• Explosives and Blasting
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• 제28권2호
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• pp.1-16
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• 2010

This study focuses on the phenomenon that the blast damaged zone developed on rock slope surfaces can be affected by joint characteristics rather than by explosive power when the pre-splitting is applied to excavate a jointed rock slope. The characteristics of rock joints on a slope were investigated and categorized them into 4 cases. Also an image processing system has been used for comparing the distribution pattern of rock blocks. From this investigation, it was found that the rock blocks bigger than 2,000 mm occupied 42% in the case of single joint set and it showed the well efficiency of pre-splitting blast. In cases of 2~3 parallel joint sets and 2~3 intersecting joint sets are developed on rock surfaces, the rock blocks in the range of 1,000~2,000 mm occupied 43.6% and 35.8%, respectively, and it showed that the efficiency of pre-splitting was decreased. When more than 3 joint sets are randomly developed, however, the rock blocks in the range of 250~500 mm occupied 35% and there was no block bigger than 1,000 mm. This denotes that the blasting with pre-splitting was not effective. The numerical analysis using PFC2D showed that the blast damaged zone in a rock mass could be directly influenced by the pre-splitting. It is, therefore, required to investigate the discontinuity pattern on rock surfaces in advance, when the pre-splitting method is applied to excavate jointed rock slopes and to apply a flexible blating design with a consideration of the joint characteristics.

• Tunnel and Underground Space
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• 제2권1호
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• pp.123-151
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• 1992

“Norwegian Tunnelling in General" will cover the following subjects : - Short introduction to the geology of Norway - Major considerations in rock installations - Hydropower plants, roads, tunnels, oil and gas storage in rock, drinking water storage, sewage plants, frozen food storage, defence and civil defence projects, including sports arenas and swimming pools, etc.

• Tunnel and Underground Space
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• 제5권1호
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• pp.41-47
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• 1995

터널의 설계를 용이하게 하기 위하여 ROMES 프로그램을 개발하였다. 개발된 프로그램의 타당성 검토를 위하여 기존 Classextltmxpa으로 검증한 결과 높은 상관관계를 얻었으며 기존의 암반분류 사례에 적용한 결과 정밀하고 객관적인 분류가 가능한 것으로 밝혀졌다.

• Tunnel and Underground Space
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• 제6권4호
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• pp.335-341
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• 1996

This fundamental study analyzes the relationship between rock thermal properties and psychrometric properties in underground space and has a ultimate goal to develope technologies for predicting major environmental variables. The study is divided into 2 subjects (1) developement of a basic model for predicting temperature and humidity, (2) analysis of the validity of the model through application to a local underground storage space for military supplies. The basic model is built for the network of tunnel-shaped underground spaces. The model takes into account rock thermal properties and changes in moisture content in the air due to condensation/evaporation on the rock surface. Using lumped-parameter analytical method, heat flux from or to the surrounding rock is calculated and then the psychrometric properties(air quantity, pressure, temperature, humidity) are estimated through network simulation. The model can be utilized regardless of the tunnel type. The study site is a local storage space built in rock, mainly granite gneiss and quartz-porphyry. It is a U-shaped tunnel, 593.5m long and 6x6.5m wide. Relative humidity inside has to be strictly controlled under 55% to avoid erosion of a certain types of supplies stored in 6 chambers with the capacity of 300~1.000 ton. The thermal conductivity varies between 2.734 and 2.779W/m$^{\circ}C$ and the thermal diffusivity is in the range of 1.119 and $1.152{\times}10^{-6}\;m^2/s$ the specific heat between 910 and $920\;J/kg^{\circ}C$. Relative errors of the predicted values of dry/wet temperature and relative humidity are 0.8~3.0%, 0~7.5% and 0~7.0%, respectively. Apparent errors associated with the rock surface temperature seems to be partly due to the intrinsic limitations in the infrared thermometer used in this study.

• The Journal of the Petrological Society of Korea
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• 제27권2호
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• pp.105-108
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• 2018

This study was on the rock garden among the school gardens as survey of 122 schools(60 elementary schools, 34 middle schools and 28 high schools) during 16 months from March 2017 to June 2018, There were 36 rock gardens (29.51%). 40% elementary schools and 18.18% secondary schools (middle and high schools) had the rock gardens. 3 items were surveyed; Was the rock sample in the rock garden related to the curriculum? Was the name of sample correct? Was the content of a sample's exhibition panel suitable? Elementary schools showed 36.7% in response to 'Was the rock sample in the rock garden related to the curriculum', 55.1% in response to 'Was the name of sample correct?' and 55.5% in response to 'Was the content of a sample's exhibition panel suitable?' Secondary schools showed the average 83.9% correlation in the aspect of curriculum, 82.8% accuracy in the aspect of sample name and 84.1% suitability in the aspect of the content of a sample's exhibition panel.

