The behaviour of an artificially cemented sandy gravel   总被引：1，自引：0，他引：1  

S.?Mohsen?HaeriEmail author  S.?Mahdi?Hosseini  David?G.?Toll  S.?Shahaboddin?Yasrebi 《Geotechnical and Geological Engineering》2005,23(5):537-560

The major section of the city of Tehran, Iran has been developed on cemented coarse-grained alluvium. This deposit consists of gravely sand to sandy gravel with some cobbles and is dominantly cemented by carbonaceous materials. In order to understand the mechanical behaviour of this soil, a series of undrained triaxial compression tests and unconfined compression tests were performed on uncemented and artificially cemented samples. Portland cement type I was used as the cementation agent for preparing artificially cemented samples. Uncemented samples and lightly cemented samples (1.5% cement) tested at high confining pressure showed contractive behaviour accompanied with positive excess pore water pressure and a barrelling failure mode. However, cemented samples and uncemented samples tested at low confining pressure (25 and 50 kN/m²) showed dilative behaviour accompanied with negative excess pore water pressure. Shear zones were formed in these samples and a clear peak in excess pore water pressure and stress ratio against strain could be observed. Test results showed that the limiting stress ratio surface for cemented samples is curved and expands as the cementation and density increase. Unconfined compression strength of cemented samples increases with increases in cementation and density as well.  相似文献   

Extending a BIM-based data model to support 3D digital management of complex ownership spaces     

Behnam Atazadeh  Mohsen Kalantari  Abbas Rajabifard  Serene Ho  Tom Champion 《International journal of geographical information science》2017,31(3):499-522

Currently, 2D-based analogue building subdivision plans are used to represent the spatial extent of private, public and communal property ownership rights. These plans are recognized as posing a range of challenges in terms of communicating the spatial complexity of ownership spaces within multi-storey buildings. In response to these challenges, three-dimensional (3D) digital data environments are being investigated as a potential approach for managing complex, vertically stratified ownership arrangements. The argument presented in this article is that Building Information Modelling (BIM) can be adopted for 3D digital management of data related to complex ownership spaces. BIM provides a common and 3D digital data sharing space, underpinning a reliable basis for facilitating collaboration and decision-making over the lifecycle of buildings. However, ownership attributes and the spatial structure of ownership arrangements inside buildings are yet to be accommodated within the BIM data environment. In this article, we present a range of required data elements for managing complex ownership spaces, which have been elicited by investigating current practices pertaining to subdivision of ownership spaces within multi-storey buildings in Melbourne, Australia. An open data model in the BIM domain is extended with these data elements and a prototype model for a real multi-storey building is implemented to demonstrate the viability of the extended data model for 3D digital management and visualization of data related to complex ownership arrangements.  相似文献   

Study and numerical modeling of 1945 Makran tsunami due to a probable submarine landslide     

Ehsan Rastgoftar  Mohsen Soltanpour 《Natural Hazards》2016,83(2):929-945

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A BEM investigation on the influence of underground cavities on the seismic response of canyons     

Hamid Alielahi  Mohsen Kamalian  Mohammad Adampira 《Acta Geotechnica》2016,11(2):391-413

Two-dimensional site effects caused by cavities under topographical functions can considerably impact the seismic reaction of the ground surface. Due to the complexity of scattering issues by topographical features above subterranean cavity, few studies have been done in this field. In the present study, the seismic response of semi-sine-shaped canyons above a subterranean cavity (hole) of different dimensions, depths and locations is examined. The medium is assumed to have a linear elastic constitutive behavior exposed to vertically propagating incident SV and P waves. All calculations are performed using the direct boundary element technique in the time domain. It is observed that a cavity below a canyon can considerably change the ground response of the surface in different periodic bands. The seismic interaction between canyon and cavity with respect to various geometrical parameters will lead to different amplification patterns in the center and edge of the canyon. One of the most important results is the increase in amplification of long periods compared with the case of a canyon without cavity. Moreover, parametric research shows the fact that the cavity detail and canyon height, the ratio of cavity to the canyon size and cavity location impact on the seismic amplification of the canyon surface. Finally, spectral amplification coefficients of the canyon surface led by the cavity are reported for different cases of the canyon–cavity interaction.  相似文献   

Geochemistry of Triassic Carbonates: Exploration Guide to Pb–Zn Mineralization in North Tunisia          下载免费PDF全文

Nejib Jemmali  Fouad Souissi  Emmanuel John M. Carranza  Mohsen Henchiri 《Resource Geology》2016,66(4):335-350

