Other outputs
On the occasion the International Symposium ISRM EUROCK 2017, the monograph Rockbursts in Ostrava Karvina Coalfield was published by Institute of Geonics AS CR, supported by the grant AS CR AV21 – Natural risk. Monograph deals with the phenomenon of rockburst which has accompanied the coal mining in the Czech part of the Upper Silesian Coal Basin. Next to short overview of the history, the work also focuses on a detailed description of the geological and geomechanical properties of the rock mass, describes the main and typical features of rockbursts and attention is focused on the principles and methods of forecasting and preventing the rockburst. A separate chapter is devoted to familiarizing the reader with some typical examples of rockbursts including the commentary concerning the prevention measures applied. The publication is available in the Institute of Geonics AS CR in Ostrava.
Software enables to determine and visualize the full stress tensor according to properties of rocks and deformation measurement on strain gauges in the conical probe installed in rock mass. The password is requested to open the archive file.
The code is appropriate for voxel based problems, for example for problems of micromechanics arising from CT scans. The code follows the algorithm of the preconditioned conjugate gradient method and its parallelization is based on Schwarz methods and on a decomposition of the original domain into overlapping subdomains. The communication of parallel processes is realized by message passing given by the MPI standard. License ( TXT, 35 kB ).
It is considered a quasistatic elastic-perfectly plastic model contaning the Mohr-Coulomb yield criterion, a nonassociative plastic flow rule and a nonlinear isotropic hardening. The loading process is controlled indirectly through the settlement of the slope top and the gravity load factor is an unknown variable. The problem is discretized by the implicit Euler method in time. For discretization in space, two type of finite elements can be used: linear simplicial elements or 8-noded quadrilateral elements with 3x3 integration quadrature. The code contains an improved return-mapping and consistent tangent schemes. Further, the semismooth Newton method is used for solving nonlinear systems of equations. For more details, we refer to S. Sysala, M. Cermak: Subdifferential-based implicit return-mapping operators in Mohr-Coulomb plasticity. License ( TXT, 35 kB ).
It is considered a quasistatic elastic-perfectly plastic model contaning the Mohr-Coulomb yield criterion and a nonassociative plastic flow rule. The problem is discretized by the implicit Euler method in time. For discretization in space, two type of finite elements can be used: quadrilateral Q1 elements with 2x2x2 integration quadrature or quadrilateral Q2 elements with 3x3x3 integration quadrature. The code contains an improved return-mapping and consistent tangent schemes. Further, the semismooth Newton method is used for solving nonlinear systems of equations. For more details, we refer to S. Sysala, M. Cermak: Subdifferential-based implicit return-mapping operators in Mohr-Coulomb plasticity. License ( TXT, 35 kB ).
It is considered a quasistatic elastoplastic model contaning the Mohr-Coulomb yield criterion, a nonassociative plastic flow rule and a nonlinear isotropic hardening. The problem is discretized by the implicit Euler method in time. For discretization in space, two type of finite elements can be used: linear simplicial elements or 8-noded quadrilateral elements with 3x3 integration quadrature. The code contains an improved return-mapping and consistent tangent schemes. Further, the semismooth Newton method is used for solving nonlinear systems of equations. For more details, we refer to S. Sysala, M. Cermak: Subdifferential-based implicit return-mapping operators in Mohr-Coulomb plasticity. License ( TXT, 35 kB ).
The proposed methodology is based on the currently used methods for the analysis of convergence on one profile of the tunnel. These procedures allow us to gain some initial stress tensor components which are projections of the stress tensor in a plane perpendicular to the tunnel axis. The proposed methodology assumes measurements on the two profiles, which lie on two parallel planes perpendicular to the axis of the tunnel. Such configuration allows us to get the whole initial stress tensor. We work with objects whose size is comparable to the tunnel dimension, so the present methodology increases the reliability of the initial stress estimation. Certificate ( PDF, 1000 kB ).
It determines to experts of mining companies with rockburst risk, to experts of companies judge rockburst design measures and to experts of the mining authority for procedure of effectiveness evaluation of destress blasting operations carried out in rockburst prevention.
It is considered an elastic-perfectly plastic part of the Jirasek-Grassl model. The problem is discretized by the implicit Euler method in time. For discretization in space, two type of finite elements can be used: linear simplicial elements or 8-point quadrilateral elements with 9-point numerical quadrature. The semismooth Newton method is used for solving nonlinear systems of equations. License ( TXT, 35 kB ).
It is considered a quasistatic elastic-perfectly plastic model contaning the Drucker-Prager yield criterion and the associative plastic flow rule. The problem is discretized by the implicit Euler method in time. For discretization in space, two type of finite elements can be used: linear simplicial elements or 8-point quadrilateral elements with 9-point numerical quadrature. The semismooth Newton method is used for solving nonlinear systems of equations. License ( TXT, 35 kB ).
It is considered a quasistatic elastoplastic model contaning the Drucker-Prager yield criterion, a nonassociative plastic flow rule and a nonlinear isotropic hardening. The problem is discretized by the implicit Euler method in time. For discretization in space, two type of finite elements can be used: linear simplicial elements or 8-point quadrilateral elements with 9-point numerical quadrature. The code contains an improved return-mapping scheme developped for nonsmooth plastic potentials. Further, the semismooth Newton method is used for solving nonlinear systems of equations. License ( TXT, 35 kB ).
It is based on the FEM and the corresponding linear system of algebraic equations is solved by the preconditioned conjugate gradient method with the additive two level overlapping Schwarz preconditioner. The stiffness matrix for the coarse problem is created by a new aggregation technique. Both Dirichlet and Neumann boundary conditions can be applied. In the second case, arising singular system can be efficiently solved making use of projections. Software package contains two codes. The program AGGREG serves for preparation of an aggregated matrix. The code SOLVER_AG is designed for the parallel solution of large linear systems and is parallelized with the aid of OpenMP. More details ( PDF, 79 kB ), license ( TXT, 35 kB ).
Such systems are subsequently used for testing iterative solvers and preconditioners. The code is characterized by: simplicity and possibility of easy modifications, directly solving model problems on square domains (generalization possible), controlled random coefficient oscillations (stochastic generation of heterogeneity), fast system assembling using vectorization and sparse reconstruction, possible testing of Krylov type solvers with both (block) matrix and matrix free (variable) preconditioners. More details ( PDF, 310 kB ), license ( TXT, 35 kB ).
Carbon dioxide and rock massif. At these days the sequestration of CO2 into deep aquifers (collectors) still remains very actual. The selection of suitable localities for CO2 sequestration is very difficult and exacting problem. Direct experiences of miners from mines, where the miners come into deep natural collectors of carbon dioxide give good information for selection and methodology for surveying of other localities. Therefore the institute published this monograph about the occurrences of CO2 in rock massif in mines in the area of the Bohemian massif. This monograph sums up and documents the natural conditions of occurrences of this gas in mines in rocks or in the coal seams, which are created by means of natural processes.
This model was set up using seismic tomography, and its subsequent visualization and animation starts with the transformation of the measured 3D data. The derived velocity model was applied during the procedure of relocalizing micro-earthquake foci. Submitted to Studia Geophysica et Geodaetica.