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ESTIMATE OF ELASTIC SHEAR MODULUS IN HOLOCENE SOIL DEPOSITS

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

DOI https://doi.org/10.3208/sandf.36.4_45

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An empirical equation in use for estimating the pseudo-elastic shear modulus, G_f, 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 G_f 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 G_f 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, G_f=
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, G_f 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 G_f with a reasonable accuracy by determining the profiles of
e₀
and σ'_v with depth. In addition, the prediction when compared to G_max from carefully performed laboratory cyclic tests, yielded a better estimate of G_f from the in-situ seismic survey. Despite the fact that the empirical relationship was initially designated to estimate G_f 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.
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GEOTECHNICAL SIMULATION TEST FOR THE NIKAWA LANDSLIDE INDUCED BY JANUARY 17, 1995 HYOGOKEN-NAMBU EARTHQUAKE

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

DOI https://doi.org/10.3208/sandf.40.35

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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.
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SMALL STRAIN SHEAR MODULUS OF CLAY SEDIMENTATION IN A STATE OF NORMAL CONSOLIDATION

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

DOI https://doi.org/10.3208/sandf1972.34.4_67

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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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LABORATORY SHEAR TESTS ON VISCOUS NATURE OF LIQUEFIED SAND

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

DOI https://doi.org/10.3208/sandf.42.4_89

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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.
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脂肪族ケトンオキシムのポリリン酸,ポリリン酸エステル,およびリン酸エステルによる Beckmann 転位反応-相対転位比の経時変化について-

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

DOI https://doi.org/10.1246/nikkashi.1974.382

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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(A2)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 A2. 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.
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EFFECT OF PRELOADING ON POST-CONSTRUCTION CONSOLIDATION SETTLEMENT OF SOFT CLAY SUBJECTED TO REPEATED LOADING

藤原東雄, 上俊二

土質工学会論文報告集
1990年 30 巻 1 号 76-86
発行日: 1990/03/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf1972.30.76

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The behavior of the soft clay grounds subjected to repeated loading is different from that subjected to sustained loading. The difference in settlement between these two loading patterns should be due to secondary compression over a long period of time. Consequently, soft clay grounds subjected to repeated loading tend to be more compressible than those subjected to sustained loading. Therefore, it is necessary for engineers to predict post-construction settlements under repeated loading. In this respect, the preloading is considered to be promising as a countermeasure to reduce the settlement of clay under repeated loading as well as under sustained loading. The effect of preloading on post-construction consolidation settlement of soft clay subjected to repeated loading after removal of a part of preload is investigated in the present paper. It has become clear that the settlement of a clay sample after preconsolidation is mainly affected by the amount of preload, the degree of consolidation due to the preload, the amount of permanent load and the amount of repeated load after removal of preload. The calculated settlement versus time relations using a method to estimate the amount of consolidation settlement of soft clay grounds subjected to repeated loading after removal of preloading were compared with the observed degree of consolidation as parameters of the intensities of preload and repeated load.
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CONSTITUTIVE RELATIONS FOR SAND UNDER CYCLIC LOADING BASED ON ELASTO-PLASTICITY THEORY

西好一, 金谷守

土質工学会論文報告集
1990年 30 巻 2 号 43-59
発行日: 1990/06/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf1972.30.2_43

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In this paper, constitutive relations for expressing the inelastic behavior of sandy ground expected at the time of a strong earthquake are proposed. These constitutive relations are formulated by a yield function in terms of effective stress ratio and by a plastic potential function which is derived from the stress ratio-plastic strain incremental ratio defined as a function of accumulated volumetric strain. These constitutive relations employ Sekiguchi and Ohta's stress parameter to take account of the effects of rotation of principal stress axis on the deformation characteristics of sand. The Masing rule is modified in such a way that it can be used in the multi-dimensional stress field, and employed in the hardening function in order to express a hysteretic damping. Material constants contained in the proposed constitutive relations can be easily determined by the mechanical tests which are normally conducted in laboratory. The comparison between predicted behaviors by the constitutive relations and results of undrained cyclic shear tests shows that the dynamic strength-deformation characteristics of sand in a wide range of density can be simulated satisfactorily.
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顎関節症における関節円板のMRIによる検討

