|
|
- Uncertainty modeling and propagation for groundwater flow: a comparative
study of surrogates-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract We compare sparse grid stochastic collocation and Gaussian process emulation as surrogates for the parameter-to-observation map of a groundwater flow problem related to the Waste Isolation Pilot Plant in Carlsbad, NM. The goal is the computation of the probability distribution of a contaminant particle travel time resulting from uncertain knowledge about the transmissivity field. The latter is modelled as a lognormal random field which is fitted by restricted maximum likelihood estimation and universal kriging to observational data as well as geological information including site-specific trend regression functions obtained from technical documentation. The resulting random transmissivity field leads to a random groundwater flow and particle transport problem which is solved realization-wise using a mixed finite element discretization. Computational surrogates, once constructed, allow sampling the quantities of interest in the uncertainty analysis at substantially reduced computational cost. Special emphasis is placed on explaining the differences between the two surrogates in terms of computational realization and interpretation of the results. Numerical experiments are given for illustration.
PubDate: 2024-07-16
DOI: 10.1007/s13137-024-00250-3
- Some remarks on cone-adapted shearlets
-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In recent years, cone-adapted shearlets have been established as a powerful tool for the detection of directional information in images. It has also turned out that an interpretation of cone-adapted shearlets in the realm of coorbit space theory exists. Then, cone-adapted shearlets are defined by requiring a certain sparsity pattern of the frame expansion coefficients. In this note, we discuss some structural properties of these spaces.
PubDate: 2024-07-16
DOI: 10.1007/s13137-024-00251-2
- Influence of uncertain coriolis parameter on wave solution of Korteweg-de
Vries equation-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This article examines the approximate solution of the Geophysical Korteweg-de Vries (GKdV) equation in a fuzzy environment. The Adomian decomposition method (ADM) and ADM-Pade approximation technique have been implemented to solve the governing equation. Environmental or climate changes, along with the propagation of air or water waves, can lead to uncertainties or ambiguities in initial or boundary conditions, as well as in parameter associated with the Coriolis effect. To address these uncertainties, this work aims to find the approximate fuzzy solution to the said physical problem by applying a double parametric approach with the help of ADM. To validate the obtained solution, comparisons are made between the fuzzy solutions and existing precise (crisp) solutions in specific cases. Furthermore, in another scenario involving the fuzzy solution, the ADM-Pade approach is employed. This implementation yields an approximate solution that exhibits higher accuracy and closely resembles a solitary wave solution, demonstrating a rapid convergence rate. The analysis of special cases shows a direct relationship between wave height and the Coriolis parameter and an inverse relationship between wavelength and the Coriolis parameter. Finally, the article includes 2D and 3D graphs, along with plots of fuzzy solutions, to enhance understanding of the fuzzy nature of the solutions.
PubDate: 2024-07-12
DOI: 10.1007/s13137-024-00252-1
- Fast high-frequency porosity characterization from computer tomography
images and deep learning-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This work presents a methodology for combining deep learning with whole-core computed tomography (CT) imaging and laboratory data for fast and high-frequency estimation of porosity logs. The proposed method trains a convolutional neural network (CNN) model to predict laboratory-scale porosities by using core-scale CT images as input. Despite the different scales, the model works well to predict the porosities measured at laboratory scales using the textures present in core-scale CT images. The main contribution of this work is the data-driven methodology for fast and high-frequency characterization of porosity at the core scale. The proposed methodology can provide a much more efficient porosity characterization than the traditional workflow based on the qualitative and subjective evaluation of experts. The method was evaluated in a well-based cross-validation process in 26 wells from 3 different Brazilian pre-salt fields, using two distinct CNN architectures of varying complexity. The results show that the models can make good predictions for new wells with acceptable margins of error. The proposed method can be easily integrated into digital rock workflows as it is based on data available for traditional petrophysical analyses and deep learning models available in open source.
