V Central Asian Conference on Soil Mechanics and Geotechnical Engineering
Т-воСибГт-в традиционно участвует в большинстве международных геотехнических конференций, проводимых в Средней, Центральной Азии и на Дальнем Востоке. Среди них особо следует выделить уже ставшую регулярной международную конференцию в Самарканде (Узбекистан). Уже третий раз (1-ый – в 2002 г., 2-ой –в 2012 г.) Central Asian Conference on Soil Mechanics and Geotechnical Engineering в Самарканде с успехом организует ведущая научно-проектно-производственная геотехническая компания Узбекистана GEOFUNDAMENTPROJECT Co. Ltd. Organizing Committee V CACSMGE:
Symposium Chair A.Z. Khasanov; Symposium Co-Chair I.I. Usmonkhodjaev; Secretary General Z.A. Khasanov; Technical Secretary Yodgor Obidov; Technical Editor Nozim Yoqubov.
5-7 октября 2022 г. Т-воСибГт-в приняло активное участие в V Central Asian Conference on Soil Mechanics and Geotechnical Engineering.
Члены Т-воСибГт-в выступили на V CACSMGE с 5 докладами и опубликовали их в Proceedings of the V CACSMGE.
- Comparative analysis of the method of calculating the settlements of the foundations according to the field soils tests by a wedging dilatometer
Leonid V. Nuzhdin & Xenia Kozminykh & Аskar Khasanov & Zohir Khasanov
ABSTRACT: The article presents a method for determining the deformations of the soil basement based field soils tests by 100-WD relaxation method. This method allows increasing the accuracy of the calculation of settlements foundations primarily by advancing the reliability of determining the deformation characteristics of soils in the field. The conclusion is made about the possibility and feasibility of using the proposed approach to improve the accuracy of predicting the settlements of structures. A comparative assessment of the results of the calculation of the deformations of the soil basements with observations of precipitation of the foundations of real buildings is performed.
KEYWORDS: soils, settlements, foundations, deformations of soils basement, 100-WD, relaxation method
- Pile field numerical calculation method accounting dynamic load history
Leonid Nuzhdin & Victor Mikhaylov & Leonid Nuzhdin
ABSTRACT: The authors propose a combined approach for a cylindrical geomechanical model of piles by numerical determination of shear rigidity of a multilayer soil cut by a pile. The rigidity of the subsoil under the tip of the pile is calculated analytically as for a stamp on an elastoplastic base. This approach is more visual in the analysis of the stress-strain state of piles and near pile soils. The finite element method simplifies the consideration of the nonlinear properties of materials and the additional swelling or frost effects Dynamic impacts always affect the foundation, which is already experiencing deformations from dead loads. The approach proposed by the authors makes it possible to take into account the conditions of the formation of the stress-strain state of the pile foundation within universal model of the pile cell. After the perception of horizontal static horizontal loads by piles in the form of a beam on an elastic base, proceed to the integral dynamic rigidity of the large pile field, determined on the basis of engineering and geophysical studies. This can be done both by uniformly lowering the horizontal coefficients of the bed along the lateral surface of discrete piles by changing the coefficient α or by lowering the equivalent bending finite stiffness at the level of the pile heads.
KEYWORDS: single pile and pile field settlement, axisymmetric soil and pile FEM model, bending pile cell.
- Calculation of slab foundation settlement on base reinforced with solid vertical elements
Matvey L. Nuzhdin & Andrey B. Ponomaryov & Leonid V. Nuzhdin
ABSTRACT: Calculation of slab foundation settlement on base reinforced with vertical solid elements shows that the values of the qualitative characteristic of the work efficiency (decrease in settlement before and after strengthening), determined by the method of layer-by-layer summation and taking into account the nonlinear nature of the work of the soil in the MIDAS software package, are close to each other. The layer-by-layer summation method can be used for a preliminary assessment of the effectiveness of strengthening the base under the sole of the slab foundation with solid injection bodies formed by group high-pressure injection. It is advisable to determine the reduced deformation modulus of the reinforced layer by the "equal deformations" method.
KEYWORDS: slab foundation, strengthening of foundations, soil foundation reinforcement, high-pressure injection.
