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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Engineering Geology
Journal Basic Information
Journal DOI :
The Korea Society of Engineering Gelolgy
Editor in Chief :
Volume & Issues
Volume 1, Issue 1 - Sep 1991
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Geotechnical Considerations in Tripoli Sub-region, Libya
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 2~10
Some geotechnical considerations might be suggested to the construction performance from the school and the housing projects in Tripoli sub-region, Libya. The subsurface informations were compiled from the site investigation reports, for which more than 700 borings and lots of laboratory test had been conducted from 1984 to 1986. Most subsurface of 10 meter depth in the Jafara plain consists of medium dense silty sand. Some ground in the plain have poor top soil with interbedded calcarenite or limestone. The shallow subsurface is found to be very poor soil in the southern mountain range. Weak soil is hardly found except in the sabkha area. In general, natural silty sand layer may have a presumed bearing capacity of more than 150kN/
, where spread or strip footing is applied. Proper fine aggregate and natural coarse one are restricted in Tripoli sub-region. Coarse aggregate is generally supplied from the dolomite quarry.
Unhardening Phenomena of SCW constructed in Organic Soil
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 11~18
A series of laboratory tests were conducted to verify the unhardening phenomena of Soil-Cement Wall (SCW) and the results are presented in this paper. Specimens are prepared by mixing the site soil with cement and additives at a various ratio. The hydration of the cement mixed with the in-situ soil was retarded due to the higher organic content of the soil. In order to remove the influence of the organic matters in hydration reaction, calcium chloride (CaCI
) was added as an acceleration additive at a different ratio. The optimum ratio of the calcium chloride for the higher SCW strength was determined as 2% of cement weight. The strength, however, was decreased by adding 4 and 6% of the additives. The effect of other additives, NaOH and NaSiO
, were also investigated and the results are included. The strength of SCW by adding sodium hydroxide was lowered. And the short term strength by adding sodium silicate was increased but the long term strength was decreased.
Engineering Geological Characteristics of volcanic rocks of the Northwestern Cheju Island, Korea
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 19~37
The geology of the northwestern Cheju Island consist of Pleistocene to Holocene volcanic rocks which could be devided into basalt layers, the Sungsan Formation composed mainly of volcaniclastic debris exposed along the shoreline, and more than 30 cinder cones. Columnar joints and vesicles are dominant in the basalts of the Pyeosunri and the Sihungri basalt Formations. Volcaniclast and clay layers are intercalated in basaltic layers. When volcaniclast of the interlayers would be swept away by ground water and some caves of channel shape would be formaed. Overlying lavas cracked by columnar joints could be easily destroyed, collapsed and/or sunk. Geomechananical nature of the rocks such as strength may be controlled by the vesicularity(size, shape, and orientation of the vesicles) of the rocks. On the basis of vesicularity as a factor of strength, the effective strength ratio(Ke) could be calculated as Ke=0.3-0.72, in which the smaller Ke value reflects the lower in internal stress. In the studied area, the strength of the rocks tends to decrease as increasing in altitude of provenance of the rocks. The rocks in the area show relatively low values in angle of failure strength(
) ranging from 10
. In conclnsion, the rocks in question, majority of which the critical value exceeds 0.33, belong to the unstable rocks in the aspect of engineering geology.
Analysis of Ground Behavior applied to the Design of Underground Opening Structures
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 38~53
The design of underground cavern is basically governed by the mechanical properties of ground mass distributed around excavation. It is seldom possible to consider all the factors of ground mass properties in the evaluation of ground mass behavior as well as to classify those factors to a simple category. Until computer sciences have developed to calculate complex and laborious mechanical simulation of underground openings, ground behavior was quantitatively and qualitatively evaluated using empirical classification system. In this paper, analysis methods of ground behavior for underground cavern using the prediction of loosening zone, empirical method derived from rock mass classification and element stress analysis are described with chronological sequence.
