scholarly journals Protective Measures during Construction of Ground Structures over Existing Underground Structures

2020 ◽  
Vol 19 (5) ◽  
pp. 377-383
Author(s):  
A. A. Dalidovskaya ◽  
V. G. Pastushkov
Keyword(s):  
Strain State ◽  
Negative Impact ◽  
Surface Structures ◽  
Underground Structures ◽  
Safe Operation ◽  
Stress Strain ◽  
Protective Measures ◽  
Stress Strain State ◽  
New Construction ◽  
The Impact

Today, there is an acute issue of ensuring the safe operation of buildings and structures located in the immediate vicinity of new construction. The process of performing works on the installation of load-bearing structures and their further operation can have a negative impact on already existing facilities. In this regard, the task of developing innovative methods and tools to ensure the safe operation of such structures as subway running tunnels is very urgent. To solve it, a reliable forecast of additional deformation and appointment of a complex of protective measures are required.  In addition, much attention should be paid to the numerical modeling of the system “surface structures – protective measures – underground structures”. As an example of assessing the impact of new construction, namely, the erection of surface structures over existing underground  ones, one  can  cite  the  construction  of  a transport  interchange  at  the  intersection  of  Nezavisimosty  Avenue with Filimonov Street. As protective measures, a protective screen on bored piles has been used here, which made it possible to minimize significantly dynamic and static effects on the lining of tunnels and other underground structures of the subway. Effectiveness of protection application is confirmed by the result of monitoring the stress-strain state of running tunnel structures at all stages of traffic  intersection construction. Protective measures and continuous monitoring of the stress-strain state in structures help to avoid accidents during construction and further operation. 

scholarly journals Stress-strain state of retaining walls depend-ing on them construction

2020 ◽  
pp. 76-82
Author(s):  
Vitalii Ruchkivskyi
Keyword(s):  
Strain State ◽  
Negative Impact ◽  
Retaining Wall ◽  
Rational Solution ◽  
Existing Buildings ◽  
Underground Structures ◽  
Stress Strain ◽  
Stress Strain State ◽  
New Construction ◽  
Protective Structures

In modern urban planning, in most cases, the construction of buildings and underground structures has a negative impact of new construction on existing buildings. As a rule, the foundations of new buildings are designed with a greater depth of laying compared to existing buildings. As a result of excavation work and subsequent installation of load-bearing structures of underground structures, existing buildings are subjected to uneven subsidence. Cracks may appear in the walls and the serviceability of structural elements may be impaired. Before the geotechnics there is a task to determine the dimensions of the zone of influence of new construction, ie the area where negative processes of stress-strain formation can occur. To comply with the safe operation of existing buildings, there is a need for a reliable forecast of additional deformations of existing buildings and structures, as well as the choice of a rational solution for the protection of the pit. Modeling of the stress-strain state of the retaining wall of the pit with different diameters and changes in the number of rows of piles. Calculations of the stress-strain state of the protective structures together with the soil base were performed using the finite element method for a horizontal load of 1 m.p. retaining wall (the problem of flat deformation). 4 variants of the problem were solved: V1 - retaining wall with piles 13.5 m, 420 mm in diameter, arranged in one row; V2 - retaining wall with piles 13.5 m, 620 mm in diameter, arranged in one row; V3 - retaining wall with piles 13.5 m, 420 mm in diameter, arranged in two rows; V4 - retaining wall with piles 13.5 m, 620 mm in diameter, arranged in two rows; The influence of increasing the diameter of piles in the structure of the retaining wall on the increase of the moment of inertia of the section, which leads to the perception of a greater value of bending moments, is shown. The technical and economic comparison of the pit fencing options is performed. The most rational solution of excavation of the pit in these conditions is revealed.

Modeling of the stress-state longwall face during coal mining with the technology of roof management complete drop and stowing

2020 ◽  
pp. 99-106
Author(s):  
I. E. Mazina ◽  
A. A. Stel’makhov ◽  
L. F. Mullagalieva
Keyword(s):  
Coal Mining ◽  
Strain State ◽  
Underground Mining ◽  
Negative Impact ◽  
Hydrological Regime ◽  
Coal Bed ◽  
Stress Strain ◽  
Environmental Friendliness ◽  
Modeling And Analysis ◽  
Stress Strain State

Underground mining of coal deposits has a negative impact on all components of the environment. When developing a coal deposit, it is coal mining technology that determines the scale and consequences of the negative impact. Changes in the stress-strain state of the geo-environment can lead to a violation of the hydrological regime, increased gas emission from the host rocks, the initiation of gas-dynamic processes. Choice of roofing management technology - as a geotechnological method of natural and technical system management determines the environmental friendliness of coal mining and creates safety conditions. The article deals with the technology of roofing control during coal production. For this purpose mathematical modeling and analysis of stress-strain state of the bottomhole part of the coal bed for the conditions of S.M. Kirov is performed. As a result of modeling, two technologies of roof control were analyzed - complete caving and stowing. For the worked out clearing leaves filled with either caving rocks or stowing material, there are characteristic unloading zones in the massif to be worked and overworked, as well as pressure reference zones, which fall on the parts of the pillars associated with the lava. It was found out that the application of the stowing technology creates conditions for minimization of gravitational stresses in the geoenvironment, as well as significantly reduces the potential energy of form change.

