Earthquake-resistant design according to the most unfavourable seismic direction under combined internal forces     

Adnan lakirolu 《地震工程与结构动力学》1987,15(7):853-864

In this study it has been shown that, in the case of linear theory, the combined internal forces corresponding to each seismic direction lie on an ellipsoid having internal forces chosen as the set of axes. A method is proposed to obtain the most unfavourable results easily, in the neighbourhood of the several unfavourable points without actually determining the ellipsoid. The design can be carried out using linear, as well as non-linear, theory. Two examples are given to illustrate the application of the proposed method.  相似文献   

Thermal shock weakening of granite rock under dynamic loading: 3D numerical modeling based on embedded discontinuity finite elements     

Timo Saksala  Adnan Ibrahimbegovic 《国际地质力学数值与分析法杂志》2020,44(13):1788-1811

This paper presents a numerical study of thermal shock weakening of granite rock under dynamic loading. A fully 3D numerical scheme based on a combined continuum viscodamage-embedded discontinuity model and an explicit scheme to solve the underlying thermomechanical problem was developed and validated through numerical examples. First, the dynamic Brazilian disc test is simulated on intact numerical rock. Then, thermal shock-induced cracking due to a moving external heat flux boundary condition, mimicking experiments based on plasma jet treatment, is numerically predicted. Finally, numerical Brazilian disc test is conducted on the thermal shocked numerical samples. The predicted and experimental weakening effects are in good agreement demonstrating that the present modeling approach has good predictive capabilities. The practical significance of the results is that heat shock pretreatment can substantially enhance rock gravel and rubble crushing.  相似文献   

Analyzing the occurrence of floods and droughts in connection with climate change in Punjab province,Pakistan     

Ali  Syeda Maria  Khalid  Bushra  Akhter  Asma  Islam  Aneeza  Adnan  Shahzada 《Natural Hazards》2020,103(2):2533-2559

Natural Hazards - Frequency and intensity of extreme weather events are immensely changing throughout the world. This study aims to give insight into the changing climatic patterns leading to...  相似文献   

Hydrologic response to future land use change in the Upper Mississippi River Basin by the end of 21st century   总被引：1，自引：0，他引：1       下载免费PDF全文

Adnan Rajib  Venkatesh Merwade 《水文研究》2017,31(21):3645-3661

This study demonstrates the spatial variation in hydrologic processes across the Upper Mississippi River Basin (UMRB) by the end of 21st century, by ingesting FOREcasting Scenarios (FORE‐SCE) of Land‐use Change projections into a physics‐based hydrologic model—Soil and Water Assessment Tool. The model is created for UMRB (440,000 km²), using the National Landcover Database of year 2001 and climate data of 1991–2010. Considering 1991–2010 as the baseline reference period, FORE‐SCE projections of year 2091 under three scenarios (A1B, A2, and B1 from the Intergovernmental Panel on Climate Change) are separately assimilated into the calibrated model, whereas climate input is kept the same as in the baseline. Modeling results suggest an increase of 0.5% and 3.5% in the average annual streamflow at the basin outlet (Grafton, Illinois) during 2081–2100, respectively, for A1B and A2, whereas for B1, streamflow would decrease by 1.5%. Under the “worst case” A2 scenario, 6% and 133% increase, respectively, in agricultural and urban areas with 30% depletion of forest and grassland would result into 70% increase in surface runoff, 20% decrease in soil moisture, and 4% decrease in evapotranspiration in certain parts of the basin. Conversion of cropland, forest, or grassland to perennial hay/pasture areas would lower surface runoff by 25% especially in the central region, whereas persistent forest cover in the northern region would cause up to 7% increase in evapotranspiration. The ecosystem in the lower half of UMRB is likely to become adverse, as dictated by a composite water–energy balance indicator. Future land use change extents and resultant hydrologic responses are found significantly different under A2, A1B, and B1 scenarios, which resonates the need for multi‐scenario ensemble assessments towards characterizing a probable future. The spatial variation of hydrologic processes as shown here helps to identify potential “hot spots,” giving ways to adopt more effective policy alternatives at regional level.  相似文献   

Seismic bearing capacity of strip footing on partially saturated soil using modal response analysis     

Abhijit Anand  Rajib Sarkar 《地震工程与工程振动(英文版)》2022,21(3):641-662

The present study proposes a novel and simplified methodology to assess the seismic bearing capacity(SBC) of a shallow strip footing by incorporating strength non-linearity arising due to partial saturation of a soil matrix. Furthermore, developed methodology incorporates the modal response analysis of soil layers to assess SBC. A constant matric suction distribution profile has been considered throughout the depth of the soil. The Van Genuchten equation and corresponding fitting parameters have...  相似文献   

The Importance of Chert in Central Anatolia: Lessons from the Neolithic Assemblage at Çatalhöyük,Turkey     

Adam Joseph Nazaroff  Adnan Baysal  Yahya ifti 《Geoarchaeology》2013,28(4):340-362

This paper is a presentation of three sources of artifact‐quality chert in Central Anatolia. A previous dearth of research focused on locating and characterizing such raw material sources has incorrectly colored our view of prehistoric economic practices. To remedy this situation, we have conducted a survey of various locales within Central Anatolia to test for the presence of artifact‐quality materials. We make use of Individual Attribute Analysis (IAA) and Energy Dispersive X‐ray Fluorescence (EDXRF) analysis to discriminate among these materials, and suggest their use by the Neolithic occupants of Çatalhöyük through similar analyses of artifactual materials. We argue that the presence and characterization of these new sources allows us to better understand the intricacies of Neolithic practices by illustrating the ways in which the consumption of these materials was variably entwined with the exploitation of other resources, as well as embedded within social relations outside of Central Anatolia. © 2013 Wiley Periodicals, Inc.  相似文献   

Comparison of two snowmelt modelling approaches in the Dudh Koshi basin (eastern Himalayas,Nepal)     

Bijay Kumar Pokhrel  Pierre Chevallier  Vazken Andréassian  Adnan Ahmad Tahir  Yves Arnaud  Luc Neppel 《水文科学杂志》2013,58(8):1507-1518

Abstract

The glaciers in the Nepalese Himalayas are retreating due to rising temperatures. Lack of data and information on Nepal’s cryosphere has impeded scientific studies and field investigations in the Nepalese Himalayas. Therefore, IRD France and Ev-K2 CNR Italy have conducted the PAPRIKA (CryosPheric responses to Anthropogenic PRessures in the HIndu Kush-Himalaya regions: impacts on water resources and society adaptation in Nepal) project in Nepal with the financial support of the French and Italian scientific agencies. This project aims to address the current and future evolution of the cryosphere in response to overall environmental changes in South Asia, and its consequences for water resources in Nepal. Thus, two hydrological models, the GR4J lumped precipitation–runoff model and the snowmelt runoff model (SRM), were used in the Dudh Koshi basin. The GR4J model has been successfully applied in different parts of Europe. To obtain better results in such a harsh and rugged topography, modifications needed to be made, particularly in the snow module. The runoff pattern is analysed herein both for past years and, in a sensitivity analysis, for possible future climatic conditions (i.e. precipitation and temperature) using the SRM and GR4J modelling approaches. The results reveal a significant contribution of snow- and glacier-melt to runoff, and the SRM model shows better performance in Nepalese catchments than the GR4J model.