Solute transfer during consolidation based on a solid‐fluid‐solute coupling model          下载免费PDF全文

Shun Nomura  Katsuyuki Kawai  Shinya Tachibana  Atsushi Iizuka 《国际地质力学数值与分析法杂志》2018,42(10):1172-1196

The migration of contaminant through soil is usually modeled using the advection‐dispersion equation and assumes that the porous media is stationary without introducing a constitutive equation to represent soil structure. Consequently, time‐dependent deformation induced by soil consolidation or physical remediation is not considered, despite the need to consider these variables during planning for the remediation of contaminated ground, the prediction of contaminated groundwater movement, and the design of engineered landfills. This study focuses on the numerical modeling of solute transfer during consolidation as a first step to resolve some of these issues. We combine a coupling theory‐based mass conservation law for soil‐fluid‐solute phases with finite element modeling to simulate solute transfer during deformation and groundwater convection. We also assessed the sensitivity of solute transfer to the initial boundary conditions. The modeling shows the migration of solute toward the ground surface as a result of ground settlement and the dissipation of excess pore water pressure. The form of solute transport is dependent on the ground conditions, including factors such as the loading schedule, contamination depth, and water content. The results indicate that an understanding of the interaction between coupling phases is essential in predicting solute transfer in ground deformation and could provide an appropriate approach to ground management for soil remediation.  相似文献   

Physical size of tsunamigenic earthquakes of the northwestern Pacific     

Katsuyuki Abe 《Physics of the Earth and Planetary Interiors》1981,27(3):194-205

The new scale M_t of tsunami magnitude is a reliable measure of the seismic moment of a tsunamigenic earthquake as well as the overall strength of a tsunami source. This M_t scale was originally defined by Abe (1979) in terms of maximum tsunami amplitudes at large distances from the source. A method is developed whereby it is possible to determine M_t at small distances on the basis of the regional tsunami data obtained at 30 tide stations in Japan. The relation between log H, maximum amplitude (m) and log Δ, a distance of not less than 100 km away from the source (km) is found to be linear, with a slope close to 1.0. Using three tsunamigenic earthquakes with known moment magnitudes M_w, for calibration, the relation, M_t = log H + log Δ + D, is obtained, where D is 5.80 for single-amplitude (crest or trough) data and 5.55 for double-amplitude (crest-to-trough) data. Using a number of tsunami amplitude data, M_t is assigned to 80 tsunamigenic earthquakes that occurred in the northwestern Pacific, mostly in Japan, during the period from 1894 to 1981. The M_t values are found to be essentially equivalent to M_w for 25 events with known M_w. The 1952 Kamchatka earthquake has the largest M_t, 9.0. Of all the 80 events listed, at least seven unusual earthquakes which generated disproportionately-large tsunamis for their surface-wave magnitude M_s are identified from the relation. From the viewpoint of tsunami hazard reduction, the present results provide a quantitative basis for predicting maximum tsunami amplitudes at a particular site.  相似文献   

Re-Estimation of Annual Anthropogenic Carbon Input from Oyashio into North Pacific Intermediate Water     

Tsuneo Ono  Katsuyuki Sasaki  Ichiro Yasuda 《Journal of Oceanography》2003,59(6):883-891

The annual transport of anthropogenic carbon (C_anth) to the North Pacific Intermediate Water (NPIW) from the Western Subarctic Gyre (WSG) has been re-estimated by using newly estimated Oyashio transport and C_anth concentration, the latter calculated by the recently-established “ΔC*” method with some modifications. Estimated annual C_anth transport through the nearshore Oyashio west of 146°E was 0.020 ± 0.010 GtC y⁻¹, closely approximating the previous estimation based on a 1-D model calibrated with the CFC vertical distribution. The present study, however, found that an additional 0.025 ± 0.010 GtC y⁻¹ of C_anth was transported into NPIW in the region east of 146°E. Total C_anth transport, 0.045 GtC y⁻¹, contributes about 35% of annual C_anth accumulation of the whole temperate North Pacific. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Primary productivity in the offshore Oyashio in the spring and summer 1990     

