Construction and Geotechnics

The definition of a “public space” with the availability as its main feature is given in this article. The data on the progress in promoting physical education and mass sports in the city of Perm and the condition of public sports facilities is provided. The reconstruction solutions for “Molot” stadium including the pre-design concept are suggested. The characteristics of “Molot” sports center (universal sports palace) have been made according to the General Plan of the city of Perm. The present condition of this territory is described with its advantages and disadvantages. The data has been gained by using the results of observations and surveying, thus proving that it is necessary to reconstruct this area. The definition of “sports parks” and their examples found in Russia are provided. The concept of developing the territory of “Molot” stadium with the aim to create a sports park is proposed according to the main principles of urban design. We think that it is reasonable to introduce a new concept for the stadium reconstruction. It is advisory to stick to the idea of the sports center and make it a public center available for a lot of city events. Multifunctionality is an important feature of modern public areas which makes this area attractive for a wide range of people. The zoning plan of the area with a short description of each zone is given in the paper. General problems connected to the reconstruction and management of public facilities are described.

The basic principles (categories) of the new soil mechanics and geotechnical engineering are determined, set out in a hierarchical order and classified. Fundamental differences between new and previous developments are specified in the paper, such as a new classification of the soil state (overconsolidated - normally consolidated - underconsolidated), geotechnical model (geomassiv - basement - foundation - building), soil weight (assessment of γ h in situ), pore pressure (element of formation and evolution of lithosphere), analogue-discrete soil model (brittle body with an infinite elastic modulus), Young's modulus (elasticity modulus), capillary soil model (beaded capillaries and capillaries of Zhomen), the effect of Kulachkin - Radkevich (pore pressure may be lower than atmospheric), load-bearing capacity (Gersevanov and acoustics in the soil), acoustics in geotechnics (continuity, integrity, strength and geometry of piles and other reinforced concrete structures). The analytical and experimental data in various regions of Russia and abroad has been given in the paper. The assessment of state and prospects of geotechnics and soil mechanics are described.

An increasing production of concrete and concrete reinforced items requires a considerable increase in production of fillers with different physical and chemical properties. It especially concerns the production of lightweight concrete, for which it is necessary to use fillers with a lower density compared to that of the expanded clay gravel. An alternative filler for lightweight concretes is a granulated foam glass, which combines high thermal insulation properties, incombustibility, rigidity, environmental safety and almost unlimited service life. Foam glass is a highly porous inorganic insulation material consisting of closed cells of spherical and hexagonal shapes; it is characterized with a high mechanical strength and frost resistance with a relatively low average density. Foam glass belongs to the class of cellular glasses. Raw materials for production of the granulated foamed glass are quite diverse. Usually it is produced based on the cullet which is mixed with a blowing agent and various additives. The resulted mix is granulated and further heated in the foaming furnace with a subsequent cooling. Due to the production of foam glass, one of the urgent environmental problems is partially solved which is the secondary use of a large number of domestic and industrial cullets accumulated on landfills. The initial stage of producing granulated foam glasses is the choice of raw materials which determine the properties of the final product. For this purpose, it is necessary to analyze raw materials and determine the impact of various components of the initial charge on the quality of the granulated foam glass. The article considers main raw material products which are widely used in the production technology of foam glass and specifies peculiarities of their application. Also, the article cоnsiders the mechanism of alkaline and silicate reactions in the case when the granulated foam glass is used as a filler in lightweight concretes. Additives which reduce the rate of these reactions are proposed.

The Russian Federation is the coldest country, most of its territory is covered with permafrost. The rest of the territory has the areas of seasonal freezing and thawing of soils. Seasonal freezing is one of the main factors determining the structure, depth of the underground constructions and the type of transport constructions. In addition, the seasonal freezing soils containing clay particles or being in the water-saturated state under freezing are exposed to frost heaving, which is able to cause significant deformation and destruction of objects. Studying the freezing and thawing processes includes the study of thermophysics of soils. Thermal properties of soils are of a great practical importance in the field of design, construction and use of motor roads, underground heating networks, foundations of buildings, in particular shallow foundations for the low-rise buildings and structures, as well as power foundations and heat exchanger systems. Thermophysical properties of soils are characterized by the coefficient of thermal conductivity, specific or volumetric heat capacity and temperature diffusivity. The article compares different ways of calculating thermal properties of soils, such as computations and experimental methods, as well as the method based on regulatory documents. The cmparison results prove that it is necessary to study the soil thermophysics using direct laboratory methods, since the real values of thermophysical characteristics may significantly differ from the calculated and experimental data. The accuracy of determining the thermal properties of seasonal freezing and thawing of soils are relevant for shallow foundations of buildings and structures, but they are insufficiently studied and require further studies using advanced software systems.

