En
  • دکتری (1392)

    مکانیک سنگ

    دانشگاه تربیت مدرس، تهران، ایران

  • کارشناسی‌ارشد (1387)

    مکانیک سنگ

    تربیت مدرس، تهران، ایران

  • کارشناسی (1385)

    مکانیک سنگ

    صنعتی اصفهان، اصفهان، ایران

  • دینامیک سنگ
  • مکانیک شکست
  • طراحی فضاهای زیرزمینی
  • آزمایشگاه مکانیک سنگ

    زمینه های پژوهشی: انجام آزمایش های مکانیک سنگ

    کارشناس مسئول: مهندس شیخانی

    هیات علمی همکار: حمید رضا نجاتی

    تلفن: 82883507

    مکان: بلوک 6 طبقه 1 غربی اتاق 16-6

  • آزمایشگاه مدلسازی فیزیکی

    زمینه های پژوهشی: مدلسازی فیزیکی، انجام آزمایش های غیر مخرب و آزمایش برش مستقیم

    کارشناس مسئول: مهندس شیخانی

    هیات علمی همکار: حمید رضا نجاتی

    تلفن: 82883507

    مکان: ضلع جنوبی بلوک 6 طبقه -1

  • آزمایشگاه خزش

    زمینه های پژوهشی: انجام آزمایش خزش و مطالعه رفتار وابسته به زمان سنگ ها

    کارشناس مسئول: مهندس شیخانی

    هیات علمی همکار: حمید رضا نجاتی

    تلفن: 82883507

    مکان: ضلع جنوبی بلوک 6 طبقه -1

  • کارگاه مکانیک سنگ

    زمینه های پژوهشی: مغزه گیری و آماده سازی نمونه برای انجام آزمایش

    کارشناس مسئول: مهندس شیخانی

    هیات علمی همکار: حمید رضا نجاتی

    تلفن: 82883507

    مکان: ضلع جنوبی بلوک 6 طبقه -1

  • آزمایشگاه مدلسازی عددی

    زمینه های پژوهشی: مدلسازی عددی

    کارشناس مسئول: مهندس شیخانی

    هیات علمی همکار: حمید رضا نجاتی

    تلفن: 82883507

    مکان: بلوک 6 طبقه دوم شرقی اتاق 11-6

دکتر حمیدرضا نجاتی، متولد کاشان، 1362، دانش آموخته ممتاز کارشناسی مهندسی معدن از دانشگاه صنعتی اصفهان و کارشناسی ارشد و دکتری مهندسی مکانیک سنگ از دانشگاه تربیت مدرس می باشد. دکتر نجاتی در سال 1391 موفق به اخذ بورسیه تحصیلی از دانشگاه تربیت مدرس شد و در سال 1393 به عنوان عضو هیات علمی دانشگاه تربیت مدرس شروع به کار نمود. از سوابق علمی - اجرایی دکتر نجاتی می توان به موارد زیر اشاره نمود: عضو هیات مدیره انجمن علمی مکانیک سنگ (1393 تا 1400)، مدیر گروه مکانیک سنگ دانشگاه تربیت مدرس (1398 تا 1400) و معاون آموزشی دانشکده فنی و مهندسی (از 1399 تا اکنون) اشاره نمود. زمینه تحقیقاتی دکتر نجاتی مطالعه مکانیزم شکست سنگ ها تحت بارهای دینامیک می باشد. دکتر نجاتی سوابق اجرایی متعددی در زمینه طراحی و تحلیل فضاهای زیرزمینی و تحلیل پایداری شیروانی های سنگ و خاکی دارند و در پروژه های متعدد عمرانی، معدنی و نفتی با بخش صنعت همکاری داشته اند.

