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Indexing the engineering properties of residual soils in the southern slopes of Mashhad,NE Iran

Journal of Mountain Science 2020年第9期17卷 2179-2202页

作者： Saeedeh HOSSEINI Gholam Reza LASHKARIPOUR naser hafezi moghaddas Mohammad GHAFOORI Department of Geology Payame Noor UniversityPo Box 19395-3697TehranIran Department of Geology Faculty of ScienceFerdowsi University of MashhadMashhadIran

Residual soils are weathering products of rocks that are commonly found under unsaturated *** properties of residual soils are a function of the degree of weathering.A series of index properties,engineering properties and geophysics survey examinations were performed on residual soils from two major geological formations in *** the present research,the index properties of residual soils in the south of Mashhad city in Iran are *** and artificial trenches were analyzed for evaluating the weathering profiles and collecting soil *** and undisturbed samples were obtained from each of the soil profile horizons resulting from weathering of different parent ***,physical properties and mechanical properties of the soil samples were determined in accordance with ASTM ***,the mineralogical composition,chemistry,and texture of the soil were evaluated in 51 *** field observations showed the difference in the weathering profile of residual soils deposited on various rocks(igneous,sedimentary,and metamorphic).These profiles mainly consisted of two horizons includingresidual soil on top and saprolite at the *** results of laboratory tests and geotechnical data showed that the properties of residual soil samples change by ***,depending on the type of origin rock,the properties are different in various types of residual *** most of the samples,the moisture content of soil horizons was also increased by *** on the unified soil classification(USCS),the soils of the upper horizons appeared to be classified as ML(Lean silt)and CL(Lean clay)while the soils of the lower horizons(saprolite zone)fall in SC(clayey sand),SM(silty sand),and SW(wellgraded sand)***,the results demonstrated that the particle size of the soil was increased by *** of results of the geotechnical tests showed that properties of residual soils are changed by variations of depth,weat

关键词： Residual soil Rock weathering Geomechanical characteristics Mashhad City

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The Analysis of Transverse Topographic Symmetry Factor (T Index) in the Chekene-Mazavand, North East Iran

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Open Journal of Geology 2015年第11期5卷 809-820页

作者： Mohammad Reza Sajadian Mohsen Pourkermani Manochehr Qorashi naser hafezi moghaddas Department of Geology North Branch Islamic Azad University Tehran Iran Department of Geology Ferdowsi University Mashhad Iran

T index has been calculated in the Chekene-Mazavand region in the NE Iran. This index shows lateral tilting may be related to active tectonics. There are many streams and transverse topographic symmetry factor has been calculated for all streams of Kashafroud river. Firstly, based on digital elevation model, the study area was divided into 28 sub-basins. Then transverse topographic symmetry factor was calculated for each one. The values are between 0.14 and 0.57 and so, there are low, moderate and high levels of relative tectonic activities. The areas with low relative tectonic activities have found in sub-basins?no. 14, 15 and 24, moderate relative tectonic activities have found in sub-basinsno. 2, 5, 6, 7, 9, 10, 13, 16, 18, 19, 21, 22, 23, 25, 27 and 28 and high relative tectonic activities have found in sub-basins?no. 1, 3, 4, 8, 11, 12, 17, 20 and 26. The results show that the?plains have got low to moderate level of tectonic activity and faulted areas have got high tectonic activity. This matter is compatible with its tectonic setting on the Kopet Dagh belt in north east Iran.

关键词： Transverse Topographic Symmetry Factor Chekene-Mazavand Tectonic Iran

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Evaluating the Subgrade Reaction Modulus Variations with Soil Grains Shape in Coarse-Grained Soils Using Genetic Algorithm

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Open Journal of Geology 2020年第2期10卷 111-123页

作者： Pouya Salari naser hafezi moghaddas Gholam Reza Lashkaripour Mohammad Ghafoori Faculty of Science Ferdowsi University of Mashhad Mashhad Iran

