• 제목/요약/키워드: Consolidation pressure

검색결과 464건 처리시간 0.027초

압밀특성에 관한 연구 (I) (선행하중이 압밀특성에 주는 영향) (A Study on the Characteristics of Consolidation of Soils (I) (The Influence of Pre-consolidation Load of Soils on Consolidation Characteristics))

  • 류능환;강예묵
    • 한국농공학회지
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    • 제18권4호
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    • pp.4242-4250
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    • 1976
  • The determination of the pre-consolidation load known to have a great effect on the consolidation characteristics of the soil have been researched and discussed in detail by many other researchers. A study was undertaken to investigate and compare the effect of pre-consolidation loads on the coefficient of permeability and the consolidation characterisics of soil through the consolidation test on the three types of soil samples. The results of this study are follows; 1. Large compression index is dependent on initial void ratio of the sample being used and the pressure-void ratio curve shows a curved linear relationship in over-consolidated area but a linear relationship in normally consolidated area.2. Settlement-time curve is S-shaped where the pressure is larger than pre-consolidation load and regardless of over-burden pressure, it is a similar straight line respectively in the secondary consolidation area. 3. Primary consolidation ratio of the sample increases almost linearly with the increase of over-burden pressure but the coefficient of volume compressibility decreases linearly with the increase of it. 4. Time factor of a certain degree of consolidation increases with over-burden pressure but the coefficient of consolidation decreases with it in over-consolidated area. There is a linear relationship between them in normally consolidated area. 5. The void ratio of completion point of primary consolidation decreases linearly with over-burden pressure. 6. The coefficient of permeability of sample decreases linearly with over-burden pressure in normally consolidated area, also it increases linearly with increment of the void ratio of the sample.

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침하량과 과잉간극수압을 이용한 압밀도의 추정 (Estimation of the Degree of Consolidation using Settlement and Excess Pore Water Pressure)

  • 이달원;임성훈
    • 한국농공학회지
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    • 제44권3호
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    • pp.111-121
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    • 2002
  • This study was performed to estimate the degree of consolidation using excess pore water pressure in the very soft ground. The final settlement prediction methods by Hyperbolic, Asaoka and Curve fitting methods from the measured settlement data were used to compare with the degree of consolidation estimated by excess pore water pressure. The dissipated excess pore water pressure during embankment construction and the peak excess pore water pressure on the completed embankment were used for the estimation of the degree of consolidation. After completion of embankment, it was concluded that the degree of consolidation estimated from dissipated excess pore water pressure was more reliable than that from the peak excess pore water pressure. And, the degree of consolidation estimated from the surface settlement was nearly the same as settlement of each layer. The degree of consolidation estimated from dissipated excess pore water pressure was a little larger than that from settlement.

일정 압력비 압밀시험을 이용한 연약점토의 압밀특성 분석 (Analysis of Consolidation Characteristics of Soft Clay Based on Constant Pressure Ratio Consolidation Test)

  • 김훈규;정두회
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 봄 학술발표회 논문집
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    • pp.455-462
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    • 2002
  • There exist several kinds of continuous consolidation tests to analyze the consolidation behavior of soft clay. The constant rate of strain (CRS) test has been adopted as a standard method by several countries, and some researches also have been peformed by domestic researchers. Among those, the constant pressure ratio (CPR) test is peformed with the constant ratio of excess porewater pressure to vertical effective stress. The test has the advantage of considerable reduction of duration time. In the study, the consolidation characteristics are analyzed by performing the CPR test as validate the pressure ratio with undisturbed soft clay and remolded clay, Also, results of the standard consolidation test and CRS test are compared to verify the CPR test can be employed for practical use. As a result, effects of variation of the pressure ratio on consolidation parameter are similar to the strain rate in the CRS test. Therefore, the test can be used to analyze the consolidation behavior of soft clay But the test have some problems such as expensive cost of equipment and highly skilled workmanship.

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수평배수재를 이용한 진공압밀공법의 해석에 관한 연구 (A Study on the Analysis of Vacuum Consolidation with Horizontal Drains)

  • 김홍택;김석열;윤창진;강인규;김창겸
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 봄 학술발표회 논문집
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    • pp.520-527
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    • 2000
  • In the present study, the analytical approaches of vacuum consolidation with horizontal drains were proposed, For dissipating rapidly pore-water in hydraulic fills, vacuum consolidation method applied vacuum pressure in horizontal drains is developed. In the analytical approaches, the governing equation is based on two-dimensional finite strain consolidation theory and the boundary conditions of horizontal drains are considered in applying negative pore-water pressure occurred by vacuum pressure, Also, parametric studies to vacuum pressure and installation pattern of horizontal drains are carried out.

