Investigation of Failed Slopes Based on a New Method of Back Analysis in Rock Masses: A Case Study     

Taherynia  Mohammad Hossein  Koopialipoor  Mohammadreza  Azizzadeh  Abbas  Fahimifar  Ahmad  Ghyasvand  Soheil 《Geotechnical and Geological Engineering》2021,39(7):5119-5133

Geotechnical and Geological Engineering - Small variation in shear strength parameters results in remarkable changes in the safety factor (SF) of a rock slope. In this regard, rock mass strength of...  相似文献   

APG:A novel python-based ArcGIS toolbox to generate absence-datasets for geospatial studies     

Seyed Amir Naghibi  Hossein Hashemi  Biswajeet Pradhan 《地学前缘(英文版)》2021,12(6):90-104

One important step in binary modeling of environmental problems is the generation of absence-datasets that are traditionally generated by random sampling and can undermine the quality of outputs.To solve this problem,this study develops the Absence Point Generation(APG)toolbox which is a Python-based ArcGIS toolbox for automated construction of absence-datasets for geospatial studies.The APG employs a frequency ratio analysis of four commonly used and important driving factors such as altitude,slope degree,topographic wetness index,and distance from rivers,and considers the presence locations buffer and density layers to define the low potential or susceptibility zones where absence-datasets are gener-ated.To test the APG toolbox,we applied two benchmark algorithms of random forest(RF)and boosted regression trees(BRT)in a case study to investigate groundwater potential using three absence datasets i.e.,the APG,random,and selection of absence samples(SAS)toolbox.The BRT-APG and RF-APG had the area under receiver operating curve(AUC)values of 0.947 and 0.942,while BRT and RF had weaker per-formances with the SAS and Random datasets.This effect resulted in AUC improvements for BRT and RF by 7.2,and 9.7％from the Random dataset,and AUC improvements for BRT and RF by 6.1,and 5.4％from the SAS dataset,respectively.The APG also impacted the importance of the input factors and the pattern of the groundwater potential maps,which proves the importance of absence points in environmental bin-ary issues.The proposed APG toolbox could be easily applied in other environmental hazards such as landslides,floods,and gully erosion,and land subsidence.  相似文献   

Pore-water pressure development in a frozen saline clay under isotropic loading and undrained shearing     

Lyu  Chuangxin  Nishimura  Satoshi  Amiri  Seyed Ali Ghoreishian  Zhu  Feng  Eiksund  Gudmund Reidar  Grimstad  Gustav 《Acta Geotechnica》2021,16(12):3831-3847

Acta Geotechnica - A systematical testing program on frozen Onsøy clay under isotropic loading and undrained shearing at different temperatures...  相似文献   

Formulation of the Caspian Sea’s legal regime using a joint zone approach     

Seyed Amin Nejat  Davoud H. Bavand  Parvin Farshchi 《Water Resources》2016,43(3):571-578

The legal regime of the Caspian Sea has been determined under Treaties 1921 and 1940 by and between Iran and former Soviet Union. In fact, we are neither to explain it nor to determine. As understood from the provisions therein, the exploitation and use of the Caspian Sea by both countries are based on the Condominium. However, there is a 10-nautical mile strip as exclusive fishing areas which have been allocated to the states under the 1940 treaty. It means that Soviet Union and Iran may benefit the marine livings resources out of that strip on an equal manner. This right also includes the seabed and underlying bed. So, the legal regime of this sea may be based on a 10-nautical mile exclusive region for all five states and the remaining part as common and joint area under an agreement until an explaining and supervising organization is established to exploit and supervise over living and non-livings resources.  相似文献   

Spatial modelling of reference evapotranspiration using adjusted Blaney-Criddle equation in an arid environment     

Hossein Tabari  B. Shifteh Some'e 《水文科学杂志》2013,58(2):408-420

Abstract

The Blaney-Criddle (BC) temperature-based equation is used in areas where the complete weather data to estimate reference evapotranspiration (ET₀) by the Penman-Monteith FAO-56 (PMF-56) standard model is complex. In this study, the BC equation was first tested and calibrated against the ET₀ values computed by the PMF-56 method using data from 17 weather stations in arid regions of Iran. Then, geographical information systems (GIS)-based spatially-distributed maps of ET₀ were prepared by means of geographic/topographic factors derived from a digital elevation model (DEM) for all months, separately. The results indicate that the original BC equation overestimated PMF-56 ET₀ by 4% at the study sites. The BC equation produced closer ET₀ estimates to the PMF-56 method after it was calibrated. The error rate of <3% for the spatial modelling approach suggests that the developed ET₀ maps are reliable.

Editor D. Koutsoyiannis; Associate editor D. Yang

Citation Tabari, H., Hosseinzadeh Talaee, P., and Shifteh Some'e, B., 2013. Spatial modelling of reference evapotranspiration using adjusted Blaney-Criddle equation in an arid environment. Hydrological Sciences Journal, 58 (2), 408–420.  相似文献   

Neuro-fuzzy models employing wavelet analysis for suspended sediment concentration prediction in rivers     

Seyed Ahmad Mirbagheri  Taher Rajaee  Amir Alikhani 《水文科学杂志》2013,58(7):1175-1189

Abstract

The study of sediment load is important for its implications to the environment and water resources engineering. Four models were considered in the study of suspended sediment concentration prediction: artificial neural networks (ANNs), neuro-fuzzy model (NF), conjunction of wavelet analysis and neuro-fuzzy (WNF) model, and the conventional sediment rating curve (SRC) method. Using data from a US Geological Survey gauging station, the suspended sediment concentration predicted by the WNF model was in satisfactory agreement with the measured data. Also the proposed WNF model generated reasonable predictions for the extreme values. The cumulative suspended sediment load estimated by this model was much higher than that predicted by the other models, and is close to the observed data. However, in the current modelling, the ANN, NF and SRC models underestimated sediment load. The WNF model was successful in reproducing the hysteresis phenomenon, but the SRC method was not able to model this behaviour. In general, the results showed that the NF model performed better than the ANN and SRC models.

