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  • 鹿野 美弘, 櫻井 徹朗, 小松 健一, 山田 浩之, 斉藤 謙一
    Chemical and Pharmaceutical Bulletin
    1990年 38 巻 4 号 1082-1083
    発行日: 1990/04/25
    公開日: 2008/03/31
    ジャーナル フリー
    Two new polyacetylene compounds (
    4
    E
    ,
    6
    E
    , 12
    E
    )-1-acetoxy-3-isovaleryloxytetradeca-
    4
    ,
    6
    , 12-trien-
    8
    , 10-diyn-14-ol (
    B
    ), and (
    4
    E
    ,
    6
    E
    , 12
    E
    )-1-acetoxy-3-(
    2
    -methylbutyryloxy)tetradeca-
    4
    ,
    6
    , 12-trien-
    8
    , 10-diyn-14-ol (C) have been isolated along with (
    4
    E
    ,
    6
    E
    , 12
    E
    )-1-acetoxy-3-senecioyloxytetradeca-
    4
    ,
    6
    , 12-trien-
    8
    , 10-diyn-14-ol (A) from Atractylodes Rhizome (Karabyakujutu). The structures of these compounds were determined on the basis of their spectral data.
  • 黒川 美貴雄, 吉田 耕治, 永井 保嵩, 宇野 準
    Chemical and Pharmaceutical Bulletin
    1983年 31 巻 12 号 4312-4318
    発行日: 1983/12/25
    公開日: 2008/03/31
    ジャーナル フリー
    Two new partially saturated tricyclic ring systems,
    6
    ,
    6
    a,
    7
    ,
    8
    ,
    9
    , 10, 10a, 11-octahydro-11-oxodibenz [
    b
    ,
    e
    ] oxepins (3a and 3
    b
    ), and -thiepins (
    4
    a and
    4
    b
    ) were synthesized. Compounds
    4
    a and
    4
    b
    were desulfurized to give a pair of isomeric
    2
    -methylbenzoylcyclohexanes (10a and 10
    b
    ). Deuterated
    4
    a and
    4
    b
    (11a and 11
    b
    ) were prepared starting from butadiene-
    d6
    (12). The stereochemical features of 3a (trans), 3
    b
    (cis),
    4
    a (trans) and
    4
    b
    (cis) are compared with those of 10a, 10
    b
    , 11a and 11
    b
    on the basis of proton nuclear magnetic resonance data.
  • 澁谷 啓, 三田地 利之, 黄 聖春
    地盤工学会論文報告集
    2000年 40 巻 3 号 87-100
    発行日: 2000/06/15
    公開日: 2008/02/29
    ジャーナル フリー
    Natural sedimentary clays exhibit ageing effects on their behaviour when subjected to both consolidation and shearing. Attempts to characterising the in-situ 'structure'of soft marine clays have been made in case studies performed in Ariake (Japan) and in Bangkok (Thailand), each showing a typical profile of aged clay-structure with depth reflecting its site-specific geological consolidation history. In each site, profiles of Atterberg limits, natural water content, overconsolidation ratio (OCR), quasi-elastic shear modulus Gmax and the undrained shear strength cu with depth were attained from various laboratory tests, together with the a comparable profile of quasi-elastic shear modulus from insitu seismic survey Gf. Quantitative assessment of the aged clay-structure was made by using two different measures, metastability index MI (G) and the soil constant reflecting structure S (Jamiolkowski et al., 1994). The profiles of MI (G) and the S-value with depth were both determined based on the corresponding Gmax behaviour of the reconstituted sample. "Disturbance"of laboratory samples retrieved by using two different samplers (i.
    e
    ., Laval and Japanese thin-walled samplers) with two different sampling techniques (i.
    e
    ., pre-boring and displacement methods) was discussed. A new approach to estimate cu"in the ground", termed by the authors the MILK (Metastability Index coupled with Laboratory Ko test) method, is proposed. A trial of the MILK-method is demonstrated in soft Bangkok clay, the texture of which is similar to "soft cheese".
