, Saga, Japan
, Tarbiat Modares University,
, Shiraz university,
Mashalah Khamehchiyan, born in 1959 in Kashan, Iran, received B.Sc. degree in Geology from Shiraz university in Shiraz in 1989 and M.Sc. degree in Engineering Geology from Tarbiat Modares University in Tehran in 1990. He received his Ph.D. degree in Engineering Geology from Saga University, Saga-Japan in 1994. His thesis was on the Study of geotechnical and geoenvironmental aspects of land subsidence due to withdrawal of ground water. Prof. Khamehchiayn?s research interests include Land subsidence due to groundwater lowering, geoenvironmental engineering, engineering properties of soils and rocks. Since 1994, he has been an academic member in the department of engineering geology at Tarbiat Modares University in Tehran, Iran, teaching graduate courses in engineering geology (rock mechanics, soil mechanics, ground water and geotechnical problems, advanced rock mechanics, environmental geotechnics) as well as supervisingadvising M.Sc.Ph.D. theses. Together with his students and research associates, prof. Khamehchiayn has made important contributions to understanding the Land Subsidence due to Groundwater Lowering in Iran. The results of his research have appeared in almost 70 refereed journal articles and 150 conference articles. Prof. Khamehchiayn has been among the founding board of the Iranian Association of Engineering Geology (IAEG) and a member of the Board of Directors and dean of IAEG. He has been the chief editor of Engineering Geology journal of IAEG. He is among editorial board of Engineering Geology journal of IAEG, GeoPersia and Engineering Geology journal of Kharazmi university.
Microcracks are an integral part of intact rocks that can develop when the rock is exposed to static or dynamic loads. The loading may not fail the rock. It, however, may cause permanent damage to the sample by expanding the existing microcracks or developing new microcracks. Investigating the development of microcracks in intact rocks is significant to investigate the damage evolution, which is not visible in macro-scale. In this study, the evolution of microcracks in gabbro is investigated under static and dynamic loading. Gabbro samples were subjected to monotonic and cyclic loading until a crack stress threshold (ie, crack closure, crack initiation, crack damage). After each test, microcracking properties of the sample such as Linear Mi
Despite the high performance of dynamic penetration tests such as dynamic cone penetrometer (DCP) for assessing the engineering properties of site materials, they are not efficient for vertical soil walls. To deal with this issue, an automatic portable time-saving horizontal dynamic cone penetrometer (HDCP) was invented in this study. A set of HDCP model tests were performed on the Tehran young alluvial sediments at different depths and various relative densities, which indicated the high repeatability of the developed equipment with the coefficient of variation (COV) ranging from 7 to 16 %. Multiple correlations were developed between the HDCP output, i.e., dynamic penetration index (DPI), and the parameters including relative density, You
Salt crystallization-induced decay of Vardavard granodiorite and Shirkouh monzogranite, two Iranian building stones, were assessed with two non-destructive methods: saturation-buoyancy technique and P-and S-wave velocity measurement. Moreover, polarized and fluorescence microscopy studies were used to evaluate the behavior of the studied stones at microscopic scale against a salt crystallization aging test. The aging test extended pre-existing microcracks and generated new ones. Intracrystalline microcracking was the most predominant microcrack type for both samples. Fine-grained Vardavard granodiorite experienced higher intercrystalline microcracking than coarse-grained Shirkouh monzogranite. The microcracking mechanism of feldspars substa
Considering the diverse climatic conditions of Iran with a varying from hot and dry and also coastal areas it can be seen that salt weathering is one of the most important agents affecting on the durability of stones used as wall cladding of the building.? As a result it is necessary that durability of stones be assessed and the most resistance and appropriate those be selected for use as wall cladding of the buildings. In this research, durability of six samples of travertines from Azarshahr and Mahallat areas against salt weathering were investigated. For this purpose, salt weathering test at sulfate sodium (Na2SO4) up to 60 cycles was carried out and, after every 5 cycles, changes in the samples appearance (color, efflorescence, chemical
