located at Daejeon University. Electrical resistivity and seismic refraction measurements were carried out to obtain information on a weathered zone and internal structure at shallow depth, while AMT measurement a bed rock and geological structure at deep depth. With all the techniques applied, these results show a good correlation between electrical resistivity images and refraction velocity distributions for the characterization of a weathering and geological structure at depth. In particular, AMT survey seems to be the powerful tool for detecting a distribution of a bed rock with deep depth. The combined geophysical investigation produced a detailed image of a subsurface structure and improved well in the interpretation.
Applicability of a Sharp-Interface Model in Simulating Saltwater Contents of a Pumping Well in Coastal Areas
Shi, Lei ; Cui, Lei ; Lee, Chan-Jong ; Hong, Sung-Hoon ; Park, Nam-Sik ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 9~14
In this work applicability of a sharp-interface model to well-scale problems is examined. In coastal areas one of the main concerns in groundwater development is saltwater intrusion. To determine the saltwater intrusion at a well one needs to evaluate the saltwater content from a pumping well. We conducted laboratory sand-tank experiments to determine if a sharp-interface model can simulate the saltwater content of a pumping well. Lateral saltwater intrusion experiments and freshwater lens experiments are conducted. A partially penetrating well and a fully penetrating well are used. Comparison between numerical results and observation results indicates that the sharp-interface model can determine saltwater contents reasonably well. We conclude that a sharp-interface model can be applied to well-scale groundwater flow problems in coastal areas.
Assessment of Seismic Site Response at Hongseong in Korea Based on Two-dimensional Basin Modeling using Spatial Geotechnical Information
Sun, Chang-Guk ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 15~23
The site effects relating to the amplification of ground motion under earthquake loading are strongly influenced by both the subsurface soil condition and geologic structure. In this study, the site effects at the Hongseong area in Korea were examined by both the site investigation including borehole drilling and in-situ seismic tests and the site visit for acquiring geologic information of ground surface. Subsurface of Hongseong area with a major instrumental earthquake event in 1978 is composed of weathered layers of a maximum of 45 m thickness overlying bedrock. A geotechnical information system based on GIS framework was implemented to effectively find out spatial geologic structure of study area and it indicated Hongseong is a shallow and wide shaped basin. Two-dimensional finite element (FE) analyses for a representative cross-section of the Hongseong area were performed to evaluate seismic site responses. From the results of seismic responses, it was observed that the ground motions were amplified during the propagation of shear waves through the soil layer overlying the bedrock and the duration of shaking near the basin edges was prolonged due to the surface waves generated by interactions of shear waves with basin geometry. Furthermore, one-dimensional FE seismic response analyses were additionally conducted for soil sites selected in the basin, and it gives similar results to the two-dimensional seismic responses at most locations in the basin with the exception of the locations near the basin edges, because the basin in this study is very shallow and wide.
Relationship between Rainfall Intensity and Slope Stability based on Numerical Analysis
Lee, Min-Seok ; Kim, Gyo-Won ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 25~31
This study was conducted to characterize the relationship of rainfall intensity and slope stability by using numerical analysis. The maximum precipitation rate for 10 minutes, 1 hour and 1 day was determined as 28 mm, 70 mm and 271 mm, respectively, by investigating 36 years of KMA data. Then slope infiltration analysis was performed to obtain the ground water level in the slope by using computer programming SEEP/W, and slope stability analysis was done for each time step by using program SLOPE/W. The factor of safety was minimized when the slope was saturated under each rainfall intensity; the time required for saturation was 2 hours with 10 minutes rainfall intensity of 28 mm, 7 hours with 1 hour rainfall intensity of 70 mm and 3 days with 1 day rainfall intensity of 271 mm. When accumulated rainfall was 196 mm for the 10minutes rainfall intensity of 28 mm with duration of 2 hours, the factor of safety was decreased to 1.0, while accumulated rainfall of 468 mm and 820 mm for the 1 hour and 1 day rainfall intensity, respectively, was required to reach the factor of safety, 1.0. Since the normalized rainfall intensity was 13 mm and 1.9 mm for 1 hour and 1 day maximum rainfall, respectively, those results showed that the rainfall intensity could have a more effect on the slope stability than the accumulated rainfall.
