• Title, Summary, Keyword: 동적콘관입시험

Search Result 36, Processing Time 0.049 seconds

Physical and Mechanical Characteristics of Subgrade Soil using Nondestructive and Penetration Tests (비파괴시험과 관입시험에 의한 노상토의 물리·역학적 특성)

  • Kim, Kyu-Sun;Kim, Dong-Hee;Fratta, Dante;Lee, Woojin
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.31 no.1C
    • /
    • pp.19-27
    • /
    • 2011
  • This paper evaluates the applicability of wave-based nondestructive methodologies and a penetration test for compaction quality measurements during road construction. To evaluate the physical and mechanical properties of compacted subgrade soil layers, soil stiffness gauge (SSG), time domain reflectometry (TDR), and miniature electro-mechanical systems (MEMS) accelerometers were used to nondestructively evaluate the soil response during and after compaction and dynamic cone penetrometer (DCP) profiles were used to evaluate the soil shear strength after compaction was completed. At the field site, two types of soils were compacted with four different compaction equipments and energies. Field testing results indicate that soil parameters evaluated by different testing methods, which are SSG, TDR, MEMS accelerometer, and DCP, are highly correlated. In addition, it is shown that the physical and mechanical tests deployed in this study can be used as alternative methods to the conventional compaction quality evaluation methods when assessing the overall quality and the engineering response of compacted lifts.

Fundamental Study on Establishing the Subgrade Compaction Control Criteria of DCPT with Laboratory Test and In-situ Tests (실내 및 현장실험를 통한 DCPT의 노상토 다짐관리기준 정립에 관한 기초연구)

  • Choi, Jun-Seong
    • International Journal of Highway Engineering
    • /
    • v.10 no.4
    • /
    • pp.103-116
    • /
    • 2008
  • In this study, in-situ testing method, Dynamic Cone Penetration Test(DCPT) was presented to establish a new compaction control criteria with using mechanical property like elastic modulus instead of unit weight for field compaction control. Soil chamber tests and in-situ tests were carried out to confirm DCPT tests can predict the designed elastic modulus after field compaction, and correlation analysis among the DCPT, CBR and resilient modulus of sub grade were performed. Also, DCPT test spacing criteria in the construction site was proposed from the literature review. In the result of laboratory tests, Livneh's equation was the best in correlation between PR of DCPT and CBR, George and Pradesh's equation was the best in the predicted resilient modulus. In the resilient modulus using FWD, Gudishala's equation estimates little larger than predicted resilient modulus and Chen's equation estimates little smaller. And KICT's equation estimates the modulus smaller than predicted resilient modulus. But using the results of laboratory resilient modulus tests considering the deviatoric and confining stress from the moving vehicle, the KICT's equation was the best. In the results of In-situ DCPT tests, the variation of PR can occur according to size distribution of penetrate points. So DCPT test spacing was proposed to reduce the difference of PR. Also it was shows that average PR was different according to subgrade materials although the subgrade was satisfied the degree of compaction. Especially large sized materials show smaller PR, and it is also found that field water contents have influence a lot of degree of compaction but a little on the average PR of the DCPT tests.

  • PDF

Determination of shear wave velocity profiles in soil deposit from seismic piezo-cone penetration test (탄성파 피에조콘 관입 시험을 통한 국내 퇴적 지반의 전단파 속도 결정)

  • Sun Chung Guk;Jung Gyungja;Jung Jong Hong;Kim Hong-Jong;Cho Sung-Min
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • /
    • pp.125-153
    • /
    • 2005
  • It has been widely known that the seismic piezo-cone penetration test (SCPTU) is one of the most useful techniques for investigating the geotechnical characteristics including dynamic soil properties. As the practical applications in Korea, SCPTU was carried out at two sites in Busan and four sites in Incheon, which are mainly composed of alluvial or marine soil deposits. From the SCPTU waveform data obtained from the testing sites, the first arrival times of shear waves were and the corresponding time differences with depth were determined using the cross-over method, and the shear wave velocity profiles (VS) were derived based on the refracted ray path method based on Snell's law and similar to the trend of cone tip resistance (qt) profiles. In Incheon area, the testing depths of SCPTU were deeper than those of conventional down-hole seismic tests. Moreover, for the application of the conventional CPTU to earthquake engineering practices, the correlations between VS and CPTU data were deduced based on the SCPTU results. For the empirical evaluation of VS for all soils together with clays and sands which are classified unambiguously in this study by the soil behavior type classification Index (IC), the authors suggested the VS-CPTU data correlations expressed as a function of four parameters, qt, fs, $\sigma$, v0 and Bq, determined by multiple statistical regression modeling. Despite the incompatible strain levels of the down-hole seismic test during SCPTU and the conventional CPTU, it is shown that the VS-CPTU data correlations for all soils clays and sands suggested in this study is applicable to the preliminary estimation of VS for the Korean deposits and is more reliable than the previous correlations proposed by other researchers.