Charosa and Dehdasht is a part of folded Zagros that is located in the Kohgiluyeh and Boyer-Ahmad Province in southwestern Iran. This area is covered with several Zagros anticlines such as the Kuh-e-Sefid, Sartal, Nil, and Siah. From the geological perspective, the Ilam–Sarvak formation makes the major and high altitudes of the region. Numerous landslides have occurred in the highlands of this area, with the largest known landslides being the Mundan rock avalanche in the Nil anticline with an approximate volume of more than one billion cubic meters and the Almor rock avalanche in the Sartal anticline. This study explores the probable triggering factors of these landslides based on geological studies, seismotectonic studies, and numerical
Salt crystallization-induced decay of Vardavard granodiorite and Shirkouh monzogranite, two Iranian building stones, were assessed with two non-destructive methods: saturation-buoyancy technique and P- and S-wave velocity measurement. Moreover, polarized and fluorescence microscopy studies were used to evaluate the behavior of the studied stones at microscopic scale against a salt crystallization aging test. The aging test extended pre-existing microcracks and generated new ones. Intracrystalline microcracking was the most predominant microcrack type for both samples. Fine-grained Vardavard granodiorite experienced higher intercrystalline microcracking than coarse-grained Shirkouh monzogranite. The microcracking mechanism of feldspars subst
This study is an attempt to investigate the effect of the nano-kaolinite concentration on the liquefaction resistance of liquefiable sand from Gorgan city of Iran. To examine the influence of the nano-kaolinite concentration on the liquefaction resistance of nano-kaolinite-sand mixtures, three different nano-kaolinite concentrations: 3%, 6% and 9% were prepared. Cyclic triaxial tests were conducted on pure sand and nano-kaolinite-sand mixtures. Triaxial test was repeated two times for each nano-kaolinite-sandy soil mixtures and the mean values and standard deviation was obtained. Based on the obtained results, nano-kaolinite concentration has a contradictory effect on the liquefaction resistance of the studied soil. It was found that the in
The increase of heavy metals concentration in soils is potentially threatening the environment and human health. In this paper, multivariate analysis methods such as Positive Matrix Factorization (PMF), Principal Component Analysis (PCA) and Cluster Analysis (CA) combined with geostatistical method were employed to identify the potential sources of soil pollution. A collection of 103 samples were obtained from surface soils of different types of lithology and landuse in Zanjan Basin, Iran. The concentration of As, Bi, Cd, Co, Cr, Cu, Pb, Fe, Mo, Ni, Zn, Se and Hg beside of physical and chemical properties were measured. The results showed a strong effect of anthropogenic sources on the enrichment of heavy metals especially, Zn, Pb, Cd, As a
Crack evolution in a rock depends on the mineralogy, microstructure and fabric of specific rock type. This study aims to investigate how mineralogy and grain shape affect the microcrack initiation and propagation of granite rock, which contains plagioclase, quartz, k-feldspar, biotite and amphibole, during uniaxial compression loading. Physico-mechanical properties and microcrack features such as linear microcrack density (LMD) and microcrack type were investigated. By acoustic emission (AE) measurements, damage stress thresholds were identified. Then, crack characteristics of a fresh sample were compared with the samples that were loaded until damage threshold stresses. The results demonstrate that at an early stage of loading, pre-existin
The aim of this study is to analyze the interactions among the different factors influencing the performance of the reverse logistics chain. We attempted to explore the factors touching performance of reverse logistics relatively to customer satisfaction. We have proposed a structural analysis based on MICMAC (Impact Matrix Cross-Reference Multiplication Applied to a Classification) method to classify factors rendering their direct/indirect influences and dependencies. The upshot of this research is to identify the relationship between the 31 variables used in the experimentation. It observed that this exploration might cooperate in reverse logistics policy development arrangement, motivated by customer necessity.