Subgrade reaction modulus (Ks) is one of the main factors in evaluating engineering properties of soils for structural calculations and operations. So, many studies have been performed on the effect of other soil geotechnical parameters on it. One is the effect of soil grains shape on engineering properties of soils, especially Ks. The aim of the present research is to evaluate the effect of soil grains shape on Ks for coarse-grained soils of the west of Mashhad, Iran. For this purpose, 20 PLTs were performed on coarse-grained soils of the west of Mashhad and Ks amounts were determined. Then, flakiness and elongation of the samples measured and changes of Ks by soil grain shape were evaluated. The results showed the strength dependency of Ks to grain forms which an increase in flakiness and elongation indices leads to a decrease in Ks. Therefore, it is necessary to reduce Ks estimated form empirical relationships for flaky and elongated soils. So, by writing a genetic algorithm-based program to find the optimal relationship between the grain shape and the subgrade reaction coefficient, a valid equation for correcting the results from previous empirical equations was presented.

关键词： Subgrade Reaction Modulus (Ks) Flakiness Test Elongation Test Plate Load Test (PLT) Genetic Algorithm

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Identification of hidden faults using determining velocity structure profile by spatial autocorrelation method in the west of Mashhad plain(Northeast of Iran)

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Journal of Mountain Science 2021年第12期18卷 3261-3274页

作者： Seyedeh Fatemeh NEMATI naser hafezi MOGHADAS Gholam Reza LASHKARIPOUR Hosein SADEGHI Department of Geology Faculty of ScienceFerdowsi University of MashhadMashhad 91775-1436Iran

Characterizing the subsurface structure is an important parameter for the improvement of seismic hazard *** to the tectonic complexity of the earth,some deep fractures do not reach the earth's surface and are not detectable with visual ***,the lack of knowledge of faults and fractures can result in disasters,especially in urban *** geophysical methods can be used to estimate subsurface structure ***,a more reliable method is required to assess seismic hazards and reduce potential damage in metropolitan areas without destroying buildings and *** paper aims to identify hidden faults and structures using shear wave velocity *** do this,surface wave dispersion curve was extracted from the vertical component of microtremor array recording using the spatial autocorrelation(SPAC)method in two profiles and 13 array stations(perpendicular to the altitudes)to obtain shear wave velocity structure(Vs)in the west of Mashhad,northeast of *** results of shear wave velocity profiles(Vs)indicate sudden changes in the thickness of *** can be related to the displacement of a normal fault in this area causing the bottom rock to fall and an increase in the alluvial thickness in the central part of the *** velocity in the floor rock is 2000 meters per second in this *** to the surface outcrops and water wells data,its material is slate and Phyllite metamorphic rocks that are exposed in the adjacent ***,the seismic profile results were well consistent with electrical resistance data and well logs indicating that the tool array method is flexible,non-invasive,relatively fast,and effective for urban areas with satisfactory accuracy.

关键词： Subsurface Structure Hidden Fault Array Microtremor SPAC Method Vs Profile Mashhad Seismic hazard assessment

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Spatial Variability of Shear Wave Velocity Using Geostatistical Analysis in Mashhad City, NE Iran

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Open Journal of Geology 2014年第8期4卷 354-363页

作者： Azam Ghazi naser hafezi Moghadas Hossein Sadeghi Mohammad Ghafoori Gholam Reza Lashkaripour Department of Geology Faculty of Sciences Ferdowsi University of Mashhad Mashhad Iran

Shear wave velocity (Vs) is one of the most important parameters of a geological model to assess the site effect and the ground response. In this paper the spatial variability of shear wave velocity in Mashhad capital city are investigated. For this purpose, 243 Vs profiles of different projects throughout the city were used. Based on the Vs profiles the iso-level maps of the Vs interfaces 300, 500, 750, 950 and 1200 m/s were obtained by kriging interpolation method. The best semivariogram models were obtained with changing the effective parameters and assessing the components of the models and spatial dependence. The best models for the entire interfaces were exponential. Based on these models, the spatial dependence of depth data was moderate to strong. The performance of interpolations was checked by cross-validation and its indices?i.e. mean standardized prediction errors (MSPR), root mean square prediction errors (RMSPE), average kriging standard error (AKSE), and root mean square standardized prediction errors (RMSSPE) were assessed. A trend of depth increasing towards the northeast was observed at all of the interfaces.

关键词： Kriging Interpolation Accuracy Vs Interface Mashhad City

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