関節円板の前方転位の程度と復位および臨床所見との関係

松木宏真, 尾崎登喜雄

日本口腔外科学会雑誌
1999年 45 巻 4 号 241-251
発行日: 1999/04/20
公開日: 2011/07/25

DOI https://doi.org/10.5794/jjoms.45.241

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To determine the position of the anteriorly displaced articular disc, we examined temporomandibular joints by magnetic resonance imaging (MRI) in 54 patients with unilateral temporomandibular joint dysfunction. MRI was done before conservative therapy in the occlusal and maximal open-mouth position. We drew a straight line connecting the lowest point of the articular eminence (point A) and the highest point of the external acoustic pore (point
E
) by tracing the sagittal view on MRI. On the standard A-
E
line, points B', C', and
D
' were sought by dropping perpendicular lines from the deepest point of the glenoid fossa (point B), the highest point of the condylar head (point C), and the most posterior point of the articular disc (point
D
). We then determined the sagittal position of the articular disc in the glenoid fossa by measuring the distances
AD
' and C'
D
' and sought the correlation between these distances and clinical findings. The results were as follows. 1. The distance
AD
' in 33 patients with MRI-defined irreversible displacement of the disc was shorter than that in 10 patients with reversible displacement (3.7±1.
9
mm vs
6
.
8
±2.0mm, p<0.0001). In contrast, the distance C'
D
' in the former was longer than that in the latter (
6
.0±1.7mm vs 3.4±1.
5
mm, P<0.0001). Of 29 discs displaced anteriorly less than
5
mm in distance C'
D
', 19 (66%) had reversible or no displacement. However, 23 (
92
%) of 25 discs displaced more than
5
mm in distance C'
D
' had irreversible displacement. 2. Disc deformity and abnormal signal intensity bands in the condylar head closely correlated with distances
AD
' and C'
D
'. In 17 patients without disc deformity, mean
AD
' and C'
D
' distances were
9
.
8
± 2.7mm and 0.2± 2.
8
mm, respectively. In 19 and 18 patients with mild to moderate and severe deformity, the mean
AD
'(C'
D
') distances were
5
.4±1.
8
mm (4.
5
±1.
6
mm) and 2.7±1.
8
mm (
6
.
8
±1.
5
mm), respectively. 3. Although distance
AD
' and C'
D
' did not correlate with clinical symptoms, the degree of anterior disc displacement correlated with the therapeutic effect of conservative therapy. The mean
AD
' distance (7.3±3.7mm) in 15 patients with a complete response to conservative therapy was longer than that (3.4±1.4mm) in
5
patients with no improvement. These results indicate that the sagittal position of the articular disc can be determined by MRI and that successful conservative therapy is unlikely if anterior disc displacement extends beyond
5
mm from the top of the condylar head, often resulting in irreversible displacement.
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THERMOPLASTIC MODELING OF UNDRAINED FAILURE OF SATURATED CLAY DUE TO HEATING

TOMASZ HUECKEL, RITA PELLEGRINI

土質工学会論文報告集
1991年 31 巻 3 号 1-16
発行日: 1991/09/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf1972.31.3_1

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This paper is concerned with modeling of thermomechanical failure of triaxial specimens of saturated clays of low porosity. Thermomechanical failure manifests itself in undrained conditions as a development of advanced irreversible strains due to heating under constant total stress. In experiments on two clays the failure occured at temperatures from 70° to
90
°C. The observed failure is associated with a pore water pressure buildup. Models of thermoplastic behavior of skeleton and of thermal volume changes of adsorbed water are employed to interpret and numerically simulate the test results. Using these models, thermomechanical failure was found to occur when the effective stress is brought to the critical state by expansion of pore water and thermoplastic compressive strain in skeleton.
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MECHANISM FOR WATER FILM GENERATION AND LATERAL FLOW IN LIQUEFIED SAND LAYER

國生剛治

地盤工学会論文報告集
2000年 40 巻 5 号 99-111
発行日: 2000/10/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf.40.5_99