Akihiro Shiomoto  Katsuyuki Sasaki  Toru Shimoda  Satsuki Matsumura 《Journal of Oceanography》1994,50(2):209-222

Primary productivity was measured byin situ method using¹³C in the offshore Oyashio region in the spring (May) and summer (September) of 1990. Most of the values were within the range of 0.1 to 4 gC 1^–1 h^–1 although a very large value, 7.96 gC l^–1 h^–1, was observed in summer. Most daily primary production fell within the range of 372 to 633 mgC m^–2 d^–1 although a very large value, 2,109 mgC m^–2 d^–1, was observed around the frontal area in summer. Chlorophylla (Chl.a) exceeded 1 g l^–1 in many cases, and the maximum was 4.61 g l^–1 in spring and 7.53 g l^–1 in summer. Most primary productivity per unit Chl.a (photosynthetic assimilation ratio) was within the range of 0.1 to 3 gC gChl.a ^–1 h^–1 although higher values, 3–6 gC gChl.a ^–1 h^–1, were observed where small-size phytoplanktons (<2 m) were dominant. These results were compared with results obtained until now in the Oyashio region. The values beyond the range obtained so far in the offshore region were also observed in this study. Furthermore, it was pointed out that the size composition of phytoplankton community has significant influence on the results of Chl.a and photosynthetic assimilation ratio in the Oyashio region.  相似文献   

Nitrogen circulation in the water column in the Oyashio region with reference to its high productivity     

Yasuo Matsukawa  Katsuyuki Sasaki 《Journal of Oceanography》1991,47(6):265-275

In order to determine quantitatively the reason for the high productivity in the Oyashio Region, which is the southwest part of the Pacific Subarctic Region, the annual-mean vertical circulation of nitrogen in the region was estimated from the vertical profiles of nitrate, dissolved oxygen and salinity, and sediment-trap data by adapting them to the balance equations. Estimates of the upwelling velocity (1.7×10⁻⁵cm sec⁻¹) and the vertical diffusivity (2.1 cm² sec⁻¹) in the abyssal zone and the primary and secondary productivities (44 and 4 mgN m⁻²day⁻¹, respectively) in the euphotic zone were close to those of previous works. The estimated vertical circulation of nitrogen strongly suggested that, since the divergence (5 mgN m⁻²day⁻¹) is caused by the abyssal convergence (6 mgN m⁻²day⁻¹) and the positive precipitation, the local new production (22 mgN m⁻²day⁻¹) necessarily exceeds not only the sinking flux (10 mgN m⁻²day⁻¹) itself but also the sum of the sinking flux and the downward diffusion of dissolved and particulate organic matter (7 mgN m⁻²day⁻¹) produced probably in the euphotic zone. The important roles of the abyssal circulation, the winter convection, and the metabolic activity in the bathyal zone to support the high productivity in the euphotic zone were clarified quantitatively.  相似文献   

Structure and dynamics of water on Li-, Na-, K-, Cs-, H₃O-exchanged muscovite surfaces: A molecular dynamics study     

Hiroshi Sakuma  Katsuyuki Kawamura 《Geochimica et cosmochimica acta》2011,75(1):63-23407

The distribution and dynamics of water molecules and monovalent cations (Li⁺, Na⁺, K⁺, Cs⁺, and H₃O⁺) on muscovite surfaces were investigated by molecular dynamics (MD) simulations. The direct comparison of calculated X-ray reflectivity profiles and electron density profiles with experiments revealed the precise structure at the aqueous monovalent electrolyte solutions/muscovite interface. To explain the experimentally observed electron density profiles for the CsCl solution-muscovite interface, the co-adsorption of Cs⁺ and Cl⁻ ion pairs would be necessary. Two types of inner-sphere complexes and one type of outer-sphere complex were observed for hydrated Li⁺ ions near the muscovite surface. For Na⁺, K⁺, Cs⁺, and H₃O⁺ ions, the inner-sphere complexes were stable on the muscovite surface. The density oscillation of water molecules was observed to approximately 1.5 nm from the muscovite surface. The number of peaks and the locations for the density of water oxygen atoms were almost similar among the water molecules coordinated to Li⁺, Na⁺, K⁺, and H₃O⁺ ions adsorbed on the muscovite surfaces. The water molecules around Cs⁺ ions that were adsorbed to muscovite surfaces seemed to avoid coordinating with Cs⁺ ions on the surface, and the density of water oxygen near the muscovite surface decreased relative to that in a bulk state. There was no significant difference in self-diffusion, viscosity, retention time, and reorientation time of water molecules among different cations adsorbed to muscovite surfaces. These translational and rotational motions of water molecules located at less than 1 nm from the muscovite surfaces were slower than those in a bulk state. A significant difference was observed for the exchange times of water molecules around monovalent cations. The exchange time of water molecules was long around Li⁺ ions and decreased with an increase in the ionic radius.  相似文献   