Analyzed Change of Soil Characteristics by Rainfall and Vegetation
Lee, Moon-Se ; Kim, Kyeong-Su ; Song, Young-Suk ; Ryu, Je-Cheon ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 33~41
In this study, some changes of soil characteristics in a field were analyzed to investigate the effect of heavy rainfall during rainy season. The heavy rainfalls were often induced geohazards like landslides. To do this, the reaching rainfall in the ground surface was investigated according to a condition of vegetation, and the change of soil characteristics induced by infiltrating rainfall was analyzed. The study site is a natural terrain located in Daedeok Science Complex. This site has same geology and soil condition whereas it has different vegetable condition. The rainfall records during the rainy season of 2006 and 2007 were selected. The rainfall records are based on the measuring date from Daejeon Regional Meteorological Administration adjacent to the study site. Also, the rainfall records according to the condition of vegetation were measured using rainfall measuring device made by ourselves. The soil tests were carried out about soil specimen sampled before and after rainfall, and then the change of soil characteristics related to rainfall and vegetation were analyzed. As the result, the density of vegetation was influenced by reaching rainfall quantity in the ground surface, and its influence intensity was decreased with rainfall intensity and rainfall duration. Also, it shows that degree of saturations, water contents, liquidities and shear resistances are directly influenced by heavy rainfalls.
Assessment of Tunnel Displacement with Weak Zone Orientation using 3-D Numerical Analysis
Yim, Sung-Bin ; Jeong, Hae-Geun ; Seo, Yong-Seok ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 43~50
A 3-D numerical analysis was carried out to observe potential effects of orientation of inherent weak zones to tunnel behaviors and stress distributions during tunnel excavation. Weak zones used for the analysis were placed at the upper 1D part from crown, on the crown and on the center of face, using orientations derived from the 6th RMR parameter for assessment of joint orientation effect on tunnel. Mechanical properties of rock mass were derived through a in-situ displacement measurement-based back analysis. Finally, a classification chart for crown settlement with five ranks based on orientation and location of weak zones is suggested.
Fracture Characteristics and Segmentation of Yangsan Fault around Mt. Namsan, Gyeongju City, Korea
Kim, Heon-Joo ; Chang, Tae-Woo ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 51~61
Fractures and segmentation in association with the activities of the Yangsan fault are studied around Mt. Namsan, Gyengju city in the southeastern part of Korea. It is believed that the higher values of joint density and fractal dimension with the approach of the center of the Yangsan fault mean intense fracturing due to the fault activity. The boundary between fault damage zone and host rock is inferred to be placed at about 2.7 km from the center of the Yangsan fault where the values of joint density and fractal dimension abruptly decrease and the orientations of joint are also much dispersed. The small faults within the damage zone of the Yangsan fault are definitely divided into right-lateral and left-lateral strike-slip faults. The former is considered to be formed during the right-lateral movement of the Yangsan fault and the latter during the left-lateral movement. The Yangsan fault is segmented in the study area with obvious evidences as follows: (1) the difference of fault strike between northern and southern segments, (2) The geometry of contractional imbricate fans and syncline plunging
at the end of northern segment, and (3) anticline plunging
at the end of southern segment.
Monitoring System of Rock Mass Displacement and Temperature Variation for KURT using Optical Sensor Cable
Kim, Kyung-Su ; Bae, Dae-Seok ; Koh, Yong-Kwon ; Kim, Jung-Yul ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 63~70
The optical fiber cable acting as a sensor was embedded in the underground research tunnel and portal area in order to monitor their stability and the spatial temperature variation. This system includes two types of sensing function to monitor the distributed strain and temperature along the line, where sensor cable is installed, not a point sensing. According to the results of one year monitoring around the KURT, there is no significant displacement or movement at the tunnel wall and portal slope. However, it would be able to aware of some phenomena as an advance notice at the tunnel wall which indicates the fracturing in rockmass and shotcrete fragmentation before rock falls accidently as well as movement of earth slope. The measurement resolution for rock mass displacement is 1 mm per 1 m and it covers 30 km length with every 1m interval in minimum. In temperature, the cable measures the range of
resolution according to the cable types. This means that it would be applicable to monitoring system for the safe operation of various kinds of facilities having static and/or dynamic characteristics, such as chemical plant, pipeline, rail, huge building, long and slim structures, bridge, subway and marine vessel. etc.