PubDate: 2024-06-10
DOI: 10.1007/s13137-024-00249-w
- Stable computation of analytical expressions for the gravity and magnetic
field response of distant polyhedral targets-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Though implemented through different evaluation strategies, the analytical formulation of the polyhedral gravity and magnetic field response involves some decomposition of the primary volume integrals into a summation of integrals defined over individual polyhedral segments. The existing closed solutions for the latter lead to expressions that relate the computation point to each vertex defining the known polyhedral source. When the distance between the computation point and the polyhedral distribution increases significantly then the numerical evaluation of the analytical formulas fails to produce correct significant digits, due to destructive cancellation in summing that is large compared to the correct result. The present contribution proposes a concept as a solution to this well—documented numerical instability problem. Thereby we prove that the analytical cancellation of the dominant terms before the computation is crucial to decrease the order of complexity to an optimal numerical limit. Our investigations lead to an alternative vectorial method for the evaluation of the gravity anomaly of a polyhedral target. The method is compared to the existing analytical formulation of the vectorial method for different target sizes and distances of the computation point. The performed tests demonstrate the numerical stability of the new approach as well as its superiority in representing gravity anomalies at the \(10^{-11}\) level for distances beyond 100 m.
PubDate: 2024-05-21
DOI: 10.1007/s13137-024-00248-x
- Surface-subsurface filtration transport with seawater intrusion:
multidomain mixed variational evolution problems-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Surface-subsurface filtration transport with seawater intrusion phenomena are formulated and variationally analyzed, as coupled multimedia mixed pairs of free boundary interface problems. Physically, multidomain subsurface mixed velocity-pressure fractional Darcian flow models coupled with surface evolution Stokesian mixed flows are considered. Specifically, two-phase air-fresh water above the sea level and fresh water-seawater characterizations are considered. Internal boundary synchronizing transmission conditions of multidomain nonoverlapping decompositions are modeled in terms of variational Lagrangian dual subpotential maximal monotone inclusions. Similarly, filtration transport coupling interface transmission constraints are implemented by mass flux-velocity-pressure Lagrange dual multipliers as solutions of subpotential subdifferential equations.
PubDate: 2024-03-04
DOI: 10.1007/s13137-024-00245-0
- An analytical model for injectivity tests in multilayered reservoir with
formation crossflow-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Injectivity tests involve injecting fluid through wells into an oil reservoir to gather information about its parameters. This knowledge can be valuable for improving oil production. As such, several studies on injectivity tests in multilayered reservoirs have been conducted. Typically, these studies focus only on commingled systems, which are layers separated by impermeable barriers. The present work developed an analytical model in the Laplace space for multilayered reservoirs under injectivity tests, considering formation crossflow across all layers. The accuracy of the proposed solution was verified by comparing it with a finite difference flow simulator. The results from the analytical model and numerical data are consistently similar. Additionally, the analytical solution’s data is used to estimate the reservoir’s equivalent permeability, which yields satisfactory accuracy for all tested cases.
PubDate: 2024-02-21
DOI: 10.1007/s13137-024-00247-y
- Study of toroidal magnetic field for the flow past a rotating rigid sphere
embedded in the less permeable medium-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This paper represents the exact solution for the properties of the conducting fluid that is flowing past a rotating sphere immersed in a porous medium. It’s a continuation of Sharma and Srivastava (Z Angew Math Mech 103:e202200218, 2022), where the sphere is rotating in the clear fluid region. The solution to the problem was found using Stokes’ equation. In this paper the solutions are found using the Brinkman model in terms of special functions- Bessel’s function of the first and second kind. In this problem, the drag force experienced by the rotating sphere is also calculated for the less permeability of the porous medium. The model is solved using the asymptotic expansion method for the prescribed boundary conditions. By this method, the model consisting of partial differential equations is reduced into ordinary differential equations – modified Bessel’s equations. The results for fluid velocity, stream function, and separation parameters are found in terms of Bessel’s functions and these results match with the existing literature in the absence of Reynolds number. The graphs are plotted for the drag force on the rotating sphere and separation parameter. It has been observed that the separation of the particles occurs at the surface of the sphere more often for high permeability and the drag was found to be decreasing for low permeability. Both graphs were plotted for a range of Reynolds numbers.
PubDate: 2024-02-17
DOI: 10.1007/s13137-024-00246-z
- The validation of climate in the wine-growing region of the Western Cape
of South Africa-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The Western Cape province, home to the majority of South Africa’s viniculture, is highly vulnerable to the effects of climate change. This study validates the Co-ordinated Regional Climate Downscaling Experiment (CORDEX) temperature and precipitation outputs along with their vinicultural bioclimatic indices over the Western Cape for the historic period (1980–2000) as the first step to determining the ability of the models to accurately simulate future conditions. From the results, we observed that the output had a high agreement with observational data in the case of reproducing monthly average temperatures while precipitation outputs show high variability with moderate to high agreement. The performance of the models in simulating the vinicultural indices greatly depends on location with some models performing better than others. The results of this study will contribute to current efforts to understand the dynamics of climate change and viniculture in the Western Cape, where extreme events associated with climate change are already affecting farmers and potentially impacting the industry’s production and quality.
