JaLCDOI 10.18926/fest/11639
FullText URL 001_193_198.pdf
Author Shimada, Kiyoshi| Nishimura, Sin-ichi| Fujii, Hiroaki|
Abstract This paper presents a new method for prediction of consolidation settlements of soft grounds. The method is based on the theoretical result which shows that the settlement velocity of soft grounds non-improved or improved with sand drains decreases exponentially with time. Final settlements can be easily derived from the regression analysis for the relationship between the elapsed time and the observed settlement velocity. The method has advantages of its simplicity and capability to give the satisfactorily good estimate of the consolidation settlements, and also the support of the theoretical background.
Keywords consolidation settlement prediction soft ground sand drains one-dimensional consolidation
Publication Title 岡山大学環境理工学部研究報告
Published Date 1996-03
Volume volume1
Issue issue1
Start Page 193
End Page 198
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002314033
JaLCDOI 10.18926/fest/11636
FullText URL 001_181_192.pdf
Author Fujii, Hiroaki| Narita, Mutsuya| Cheng Chin Thai| Shimada, Kiyoshi| Nishimura, Shinichi| Ofori Emanual|
Abstract This paper describes the prediction of seepage in the impervious zones of six embankment dams by seepage analysis. In addition, by making use of the available monitored pore water pressure data of the first filling of reservoir, back analysis was carried out to estimate the best fit seepage parameters. The estimated parameters were used for further prediction of pore water pressures in subsequent monitored durations with reasonable accuracy. The accuracy of prediction was evaluated quantitatively by the prediction difference and error index. The results show that the error indices in the upstream sides of the impervious zones are smaller than those in the downstream sides.
Keywords Unsaturated soils fill dams pore water pressure back analysis FEM
Publication Title 岡山大学環境理工学部研究報告
Published Date 1996-03
Volume volume1
Issue issue1
Start Page 181
End Page 192
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313591
JaLCDOI 10.18926/fest/11612
FullText URL 002_107_120.pdf
Author Fujii, Hiroaki| Ofori Emmanuel| Shimada, Kiyoshi| Nishimura, Shin-ichi|
Abstract This paper discusses a numerical model that can be used to optimize the installation in a zoned type and a homogeneous type fill dam. Before installation in a real dam to evaluate dam behavior, numerical model described in this paper is carried out on a prototype dam to check the optimum installation, using cross arm measurements. Three cross arm installations at the upstream, the core and downstream to measure displacements are considered. The installation options considered are three cross arm combinations for best installation to verify the safety of dams and to reduce cost. Finite element method is used for generating the displecement field in a linear elastic numerical model. The generated data is used as an input data in the back analysis to check the adequacy of each installation option.
Publication Title 岡山大学環境理工学部研究報告
Published Date 1997-01-10
Volume volume2
Issue issue1
Start Page 107
End Page 120
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313925
JaLCDOI 10.18926/fest/11591
Title Alternative Evaluation of Liquefaction Resistance by In-situ Testing and Its Application to Reliability Design
FullText URL 005_145_151.pdf
Author Nishimura, Shin-ichi| Shimizu, Hideyoshi| Fujii, Hiroaki| Shimada, Kiyoshi|
Abstract A calculation method of probability of liquefaction is proposed in this paper. The spatial variability of soil parameters for the dynamic shear strength, i.e., N-values, median grain size, fines contents, and the statistical characteristics of the earthquake frequency are considered in the analysis. The standard penetration test (SPT) is convenient to estimate the spatial variability of the dynamic shear strength and mainly used in this study. Furthermore the determination of dynamic shear strength based on Swedish weight Sounding test also introduced here, because it is the simpler test than SPT. While the statistical model of the earthquake frequency is determined based on the record of historical earthquakes. Using this method the probability of liquefaction is calculated. The sand compaction pile method is considered for the ground improvement against the liquefaction. Finally, the relationship between the sand replacement rate and the probability of liquefaction is clarified.