Land subsidence due to groundwater resources extraction is one of the abundance events occurred in Iran. If it is not properly managed, this phenomenon can cause irreparable damage to the affected areas. Population growth and agricultural technology have also led to overexploitation of the groundwater resources in some parts of Iran. The rate of land subsidence due to overexploitation of the groundwater in Tehran plain has increased over recent years. Under such conditions, its harmful effects on agricultural land, buildings, infrastructures, and surface deformations, in the form of sinkhole, cracks and fissure are expanding. In this research by using the ALPRIFT model, which is a simple weighing model, consisting of seven layers of subside
Durability is the most important characteristic of stones in sustainable architecture. Salt crystallization has been known to damage porous building stones. Gerdoi and red travertines are extensively used in new buildings in East Azerbaijan province. To this end, petrographic and physical properties, dry and saturated P-wave velocity, uniaxial compressive strength and Brazilian tensile strength were obtained for each freshly quarried stone in the laboratory. The samples were subjected to an aging test in order to examine their resistance against sodium chloride crystallization. Water saturated-to-dry strength ratio (a crude immediate estimator) and a decay function model were applied to assess durability of stones. Gerdoi trave
Durability of building stones is an important issue in sustainable development. Crystallization of soluble salts is recognized as one of the most destructive weathering agents of building stones. For this reason, durability of Ghaleh-khargushi rhyodacite and Gorid andesite from Iran was investigated against sodium sulfate crystallization aging test. Petrographic and physico-mechanical properties and pore size distribution of these stones were examined before and after the aging test. The characteristics of the microcracks were quantified with fluorescence-impregnated thin sections. Durability and physico-mechanical characteristics of Ghaleh-khargushi rhyodacite are mainly influenced by preferentially oriented preexisting micr
The porosity of travertine controls its strength characters and durability. In this study, seven travertine samples were collected from mines in Iran. The saturation-buoyancy (SB) method was used to determine density, water absorption by weight, effective porosity, and total porosity. Petrographic image analysis (PIA) was applied to measure total porosity. Uniaxial compressive strength (UCS) of travertine samples was obtained under both oven-dried and saturated conditions. The results showed that mean PIA total porosity of samples is 2–4 times more than total porosity obtained from the SB method. The underestimation of total porosity by SB method was attributed to pores type and pores size. According to regression analyses,
Since the population increasing and the development of agricultural activities in the south-western plain of Tehran have led to increasing underground water drainage, the assessment of the vulnerability of the areas exposing to subsidence has become more important. In this research, the vulnerability of the south-western plain of Tehran to subsidence has been investigated using ALPRIFT method in ArcGIS and optimization of the ALPRIFT method has been performed using SVM. In order to implement the ALPRIFT method, effective parameters including aquifer media, land use, groundwater pumping, recharge, aquifer thickness, faults distance and groundwater decline were used to assess the subsidence susceptibility. These are ranked in seven separate l
Salt crystallization is one of the most powerful weathering agents that may cause a rapid change in the mechanical properties of stones, and thus limit their durability. Consequently, determining the mechanical properties of stones due to salt crystallization is important for natural building stones used in marine environmental and mild climatic conditions, which expose excessive salt crystallization cycles. In this study, multivariate regression analysis was performed for estimating the mechanical properties of travertine building stones after salt crystallization test. For this purpose, 12 travertine samples were selected and their physical and mechanical properties (density, porosity, uniaxial compressive strength, Brazilian tensile stre
Determination of the mechanical strength of stones after freeze–thaw action is important for evaluating the durability of natural building stones used in cold regions. In this research, we proposed a novel physico-mechanical parameter (PMP) for estimating the mechanical strength of travertines after a freeze–thaw test, which is based on initial mechanical strength, effective porosity, and mean pore size of the stones. For this purpose, 12 samples of travertines were selected and their initial mechanical strengths (uniaxial compressive, Brazilian tensile and point load strengths), effective porosity, and mean pore size were determined. Then a freeze–thaw test was conducted up to 60 cycles on samples, and their mechanical
Experimental tests were conducted on a drainage channel with an energy dissipation structure and four channel slopes. Differences in the drainage channel were observed when the debris flow passed the energy dissipation structure. Additionally, the time-averaged debris-flow depth at the energy dissipation structure section was 1.78 times deeper than those in the upstream and downstream locations of...
no record found