PubDate: 2023-12-08
DOI: 10.1007/s13137-023-00244-7
- A dispersion analysis of uniformly high order, interior and boundaries,
mimetic finite difference solutions of wave propagation problems-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract A preliminary stability and dispersion study for wave propagation problems is developed for mimetic finite difference discretizations. The discretization framework corresponds to the fourth-order staggered-grid Castillo-Grone operators that offer a sextuple of free parameters. The parameter-dependent mimetic stencils allow problem discretization at domain boundaries and at the neighbor grid cells. For arbitrary parameter sets, these boundary and near-boundary mimetic stencils are lateral, and we here draw first steps on the parametric dependency of the stability and dispersion properties of such discretizations. As a reference, our analyses also present results based on Castillo-Grone parameters leading to mimetic operators of minimum bandwidth that have been previously applied in similar physical problems. The most interior parameter-dependent mimetic stencils exhibit a specific Toeplitz-like structure, which reduces to the standard central finite difference formula for staggered differentiation at grid interior. Thus, our results apply to the whole discretization grid. The study done for the 1-D problem could be applied to the discretization of a free surface boundary condition along an orthogonal gridline to this boundary.
PubDate: 2023-11-23
DOI: 10.1007/s13137-023-00242-9
- Seasonal temperature and precipitation record breakings in Hungary in a
warming world-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Climate change is leading to new daily record-breaking values globally. Since there is a clear shift towards the higher temperature values, the ratio of the numbers of new record high temperatures to record lows indicates the acceleration of global warming differently at regional levels—but is there an amplification for precipitation records as well' The main purpose of this regional analysis is to determine how many record highs/lows are broken on a seasonal level, and how large the area affected is, which enables us to assess the potentially large impacts at a local scale. The analysis is based on the statistical characteristics that the number of record breakings decreases exponentially with time for a stationary climate (when natural variability prevails). The assessment focuses on Hungary and considers the past from 1971 and the future from 2021. Results suggest that (1) currently the ratio of the numbers of new record high to record low temperatures is higher in Hungary than globally, particularly for summer and autumn (around 3.5); (2) substantially more new warm records and almost no cold records are expected by the late century (with a ratio of 140–160) following a high emission scenario, particularly in summer, when the impacts of these record breakings are the largest; (3) new precipitation records in the region are much less affected by the anthropogenic activity.
PubDate: 2023-11-23
DOI: 10.1007/s13137-023-00241-w
- Comparing petrophysical properties and pore network characteristics of
carbonate reservoir rocks using micro X-ray tomography imaging and
microfacies analyses-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Carbonate rocks have complex pore structures as a result of sedimentological and diagenetic processes. We investigated the pore network of four carbonate rock samples originating from an oil well in Hungary. Two samples were from the productive part of the Sarmatian limestone, and the other two were from the dry interval. We employed X-ray computed tomography (micro-XCT) in combination with lab measurements and microfacies analysis. To achieve accurate X-ray image segmentation we investigated and compared several segmentation techniques, including entropy and clustering. We then employed the Naïve Bayes classifier and tenfold cross-validation to assess the accuracy of our results. Our study achieved high accuracy with the type-2 fuzzy entropy technique on various metrics, including precision and recall. The comparison between the measured helium porosity and image-derived porosity showed a close match. Micro-XCT measurements revealed connected pore structure in the productive interval, compared to isolated pores in the dry interval. Microfacies analyses indicated that both the rocks of the productive and dry intervals were deposited in a marine environment, but different diagenetic processes altered the sediment into productive and dry rocks, respectively. The diagenesis of the productive rocks occurred in a meteoric phreatic environment, where secondary pores were created (porosity enhancement). In contrast, the dry rocks underwent meteoric vadose and marine diagenesis, where all previously created pores were filled with cement (porosity destruction). Our study highlights the importance of accurately characterizing the pore network of carbonate rocks, which can aid in understanding reservoir properties and predicting fluid flow behavior.
