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.
When constructing buildings and structures for industrial and civil purposes, it is important to ensure safe working conditions for the tower crane operator and contractors of construction and installation works on the construction site, since these conditions largely determine the performance of the tower crane and the pace of construction in general. Accidents associated with the use of lifting equipment in construction often lead not only to injuries and death within the construction industry, but also affect passers-by who find themselves in the danger zone due to the non- compliance of the construction organization project with the requirements of existing codes of rules containing requirements for labor protection and industrial safety in construction. The article analyzes the causes of accidents in construction that result from the operation of tower cranes, as well as ways to ensure their reliable and safeoperation. The theoretical substantiation and engineering and technical solutions of safety during construction and installation works during the construction of objects due to the improvement of the design of the tower crane cabin and its equipment are offered. The results of theoretical and experimental studies of sensorimotor activity of the operator of the construction machine, which are the basis for engineering solutions developed at the level of inventions of tower cranes cabins of increased visibility and their equipment, are presented.
The article deals with issues of necessity of training and development of working staff for construction industry of Russian Federation for creation of competitive construction industry, meeting the high quality and efficiency standards, working in basis of modern financial and economic, technical and management mechanisms. One of the ways to solve this task of innovative development is modernization of architectural and building design, in particular implementation of BIM technology enabling making efficient decisions at all stages of building and structures life cycle – from investment concept till operation and even demolition. In relation to this the industry demands highly qualified workers and engineers (bachelor students) being able not only to get new knowledge but to use them for solving practical tasks of modern construction industry and market. The article present a concept of designing educational programme for training students with major 08.03.01 «Construction» (bachelor degree) focusing on systematized knowledge, skills and tools for training, in particular, through interconnection and continuity during course and diploma papers based on BIM technology.
The article examines a method of forecasting strength properties and their scale effect in fissured rock mass using computational modelling with final elements method in ABAQUS software. It shows advantages of this approach for solving tasks of determining mechanical properties of fissured rock mass, main stages of creating computational geomechanic model of rock mass and conducting a numerical experiment. The article presents connections between deformation during loading of numerical model, inclination angle of main fracture system from uniaxial and biaxial compression strength value, size of the sample of fissured rock mass and biaxial compression strength value under conditions of apatite-nepheline rock deposit at Plateau Rasvumchorr OAO «Apatit» in Kirovsky region of Murmanskaya oblast. We have conducted computational modelling of rock mass blocks testing in discontinuities based on real experiment using non-linear shear strength criterion of Barton – Bandis and compared results of computational experiments with data from field studies and laboratory tests. The calculation results have a high-quality match to laboratory results when testing fissured rock mass samples.
Simulation-based finite element method of forming the features of the stress-strain state in pillar at the ore body downstream horizontal layers with a mined-out space. The obtained regularities of redistribution of stresses in pillar and surrounding rock massif are allowed to substantiate an effective way to reduce the bump hazard in mining operations.
The main features of the entries supports in theinfluence zone of open pit and second working are established. Research was carried out using a numerical modelling by finiteelements method.
In this article the analysis of the stress-strain state of the external and internal contours of the lining, 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. The finite element method diagrams obtained the minimum and maximum principal stresses on the outer and inner contours of output. Relationship obtained in the surface sediments depending on the depth of the tunnels.
Numerical modeling of deep excavation construction is done in plane strain condition. The influence of boundary condition, contact condition between soil and structures, constrain of cantilever wall, thickness of the wall and anchors on the strain condition of the soil is found.
Method of excavation support and tunnel lining design is worked out. Stiffness of soil strata is considered as nonlinear elastic. The problem is solved in plane strain condition according to elastic theory. The distribution of average load on excavation support is given.
Nondestructive optical methods for measuring of the «thick» films thickness of the order of 0,001-1,00 mm are analyzed. It is shown that using the laser beam radiation and modern optical and electronic schemes possible to decrease the time of single measurement to 1ms and less at the measuring frequency of 10-50 hz. The possibility of measuring thickness and spreading coefficient and evaporation kinetics of liquid films is demonstrated. A new computer method of the data processing aimed to determine the film thickness from the angle dependence of the laser beam reflection coefficient by the film is offered. The offered procedure and the experimental technique realizing it permits to decrease the thickness determination uncertainty to the order of ten.
The parameters of the stress state of nearbord massif of deep open pit on the example of the field development of the V.Grib. This research was done by numerical simulation using finite elements method.
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.
The parameters of underopencast rock mass stress-strain condition for Koashva deposit are defined. The estimation of influence of surface development with opencast on the stress-strain distribution in the mass is revealed. Research is revealed with appliance of finite-elements method.
The comparative analysis of the stress-strain state in the circuit and in the vicinity of a single generation of circular and arched curves of elastic and non-linear strain diagram types of rocks. Graphic dependences were obtained by the finite element method, reflecting the nature of the stress-strain state. The actual values of the tangential stress concentration factor on the circuit were obtained using non-linear functions.
Method of normal load prediction on vertical shaft lining which is constructed in nonlinear rock mass is suggested. It is supposed, that limit state zone is formed around excavation. The deformation properties of rock mass in the suggested method are determined according to nonlinear rock model. In order to predict stress and strain state around excavation the equations of deformation plasticity theory are used. The Mohr-Coulomb strength criteria is taken as a yield surface.
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 aim of the article is to develop a method of forecasting the state of stress of the ore mass around excavations for ores of weak and medium strength. The paper presents experimental studies on the deformation of ore samples of low and medium strength in the forging equipment in conditions of volume stress state. A physically nonlinear model is used to describe the deformation process of ore mass. The study of the stress state of physically nonlinear ore mass around excavations of round and valuated cross-sections is performed. Values of coefficients of tangential stress concentrations on excavation contour are found for different types of ore. Solutions to physically nonlinear problems in preparatory excavations in the development of the Yakovlevskiy deposit of rich iron ore using a slicing method are considered. Methods for forecasting the stress state in rock mass around mine excavations can be used to assess their stability in the mining of ore of low and medium strength at the Yakovlevskiy iron ore deposit and in the rock and soil masses.
This article deals with the issues concerning the accidents relevant to the underground pipelines operation. These pipelines transport gas, oil and its derivatives. The statistical analysis results of accidents in underground pipelines operated in Russia, as well as the analysis of the explosion causes in underground pipelines and primarily gasified objects are provided. It is shown that stress corrosion arising as a result of the phenomenon of hydrogenation is the most dangerous for large-diameter gas pipelines. The author proposes the justified and protected by RF patents new engineering solutions for consideration. They are aimed at improving resistance of steel structures against corrosion. Also a method of increasing the hardness, strength and wear resistance of steel parts surfaces by rapid cementation due to saturation of the carbon steel surfaces; a steel alloying method using aluminum to obtain diffusion coatings; and a method of applying a corrosion resistant and stable to acids and alkalis coating on the steel surface are presented. Proposed new technologies are accompanied by an explanation of the physical and chemical processes occurring in steel. The experimental results confirmed the validity of those decisions.