ارتباط

رزومه

Investigation of the Effect of Using Sungun Copper Mine Tailings Instead of Fine-Grained Materials in Concrete Construction on Mechanical Properties and Heavy Metal Leakage

Ahad Barzegar Ghazi, Ahmad Jamshidi, Hamid Reza Nejati
Journal PapersJournal of Mineral Resources Engineering , 2021 February 22, {Pages }

Abstract

The large volume of mine tailings as well as the considerable concentration of toxic pollutants, resulted from mining activities, cause irreparable damage to the surrounding environment. The leakage of toxic elements from the mine tailings to the environment is considered as a crucial issue. The reuse of mine tailings in concrete industry is considered as one of the main management techniques to reduce their probable adverse effects. In this study, the tailings of Sungun copper mine were collected to investigate their applicability in concrete construction instead of fine-grained materials. The results revealed that the concentrations of copper, arsenic, lead, chromium, cobalt, and nickel in copper mine tailings were higher than the environ

Estimating groundwater inflow into Dorud-Khorramabad railway tunnel using analytical and numerical methods

Ebrahim Ghorbani, Saleh Ghadernejad, Dorna Emami, Hamidreza Nejati
Journal PapersInternational Journal of Mining and Geo-Engineering , 2021 April 5, {Pages }

Abstract

The main objective of this study is to estimate the amount of groundwater inflow into Dorud-Khorramabad railway tunnel. To this end, at first place, existing approaches of predicting of groundwater inflow into tunnel was reviewed. According to the literature, up to know, a wide range of approaches have been proposed in order to predict the groundwater inflow into tunnel which can be classified into three distinct group including analytical solutions, empirical equations, and numerical modeling. Analytical solution and empirical equations are mainly developed based on the given hypotheses and specific date sets, respectively, and should be applied just in similar conditions. On the other hand, results obtained from numerical modeling are gen

Prediction of safety factors for slope stability: comparison of machine learning techniques

A Mahmoodzadeh, M Mohammadi, H Farid Hama Ali, H Hashim Ibrahim, ...
Journal Papers , , {Pages }

Abstract

Predicting construction time and cost of tunnels using Markov chain model considering opinions of experts

A Mahmoodzadeh, M Mohammadi, SN Abdulhamid, HR Nejati, ...
Journal Papers , , {Pages }

Abstract

Monitoring of fracture propagation in brittle materials using acoustic emission techniques-A review

Hamid Reza Nejati, Amin Nazerigivi, Mehrdad Imani, Ali Karrech
Journal PapersComputers and Concrete , Volume 25 , Issue 1, 2020 January 1, {Pages 15 }

Abstract

During the past decades, the application of acoustic emission techniques (AET) through the diagnosis and monitoring of the fracture process in materials has been attracting considerable attention. AET proved to be operative among the other non-destructive testing methods for various reasons including their practicality and cost-effectiveness. Concrete and rock structures often demand thorough and real-time assessment to predict and prevent their damage nucleation and evolution. This paper presents an overview of the work carried out on the use of AE as a monitoring technique to form a comprehensive insight into its potential application in brittle materials. Reported properties in this study are crack growth behavior, localization, damage e

Study of damage zone around a circular opening using acoustic emission technique

Morteza Ahmadi, Ali Dadi-givshad, Hamid Reza Nejati
Journal PapersJournal of Mining and Environment , 2020 February 20, {Pages }

Abstract

One of the methods used to investigate the damaged zone in rock structure is the acoustic emission method. This method is based on receiving the elastic waves that are produced by deformation and cracking of the rock mass around the underground excavation. In this research, a study is conducted on the rock samples by a numerical method to investigate the damaged zone caused by the excavation of circular space on it. For this purpose, 33 cube samples of three different material types including sandstone, concrete, and cement-plaster mortar are prepared. A circular hole is drilled in the center of each sample. The hole diameter is 20 or 25 mm. The samples are loaded uniaxially or biaxially with different stress rates. It is tried to study the

A new rock brittleness index on the basis of punch penetration test data

Saleh Ghadernejad, Hamid Reza Nejati, Saffet Yagiz
Journal PapersGeomechanics and Engineering , Volume 21 , Issue 4, 2020 January , {Pages 391-399 }