PubDate: 2023-11-15
DOI: 10.1007/s13137-023-00243-8
- Solute transport prediction in heterogeneous porous media using random
walks and machine learning-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Solute transport processes in heterogeneous porous media have been traditionally studied through the parameterization of macroscale properties using upscaling approaches over a representative elementary volume. As a result, our ability to accurately model solute transport at fine-scale is limited. Combining multiple transport and geometrical observations from the pore scale in a multiphysics framework can enhance the understanding of transport mechanisms that manifest at larger scales. In this paper, we predict conservative solute transport in three sandstone geometries (Castlegate, Bentheimer, and sandpack) that range across different degrees of heterogeneity using a machine learning approach. Our approach, which is based on the random forests (RF) algorithm, performs simulated transport predictions such as solute breakthrough curves. The RF algorithm used in our workflow is a tree-based ensemble method, which builds several different decision tree models independently and then computes a final prediction by combining the outputs of the individual trees. We employ observations, such as solute arrival time and distance traveled, as input to train the predictive model using random walk particle tracking (RWPT) simulations in the sandstones. We employ Bayesian optimization techniques to select the hyperparameter values controlling the structure of the RF model in order to avoid overfitting. Results of our workflow show accurate RF predictions of the RWPT breakthrough curves demonstrating the ability of the RF algorithm to capture the critical flow and transport properties of porous media. We also examine the sensitivity to geometrical sample effects in the training data, which can impact machine learning predictions. The RF algorithm used is able to provide accurate results in real rock samples spanning from unconsolidated granular to consolidated media, highlighting the ability of the model to generalize solute transport problems in porous media.
PubDate: 2023-10-27
DOI: 10.1007/s13137-023-00240-x
- Clemens Heine—Springer’s promoter of geomathematics
-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
PubDate: 2023-10-20
DOI: 10.1007/s13137-023-00239-4
- Antiplane deformation of an orthotropic layer due to surface loads
-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In the present paper, analytical expressions for a two-dimensional deformation of a homogeneous, elastically orthotropic layer of finite thickness overlying a rough-rigid base and smooth-rigid base (SRB) caused by surface loads have been obtained. For a two-dimensional approximation, the governing equations are decoupled into two cases: plane strain and antiplane strain case. We have considered antiplane strain case only. The integral form expressions for the stresses and displacement at any point of the finite layer overlying a rough-rigid or SRB, have been obtained, which have been evaluated analytically using integral transforms tables. The case of shear line loading is discussed elaborately. The displacement and the stresses have been plotted for the two orthotropic materials: Topaz and Barytes and compared with the isotropic case. It is found that there is a significant effect of base as well as anisotropy of material on the variation of displacement and stresses.
PubDate: 2023-09-26
DOI: 10.1007/s13137-023-00238-5
- High order mimetic differences applied to the convection–diffusion
equation: a matrix stability analysis-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The convection–diffusion equation describes physical phenomena where particles or energy are transferred within a physical system due to the processes of diffusion and convection. In this work, we investigate a discretization framework based on the mimetic fourth-order finite-difference staggered-grid Castillo–Grone (CG) operators (Castillo et al. in Appl Numer Math 37(1–2):171–187, 2001. https://doi.org/10.1016/S0168-9274(00)00033-7; Castillo and Grone in SIAM J Matrix Anal Appl 25(1):128–142, 2003. https://doi.org/10.1137/S0895479801398025), which have a sextuple of free parameters. We study the dependency of the stability and precision properties of our numerical scheme based on these CG free parameters, and propose parameters that favor both properties. We compare our results with CG parameters previously mentioned in the literature, including those leading to mimetic operators of minimum bandwidth.
PubDate: 2023-09-13
DOI: 10.1007/s13137-023-00232-x
- Characterization of synthetic porous media images by using fractal and
multifractal analysis-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Fractal and multifractal analysis of porous images allow the description of porous media through a scale-invariant understanding. There have been numerous works that have used these analysis techniques for the description of a great variety of real porous media. However, these studies are usually comparative, being difficult to discern the role played by the pore size and pore distribution in the results of fractal and multifractal analysis. This works develops an in-depth study of different synthetic porous media from a fractal and multifractal approach, in which both the pore size and its distribution in the medium are parameterized. Thus, a set of synthetic binary images have been generated obtaining deterministic and random structures with different fixed pore sizes and also with different rates of pore sizes. Lacunarity is also calculated in order to complete the aforementioned analysis. Results evinces that fractal dimension increases with pore size and that it is higher when the pore distribution obeys a random distribution versus a deterministic one. However, when the pore size is very large, fractal dimension is similar regardless of the pore distribution. From a multifractal approach, pore size is negatively correlated with the degree of multifractality. In fact, in images with mixtures of different pore sizes it is also found that the greater the ratio of small pores, the greater degree of multifractality. By contrast, when the ratio of large pores is relevant, the degree of multifractality also increases due to the merging of macro-pores.