A pedestrian crossing is an essential element of the transport system in any city. The major function of a pedestrian crossing is to ensure the safety of pedestrians. Underground pedestrian crossings are much safer compared to regular pedestrian crossings, but they are much more expensive. The construction costs can be decreased due to the use of flexible corrugated metal structures instead of ordinary concrete structures. For a rational design of pedestrian structures, it is necessary to know their stress-strain states. The stress-strain state of flexible corrugated metal shells largely depends on the strength and deformation characteristics of the surrounding soil. Therefore, improving the characteristics of the backfilling soil is an urgent task in reducing the costs of constructing pedestrian tunnels. One way to improve the strength and deformation characteristics of soils is to use reinforcement. Currently there is a large number of reinforcement schemes and reinforcing materials. One of the most prospective ways of soil reinforcement is the use of fiber filaments. Fiber reinforced soils have significantly higher strength and deformation characteristics in comparison with unreinforced soils. Numerical modeling of the tunnel shell made of the corrugated metal structure was carried out to evaluate the effectiveness of using fiber reinforced sand. Ordinary sand and sand reinforced with polypropylene fibers have been used as soil backfill. The calculation results of the pedestrian tunnel structure in different strength and deformation characteristics of the backfill soil are presented in this article. The analysis of the stress-strain state of the metal corrugated construction of the underground pedestrian crossing indicated that the maximum deformation of the backfill from sand reinforced with cement is 70 % less; as for the filling from the sand reinforced with polypropylene fibers, it is 29 % less than for the non-reinforced sand. Normal stresses in the metal corrugated shell when using the backfill from the reinforced concrete sand are 86 % less; as for the the sand reinforced with polypropylene fibers, it is 42 % less compared to an ordinary sand.

The possibilities of using for construction the slopes of Khvalynian accumulation terrace which have been formed as a result of both natural and natural-anthropogenic landslides. Until recently, the construction of houses in landslide area was over-Presto. But in recent years, landslides and landslide-prone areas are increasingly being developed with various types of construction when a certain complex shore protection works. The problem of development of territories composed of NABU-hayuschih soils, prone to swelling and formation of landslides in the present time is very important. The underestimation of the swell and landslides were the reason Noah deformation of many industrial and civil constructions. The building expertise of the slope stability is achieved by dumping the design profile and dog-Canoga of contranct of sand in the bottom of the slope. For calculation of stability Nena-loaded slope, and selected two sites. We have theoretically calculated the stability factors of the slopes. On the top of the stairs it is 2.13 for house 1, it is 1.45 for house 2 and it is 1.53 for house 3. For the lower platform along two lines the minimum value is 1.21. The recommendations on building foundations in this area are given.

In Russia much attention today is paid to the use of new technologies that would significantly improve the quality of construction, the speed of payback, and thus minimize the timing of work production. Modular construction combines various technologies prefabricated buildings, and in Russia there is sufficient experience and achievements in the development of volume-block construction. Particular attention to this technology is associated with the need to achieve global goals in our country: to solve the problems of providing the population of Russia with affordable and comfortable housing in the framework of state programs; for rapid construction and restoration of housing destroyed in the event of natural disasters, or the creation of fully functioning temporary mobile buildings and structures; for simplification by unification and standardization of installation works during the reconstruction of buildings and structures, in the construction of special-hazardous and industrial facilities; for transfer to factory conditions, excluding the influence of weather conditions, specialized processes for assembling equipment with heat, water, gas services, welding and wet processes; and as a result, the simplification of design due to the creation of typical series of objects and the introduction by manufacturers of databases and product catalogs - unified modules (or modular units). The article considers and analyzes the experience of the use of modular construction in Russia and abroad, it formulates main values and disadvantages of using this technology. Summarizing the analysis, conclusions and ways of solving and optimizing of the technology of block-modular construction in Russia are determined in terms of normative technical standardization, construction planning, the most rational application.