Mohammad Ghafoori

• PhD
• Professor (Full) at Ferdowsi University of Mashhad

This study investigates the influence of microstructural homogeneity—characterized by crack-related parameters such as crack porosity, crack density, and crack aspect ratio—on the accuracy of models predicting saturated wave velocities, including those based on Gassmann, Biot, and Mavko-Jizba theories, as well as their effects on wave dispersion. W...

In excavation tunnels with properties of inflatable sedimentary rocks, the change in floor height and movement of side walls inwards is often observed and causes tension and destruction of the structure. Stones that swell also exhibit viscoelastic behavior, possibly due to the sliding of clay layers. In order to determine the physical and mechanica...

The design of underground or terrestrial structures on the rock bed depends on the physical and mechanical properties. Considering the mining method in Tabas coal mine extraction method is long and destructive, the evaluation of the geomechanical properties of the rocks is more necessary. In this research, the characteristics of the rock units of t...

This paper deals with engineering geological properties of Qadis Khordak dam site in Northwest Afghanistan. This study is based on on-site and laboratory tests, surface discontinuity surveying, drilled borehole and permeability test of dam foundation. The engineering geological properties at the dam site were studied in order to evaluate geotechnic...

Determination of strength properties of intact rock using artificial cores has been considered in recent years. In this study, some relationships for estimating the static properties of dolomudstone cores of the Asmari reservoir were presented using artificial cores prepared from cuttings of two wells, southwest of Iran. For this purpose, first nat...

Determination of strength properties of intact rock using artificial cores has been considered in recent years. In this study, some relationships for estimating the static properties of dolomudstone cores of the Asmari reservoir were presented using artificial cores prepared from cuttings of two wells, southwest of Iran. For this purpose, first nat...

Karstification is a phenomenon that is more common in limestone and gypsum than in other rocks. Despite their equal geological conditions such as tectonics and hydrology, karstification in limestone and gypsum is different in the Ramhormoz area in Zagros folded zone in the southwest of Iran. This study aims to evaluate the lithological, physical, a...

Estimating the static properties of rocks, especially low-strength rocks, is time-consuming, costly, and in some cases impossible. The current study was carried out to evaluate the petrographic (XRD, thin section, and calcimetry), physical (porosity, absorption, density), mechanical [uniaxial compressive strength (UCS), Young’s modulus (Es), Poisso...

Static parameters are one of the most important parameters in estimating geomechanical properties. Determining these data is very costly in field studies, so they are not normally available and are limited in scope. Hence, many researchers have tried to provide empirical relationships to estimate these parameters from other characteristics. The aim...

One of the main problems related to mature oilfields is the decreased pore pressure due to hydrocarbon production. Therefore, to maintain the production rate of a reservoir, the lost pressure must be compensated. A very traditional method to increase the pressure is to inject natural gas into the reservoir. This technique is widely used in SW Irani...

Casing collapse is a costly phenomenon in drilling industry that occurred in different geological environment with different geomechanical property. Geomechanical and numerical analysis of casing collapse in Sirri-E, one of the offshore Iranian oilfield in Persian Gulf has been investigated in this work. In this study we tried to model several coll...

Subgrade reaction modulus (Ks) is one of the most important soil parameters to perform structural calculations and analysis. Ks directly affects the determination of dimensions and reinforcement of foundations. Therefore, its exact and accurate determination is of significant importance in terms of economy and safety, especially in large structures...

Residual soils are weathering products of rocks that are commonly found under unsaturated conditions. The 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 Iran. In t...

Evaluating the Subgrade Reaction Modulus Variations with Soil Grains Shape

Climate and geological conditions are among main the factors that can affect the erosion and natural dissolution of rocks. In the present study, we investigate the solubility variation of 144 rock samples taken from different depths of Tirgan limestone formation (Kopet-Dagh Mountains) under various pH (CO2 injection) and temperature conditions duri...

The attempts made to understand and quantify the relationship between rock texture and engineering properties have been accompanied by some ambiguities and uncertainties, and the majority of the approaches, though focusing on particular rock types, have not been so successful for even the same rock types from other regions. This study, therefore, w...

The article was originally published with incorrect capturing of author name. The name of the first author A. Rastegar Nia was incorrect. His name has now been corrected as A. Rastegarnia. The correct name is presented here.

