The goal of this study is to enhance the method for predicting geomechanical processes during mine working construction in an elastoplastic rock mass with dilatancy. We present the results of experimental research into the volumetric strength of rocks and the specifics of volumetric strain development under plastic shear. We demonstrate rock dilatancy and provide diagrams showing how volumetric plastic shear strains change at different levels of accumulated shear strains. We process the rock testing results using A.N.Stavrogin’s plasticity condition. We propose a new analytical solution for predicting the stress-strain state of the rock mass in areas with inelastic strains, based on A.N.Stavrogin’s plasticity condition. This includes equations for modelling the limit state zone of rock around a mine working. We introduce an algorithm for predicting the stress-strain state of the rock mass. We investigate how the size of the limit state zone around a mine working relates to rock dilatancy parameters, lateral stress coefficient, and working depth. We examine how contour displacements develop for a circular mine working under plane strain conditions, considering various plasticity parameters and rock dilatancy indicators. We implement A.N.Stavrogin’s plasticity condition in the Abaqus software package. Our research results help define the scope of the analytical solution. The solution remains physically meaningful only when the limit state zone forms around the entire perimeter of the mine working. The proposed numerical approach removes this limitation. It applies to any geomechanical state of the rock mass and to mine workings with any cross-sectional shape.
The article is devoted to the analysis of approaches to modeling the stress-strain state of a block rock mass in the vicinity of a single mine workings and in the area of rock cantilever influence during the development of the Khibiny apatite-nepheline deposits. The analysis of the existing in international engineering practice ideas about tectonic disturbances as a geomechanical element and the experience of predicting the stress-strain state of a block rock mass was carried out. On the basis of the analysis, the formulation of the basic modeling tasks is carried out and its main results are presented. Methodological recommendations for solving similar problems were developed.
The development of prediction method of earth surface settlement during the tunneling in heavy geological conditions of megalopolises was the purpose of the article. The experimental-analytical and numerical prediction methods of earth surface settlement during tunneling by mechanized tunnel boring machines are proposed and justified. The volume balance of earth surface settlement and volume of additionally excavated soil during tunneling are accepted as initial condition for experimental-analytical prediction method. The comparison of predicted and experimental data of earth surface settlement in different countries is performed. The prediction with numerical methods is produced in 3D with application of elastic-plastic soil body model. The matching of numerical calculations data and data of experiments and analytical calculation is revealed. The proposed prediction methods may be used for geotechnical substantiation of projects of tunneling in heavy geological conditions.
The three dimensional stress distribution in tunnel set with allowance for relative influence and building sequence is investigated. To complete the task the finite elements analysis was used. The values of stress concentration factor and conformities of stress distribution in the «lining – mass» system are estimated. The relative influence of each tunnel in tunnel set with allowance for building sequence is identified.
Numerical model of lining yield element is created. Induced deformation Force – Displacement behavior of lining yiled elements with different geometrical sections is founded. Deformation state of lining element under induced displacement is presented.
In the learned article the substantiation of the mutual influenced tunnel’s temporary support elements stress-strain state prediction technics is adduced. The problem is sold in three-dimensional arrangement with allowance for building technology. The analysis of numerical simulation results is adduced. On account of this analysis the main ways of solution for such problem class is spotted.
The intelligent technology of designing of the constructions of pillar underground station is adduced. Station is building with applying of low-settle technology, which takes into consideration main stages of the building process. The scheme of interaction of the system «support lining-soil massif» was accepted as basic scheme of calculations. The calculations of the stress-strain condition of constructions was performed with applying of finite-elements method.
In this learned article the analysis of reinforcing effect, which appears during the process of the drilling of tunnels with using of contledge of the face which applied in tunnel boring machines, is adduced.By applying of the finite-elements method the family of graphical relations, which reflects the processes of the development of displacements, is approached. For the reason of analysis of these relations the optimal value of contledge of the face if maximum permissible displacements of the earth surface are known have been suggested.The influence of the main strength characteristics of Couloumb – Mohrs’s theory of strength on stability of the face of the tunnel and the necessary value of contledge of the tunnel’s face are defined.
The article presents the rationale of temporary supports used in the drilling of new mines, which provides for the construction of model projects of reconstruction of old tunnels. Finite-element method analyzed the changes of stress-strain state containing tunnel complex array during the drilling of new mines. Based on the analysis, a number of findings to explore the possibility of reducing the thickness of the permanent support of new mines in tunnel complex - the new tunnel, and transport and drainage culvert.
In the article the analysis of consolidating effect from application of the anchor fastening, which using at driving of transport tunnels in the conditions of North Caucasus is produced. The change of the stress-strain condition of the rock massive, which is weaked by the mining of the circular outline is certain with the finite-elements method. On the basis of the executed design the row of graphic dependences, which describes changing of the sizes of limitary areas depending on strength and deformational properties of the rocks. Due to results of the conducted work the direction of further researches is seted.