• 지질공학
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• 제32권1호
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• pp.85-99
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• 2022

Rock discontinuities, as weak interfaces in rock, control mechanical properties of rock mass. Presence of discontinuities complicates the engineering properties of rock, which is the root of anisotropy and heterogeneity that have nonnegligible influences on the rock engineering. Morphological characteristics of discontinuities in natural rock are an important factor influencing the mechanical properties, particularly roughness, of discontinuities. Therefore, the accurate measurement and characterization of morphologies of discontinuities are preconditions for studying mechanical properties of discontinuities. Taking discontinuities in red sandstone as research objects, the research obtained three-dimensional (3D) morphologies of discontinuities in natural rock by carrying out 3D morphological scanning tests. The waviness and roughness were separated from 3D morphologies of rock discontinuities through wavelet transform. In addition, the calculation method for the overall slope root mean square (RMS) as well as slope RMSs of waviness and roughness of 3D morphologies of discontinuities considering the shear direction was proposed. The research finally determined an evaluation method for 3D morphologies of discontinuities by quantitatively characterizing 3D morphologies with the mean value of the three slope RMSs.

• Geomechanics and Engineering
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• 제6권4호
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• pp.403-418
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• 2014

There are around 6700 millions tons of perlite reserves in the world. Although perlite possesses pozzolanic properties, it has not been so far used in soil stabilization. In this study, stabilization with perlite and lime of an expansive clayey soil containing smectite group clay minerals such as montmorillonite and nontronite was investigated experimentally. For this purpose, test mixtures were prepared with 8% of lime (optimum lime ratio of the soil) and without lime by adding 0%, 10%, 20%, 30%, 40% and 50% of perlite. Geotechnical properties such as compaction, Atterberg limits, swelling, unconfined compressive strength of the mixtures and changes of these properties depending on perlite ratio and time were determined. The test results show that stabilization of the soil with combination of perlite and lime improves the geotechnical properties better than those of perlite or lime alone. This experimental study unveils that the mixture containing 30% perlite and 8% lime is the optimum solution in stabilization of the soil with respect to strength.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 제7회 특별심포지움 논문집
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• pp.155-175
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• 2005

지반의 동적 변형 특성인 전단파 속도(Vs), 압축파 속도(Vp), 그리고 그에 따른 포아송 비(v)는 내진 설계나 내진 성능 평가 외에도 구조물의 거동 평가에 필요한 매우 중요한 지반 정수이다. 지난 수 십 년 동안 이러한 지반 정수를 효율적이고 정밀하게 측정하기 위해 여러 가지 검측공 탄성파 시험 기법들이 개발 및 적용되어 왔다. 본 연구에서는 가장 신뢰성이 높은 현장 탄성파 기법인 크로스홀 탄성파 시험 기법을 지반 동적 물성을 획득하기 위한 기법으로 선정하였다. 지하수위 존재 여부에 관계없이 토사뿐만 아니라 암반을 대상으로 크로스홀 시험을 성공적으로 수행할 수 있도록 연직 시추공 안에서 지반에 대한 횡방향 가진이 가능한 스프링식 발진 장치를 개발하고, 두 곳의 기존 항만 부두 부지와 두 곳의 신규 LNG 저장 시설 부지로 구성된 국내 세 지역을 대상으로 크로스홀 탄성파 시험을 실시하였다. 대상 부지에서의 횡방향 가진의 크로스홀 시험으로부터 깊이별 Vs, Vp 및 v와 같은 지반 동적 특성을 효율적으로 결정하였으며, 적용 대상 시설물인 기존 항만 부두 시설물의 내진 성능 평가 그리고 신규 LNG 저장 시설물의 내진 설계를 위한 근본 자료로 제시하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1994년도 가을 학술발표회 논문집
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• pp.191-198
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• 1994

This paper deals with a feedback system for the estimation of geotechnical parameters in underground construction works. The Ordinary Least Square (OLS) Optimization Method is utilized and combined with Finite Element Program so that optimum values of ground properties can be estimated. The preperties that can be estimated are Young's and Brown's failure criteria is proposed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.182-185
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• 2007

It is important to identify the fault for solving the problem about slope failure and landslides. This brief report is to review occurrence and characteristics of the fault. Also, this is to introduce the geotechnical characteristics and properties of the fault and suggests how the fault affects to the cut slope stability and propose countermeasures with respect to the fault.