Citation Mirbagheri, S. A., Nourani, V., Rajaee, T. & Alikhani, A. (2010) Neuro-fuzzy models employing wavelet analysis for suspended sediment concentration prediction in rivers. Hydrol. Sci. J. 55(7), 1175–1189.  相似文献   

Scattering of plane harmonic SH,SV, P and rayleigh waves by non-axisymmetric three-dimensional canyons: A wave function expansion approach     

Hossein Eshraghi  Marijan Dravinski 《地震工程与结构动力学》1989,18(7):983-998

Scattering of elastic waves by three-dimensional canyons embedded within an elastic half-space is investigated by using a wave function expansion technique. The geometry of the canyon is assumed to be non-axisymmetric. The canyon is subjected to incident plane Rayleigh waves and oblique incident SH, SV and P waves. The unknown scattered wavefield is expressed in terms of spherical wave functions which satisfy the equations of motion and radiation conditions at infinity, but they do not satisfy stress-free boundary conditions at the half-space surface. The boundary conditions are imposed locally in the least-squares sense at several points on the surface of the canyon and the half-space. Through a comparative study the validity and limitations of two-dimensional approximations (antiplane strain and plane strain models) have been examined. It is shown that scattering of waves by three-dimensional canyons may cause substantial change in the surface displacement patterns in comparison to the two-dimensional models. These results emphasize the need for three-dimensional modelling of realistic problems of interest in strong ground motion seismology and earthquake engineering.  相似文献   

Regional geopotential model improvement for the Iranian geoid determination   总被引：1，自引：0，他引：1  

Georg Weber  Hossein Zomorrodian 《Journal of Geodesy》1988,62(2):125-141

Spherical harmonic expansions of the geopotential are frequently used for modelling the earth’s gravity field. Degree and order of recently available models go up to 360, corresponding to a resolution of about50 km. Thus, the high degree potential coefficients can be verified nowadays even by locally distributed sets of terrestrial gravity anomalies. These verifications are important when combining the short wavelength model impact, e.g. for regional geoid determinations by means of collocation solutions. A method based on integral formulae is presented, enabling the improvement of geopotential models with respect to non-global distributed gravity anomalies. To illustrate the foregoing, geoid computations are carried out for the area of Iran, introducing theGPM2 geopotential model in combination with available regional gravity data. The accuracy of the geoid determination is estimated from a comparison with Doppler and levelling data to ±1.4m.  相似文献   

L'Association Shoshonitique du Damavand (Iran)     

Robert Brousse  Hossein Moine Vaziri 《International Journal of Earth Sciences》1982,71(2):687-702

Résumé La suite magmatique du Damavand — un volcan isolé dans l'Elbroz, au Nord de l'Iran-a les caractéristiques d'une association magmatique avec absarokite-shoshonitebanakite. Toutefois, la relative rareté des termes intermédiaires permet de poser le problème de l'unicité de la série.L'origine de ces laves potassiques est discutée en fonction d'une paléosubduction océanique, partie du Zagros à l'Aquitanien ou, alternativement, en fonction d'une structure naissante de la Caspienne.

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Zusammenfassung Die magmatische Serie von Damavand, aus einem isolierten Vulkan in der nordiranischen Elbroz-Provinz, weist alle Eigenschaften einier Absarokit-Shoshonit-magmatischen Assoziation auf.Die Herkunft dieser Kalilaven wird in bezug auf einer ozeanischen Palaeosubduktion, die im Zagros während des Aquitains anfing, diskutiert. Die Alternative eines Zusammenhangs mit der kaspischen Struktur wird in Betracht gezogen.The Damavand magmatic series — from an isolated volcano in the Elbroz province, north of Iran — holds all characters of an absarokite-shoshonite-banakite magmatic association. However, the intermediate terms are too seldom to solve the problem of the series unity.The origin of these potassic lavas is discussed as related to either an oceanic paleosubduction which started from the Zagros at Aquitanian, or, possibly, related to the evolving Caspian structure.

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Upper-mantle structure of the Baltic Shield below the Swedish National Seismological Network (SNSN) resolved by teleseismic tomography     

Tuna Eken  Z. Hossein Shomali  Roland Roberts  Reynir Bödvarsson 《Geophysical Journal International》2007,169(2):617-630

Upper-mantle structure under the Baltic Shield is studied using non-linear high resolution teleseismic P -phase tomography. Observed relative arrival-time residuals from 52 teleseismic earthquakes recorded by the Swedish National Seismological Network (SNSN) are inverted to delineate the structure of the upper mantle. The network consists of 47 (currently working) three-component broad-band stations located in an area about 450 km wide and 1450 km long. In order to reduce complications due to possible significant three-dimensionality of Earth structure, events chosen for this study lay close to in-line with the long-axis of the array  (±30°)  . Results indicate P -wave velocity perturbations of ±3 per cent down to at least 470 km below the network. The size of the array allows inversion for structures even at greater depths, and lateral variations of velocity at depths of up to 680 km appear to be resolved. Below the central part of the array (60°–64° N), where ray coverage is best, the data reveals a large region of relatively low velocity at depths of over about 300 km. At depths less than about 250–300 km, the models include a number of features, including an apparent slab-like structure dipping gently towards the north.  相似文献