## Vol 8, No 3 (2017)

Evaluation of Master’s program development “Innovative technologies of low-rise construction”
Ponomarev A.B., Sychkina E.N.

#### Abstract

The article aims at analyzing the results of the first stage of the master’s program development called “Innovative technologies of low-rise construction”. In Russian it is considered to be a market trend to focus on the low-rise housing, as it has a number of advantages compared to the multistorey housing. Low-rise housing makes it possible to reduce costs, time, use energy-efficient technologies and act autonomously. A lack of highly qualified personnel is a constraint against a widespread application of innovative technologies in our country. The article pays much attention to the disciplines creating unique master’s professional competencies. During the master's program students gain skills related to technical risk and geotechnical assessment when it comes to low-rise housing construction. They learn how to design energy-efficient foundations and energy-efficient constructions; use advanced building materials and innovative construction techniques. The article could be of interest to a wide range of geotechnical engineers and builders who want to extend their areas of expertise and acquire new professional knowledge and skills. It is also interesting for graduates looking for a vocational retraining or those who plan to use the knowledge and skills for themselves. The “Innovative technologies of low-rise building” master’s program was developed based on the standards used for the “Construction” major and requirements of potential employers to the program graduates. The article presents the clearly defined goals and objectives of the developed program that are consistent with the mission of Perm National Research Polytechnic University and with the demands of the potential target customers.
Construction and Geotechnics. 2017;8(3):5-12
DETERMINATION OF BEARING CAPACITY OF PILES IN THE GROUP
Gotman N.Z., Alekhin V.S., Sergeev F.V.

#### Abstract

This article considers the problem of making computations of groups of piles (pile fields) accounting for the interaction between piles in the soil environment, which causes additional stress in the soil in the inter-pillar space and creates the effect of piles "compression" with soil from loads transferred to the neighboring piles. The difference between a single-pile and a group-pile operation is shown. The article focuses on estimating the ultimate resistance of the pile depending on the pile field parameters. The aim of this study is to develop a method which makes it possible to find the ultimate resistance of a pile base in groups of piles based on calculations and tests of a single pile, but taking into account the interaction between the piles in the soil. This issue is relevant as there are no special methods enabling the estimation of piles bearing capacity in a pile field, which results in material-intensive and expensive solutions in designing foundations. The article presents the method which determines additional stresses in the soil in the inter-pillar spaces when groups of piles are loaded. The additional stresses cause an increase of the base ultimate resistance in comparison with a single pile. The comparison of the proposed analytical solution with the numerical solution of axisymmetric task in Plaxis 2D is performed, the results of which are quite similar. The authors have proposed a method of computing the allowable loads of piles in pile groups which is based on the calculations and tests of single piles taking into account the interaction between the piles in the soil
Construction and Geotechnics. 2017;8(3):13-21
INTEGRATED TECHNOLOGY OF GEOTECHNICAL SURVEY
Boldyrev G.G., Barvashov V.A., Idrisov I.K., Khrianina O.V.

#### Abstract

The paper describes an integrated computer-based technology optimizing site survey operations (e.g. number of test holes) and office work (geological activities). This objective is achieved by analyzing structure settlements and tilts online at each current stage of the survey operations. To this end, the test data (e.g. qc and fsprofiles) is uploaded online after each survey stage into a computer that processes the data and calculates the potential structures’ settlement and respective tilts at this stage. Then the obtained data is downloaded back to the server, and the geological survey team decides to go on or to stop the survey, depending on the difference between the data of the current and the previous stage. The subsoil ratio distribution under future structure is calculated at each stage and sent to a Design Engineer at the last stage for future design work. The method does not require any office work or geological data processing, because no geological report is required, and all the above operations are carried out on site along with the survey. The Designer receives three values, such as one settlement and two tilts. Such sequence of operations is possible thanks to a new method for subgrade ratio distribution analysis and application which has been developed in GEOTEK. The respective software and hardware were patented. Static, dynamic penetration and drilling sounding techniques are proposed to test soil properties in situ. Soil data is processed with the help of known correlation equations to obtain physical and mechanical soil parameters. The number of test holes is determined by the designed subsoil-structure sensitivity to the test data already available by online settlement and tilts analysis during the tests in situ. The associated hardware and software for soil testing in situ and data processing are described. Test data collection and processing is performed with ASIS software together with an additional software code for the test data interpretation. The data is uploaded online to the computer on site or elsewhere to calculate subsoil parameters, followed by structure settlements and tilts analysis online. If necessary, the test data can be uploaded to a remote server of the surveyor. The settlements at the test points that are caused by the mean structure pressure on the subsoil are computed for pressure. Firstly, they are computed at the test points, and then the subgrade ratios are computed at these points which are interpolated to the whole foundation surface according to Shepard’s formulae, while the computation variants are considered for different values in Shepard’s approximation formulae.
Construction and Geotechnics. 2017;8(3):22-33
APPLICATION OF SHELL STRUCTURES MADE OF COMPOSITE NANOMATERIALS
Kasharina T.P., Kasharin D.V.

