Prediction of long-term settlement on soft clay using shear wave velocity and damping characteristics     

Mohamad Nor Omar  Colin Peter Abbiss  Mohd. Raihan Taha  Khairul Anuar Mohd. Nayan 《Engineering Geology》2011,(4):259

This paper presents a method of calculating long-term settlement of a loaded pad on soft clay at Klang, Selangor, Malaysia where the soil model is treated as an anelastic material of viscoelastic property. Initially, an elastic shear modulus (G) value from shear wave velocity profiles of the seismic tests from spectral analysis of surface wave (SASW) and continuous surface wave (CSW) tests was obtained. A value of damping (D) at an equivalent elastic strain is then calculated from the hysteresis of the plate load tests corrected to equivalent strain using the Damping–Strain formula. The calculated elastic settlement and its equivalent damping are then used to calculate the long-term settlement by applying the generalised viscoelastic formula. Comparisons to traditional methods of settlement predictions were made and the viscoelastic formula has shown better agreement to the observed settlement. Further modification of the settlement formula is introduced to improve the settlement accuracy to 10%.  相似文献   

A Critical Review on Filter Design Criteria for Dispersive Base Soils     

Amir Hossein Vakili  Mohamad Razip bin Selamat  Parsa Mohajeri  Hossein Moayedi 《Geotechnical and Geological Engineering》2018,36(4):1933-1951

Dispersive soils have become common materials for the construction industry. Highly susceptible to internal erosion and piping, dispersive soils must only be used with specific engineering measure in order to avoid failures that were often catastrophic. In an earth dam, clayey soils are used for the core and sandy materials are used for the filter to retain the eroded core soils and prevent their migration. In the absence of first-rate core material, dispersive soils have been used instead. This paper provides a review of the current knowledge and experiences regarding filtration of core soils, particularly the dispersive ones. The engineering problems associated with the use of dispersive soils are discussed and significant findings from previous studies on protective filters are summarized. It is worthy to note that the current review considers both, the conventional, rather empirical filter design criteria based on particle sizes and the current, quite theoretical state-of-the-art filter design criteria based on constriction sizes, with discussion given on the advantages and disadvantages of both. The information provided by this review should be handy for the study, design, construction, and operation of related geotechnical and geo-environmental projects.  相似文献   

Groundwater and surface-water utilisation using a bank infiltration technique in Malaysia   总被引：1，自引：1，他引：0  

Mohd Khairul Nizar Shamsuddin  Wan Nor Azmin Sulaiman  Saim Suratman  Mohamad Pauzi Zakaria  Kamarudin Samuding 《Hydrogeology Journal》2014,22(3):543-564

Bank infiltration (BI) is one of the solutions to providing raw water for public supply in tropical countries. This study in Malaysia explores the use of BI to supplement a polluted surface-water resource with groundwater. Three major factors were investigated: (1) contribution of surface water through BI to the resulting abstraction, (2) input of local groundwater, and (3) water-quality characteristics of the resulting water supply. A geophysical method was employed to define the subsurface geology and hydrogeology, and isotope techniques were performed to identify the source of groundwater recharge and the interaction between surface water and groundwater. The physicochemical and microbiological parameters of the local surface-water bodies and groundwater were analyzed before and during water abstraction. Extracted water revealed a 5–98 % decrease in turbidity, as well as reductions in HCO₃ ^?, Cl^?, SO₄ ^2?, NO₃ ^?, Ca²⁺, Al³⁺ and As concentrations compared with those of Langat River water. In addition, amounts of E. coli, total coliform and Giardia were significantly reduced (99.9 %). However, water samples from test wells during pumping showed high concentrations of Fe²⁺ and Mn²⁺. Pumping test results indicate that the two wells used in the study were able to sustain yields.  相似文献   

A knowledge-driven GIS modeling technique for groundwater potential mapping at the Upper Langat Basin, Malaysia   总被引：3，自引：1，他引：2  

Mohamad Abd Manap  Wan Nor Azmin Sulaiman  Mohammad Firuz Ramli  Biswajeet Pradhan  Noraini Surip 《Arabian Journal of Geosciences》2013,6(5):1621-1637