Theoretical Evaluation of the Mechanical Behavior of Unsaturated Soils     

Michinori Honda  Shintaro Ohno  Atsushi Iizuka  Katsuyuki Kawai  Hideki Ohta 《Geotechnical and Geological Engineering》2011,29(2):171-180

An evaluation method for the mechanical behavior of unsaturated soils is studied in this paper. Although the mechanical behavior of unsaturated soils is complicated, a simple modeling is preferable in practice. This is because the soil properties are not homogeneous and ground data is limited when structures are being designed. In addition, in order to evaluate the reliability of the design, the physical meanings of the parameters applied in the prediction model should be clear. Firstly, the authors study the relationship between compaction curves and compression indexes in the unsaturated state that is used in the proposed constitutive model. Based on the constitutive model, the stress paths for constant volume shear tests are formulated under a constant void ratio condition and the stress paths for undrained shear tests are calculated under a constant water content condition. In the case of unsaturated specimens, the volume of these specimens changes with the shear deformation and the stress paths depend on the initial degree of saturation. The results of the calculation qualitatively describe the test results by considering the changes in effective confining pressure in the undrained condition and the water retention curves.  相似文献   

Laboratory Hydraulic Testing in Unsaturated Soils     

Farimah Masrouri  Kátia V. Bicalho  Katsuyuki Kawai 《Geotechnical and Geological Engineering》2008,26(6):691-704

This paper synthesizes the state-of-the art of the various laboratory testing techniques presently available for measuring the water hydraulic constitutive functions of unsaturated soils. Emphasis is on the laboratory testing techniques for measuring the soil–water retention curves and the water hydraulic conductivity functions of unsaturated soils. The significant recent advances in the investigation of the hydraulic behaviour of unsaturated swelling soils, are also presented. Comprehensive recent references on each measurement method are listed and discussed.  相似文献   

Spectral classification criteria for some early type stars in the UV region/atl>     

M.A. Hamdy  M.S. Abo Elazm  S.M. Saad  H.O. Nafie  H.E. Abdel Baeth 《Astrophysics and Space Science》2002,279(3):203-218

The aim of this paper is to get new critertia for spectral classification of some early type stars which depend on the flux in the UV region λ λ 1500–2500 by carrying out spectrophotometric analysis of observational ultraviolet data of stars obtained by the S2/68 Ultraviolet Sky Survey Telescope (UVSST) aboard the European Space Research Organization (ESRO) Satellite TD1. We have developed these new criteria based on the Intrinsic Ultraviolet Colour Index (IUI), and the Intrinsic Flux Ratio (IFR). Using these quantities we are going to represent the results of spectral classification of 323 early type stars mainly from spectral type B and A. The results of calculations of the Intrinsic Flux Ratios for the stars under investigation together with their Colour Temperatures (Tc) are given. Comparison between our suggested two new criteria with the MK classification system and Cucchairo (1980) classification system was carried out. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Diagnostic study of spring dusty days over the southwest region of the Kingdom of Saudi Arabia     

Awad  Adel M.  Mashat  Abdul-Wahab S.  Salem  Faisal F. Abo 《Arabian Journal of Geosciences》2015,8(4):2265-2282

Arabian Journal of Geosciences - Three classes of dust over the southwest region of the Kingdom of Saudi Arabia were classified based on both the values and distribution of the TOMS Aerosol Index....  相似文献