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61.
Mohamad Tarmizi Mohamad Zulkifley Ng Tham Fatt Wan Hasiah Abdullah John Kuna Raj S. Paramanathan Param Roslan Hashim Muhammad Aqeel Ashraf 《Central European Journal of Geosciences》2013,5(2):285-314
Petrographic studies indicate that lateral variations in the decomposition levels of peat are associated with the predominantly occurring peat macerals. Source Rock Analyzer (SRA) results indicate lateral variation in peat organic matter types from type II to III and back again to type II, occurring laterally within the top 0-m to 0.5-m layer at the basin margin to the midsection and further towards the near-center areas of the peat dome. This variation is most likely caused by a combination of factors: (a) Horizontal zonation and lateral variation of the dominant species of plant assemblages (b) Fibric (marginal) peats and hemic to sapric peats associated with type II organic matter (kerogen). Sample organic matter (coal-equivalent kerogen) typing indicates that the relative abundance of phytoclasts and palynomorphs generally supports the organic matter classification obtained by the SRA method. Lateral variations in the peat organic matter types may support the lateral vegetation variation concept. The classification of peat organic matter types (interpreted from visual analyses of palynological slides) occurring from the basin periphery to the mid-section and further towards the basin center yields organic matter of type II to type III and mixed types II to III (coal kerogen-equivalent), respectively. 相似文献
62.
A new procedure based on the approximation to the total normal pressure along the slip surface is developed to compute the factor of safety of slopes for slip surfaces of all shapes. By taking the whole sliding body, instead of an individual slice, as the loaded object, all the equilibrium equations are formulated according to the three‐moment equilibrium conditions rather than the two force equilibrium conditions and one‐moment equilibrium condition. The system of nonlinear equations deduced in this way is well‐scaled and enjoys excellent numerical properties such as the existence of solution with a positive factor of safety, a nearly unlimited scope of convergence and a rapid convergence rate associated with the Newton method. In the case of ?u =0—the situation where no drainage and no consolidation are involved, furthermore, the system has a unique solution and the factor of safety has an explicit expression. Some typical examples are analyzed to demonstrate the numerical properties of the proposed procedure. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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This work studied the influence of meteorological conditions on particulate polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Higashi Hiroshima, Japan. The seasonal variation of particulate PAHs was also covered. It was found that ambient temperature, solar intensity and weekly rainfall had significant influence on the particulate PAH concentration based on correlation studies. Correlation of particulate PAHs with ambient temperature, solar intensity, weekly rainfall, wind speed and humidity was studied by using Pearson correlation analysis. Particulate PAHs had a strong negative correlation with ambient temperature and solar intensity. A moderate negative correlation with weekly rainfall was also observed. There was no significant correlation between particulate PAHs with wind speed as well as humidity. Besides, particulate PAHs were found to have significant positive correlation with sulfur dioxide and nitrogen dioxide while having a moderate negative correlation with ozone. The particulate PAHs in Higashi Hiroshima exerted distinct seasonal variation with a higher concentration in winter and lower concentration in summer. When compared among PAHs with different numbers of aromatic rings; 5-ring PAHs was found to exert the most distinct seasonal variation. The contribution of carcinogenic PAHs to total particulate PAH concentration was fairly constant at about 50% throughout the year. 相似文献
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67.
Analysis of shield tunnel 总被引：1，自引：0，他引：1
This paper proposes a two‐dimensional finite element model for the analysis of shield tunnels by taking into account the construction process which is divided into four stages. The soil is assumed to behave as an elasto‐plastic medium whereas the shield is simulated by beam–joint discontinuous model in which curved beam elements and joint elements are used to model the segments and joints, respectively. As grout is usually injected to fill the gap between the lining and the soil, the property parameters of the grout are chosen in such a way that they can reflect the state of the grout at each stage. Furthermore, the contact condition between the soil and lining will change with the construction stage, and therefore, different stress‐releasing coefficients are used to account for the changes. To assess the accuracy that can be attained by the method in solving practical problems, the shield tunnelling in the No. 7 Subway Line Project in Osaka, Japan, is used as a case history for our study. The numerical results are compared with those measured in the field. The results presented in the paper show that the proposed numerical procedure can be used to effectively estimate the deformation, stresses and moments experienced by the surrounding soils and the concrete lining segments. The analysis and method presented in this paper can be considered to be useful for other subway construction projects involving shield tunnelling in soft soils. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
68.
A time domain boundary element in a cylindrical co-ordinate system is developed for the analysis of wave propagation in a layered half-space. The field quantities (displacements and tractions) are expressed as products of Fourier series in the circumferential direction and as linear polynomials in the other spatial directions. An integral equation is written for each layer as an independent domain, and these equations are then assembled into a general equation by virtue of compatibility and equilibrium conditions between the interfaces. Examples of three-dimensional wave propagation in the layered half-spaces due to various forms of surface and inner-domain excitations are reported to demonstrate the accuracy and versatility of the method. 相似文献
69.
A time domain boundary element in a cylindrical coordinate system is developed for the analysis of wave propagation in a half space. The integral formulation is based on Graffi's dynamic reciprocal theorem and Stokes' fundamental solutions. The field quantities (displacements and tractions) are expressed as products of Fourier series in the tangential direction and linear polynomials in the other spatial directions. Gaussian integration is used to integrate the non-singular parts of the integral equations, whereas the integration of the singular components, which are either of order 1/r or 1/r2, is handled by special numerical schemes. In the time marching aspect, the field quantities are assumed to vary linearly in the temporal direction as well. Examples for wave propagation due to various forms of surface excitations are reported to demonstrate the accuracy of the method. 相似文献
70.
This paper proposes a solution for single pile embedded in layered soil. The soil is divided into a number of infinite layers and the displacement shape functions of the layer are given as a product of piecewise polynomial expansion along the depth and series expansions in radial as well as tangential directions. The pile is divided into a number of solid bar elements along its length and it deforms as a rigid section in the horizontal plane. The interaction between the two components can be treated in the standard manner. Typical examples of a single pile are presented to demonstrate the versatility and accuracy of the method. 相似文献