• Title/Summary/Keyword: Dynamic cone penetration

Search Result 60, Processing Time 0.031 seconds

Study of Application for Using Nondestructive Method in Gravel Area (사석 성토 지역의 비파괴 조사 기법 적용성 연구)

  • Yoon, Hyung-Koo
    • Journal of the Korean Geotechnical Society
    • /
    • v.39 no.7
    • /
    • pp.49-56
    • /
    • 2023
  • Gravel is commonly employed to enhance the bearing capacity of foundations and provide stable support for structures. However, effectively assessing the ground characteristics in the presence of gravel poses significant challenges. This study aims to compare the resolution of ground containing gravel using electrical resistivity, elastic wave surveys, and ground penetration radar (GPR). Nondestructive methods are applied at construction sites where soil improvement is carried out using gravel. The experiments focus on shallow depths, and the obtained results cover depths up to 2 m. Both the electrical resistivity and elastic wave techniques exhibit similar behavior in their findings, indicating comparable outcomes. However, GPR has limitations in observing the characteristics of ground with gravel. Dynamic cone-penetration tests were conducted to validate these findings. The electrical resistivity and elastic wave profiles exhibited similar behaviors in localized areas, further supporting their compatibility and reliability.

Correlation Analysis between DCPT Value and SPT Value (동적콘관입시험값과 표준관입시험값의 상관성 분석)

  • Lee, Bongjik;Lee, Jongkyu
    • Journal of the Korean GEO-environmental Society
    • /
    • v.15 no.8
    • /
    • pp.23-30
    • /
    • 2014
  • In-situ penetration tests have been widely used in geotechnical engineering for site investigation in support of analysis and design. Standard Penetration Test (SPT) and Dynamic Cone Penetration Test (DCPT) are typical dynamic sounding. DCPT was originally developed as an alternative for evaluating the properties of subgrade soils. The main advantages of DCPT are that it is fast, inexpensive, and it is particularly useful in delineating areas of weak soils overlying stronger strata and in quickly assessing the variability of the soil conditions. But lack of standardization is main reason that this test method has not been advanced more in recent years. In this study, it is clarified the correlation with the SPT blow count, N from DCPT data using big DCP eqipment. Regression analysis and correlationship analysis were conducted with the data from relationship between SPT and DCPT. The analysis results showed that the convert fact are in the range of 1.12~1.31 with variation with soil property.

A Mechanical Properties According to the Compaction Degree on Weathered Granite Soil Using Lightweight Dynamic Cone Penetrometer (경량 동적콘관입시험기를 이용한 화강풍화토의 다짐도에 따른 역학특성)

  • Kim, Yeon-Il;Kim, Jin-Young;Shim, Jae-Rok;Choi, Jin;Kang, Kwon-Soo;Baek, Won-Jin;Lee, Kang-Il
    • Journal of the Korean Geosynthetics Society
    • /
    • v.13 no.3
    • /
    • pp.21-30
    • /
    • 2014
  • In this study, the applicability of the lightweight dynamic cone penetrometer in the domestic slope site was investigated using the weathered granite soil sampled form the Namwon slope site. And then, the lightweight dynamic cone penetration tests according to the change in the degree of compaction and water content were performed and it was analyzed with the correlations between the degree of compaction, the void ratio, the degree of saturation and the value of cone resistance. From the laboratory test results, the cone penetration resistance was rapidly increased in the dry side of the optimum moisture content, and it was largely decreased in the wet side of the optimum moisture content. Moreover, when the degree of compaction and the degree of saturation are large, the cone resistance is increased linearly. And a high correlativity was shown between water content, void ratio, the degree of saturation and the cone resistance. From these results, it is judged that the lightweight dynamic cone penetrometer can be applied to the investigation on the site slope.