Keywords probability of liquefaction reliability design spatial variability of soil parameters statistical model of earthquake frequency dynamic shear strength
Publication Title 岡山大学環境理工学部研究報告
Published Date 2000-02-29
Volume volume5
Issue issue1
Start Page 145
End Page 151
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002314022
JaLCDOI 10.18926/fest/11569
FullText URL 005_071_079.pdf
Author Jafar Ali Mohammad| Takeshita, Yuji| Fujii, Hiroaki|
Abstract In-situ determination of fundamental hydraulic parameters like variably saturated hydraulic conductivity (K(FS)) and the matric flux potential (Φ(m)) provides a foundation from which several other unsaturated soil parameters can be estimated, namely the Alpha (α*) parameter. This Alpha parameter is the one of the components of 3D unsaturated flow in vadose zone and its value is the measure of the capillary component of unsaturated flow pattern. Here an in-situ technique, Pressure Infiltrometer is introduced to record the steady flow rate applying a constant positive head on an unsaturated soil surface. The aim of this paper is to check the shape factor of 3D flow geometry and to find out its sensitivity on other unsaturated hydraulic parameters and to find out the influence of Alpha parameters on the results of the in-situ estimation of field-saturated hydraulic conductivity.
Keywords Field-saturated hydraulic conductivity Matric flux potential Alpha parameter Shape factor In-situ test
Publication Title 岡山大学環境理工学部研究報告
Published Date 2000-02-29
Volume volume5
Issue issue1
Start Page 71
End Page 79
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313869
JaLCDOI 10.18926/fest/11539
Title Alternative One-dimensional Compression Tests of Sludge Cake from Dredged Sludge
FullText URL 006_085_097.pdf
Author Wakitani, Yoshiaki| Fujii, Hiroaki| Nishimura, Shin-ichi| Inoue, Takashi|
Abstract One-dimensional compression tests were performed to investigate compression characteristics of sludge cake used as a construction material. The sludge cake is dewatering product of dredged sludge from the bottom of a lake. The test results show following compression characteristics. (1) For the undisturbed samples, e-log p curves show compressibility of overconsolidated clay ordinatily observed. (2) For the disturbed samples, there observed compressibility close to that of ordinary normally consolidated clay. (3) For the recompressed samples, there observed two turning points on e-log p curve. The compression presures(p(c1) and p(c2)) at those points for the unsubmerged tests have a linear correlation with the recompression pressure(p(s)). The submerged tests give very small values of p(c1) and p(c2) compared with the case of unsubmerged test. (4) For the recompressed samples, the first compression index(C(c1)) after p(c) has a linear correlation with the initial void ratio(e(0)), and the second compression index(C(c2)) shows almost constant value.
Keywords sludge cake one-dimensional compression test e~log p curve compression index void ratio
Publication Title 岡山大学環境理工学部研究報告
Published Date 2001-02-28
Volume volume6
Issue issue1
Start Page 85
End Page 97
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313853
JaLCDOI 10.18926/fest/11528
Title Alternative Damage factors analysis for small embankment dams due to the Hyogoken-Nambu earthquake special to Hokudan Town
FullText URL 007_055_074.pdf
Author Fujii, Hiroaki| Kunimasa, Kana| Nanba, Akiyo| Yokomizo, Takayuki| Nishimura, Shin-ichi| Shimada, Kiyoshi| Hori, Toshio| Nishiyama, Tatsuro| Wakitani, Yoshiaki|
Abstract This study was performed to clarify which factors affected damage to take-ike (small embankment dams for irrigation in Japanese) of Hokudan Town on Awaji Island in western Japan due to Hyogoken-Nambu earthquake. Multivariate and ordinary statistical analysis were carried out using documentary data (181 damaged and 328 undamaged dams), and ordinary one was done for the results investigated in situ. The model for the multivariate analysis was created with 13 items and 94 categories for 4 groups (Location, Geology Structure, and History of Dam). As a result, the factors causing to damage for dam are (1) the nearest fault (Nojima, Mizukoshi and D2), (2) embankment volume (the larger the more), (3) angle of crest axis to epicenter (diagonal and normal), (4) distance to the nearest fault (less than 500 m), (5) distance to the epicenter (8 to 14 km which almost agree to the location of seismic intensity 7 JMA), (6) play view of dam axis (3 or 4 axes), (7) angle of crest axis to nearest fault (diagonal and normal), (8) elevation of dam site (over 100 m), (9) surface geology of dam site (non-cohesive soil), (10) era of construction (prior to 1891), and (11) soil properties of embankment (constructed of sand, smaller penetration resistance).
Keywords Earth dam earthquake damage site investigation statistical analysis case study
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 55
End Page 74
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002314039
Author Nishimura, Shin-ichi| Fujii, Hiroaki|
Published Date 1994
Publication Title 岡山大学農学部学術報告
Volume volume83
Issue issue1
Content Type Departmental Bulletin Paper
Author Fujii, Hiroaki| Watanabe, Tadashi|
Published Date 1973
Publication Title 岡山大学農学部学術報告
Volume volume41
Issue issue1
Content Type Departmental Bulletin Paper