The Anisotropic Mechanical Characteristics of the Metamorphic Rocks Distributed in the Samkwang-Mine Area, Cheongyang, Chungnam
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 54~67
In geological media with anisotropic properties, the strength anisotropy in intact rock is the most important issue in engineering aspects. Point-ioad(P/L) strength test designed to estimate the uniaxial compressive strength(
) can be used to evaluate the anisotropic strength characteristics of rocks. The relationship between
and P/L strength indices(I
), obtained from the banded gneisses distributed in the Cheongyang area, varies depend mainly on the dip angle(
) of foliation. The axial P/L strength indicies(I
) decreases with the increment of
, whereas diametral P/L strength indices(I
) increase with it. However, the
decreases with the increments of
below about 40
, but it increases with the increments of
over about 40
in general. The correlation between
is related to the Isa withing low angle(
) and the I
within high angle (
), respectively. The ratios of I
are obtained as 11 to 14 in the the gneisses in the study area. The ratio of 24, which is generally adopted value, cannot always be truthworth to the gneisses in the study area. The ratio for the dykes, however, show a good correlation as 21 to 24.5 and, the value of 24 can be used for a homogeneous and isotropic materials such as dykes.
A Numerical analysis of Underground Repository Cavern in Korean Crystalline rocks
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 68~84
A numerical analysis using Universal Distinct Element Code program for the nuclear waste disposal cavern has been performed for a typical Korean crystalline rock condition with same geometry of Swedish low and intermediate nuclear waste disposal repository(S.F.R). The stress concentration, displacement and safety factor for the typical single cross section of cavern, 5 caverns and a silo are analyzed.
Digital Processing for Multichannel Seismic Data(I) -Marine Reflection Data Processing-
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 85~108
Marine seismic processing is characterized by a great amount of data, several professional processing steps, and various parameters to be decided in each step. In general, adequate processing sequence and optimum parameters are obtained through test processing with sample set of data representing the whole group. The sequence and parameters are then applied in processing the whole data. In this paper, optimum processing sequence and parameters for the data acquired in Korean continental shelf are examined through test processing with real data. Finally, a good-quality migration section is produced using those sequence and parameters decided on the basis of the test results.
Microtremor and Underground Structure
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 109~120
Applications of microtremor to geological engineering are widely reviewed and observed microtremors are processed to show evidences of close relationship between the predominant periods of microtremor and underground structure. The ground vibrates continuously at all times and the elastic vibration is called microtremor (0.5-20Hz) or microseisms (0.01-0.1Hz) according to their frequency range. The vibration is believed to have propagative nature like those of the dispersive surface waves or multireflected shear waves. Microtremors were recorded at selected thress places of which subsoil structures are well distinguished in the Kyongsang Sedimentary Basin. It is found that the underground structures estimated from microtremor analysis coincide well with the known structures. The microtremor analysis of the long period range can be an inexpensive and effective tool in geological engineering for the evaluation of the underground structure, site-specific reponse spectrum, and seismic microzonations.
A Study on the Focal Mechanism of the Hongsung Earthquake from the P-Wave Polarity Distributions
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 121~136
The focal mechanism of the Hongsung Earthquake (1978. Oct. 7, M
=5.0, Latitude 36.62N, Longitude 1 26.67E) was evaulated using the polarity distribution of the P-Waveforms. Through the non-linear computer process, the compatibility of polarity distributions of the 9 P-Waveforms observed at teleseismic distances from the Hongsung Earthquake epicenter was investigated to those of the focal mechanism determined from the varying strike, dip and rake angles. The resultant values for the strike and dip angle of the principal fault plane, which apparently matches very well the sunface lineament of the Hongsung region, are determined to be about 247 degree and 78 degree with uncertainties, respectively. However, the rake angle of the focal mechanism has wide range of 40 degree to 160 degree, which is mainly due to the poor coverage of the azimuthal angle of the observed seismic stations. Due to the consistency of principal stress axes, the resultant focal mechanism could support the current stress regime of that region, which may be caused by subduction of the Pacific Plate under the Eurasia Plate along the Japan Trench. It also provides information of seismic source characteristics of the part of the Korean Peninsula for aseismic design criteria such as Site Specific Response Spectrum and Strong Ground Motion Time History for the nuclear power plants and related nuclear waste disposal facility sites.
Groundwater Flow Characteristics in Crystalline Rock : Review
The Journal of Engineering Geology, volume 1, issue 1, 1991, Pages 137~145
Groundwater flow in fractured rocks generates many challenging problems to scientist and engineers in the projects related to oil and geothermal reservoirs, subsurface contaminations and underground openings. To circumvent these problems, the numerical simulation of groundwater system is used as an established tool in these days. Discrete modelling approach emphasizes geometric parameters, aperture and transport properties of fracture. On the other hand, continuum modelling approach uses the parameters formulated in a way of average hydraulic property. In recent years, the results of field observations from underground opening indicate that groundwater in rock mass flows in a channel form. The channel flow is postulated as the result of the combined effects of geometric pattern and aperture variation.