Prediction of End Bearing Capacity for Pre-Bored Steel Pipe Piles Using Instrumented Spt Rods (SPT 에너지효율 측정 롯드를 이용한 매입말뚝의 선단지지력 예측)

  • Nam, Moon S.;Park, Young-Ho;Park, Yong-Seok
    • Journal of the Korean Geotechnical Society
    • /
    • v.29 no.12
    • /
    • pp.105-111
    • /
    • 2013
  • The standard penetration test (SPT) has been widely used because of its usability, economy, and many correlations with soil properties among other factors. In SPT, hammer energy is an important factor to evaluate and calibrate N values. To measure hammer energy, an instrumented SPT rod was developed considering that stress waves transferring on rods during SPT driving are the same as stress waves transferring on piles due to pile driving. Using this idea, an instrumented SPT rod with a pile driving analyzer was applied as a pile capacity prediction tool in this study. In order to evaluate this method, SPT and dynamic cone tests with the instrumented SPT rod were conducted and also 2 pile load tests were performed on pre-bored steel pipe piles at the same test site. End bearings were predicted by CAPWAP analysis on force and velocity waves from dynamic cone penetration tests and SPT. Comparing these predicted end bearings with static pile load tests, a new prediction method of the end bearing capacity using the instrumented SPT rod was proposed.

Rod effects on transferred energy into SPT sampler using smart measurement system

  • Park, Geunwoo;Kim, Namsun;Hong, Won-Taek;Lee, Jong-Sub
    • Smart Structures and Systems
    • /
    • v.30 no.2
    • /
    • pp.159-172
    • /
    • 2022
  • To improve the accuracy of the standard penetration test (SPT) results, smart measurement system, which considers the energy transfer ratio into the sampler (ETRSampler), is required. The objective of this study is to evaluate the effects of joints and rod length on the transferred energy into the sampler. The energy transfer ratios into the rod head (ETRHead) and ETRSampler, and the energy ratio from the head to the sampler (ERHS) were obtained using energy modules, which were installed at the rod head and above the SPT sampler. Linear regression analyses are conducted to correlate the ERHS with the number of joints, rod length, and SPT N-values. In addition, the dynamic resistances are calculated using both transferred energies into the rod head and into the sampler, and are compared with the corrected cone tip resistance measured from the cone penetration test (CPT). While the ETRHead are generally constant, but the ETRSampler and ERHS gradually decrease along the depth or the number of joints, except at certain depths with high SPT N-values. Thus, the ERHS can be estimated using the number of joints, rod length, and SPT N-values. The dynamic resistance evaluated by ESampler produces a better correlation with the corrected cone tip resistance than that by EHead. This study suggests that transferred energy into the SPT sampler may be effectively used for more accurate subsurface characterization.

Design of a piezovibrocone and calibration chamber

  • Samui, Pijush;Sitharam, T.G.
    • Geomechanics and Engineering
    • /
    • v.2 no.3
    • /
    • pp.177-190
    • /
    • 2010
  • This paper presents the details of indigenous development of the piezovibrocone and calibration chamber. The developed cone has a cylindrical friction sleeve of $150cm^2$ surface area, capped with a $60^{\circ}$ apex angle conical tip of $15cm^2$ cross sectional area. It has a hydraulic shaker, coupled to the cone penetrometer with a linear displacement unit. The hydraulic shaker can produce cyclic load in different types of wave forms (sine, Hover sine, triangular, rectangular and external wave) at a range of frequency 1-10 Hz with maximum amplitude of 10 cm. The piezovibrocone can be driven at the standard rate of 2 cm/sec using a loading unit of 10 ton capacity. The calibration chamber is of size $2m{\times}2m{\times}2m$. The sides of the chamber and the top as well as the bottom portions are rigid. It has a provision to apply confining pressure (to a maximum value of $4kg/cm^2$) through the flexible rubber membrane inlined with the side walls of the calibration chamber. The preliminary static as well as dynamic cone penetration tests have been done sand in the calibration chamber. From the experimental results, an attempt has been made to classify the soil based on friction ratio ($f_R$) and the cone tip resistance ($q_c$).

