• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.259-264
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• 2002

In this study the shear strengths of a poorly grad ed rock material(d/sub max/≤50.8mm, C/sub u/=1.86) were determined by large direct shear test and large triaxial test. The obtained stress-strain curves by the above large shear tests for the rock materials are similar to the loose sand's or normally consolidated clay's curve, in which the peak strength does not appear obviously. And for the uniformly graded rock material the shear strength by large direct shear test may be overestimated around 1.54∼1.70 times that of large triaxial test.

• 한국농공학회논문집
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• 제52권3호
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• pp.73-79
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• 2010

In the present study, the loading frequency dependencies of cyclic shear strength and elastic shear modulus of reconstituted clay were examined by performing undrained cyclic triaxial tests and undrained cyclic triaxial tests to determine deformation properties. The result of undrained cyclic triaxial test of reconstituted and saturated clay shows that a faster frequency leads to higher stress amplitude ratio, but when the frequency becomes fast up to a certain point, the stress amplitude ratio will reach its maximum limit and the frequency dependence becomes insignificant. And also, the result of undrained cyclic triaxial deformation test shows a fact that a faster loading frequency leads to higher equivalent shear modules and smaller hysteresis damping ratio, and confirms the frequency dependence of cohesive soil. Meanwhile, the result of the creep test shows that continuing creep is created in the undrained cyclic triaxial test with slow loading frequency rate, and since loading rate becomes slower at the vicinity of the maximum and the minimum deviator stress due to sine wave loading, the vicinity of the maximum and the minimum deviator stress shall be more influenced by creep.

• 한국해양공학회지
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• 제25권3호
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• pp.34-39
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• 2011

This study investigated the shear and CBR characteristics of dredge soil-bottom ash-waste tire powder-mixed lightweight soil, which was developed to recycle dredged soil, bottom ash, and waste tire powder. Test specimens were prepared with various contents of waste tire powder ranging from 0 to 100% at 50% intervals by the weight of the dry dredged soil. Several series of triaxial compression tests and CBR tests were conducted. The shear strength characteristics of the lightweight soil were compared using two different shear tests (triaxial compression test and direct shear test). The experimental results indicated that the internal friction angle of the lightweight soil obtained by the direct shear tests was greater than that by the triaxial shear tests. However, the cohesion value obtained by the triaxial shear tests was greater than that by the direct shear tests. The CBR value of the lightweight soil decreased from 35% to 15% as waste tire powder content increased.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.569-576
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• 2000

This study performs a series of Triaxial Compression Test for clay-sand composite specimens changing area replacement ratio. Purpose of the test is to conform the propriety of weighted average method in estimating shear strength of the composite ground. The test results show that measured values of shear strength of composite specimens are larger by 20∼30% than those from estimation using the current weighted average method. It is thought that the differences are from pseudo-overconsolidation behavior of composite specimens.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 연약지반처리위원회 학술세미나
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• pp.71-78
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• 2000

SHANSEP method involves the consolidation to stresses in excess of the preconsolidation pressure in order to overcome sample disturbance effect. The concept of SHANSEP is based on an approach to laboratory test which attempts to reproduce the in-situ conditions more closely than is possible in routine tests and evaluates normalized strength parameters for the soil as a function of OCR. But SHANSEP method can be applied only to fairly uniform clay deposits, and is unsuitable for a random deposit. In this study, CK/sub o/U triaxial compression test and incremental loading consolidation test were performed for the application of SHANSEP method on Yangsan clay. During the K/sub o/-consolidation, triaxial specimens were consolidated to stress equal to two times the in-situ vertical effective stress. And for overconsolidated condition, the specimens were swelled to a known vertical effective stress in order to have the desired OCR. With the results of CK/sub o/U triaxial compression test using the block samples, the relationship between c/sub u//σ/sub vc/' and OCR on Yangsan clay was established. For evaluating the undrained shear strength of Yangsan clay with depth, CK/sub o/U triaxial compression test was performed using the piston samples taken from Yangsan site. And also undrained shear strength was analyzed from the in-situ test such as Cone Penetration Test(CPT), Dilatometer Test(DMT), and Field Vane Test(FVT) and was compared with that of CK/sub o/U triaxial compression test.

• 한국지반공학회논문집
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• 제24권2호
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• pp.5-14
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• 2008

국내 석산에서 생산되는 골재를 사용하여 대형삼축시험과 대형직접전단시험을 동시에 수행한 후 전단특성을 비교하였다. 비교를 위하여 시험조건을 가능한 일치시켰으며, 상대밀도를 50%, 70%, 90%의 세 가지로 변화시켜 시험을 수행하였다. 시험결과 응력-변형률 거동은 두 가지 시험에서 동일하게 나타나며, 전단강도는 상대밀도의 크기에 따라 시험방법별로 추세가 달라진다. 즉, 낮은 상대밀도에서는 대형직접전단시험의 내부마찰각이 대형삼축압축시험 결과 값에 비하여 작게 나타나고, 높은 상대밀도에서는 이 현상이 역전됨을 확인하였다.