  • 黒川 美貴雄, 糸川 彰, 松本 純一, 福本 吉久, 月原 冨武
    Chemical and Pharmaceutical Bulletin
    1992年 40 巻 9 号 2270-2274
    発行日: 1992/09/25
    公開日: 2008/03/31
    ジャーナル フリー
    11-Amino-
    6
    ,
    6
    a,
    7
    ,
    8
    ,
    9
    , 10, 10a, 11-octahydrodibebenzo[
    b
    ,
    e
    ]thiepines (
    6
    a-
    d
    ) and -oxepines (
    7
    a-
    d
    ) were synthesized by the Leuckart reaction of
    6
    ,
    6
    a,
    7
    ,
    8
    ,
    9
    , 10, 10a, 11-octahydro-11-oxodibenzo[
    b
    ,
    e
    ]thiepines (1a,
    b
    )and -oxepines (
    2
    a,
    b
    ) followed by hydrolysis of the reaction products
    4
    a-
    d
    and 5a-
    d
    , respectively. The four diastereomers, cis(
    6
    a-H, 10a-H)-cis(10a-H, 11-H)
    6
    a and
    7
    a, cis(
    6
    a-H, 10a-H)-trans(10a-H, 11-H)
    6
    b
    and
    7
    b
    , trans(
    6
    a-H, 10a-H)-trans(10a-H, 11a-H)
    6
    c and
    7
    c, and trans(
    6
    a-H, 10a-H)-cis(10a-H, 11-H)
    6
    d
    and
    7
    d
    , were isolated and their configurations and conformations were elucidated by chemical methods together with 1H-nuclear magnetic resonance spectroscopic and X-ray crystallographic analyses.
  • 汪 発武, 佐々 恭二, 福岡 浩
    地盤工学会論文報告集
    2000年 40 巻 1 号 35-46
    発行日: 2000/02/15
    公開日: 2008/02/29
    ジャーナル フリー
    By employing an undrained cyclic loading ring-shear apparatus, a series of tests to reproduce the dynamic behavior of the Nikawa landslide induced by the January 17, 1995 Hyogoken-Nambu earthquake, is conducted. The test sample is Osaka-group coarse sandy soil taken from the landslide. The initial stress condition acting on a soil element in the sliding surface is applied to the sample. Based on the seismic records monitored at the JR Takarazuka Station, the input seismic wave is synthesized to reproduce the seismic stress acting on the sliding surface. The test results show that the soil failed due to the dynamic loading of the earthquake. The most important results are the excess pore water pressure generation and the acceleration of shear displacement continuing after the main shock. Combined with the grain crushing at the shear zone and the volume reduction in the drained constant-speed ring-shear test, the mechanism of this landslide is interpreted as, shear displacement causing grain crushing in the shear zone and volume reduction, and then resulting in a localized liquefaction phenomenon, "sliding-surface liquefaction". This geotechnical simulation test provides a reasonable interpretation of this highly mobile landslide.
  • OSAMU MATSUO
    地盤工学会論文報告集
    1996年 36 巻 Special 号 235-240
    発行日: 1996年
    公開日: 2012/08/13
    ジャーナル フリー
    Among the rivers damaged by the earthquake, two most severely damaged along the Yodo-gawa River are described. In the left levee, the settlement exceeded
    2
    m for a length of 1.
    4
    km, with a maximum settlement of 3 m. Sand boils were observed extensively on the ground surface near the damaged dikes. Holocene sandy soil with an SPT N-value of 10 or less existed in the upper part of the subsoil profile. These facts indicate that liquefaction of the soil was the major cause of the embankment damage. The cyclic stress ratio required to cause liquefaction was 0.30 as determined from cyclic triaxial tests on undisturbed samples.