PubDate: 2023-09-13
DOI: 10.1007/s13137-023-00237-6
- A compatible finite element discretisation for the nonhydrostatic vertical
slice equations-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract We present a compatible finite element discretisation for the vertical slice compressible Euler equations, at next-to-lowest order (i.e., the pressure space is bilinear discontinuous functions). The equations are numerically integrated in time using a fully implicit timestepping scheme which is solved using monolithic GMRES preconditioned by a linesmoother. The linesmoother only involves local operations and is thus suitable for domain decomposition in parallel. It allows for arbitrarily large timesteps but with iteration counts scaling linearly with Courant number in the limit of large Courant number. This solver approach is implemented using Firedrake, and the additive Schwarz preconditioner framework of PETSc. We demonstrate the robustness of the scheme using a standard set of testcases that may be compared with other approaches.
PubDate: 2023-09-03
DOI: 10.1007/s13137-023-00236-7
- A reduced basis ensemble Kalman method
-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In the process of reproducing the state dynamics of parameter dependent distributed systems, data from physical measurements can be incorporated into the mathematical model to reduce the parameter uncertainty and, consequently, improve the state prediction. Such a data assimilation process must deal with the data and model misfit arising from experimental noise as well as model inaccuracies and uncertainties. In this work, we focus on the ensemble Kalman method (EnKM), a particle-based iterative regularization method designed for a posteriori analysis of time series. The method is gradient free and, like the ensemble Kalman filter (EnKF), relies on a sample of parameters or particle ensemble to identify the state that better reproduces the physical observations, while preserving the physics of the system as described by the best knowledge model. We consider systems described by parameterized parabolic partial differential equations and employ model order reduction techniques to generate surrogate models of different accuracy with uncertain parameters. Their use in combination with the EnKM involves the introduction of the model bias which constitutes a new source of systematic error. To mitigate its impact, an algorithm adjustment is proposed accounting for a prior estimation of the bias in the data. The resulting RB-EnKM is tested in different conditions, including different ensemble sizes and increasing levels of experimental noise. The results are compared to those obtained with the standard EnKF and with the unadjusted algorithm.
PubDate: 2023-09-01
DOI: 10.1007/s13137-023-00235-8
- Statistical analysis of heat-induced rock physics and mineralogical
alteration processes of monzogranite samples from Bátaapáti, Hungary-
Free pre-print version: Loading...
Rate this result:
What is this?
Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Heat-induced physical changes of rocks, as would happen in fire accidents, have crucial importance in the long-term stability of underground openings such as tunnels or radioactive waste disposal chambers. The thermal behaviour of monzogranite from the Radioactive waste repository of Bátaapáti (Hungary) was studied in that context. Room temperature (22 °C) and a series of high temperature (250 °C, 375 °C, 500 °C, 625 °C, 750 °C) heat-treated samples were tested. P and S- ultrasound pulse velocity, bulk density, Duroskop rebound, uniaxial compressive strength, and modulus of elasticity were measured and compared, detecting temperature-related changes. Descriptive statistics and non-parametric Kruskal–Wallis and Median tests were carried out to analyze the heat-induced rock mechanical and mineralogical alteration processes. Based on these results using the data set of physical parameters, it is possible to predict the heating temperature of granitic rocks when the firing or heat stress conditions are unknown. Additionally, the data could be utilized for design and monitoring systems in underground repositories or tunnel systems constructed in granitic rock settings globally. The study demonstrated that significant alteration occurs above 500 °C; all studied rock-mechanical parameters decreased rapidly. These changes are linked to the thermal expansion, micro-cracking in micro-fabric, and volumetric increase and fragmentation of quartz inversion. Consequently, the propagation velocities of P- and S-waves also decreased significantly. Bulk density and Duroskop surface strength significantly decreased above 375 °C, while uniaxial compressive strength and modulus of elasticity dropped drastically at 750 °C after a linear decrease.
PubDate: 2023-08-23
DOI: 10.1007/s13137-023-00234-9
|
Hybrid journal (It can contain Open Access articles)