#### Abstract

The development of infrastructure and environmental safety of the natural systems of the Far North requires new techno-natural buildings and structures which can be created using composite nanomaterials. These materials have to embrace an enhanced resistance to temperature, subsidence and ice conditions. At the same time, it is necessary to justify new technical solutions for hydraulic structures including their bases, water-retaining structures, engineering protection, etc. It is also important to develop technical recommendations based on theoretical, experimental, field studies, ecological, environmental and social performance indicators of new technical solutions of elements or structures as a whole. The article provides substantiations for individual structural elements, i.e. primer columns, reinforcing tapes; it also describes necessary conditions for composite nanomaterials that are taken into account in different climatic conditions and ensure the restoration of damaged areas and the life-cycle time of an entire structure. It is proposed to take into account the heteromodularity of the composite nanomaterials (properties of hydrophobicity, tribology, reagance). The proposed new technical solutions will allow to improve the infrastructure of urban areas by increasing their quality, in particular, transport, hydropower and water supply systems. It is recommended to use membrane, soil filling, soil reinforcing, soil strengthening structures and their combinations as water retaining, regulating, flood controlling, bank protecting and antimud slide protection structures. A widespread introduction of such structures requires additional experimental, theoretical and field studies of properties of new nanomaterials.
Construction and Geotechnics. 2017;8(3):34-40
TECHNOLOGICAL SETTLEMENTS DURING THE CONSTRUCTION OF A DIAPHRAGM WALL
Shuliatev O.A., Minakov D.K.

#### Abstract

The article is devoted to the problem related to determining the technological settlements of foundations in nearby buildings during the construction of a diaphragm wall. It is based on the materials of the scientific research work which has been carried out in 2015 as the governmental assignment (customer FAU "FTSS"). It includes the available data analysis gained from monitoring the technological settlements, the analysis of existing methods aimed at estimating technological settlements and results of numerical modeling of the diaphragm wall construction. As a result, a large number of both foreign and national sources have been analyzed which revealed the following facts. Firstly, technological settlements vary in a wide range from 1 to 63 mm. Secondly, the quantitative evaluation of the technological settlements during the construction of the diaphragm wall is performed by using the finite element method; and the ratio between the settlements gained from the monitoring data and the settlements gained from estimations varies from 48 to 175%. The main modeling stages in constructing the diaphragm wall are the trench excavation and concreting. Two main approaches to modeling the trench excavation stage have been identified, i.e. modeling of the excavation by changing the soil properties within the trench or by the load equivalent to the hydrostatic pressure of the bentonite slurry. As a rule, when modeling the concreting stage, a bilinear dependence proposed by Lings is used. A model dimensionality is an important issue for the numerical calculation of technological settlements. In most studied works, a three-dimensional model was used in the calculations, which allowed considering the size of the panel length. Calculations related to the 2-dimensional model lead to overestimated values of soil displacements. To verify the method determining the technological settlements, the numerical modeling in PLAXIS 3D was carried out using the data from the construction site of a multi-storey building in Greater Cairo. As a result of this simulation, a good compliance of the calculated technological settlement with the monitoring data was obtained (the settlement according to the monitoring data is 7 mm, the settlement according to the calculations is 6 mm). Based on the example of the construction site in Greater Cairo, it was assessed how various factors (the distance between the diaphragm wall trench and the foundation of the building, the panel length, the load under the foot of the foundation and the density of the bentonite slurry) influence technological settlements. This assessment has shown that it is important to take the investigated factors into account when estimating the technological settlements.
Construction and Geotechnics. 2017;8(3):41-50
ENGINEERING METHOD OF CALCULATING SOIL PRESSURE ON RETAINING WALLS
Shapiro D.M.