  • 藤井 弘章, 国政 華菜, 難波 明代, 横溝 隆之, 西村 伸一, 島田 清, 堀 俊男, 西山 竜朗
    地盤工学会論文報告集
    2000年 40 巻 6 号 117-131
    発行日: 2000/12/15
    公開日: 2008/02/29
    ジャーナル フリー
    This study was performed to clarify which factors affected damage to tame-ike (small embankment dams for irrigation) in Hokudan Town as a result of the January 17, 1995 Hyogoken-Nambu earthquake. Factors were assumed to be : Location (
    e
    .g., Distance to Epicenter, etc.), Structure (
    e
    .g., Angle to Nearest Fault, Embankment Volume, etc.), Soil Properties of Embankment, Geology of Dam Site and History (Era of Construction, Repaired, etc.). Multivariate statistical analyses were performed for documentary data (damaged : 181, undamaged : 328). Ordinary statistical analyses were conducted for the data investigated in situ for soil properties of the embankment. The results show that the factors causing damage to dam are : (1) Nearest Fault (Nojima, Mizukoshi and
    D
    2
    ), (
    2
    ) Distance to Nearest Fault (less than 500 m), (3) Distance to Epicenter (approximately
    8
    to 14 km, which almost agrees with the location of seismic intensity
    7
    JMA), (
    4
    ) Elevation of Dam Site (higher than 100 m), (5) Embankment Volume (the greater the volume the more damage was caused), (
    6
    ) Direction of Dam Axis (normal or diagonal to the epicenter or to nearest the fault), (
    7
    ) Plan View of Dam Axis (3 or
    4
    axes), (
    8
    ) Surface Geology of Dam Site (non-cohesive soil type ground), (
    9
    ) Era of Construction (prior to 1891) and (10) Soil Properties of Embankment (sand, not silty sand or gravel, penetration resistance that is 10% smaller than the undamaged dams).
  • 石原 研而, 長尾 哲
    土質工学会論文報告集
    1983年 23 巻 1 号 19-37
    発行日: 1983/03/15
    公開日: 2008/02/29
    ジャーナル フリー
    Using the so-called pseudo-static method, a stability analysis was made for the mountain slide that took place at Mitake-iriya village at the time of the Izu-Ohshima-Kinkai earthquake of January 14, 1978. Undisturbed samples of volcanic clay were obtained in blocks from the exposed surface of the deposit identified to have been the sliding surface. The partially saturated clay samples were tested under consolidated undrained conditions using the triaxial test equipment. Dynamic axial stresses with irregular time histories were applied to the specimens in combination with statically sustained axial stresses to determine the soil strength under the conditions simulating in-situ states of stress during the earthquake. The results of the tests were expressed in terms of the Mohr-Coulomb type failure criterion which showed that, while the angle of internal friction remained almost unchanged, the cohesion component in irregular loading increased above values obtained in the static loading. Using the strength parameters thus determined, a pseudo-static analysis was made to check the stability of the soil masses that had actually slid during the 1978 earthquake. The maximum horizontal acceleration required to cause the slide was computed. The computed accelerations were shown to cover a range between 400 and 500 gals which is consistent with the range estimated by other investigators on the basis of overturning of tombstones in the vicinity of the slide area.
  • 尾形 強, 佐藤 治代, 吉田 弘, 猪川 三郎
    日本化学会誌(化学と工業化学)
    1974年 1974 巻 2 号 382-385
    発行日: 1974/02/10
    公開日: 2011/05/30
    ジャーナル フリー
    The Beckmann rearrangement of aliphatic ketone oximes, R(CHs)C=NOH (R=Et (1); n-Pr (
    2
    ); iso-Pr (3); iso-Bu (
    4
    )), with polyphosphoric acid (PPA), polyphosphate ester (PPE), and ester of phosphoric acid (
    2
    P-5 R) was carried out and migratory ratios ((a)/(
    b
    ) in eq. (1)) were determined, The results are shown in Fig.1,
    2
    , and 3, respectively.
    In Fig.1 and
    2
    , the migratory ratios decrease with reaction time and nearly approach to the ratios of anti-alkyl form/syn-alkylform in benzene(A1) or DMSO(A
    2
    )except for (3) (See Table 1). From this fact, it has been found that PPA and PPE are inactive for isomerization of the oximes andanti-alkyl oximes rearrange faster than syn-alkyl ones. ln the case of (3), migratery ratios are smaller than Ai or A
    2
    . As acetonitrile is detected by GLC, it is presumed that fission has been occurred simultaneously with rearrangement in anti-alkyl oxime (eq. (3)). In the case of
    2
    P-5 R, all modes of the reaction arethe same as in above, except that the rate of fission is tnuch faster than that in PPA and PPE.
    The reaction of anti-alkyl ketone oximes having a bulky grouphas been greatly influenced by the use of sterically demanding catalysts such asPPA, PPE, and
    2
    P-5 R.