The Triassic carbonate rocks in Northern Tunisia (Nappes, Domes, Jurassic Mountains zones), consist of massive carbonates, clays and gypsum with authigenic minerals. These are associated with several Pb–Zn deposits and occurrences. At Jebel Ichkeul, Bechateur and Oum Edeboua, these Triassic carbonates exhibit enrichment in Pb (0.32 to 228 ppm), Zn (17 to 261 ppm), Cd (5 to 6 ppm) and Co (0.3 to 89.5 ppm), with respect to their average contents in crustal carbonates. The enrichment is more pronounced at Oum Edeboua (near the ore zone). Permeability is one of the most effective factors of dispersion of metallic trace elements, causing the development of geochemical halos. The genetic relationship of the Triassic carbonate rocks with the ore deposits was controlled by diapirism and tectonic movements, which favored mineralization along the Triassic‐cover contact as well as the remobilization of metals from the mineralized rocks. Analysis of metallic trace elements in Triassic rocks provides clues to the presence of possible mineral deposits. These could be effectively used for both geochemical interpretation and mineral exploration. Carbon and O‐isotope data (– 9.3‰ < δ¹³C < +3‰; +21.9 < δ¹⁸O < +31‰) suggest that the Triassic carbonates of all study areas have marine carbonates as their origin; some of them show significantly lower δ¹⁸O values indicating some exchange with hydrothermal fluids. Calcites associated with mineralization at Oum Edeboua have δ¹³C of –6.2‰ to –8.22‰ and δ¹⁸O of +24.88‰ to +25‰. The C‐isotope compositions of these calcites are ¹³C depleted, indicating an organic origin.  相似文献   

Ontogenetic Changes in Vulnerability of the Prawn <Emphasis Type="Italic">Fenneropenaeus indicus</Emphasis> to UV-B Radiation Help Explain Ontogenetic Habitat Shifts     

Gopikrishna?Mantha  Ali?M.?Al-Aidaroos  Mohsen?M.?O.?El-Sherbiny  Sathianeson?Satheesh  Sambhu?Chithambaran  Carlos?M.?DuarteEmail author 《Estuaries and Coasts》2016,39(3):839-845

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Estimation of the Rock Load in Non-squeezing Ground Condition Using the Post Failure Properties of Rock Mass     

Mohsen Soleiman Dehkordi  H. A. Lazemi  K. Shahriar  Masoud Soleiman Dehkordi 《Geotechnical and Geological Engineering》2015,33(4):1115-1128

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Modeling Spatial Structure of Rock Fracture Surfaces Before and After Shear Test: A Method for Estimating Morphology of Damaged Zones     

Nima Babanouri  Saeed Karimi Nasab 《Rock Mechanics and Rock Engineering》2015,48(3):1051-1065

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Kinematic and dynamic analysis of North-Tehran tectonic wedge formed in south central Alborz, Iran     

Sareh Rajabi  Mohsen Eliassi 《Journal of the Geological Society of India》2012,80(5):731-737

To answer the question ??Whether the North-Tehran tectonic wedge is a dynamic tectonic wedge or not??? we applied paleostress techniques to investigate fault slip data. The mean reduced stress tensor is defined for all stabilized stress regions. Unscaled Mohr??s circles drawn for fault slip data were used to obtain the relative slip tendency of clusters on diagrams. It showed that the slip tendency in the vicinity of fault junction is much lower than expected. The mean??₁ defined for a combination of fault slip data trends N14°E nearly parallel with the overall pressure in Iranian crust at the latitude of Central Alborz. This trend suggests the least effect of boundary faults and the wedge between them on stress orientations inside the wedge. Finally, the stress trajectory map was prepared showing the configuration and relative intensity of ??₁. The map did not illustrate any convergence in ??₁ trajectories and the consequent concentration of stress and seismic potential in fault junction. That is a direct evidence for disagreeing the dynamicity of this tectonic wedge.  相似文献   

Statistic and genetic investigation of faults in North Tehran tectonic wedge (South Central Alborz)     

Sareh Rajabi  Mohsen Eliassi  Abdollah Saidi 《Arabian Journal of Geosciences》2012,5(6):1269-1277

In this research, we have focused on the geometrical characteristics of young faults in North Tehran tectonic wedge which is confined with the Mosha and North Tehran faults, the most outstanding active faults in Alborz fold-thrust belt. The statistical, genetic, and kinematic relationships between internal faults, boundary faults, and the stress regime in the area (at the finite state of deformation path) are considered in detail with the help of rose diagrams and Riedel??s model. On this basis, all faults with diverse mechanisms have been classified into different Riedel fractures and their orders of formation are identified. Pattern of faults implies a more or less N?CS compression at the period of faulting. Consideration of geometry and tectonic setting of abundant normal faults have led to propose folding and listric faulting model to explain the origin of normal faults in a compressional tectonic region. These structural models represent the mechanism of normal faulting in response to compression in crustal and upper crustal scales, respectively.  相似文献