  • PDF

A Study on the Relation between Dynamic Deflection Modulus and In-Situ CBR Using a Portable FWD (소형FWD를 이용한 노상토의 동적변형계수와 현장 CBR의 상관 연구)

  • Kang, Hee Bog;Kim, Kyo Jun;Park, Sung Kyoon;Kim, Jong Ryeol
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.12 no.2
    • /
    • pp.149-155
    • /
    • 2008
  • The road construction, as part of effort to ease the worsening traffic, has been underway throughout the nation, while the existing road has been increasingly losing its load carrying capacity due to such factors as heavy traffic and weathering. In the case of site, the soil type, plasticity index, and specific gravity were SC, 12.2%, and 2.66, respectively. The maximum dry density, optimum moisture content and modified CBR were $1.895g/cm^3$ (Modified Compaction D), 13.6%, and 16.2%, respectively. A correlation of coefficient expressed good interrelationship by 0.90 between the CBR estimated from a dynamic penetration index of dynamic cone penetrometer test and a deformation modulus converted from a dynamic deflection modulus obtained from a portable FWD test.

Geotechnical Characteristics of a Waste Lime Embankment (부산물석회 성토지반의 지반공학적 특성)

  • Hong, Seung Seo;Kim, YoungSeok;Bae, Gu-Jin
    • The Journal of Engineering Geology
    • /
    • v.25 no.4
    • /
    • pp.547-555
    • /
    • 2015
  • This work investigated the geotechnical characteristics of an embankment constructed with a mixture of soil and waste lime. The waste lime was a by-product of the manufacture of Na2CO3 at a near by chemical factory in Incheon. Field measurements were take three years after construction, and included geotechnical tests such as field density measurement, plate loading testing, dynamic cone penetration testing, and field CBR measurement. The results indicate that the geotechnical characteristics of waste lime mixtures are suitable for embankment works.

Soil Stiffness Evaluation using Vibration Frequency (진동주파수 해석을 통한 지반강성 평가방법)

  • Kim, Ju-Hyong;Yoo, Wan-Kyu;Kim, Byoung-Il
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.987-992
    • /
    • 2009
  • Continuous Compaction Control is a new cutting edge technique in United States, Japan and European construction market that uses an instrumented compactor to measure soil stiffness in real time usually with vehicle tracking system such as Global Navigation Satellite System (GNSS). In this study, soil stiffness was evaluated by adapting Fourier transforming technique with acceleration data obtained from accelerometers used as a continuous compaction control instrument. The soil stiffness obtained by accelerometers gave analogous results with reference results such as dry density, elastic modulus obtained from Geogauge and Light falling deflectometer.

  • PDF

Synthetic Application of Seismic Piezo-cone Penetration Test for Evaluating Shear Wave Velocity in Korean Soil Deposits (국내 퇴적 지반의 전단파 속도 평가를 위한 탄성파 피에조콘 관입 시험의 종합적 활용)

  • Sun, Chang-Guk;Kim, Hong-Jong;Jung, Jong-Hong;Jung, Gyung-Ja
    • Geophysics and Geophysical Exploration
    • /
    • v.9 no.3
    • /
    • pp.207-224
    • /
    • 2006
  • It has been widely known that the seismic piezo-cone penetration test (SCPTu) is one of the most useful techniques for investigating the geotechnical characteristics such as static and dynamic soil properties. As practical applications in Korea, SCPTu was carried out at two sites in Busan and four sites in Incheon, which are mainly composed of alluvial or marine soil deposits. From the SCPTu waveform data obtained from the testing sites, the first arrival times of shear waves and the corresponding time differences with depth were determined using the cross-over method, and the shear wave velocity $(V_S)$ profiles with depth were derived based on the refracted ray path method based on Snell's law. Comparing the determined $V_S$ profile with the cone tip resistance $(q_t)$ profile, both trends of profiles with depth were similar. For the application of the conventional CPTu to earthquake engineering practices, the correlations between $V_S$ and CPTu data were deduced based on the SCPTu results. For the empirical evaluation of $V_S$ for all soils together with clays and sands which are classified unambiguously in this study by the soil behavior type classification index $(I_C)$, the authors suggested the $V_S-CPTu$ data correlations expressed as a function of four parameters, $q_t,\;f_s,\;\sigma'_{v0}$ and $B_q$, determined by multiple statistical regression modeling. Despite the incompatible strain levels of the downhole seismic test during SCPTu and the conventional CPTu, it is shown that the $V_S-CPTu$ data correlations for all soils, clays and sands suggested in this study is applicable to the preliminary estimation of $V_S$ for the soil deposits at a part in Korea and is more reliable than the previous correlations proposed by other researchers.