  • /, 三浦 哲彦, NORIHIKO MIURA
    地盤工学会論文報告集
    1996年 36 巻 4 号 11-22
    発行日: 1996/12/15
    公開日: 2008/02/29
    ジャーナル フリー
    A new analytical method is proposed for determining the inextensible grid reinforcement pullout resistance and pullout force/pullout displacement curve by using basic backfill soil and grid reinforcement properties. The pullout skin friction resistance/pullout displacement relationship is simulated by linear elastic-perfectly plastic model. A hyperbolic model has been proposed to represent the pullout bearing resistance/pullout displacement relationship in which the maximum bearing resistance of a single bearing member is determined using a new bearing capacity equation proposed in this paper. The influences of the grid bearing member spacing ratio, S/
    D
    , the bearing member deflection rigidity, and the pullout softening behavior on the mobilization of pullout bearing resistance are explicitly included in the proposed model. Good agreement has been obtained between calculated values and laboratory test results.
  • 澁谷 啓, 田中 洋行
    地盤工学会論文報告集
    1996年 36 巻 4 号 45-55
    発行日: 1996/12/15
    公開日: 2008/02/29
    ジャーナル フリー
    An empirical equation in use for estimating the pseudo-elastic shear modulus, Gf, of subsoil, associated with shear strains less than 0.001% is proposed in this paper. In a series of in-situ seismic cone tests performed nationwide, the profiles of both Gf and the in-situ void ratio,
    e0
    , with depth were successfully characterised at five sites, each comprising a soft clay layer deposited in the Holocene era. The database which comprised the original data from the field and laboratory tests, coupled with similar information on well-documented Holocene clay deposits in Europe, was statistically analyzed in attempts to determine a generalised relationship with which Gf of soft clay may be reasonably estimated only from routinely available borehole data; that is
    e0
    and the current geostatic effective overburden pressure, σ'v. An empirical relationship, Gf=5, 000
    e0
    -1.5√(σ'v) (kPa), was derived from the statistical analysis applied to data from seven different clays worldwide, for which
    e0
    extended over a range between 1 and 5, and the overconsolidation ratio ranged roughly between 1 and
    2
    . The applicability of the proposed relationship was evaluated for two case records, each in which the clay exhibited unusual behavior; i.
    e
    ., the undrained shear strength remained more or less constant with depth due to the existence of artesian pressure at one site, and, at the other, Gf decreased, whereas
    e0
    increased, with depth. It was demonstrated that even in these clay deposits exhibiting exceptional profiles, the proposed relationship was capable of predicting Gf with a reasonable accuracy by determining the profiles of
    e0
    and σ'v with depth. In addition, the prediction when compared to Gmax from carefully performed laboratory cyclic tests, yielded a better estimate of Gf from the in-situ seismic survey. Despite the fact that the empirical relationship was initially designated to estimate Gf of soft clays, it may be equally applicable to sandy deposits. This was verified by comparing it to similar, and well-established, relationships developed for sands. A case record as such is also described for a loose sand deposit at Higashi-Ohgishima in Tokyo Bay which was placed in 1960's by land reclamation.
  • Hiroyuki HIRAOKA, Naoki MORI, Ritsuo NISHIDA, Yasumasa KUWAHARA
    Bioscience, Biotechnology, and Biochemistry
    2001年 65 巻 12 号 2749-2754
    発行日: 2001年
    公開日: 2002/08/30
    ジャーナル フリー
    A mixture of two monoterpenes was obtained as the opisthonotal gland secretion from unidentified Histiogaster sp. A096 (Acari: Acaridae), and their structures were elucidated to be (
    4
    E
    )-dehydrocitrals[(
    2
    E
    ,
    4
    E
    )- and (
    2
    Z,
    4
    E
    )-3,
    7
    -dimethyl-
    2
    ,
    4
    ,
    6
    -octatrienals] by GC/MS, GC/FT-IR, UV and 1H-NMR spectra. Both isomers of (
    4
    E
    )-dehydrocitral prepared by syntheses in
    4
    steps from 3-methyl-
    2
    -butenal with 34.
    2
    % yields (based on the ylide) were separated by column chromatography into the (
    2
    E
    ,
    4
    E
    )- and (
    2
    Z,
    4
    E
    )-3,
    7
    -dimethyl-
    2
    ,
    4
    ,
    6
    -octatrienal. Mass spectra together with GC retention times of the purified natural (
    4
    E
    )-dehydrocitrals were identical with those of synthetic (
    2
    E
    ,
    4
    E
    )-3,
    7
    -dimethyl-
    2
    ,
    4
    ,
    6
    -octatrienal and (
    2
    Z,
    4
    E
    )-3,
    7
    -dimethyl-
    2
    ,
    4
    ,
    6
    -octatrienal. The geometry at the
    2
    -C position of both synthetic (
    4
    E
    )-dehydrocitrals was confirmed by NOESY analyses. This is the first identification of (
    4
    E
    )-dehydrocitrals from the animal kingdom.
