Hem Bahadur Motra
@geotechnics.ifg.uni-kiel.de
Lecturer, Geomechanics, Rock Mecahnics and Geotechnical Engineering
University of Kiel
I currently work as a academic staff at the institute of geoscience Kiel University, Germany. My research is mainly driven by my curiosity about the reliable engineering computing, structural reliability, risk and hazard analysis, quality evaluation of models, geostatistics, probabilistic methods, physical processes control rock material behaviour in the subsurface, along with the direct relevance of this field to socially relevant issues, such as mining, nuclear disposal, geotechnical engineering, geo-energy and oil production.
I am a leading academic and researcher in geomechanics, rock mechanics, mining geomechanics, and engineering geology, with a strong international profile in both teaching and research. I have published over 50 peer-reviewed journal papers and hold an h-index of 15, reflecting my substantial impact on the field. I have taught and supervised B.Sc., M.Sc., and PhD theses across core geotechnical subjects.
EDUCATION
PhD in Geotechnical Engineering
RESEARCH, TEACHING, or OTHER INTERESTS
Geotechnical Engineering and Engineering Geology, Civil and Structural Engineering, Safety, Risk, Reliability and Quality, Renewable Energy, Sustainability and the Environment
FUTURE PROJECTS
How Important is Compositional Layering within the Earth? Testing the Hypothesis using Seismic Anisotropy
Seismological observations indicate that large regions within Earth show directionally dependent seismic wave speeds. Such seismic anisotropy is a unique and invaluable indicator for geodynamic processes, structure and rheology of the Earth. However, a challenge in using anisotropy is that it arises from different sources, leading to non-unique interpretations of the geodynamic process that give rise to anisotropy. Intrinsic anisotropy originates from single crystals, or aggregates of oriented crystals, which is known as crystallographic preferred orientation (CPO). It is an important source for anisotropy in the deeper parts of the crust, mantle and core. Extrinsic, or apparent, anisotropy arises from geometrical effects such as layering of rocks, and oriented crack and fluid networks. In this project, particular focus is placed on testing the hypothesis that mineral compositional banding is an important contributor to seismic anisotropy throughout the interior of Earth, which has not
Applications Invited
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Farshad Sadeghpour, Hem Bahadur Motra, Chinmay Sethi, Sandra Wind, Bodhisatwa Hazra, Ghasem Aghli, and Mehdi Ostadhassan
Elsevier BV
Chinmay Sethi, Hem Bahadur Motra, Bodhisatwa Hazra, and Mehdi Ostadhassan
Elsevier BV
Bodhisatwa Hazra, Hem Bahadur Motra, James C. Hower, Maria Mastalerz, Chinmay Sethi, and Harold Schobert
Elsevier BV
Bo Liu, Aydin Larestani, Kouqi Liu, Yifei Gao, Hem B. Motra, Abdolhossein Hemmati-Sarapardeh, and Mehdi Ostadhassan
Elsevier BV
Fabio Trippetta, Roberta Ruggieri, and Hem B. Motra
Elsevier BV
Ghasem Aghli, Babak Aminshahidy, Hem Bahadur Motra, Ardavan Darkhal, Farshad Sadeghpour, and Mehdi Ostadhassan
Elsevier BV
Farshad Sadeghpour, Ardavan Darkhal, Yifei Gao, Hem B. Motra, Ghasem Aghli, and Mehdi Ostadhassan
Elsevier BV
R. Punturo, S. Mineo, H.B. Motra, G. Lanzafame, V. Indelicato, G. Pappalardo, and R. Cirrincione
Elsevier BV
Chinmay Sethi, Bodhisatwa Hazra, Mehdi Ostadhassan, Hem Bahadur Motra, Arpan Dutta, J.K. Pandey, and Santosh Kumar
Elsevier BV
Chao Wang, Bo Liu, Mohammad-Reza Mohammadi, Li Fu, Elham Fattahi, Hem Bahadur Motra, Bodhisatwa Hazra, Abdolhossein Hemmati-Sarapardeh, and Mehdi Ostadhassan
Elsevier BV
Henok Hailemariam, Nils Blume, Hem B. Motra, and Frank Wuttke
