CC BY
17
SRSTI 67.21.17
Zhukenova Gyulnara Abaevna
PhD, associate professor, Department of «Industrial, Civil and Transport Construction», S. Toraighyrov Pavlodar State University, Pavlodar, 140008, Republic of Kazakhstan, e-mail: [email protected].
Kenzhebek Nurdaulet Kenzhebekuly
undergraduate student, S. Toraighyrov Pavlodar State University, Pavlodar, 140008, Republic of Kazakhstan, e-mail: [email protected].
Baymagambetov Rustem Kazymbekovich
undergraduate student, S. Toraighyrov Pavlodar State University, Pavlodar, 140008, Republic of Kazakhstan, e-mail: [email protected].
Bayzhanov Daniyar Sanatkanovich
undergraduate student, S. Toraighyrov Pavlodar State University, Pavlodar, 140008, Republic of Kazakhstan, e-mail: [email protected].
TWO-DIMENSIONAL MODELING OF THE INTERACTION OF FOUNDATION MODELS WITH A SOIL BASE
Currently, numerical modeling is an important and rapidly developing method of studying the deformation processes in soils. The rapid growth of computing possibilities contributes to the development of this direction of research. Improved existing and developed new calculation algorithms and approaches to solving problems. Some ofthe approaches developed decades ago, have experienced a weakening of interest and reducing the scope of and now again are widely used. This is due to new computing possibilities, new approaches and statements of problems and class extension ofthe investigated phenomena.
Main objective of studying of physical process is creation of models by means of which it can be described. The successful solution of such task means an opportunity to explain the occurring phenomena, and also to predict development of process at change of any factor. Depending on the required accuracy in model a certain complex ofthe phenomena which need to be taken into account is considered.
Keywords: numerical modeling, foundation, finite element method, deformation of a soil base, loading conditions.
INTRODUCTION
The first and main task of a research is the correct formulation of a task. Formulation of a problem assumes detailed definition of an object of a research. For this purpose it is necessary to define accurately the phenomena and processes which it is supposed to investigate and define the corresponding properties of the environment by means of which they can be described. Besides it is necessary to define geometry of an object and its structure, conditions in which it is and also conditions of loading and duration of the studied process. From that how successful the formulation of a task is, success of her decision depends.
The next step is the choice of a model and determining its parameters. The more complex the model, the more parameters that need to know, i.e. to determine experimentally. The behavior model of the environment is based on the generalization and interpretation of experimental data.
Numerical modeling based on the finite element method, allows to accurately and quickly producing of analytical calculations and forecasting of various geotechnical problems. To study working models of the foundations, it was decided to examine and compare the work of each type of foundation under the influence of horizontal and stepped deformations.
MAIN PART
Modeling the influence of horizontal and stepped deformations on the work of model of single pile was performed on the conditions of plane problem of two-dimensional model. The dimensions of the geometric model were adopted from the condition that the distribution of horizontal and stepped deformations will be negligible outside of the predetermined zone.
Fig. 1 shows the general geometric model of single pile in soil basis for numerical modeling and set it horizontal and stepped deformations.
Figure 1 - General geometrical model of single pile on the soil base
For setting of the standard boundary conditions create in the basis of the model the partial fixation and in the right vertical boundary - sliding fixing. Fixing (Fig. 2) in a certain direction will be presented in two parallel lines perpendicular to this direction. Thus, the sliding movable support will look like two vertical parallel lines and the solid fixing - by hatching.
For choice of boundary conditions there are two types: prescribed displacements and loads. In every direction all boundaries must have one boundary condition. In other words, if a certain free boundary is not set to the appropriate boundary condition, respectively, are applied to natural conditions (prescribed load and the free displacement is equal to zero).
it
it
Figure 2 - Fixing of a geometrical model of single pile on soil base
Some of the points of a geometric model must have prescribed displacements, it is necessary that to avoid a situation when the displacement is unknown. The simplest example of a given displacement is a fixation (zero displacement), but can also be set and non-zero displacement.
In this case, the boundary conditions of the walls of the model were given in the form of a hinged movable support with free movement along the +x axis in coordinate limits on у axis.
In the Plaxis program complex this type of boundary conditions is set automatically, because it is suitable for most geotechnical problems.
For modeling the soil behavior for a given geometric model should be accepted corresponding model of soil and its parameters. In Plaxis soil characteristics were collected in data on materials, which are stored in the appropriate database. The dataset from the database can be assigned to one or more clusters.
By dataset on materials select Soil & Interfaces (Soil and Contact Surface).
Datasets on materials are created, generally, after input of boundary conditions. Before creation of a mesh shall be set data sets on all materials, and all clusters and constructions shall have the dataset corresponding to them.