  • Luis
    E
    . VALLEJO, VINCENT A. SCOVAZZO
    地盤工学会論文報告集
    2003年 43 巻 2 号 129-133
    発行日: 2003/04/15
    公開日: 2008/02/29
    ジャーナル フリー
    When a mudflow moves down a slope, the gravity induced shear stress, τ, is opposed by the combined effect of the undrained shear strength, cu, of the mud, and its viscosity, η, which is associated with the velocity gradient in the mudflow, dv/dy. In equation form this can be expressed as : τ= cu+η(dv/dy). The resistance provided by the mud involves the contribution of both cu and η. For an understanding of the mobilization mechanics of mudflows, one needs then these two parameters. This study describes two methods that can be used to determine these parameters. The cu of the muds is measured using a cylinder-strength meter devise. The technique associated with this devise consists in lowering a cylinder of known dimension and weight into a mud sample, measuring the depth of penetration of the cylinder into the mud, and calculating the strength, cu, of the mud required to support the solid cylinder at that depth. The cu of the mud is calculated using Sokolovski's theory designed to calculate the indentation pressures developed by a Tresca plastic when a cylinder penetrates it. The determination of the viscosity, η, of the mud is obtained from either the velocity measurements of the free surface of the mudflow, or from the difference between the velocity of the free surface of the mudflow and its velocity at the interface between the mudflow and the surface on which it moves. The viscosity η is obtained from a relationship that relates these velocities with η.
  • M. K. Banerjee, P. S. Banerjee, S. Datta
    ISIJ International
    2001年 41 巻 3 号 257-261
    発行日: 2001/03/15
    公開日: 2007/05/31
    ジャーナル フリー
    A boron treated copper bearing HSLA steel containing austenite formers like manganese and nickel, somewhat lower in amount than that in HSLA 100 variety of steel is chosen for the study. The role of thermomechanical processing on the microstructure and mechanical properties of the above steel has been investigated. Differential scanning calorimetric study is carried out for understanding the precipitation behaviour of copper in HSLA steel under the influence of boron. The microstructure of the experimental steel is found to consist of laths of martensites and bainite. MA constituents of ribbon like morphology are observed at the lath boundaries. Higher strength properties of the steel are attributed to the presence of finely distributed precipitates of copper and microalloy carbides.
  • 佐藤 敬之輔
    デザイン学研究
    1970年 1970 巻 11 号 45-55
    発行日: 1970/03/30
    公開日: 2017/07/25
    ジャーナル フリー
    [1] The purpose of this reserch is to make clear what type of design can give good effects to win the high readership score. At the begining I had to know what factors decide the readership score, and how to change the quality of the desing into numerical value. I have used the method of multi-dimentional analysis with the help of a computer, and got the estimation formula, with
    7
    kinds of factors, as follows ; A^^〜=
    B
    +C+
    D
    +K+aE+
    bF
    +cG. A^^〜=estimated values of the readership score. 1)
    B
    , C,
    D
    , K : these four factors are given as category values (so we call them); each factor is classified into several categories.
    B
    =week day, classified into
    7
    categories. C=pages of a newspaper, which are characterized by the kinds of articles, news, and the other reading matters, classified into
    22
    categories.
    D
    =kinds of goods and trades of the advertizement, classified into 14 catedories. K=constants, given to each 13 surveys.
    2
    )
    E
    , F, G : these factors are given as numerical values. G=area of advertizement, measured by the unit of column in the whole page length, being classified into
    6
    kinds of area (
    2
    .5, 3.5, 5,
    7
    , 10, 15) and 15 column means a whole page, about
    2
    ,000cm^
    2
    .
    E
    , F are the marks obtained in the design of advertizements.
