• Title/Summary/Keyword: pressuremeter

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Analytical solution for undrained plane strain expansion of a cylindrical cavity in modified cam clay

  • Silvestri, Vincenzo;Abou-Samra, Ghassan
    • Geomechanics and Engineering
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    • v.4 no.1
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    • pp.19-37
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    • 2012
  • This paper presents the results of analytical and numerical analyses of the effects of performing a pressuremeter test or driving a pile in clay. The geometry of the problem has been simplified by the assumptions of plane strain and axial symmetry. Pressuremeter testing or installation of driven piles has been modelled as an undrained expansion of a cylindrical cavity. Stresses, pore water pressures, and deformations are found by assuming that the clay behaves like normally consolidated modified Cam clay. Closed-form solutions are obtained which allow the determination of the principal effective stresses and the strains around the cavity. The analysis which indicates that the intermediate principal stress at critical state is not equal to the mean of the other two principal stresses, except when the clay is initially isotropically consolidated, also permits finding the limit expansion and excess pore water pressures by means of the Almansi finite strain approach. Results are compared with published data which were determined using finite element and finite difference methods.

Analysis of Pile Head Lateral Load-Deflection Behavior of Steel-Concrete Composite Drilled Shafts (강관합성 현장타설말뚝 머리의 수평하중-변위 거동 분석)

  • Lee, Yong-An;Chung, Moon-Kyung;Park, Jae-Hyun;Lee, Ju-Hyung
    • Journal of the Korean Geotechnical Society
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    • v.27 no.12
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    • pp.97-106
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    • 2011
  • To analyze the lateral load-deflection behavior of steel-concrete composite drilled shafts, a series of lateral pile load tests were performed. The test results were compared with the results from various analytical methods for lateral pile behaviors using the coefficients of subgrade reaction ($k_h$) estimated by pressuremeter test (PMT) and standard penetration test (SPT). As a result, it was found that the analytical methods using the $k_h$ estimated by SPT N value were not suitable for evaluating the pile head lateral load-deflections of the piles within the allowable deflection. However, the methods using the $k_h$ calculated from PMT were able to represent the initial lateral behavior at the head of the piles fairly well. Also, the method by the pressuremeter curve, which was applied directly to the p-y curve of the piles, offered a reasonable lateral behavior estimation by applying the correction factor to the pile materials.

Measurement of Small-Strain Shear Modulus Using Pressuremeter Test (공내재하시험기를 이용한 미소변형 전단탄성계수 측정)

  • Kim, Dong-Su;Park, Jae-Yeong;Lee, Won-Taek
    • Geotechnical Engineering
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    • v.13 no.4
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    • pp.109-120
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    • 1997
  • In the working stress conditions, the strain level in a soil mass experienced by existing structures and during construction is less than about 0.1-1%. In order to analyse the deformational behavior accurately, the in-situ testing technique which provides the reliable deformational characteristics at small strains, needs to be developed. The purpose of this paper is to measure the small-strain shear modulus of soils by using pressuremeter test(PMT). PMT is a unique method for assessing directly the in-situ shear modulus of soils with strain amplitude. For the accurate small strain measurements without initial disturbance effect, the unloading-reloading cycle was used and the measured modulus was corrected in view of the relevant stress and strain levels around the PMT probe during testing. Not only in the calibration chamber but in the field, PMT tests were performed on the cohesionless soils. The variation in shear modulus with strain amplitude ranging from 10-2% to 0.5% was reliably determined by PMT PMT results were also compared with other in-situ and laboratory test results. Moduli obtained from different testing techniques matched very well if the effect of strain amplitude was considered in the com pall son.

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The Correlation Between RMR and Deformation Modulus by Rock masses using Pressuremeter (공내재하시험을 이용한 암종별 변형계수와 RMR의 상관성)

  • Ahn, Taebong
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.1
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    • pp.5-12
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    • 2011
  • In this study, correlation between measured deformation modulus using pressuremeter and RMR value conducted in 10 sites is analyzed, and applicability of the conventional empirical formulas to the rock masses in Korea are analyzed, It is found that if RMR is below 40, the correlation between deformation modulus and RMR accords Kim Gyo-won's formula and Aydan, Serafim and Pereira's one well, but if the RMR exceeds 40, the correlation was lower than those from the formula. Such results may be attribute to the fact that during classification of RMR, scores are weighed relatively more in joint conditions and apertures than such highly correlational items as uniaxial compression strength or RQD, and RMR would not be evaluated qualitatively due to different weathering degrees and rock mass types as well as engineers' personal errors. Sandstone among sedimentary rocks are quite well accord with suggested equation, but correlation of other rocks are due to large variance. In this study, correlation expressions of various rocks are proposed as the function of exponential based on the field test data.