Abstract

Brittleness is one of the most important properties of rock which has a major impact not only on the failure process of intact rock but also on the response of rock mass to tunneling and mining projects. Due to the lack of a universally accepted definition of rock brittleness, a wide range of methods, including direct and indirect methods, have been developed for its measurement. Measuring rock brittleness by direct methods requires special equipment which may lead to financial inconveniences and is usually unavailable in most of rock mechanic laboratories. Accordingly, this study aimed to develop a new strength-based index for predicting rock brittleness based on the obtained base form. To this end, an innovative algorithm was developed in

On the applicability of some indirect tests for estimation of tensile strength of anisotropic rocks

Fuad Rastegar, Hamid Reza Nejati, Abdolhadi Ghazvinian, Mir Raouf Hadei, Amin Nazerigivi
Journal PapersJournal of Mining and Environment , 2020 March 7, {Pages }

Abstract

The tensile strength of rocks plays a noteworthy role in their failure mechanism, and its determination can be beneficial in optimizing the design of the rock structures. Schistose rocks due to their inherent anisotropy in different foliation directions show a diverse strength at each direction. The purpose of this work was to compare and assess the tensile strength of phyllite, which was obtained in direct and indirect tensile tests in different foliation directions. To this end, several phyllite specimens with different foliation angles (0?, 30?, 45?, 60?, and 90?) related to the loading axis (β) were prepared. Finally, the direct tensile test, diametrical and axial point load tests, Brazilian test, and Schmidt hammer test were conducted

Prediction of shear strain induced by blasting waves in surface structures based on coupled frequency, velocity, and displacement effects

Reza Nateghi, Kamran Goshtasbi, Hamid Reza Nejati
Journal PapersJournal of Vibration and Control , 2020 June 17, {Pages 1.0775463209e+15 }

Abstract

Blasting ground vibration is an undesirable side effect of using explosives to fragment rocks. There is not any universally accepted standard to determine limitations of blast vibrations; however, velocity is the most commonly used method to measure ground vibrations. Because the structural response is highly frequency dependent, the frequency content is an essential characteristic of blast-induced shock waves along with the velocity. The magnitude of blast-induced displacement or velocity and their relative stress and strain are directly related to the quantity of charge, distance from blasting point, and geological conditions. These effects were not considered in the response spectrum theory of structures. This article tries to propose a

Study of Damaged Zone around Circular Opening Using Acoustic Emission Technique

A Dadi-givshad, M Ahmadi, Hamid Reza Nejati
Journal PapersJournal of Mining and Environment , Volume 11 , Issue 2, 2020 April 1, {Pages 433-451 }

Abstract

One of the methods used to investigate the damaged zone in rock structure is the acoustic emission method. This method is based on receiving the elastic waves that are produced by deformation and cracking of the rock mass around the underground excavation. In this research, a study is conducted on the rock samples by a numerical method to investigate the damaged zone caused by the excavation of circular space on it. For this purpose, 33 cube samples of three different material types including sandstone, concrete, and cement-plaster mortar are prepared. A circular hole is drilled in the center of each sample. The hole diameter is 20 or 25 mm. The samples are loaded uniaxially or biaxially with different stress rates. It is tried to study the

Coupled Effects of Confining Pressure and Loading Rate on the Mechanical Behavior of Plastic Concrete

Reza Nateghi, Kamran Goshtasbi, Hamid Reza Nejati
Journal PapersJournal of Materials in Civil Engineering , Volume 32 , Issue 10, 2020 October 1, {Pages 04020292 }

Abstract

Plastic concrete is used widely in the construction of cut-off walls. These structures might be exposed to coupled effects of dynamic load along with confining pressure. Therefore, careful study of the impacts of these combined stress conditions is one of the primary issues to be considered in analysis and design. Although there is a large number of experiments on the mechanical properties of plastic concrete in static loading and triaxial condition, none have studied the behavior of this material in dynamic state loading. Therefore, a series of unconfined and triaxial compression tests has been carried out under different confining pressures and strain rates to experimentally investigate the behavior of this material under combined stress