Effects of Well Parameters Analysis Techniques on Evaluation of Well Efficiency in Step-Drawdown Test
Chung, Sang-Yong ; Kim, Byung-Woo ; Kim, Gyoo-Bum ; Kweon, Hae-Woo ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 71~79
Step-drawdown tests were conducted at four pumping Wells, two in porous media and two in fractured rocks, respectively. In general, P = 2.0 suggested by Jacob (1947) is applied to porous media and fractured rocks in terms of drawdowns of step-drawdown test. In an attempt to review problems of linear model (Jacob's graphic method) in interpreting the step-draw down test, the outcomes of well parameters (aquifer loss coefficient (B), well loss coefficient (C) and well loss exponent (P)) calculated from linear and nonlinear model (Labadie and Helweg's least-squares method) were compared and analyzed. The values of C and P calculated from linear and nonlinear models differed according to permeability of aquifer and the conditions of pumping well. The value C obtained from nonlinear models in porous media and fractured rocks is about
times lower than in their linear models, respectively. The value P of porous media obtained from nonlinear model ranged from 2.123 to 2.775, while it ranged from 3.459 to 5.635 for fractured rocks. In case of nonlinear model, well loss highly depends on the value P. At this time, well efficiencies calculated from linear and nonlinear models were
for porous media and
for fractured rocks, showing a significant error according to chosen models. In nonlinear model, it was found that the regression analysis using the least squares method was very useful to interpret step-drawdown test in all aquifer.
Variations of Longitudinal Moments for a Contaminant Transport in Physically and Chemically Heterogeneous Media
Seo, Byong-Min ; Jung, Joon-Oh ; Kim, Young-Woo ; Hwang, Seung-Min ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 81~88
Two dimensional Monte-Carlo simulations of a non-reactive solute plume in isotropic porous media which are physically and chemically heterogeneous are conducted to determine the variations of moment. Retardation factors of 1, 2 and 5 are given to ascertain how the second moments are changed as adsorption increased. Retarded longitudinal second spatial moment,
, increased during the transport process and as the dimensionless lengths of line plume source,
decreased as the retardation factors increased, and the simulated moments fit well to the first-order analytical results. Retarded longitudinal plume centroid variance,
, decreased as the dimensionless lengths of line plume source,
, increased and as the retardation factor increased. The result indicates that the uncertainty about the plume center decreased, and the ergodic condition for the second spatial moments is far from reaching. Simulated longitudinal one particle displacement covariance,
, well consistent with the first-order analytical results for the three degrees of retardation factors of 1, 2 and 5 respectively. It is, consequently, concluded that the retarded longitudinal second moments could be produced by stochastic simulation, and that the first-order analytical results definitely provides very close values of the longitudinal retarded moments.
Case Study on Application of Geophysical Survey in the Weathered Slope including Core Stones
Hong, Won-Pyo ; Kim, Jae-Hong ; Ro, Byung-Don ; Jeong, Gyo-Cheol ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 89~98
Existence of core stone at the inside of the Rock mass is reacting as unstable element. In particular, in case of the cut slope, even when it is not exposed, slope's discontinuity increases or strength level decreases depending on the difference in the weathering grade when it comes to the core stone, and reacts as an important element of the slope movement such as slope's rock fall or collapse. As for the slope that is subject to study, incision was completed after 20 years or so, and parts of the slope reinforcement was completed, but frequent rock fall occurs despite small amount of rainfall, and permanent stability measures are urgent. Refractional seismic survey and geological survey results were compared and analyzed, and reliability was improved by complementing the two survey methods, and stereo-graphic projection using DIPS program was conducted to analyze the characteristics of oore stone in the weathered soil slope.
Development of an Evaluation Chart for Landslide Susceptibility using the AHP Analysis Method
Chae, Byung-Gon ; Cho, Yong-Chan ; Song, Young-Suk ; Seo, Yong-Seok ;
The Journal of Engineering Geology, volume 19, issue 1, 2009, Pages 99~108
Since the preexisting evaluation methods of landslide susceptibility take somehow long time to determine the slope stability based on the field survey and laboratory analysis, there are several problems to acquire immediate evaluation results in the field. In order to overcome the previously mentioned problems and incorrect evaluation results induced by some subjective evaluation criteria and methods, this study tried to develop a method of landslide susceptibility by a quantitative and objective evaluation approach based on the field survey. Therefore, this study developed an evaluation chart for landslide susceptibility on natural terrain using the AHP analysis method to predict landslide hazards on the field sites. The AHP analysis was performed by a questionnaire to several specialists who understands mechanism and influential factors of landslide. Based on the questionnaire, weighting values of criteria and alternatives to influence landslide triggering were determined by the AHP analysis. According to the scoring results of the analysed weighting values, slope angle is the most significant factor. Permeability, water contents, porosity, lithology, and elevation have the significance to the landslide susceptibility in a descending order. Based on the assigned scores of each criterion and alternatives of the criteria, an evaluation chart for landslide susceptibility was suggested. The evaluation chart makes it possible for a geologist to evaluate landslide susceptibility with a total score summed up each alternative score.