The aim of this paper is to use a knowledge-driven expert-based geographical information system (GIS) model coupling with remote-sensing-derived parameters for groundwater potential mapping in an area of the Upper Langat Basin, Malaysia. In this study, nine groundwater storage controlling parameters that affect groundwater occurrences are derived from remotely sensed imagery, available maps, and associated databases. Those parameters are: lithology, slope, lineament, land use, soil, rainfall, drainage density, elevation, and geomorphology. Then the parameter layers were integrated and modeled using a knowledge-driven GIS of weighted linear combination. The weightage and score for each parameter and their classes are based on the Malaysian groundwater expert opinion survey. The predicted groundwater potential map was classified into four distinct zones based on the classification scheme designed by Department of Minerals and Geoscience Malaysia (JMG). The results showed that about 17% of the study area falls under low-potential zone, with 66% on moderate-potential zone, 15% with high-potential zone, and only 0.45% falls under very-high-potential zone. The results obtained in this study were validated with the groundwater borehole wells data compiled by the JMG and showed 76% of prediction accuracy. In addition statistical analysis indicated that hard rock dominant of the study area is controlled by secondary porosity such as distance from lineament and density of lineament. There are high correlations between area percentage of predicted groundwater potential zones and groundwater well yield. Results obtained from this study can be useful for future planning of groundwater exploration, planning and development by related agencies in Malaysia which provide a rapid method and reduce cost as well as less time consuming. The results may be also transferable to other areas of similar hydrological characteristics.  相似文献   

Hisslers observed during daytime in a low latitude ground station     

Krishna Kumar Singh  Ravindra Pratap Patel  Balraj Kumar  Mohamad Altaf  Prince Ahmad Ganai  Abhay Kumar Singh  Ram Pal Singh  Lalmani 《Acta Geophysica》2009,57(2):536-547

The observation of hisslers during daytime at low latitude station Jammu, India, is reported. The hissler elements are quasi-periodic falling tones observed during the period of hiss activity and appear in minutelong sequences with average spacing between individual elements of the order of 0.15 s. Hissler elements exhibit almost no dispersion and no complex internal structure in slope and intensity, and successive hissler elements do not overlap in time. It seems that the reported hisslers might have propagated in prolongitudinal mode.  相似文献   

The role of hydrologic information in reservoir operation – Learning from historical releases     

Mohamad I. Hejazi  Ximing Cai  Benjamin L. Ruddell 《Advances in water resources》2008,31(12):1636-1650

Closing the gap between theoretical reservoir operation and the real-world implementation remains a challenge in contemporary reservoir operations. Past research has focused on optimization algorithms and establishing optimal policies for reservoir operations. In this study, we attempt to understand operators’ release decisions by investigating historical release data from 79 reservoirs in California and the Great Plains, using a data-mining approach. The 79 reservoirs are classified by hydrological regions, intra-annual seasons, average annual precipitation (climate), ratio of maximum reservoir capacity to average annual inflow (size ratio), hydrologic uncertainty associated with inflows, and reservoirs’ main usage. We use information theory – specifically, mutual information – to measure the quality of inference between a set of classic indicators and observed releases at the monthly and weekly timescales. Several general trends are found to explain which sources of hydrologic information dictate reservoir release decisions under different conditions. Current inflow is the most important indicator during wet seasons, while previous releases are more relevant during dry seasons and in weekly data (as compared with monthly data). Inflow forecasting is the least important indicator in release decision making, but its importance increases linearly with hydrologic uncertainty and decreases logarithmically with reservoir size. No single hydrologic indicator is dominant across all reservoirs in either of the two regions.  相似文献   

Architects and planners approaches to urban form and design in the Toronto region: A comparative analysis     