Informa UK Limited
Bo Liu, Mohammad-Reza Mohammadi, Zhongliang Ma, Longhui Bai, Liu Wang, Zhigang Wen, Yan Liu, Hem Bahadur Morta, Abdolhossein Hemmati-Sarapardeh, and Mehdi Ostadhassan
Elsevier BV
Kouqi Liu, Sirous Hosseinzadeh, Majid Safaei-Farouji, Bo Liu, Hem B. Morta, and Mehdi Ostadhassan
Elsevier BV
Kouqi Liu, Majid Safaei-Farouji, Yifei Gao, Thomas Gentzis, Bo Liu, Hem B. Morta, and Mehdi Ostadhassan
Elsevier BV
Mohammad Hosein Khosravi, Mahdi Kheirollahi, Bo Liu, Thomas Gentzis, Kouqi Liu, Hem B. Morta, and Mehdi Ostadhassan
Elsevier BV
Mohsen Bazargan, Bjarne S. G. Almqvist, Hem Bahadur Motra, Pooyan Broumand, Tobias Schmiedel, and Christoph F. Hieronymus
MDPI AG
Laboratory-based elastic wave measurements are commonly used to quantify the seismic properties of Earth’s crust and upper mantle. Different types of laboratory apparatuses are available for such measurements, simulating seismic properties at different pressure and temperature. To complement such laboratory measurements, we present a numerical toolbox to investigate the seismic properties of rock samples. The numerical model is benchmarked against experimental results from a multi-anvil apparatus, using measurements of a stainless steel calibration standard. Measured values of the mean compressional- and shear-wave velocities at room conditions of the steel block were 6.03 km/s and 3.26 km/s, respectively. Calculated numerical results predicted 6.12 km/s and 3.30 km/s for compressional and shear-wave velocities. Subsequently, we measured Vp and Vs up to 600 MPa hydrostatic confining pressure and 600 °C. These measurements, at pressure and temperature, were then used as the basis to predict numerical wave speeds. There is, in general, good agreement between measurement and predicted numerical results. The numerical method presented in this study serves as a flexible toolbox, allowing for the easy setup of different model geometries and composite materials.
Sascha Zertani, Jan Pleuger, Hem B. Motra, and Timm John
Elsevier BV
Mohsen Bazargan, Hem Bahadur Motra, Bjarne Almqvist, Sandra Piazolo, and Christoph Hieronymus
Elsevier BV
Kim S. Mews, Mustafa M. Alhubail, Luka Hansen, Hem B. Motra, Frank Wuttke, Qiang Ye, Anil Misra, and Reza Barati Ghahfarokhi
American Society of Mechanical Engineers
Abstract The assessment of geomechanical properties of unconventional reservoirs is significant as they assist in placement as well as understanding of the geometry and properties of multi-stage hydraulic fractures in horizontal wells. Severe heterogeneities at micro-scale in addition to possibility of having non-intact samples provide opportunities for using micro-mechanics techniques on drill cutting size samples. This will lead to not only have a continuous log of geomechanical properties on heterogeneous formations but also be able to measure the mechanical properties of non-intact samples accurately. This study presents a multi-scale comparison of the elastic properties such as Young’s modulus and Poisson’s ratio on the Eagle Ford Formation. Peak Force Quantitative Nano-mechanical (PF-QNM) AFM-based technique has been performed and compared with true triaxial testing. A new model for AFM evaluation that corrects Young’s modulus in dependency of Poisson’s ratio has been developed. The results indicate that the distribution of Young’s modulus is separated into two regions, one dominated by brittle minerals indicating higher values and one dominated by ductile rock components resulting in lower values. The findings are significant as PF-QNM testing can be performed where only drill cutting-size samples are available, as it shows strong agreement with the triaxial testing result.
