Estimation of static earth pressures for a sloping cohesive backfill using extended Rankine theory with a composite log-spiral failure surface     

Xu  Shi-Yu  Lawal  Abiodun Ismail  Shamsabadi  Anoosh  Taciroglu  Ertugrul 《Acta Geotechnica》2019,14(2):579-594

The Rankine earth pressure theory is extended herein to an inclined c–? backfill. An analytical approach is then proposed to compute the static passive and active lateral earth pressures for a sloping cohesive backfill retained by a vertical wall, with the presence of wall–soil interface adhesion. The proposed method is based on a limit equilibrium analysis coupled with the method of slices wherein the assumed profile of the backfill failure surface is a composite of log-spiral and linear segments. The geometry of the failure surface is determined using the stress states of the soil at the two boundaries of the mobilized soil mass. The resultant lateral earth thrust, the point of application, and the induced moment on the wall are computed considering global and local equilibrium of forces and moments. Results of the proposed approach are compared with those predicted by a number of analytical models currently adopted in the design practice for various combinations of soil’s frictional angles, wall–soil interface frictional angles, inclined angles of backfill and soil cohesions. The predicted results are also verified against those obtained from finite element analyses for several scenarios under the passive condition. It is found that the magnitude of earth thrust increases with the backfill inclination angle under both the passive and active conditions.

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Dilatancy and the Strength of Rocks containing Pore Water under Undrained Conditions     

I. A. H. Ismail  S. A. F. Murrell 《Geophysical Journal International》1976,44(1):107-134

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Cd and Zn concentrations in the straits of Malacca and intertidal sediments of the west coast of Peninsular Malaysia   总被引：1，自引：0，他引：1  

Yap CK  Ismail A  Tan SG 《Marine pollution bulletin》2003,46(10):1349-1353

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Hydrogeochemical modeling of the shallow groundwater in the northern Jordan Valley   总被引：4，自引：0，他引：4  

N.?Abu-JaberEmail author  M.?Ismail 《Environmental Geology》2003,44(4):391-399

The reasons for the rapid degradation and salination of the shallow aquifer in the northern Jordan Valley were investigated. Shallow groundwater, surface water and thermal water were sampled from the study area for this purpose. The geochemical mass-balance technique was used to quantify the contribution of different sources, geochemical processes and rock types to the final water composition, applying the NETPATH software package. The isotopic compositions of the water were also investigated. The results suggest three potential recharge sources: the Yarmouk River, the Jordan River, and the Mukheibah thermal water. Evaporation significantly contributes to the current chemistry of the shallow water, as is indicated by the geochemical models and the isotopic results. Tritium analyses indicate that the water is clearly new (less than 50 years). The relatively high values of nitrate in some wells may be of anthropogenic origin.  相似文献   

Correlation functions of rainfall field and their application in network design in the tropics     

D. A. Mooley  P. M. Mohamed Ismail 《Pure and Applied Geophysics》1982,120(2):249-260

The study examines the correlation function of tropical monsoon rainfall on monthly, seasonal and annual time scales and obtains the relationship between this function and the distance. The area selected for study is Vidarbha with a fairly dense network of rain gauges. Vidarbha is a meteorological sub-division of the state of Maharashtra in India. Utilizing the relationship between the correlation function of the rainfall field and the distance, the errors of optimum interpolation of rainfall at a point have been computed by applying the method of optimum interpolation byGandin (1970). Relationships between the errors of interpolation and distance have been evaluated and from this the maximum spacing allowed between rain gauges for a specified tolerable error in interpolation has been estimated for each of the periods.  相似文献   

Temporal variations of polar cap 0I 5577-Å airglow     

S. Ismail  L.L. Cogger 《Planetary and Space Science》1982,30(9):865-873

Limb observations of the E-region 0I 5577-Å airglow in the polar caps were obtained during 1971 and 1972 from the ISIS-2 satellite. In the southern polar cap the emission rate decreased to a broad minimum of 100 R near solstice, then increased later in the winter. In the northern polar cap a maximum was observed in November. In addition to large daily variations, there were enhancements that lasted several weeks. From a correlation analysis using both satellite data supplemented by the more extensive data base of Mullen et al. (1977,Planet. Space Sci.25, 23) and stratospheric temperatures, it is clear that stratospheric warmings result in polar cap airglow enhancements. The most plausible cause of these airglow enhancements appears to be increased meridional transport of atomic oxygen into the polar cap.  相似文献   

Upper mantle anisotropy beneath the African IRIS and Geoscope stations     

Guilhem Barruol  Walid Ben Ismail 《Geophysical Journal International》2001,146(2):549-561

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Radiative surface temperature and convective flux calculation over crop canopies     

Jean-Paul Lhomme  Nader Katerji  Alain Perrier  Jean-Michel Bertolini 《Boundary-Layer Meteorology》1988,43(4):383-392

The analysis presented in this paper aims at a better understanding of the potential role of radiative temperature, as measured by a radiometer over crops, in sensible heat flux calculation. Defining radiative temperature as the mean temperature of the surfaces viewed by the radiometer (leaves and soil surface) and assuming that an Ohm's law type formula can be used to express sensible heat flux as a function of the difference between air temperature and radiative temperature, the aerodynamic resistance which divides this temperature difference has been analytically defined. The parameters which appear in the resistance expression depend essentially on wind velocity and canopy structure but also on the inclination angle of the radiometer. Finally an experimental verification is presented with data obtained over a potato crop.  相似文献   

Optimum design of single-frequency dynamic dampers     

Nader D. Ebrahimi 《地震工程与结构动力学》1988,16(4):541-553

The problem of damping the vibration amplitude of machines and structures has considerable practical importance. This paper discusses the design of optimum vibration absorbers for linear damped systems operating at a certain excitation frequency. The problem is first formulated as a mathematical programming scheme. The systematic design discussed in this paper has significant advantages for those vibratory systems run primarily at a specific frequency.  相似文献   

Afghan conflicts and Soviet intervention -perception,reality and resolution     

Mohammad Ismail  Siddiqi 《GeoJournal》1989,18(2):123-132

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