Mohamad Kashef 《Geoforum》2008,39(1):414-437

This study compares architectural and planning approaches to urban form and design within a North American context. It presents a critical assessment of the results of semi-structured, in-depth interviews with a group of highly experienced architects, landscape architects, and planners from the Greater Toronto Region. Dialogues with practitioners revealed a growing intellectual divide in regard to understanding urban form and design issues. Planners portrayed the urban form as a product of social and economic forces or a backdrop for civic institutions, private development initiatives, and public action. Architects and landscape architects, on the other hand, emphasized the importance of built configurations and spatial relations in shaping economic, social, and cultural patterns. With such a polarized perspective of urban development processes, each group of practitioners proposed different and somewhat contradictory visions for the future of North American built forms. This study develops an understanding of theoretical and pragmatic concerns within design professions (architecture/landscape architecture) and social science professions (planning at large) that hamper the development of integrative urban design visions. It extends an interdisciplinary understanding of built environments and the forces that shape them and paves the way for more in-depth studies aimed at creating more integrative urban design theories and development strategies.  相似文献   

A superb modified new adsorbent, <Emphasis Type="Italic">Artocarpus odoratissimus</Emphasis> leaves,for removal of cationic methyl violet 2B dye     

L. B. L. Lim  N. Priyantha  N. A. H. Mohamad Zaidi 《Environmental Earth Sciences》2016,75(16):1179

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The effect of climate and land use change on flow duration in the Maryland Piedmont region     

Mohamad I. Hejazi  Glenn E. Moglen 《水文研究》2008,22(24):4710-4722

This paper describes the use of a continuous streamflow model to examine the effects of climate and land use change on flow duration in six urbanizing watersheds in the Maryland Piedmont region. The hydrologic model is coupled with an optimization routine to achieve an agreement between observed and simulated streamflow. Future predictions are made for three scenarios: future climate change, land use change, and jointly varying climate and land use. Future climate is modelled using precipitation and temperature predictions for the Canadian Climate Centre (CCC) and Hadley climate models. Results show that a significant increase in temperature under the CCC climate predictions produces a decreasing trend in low flows. A significant increasing trend in precipitation under the Hadley climate predictions produces an increasing trend in peak flows. Land use change by itself, as simulated by an additional 10% increase in imperviousness (from 20·5 to 30·5%), produces no significant changes in the simulated flow durations. However, coupling the effects of land use change with climate change leads to more significant decreasing trends in low flows under the CCC climate predictions and more significant increasing trends in peak flows under Hadley climate predictions than when climate change alone is employed. These findings indicate that combined land use and climate change can result in more significant hydrologic change than either driver acting alone. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Application of probabilistic-based frequency ratio model in groundwater potential mapping using remote sensing data and GIS   总被引：3，自引：1，他引：2  

Mohamad Abd Manap  Haleh Nampak  Biswajeet Pradhan  Saro Lee  Wan Nor Azmin Sulaiman  Mohammad Firuz Ramli 《Arabian Journal of Geosciences》2014,7(2):711-724

The main goal of this study is to investigate the application of the probabilistic-based frequency ratio (FR) model in groundwater potential mapping at Langat basin in Malaysia using geographical information system. So far, the approach of probabilistic frequency ratio model has not yet been used to delineate groundwater potential in Malaysia. Moreover, this study includes the analysis of the spatial relationships between groundwater yield and various hydrological conditioning factors such as elevation, slope, curvature, river, lineament, geology, soil, and land use for this region. Eight groundwater-related factors were collected and extracted from topographic data, geological data, satellite imagery, and published maps. About 68 groundwater data with high potential yield values of ≥11 m³/h were randomly selected using statistical software of SPSS. Then, the groundwater data were randomly split into a training dataset 70 % (48 borehole data) for training the model and the remaining 30 % (20 borehole data) was used for validation purpose. Finally, the frequency ratio coefficients of the hydrological factors were used to generate the groundwater potential map. The validation dataset which was not used during the FR modeling process was used to validate the groundwater potential map using the prediction rate method. The validation results showed that the area under the curve for frequency model is 84.78 %. As far as the performance of the FR approach is concerned, the results appeared to be quite satisfactory, i.e., the zones determined on the map being zones of relative groundwater potential. This information could be used by government agencies as well as private sectors as a guide for groundwater exploration and assessment in Malaysia.  相似文献