scholarly journals CONTROL OF ACTIONS OF STEEL TANK IN WORKING

2018 ◽  
Vol 22 (4) ◽  
pp. 66-74 ◽  
Author(s):  
A. A. Vasilkin
Keyword(s):  
Strain State ◽  
Low Cycle Fatigue ◽  
Operating Conditions ◽  
Maximum Effect ◽  
Safe Operation ◽  
Stress Strain ◽  
Load Bearing ◽  
Stress Strain State ◽  
Steel Tank ◽  
Steel Tanks

In steel tanks made by the method of rolling, defects of a geometric shape often occur in the area of the welded welded joint of the wall. Subsequently, in these areas, as a result of low cycle fatigue, an unacceptable defect appears in the form of a crack, which makes it necessary to remove the reservoir from operation and carry out a set of measures for its repair. To determine the terms of safe operation of vertical steel tanks with geometric defects, it is proposed to use the methodology control of the actions of structures of load-bearing structures, one of the directions of which is the regulation of the stress-strain state of steel structures. To implement the possibility of regulating construction, it is necessary to identify such parameters, the change of which will give the maximum effect in achieving the set goals. As the indicated parameters, the design characteristics (material properties, design scheme, geometric characteristics) and factors of external influences (load, operating conditions) can act. To regulate the stress-strain state design of vertical steel tanks, the following regulators are proposed: product loading height, wall deflection arrow and permissible number of tank loading cycles. By numerical calculation of the VAT of the vertical steel tank design with geometric defects, the necessary values and values of the stress state are determined. Further, using known analytical dependencies from the field of fracture mechanics, it is possible to determine the permissible number of loading cycles of the reservoir before the appearance of a crack-like defect. The application of the methodology control of the actions of structures load-bearing structures, by means of a certain change in the established control parameters, allows increasing the number of loading cycles of the reservoir, thereby increasing the period of safe operation of the defective reservoir and thereby increasing the economic efficiency of the tank farm.

scholarly journals Choice of technologies of ensuring exploitation suitability of buildings in the underground construction area

Vestnik MGSU ◽  
2020 ◽  
pp. 452-461
Author(s):  
Emil Imran Оglu Alirzaev ◽  
Marina E. Dement'eva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain State ◽  
The Finite Element Method ◽  
Underground Construction ◽  
Underground Structures ◽  
Stress Strain ◽  
Computer Complex ◽  
Stress Strain State ◽  
Element Method

Introduction. One of the serious problems in the construction of underground structures in a dense urban area is the occurrence of excess deformations of the foundations of operating buildings that fall into the zone of influence of underground construction. The subject of the study was the calculated justification of the modern technology of compensatory injection. The relevance of the task is determined by the fact that the choice of the most effective protection technology should be based not only on a comparison of technological precipitation with maximum permissible values, but also on the assessment of the possibility of monitoring and controlling the movements of the foundations of buildings and structures during construction and subsequent operation. The purpose of the study was to compare various methods of protecting the foundations of existing buildings and structures and justify the selection of the most effective of them for further implementation and dissemination in the design and construction of urban underground structures. Materials and methods. On the basis of the survey data of the operated building falling into the impact zone of excavation of the pit for the construction of the installation and shield chamber of the subway, the parameters of the stress-strain state of its foundations are studied by mathematical modeling. The problem was solved by the finite element method based on the software and computer complex Z_Soil v.18.24. Results. Based on the analysis of the results of the examination of the administrative building using the finite element method, a change in the parameters of the stress-strain state of the foundations was modeled with various technologies for strengthening it. In the course of solving the geotechnical problem, it was found that the minimum impact on the foundations of the building during the construction of the pit was obtained in the method of compensatory injection. The system of criteria for making a decision on choosing an effective way to ensure the suitability of buildings in the underground construction zone for operation is substantiated. Conclusions. The results of this work can be used to justify the choice of technology for prevention and control of excess deformations of foundations. The function for calculating the volume of injected material in the Z_Soil software and computer complex can be used to justify the consumption of materials and the economic efficiency of the technological solution.