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In view of the significant role of the water film effect in flow failure for a liquefied sandy deposit, the mechanism of water film generation is numerically studied based on a 1-dimensional model test. The process of water film growth and decay can be simulated to a certain extent by a simple consolidation analysis, which indicates that only a small difference in permeability in layered sand is enough for a water film to develop. A 1 G shaking table test for a two-dimensional slope model with an arc of silt within a saturated sand is then addressed to discuss the dilatancy effect exerted in sheared sand during flow failure. It is possible that, once the water film is formed, the transmission of shear stress through it is interrupted, leaving the sand below free from the dilatancy ; this eventually allows the water film to stay without being absorbed during flow failure. The result of another shaking table test for a trapezoidal slope with horizontal silt seams indicate that water films beneath the seams enable the soil mass above them to laterally flow along water films very gently inclined even after shaking. If a silt seam breaks due to excessive pressure in the water film, it triggers re-liquefaction in the upper sand and leads to further instability.
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FREQUENCY DEPENDENT PROPERTY OF WAVES IN SATURATED SOIL

三浦均也, 吉田望, 金潤相

地盤工学会論文報告集
2001年 41 巻 2 号 1-19
発行日: 2001/04/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf.41.2_1

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Elastic wave propagation in saturated soil is investigated in order to grasp the frequency dependent wave propagation property of actual soil. First, a closed form solution of Biot's equation is derived under a one-directional wave propagation condition. Then, the frequency dependent properties of waves in various soils such as clay, silt, sand, gravel and soft rock are computed and discussed. The behavior is shown to be classified into three states : low frequency, high frequency and transient. Properties hardly change in the low and high frequency states. The degree of saturation is shown to hardly affect the shear wave property, but it greatly affects the dilatational wave property, especially in a highly saturated condition. Permeability hardly affects the properties at low and high frequency states, but it does change the frequency range of the transient state. Next, the applicability of Biot's formulation is examined and the high frequency state derived from Biot's equation is shown to be valid when permeability is larger than that of silt. Finally, it is shown that various mechanical properties can be evaluated using the frequency dependent characteristics of the wave, some of which are difficult to measure in situ with conventional tools.
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LIQUEFACTION-INDUCED FLOW FAILURE OF EMBANKMENTS AND RESIDUAL STRENGTH OF SILTY SANDS

石原研而, 安田進, 吉田喜忠

土質工学会論文報告集
1990年 30 巻 3 号 69-80
発行日: 1990/09/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf1972.30.3_69

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Failure modes of embankments or slopes consisting of saturated cohesionless soils during earthquakes may be classified into two types, the one involving a limited amount of permanent deformation such as settlements or lateral bulging on the order of tens of centimeter to meters, and the other in which complete slumping or flow of materials takes place through distances of tens of meters. Associated with seismic risk evaluation of embankments, there are many cases where the occurrence of limited deformation is tolerated but the flow type of failure is never permissible. In such a case, a methodology becomes necessary for evaluating the safety of embankments against the flow type of failure, once it occurs. Post-earthquake stability analysis in which the conventional analysis is made by employing residual strength or steady-state strength of soils is used for this purpose. However, accurate evaluation of in-situ residual strength is a difficult task particularly for cohesionless soils. Thus, it would appear useful if estimates of the residual strength can be made based on the back analysis of several embankments that have suffered the flow type failure during past earthquakes. In the present study, slope stability analyses were made for several earthquake-damaged embankments and tailings dams composed of silty sands or sandy silts to back-calculate the value of residual strength. The ground conditions at the failure sites were investigated by means of the Dutch cone penetration test or by the Swedish cone test. By comparing the values of the back-calculated residual strength with those of the cone resistance, empirical correlations between them are obtained which may be used in turn for the evaluation of residual strength of similar soils on other sites.
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DAMAGE TO RIVER DIKES

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

DOI https://doi.org/10.3208/sandf.36.Special_235

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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.
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FULL-SCALE EMBANKMENT CONSOLIDATION TEST USING PREFABRICATED VERTICAL THERMAL DRAINS