Knowing the current condition of the faults and fractures in a reservoir is crucial for production and injection activities. A good estimation of the fault reactivation potential in the current stress field is a useful tool for locating the appropriate spot to drill injection wells and to calculate the maximum sustainable pore pressure in enhanced...

Wastewater contamination of fine-grain soils in urban aquifers leads to considerable changes in chemical, physical, and strength properties of this type of soil. This phenomenon is important because the contamination of foundation soils in an urban area by rising of the water table due to infiltration of wastewater may result in the loss of soil st...

Introduction: Water resources quality assessment of the dam sites is one of the primary studies in the designing of these structures. The main challenges in Iran are the reduction of water resources and the limitation of groundwater exploitation. Much of these resources are formed in karst water resources in the karstic susceptible formations such...

Decreasing reservoir pressure caused by hydrocarbon exploitation is one of the major problems related to oil reservoirs. In order to maintain the current production rate the lost energy should be compensated. Gas injection is a common method for increasing reservoir pressure and is mainly used in SW Iranian oil fields. Reactivation of pre-existing...

Mineralogical and textural characteristics of rock materials have an important influence on the physico_mechanical properties. In the present study, the statistical mean of the geometric textural parameters besides the total constituent grains, for the main minerals phases (quartz, plagioclase, alkali-feldspar) and mafic minerals (here all the othe...

The geotechnical parameters and permeability of the Bazoft dam site were investigated. The bedrock of the Bazoft dam site belongs to the Asmari and Jahrum (Eocene, Oligocene and Miocene) formations. Rock mass rating (RMR) and geological strength index (GSI) classification systems were used to evaluate the dam site. Physical, mechanical and dynamic...

The determination of brittleness and geomechanical parameters, especially uniaxial compressive strength (UCS) and Young's modulus (ES) of rocks are needed for the design of different rock engineering applications. Evaluation of these parameters are time-consuming processes, tedious, expensive and require well-prepared rock cores. Therefore, compres...

The present study describes a remote sensing approach for preparing lineament map that subsequently indicates the influence of lineament density in the severity of weathering development. In this study, SPOT-5 data, the integration of SPOT-ASTER and Digital Elevation Model (DEM) data were used and processed. The existence of an active fault system...

Due to the importance of uniaxial compressive strength (UCS), static Young's modulus (ES) and shear wave velocity, it is always worth to predict these parameters from empirical relations that suggested for other formations with same lithology. This paper studies the physical, mechanical and dynamical properties of limestone rocks using the results...

An experimental study that contributes to the understanding of the relationships between petrographic features and engineering properties of igneous rocks is conducted. To this end, a wide range of igneous rocks were tested for their engineering properties including abrasivity (Cerchar abrasivity index), mechanical (point load strength index Is(50)...

Subsurface stratigraphy has recently been a subject of intense research within the last two decades for dealing with the complicated nature of subsurface ground layers through building three-dimensional geological models. Considering the importance of subsurface soil characterization in urban areas in geotechnical and geological engineering project...

This research was carried out to determine the influence of rainfall intensity and soil physico-chemical properties on erosion behavior of 11 representative soil samples from the badlands of the Dahanghale area in northeastern Iran. Soil textures were loamy to silty loamy, with a very heterogeneous surface gravel and vegetation cover. The research...

مشخصات پتروگرافیکی همچون بافت، کانی‌شناسی و ریزساختار، اثری بنیادی بر ویژگی‌های فیزیکی و کیفی مصالح دارد. بسیاری از معیارهای طبقه‌بندی بنیادی یا انتخاب کیفی مصالح برای کاربردهای صنعتی بر مبنای ویژگیهای بافتی- کانی‌شناسی و شیمیایی تعیین می‌شوند. آگاهی از اهمیت و درک ارتباط متقابل انواع مؤلفه‌های بافتی، کانی‌شناسی و شیمی‌بلورها می‌تواند در پیشگویی رف...

This study aims at developing a systematic and holistic logical decision-making model to assess technical feasibility of reclaimed water reuse in agriculture. The hypothesis of algorithm was based on the basic conditions recommended by Food and Agriculture Organization of the United Nations which are required to make irrigated farming a success. Th...

Seepage through foundation and abutments of a dam can potentially result in waste of the water stored in dam reservoir, erosion of foundation materials, and development of uplift pressure in dam foundation which, consequently, threatens long-term stability of Dam. Grouting process, which is carried out based on the results of Lugeon test, is consid...