• 한국유체기계학회 논문집
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• 제19권3호
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• pp.29-32
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• 2016

A series of laboratory tests were conducted to investigate the geotechnical engineering characteristics of muskeg soil for construction machinery widely distributed in cambridge region in Canada which makes problems in construction works. Physical characteristics of cambridge region muskeg soil were measured in terms of such categories as nature water content, organic content, specfic gravity, liquid limit, and plasticity index. As the test result, it was found that nature water content, organic content, specific gravity, liquid limit, plasticity index, and compression strength were 50.8~343.8%, 12.1~42.5%, 1.76~2.57, 46.6~440.2%, 25.6~280.5, $0.665{\sim}1.537kg/cm^2$, respectively.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1996년도 봄 학술발표회 논문집
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• pp.259-264
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• 1996

• 한국지반공학회논문집
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• 제24권8호
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• pp.111-123
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• 2008

지반공학 문제는 많은 불확실한 요인을 내포한다. 이러한 불확실성 중 일부는 해석 수행과정에 필요한 지반 물성의 변동성과 관련이 있다. 본 연구에서는 지반물성의 공간적 변동성을 고려한 확률론적 해석을 수행할 수 있는 절차를 제시하였다. 제시된 방법은 유한차분 해석기법과 랜덤필드 이론을 확률론적 해석기법에 통합하게 된다. 지정된 입력 확률분포함수와 자기상관함수를 따르는 non-Gaussian 랜덤필드를 생성하기 위하여 Karhunen-$Lo{\grave{e}}ve$ 전개법을 사용하였다. 생성된 랜덤필드를 이용하여 확률론적 응답을 얻기 위해 Monte Carlo 시뮬레이션을 수행하였다. 지반의 공간적인 변동성에 기인하는 불확실성의 효과를 연구하기 위하여 대상 기초의 침하량과 지지력에 대한 일련의 해석을 수행하였다. 해석결과는 지반공학 문제에서 불확실성을 고려할 수 있는 관점을 제시하며 확률론적 평가의 결과에 미치는 지반물성의 공간적 변동성의 중요성을 보여준다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.434-478
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• 2006

Stress waves have been used for geophysical and geotechnical applications for more than 50 years. The early-stage applications were simply based on travel-time measurements of stress waves and limited to site characterization. Currently stress-wave techniques are expanded to monitoring processes for grouting of damaged geotechnical structures, compaction of embankment, and deformational analyses for static geotechnical problems. Seismic techniques used to be good enough for rough estimators of engineering properties. Nowadays, the sophisticated modeling theory of stress-wave propagation substantially improved reliability and accuracy of the seismic techniques. In this paper, difficulties involved in currently available seismic techniques are discussed and analyzed. Herein some recently-developed non-intrusive seismic techniques, which make optimal use of stress waves for further improvement of reliability and accuracy, are also presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1562-1571
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• 2005

The use of geogrid for SRW systems and bridge abutment has increased rapidly over the past 10 years in Korea. The concept of segmental retaining walls and reinforced soil is very old and for example The Ziggurats of Babylonia(i.e. Tower of Babel) were built some 2,500 to 3,000 years ago using soil reinforcing methods very similar to those described in current design. Modern SRW(Semental Retaining Wall) units were introduced in 1960's as concrete crib retaining wall systems. In this paper, the friction properties between segmental concrete units and geogrid are investigated by performing various tests.