• 한국지반공학회논문집
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• 제22권10호
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• pp.151-163
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• 2006

본 논문에서는 모래의 비배수 정적전단거동과 반복전단거동의 상호관계를 분석하기 위하여 낙동강 모래를 사용하여 비배수 정적 및 반복삼축시험을 실시하였다. 정적삼축시험은 반복전단거동과의 상호비교를 위하여 인장시험을 포함하여 실시하였다. 그리고 반복삼축시험은 초기정적전단응력$(q_{st})$과 반복응력$(q_{cy})$조건을 조합하여 여러 응력조건 하에서 실시하였다. 시험결과 반복전단거동의 응력경로는 정적전단거동의 한계응력비(CSR)선을 지나면서 유동변형이 발생하여 정적전단거동과 일치하였으며, 그 후 정적전단거동의 파괴선(FL)을 따라 파괴가 발생하였다. 이러한 반복 전단거동의 응력경로는 시험방법이 다름에 따른 약간의 차이는 있으나 정적전단거동의 응력경로와 본질적으로 동일함을 알 수 있었다.

• 한국농공학회지
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• 제23권3호
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• pp.96-104
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• 1981

In order to investigate the characteristics of the shear strength of the unsaturated cohesive soils which has mean characters of sand and clay widely used for banking, I selected soil samples from An-sung district and, against it, performed direct shear test and unconfined compression test changing grain size, compaction energy and moisture content and also performed triaxial compression test under optimum moisture content. The results are as follows; 1.As the passing percent of the No. 200 sieve increased from 23.6% to 56.1%, cohesion increased from 0. 202kg/cm2 to 0. 398kg/cm2 under the direct shear test and from 0.38 kg/cm2 to 1. 05kg/cm2 under the tria4al compression test, internal friction angle decreased from 44. 78$^{\circ}$ to 34. 34$^{\circ}$ under the direct shear test and from 31. 88$^{\circ}$ to 13. 31$^{\circ}$ under the triaxial compression test. 2.Cohesion showed it's maximum value around OMC and internal friction angle showed a tendency to increase according to the decrease of water content but it's increasing ratio was relatively slow. 3.Decreasing ratio of cohesion and internal friction angle was relatively sensitive according to the decrease of compaction energy. 4.The smaller of the vertical stress and the coarser of the grain size of samples, changing of the volume showed a tendency to increase and as the increase of water content, the shear displacement (dh) at failure shear stress ($\tau$f) showed maximum and the $\tau$f-dh curve was gentle. 5.To synthesize the results of the direct shear test and the triaxial compression test, cohesion showed higher under the triaxial compression test and internal friction angle showed a tendeney to appear higher under the direct shear test. It seems that we can get correspondent results by removing the side friction of mold with soils and adjusting the vertical stress and shearing speed under the direct shear test.

• 한국지반환경공학회 논문집
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• 제10권1호
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• pp.25-34
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• 2009

댐이나 항만 건설시 재료로 사용되는 조립재는 입자크기가 일반 토사에 비해 매우 크기 때문에 이러한 재료에 대해서 전단시험을 수행할 때에는 가급적 대형 전단시험장치를 사용하는 것이 보다 정확한 결과를 얻기 위해 바람직하다. 대형 전단시험장치로는 일반적으로 대형 직접전단시험장치와 대형 삼축압축시험장치가 있으나 일반 토질시험장치와 비교해 제작과 보급, 운영 등의 어려움 때문에 현재까지 국내에서 두 시험장치를 사용하여 시험을 수행한 실적은 많지 않은 편이다. 본 연구에서는 댐 축조재로 사용되는 입경이 큰 조립재료를 대상으로 시료의 평균 입자크기와 공시체 크기, 연직응력(구속압) 조건 등에 차이가 있는 총 6개 case에 대해서 대형 직접전단시험과 대형 삼축압축시험을 수행하고 두 시험간 전단강도 특성의 차이를 비교하였다. Mohr-Coulomb 강도규준에 의한 전단강도를 기준으로, 대형 직접전단시험을 통해 산정된 전단강도가 대형 삼축압축시험을 통해 산정된 전단강도보다 전체적으로 크게 나타났으며 또한, 1,000kPa 수직응력에 대해 두 시험간 산정된 전단강도를 비교한 결과 대형 직접전단시험에 의한 전단강도가 대형 삼축압축시험에 의한 전단강도보다 약 10~70% 크게 나타나 입경이 작은 일반 토사와 비교해 그 차이가 크고, 대형 직접전단시험결과의 분산도가 상대적으로 높은 것으로 나타났다.

• 한국철도학회논문집
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• 제13권1호
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• pp.84-91
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• 2010

본 연구에서는 철도, 도로 등 대형 성토지반구조물의 주요 지반재료인 입경이 큰 조립재료에 대해 전단강도, 변형계수, 응력-변형 거동과 같은 지반공학적 설계정수를 평가 산정할 수 있는 대형삼축압축시험장비를 구축하고, 이를 활용한 도상자갈재료에 대한 정적삼축압축시험 결과를 통해 그 의미와 적용 가능성을 제시하였다. 도상자갈과 같이 지표면에 설치되어 포화 가능성이 낮고, 구속압이 작은 경우에는 진공압(vacuum)으로 구속압을 제어하는 방식이 효과적임을 확인할 수 있었다. 도상자갈 재료의 삼축압축시험 결과로부터 구속압별 전단강도, 변형계수, 입자파쇄 영향 등의 합리적인 결과와 경향을 확인하였으며, 모암의 입자강도, 구속압 등의 영향을 고려하여 전단강도 포락선을 예측할 수 있는 비선형식에 적합한 재료 상수를 산정, 적용하여 실험 결과를 근접하게 재현해낼 수 있었다.