    E
    =sum of the marks obtained in each design element on the advertizement. F=the marks obtained on the whole effect of the design. 3) a,
    b
    , c : coefficients Using the above formula with the category values and the coefficients, we can obtain the naked design effect from the actual value A of readership score: aE+
    bF
    =A-(
    B
    +C+
    D
    +K+cG). In this research, I used 1,829 data of readership score from 1960 to 1968, being obtained by 13 survevs, spring and autumn twice a year. The sample of size each survey was 3,541,
    2
    ,251, or 200 in the other 11 surveys. Multiple correlation coefficient between the estimated value A^^〜 and the actual value A is 0.951. The table
    2
    ^* shows the contribution indexes of each factor by 3 kinds of expression-(1) Range : the absolute difference between the maximum and the minimum category values, (
    2
    ) Standard deviations of the category values, (3) Partial correlation coefficient : the relationship between the actual values A and each factors. *see the table
    2
    in the thesis in Japanese. [
    2
    ] The important point was in the determination of the values of
    E
    , F.
    E
    is the sum of the marks obtained in each design element, classified into four kinds :
    E
    =
    E
    _1+
    E
    _
    2
    +
    E
    _3+
    E
    _
    4
    . design elements [table]
    E
    _1,
    E
    _
    2
    ,
    E
    _3,
    E
    _
    4
    , these values have the 5 grades, as 0, 1,
    2
    , 3,
    4
    and 0 is given to the design that has no attractive effect or no applicable element. And
    E
    obtain the marks of 0 to
    9
    grades as the sum of them. The values of F have also 5 grades, 0 to
    4
    . The principles to determine the values of
    E
    , F are as follows : a) The marks obtained of
    E
    , F must be the relative values among the each survey, and at the same time, they must have constancy within the same survey-the same elements of design must win the same marks obtained.
    b
    ) They must be determined as to win the highest multiple correlation coefficient, when they are put into the estimation formula. c) They must be reasonable. In order to justify them, we must carry many researches on the actual condition. The frequency of accurence of each grade of
    E
    , F values, as the table 5-
    4
    , and 5-5 in the thesis in Japanese.
  • 西村 聡, 東畑 郁生, 本多 剛
    地盤工学会論文報告集
    2002年 42 巻 4 号 89-98
    発行日: 2002/08/15
    公開日: 2008/02/29
    ジャーナル フリー
    The rate dependent nature of liquefied sand was investigated by laboratory shear tests. Since previous experience has revealed the many difficulties inherent in maintaining the state of liquefaction of a sandy specimen, new measures were attempted. The test results indicate that the measured shear stress consists of frictional and rate dependent components, and a viscosity coefficient was assessed from the latter component. The measured viscosity varies with the rate of strain as well as the magnitude of strain itself. A similar test on a dry specimen revealed less viscosity and implied that a major part of rate dependency comes from the behavior of pore liquid in the case of water-saturated sand. It was interesting, moreover, that sand with fines was of less viscosity. Finally, a numerical analysis was conducted on a real liquefaction-induced ground deformation and the results were consistent with the observation.
  • STEFANIA SICA, LUCA PAGANO
    SOILS AND FOUNDATIONS
    2009年 49 巻 6 号 921-939
    発行日: 2009年
    公開日: 2011/01/27
    ジャーナル フリー
    The paper illustrates theoretical and experimental procedures adopted to characterize the seismic response of earth dams by performance-based criteria. The study refers to a real case, the Camastra Dam, a zoned earth dam with vertical clay core, placed in a highly seismic zone of Southern Italy. At first, the analysis objectives have been identified along with the physical quantities needed to achieve them for characterizing dam seismic performance. A theoretical approach, consistent with the identified analysis objectives, has been later selected. The adopted approach is based on continuum mechanics and accounts for coupling between soil skeleton and pore water phase. It is also able to describe the main features of soil response under cyclic loading conditions since it implements an advanced constitutive law for the soil skeleton. Big effort has been paid to the mechanical characterization of the dam materials. In addition to data coming from the interpretation of the laboratory tests performed at the time of dam construction, in situ tests (SASW, Down Hole, DMT) have been recently carried out on the embankment and foundation soils and interpreted consistently with the requirements of the selected theoretical model. Preliminarily, the static stages of the dam lifetime have been numerically simulated to reproduce the behaviour observed in terms of cross-arm settlements and pore water pressures, in order to obtain or verify some soil parameters and initialize the state variables for the simulation of the seismic stages. A seismological study of the dam site provided the expected seismic scenarios in terms of time histories of acceleration, needed as input for the dynamic analyses. The seismic response of the Camastra Dam was finally investigated and discussed in the light of performance-based criteria.