Simulating the stress–strain state of a thin plate after a thermal shock

2021 ◽  
Author(s):  
A. V. Sedelnikov ◽  
S. V. Glushkov ◽  
V. V. Serdakova ◽  
M. A. Evtushenko ◽  
E. S. Khnyryova
Keyword(s):  
Temperature Field ◽  
Thermal Shock ◽  
Thin Plate ◽  
Strain State ◽  
Stress Strain ◽  
Homogeneous Plate ◽  
Stress Strain State ◽  
The Impact ◽  
Elastic Elements

The paper is devoted to simulating the impact of a thermal shock on a thin homogeneous plate in the ANSYS package. The assessment of the stress–strain state is carried out and the dynamics of changes in the temperature field of the plate is determined. The obtained results were compared with the data of other authors and can be used when taking into account the thermal shock of large elastic elements of spacecraft.

scholarly journals Influence of the sequence of erection of build-ings on the formation of the stress-strain state of the system «base-foundation-overhead structures»

2020 ◽  
pp. 32-44
Author(s):  
Liudmyla Skochko ◽  
Artem Shabaltun
Keyword(s):  
Strain State ◽  
Design Parameters ◽  
Soil Base ◽  
Stress Strain ◽  
High Rise ◽  
Stress Strain State ◽  
Subsequent Section ◽  
The Impact ◽  
Ground Structures ◽  
Formulation Of Problems

The influence of the order of construction of houses on the formation of the stress-strain state of the system "foundation-foundation-above-ground structures" is investigated For this purpose, several options for setting tasks for the phased construction of multi-section building sections are considered. With this in mind, it should be noted that the construction of each subsequent section has an impact on the built entirely or partially adjacent section. That is why this effect should be investigated to predict how serious this impact may be, and to draw appropriate constructive decisions. Thus, the main objectives of the study are: Creation of SEM without taking into account the stages of construction of the house; Calculation of a house with a phased loading of 5 floors. Taking into account changes in the order of construction of sections; Formation of SEM taking into account the sequence of erection of sections without including the sequence of erection of floors within the boundaries of the current section; Research of the impact of the calculation of sections of a multi-section building without and taking into account the summary of subsequent sections. The research of the impact of the sequence of construction and installation of the object will allow us to assess the stress-strain scheme at all stages of construction, so changes in the behavior of the scheme will be recorded at all stages of construction specified by the designers. To do this, the change in the stress-strain state (VAT) of the system "foundation - foundations - above-ground structures" must be modeled with different options for stages of construction, taking into account the real parameters of the soil base and so on. The interaction of piles in different zones of sections, the work of grids in the foundations of high-rise buildings are considered. The research was carried out with the help of numerical modeling of the system "foundation - foundations - aboveground constructions". The redistribution of forces in the piles depending on the formulation of problems on the stages of construction of sections and design parameters (location of piles in characteristic zones, the influence of the stiffness of the aboveground part on the redistribution of forces). Characteristic zones in the foundation are distinguished: they are central, lateral, angular and especially at the joints of adjacent sections. The redistribution of efforts between piles and a grid is revealed.  

scholarly journals Laws of gas draining in the massif disturbed by mining operations

2019 ◽  
Vol 109 ◽  
pp. 00047
Author(s):  
Serhii Kurnosov ◽  
Volodymyr Zerkal
Keyword(s):  
Strain State ◽  
Abutment Pressure ◽  
Gas Permeability ◽  
Experimental Studies ◽  
Rock Massif ◽  
Gas Release ◽  
Mining Operations ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Impact

A method for calculating gas permeability of the rock massif depending on its stress-strain state is presented. By using methods of the mine experimental studies, influence of mining operations in the adjacent long walls on intensity of gas release from the previously worked-out long-pillar was determined, as well as impact of the massif stress-strain state on efficiency of the drainage boreholes. Formulas were obtained for calculating coefficients of the impact of zones with static and dynamic abutment pressure on intensity of gas draining in the previously worked-out long-pillar.

Investigation of the Influence of Geometric and Technological Factors on the Stress-Strain State of Metal in the Implementation of the Combined Rolling-Pressing Process

2014 ◽  
Vol 936 ◽  
pp. 1918-1924 ◽  
Author(s):  
Sergey Lezhnev ◽  
Eugeny Panin
Keyword(s):  
Metal Forming ◽  
Strain State ◽  
New Technology ◽  
Grain Structure ◽  
Stress Strain ◽  
Technological Factors ◽  
Stress Strain State ◽  
Fine Grain ◽  
The Impact

In the development of new technology metal forming the main purpose is improvement the quality of the source material. The main aspect of quality improvement is increasing the strength characteristics. Often to increase the strength of deformable metal should be given reduced grain structure, up to subultra and even nanolevel. There are several ways to obtain sub-ultra-fine-grain structure of metals, and one of those ways is a method of severe plastic deformation (SPD), implemented in the whole volume of the deformable metal.In this work computer modeling was performed of the combined process "rolling-pressing" with the use of grooved rolls and equal channel step matrix with varying basic geometric and technological factors which have a significant impact on the process, what was made for the analysis of the impact of various factors on the stress-strain state of the process.

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