#### Abstract

Currently the method of calculating the horizontal active soil pressure according to the limit balance theory (Coulomb’s wedge theory) in the assumption of the flat sliding plane is widely used in engineering design. In case of irregular loading distribution and non-horizontal embankment surfaces, the use of the Coulomb’s method leads to the results that can’t ensure the limit soil stress state behind the back facets of the retaining walls. The article describes the engineering method of calculating the active soil pressure on vertical retaining walls which is based on Moor-Coulomb equation considering internal friction and cohesion of soil. The horizontal active pressure is obtained as a primary tension depending on the vertical pressure behind the back facets of the retaining wall. It is assumed that the vertical pressure distribution depends on the shape of the computational domain and acting loads; and it does not change when the soil shifts from the pre-limited to the limited state. Thus, in order to determine the vertical pressures, it becomes possible to use the solutions of the theory of elasticity, FEM and empirically verified approximated techniques, which examples of are given in the article. On the contact facet the vertical pressures of the one-sided force system are doubled and the tangent pressures are equal to zero in accordance with the “method of images” which consists in substituting the embankment behind the retaining wall by the symmetrical computational domain. The suggested calculation method is not related to using reference data which are suitable for a limited number of problems with non-horizontal forms of embankment surfaces. The obtained solutions (which remain approximated) are based on strict equations of soil mechanics theory.
Construction and Geotechnics. 2017;8(3):51-61
NEW TECHNOLOGY OF CONSTRUCTING BUILDINGS ON POTENTIALLY DANGEROUS LANDSLIDE SLOPES
Vlasov A.N., Korolev M.V., Chuniuk D.I., Korolev P.M.

#### Abstract

This article considers the issues of producing buildings and constructions on potentially dangerous landslide slopes. It shows the advantages of the foundation setting in such conditions using piles which are set into the ground by a static load. The technologies which are used to insert piles during new construction operations and during the reconstruction of buildings are also described in this article. A new efficient technology is proposed for production of combined piled foundations which allows reducing construction time and costs. The idea of the technology is that due to a certain sequence of operations related to the construction of foundations and upper structures of the building, the load from an incompletely constructed building is firstly perceived by the slab foundation, and then, as the building is constructed, the increasing load is transferred to the piles set through the holes in the plate. On the one hand, this makes it possible to fully utilize the bearing capacity of both the foundation slab and the pile of the combined foundation, and, on the other hand, to reduce the number of piles and, to some extent, control the structure settlement when it is being constructed. In addition, the description and the results of laboratory and field experiments are given using the testing model of studying the piled foundations which has been developed according to the proposed technology. This technology can be used both to build structures on potentially dangerous landslide slopes, as well as in ordinary conditions of mass industrial and civil constructions. Nowadays all the main elements of the proposed technology have been worked out. In particular, a method determining the bearing capacity of piles when they are inserted using the creeping relaxation regime, the technology of piling into leading wells, and the technology of increasing the bearing capacity of immersed piles.
Construction and Geotechnics. 2017;8(3):62-70
MULTILAYERED SYSTEM OF SAND BEDS WITH CLOSED REINFORCEMENT FOR LOW-RISE FOUNDATIONS
Bai V.F., Luzin A.I.

#### Abstract

The paper offers a new type of foundations for low-rise constructions in soft clay water-saturated soils. It is a multilayered system of sand beds with a closed reinforcement. This system combines the advantages of geosynthetic reinforcement and use of low deformable sand beds in soft soils. It is suggested to use the closed reinforcement in the system of sand beds, as it will exclude the soil extrusion between the reinforcement layers and increase the bearing capacity due to constraint conditions of soils. The authors suggest an ideal reinforcement design scheme by Jones within the sector of stretching strains (an area in the soil with emerging stretching forces when a reinforcement element is placed in it); describe the setting advantages and disadvantages of reinforcement and low deformable sand beds in soft soils. The paper presents the experimental results proving that the curvilinear form of the sand bed supporting base provides a more even distribution of stresses in the basement, which either excludes or decreases plastic zones of the bedding. Thus, the curvilinear supporting surface of the sand bed increases the range of the bedding linear work, as the soils located along the whole curvilinear surface start to act. In conclusion the authors present the process which make up the multilayered system of curvilinear sand beds with closed reinforcement.
Construction and Geotechnics. 2017;8(3):71-77
STUDY OF INTERACTION BETWEEN BARRETTES AND SOIL BASE CONSIDERING THEIR SIZES AND SHAPES
Sidorov V.V., Stepanishchev K.I.