A new development cracked chevron notched direct tension method for determining the mode I fracture toughness of rocks

Mir Raouf Hadei, Neda Akbarlou, Hamid Reza Nejati
Journal PapersTheoretical and Applied Fracture Mechanics , 2020 October 27, {Pages 102811 }

Abstract

A new development has been proposed to measure the tensile fracture toughness (KIc) of rocks. An innovative configuration of chevron notch was applied acting as a cracked chevron notched direct tension (CCNDT) method to determine the mode I fracture toughness, which also could be suggested as a direct method to specify the tensile fracture toughness. In this method, the initial crack is generally created in the form of a chevron notch by a simple rotary saw, and afterward, the crack is subjected to the direct tensile load. Using the chevron notch in the desired specimen is mainly due to the advantages of the sub-critical crack growth in brittle materials. In the present study, a new expression is proposed to calculate the fracture toughness

Use of rock microscale properties for introducing a cuttability index in rock cutting with a chisel pick

Kavosh Rostami, Jafar Khademi Hamidi, Hamid Reza Nejati
Journal PapersArabian Journal of Geosciences , Volume 13 , Issue 18, 2020 September , {Pages 12-Jan }

Abstract

Accurate estimation of rock cuttability is crucial for selecting and design of mechanical excavators in mining and civil engineering practices. This study is to introduce the intact rock cuttability index (IRCI) using three simple and easily accessed intact rock microscale parameters. Assuming that an intact rock consists of mineral grains (materials), cement or matrix and pores, three parameters of rock texture coefficient (TC), Cerchar abrasivity index (CAI), and porosity were selected to be included in IRCI equation. Small-scale rock cutting tests with a simple chisel pick were conducted on very low to medium strength rock specimens to calculate the specific energy (SE) as an indicator of rock cuttability. Accordingly, the correlations b

A practical approach for seismic risk assessment of underground structures: A case study of Iranian subway tunnels

Mohammad Khosrotash Arsham Moayedifar, Hamid Reza Nejati, Amin Nazerigivi
Journal PapersEarthquake Science , Volume 32 , Issue 2, 2020 January , {Pages 64-71 }

Abstract

Determination of plastic concrete behavior at different strain rates to determine Cowper-Symonds constant for numerical modeling

Reza Nateghi, Kamran Goshtasbi, Hamid Reza Nejati
Journal PapersComputers and Concrete , Volume 26 , Issue 3, 2020 January , {Pages 227-237 }

Abstract

Strain rate investigations are needed to calibrate strain-rate-dependent material models and numerical codes. An appropriate material model, which considers the rate effects, need to be used for proper numerical modeling. The plastic concrete cut-off wall is a special underground structure that acts as a barrier to stop or reduce the groundwater flow. These structures might be subjected to different dynamic loads, especially earthquake. Deformability of a structure subjected to dynamic loads is a principal issue which need to be undertaken during the design phase of these structures. The characterization of plastic concrete behavior under different strain rates is essential for proper designing of cut-off walls subjected to dynamic loads. T

On the effect of grain size on rock behavior under cyclic loading by distinct element method

ابوالفضل دلیرنسب, کامران گشتاسبی, کامران, نجاتی
Journal Papersروش های تحلیلی و عددی در مهندسی معدن , Volume 10 , Issue 25, 2020 December 21, {Pages 23-32 }

Abstract

It is well-known that the mechanical behavior of rocks under cyclic loading is much different from static loading conditions. In most constructions, the load applied to structures is within dynamic ranges. That’s why a great deal of attention has been paid to this field to identify the dynamic behavior of rocks in more detail. Nevertheless, the nature of dynamic failure in rocks has not yet been identified, particularly when it comes to cyclic loading The purpose of this study was to investigate the influence of grain size on the mechanical behavior of rocks under cyclic loading using numerical modeling by UDEC. A total of three grain-categories with a diameter of 1, 2, and 4 mm were modeled in the software. All models were of Brazilian t

