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 suggests the method for forecast of surface deformation during excavation operations in restraint urban conditions using the slurry trench technique based on FEM simulation. The results of numerical simulation of the construction of a semi-underground structure with slurry trench technique are given. The regularities of the change in the stress-strain state are determined depending on the trench parameters and the physical-mechanical properties of the soils. The work presents the troughs of surface subsidence during the construction of an excavation using the slurry trench technique, the diagrams of bending moments, transverse and longitudinal forces arising in the trench. Numerical experiments in Plaxis 2D and 3D were performed to estimate the discrepancy between modeling results in a plane and volumetric formulation of the problem.
In work the option of the multipurpose underground complex being part of the multystoried high-rise building is considered. The complex settles down in underground part of the building and carries out a base role, replacing with itself the usual plates-but-pile base. Predesigns by a method of final elements taking into account staging of construction of an underground complex and the land high-rise building are executed. Sizes and a picture of distribution of vertical displacements are received as a result of calculations.
In work results of modeling of work of two options of the multipurpose underground complex being the base of the multystoried high-rise building are considered. The complex plays a role of the combined foundation. Modeling is executed taking into account stage-by-stage construction of underground and land part of the building.
Geomechanical analysis of surface subsidence development due to construction of deep underground station is presented. The station is a typical pylon structure, which is usually used during construction of the latest subway station in Saint Petersburg. Numerical modeling of step-by-step underground station construction is conducted. The results of the numerical analysis allow to predict the magnitude of surface settlement and understand the wide of settlement trough.
Structural spatial concept of subway transferring node for two, three andfour metro lines, which are located in unified underground facility issuggested. Preliminary structural fem design of underground facility isdone. Different construction methods are considered and step by step excavation isincluded in finite element modeling.
Finite element analysis of soil – pile interaction for two different design schemes is done. 3d analysis and stage construction is considered. As the results of FEA modeling vertical displacement of soil and subsidence trough for different stage of construction are drawn and analyzed.
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.
Numerical modeling of cast iron lining stress and strain state of pylon deep underground station is done. Due to complex geometry of underground station, step by step excavation and lining installation numerical modeling was done in three dimensional space.
The paper presents results of numerical modeling by application of plastic constitutive models with various failure criteria. The Balmer’s and Balandin’s failure criteria have been elaborated in FISH language and they have been applied to simulate two basic problems which are: compression of rock sample and construction of excavation in rock mass.
Forecast of stress and strain state of deep underground metro stations is considered in this article. A complex approach to study of static work of the metro stations including the in situ testing at different stages of their construction and numerical modeling with finite element method is shown.
Geomechanical forecast of stress-strain state of deep underground subway station is considered. Static work of structures of subway station based on complex approach is shown, including in situ testing and numerical modelling (finite elements method) during different stages of construction.
The intense-deformed condition of one of station complexes of the Saint Petersburg underground testing mutual influence from a trading-entertaining complex located over it is considered.
Numerical modeling by finite element method of stress-strain state of lining of subway tunnels in the zone of their mutual influence has been carried out. The tunnels are not parallel to each other, have different depths and were driven at different times. Two experimental sites were selected for modeling, corresponding to the sites where field observations were made. The use of the finite element method allowed to solve the problem in a volumetric setting and to take into account the complex configuration of the tubes, the layering of the massif and the stages of tunnel construction.
The paper shows the nature of formation of the vertical load on the column-type lining of the "Komendantsky Prospekt" station of the St. Petersburg subway deep-laid with regard to the technology of its construction. On the basis of numerous field studies, mathematical modeling by the finite element method (FEM) was carried out. The three-dimensional elastic and viscoelastic models at various stages of the station construction were used for the calculations. The calculations resulted in the construction of epures of vertical load distribution on the deep-filled metro station column lining. The character and regularities of its formation without and taking into account the influence of the middle tunnel face were revealed.
The construction technology of subway stations significantly affects the development of the stress-strain state (SSS) of the lining-soil system. This work is aimed at revealing the nature of this influence and changes in the stress-strain state of the station column-crest complexes in the geological conditions of the St. Petersburg Metro. In-situ studies were carried out at the "Komendantsky Prospekt" station, which is under construction, during 7 months. Measurements were made with string sensors of linear deformations and a portable digital period meter. The regularities were revealed and the influence of technological processes (development of the upper vault, core, reverse vault and disassembly of temporary filling tubing) on the formation of the stress-strain state of the column-race complexes was evaluated.
The task of full-scale studies was to observe the processes of expansion in the ends of reinforced concrete beams and the formation of the stress-strain state of reinforced concrete and steel columns. The measurements were carried out with the help of string sensors of linear deformation (PLDS-400) and a portable digital periodometer (PCP-1). Long field observations (14 years) of the development of the stress-strain state of the column-carrier complex were carried out at the deep-filled column-type station. As a result of analyzing the obtained data, we concluded that the applied method of uncompressing the transoms with Freycinet jacks does not lead to the transition of their girder double-concrete operation into a single-jointed arch one. The regularities were revealed and the effect of technological processes (development of the upper vault, core and reverse vault) on the formation of the stress-strain state of the column-carrier complex was evaluated. The last measurement made at the end of 2001 showed that the process of stress and strain development over time continues to this day.
Field observations show that the distribution of stresses around mine workings is uneven both in transverse and longitudinal directions. To take into account this distribution of stresses, we consider the interaction of the mine support with the surrounding rock massif. The roof support is considered as an elastic long closed cylindrical shell. The load acting on the shoring changes irregularly both along the shell and in the transverse direction: p = p(x,0), where x is the distance along the generatrix expressed in fractions of the radius; 9 is the central angle expressed in radians. Then, two cases can be considered: the support is under the action of axisymmetric radial load depending only on one variable x, the support is subjected to load depending only on the angle 9 The solution of the problem for the load of the form P = p(x, 9) is obtained by summing up these two solutions. Let's estimate average loads on a roof support for typical conditions of shaft construction in the elastic mode of interaction: R 0 = 3.0; R l = 3.5 m; R - 3.25 m; h - 0.5 m; Vj = 0.25; / = 0; v - 0.25; = 2 - 10 4 MPa; £ = 2 - 10 4 MPa Thus, when modeling vertical shaft support by a closed cylindrical shell the calculated average load is three times less than the corresponding value for a flat problem.