#### Abstract

In case of an intensifying production of high-rise buildings, geotechnical engineers often face design problems related to high loaded soil bases with a load up to 1 MPa. This is the reason of a widespread use of deep foundations made of various shape piles including barrettes. Barrettes have become commonly used in many countries, as they are able to bear large vertical and horizontal loads. However, unlike the traditional piles, the studies of barrettes operational characteristics are far behind practice. This is mainly due to a high cost and complexity of full-scale experiments regarding this type of foundation. Therefore, in present investigations the researchers focus on studying the bearing capacity, settlement and mobilization of the shear forces on side surfaces that are obtained via sensors installed on the experimental barrettes. However, there are interesting and understudied questions about the interaction of barrettes with the soil at a distance from the side surfaces (the interaction problem), choosing an optimal shape (aspect ratio), placement pitch in two directions, and stress concentration in the corner areas. These problems can and must be solved by numerical methods to obtain high-quality results that can subsequently lead to real cost-cutting results. Finite element computer applications like PLAXIS 3D allow to successfully solve the aforementioned problems and make algorithms in order to produce optimal design solutions. The article presents the course and results of numerous finite element calculations to study the interaction of a single and group barrette with its soil base. It became possible to determine the interaction zones of a single barrette along short and long sides, which allowed gaining a more efficient location of them in terms of the composition of the foundation. The results are shown by solving the test problems similar to real projects.
Construction and Geotechnics. 2017;8(3):78-88
THE USE OF FLY ASH AS FOUNDATION BASES
Mashchenko A.V., Ponomarev A.B., Spirova T.A.

#### Abstract

Environmental issues are gaining more and more attention from public and environmental organizations. Nowadays there has been a great discussion in finding the forms and methods of energy production for the future. At the moment there is a huge amount of industrial waste in Russia which contributes to environmental pollution and occupies large areas. It is possible to single out a certain group of production wastes which create typical environmental problems in each region of Russia. Recycling of large-scale waste requires a developed network of enterprises that will implement modern technologies and produce necessary products from wastes. The building materials industry is such a promising industry where large-scale waste is used. Scientific and technological progresses in the building production are not possible without the use of new materials in structures that comply with such parameters as lightweight, technological effectiveness, low thermal conductivity and high chemical resistance. The article presents the laboratory tests of fly ash. The strength, deformation and heaving properties of ash are determined. The results are compared with the previously obtained results of laboratory investigations of soft plastic clay soils. There is also an attempt to improve the mechanical characteristics of fly ash by reinforcement with geosynthetic materials. Basalt chopped fiber was chosen as a reinforcement. The article presents the test methods, results and analysis of studies. The test results are given in tables and the conclusions are given too.
Construction and Geotechnics. 2017;8(3):89-96
FULL-SCALE TESTING OF REINFORCED FOUNDATION PADS
Tatiannikov D.A., Ponomarev A.B.

