Fractional-calculus-based formulation of the fractured wells in fractal radial composite reservoirs     

Kambiz Razminia  Abolhassan Razminia  Abdolnabi Hashemi 《Environmental Earth Sciences》2016,75(22):1436

  相似文献   

Relationships between geological formations and groundwater chemistry and their effects on the concrete lining of tunnels (case study: Tabriz metro line 2)     

Mohammad Hossein Ghobadi  Mahnaz Firuzi  Ebrahim Asghari-Kaljahi 《Environmental Earth Sciences》2016,75(12):987

  相似文献   

Effect of Natural Zeolite and Cement Additive on the Strength of Sand   总被引：1，自引：1，他引：0  

Hossein Mola-Abasi  Behrouz Kordtabar  Afshin Kordnaeij 《Geotechnical and Geological Engineering》2016,34(5):1539-1551

It is widely known and well emphasized that the cemented sand is one of economic and environmental topics in soil stabilization. In some instances, a blend of sand, cement and other materials such as fiber, glass, nano particle and zeolite can commercially be available and effectively used in soil stabilization especially in road construction. In regard to zeolite, its influence and effectiveness on the properties of cemented sands systems has not been completely explored. Hence, in this study, based on an experimental program, it has been tried to investigate the potential of a zeolite stabilizer known as additive material to improve the properties of cemented sands. A total number of 216 unconfined compression tests were carried out on cured samples in 7, 28 and 90 days. Results show unconfined compression strength and failure properties improvements of cement sand specimens when cement replaced by zeolite at optimum proportions of 30 % after 28 days due to pozzolanic reaction. The rate of strength improvement is approximately 20–78 and 20–60 % for 28 and 90 days curing times respectively. The efficiency of using zeolite has been enhanced by increasing the cement content and porosity of the compacted mixture. The replacement of cement by natural zeolite led to an increase of the pH after 14 days. Chemical oxygen demand (COD) tests demonstrate that the materials with the zeolite mixture reveal stronger adsorptive capacity of COD in compare to cemented mixture. Scanning electron microscope images show that adding zeolite in cemented sand changes the microstructure (filling large porosity and pozzolanic reaction) that results in increasing strength.  相似文献   

Application of the Christensen Failure Criterion to Intact Rock     

Hossein Rafiei Renani  C. Derek Martin  Evert Hoek 《Geotechnical and Geological Engineering》2016,34(1):297-312

The Christensen criterion, originally introduced in materials science, has a simple mathematical form and uniaxial tensile and compressive strength as the only parameters, making it an attractive candidate for rock engineering purposes. In this study, the applicability of the criterion to rock materials is examined. Explicit equations for application of the criterion under biaxial, triaxial compression, triaxial extension, and polyaxial states of stresses are derived. A comprehensive strength data set including the results of tests on synthetic rock, chert dyke, Carrara marble and Westerly granite is utilized to examine the accuracy of the Christensen criterion to the failure of rock material. The two surprising findings about the Christensen criterion are the zero values of tensile strength and the very low slopes of the failure envelope obtained from fitting analyses for chert dyke and Westerly granite. It is shown that the two problems are interrelated and the values of tensile strength tend to zero to produce higher slopes. It is then mathematically proven that the maximum initial slope of the Christensen failure envelope is limited to 4 in triaxial compression and 2.5 in triaxial extension which is considerably lower than the slope of experimental data. The accuracy of the Christensen criterion was found to be significantly lower than the well-established Hoek–Brown criterion. The circular π-plane representations and brittle-to-ductile transition limits from the Christensen criterion are also inconsistent with the observed behavior of rocks.  相似文献   

Simulation of rainfall-runoff process using an artificial neural network (ANN) and field plots data     

Gholami  Vahid  Sahour  Hossein 《Theoretical and Applied Climatology》2022,147(1-2):87-98

Theoretical and Applied Climatology - Rainfall-runoff modeling is necessary for many hydrological studies, such as estimating peak discharges and designing hydraulic structures. The intensity and...  相似文献   

Pressuremeter Modulus and Limit Pressure of Clayey Soils Using <Emphasis Type="Italic">GMDH</Emphasis>-Type Neural Network and Genetic Algorithms     

Reza Ziaie Moayed  Afshin Kordnaeij  Hossein Mola-Abasi 《Geotechnical and Geological Engineering》2018,36(1):165-178