Liquid and Plastic Limits of Cohesive Soil by Static and Dynamic Test Methods and Testers (정적 및 동적시험법과 실험자에 따른 점토의 액·소성한계)

  • Kim, Chan-Kee;Yeo, Jin-Soo;Moon, Young-Seog;Park, Hyung-Yeol;Kim, Tae-Hyung
    • Journal of the Korean Geotechnical Society
    • /
    • v.33 no.3
    • /
    • pp.5-15
    • /
    • 2017
  • In this study, the liquid and plastic limit tests were conducted on Paju clay with Casagarande method (dynamic) and the fall cone test method (static) to find out the effects of test methods and testers on their values. Six testers, who already have the experience of test, participated. As a results of liquid limit tests, the fall cone test method showed 4% smaller liquid limit compared to the value determined by Casagrande method. As the number of tests increased, the fall cone test method showed less variation between testers and the variation range of level of proficiency was also more stable. In the case of one point method, the liquid limit determined by the fall cone test method varied with smaller range compared to the Casagrande. Consequently, the fall cone test provided more stable liquid limit value than that of Casagrande method. For the results of plastic limit tests, there were no difference between Casagrande method and the fall cone test unlike liquid limit test results. In other words, both methods showed that plastic limit reached the average value as the number of tests increased, and the tendency level of proficiency also showed to get better.

Application of the New Degree of Compaction Evaluation Method (새로운 다짐도 평가기법의 적용성에 관한 연구)

  • Park, Keun-Bo;Kim, Ju-Hyong
    • Journal of the Korean Geotechnical Society
    • /
    • v.28 no.2
    • /
    • pp.5-14
    • /
    • 2012
  • CMV(Compaction Meter Value) obtained from compaction results using an accelerometer, which measures the impact on the ground and the resilient force of the ground, is compared with the other degree of compaction through regression analysis. As a result, there is no correlation between results from conventional test methods (e.g., the plate load test and field density test) and the degree of compaction evaluated by either the Geogauge or the dyanamic cone penetrometer. To assess the possibility of replacing the conventional test methods with new test methods using CMV, several degrees of compaction tests were carried out. Those results show that the CMV obtained from compaction results using an accelerometer can be used as a substitute for conventional methods to evaluate the stiffness characteristics of compacted soil.

Estimating Soil Thickness in a Debris Flow using Elastic Wave Velocity (탄성파 속도를 활용한 토석류 위험지역의 표토층 두께 결정)

  • Min, Dae-Hong;Park, Chung-Hwa;Lee, Jong-Sub;Yoon, Hyung-Koo
    • The Journal of Engineering Geology
    • /
    • v.26 no.1
    • /
    • pp.143-152
    • /
    • 2016
  • To estimate the stability of a debris flow it is necessary to know the mass of surface soil, cohesion, slope, and friction angle. Given that the mass of surface soil is a function of soil thickness and mass density, it is important to obtain reliable estimates of soil thickness across a wide area. The objective of this paper is to estimate soil thickness using the elastic wave velocity with a new standard velocity. Tests are performed in debris-flow hazard areas, after which four profiles are selected to obtain the elastic wave velocity. Dynamic cone penetration tests are carried out to find the soil thickness at 18 points. The elastic wave velocity shows the area consists of 3~4 layers, and soil thicknesses are predicted by utilizing the new standard. The elastic wave velocity and dynamic cone penetration tests yield large differences in soil thickness. Therefore, this study shows that the new standard is useful not only in estimating soil thickness but also in improving the reliability of estimates of soil thickness.