Sascha Zertani, Timm John, Frederik Tilmann, Hem B. Motra, Ruth Keppler, Torgeir B. Andersen, and Loic Labrousse
American Geophysical Union (AGU)
Subduction zone processes and the resulting geometries at depth are widely studied by large‐scale geophysical imaging techniques. The subsequent interpretations are dependent on information from surface exposures of fossil subduction and collision zones, which help to discern probable lithologies and their structural relationships at depth. For this purpose, we collected samples from Holsnøy in the Bergen Arcs of western Norway, which constitutes a well‐preserved slice of continental crust, deeply buried and partially eclogitized during Caledonian collision. We derived seismic properties of both the lower crustal granulite‐facies protolith and the eclogite‐facies shear zones by performing laboratory measurements on cube‐shaped samples. P and S wave velocities were measured in three perpendicular directions, along the principal fabric directions of the rock. Resulting velocities agree with seismic velocities calculated using thermodynamic modeling and confirm that eclogitization causes a significant increase of the seismic velocity. Further, eclogitization results in decreased VP/VS ratios and, when associated with deformation, an increase of the seismic anisotropy due to the crystallographic preferred orientation of omphacite that were obtained from neutron diffraction measurements. The structural framework of this exposed complex combined with the characteristic variations of seismic properties from the lower crustal protolith to the high‐pressure assemblage provides the possibility to detect comparable structures at depth in currently active settings using seismological methods such as the receiver function method.
W. Rabbel, S. Buske, T. Jusri, D. Köhn, J. Lehr, H.B. Motra, L. Schreiter, M. Thorwart, and
European Association of Geoscientists & Engineers
Mahmoud Khalifeh, Arild Saasen, Helge Hodne, and Hem Bahadur Motra
Elsevier BV
Abstract In this work, we have studied selected rheological properties and mechanical properties of rock-based geopolymers. The geopolymers are suggested for zonal isolation and permanent abandonment of hydrocarbon wells. Our viscosity measurements of the geopolymeric slurries shows a very small yield stress and a nearly constant additional viscosity. To find the effect of mechanical vibration, a rotational viscometer was modified by being equipped with a mechanical vibrator. Consistency of the geopolymeric slurry was measured by utilization of atmospheric and pressurized consistometers to find the impact of pressure and temperature on pumpability. The downhole temperature uncertainty was also studied by using atmospheric consistometers. Static-fluid-loss is an issue, which causes loss of hydrostatic pressure. Therefore, static-fluid-loss test was carried out. Strength development of the geopolymeric slurry was measured directly and indirectly by utilization of uniaxial compressive strength and Ultrasonic Cement Analyzers, respectively. As the pre-defined algorithm could not convert the sonic velocity to sonic strength, a custom algorithm was generated. The elastic shear wave and compressional wave velocities and velocity anisotropies of the samples were tried to be determined experimentally. The measurements were conducted on cube-shaped specimens in a triaxial multi-anvil press using the ultrasonic pulse-transmission technique. As it is necessary to study the bond strength between the geopolymers and pipe, steel pipe was used. The shear bond strength between pipe and the rock-based geopolymer was measured.
A. S. Sattari, H. B. Motra, Z. H. Rizvi, and F. Wuttke
Springer International Publishing
In order to determine the change of thermal conductivity of rock solids under coupled thermo-mechanical processes and developed microstructure fractures, an application of a new lattice element method (LEM) with additional interface elements representing the bond between the particles is investigated. The thermo-mechanical loadings in many engineering applications, such as deep geothermal systems, can result in a change of mechanical and thermal properties of rock solids. In the proposed model, the change of thermal conductivity under mechanical loading, thermal expansion and developed fractures due to coupled thermo-mechanical processes are considered. The main advantage of the new model is that it considers the thermal expansion while increasing the compression stresses in particles contact zone, which captures the true stress-strain behavior of the rock sample under coupled processes. The numerical results are eventually compared to the experimental results obtained from multi-anvil apparatus in Laboratory of CAU Kiel. It is shown that the new model is able to estimate the change of thermal conductivity under coupled thermo-mechanical loadings and developed microcracks.