Comparative Study About The Indirect Blood Pressure (measured by different Instruments and Methods) (측정도구와 방법에 따른 간접혈압측정치의 비교연구)

  • Suh Gil-Hee
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.1 no.1
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    • pp.51-68
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    • 1994
  • One aim of this study was to find out the difference of indirect blood pressure between the types of instruments. The difference of indirect blood pressure was measured with mercury sphygomomanometer and electronic blood pressuremeter. Another was to determine the difference of indirect blood pressure according to width of cuff and site of cuff. Indirect blood pressures were measured with the diaphragmatic side of sphygomomanometer. The subjects were 40 female volunteers, whose arm circumferences were from 22 to 34cm. The data were analyzed by SPSS-PC program and pared t-test was used. The results are summarized as follows ; 1. Mercury sphygomomanometer systolic pressure was higher(average 2.20mmhg) than electronic blood pressuremeter. It was statistically significant(p=0.026). 2. The value of Mercury sphygomomanometer diastolic pressure was lower(2.00mmhg) than electronic's. It was statistically significant(p=0.03) 3. In the mercury sphygomomanometer systolic pressure, the value of standard cuff($12{\times}23cm$) was higher(2.40mmhg) than large one's($14{\times}45cm$). It was statistically significant(p=0.007). 4. In diastolic pressure(K4), the value of standard cuff was higher(0.65mmhg) than large cuff's. It was not statistically significant(p=0.481). In K5, the value of standard cuff($12{\times}23cm$) was higher(0.55mmhg) than large cuff's. It was not statistically significant(p=0.541). 5. Difference according to site of showed that the values of systolic pressure over elbow joint were higher(20.00mmhg, 26.45mmhg) than ones at site of elbow joint. It was significant statistically(p=0.000) and clinically. 6. The values of diastolic pressure(K4) over elbow joint were higher(17.10mmhg, 21.60mmhg) than ones at site of elbow joint. It was significant statistically (p=0.000) and clinically. The values of K5 over elbow joint were higher(17.25mmhg, 22.15mmhg) than ones at site of elbow joint. It was significant statistically(p=0.000) and clinically. I think similar studies about indirect blood pressure according to diseases and positions are necessary. In addition, similar studies, are required about accuracy of method electronic blood pressuremeter according to site of mesurement.

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Long term earth pressure behavior behind stub abutment (난쟁이 교대배면의 장기 토압거동)

  • 박영호;정경자;김낙영;황영철
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.779-786
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    • 2002
  • To find a long term horizontal movement of superstructure caused by seasonal thermal change, several types of gages are installed such as soil earth pressuremeter behind stub abutment and jointmeter between approach slab and relief slab. As results, maximum passive earth pressure behind integral bridge abutments centerline with lateral movement of superstructure is about 1/6 of classic Rankine's earth pressure. And its distribution is not triangular but rectangular shape due to shape behind integral bridge abutments.

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Bearing Capacity and Settlement Characteristics of Weathered Granite Masses in Gyeonggi Area (경기지역 화강 풍화암반의 지지력 및 침하특성에 관한 연구)

  • Kim, Dong-Eun;Huh, Kyung-Han
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.4 s.19
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    • pp.37-47
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    • 2005
  • The purpose of this study is to estimate the bearing capacity and settlement characteristics of the weathered granite masses, and on the process to achieve the purpose, in the first place, the weathered degree according to the absorption index was examined and reviewed, then plate bearings test in in-situ depth were tested, and finally the result was compared and examined with the result of the existing, estimate method and pressuremeter test. In order to achieve the purpose of this study, a typical area distributed with weathered granite masses, gyeonggi area, was chosen as a sample site for testing, and in the result, it appeared and found out that the more the weathered degree increases when the plate bearing test are tested, the more the bearing capacity decreases a numerical indexes and the more greatly the width of the decrease of bearing capacity increases around the boundary of specific, weathered degrees. Also, In the result from estimating the bearing capacity of weathered granite masses by the existing, suggested formula, it appeared that there is a tendency that the more the weathered degree increases, the more similar the bearing capacity becomes with the result of plate bearing tests.

Evaluation for Marine Ground in Pusan Area using PMT (공내재하시험을 이용한 부산지역 해저지반의 평가)

  • 김동철;최용규
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.338-345
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    • 2000
  • In this study, applicability of PMT in domestic area and test procedure were studied. At six test holes of three construction sites in Pusan, PMT using Elastometer-200 type was done. The problems during test were investigated and the test results were analysed. Limit pressure, p$\sub$ι/ could be determined by p- Δv/v method. Using PMT results, marine soil in Pusan could be classified approximately. Net limit pressure value was in the range of 6.4 ∼ 22.5 kg/$\textrm{cm}^2$ in clay, 2.2 ∼ 30.0 kg/$\textrm{cm}^2$ in sand, 13.0 ∼ 58.0 kg/$\textrm{cm}^2$ in weathered soil and 47.0 ∼ 190.0 kg/$\textrm{cm}^2$ in weathered rock. Also, E$\sub$m//p$\sub$ι/ value was in the range of 2.4 ∼ 7.0 in clay, 2.6 ∼ 12.1 in sand, 6.8 ∼ 17.1 in weathered soil and 7.2 ∼ 29.6 in weathered rock.

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