  • LUCA PAGANO, STEFANIA SICA, POMPEO COICO
    SOILS AND FOUNDATIONS
    2009年 49 巻 6 号 909-920
    発行日: 2009年
    公開日: 2011/01/27
    ジャーナル フリー
    A crucial matter related to roads in seismic areas is to ensure viability during the post-seismic stages, especially if the road represents an important or unique way to reach towns that may be potentially hit by strong earthquakes. Verification of road viability under seismic actions requires not only safety assessment of the failure mechanisms which may jeopardize single road components (embankment, viaduct, bridge, etc.) but also evaluation of performance. Viability of a road may be compromised by an unsatisfactory response of road embankments. The vehicle flux may be, in fact, inhibited or reduced if a road embankment suffers global instability mechanisms or significant permanent displacements mainly at the contact with structural elements (
    e
    .g., viaducts, bridges) that do not move significantly. In this case the embankment permanent displacements turn out into steps or separations. The paper accounts for the different stages followed to study the seismic performance of the road embankments located along a sample road branch of about 5 km. Preliminary activities consisted in characterizing the geological area of the sample road, in selecting the potentially vulnerable embankments and in carrying out in-situ investigations to properly characterize the physical and mechanical properties of the embankments and foundation soils. A seismological study of the sample area was performed in order to characterize the reference seismic actions needed for the numerical analyses. The seismic response of the embankments was evaluated by a pseudo-dynamic approach and an advanced dynamic model. In the latter, the equations describing dynamic equilibrium and compatibility were merged with an elastoplastic combined-hardening constitutive law that properly models soil response under cyclic loads. The embankment's seismic performance was predicted in terms of permanent settlements at the embankment top surface versus the peak acceleration of the reference input motions.
  • LIPING WANG, GA ZHANG, JIAN-MIN ZHANG
    SOILS AND FOUNDATIONS
    2010年 50 巻 4 号 459-469
    発行日: 2010年
    公開日: 2010/12/21
    ジャーナル フリー
    Soil nails have been widely used to retain excavations and stabilize steep cutslopes. A series of dynamic centrifuge model tests were conducted on nail-reinforced and unreinforced slopes during an earthquake, with several influence factors, including the nail length, nail spacing, and the inclination of slope, taken into consideration. The unreinforced slope exhibited a progressive failure in the middle and lower parts though the global slip surface did not appear due to the earthquake, which was arrested by using the nail reinforcement. The nails changed the dynamic acceleration response of the slope during the earthquake. The deformation of the slope was significantly decreased by the nails within a nail-influence zone. This zone involved the slip surface of the unreinforced slope, and was almost completely independent on the layout of the nail-reinforcement when the nails had sufficient length. A point couple analysis, a strain analysis, and a uniformity analysis were carried out in an attempt to determine why nails can increase the stability of a slope. It was discovered that the nails forced the deformation of the slope to be more uniform and thus arrested possible strain localization under earthquake conditions. As such, it is suggested that increasing nail length or decreasing nail spacing can both improve the nail-reinforcement effect, and increase the stability level of a slope.
  • 澁谷 啓, 三田地 利之
    土質工学会論文報告集
    1994年 34 巻 4 号 67-77
    発行日: 1994/12/15
    公開日: 2008/02/29
    ジャーナル フリー
    In this paper, consideration is given as to how to characterize depth-variation for the small-strain shear modulus of natural clay sedimentation, in a state of normal consolidation. A case study was carried out for a relatively uniform clay layer deposited in the Holocene era. Initially, the effects of both strain and in-situ stress levels on secant shear modulus were carefully examined in cyclic torsion shear tests using undisturbed samples, which were recovered at different depths in a test borehole. The range of shear strain examined was between 0.001% and 1%. Similar examination was made for a silty clay using reconstituted samples that were isotropically consolidated at different stress levels. On the basis of the results of these laboratory tests, together with the shear modulus from an in-situ seismic survey, the small-strain shear modulus was formulated in terms of the stress and strain levels, and linked also to undrained shear strength. Interactions of the small strain stiffness between in-situ and laboratory are discussed in depth with an attention paid to the existing aging effect in the original subsurface condition.
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