Thorough and realistic performance predictions are among the main requisites for estimating excavation costs and time of the tunneling projects. Also, NTNU/SINTEF rock drillability indices, including the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), and Cutter Life Index™ (CLI), are among the most effective indices for determining rock drillab...

For determination of the in-situ deformation modulus of rock mass at Bakhtiari Dam site, located in south-west of Iran, plate jacking tests (PJT) and dilatometer tests (DLT) carried out during the geotechnical investigations. In this study, the results of PJTs and DLTs were compared. This comparison involves 89 vertical and horizontal PJTs and 83 D...

Precisely investigating subsurface conditions is a major concern for both geotechnical and geological engineers. In recent years, growing urbanization and construction of high-rise buildings in Mashhad City, Iran, have increased the demand for 3D models as a basis for subsurface characterization. In this regard, this study deals with the developmen...

Soil liquefaction is among the secondary earthquake effects. This phenomenon, which was widely seen in Astaneh-ye Ashrafiyeh during the 1990 Manjil-Rudbar earthquake, led to considerable damage. The present study was conducted to assess the future re-liquefaction hazard and risk and prepare liquefaction hazard map of the study area. For this purpos...

Gypseous soils are considered problematic when used as the foundation in civil engineering structures such as roads, buildings and dams. Solubility is the main problem of gypseous soils. These soils are resistant and have good engineering properties in dry state. However, when saturated by rainwater or due to rising groundwater table, the soluble m...

Mechanized tunneling through clayey formations is threatened by encountering the clogging problem. Adhesion stress, as the tendency between clay and a metal surface, leads to clogging between TBM and excavated materials. Some empirical clogging classification charts were prepared based on the experienced clogging problems. Moreover, experimental at...

This paper, demonstrated a scientific approach to prepare a geomechanical model for Bangestan reservoir in an oil well in the south-west of Iran. Bangestan is one of the most important oil reservoirs in the Middle-East that its geomechanical characters are not perfectly known. Moreover, unexpected problems such as casing collapse, production drop a...

This paper sheds further light on the fundamental relationships between simple methods, rock strength, and brittleness of igneous rocks. In particular, the relationship between mechanical (point load strength index Is(50) and brittleness value S20), basic physical (dry density and porosity), and dynamic properties (P-wave velocity and Schmidt rebou...

The main purpose of this study is to introduce the geological controlling factors in improving an intelligence-based model to estimate shear wave velocity from seismic attributes. The proposed method includes three main steps in the framework of geological events in a complex sedimentary succession located in the Persian Gulf. First, the best attri...

Seepage through foundation and abutments of a dam can potentially result in waste of the water stored in the dam reservoir, erosion of foundation materials, and development of uplift pressure in the dam foundation which, consequently, threatens the long-term stability of dam. A grouting process, which is carried out based on the results of the Luge...

ارتباط بين ويژگي‌هاي هندسي بافتي با ويژگي‌هاي مقاومتي از ده‌ها سال پيش توسط محققين مختلف بررسي و روابط متفاوت و بعضاً ضدونقيضي ارائه گرديده است. در اين تحقيق مقاطع ميکروسکوپي 15 گروه مختلف سنگ‌هاي آذرين مورد آناليز تصويري و کمينه‌سازي پتروگرافيکي واقع و بانک داده بزرگي از اندازه‌گيري‌هاي هندسي بافتي مشتمل بر حدود 18000 عدد کاني ايجاد گرديد. مهم‌تري...

Purpose – The purpose of this study is to develop a new classification system for corrosive soils by considering the most effective factors of metal corrosion in soil environments. Design/methodology/approach – The classification is based on valuing each factor as its different range effects on soil corrosion. Finally, according to this classificat...

The tendency of clay particles to stick other surfaces means it is adhesive and can cause clogging of tunnel boring machines. Clogging arising from adhesion hinders or halts tunneling operations. The nature of adhesion in the interaction of soil and metal surfaces must be clarified in order to control its occurrence. This paper investigates the adh...

Permeability of rock mass is one of the important issue that should be considered for controling the leakage in the design and construction of dam site. Therefore, in this study to evaluate the permeability of rock mass in the left bank of the kucheri dam the lugean test results from exploratory boreholes were used. Base on the the results of explo...