CHANIDNUN POTHIRAKSANON, DENNES T. BERGADO, HOSSAM M. ABUEL-NAGA

SOILS AND FOUNDATIONS
2010年 50 巻 5 号 599-608
発行日: 2010年
公開日: 2010/12/28

DOI https://doi.org/10.3208/sandf.50.599

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In this study the field feasibility of an innovative thermal technique to improve the performance of prefabricated vertical drains (PVD) used in conjunction with the preloading ground improvement method is investigated. For this purpose, two identical
6
.0 m high full-scale test embankments for preloading were constructed over the soft Bangkok clay where a conventional PVD system was installed underneath one embankment and a novel prefabricated vertical thermo-drain (PVTD) system was utilized for the other. The PVTD unit consists of a U-tube made of cross-linked polyethylene plastic (PEX) that is attached to a conventional PVD unit. Preheated water at about
90
°C is circulated through the attached U-tube to raise the soil temperature underneath the PVTD embankment. The behavior of the two test embankments were compared in terms of excess pore water pressure and consolidation results. The comparison shows the advantage of a PVTD system over a conventional PVD system. The rate of consolidation increases significantly in the PVTD system due to the temperature effect on the hydraulic conductivity. Moreover, the embankment with the PVTD system generates more settlement due to the thermally induced irreversible contraction of saturated normally consolidated soft Bangkok clay.

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5
a-
E
-
6
65MeVにおける^<
92
>Mo(p^^→,
d
)反応

久持康平, 岩本修, 木佐貫明, ブディハルジョストモ, ウィドドスシロ, 納富昭弘, 魚住裕介, 榮武二, 的場優, 中野正博, 牧孝

秋の分科会予稿集
1992年 1992.1 巻 5a-E-6
発行日: 1992/09/14
公開日: 2018/03/22

DOI https://doi.org/10.11316/jpsgaiyok.1992.1.0_133_2

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22
a-
D
-
8
ハイペロン-核子散乱実験(KEK-PS
E
289)IV

神田浩樹, 秋川藤志, 延与秀人, 福田共和, 舟橋春彦, 後藤雄二, 長谷山智仁, 早川徹, 市川温子, 家入正治, 飯沼昌隆, 今井憲一, 石野雅也, 伊藤好孝, 川畑貴裕, 近藤恭弘, 政池明, 松田恭之, 三原智, 中田陽子, 中井浩二, 中澤和馬, 小沢恭一郎, 斎藤直人, 佐藤朗, 佐藤博紀, 田原司睦, 竹内富士雄, 滝伴子, 鳥井久行, 山本和弘, 山下了, 吉田充, 吉村善朗, Jung Keun AHN, Jacques ARVIEUX, Bernd BASSALLECK, Myung Shin CHUNG, Serguei GOLOVKINE, Alexandre GORIN, Yeong Duk KIM, Eugene KOZARENKO, Igor KRESLO, Jong Man LEE, Yeong Mouk PARK, Iouri PETOUKHOV, Yong Moo SHIN, Kwang Souk SIM, Pavel TLUSTY,
E
289 collaboration

日本物理学会講演概要集
1997年 52.2.1 巻 22a-D-8
発行日: 1997/09/02
公開日: 2018/03/04

DOI https://doi.org/10.11316/jpsgaiyo.52.2.1.0_60_3

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RESPONSE OF A DENSE SAND DEPOSIT DURING 1993 KUSHIR0-0KI EARTHQUAKE

井合進, 森田年一, 亀岡知弘, 松永康男, 安彦和之

土質工学会論文報告集
1995年 35 巻 1 号 115-131
発行日: 1995/03/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf1972.35.115

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In the 1993 Kushiro-oki Earthquake of Richter magnitude 7.
8
, simultaneous recording of earthquake motions was successfully made at the ground surface and at a depth of 77 meters in a dense saturated sand deposit. The peak horizontal acceleration was 0.47 g on the ground surface and 0.21 g at a depth of 77 meters. The acceleration record at the ground surface showed a distinctive ground response, which consisted of a cyclic motion having a period of about 1.
5
seconds overlain by a spike at each peak of the motion. In order to study the mechanism of this peculiar ground response, effective stress analysis was conducted on the dense saturated sand deposit. The model used for this study was a strain space multiple mechanism model, which takes into account the effect of principal stress axis rotation. The recorded earthquake motion at a depth of 77 meters was used as the input earthquake motion for the analysis. Sampling after in-situ freezing was done in order to evaluate the properties of the sand. The results of the analysis indicated that the observed ground response was due to the effect of dilatancy of sand, which plays a significant role in the response of the dense saturated sand deposits during strong earthquake motions.
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中年肥満男性における運動実践が内臓脂肪に及ぼす影響：食事改善との比較