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일축압축강도에 의한 선행압밀응력 예측 및 분석 (Prediction and Analysis of Pre-Consolidation by Unconfined Compressive Strength)

  • 송창섭;김명환
    • 한국농공학회논문집
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    • 제58권6호
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    • pp.71-77
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    • 2016
  • This study was to evaluate the feasibility of pre-consolidation pressure distribution characteristic of western and southern coastal region, using correlation of unconfined compressive strength and preceding research equation. Pre-consolidation of western and southern region showed similar trends undrained shear strength and pre-consolidation pressure in proportion to unconfined compressive strength. Predicted results of U.S. NAVY. (1982) equation revealed a small error western 9.7 % and southern 0.4 %. Prediction correlation results of pre-consolidation using unconfined compressive strength revealed an error western 16.8 % and southern 0.7 %. It was reported that less than 20 percent of pre-consolidation pressure prediction result of Casagrande forecasting error. Estimates of pre-consolidation pressure are possible, before the standard consolidation test, because it was reported that less than 20 % of the forecasting errors of Casagrande.

침하량과 간극수압에 의한 압밀도의 평가(지반공학) (Evaluation of the Degree of Consolidation using Settlement and Excessive Pore Water Pressure)

  • 이달원;임성훈;윤제식;김지문
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2000년도 학술발표회 발표논문집
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    • pp.444-450
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    • 2000
  • This study was performed to analyze the degree of consolidation by the dissipation of excessive pore water pressure and final settlement prediction methods of the very soft clay. Hyperbolic method, Asaoka method and curve fitting method were used to compute the degree of consolidation. The degree of consolidation with excessive pore water pressure were used to compute, which considered the dissipation time with embankment construction. The degree of consolidation that was obtained by the peak excessive pore water pressure was less than in the case of the dissipation excessive pore water pressure. And, the degree of consolidation by the total settlement was nearly the same value that of layer settlement. The degree of consolidation that was obtained by excessive pore water pressure was larger than in the case of the settlement.

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피압수압을 고려한 연직배수공법의 압밀해석 (Consolidation Analysis of Vertical Drain Considering Artesian Pressure)

  • 김상규;김호일;홍병만;김현태
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 1999년도 연약지반처리위원회 학술세미나
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    • pp.62-70
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    • 1999
  • Artesian pressure exists in Yangsan site, the maximum value of which has been measured as high as 5 t/m$^2$. This paper deals with the prediction of consolidation settlement for the site with artesian pressure. The consolidation settlement at the site has been accelerated using vertical band drains. Since the artesian pressure gives lower effective stress than a static condition, its effect should be considered in the settlement prediction. This case study shows that the prediction of settlement and pore pressure dissipation agrees well with the measurements, when considering the artesian effect.

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上部 構造와 下部 壓密地盤 間 상호작용 문제의 정식화에 대한 연구 (A Study on the Formulation of the Interaction Problem between Upper Structure and the Ground under Consolidation)

  • 이외득
    • 한국해양공학회지
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    • 제13권1호통권31호
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    • pp.51-61
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    • 1999
  • When a structure is built on the ground under consolidation, the instant corresponding contact pressure which the upper structure exerts on the ground is established. But, as the consolidation of the ground proceeds, the contact pressure is changed because of the flexural rigidity of the upper structure. This varied contact pressure exerts influence on the consolidation behavior of the ground. And, this varied consolidation behavior exerts on the contact pressure in retum. This kind of interaction between the upper struture and the olwer ground under consolidation contimues till all the consolidation process in finished. So this problem cannot be defined as a linear problem. In this paper an approximation method which can analyse this non-linear interaction problem is proposed by the FEM.

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이방압밀이 흙의 강도에 미치는 영향 (Effects of Anisotropic Consolidation on Strength of Soils)

  • 강병희
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 가을 학술발표회 논문집
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    • pp.3-14
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    • 2000
  • Anisotropic consolidation, shear, a transportational component during or after deposition each may produce anisotropic fabrics, which result in the anisotropic properties of soils. Nevertheless, the isotropically consolidated compression triaxial tests are commonly used in practice to determine the strength of the anisotropically consolidated soils because of their practicality and simplicity. In this paper the effects of anisotropic consolidation on the strength properties of soils are discussed. For the sandy soils consolidated under a constant vertical consolidation pressure, the deformation modulus decreases with decreasing consolidation pressure ratio($\sigma$$\sub$3c/'/$\sigma$ sub 1c/'), but the liquefaction resistance increases. For the saturated cohesive soils, both the undrained shear strength and undrained creep strength decrese with decreasing the consolidation pressure ratio. When the in-situ strength properties of the anisotropically and normally consolidated soils are determined by the isotropically consolidated tests, the undrained shear strength and creep strength of saturated cohesive soils as well as the deformation modulus of sandy soils are measured to be higher than the rear in-situ values. This, therefore, could lead to a dangerous judgement in stability analysis

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부산점토의 변형률 속도 의존적인 압밀특성 (Strain-rate-dependent consolidation characteristics of Busan clay)

  • 김윤태;조상찬;조기영
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.240-247
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    • 2005
  • In order to analyze effects of strain rate on consolidation characteristics on Busan clay, a series of constant rate of strain(CRS) consolidation tests with different strain rate and incremental loading test(ILT) were performed. From experimental test results, it was found that the preconsolidation pressure was dependent on the corresponding strain rate occurred during consolidation process. Also, consolidation curves normalized with respect to preconsolidation pressure gave a unique stress-strain curve. Coefficient of consolidation and permeability estimated from CRS test had a tendancy to converge to a certain value at normally consolidated range regardless of strain rate. An increase in excess pore pressure without change of total stress was noted on the incremental loading test after the end of loading.

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