A specified soil of base received parameters of physic-mechanical properties of soil (Table 1, Fig. 3) given by results of laboratory researches.
Table 1 - Characteristics of model of soil base
Parameters Desig-nation Value Unit of measurement
Model of soil Mo del Mohr - Coulomb —
Type of behavior of soil Type Drained
Specific gravity of soil У unsat 17.0 KN/m3
Specific gravity of saturated soil ¥ sat 20.0 KN/m3
Penetrability of soil in the horizontal direction К 3,000E- 4 m/days
Penetrability of soil in the vertical direction K 3,000E- 4 m/days
Jung's (constant) module Eref 260 KN/m2
Poisson's coefficient V 0.25
Cohesion (constant) Cref 0.9 KPa
Angle of friction 37.0 -
Corner of dilatancy 0.0 -
Correctness of the job of a data set for a cluster is caused by change of its color.
Mohr-Coulomb - Sand
General | Parameters | Interfaces | Material Set Identification: jA AH Material model: jMohrCoulomb Ma terial type: | Drained
750.00
Permeability _
Kc: |0.000 mm/day
500.00 :
K,: jO.OOO mm/day
250.00
Mohr-Coulomb - Sand
General Parameters | Interfaces |
stiffness strength
E ref: luicnnisffEl kN/mm2 Ic
v (nu) : 10.250 «(phi) : J37.000 o
4r(psi) : jo. 000
Alternatives
Gref: |9.600E-05 kN/mrr/ Vs: [7.439 mm/s
E A : (2.880E-04 kN/mm2 Vp: j 12.890 hAj mm/s
Figure 3 - Task to the soil basis of certain properties of soil
"3
General properties 7 unsat |l- 700E-05 '/gat |l. 700E-05
kN/mm1 kN/mm3
After completion of creation of geometrical model will be created the final and element model (mesh). The procedure for creation of a mesh in the Plaxis program is performed completely automatically. By means of this procedure the geometrical model is divided into elements of the main type and compatible structural elements if such are available. At creation of a mesh is considered the provision of points and lines of geometrical model. Thereby, is considered the arrangement of layers, loadings and constructions. The construction method is based on the stable principle of triangulation by means of which there are optimum sizes of triangles which participate in creation of an unstructured mesh. Unstructured mesh do not formed by correctly located elements. However numerical results for such mesh it is usually best than numerical results for the structured mesh having the correct arrangement of elements.
Next, determine the initial conditions. The initial conditions include the initial conditions in groundwater, the initial geometrical configuration and the initial state of effective stresses. In this version, there is no need to enter groundwater conditions, however need the determination of the effective initial stress by using the procedure KO (KO-procedure).
Because this project does not include the water pressure, we turn to the regime of geometric configurations. For the weight of soil we accept the general coefficient equal 1. This means that when constructing the initial stress is taken into account the total weight of the soil.
After creation of the initial tension (Fig. 4) calculation is carried out
1 1 1 1 1 i l ' i i 1' \9 • i i • i 'h i i ' i i i 11 1 1 1 1 1 i i I- 'fi 1
Figure 4 - Field of initial stresses
Were included several calculated stages of modeling of horizontal deformation of tensile along the x axis.
One calculated stage includes modeling of the natural tension caused by gravitation forces.
In the subsequent stages to model of the basis were enclosed the horizontal and stepped deformations imitating horizontal tension. Deformations in the Plaxis program complex are specified in units of force carried per unit area (kN/m2). Values of tension for model of the slab foundation on the soil basis are given in Table 2.
After specifying of the calculated parameters to select nodes or stress points for construction of curves of dependence of displacement on deformations (Fig. 5).
Table 2 - Values of horizontal deformations attached to a model of the pile on soil base
Stage Values of the horizontal strains, s
1 0
2 0.003
3 0.006
4 0.009
5 0.012
After the calculation is completed the results were evaluated by the Output program. In the complete geometric model were obtained displacement and stresses.
Fig. 6 shows the deformed mesh (which is constructed in such scale that can see the displacement) at the end of the selected calculation stage.
Fig. 7 shows the horizontal displacements of all nodes as arrows and areas of displacement with corresponding values.
Figure 5 - Points of stresses for construction of curves of dependences of the displacement on the horizontal deformations
By these values it is possible to observe the horizontal and stepped deformations of the right part of the soil base, which coincide with the deformations of the model experiment presented in the previous Chapter.
Fig. 8 shows the data of the shear stress, by values of which can also be seen that the deformation of the model of single pile is much stronger in the right model from the beginning horizontal and stepped deformations of the soil base.