#### Abstract

This article considers stamping tests of full-scale models of reinforced foundation pads in real engineering and geological conditions of the city of Perm. These tests entail the final experimental stage in studying the bearing capacity of reinforced foundation pads. Numerical modeling was performed at the first experimental stage, the results of which were used to formulate the basic operation parameters of the reinforced foundation pads. Before the full-scale tests, model stamping tests of various types of reinforced foundation pads had been made and formulated on the basis of the numerical modeling results. The results of the model stamping tests made it possible to clarify the qualitative parameters of the work, to reveal the rational design of the reinforced foundation pads. In order to check the results of numerical modeling and model stamping tests, as well as to find the real bearing capacity of the reinforced foundation pads, full-scale stamping tests of specially prepared reinforced foundation pads were carried out. The main purpose of the experimental work is to obtain real parameters for the operation of reinforced foundation pads. To achieve this goal, certain objectives were identified, such as: - identify the regularity of settlement for the reinforced foundation pads under load by constructing the experimental plots of the "settlement-pressure" dependence; - estimate the bearing capacity at a maximum settlement of 12 cm; - study the stress-strain state of the base of the improved reinforced foundation pad under load by measuring stresses and deformations using soil pressure cells and marks. The solution of these problems will development a technique of calculating the bearing capacity of reinforced foundation pads.
Construction and Geotechnics. 2017;8(3):97-105
ANALYSIS OF PREDICTIVE MODELS FOR SHEAR STRENGTH OF FIBER REINFORCED SOIL
Grishina A.S., Ponomarev A.B.

#### Abstract

Today soil reinforcement is one of the most popular methods of increasing the bearing capacity and reducing the deformability of soil bases and earth structures. To effectively use reinforcing geosynthetic materials in construction operations, "discrete" approaches have been developed to design soil reinforced structures. Such approaches suggest calculations according to independent characteristics of soil and fibers which results in avoiding long and expensive testing of soil reinforced composites. Generally accepted methods of calculating soil reinforced structures were developed only for the reinforcement with planar geosynthetic materials. Soil reinforcement using short randomly distributed fibers requires an additional evaluation. The issue of designing fiber reinforced soil structures with a subsequent standardization of design approaches is still open in geotechnical practice. The developed "composite" approaches to determine the shear strength of a fiber-soil require shear strength testing of fiber reinforced soil specimens as input parameters, which significantly increases the design cost. To verify the experimental data obtained by the authors, the "discrete" model of the fiber reinforced soil proposed by Zornberg was chosen. The expressions obtained by Zornberg make it possible to evaluate the shear strength of the fiber-soil according to the characteristics of the unreinforced soil and fibers. As a result of comparing the experimental data and the data obtained from the results of the substitution into the model, the conclusions were drawn about a good convergence of the model in the component of the specific cohesion for the specimens reinforced with fibers of up to 0.5% by the weight of dry soil. To reinforce more than 0.5 %, the difference in the experimental and predicted data is significant. So, it is necessary to introduce the field of applicability and improve the model considered for the subsequent introduction of the concept of fiber-soil into geotechnical practice.
Construction and Geotechnics. 2017;8(3):106-112
APPLICATION OF EXPRESS METHODS FOR DETERMINATION OF CHARACTERISTICS OF FILL SOILS
Sazonova S.A., Rumiantsev S.D.

#### Abstract

The main controlled parameter in the production of bases is the compaction ratio; however, deformation characteristics are important for the prognosis of bases settlement. The aim of the research is to determine the relation between the monitored parameters at the construction site and the characteristics used in the design of the foundations, which will allow a quick and effective control of the quality, as well as a prediction of the settlement of fill soils. There are various methods aimed at an express control of the density of fill soils. One of them is the impact stamping method with the help of a dynamic densitometer. The problem of investigating the applicability of this method in industrial and civil construction is relevant. This paper presents the results of experimental studies aimed at assessing the applicability of the DPG-1.2 to control the deformation characteristics of fill soils. The research was carried out in the laboratory conditions of Construction Production and Geotechnics Department of Perm National Research Polytechnic University. The compaction ratio and soil moisture were accepted as the controlled parameters. As the measured parameters, we accepted the compression modulus of deformation, the dynamic modulus of elasticity, force and settlement. The subject of investigation is uniform coarse sand with a maximum density of 1.74 kg/m3 and an optimum moisture content of 14 %. 18 series of tests were carried out with different coefficients of compaction at a constant humidity. Based on the results of the experimental studies, the dependencies were obtained, i.e. the dependence of the compression modulus of deformation, the dynamic modulus of elasticity, and the plastic precipitation on the coefficient of compaction; dependence of the impact force on the plastic settlement. Also, additional experiments were carried out to determine the depth of the compressible strata from the impact load. The obtained dependences were analyzed from the point of the effect of the compaction ratio on the deformation characteristics, as well as the determination of the applicability limits of the dynamic densitometer during the layerwise control of the fill soil compaction.
Construction and Geotechnics. 2017;8(3):113-120