• Tunnel and Underground Space
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• v.11 no.2
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• pp.182-189
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• 2001

Rockmass properties have great influence on blasting performance so that it cannot be overemphasized to analyze rockmass properties and to perform blast design based on them. Up to the present, however blast design is performed either considering only uniaxial compressive strength of intact rock or using RMR classification as a blast ability classification scheme. In this paper Ashby's approach is adopted to evaluate blast index. In addition. rockmass classification for the blast design based on joint survey results and pattern design procedure are added to Ashby's original approach. With this extended approach, blastability can be classified considering joint properties and objectiveness of evaluated blast index can be confirmed. This approach is anticipated to enhance the tunnel blast design by considering joint properties and classifying the rockmass for blast design.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.61-70
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• 2013

This paper presents the results of a two-dimensional finite element analysis of end bearing capacity of single pile installed in fractured rock mass. A number of cases were analyzed using Hoek-Brown criterion that can consider the condition of rock joints. Considering a wide range of joint conditions in which the pile is embedded into the rock, GSI was set as a main parameter. And the effects of pile diameter, unconfined compressive strength of rock and Hoek-Brown constant $m_0$ were considered. Based on parameter study, end bearing load factor graphs were suggested.

• Tunnel and Underground Space
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• v.10 no.2
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• pp.211-217
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• 2000

In this, study, some laboratory tests and in-situ test were performed for Taegu area. Test blasting was conducted to determine blasting vibration coefficients. The uniaxial strength of rocks vary widely from weathered rock to extremely hard rock. Boasting vibration coefficient, K and n were 114.8, 1.48 for Sungseu site, where rocks show weathered to medium strength.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.340-343
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• 2005

국내 지하수의 지속적인 개발을 위한 훌륭한 방안이 될 수 있는 Stygofauna를 이용한 biological indicator system 개발을 위해 국내 지하수를 대표할 수 있는 국가지하수관측망 약 200여 개소를 선정하여 국내 지하수 미소생물 분포를 조사하였다. 전국의 지하수 생물 채집 결과, Cyclopoida(41.4%)가 우리나라 지하수 생태계에서 가장 전형적인 동물로 나타났으며, 암반대수층보다 에너지와 유기물이 충분한 충적대수층에서 동물의 밀집도가 두 배 가량 높게 나타났다. 생물 분포 또한 충적대수층과 암반대수층이 약간 다르게 나타났다. 권역별 동물 개체수 비교 결과, 금강권역에 비해 영산강과 낙동강권역은 종과 개체수가 적게 나타났다.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.211-218
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• 2002

TBM 터널굴진시 공법적합성을 평가하기 위한 현장조사 및 물리탐사와 세부지질조사를 수행하였다. 해당지역은 부산시 진구 가야동과 동구 수정동이며 인근 수원지인 덕정정수장에서 생산하는 수돗물을 수정산 배수지까지 확대 공급함으로서 송수공급 계통의 이원화로 안정적인 수돗물공급을 수행하기 위한 배수지터널이다. 이론적으로 굴착속도는 암반의 반발경도, 일축압축강도, 석영함량 및 각종 지질특성에 의하여 좌우되는데, 실지 시공에 있어서는 현장여건상 지질조건이나 일축압축강도등 한정된 자료들을 토대로 시공에 임할 수밖에 없다. 이러한 한계를 극복하기 위한 모형개발을 목표로 본 연구에서는 다양한 현장시험을 토대로 한 TBM 굴진 적합성을 검토하고자 하였다. 국내 시공경험상 및 지질특성만을 고려 할 때 본 과업구간의 TBM 적용성은 양호할 것으로 판단하였으나, 뚜렷한 근거에 의거하지 않은 설계는 시공단계에서 엄청난 손실을 야기하게 되므로 보다 상세한 검토를 수행하게 되었다. 본 연구에서는 TBM 공법선정의 적합성을 검토하기 각종 조사 자료들을 정리하였고, 국내시험의 한계점들을 극복하기 위한 적합한 모형개발의 필요성을 제시하고자 하였다.

• Journal of the Korean Geotechnical Society
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• v.17 no.2
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• pp.13-20
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• 2001

외부하중의 작용방향에 의한 암반의 강도 및 변형이 달라지는 것을 강도 이방성, 또는 변형이방성이라 정의되어 진다. 강도 또는 변형 이방성은 층리진 퇴적압, 박층모양의 변성암, 균일하게 절리가 나있는 암석에서 흔히 볼 수 있다. 이러한 강도이방성에 대한 경험적 및 이론적 관점에서의 파괴 규준은 Jaeger(1960), McLamore와 Gray(1967), Donath(1972), Nova(1980), Hoek과 Brown(1980), Ramamurthy(1985)등 많은 학자들에 의해서 연구되어져 왔다. 본 논문에서는 셰일에 대한 삼축 압축시험을 통하여 층리각도에 따른 강도 이방성을 확인하고, 점착력, 내부 마찰각 및 재료상수의 물성치를 회귀분석을 통하여 구하였다. 또한, 수정된 Hoek과 Brown, Ramamurthy 등의 식을 통해 기존의 파괴규준식 및 수정된 식이 강도이방성적 특성을 나타내는 이 지역 셰일에 대한 적용가능성을 논하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.473.2-473
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• 2001

• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.102-108
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• 2006

• Journal of the Korean GEO-environmental Society
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• v.4 no.4
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• pp.45-51
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• 2003

Grouting materials in rock is grouted as vein type along the fault surface by the other way for soil and allow a change of characteristics in rock faults as a result of that. Therefore the deformation characteristics of rock faults after grouting differ as a direction and characteristic of grouted fault and stress condition of field rock. Thereby it must be analyzed the effect for deformation of rock according to characteristics of rock faults and characteristics of grouting materials to accurately evaluate the reinforced effect by grouting. But grouting method used in field until present depends on experience of workers, and inspection for those effects are evaluated by measurement of elastic wave velocity, permeability tests and etc. in field. In this study, it was investigated that the effects for shear characteristics of maximum shear strength, residual shear strength and etc. by comparison and analysis of test results which were worked by direct shear tests of rock faults with changing a type of grouting materials and the grouting depth(t) for average width(a) of fault surface roughness when OPC(Ordinary Portland Cement) and Micro cement was grouted in fault surface of field rock to evaluate characteristicsof the shear deformation for rock fault surface of dam by grouting.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.683-689
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• 2017

We have carried out the development for hydraulic breaker which can be operated by optimal mode with ICT convergence technology. This developed system can predict the rock properties. Moreover, this system can maximize the energy efficient with intelligent control of hydraulic system. In order to provide the optimal impact force, this system can measure the descending depth of piston with the proximity sensor and discriminate the rock properties with the measuring data and control the piston stroke using solenoid valve eventually. In addition, we have developed the controller, display module and operating device for cascade (multi-level impact) system and applied the module which can communicate each system by wireless communications. In conclusion, the control system which can control the multi-level impact in accordance with strength of rocks has been developed and approved by several field tests.