In this study a fast and simple method with high accuracy to modal analysis determination of rocks is presented. For this purpose modal analysis of three igneous rock samples (Natanz monzogranite, Takab granodiorite and Natanz diorite) using JMicroVision software, on the scanned images of thin sections from these rocks determined. Considering to te...

In this paper the effects of physical properties of Quaternary deposits on the strength parameters of soil are studied in north of Esfahan. The soil samples are classified as GM according to the Unified Soil Classification System. The samples were well graded with dry density ranges between 1.77 and 1.95 g/cm3 and moisture content ranges between 5....

The present paper examines the sedimentary environment and geotechnical features of Quaternary deposits in Isfahan City, Iran. The study divides the sedimentary deposits into five zones on the basis of geological, geomorphological, sedimentological, hydrogeological, and geotechnical data. The zones are as follows: the alluvial fan zone (AFZ), upper...

A systematic estimation of the amount of tool wear is nearly impossible because there is no universally accepted test for determining soil abrasiveness. Laboratory devices that have been developed in recent years have fewer limitations than older methods, but they are unique and are under development. A new device has been developed and used at the...

Zagros zone is the most important geo-structural zone of Middle East in which many developing major cities, like Shiraz, Ahwaz, Bandar Abbas and Kermanshah in Iran and Sulaymaniyah and Erbil in Kurdistan Region (North East of Iraq) have been constructed. Many structures will be planned and constructed in the near future over and under the ground, s...

شن و ماسه مصالح مورد نیاز در عملیات ساختمانی، بتن سازی و بخصوص پروژه­های راه­سازی می باشد. بیشترین برداشت مصالح مورد نیاز از بستر رودخانه­ها و مصالح طبیعی صورت می­پذیرد. اما این برداشت­های بی­رویه باعث بروز مشکلات بیشماری در اکوسیستم و طبیعت گردیده است به طوری که امروزه برداشت مصالح رودخانه­ای در بسیاری از شهرها و کشورهای جهان ممنوع شده است. از این...

Microtremor survey is achieved in order to evaluate the dynamical characteristics of surface layers. For this purpose, 13 trenches were selected and microtremor measurements were performed at the top and bottom of each trench. Floor spectral ratio (FRS) analysis was accomplished to obtain frequency and amplification of the trenches. The results of...

Drilling, blasting and mechanical methods using road headers or tunnel boring machines (TBMs) are among the methods used for underground excavation of rock and soil. The interaction between the tools used and the ground leads to fragmentation of rocks and soil grains as well as tool wear. Wear is defined as the loss of tool material as a result of...

Distinctive characteristics of inverted structures make them important criteria for the identification of certain structural styles of folded belts. The interpretation of 3D seismic reflection and well data sheds new light on the structural evolution and age of inverted structures associated to the Hendijan-Nowrooz-Khafji Fault within the Persian G...

قابلیت فشردگی(Compressibility) توده خاک یکی از مهمترین پارامترهای خاک می¬باشد که برای طراحی¬های ژئوتکنیک ضروری است. با توجه به اینکه تعیین شاخص قابلیت فشردگی از آزمایش تحکیم نسبتا وقت¬گیر است محاسبه این شاخص از فرمول¬های تجربی بر اساس خصوصیات خاک می¬تواند مفید باشد. در طی دهه¬های اخیر، چندین رابطه تجربی برای تخمین قابلیت فشردگی با استفاده از پارامت...

Shear wave velocity, Vs, is one of the important input parameters in seismic response analysis of the ground. Various methods have been examined to measure the soil Vs directly. Direct measurement of Vs is time consuming and costly, therefore many researchers have been trying to update empirical relationships between Vs and other geotechnical prope...

Background and aims: Nowadays, air pollution is considered as one of the most important problems of urbanization and industrial life and all members of the society is affected by this problem. Cement industry is one of the key industries in developing countries with wide application in various projects. However, the industry is considered as one of...

بررسی تنوع بافتی کانی شناسی و اثر آنها روی رفتار های مقاومتی هدف این تحقیق بوده است. 15 تیپ مختلف سنگ آذرین بلورین که از نظر مهندسی عمران گرانیت تلقی میشوند پس از مغزه گیری و تعیین مقاومت فشارشی و کششی اقدام به تهیه مقاطع میکروسکوپی نورگذر گردید. مقاطع تهیه شده تماما بطور موزائیک در سه لایه مختلف بر اساس وضعیت نور پلاریزه تصویر برداری شدند. پس از پ...