Eweme total djcement ЗОСПС3 mm (defacement" scaled up 2D OCTCfcries)
Figure 6 - Deformed mesh of the model of single pile at the value s = 3xl0"3 at the end of the selected calculation stage
Toa dSpgaiwts ttJol ExhrMLb3 GDC? mm
Figure 7 - Horizontal displacement of the nodes of the model of single pile on the soil base at the value s = 3x10~3
Figure 8 - Data of the shear stress of the model of the single pile on the soil base
at the value s = 3xl0"3
Next by Output program were given the results of the calculation and were obtained displacements and stresses in a complete geometrical model for the horizontal deformation s = 6xlO"\ 9xlO"\ 12xl0"3.
CONCLUSION
The first and main task of a research is the correct formulation of a task. Formulation of a problem assumes detailed definition of an object of a research. For this purpose it is necessary to define accurately the phenomena and processes which it is supposed to investigate and define the corresponding properties of the environment by means of which they can be described. Besides it is necessary to define geometry of an object and its structure, conditions in which it is and also conditions of loading and duration of the studied process. From that how successful the formulation of a task is, success of her decision depends.
The next step is the choice of a model and determining its parameters. The more complex the model, the more parameters that need to know, i.e. to determine experimentally. The behavior model of the environment is based on the generalization and interpretation of experimental data.
Numerical modeling based on the finite element method, allows to accurately and quickly producing of analytical calculations and forecasting of various geotechnical problems.
REFERENCES
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2015. - № 3—4. С. 51-57.
3 Desai, С. S., Christian, J. Т. Numerical Methods in Geotechnical Engineering. -New York : McGraw-Hill. - 1977. - P. 784.
4 Kozionov, V. A., Aldungarova, A. K. Program of modeling of ground dams work on undermined territories // Международная научно-практическая интернет-конференция «Перспективные инновации в науке, образовании, производстве и транс порте'2013». - Одесса, 2014. - С. 77-81.
5 Kozionov, V. A., Aldungarova, А. К. Program of modeling of ground dams work on undermined territories // Research Bulletin SWorld. Modern scientific research and their practical application. - Odessa. - 2014. - P. 9-17.
6 Finite Elements in Geomechanics (G. Gudehus ed.). - New York: John Wiley. - 1977.-P. 573.
7 Zhukenova, G. A., Kaldanova, В. O. Program of model tests of piles work under horizontal deformations // Proceeding of the International scientific-practical conference «Science, technical regulation and engineering in construction: condition, prospects». - Karaganda, 2016. - P. 265-267.
8 Zhussupbekov A.Zh., Kaldanova B.O., Zhukenova G.A., Muzdybayev Y., Muzdybayeva Т., Dosmukhametova B. Research ofthe mechanical properties of soil basis an equivalent material // Proceeding of the 8th Asian young geotechnical engineers conference «Challenges and Innovations in Geotechnics». - 2016. - P. 61-64.
9 Zhussupbekov, A. Zh., Omarov, A. R., Zhukenova, G. A., Tanyrbergenova, G. K. Geotechnical infrastructures of new capital Astana on problematical soil ground // Proceedings of the 17th Nordic Geotechnical Meeting. -Reykjavik, 2016. - P. 923-930.
10 Aldungarova, A. K., Zhussupbekov, A. Zh., Kozionov, V. A., Lukpanov, R. E., Tanaka, T. Slope Stability Analysis Of The Soil Embankment Reinforced By Geogrid For Reconstructionof Steel Production Plant // Наука и техника Казахстана. - 2016. - № 3- 4. - С. 16-27.
11 Zhussupbekov, A. Zh., Tulegulov, A. D., Omarov, A. R., Zhukenova, G. A., Tanyrbergenova, G. K. The analysis of the piling tests on construction site «The future of the free country» // Proceeding of the 8th Asian young geotechnical engineers conference «Challenges and Innovations in Geotechnics». -
2016,- P. 127-130.
12 Zhussupbekov, A. Zh., Morev, I. O., Omarov, A. R., Borgekova, K., Zhukenova, G. A. Geotechnical considerations of piling testing in problematical soils of West Kazakhstan. - International Journal of GEOMATE. - Japan. -2018.-Vol.15.-P. 111-117.
Material received on 27.02.19.