笹井浩行, 片山靖富, 沼尾成晴, 中田由夫, 田中喜代次

体力科学
2008年 57 巻 1 号 89-100
発行日: 2008/02/01
公開日: 2008/08/06

DOI https://doi.org/10.7600/jspfsm.57.89

ジャーナルフリー

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It has been reported that visceral fat (VF) is an independent predictor of the incidence for coronary heart disease, and is associated with its risk factors. The independent effects of exercise or dietary modification on VF remain to be fully elucidated, especially in obese middle-aged men. The purpose of this study was to investigate effects of exercise on VF compared to dietary modification. Thirty-five obese middle-aged men participated in this study. They consisted of exercise group (n=
22
, 51.4±11.
6
yr, Group
E
) and diet group (n=13, 48.
8
±12.2 yr, Group
D
). Participants in Group
E
followed
90
-min exercise sessions on a regular basis 3 days per week for 12 weeks. Participants in Group
D
attended weekly classes aimed at maintaining well-balanced 1,680 kcal/
d
diet for 12 weeks. Body weight decreased significantly in both groups (Group
E
: −2.
9
kg, Group
D
: −
5
.4 kg). Visceral fat area (VFA) determined by computed tomography also decreased significantly (Group
E
: −32.0 cm², Group
D
: −39.4 cm²). An analysis of covariance adjusted by weight change revealed no significant group difference in VFA change. These results suggest that exercise-induced negative energy balance does not result in greater decrease in VFA as compared with dietary modification alone.
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(
22E
, 24S)
5α
-Stigmasta-3,
22
-dien-
6
-one: An Intermediate of the Isomerization of (
22E
, 24S)-3α,
5
-Cyclo-
5α
-stigmast-
22
-en-
6
-one into (
22E
, 24S)-
5α
-Stigmasta-2,
22
-dien-
6
-one

Suguru TAKATSUTO, Kiyomi KOBAYASHI, Tsuyoshi WATANABE, Hiroki KURIYAMA, Tokuo FURUSE

Agricultural and Biological Chemistry
1988年 52 巻 12 号 3217-3218
発行日: 1988年
公開日: 2006/04/05

DOI https://doi.org/10.1271/bbb1961.52.3217

ジャーナルフリー

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SEISMIC STABILITY OF CEMENT TREATED GROUND BY TILTlNG AND DYNAMIC SHAKlNG TABLE TESTS

北誥昌樹, 早野公敏, 橋爪秀夫

地盤工学会論文報告集
2003年 43 巻 6 号 125-140
発行日: 2003/12/15
公開日: 2008/02/29

DOI https://doi.org/10.3208/sandf.43.6_125

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A series of tilting tests and shaking table tests was conducted with a geotechnical centrifuge apparatus to determine the dynamic active earth pressure of cement treated clay ground by investigating the seismic stability of cement treated clay ground having an unsupported vertical slope. In the tilting tests, the horizontal seismic inertia force was simulated statically by tilting the whole model ground in accordance with the horizontal seismic coefficient k_h. The tilted model ground was subjected to monotonically increasing centrifugal acceleration until it failed due to the enhanced selfweight. In the shaking table tests, on the other hand, the model ground was subjected to dynamic excitations under a high centrifugal acceleration field. The magnitude of the dynamic excitation was increased stepwise until the model ground failed. It was found from both test results that the model ground failed with a combination of a vertical tensile crack and a straight shear failure plane, which was much different from the failure phenomenon of sandy or clayey ground. It was also found that the conventional pseudo-static limit equilibrium method such as Mononobe-Okabe's earth pressure theory was not able to evaluate the critical height and the failure zone of the model ground accurately. Based on the model test results, a modified pseudo-static limit equilibrium method incorporating the tensile force along the crack plane was proposed in this study. In the method, the critical height and the failure zone of the cement treated ground were influenced by the strength ratio of the tensile strength to the compressive strength of the treated soil. It was found that the proposed method with a suitable strength ratio was able to predict the tilting test results with fairly high accuracy. Also, the proposed method seemed to be able to reasonably explain the shaking test results if the dynamic response acceleration of the model ground was carefully taken into account. Dynamic active earth pressure of cement treated clay ground was also discussed in which the importance of incorporating the failure pattern was emphasized.
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