• Journal of The Geomorphological Association of Korea
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• 제20권3호
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• pp.65-77
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• 2013

This study investigated and analyzed the topographic landscape resources of Mureung Valley in Donghae-si from the viewpoint of geotourism in order to suggest the tourism contents and tour course. A total of 29 topographic landscapes were observed; these are broadly divided into 4 features including weathering landform, mountainous landform, fluvial landform, and structural landform. Major topographies are fluvial landform (13) and weathering landform (12). At least 19 topographies (14 sites, 19 topographic landscapes) are currently used as tourism resources, with 10 topographies having potential to be developed as new tourism resources. The 10 topographic landscapes are as follows: (1) Jamryong Bawi (Hidden Dragon Rock), (2) Janggipan Bawi (Korean Chessboard Rock), (3) Nurungji Bawi (Parched Rice Rock), (4) Damjang Bawi (Fence Rock), (5) Gyedan Bawi (Stairs Rock), (6) Heundeul Bawi (Rocking Rock), (7) Jeopsi Bawi (Dish Rock), (8) Dol Umul (Stone Well), (9) Jogak Bawi (Carved Rock), and (10) Dubu Bawi (Topu Rock). The topographic tour course can be divided into 3 routes considering accessibility and time. Route 1 is a basic one that anyone can easily use; Route 2 and 3 can be used by visitors who have more time to spare or who are more active.

• Explosives and Blasting
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• 제16권3호
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• pp.16-24
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• 1998

Methods of Rock fragmentation are used rock of housing repair development at KU-SAN DONG area in seoul Youn-Pyong Ku. So, Theorical analyses of the effect of vibration and frequency on structural damage around old housed also discussed. The results can be summarized as follows: 1. A area(Rock area not more than 15m Ku-San Mention) Some Empirical equations were obtained $V=K\{{\frac{D}{W}}1/3\}^{-n}$ where the values for n and K are estimated to be -1.64 and 94 respectively, this values were obtained only theorical analyses. If we have 125g charge this area is impossible blasting operation, so this area must be worked by SRS(Super Rock Splitter) method. 2. B area(Rock area from 15m to 25m in a boundary line from Ku-San Mention) This area charge is about 125g in a delay time by some empirical equation s. So, this area can be blasting operations by small charge. 3. C area(Rock area from 25m to 35m in a boundary line from Ku-San Mention) This area charge is about 500g in delay time by some empirical equation s. So, this area can be blasting operations by middle charge. 4. D area(Rock area more then 35m in a boundary line from Ku-San Mention) This area charge is about 1000g in a delay time by some empirical equation s. So, this area can be blasting operations by middle charge.

• Tunnel and Underground Space
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• 제6권1호
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• pp.19-29
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• 1996

Back analysis model, capable of calculating the mechanical properties and the in-situ stresses of jointed rock mass, was developed based on the inverse method using a continuum theory. Constitutive equation for the behavior of jointed rock contains two unknown parameters, elastic modulus of intact rock and stiffness of joint, hence algorithm which determines both parameters simultaneously cannot be established. To avoid algebraic difficulties elastic modulus of intact rock was assumed to be known, since the representative value of which would be quite easily determined. Then, the ratio ($\beta$) of joint stiffness to elastic modulus of intact rock was assigned and back analysis for the behavior of jointed rock was carried-out. The value $\beta$ was repeatedly modified until the elastic modulus from back analysis became very comparable to the predetermined value. The joint stiffness could be calculated by multipling the ratio $\beta$ to the final result of elastic modulus. Accuracy and reliability of back analysis procedure was successfully testified using a sample model simulating the underground opening in the jointed rock mass. Applicability of back analysis model for the underground excavation in practice was also verified by analyzing the mechanical properties of jointed rock in which underground oil storage cavern were under construction.

• Korean Journal of Agricultural Science
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• 제43권4호
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• pp.634-640
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• 2016

The objective of this study was to evaluate the effectiveness of using HR-GC/MS for the rapid screening of dieldrin residues in soils. Persistent organic pollutants (POPs) of organochlorine pesticides such as dieldrin, were analyzed in sedimentary rock and granite rock collected from greenhouses, Niigata, Japan. Dieldrin remains in Japanese farming soils, more than 40 years after their use as insecticides was prohibited. The averages in soil moisture ranged from 2.79% to 7.20% in soils derived from sedimentary rock and from 25.59% to 31.40% in soils derived from granite rock. Mean concentrations of dieldrin residues in sedimentary rock and granite rock were $39.7ng\;g^{-1}$ and $40.51ng\;g^{-1}$, respectively. Dieldrin residue was detected at a slightly higher concentration in granite rock than sedimentary rock samples. There was no consistency between the two soils or between surface and subsurface soils. The coefficients of variation of the two soils were 10.6% and 8.7%, respectively. These results suggest that our high-resolution mass spectrometry detector (HR-GC/MS) is effective at analyzing residual organochlorine pesticides in soil. In order to increase the precision and sensitivity for chemical analysis of POPs, high-resolution gas chromatography coupled with a HR-GC/MS is highly recommended.

• Tunnel and Underground Space
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• 제12권1호
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• pp.1-9
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• 2002

Recently, the use of image analysis methods and commercial equipments has been extensively increased in the field of rock engineering. However the problem of errors involved in the image acquisition and subsequent analysis procedure has been frequently neglected. In addition there has been few studies dealing with this problem. So proper color calibration method is needed to be developed for the objectivity and improvement of reliability on image analysis of rock. Color calibration method using standard color rendition chart was adopted on this study. Color calibration and error analysis were carried out for the image acquired from granite rock samples. As a result, comparison among other rock images and improvement of reliability on whole analysis were possible.