Жукенова Гюльнара Абаевна
PhD, доцент, «6ндiрiстiк, азаматтык жэне келш к¥рылысы» кафедрасы, С. Торайгыров атындагы Павлодар мемлекеттiк университету Павлодар к., 140008, ^азакстан Республикасы, e-mail: [email protected]. Кенжебек Нурдаулет Кенжебекулы
магистрант, «6ндiрiстiк, азаматтык жэне келш к¥рылысы» кафедрасы, С. Торайгыров атындагы Павлодар мемлекеттш университетi, Павлодар к;., 140008, ^азакстан Республикасы, e-mail: [email protected]. Баймагамбетов Рустем Казымбекович
магистрант, «6ндiрiстiк, азаматтык жэне кeлiк к¥рылысы» кафедрасы, С. Торайгыров атындагы Павлодар мемлекеттш университету Павлодар к., 140008, ^азакстан Республикасы, e-mail: [email protected]. Байжанов Данияр Санатканович
магистрант, «6ндiрiстiк, азаматтык жэне келш к¥рылысы» кафедрасы, С. Торайгыров атындагы Павлодар мемлекеттш университетi, Павлодар к., 140008, ^азакстан Республикасы, e-mail: [email protected]. Материал баспага 27.02.19 тYCтi.
1ргетас Yлгiлерiнiц топырак Heri3iMeH езара эрекет етудщ eKi- елшемдi моделдеу
Ktaзiргi замацда сандыц моделъдеу — топырацтардагы деформациялыц npo^cmepdi зерттеудщ мацызды жэне тез дамып келе жатцан sdici. Есептеу цуатыныц жылдам ecyi осы саланыц дамуына ыцпал етедi. Мэселелер шешудщ табу тэсiлдерi жэне есептердщ жаца aлгоритмдерi жетiлдiрiлуде. Ондаган жылдар бурын дамыган тэстдердщ кейбiрi элсiреуi мен твмендеуi болды жэне ендi цайтадан кецiнен цолданылады. Бул жаца есеп айырысу мYмкiндiктерi, жаца квзцарастар мен проблемалыц мэлiмдемелерге, зерттелетш цубылыстарды кецейтуге байланысты.
Физикалыц npo^^i зерттеудщ негiзгi мацеаты оныц квмегiмен сипатталуы мYмкiн моделдердi цуру болып табылады. Мундай мiндеттердi табысты шешу — бул цубылыстарды тусiндiру цaбiлетi, сондай-ац кез-келген фактор взгерген кезде процестщ дамуын болжау. Талап етшетт дэлджке царай, модель царастырылуы тшс цубылыстардъщ белгiлi бiр жиынтыгын ескередi.
Кiлттi создер: сандыц моделъдеу, iргетaс, соцгы элемент эдiсi, топырац негiзiнiц деформациясы, жуктеу шарттары.
Жукенова Гюльнара Абаевна
PhD, доцент, кафедра «Промышленное, гражданское и транспортное строительство», Павлодарский государственный университет имени С. Торайгырова, г. Павлодар, 140008, Республика Казахстан, e-mail: [email protected].
Кенжебек Нурдаулет Кенжебекулы
магистрант, кафедра «Промышленное, гражданское и транспортное строительство», Павлодарский государственный университет имени С. Торайгырова, г. Павлодар, 140008, Республика Казахстан, e-mail: [email protected]. Баймагамбетов Рустем Казымбекович
магистрант, кафедра «Промышленное, гражданское и транспортное строительство», Павлодарский государственный университет имени С. Торайгырова, г. Павлодар, 140008, Республика Казахстан, e-mail: [email protected]. Байжанов Данияр Санатканович
магистрант, кафедра «Промышленное, гражданское и транспортное строительство», Павлодарский государственный университет имени С. Торайгырова, г. Павлодар, 140008, Республика Казахстан, e-mail: [email protected]. Материал поступил в редакцию 27.02.19.
Двухмерное моделирование взаимодействия моделей фундаментов с грунтовым основанием
В настоящее время численное моделирование является важным и быстро развивающимся методом изучения деформационных процессов в грунтах. Быстрый рост вычислительных возможностей способствует развитию этого направления исследований. Улучшены существующие и разработаны новые алгоритмы расчета и подходы к решению задач. Некоторые из подходов, разработанных десятилетия назад, испытали ослабление интереса и сокращение масштабов и теперь снова широко используются. Это связано с новыми вычислительными возможностями, новыми подходами и постановками задач и расширением классов исследуемых явлений.
Основной целью изучения физического процесса является создание моделей, с помощью которых это можно описать. Успешное решение такой задачи означает возможность объяснить происходящие явления, а также спрогнозировать развитие процесса при изменении любого фактора. В зависимости от требуемой точности в модели учитывается определенный комплекс явлений, которые необходимо учитывать.
Ключевые слова: численное моделирование, фундамент, метод конечных элементов, деформация грунтового основания, условия нагружения.