On Applicability of Some Indirect Tests for Estimation of Tensile Strength of Anisotropic Rocks

F Rastegar, HR Nejati, A Ghazvinian, MR Hadei, A Nazerigivi
Journal Papers , , {Pages }

Abstract

Monotoring of fracture propagation in brittle materials using acoustic emission techniques-A review

HR Nejati, A Nazerigivi, M Imani, A Karrech
Journal Papers , , {Pages }

Abstract

Numerical simulations of fracture shear test in anisotropy rocks with bedding layers

Hadi Haeri, Vahab Sarfarazi, Zheming Zhu, Hamid Reza Nejati
Journal PapersADVANCES IN CONCRETE CONSTRUCTION , Volume 7 , Issue 4, 2019 June 1, {Pages 241-247 }

Abstract

In this paper the effect of bedding layer on the failure mechanism of rock in direct shear test has been investigated using particle flow code, PFC. For this purpose, firstly calibration of pfc2d was performed using Brazilian tensile strength. Secondly direct shear test consisting bedding layer was simulated numerically. Thickness of layers was 10 mm and rock bridge length was 10 mm, 40 mm and 60 mm. In each rock bridge length, bedding layer angles changes from 0 degrees to 90 degrees with increment of 15 degrees. Totally 21 models were simulated and tested. The results show that two types of cracks develop within the model. Shear cracks and tensile cracks. Also failure pattern is affected by bridge length while shear strength is controlle

Seismic fragility and risk assessment of an unsupported tunnel using incremental dynamic analysis (IDA)

Arsham Moayedifar, Hamid Reza Nejati, Kamran Goshtasbi, Mohammad Khosrotash
Journal PapersEarthquakes and Structures , Volume 16 , Issue 6, 2019 June , {Pages 705-714 }

Abstract

Seismic assessment of underground structures is one of the challenging problems in engineering design. This is because there are usually many sources of uncertainties in rocks and probable earthquake characteristics. Therefore, for decreasing of the uncertainties, seismic response of underground structures should be evaluated by sufficient number of earthquake records which is scarcely possible in common seismic assessment of underground structures. In the present study, a practical risk-based approach was performed for seismic risk assessment of an unsupported tunnel. For this purpose, Incremental Dynamic Analysis (IDA) was used to evaluate the seismic response of a tunnel in south-west railway of Iran and different analyses were conducted

دروس نیمسال جاری

  • دكتري
    آمار و احتمالات پيشرفته ( واحد)
    دانشکده فنی و مهندسی، گروه مكانيك سنگ
  • كارشناسي ارشد
    تحليل ديناميك فضاهاي زيرزميني ( واحد)
  • كارشناسي ارشد
    طراحي و اجراي فضاهاي زير زميني ( واحد)

دروس نیمسال قبل

  • كارشناسي ارشد
    مباني طراحي و تحليل فضاهاي زيرزميني ( واحد)
    دانشکده فنی و مهندسی، گروه مكانيك سنگ
  • كارشناسي ارشد
    طراحي و اجراي فضاهاي زير زميني ( واحد)
  • كارشناسي ارشد
    زمين شناسي مهندسي پيشرفته ( واحد)
  • 1397
    كريمي اغسقالي, جواد
    بررسي رشد ترك خستگي در سنگ تحت بارگذاري تركيبي
  • 1397
    دالوند, مصطفي
  • 1397
    ظفري كلوخي, مجيد
  • 1397
    فرجي, پيمان
  • 1398
    اعتمادي, سكينه
  • 1398
    كربلا, محمدمهدي
  • 1397
    خاني, جعفر
    بررسي رفتار مكانيكي بتن هاي پودري واكنش پذير و كاربرد آن به عنوان شاتكريت
  • عضو هیات مدیره انجمن مکانیک سنگ، 1393 تا اکنون
  • مدیر گروه مکانیک سنگ، 1398 تا اکنون
    داده ای یافت نشد

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