Pressuremeter modulus (\(E_{M}\)) and limit pressure (\(P_{L}\)) are used for the calculation of the settlement and bearing capacity of foundation respectively. As the determination of these parameters from pressuremeter test (PMT) is relatively time-consuming and expensive, various empirical correlations have been proposed to correlate the \(E_{M}\) and \(P_{L}\) to other soil parameters. For the existing equations are incapable of estimating these PMT parameters well, in present research group method of data handling type neural network is used to estimate the \(E_{M}\) and \(P_{L}\) of clayey soils. The \(E_{M}\) and \(P_{L}\) were modeled as a function of three variables including the moisture content (\(\omega\)), plasticity index and corrected SPT blow counts (\(N_{60}\)). A database containing 51 data sets have been used for training and testing of the models. The performances of proposed models are compared with those of existing empirical equations. The results demonstrate that appreciable improvement with respect to the other correlations has been achieved. At the end, sensitivity analysis of the obtained models has been performed to study the influence of input parameters on model outputs and shows that the \(N_{60}\) is the most influential parameter on the PMT parameters.  相似文献   

Geology and Mineral Chemistry of Gold Mineralization in Mirge‐Naqshineh Occurrence (Saqez,NW Iran): Implications for Transportation and Precipitation of Gold     

Golale ASGHARI  Samad ALIPOUR  Hossein AZIZI  Hassan MIRNEJAD 《《地质学报》英文版》2018,92(1):210-224

The Mirge-Naqshineh gold district is situated at northwest of Iran with a NW-trending brittleductile shear zone. It is hosted by Precambrian meta-sedimentary and meta-volcanic units traversed by mineralized quartz veins. In terms of cross-cutting relationships and sulfide content three types of quartz veins are identified in the region. Among those, parallel to bedding quartz vein(type Ⅰ) is the main host for gold mineralization. Gold is found in three different forms: 1) submicrometer-size inclusions of gold in arsenian pyrite, 2) as electrum and 3) in the crystal lattice of sulfides(pyrite, galena and chalcopyrite). Six types of pyrite(Py1-Py6) were identified in this ore reserve. Py3 coexists with arsenopyrite and contains the greatest As-Au concentrations. There is a negative correlation between the As and S contents in Py2 and Py3, implying the substitution of sulfur by arsenic. Pyrites and mineralized quartz veins were formed via metamorphic-hydrothermal fluid and reflect the gold-transportation as Au(HS)_2~- under reducing and acidic conditions. The gold precipitation mainly controlled by crystallization of arsenian pyrite during fluid/rock interactions and variation of fO_2. The volcanic host rock has played an important role in gold concentration, as Py3 in this rock contains inclusion of gold particles, but gold is within the lattice of pyrite in phyllite or other units.  相似文献   

Surface irrigation performance of date palms under water scarcity in arid irrigated lands     

Zied Haj-Amor  Henk Ritzema  Hossein Hashemi  Salem Bouri 《Arabian Journal of Geosciences》2018,11(2):27

In this paper, a study on the performance of surface irrigation of date palms in a Tunisian arid area (Douz oasis) is presented. The study is conducted in 16 plots with various sizes and soil textures over a 4-year period (2012–2015). In the first step, an assessment of total water requirements of the date palms is carried out. Then, the surface irrigation performance is analyzed using three indicators, i.e., the relative water supply (RWS) indicator, the uniformity index of water distribution (D _U ), and the water application efficiency (E _a ). Finally, the irrigation management problems are identified. The results indicate that in the arid Tunisian Saharan oases, the soil texture, plot size, and farmers’ practices (especially irrigation duration) have significant effects on surface irrigation performance. The average annual net irrigation requirements of date palms are about 2400 mm. The RWS increases from 1.8 in the smaller plots (0.5 ha) to 3.6 in the largest plots (2.5 ha), implying that the increase in the plot size requires an excessive water supply. D _U decreases from 80.7 in the 0.5 ha plots to 65.4 in the 2.5 ha plots; however, no significant difference in the E _a is observed. The results show that the soil texture has no influence on the RWS and D _U , but the E _a is significantly higher in the loamy-sand soils (46.7%) compared to the sandy soils (36.3%). Overall, RWS indicator is higher than 1 (RWS?=?2.6) implying excessive irrigation supply to the system. Although D _U is relatively uniform (>?60%), E _a is relatively low (<?50%) indicating that the current irrigation management is inefficient. These findings have a paramount importance for improving irrigation water management in the Tunisian Saharan oases.  相似文献   

Landslide susceptibility mapping using AHP and fuzzy methods in the Gilan province,Iran     

Bahrami  Yousef  Hassani  Hossein  Maghsoudi  Abbas 《GeoJournal》2021,86(4):1797-1816

GeoJournal - Landslides are natural destructive phenomena that can cause great damage to property and life loss. One of the fundamental proceedings to reduce the possible damage is identifying...  相似文献   

A Unified Computational Method for Simulating Dynamic Behavior of Planing Vessels     

Mohammad Saeed SEIF  Ebrahim JAHANBAKHSH  Roozbeh PANAHI  Mohammad Hossein KARIMI 《中国海洋工程》2009,23(3):517-528

High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous f...  相似文献