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.

A Study on Numerical Modeling of Dynamic CPT using Particle Flow Code (입자결합모델을 이용한 동적콘관입시험(DCPT)의 수치해석 모델링에 관한 연구)

  • You, Kwang Ho;Lee, Chang Su;Choi, Jun Seong
    • International Journal of Highway Engineering
    • /
    • v.16 no.2
    • /
    • pp.43-52
    • /
    • 2014
  • PURPOSES : To solve problems in current compaction control DCPT(Dynamic Cone Penetrometer Test), highly correlated with various testing methods, simple, and economic is being applied. However, it、s hard to utilize DCPT results due to the few numerical analyses for DCPT have been performed and the lack of data accumulation. Therefore, this study tried to verify the validation of numerical modeling for DCPT by comparing and analyzing the results of numerical analyses with field tests. METHODS: The ground elastic modulus and PR(Penetration Rate) value were estimated by using PFC(Particle Flow Code) 3D program based on the discrete element method. Those values were compared and analyzed with the result of field tests. Also, back analysis was conducted to describe ground elastic modulus of field tests. RESULTS : Relative errors of PR value between the numerical analyses and field tests were calculated to be comparatively low. Also, the relationship between elastic modulus and PR value turned out to be similar. CONCLUSIONS : Numerical modeling of DCPT is considered to be suitable for describing field tests by carrying out numerical analysis using PFC 3D program.

Analysis of load-settlement behaviour of shallow foundations in saturated clays based on CPT and DPT tests

  • Mir, Mouna;Bouafia, Ali;Rahmani, Khaled;Aouali, Nawel
    • Geomechanics and Engineering
    • /
    • v.13 no.1
    • /
    • pp.119-139
    • /
    • 2017
  • Static Penetration Test (CPT) and Dynamic Penetration Test (DPT) are commonly used in-situ tests in a routine geotechnical investigation. Besides their use for qualitative investigation (lithology, homogeneity and spatial variability), they are used as practical tools of geotechnical characterization (resistance to the penetration, soil rigidity) and modern foundation design as well. The paper aims at presenting the results of an extensive research work on the evaluation of the 1D primary consolidation settlement of saturated clayey soils on the basis of the CPT or DPT tests. The work is based on an analysis of the correlations between the tip resistance to penetration measured in these tests and the parameters of compressibility measured by the compressibility oedometer test, through a local geotechnical database in the northern Algeria. Such an analysis led to the proposal of two methods of calculation of the settlement, one based on the CPT test and the other one on the DPT. The comparison between the predicted settlements and those computed on the basis of the oedometer test showed a good agreement which demonstrate the possbility to use the CPT and DPT tests as reliable tools of computation of foundation settlements in clayey soils.

Bearing Capacity of Pavement Foundation by Waste Lime Material using the Dynamic Cone Pentrometer (동적 콘관입시험기를 이용한 폐석회 혼합 도로노반 성토체의 현장 지지력 평가)

  • Kim, Young-Seok;Hong, Seung-Seo;Bae, Gyu-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.12 no.2
    • /
    • pp.927-935
    • /
    • 2011
  • In-situ California Bearing Ratio(CBR) test has been widely used for evaluating the subgrade condition in pavements. However, because the in-situ CBR test is expensive and takes time for operation, it is difficult to figure out the in-situ characteristics of subgrade strength in detail. For faster and economical operation, the Dynamic Cone Penetrometer(DCP) has been often utilized for estimating the subgrade strength in the field. The purpose of this paper is to determine the relationship between CBR value and DCP index of the embankment constructed with mixtures of soil and waste lime. Waste lime used in this study is producted as a by-product in the manufacturing process of making $Na_2CO_3$ from local chemical factory in Incheon. In this field measurement, the geotechnical tests such as field water content, field density, field CBR test, and dynamic cone penetration test were conducted.