Destructuring coefficient is an index that shows effect of geological history and sedimentary processes on formation of fabric and structure in fine soils. In this research, the necessary studies for determining destructuring coefficient in Kerman city deposits were done by the behavior of natural and reconstituted soils. Thus, at first, reconstitu...

The adhesion of clay minerals to metal surfaces leads to clogging of equipment during mechanized tunneling through clay-bearing formations. Among proposed methods to measure adhesion and evaluate clogging potential, Piston Separation Device is found practical and capable to develop. The Device was redesigned based on literature and built in this st...

Rock elastic properties such as Young's modulus, Poisson̕ s ratio, plays an important role in various stages upstream of such as borehole stability, hydraulic fracturing in laboratory scale for observing mechanical properties of the reservoir rock usually using conventional cores sample that obtained from underground in reservoir condition. This me...

Friction angle

The objective of this research is to assess the seepage problems in the Ghordanloo dam foundation and to present a proper method of water-proofing. The dam will be built on the Atrak river in the northeast of Iran. The abutments of this dam will be contructed on limestone and shale that belong to the lower Cretaceous. The maximum thickness of the a...

ABSTRACT Presentation of empirical equations for estimating engineering properties of soils is a simple, low cost and widely-used method. One of the major concerns in using these equations is evaluating their accuracy in different conditions and regions which often leads to doubts about obtained results. Most of these equations were derived in s...

In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using engineering geological mapping of 1961 meters of the scanline, experiments on intact rock samples and measuring P-wave velocity (Vp) for 177...

Clogging occurs during mechanical tunneling with a Tunnel Boring Machine (TBM) because of adhesion of clayey soils to the cutter head and conveyor system. The present study examined the effects of water and sand contents on clogging in Montmorillonite clayey soil. Testing was carried out using an adhesion test device on 28 samples with different wa...

در این مقاله با استفاده از آنالیزهای آماری به بررسی میزان تأثیر عوامل مختلف بر روی خوردگی فلزات در خاک پرداخته ‌شده است. به دلیل عدم وجود داده‌‌های مشابه در کشور که بتواند تأثیر هر عامل را بر روی خوردگی فلزات مدفون مشخص نماید، از داده‌های حاصل از آزمایش‌های صورت گرفته توسط سازمان ملی استانداردهای امریکا بر روی خورندگی فلزات در خاک بین سال‌های 1922...

بمنظور ارزیابی قابلیت اعتبار داده های چکش اشمیت ماخذ از سطوح با زبری متفاوت 1350 مورد آزمون اندازه گیری سختی واجهشی چکش اشمیت روی سه نوع سطوح با مورفولوژی و زبری سطح متفاوت حاصل از 15 تیپ مختلف سنگ آذرين متبلور (گرانيت تا گابرو) انجام گردید. نتایج آزمون از حداقل 30 رکورد چکش اشمیت نوع L بروی سه نوع نمونه اخذ گردید: 1) نمونه های بلوکی با سطوح صاف حا...

Solubility is the main problem of gypseous soils. In dry state, these soils are resistant and have good engineering properties. However, when saturated by rainwater or rising groundwater table, the minerals in these soils are washed out, making the structures built on them prone to subsidence. In the recent decades, buildings constructed in souther...

The seismotectonic provinces are the basis of many seismology studies in a given area. The seismotectonic provinces, in which the seismic activity is distributed homogenously and lay in same tectonically and geologically region, are used as the basic maps in seismology studies and preparation of seismic hazard maps. In the last decays, the seismolo...

In the present study, a new model is proposed to predict the permeability per fracture in the fault zones by a new parameter named joint hydraulic factor (JH). JH is obtained from Water Pressure Test (WPT) and modified by the degree of fracturing. The results of JH correspond with quantitative fault zone descriptions, qualitative fracture, and faul...

Current advances in science, followed by development of excavation equipments technology resulted in growth of tunnelling projects for different purposes. In spite of conducting exploratory studies prior to these projects, in some cases due to of impassable paths, the studies are limited to certain areas. Hence, during geotechnical studies, it is p...

The purpose of this study is The Study on Karst Morphology Forms in Manjil Region of Gilan Province. Due to geological features and quantity and type of rainfalls in Gilan Province and other effective factors on formation and development of Karst and Karst water resources, it is necessary to study karst morphology forms of this region. This study h...