- Assessment of the pile bearing capacity from cone penetration test data
Anatoly Polishchuk & Arkadii Petukhov & Natalia Stolyarova
ABSTRACT: The article presents the results of evaluation and comparison of the bearing capacity of piles, determinated by the data of cone-penetration tests (CPT) using I–II probe types and pile load tests, performed as part of the design of a multi-storey residentiall complex in Tomsk. It is shown that in water-saturated clay soils, the average deviation of the bearing capacity of piles according to CPT data from the results of full-scale pile loading test was 47% for I probe type and 18% for II probe type. The results of testing with II probe type turned out to be closest to the actual values of the bearing capacity. The bearing capacity of piles, determinate by the results of CPT with I probe type exceeds by 1.5 times the bearing capacity of piles obtained using II probe type.
KEYWORDS: cone-penetration tests, bearing capacity of piles, pile load tests, electrical and mechanical probes.
- Verticality of boreholes
Roman Melnikov & Prof. Yakov Pronozin & Elena Bragar
ABSTRACT: The study contains the problem of the borehole shape of during drilling. Usage of a drilling bit and tubular or screw rods is traditional and most common drilling methods. The requirement of "verticality" for boreholes in the drilling process is necessary to comply with design solutions and design schemes. At the same time, the actual implementation of this important quality is often very difficult. An analysis of the regulatory documentation is carried out to ensure the requirement during conducting geotechnical investigations, and during installing pile foundations made in the ground: bored piles and continuous flight auger piles (CFA). Data about the researchers in the field of assessing of bending of the pile axis are presented for CFA piles. The article presents the results of field studies of the borehole verticality at two investigation sites. At the first site, a borehole was drilled with a depth of 9.0 m, at the second site, ten boreholes were drilled with a depth of 25.0 m. The spatial position of the boreholes was determined by an inclinometer. The results of the measured verticality deviations of the boreholes are presented on the spatial graph for clear visibility. A conclusion is made about the influence of the borehole shape on its vertical projection during conducting of geotechnical investigations. A series of comparative numerical calculations was performed using the Midas GTS NX program to assess the effect of the verticality deviations of the boreholes during installing bored piles on their bearing capacity. A single pile action in the ground was simulated for the pressing and pulling loads. It is concluded that the shape of the borehole influences on the single pile action in the ground.
KEYWORDS: deviation, micropile, soil drilling, vertical pile, pile bearing capacity, pile axis.
Ассоциированные члены Т-воСибГт-в представили на V CACSMGE 4 доклада, материалы которых вошли в Proceedings of the V CACSMGE.
- Analysis of the theories of soil strength and recommendations for their improvement
Khasanov A. Z & Khasanov Z. A.
ABSTRACT: The paper deals with the analysis of known theories of soil strength. Based on this analysis, a new concept of the theory of soil strength is proposed, which makes it possible to take into account the fundamental parameters of soil strength: the internal friction angle, the specific cohesion, and the lateral pressure coefficient. Analytical expressions are given that make it possible to determine the stress state on areas deviated with respect to the principal stresses. The definition of the physical essence of the concept of "coefficient of lateral pressure for soils" is given. An example of the implementation of the proposed model and its graphical application are given.
- Foundations on artificial bases stabilized also (strengthened) by vertical armo – elements (VAE) with a seismic-protective damping layer
B. Kurbanov & Z.A. Khasanov & A.Z. Khasanov
ABSTRACT: The paper examines the issues of bases from the compacted soil pads, pile foundations and bases stabilized by vertical reinforcing elements. The results of the modeling of vertical armo-elements on loess subsiding soils and foundation pads are given in the paper. The methods of determining of the basic calculating parameters of bearing armo-element capacity and foundation pad are presented by the authors. The results of practical use of this method of bases and foundation construction in soil conditions of Uzbekistan are also given in the paper.
- Calculation and design of Anchor Piles in the soil conditions of Uzbekistan
Khasanov A.Z. & Toshkhojayev A.U. & Burkhanov B.A.
ABSTRACT: The article deals with the issues of practical methods of installation of anchor structures necessary for the construction of underground structures, retaining walls, slopes and as supports for cable-stayed structures, including for the construction of light tent structures. The results of experimental studies of the bearing capacity of the most common types of anchor supports are presented.
- Pressuremeter with a working body made of sand to determine the deformation characteristics of loess soils.
Nabiyeva N. & Khasanov A.Z.
ABSTRACT: The paper discusses the new method for determining the deformation and subsidence features of soils in the field. The paper describes a new form of the pressuremeter. For the proposed type of pressuremeter, the method and the analytical solution for determining the values of soil deformability are proposed.
KEYWORDS: Stresses, modulus of deformation, soil pressure, base deformations, stress- strain state.
Еще 3 доклада сделали на V CACSMGE председатель Экспертно-консультационного совета Т-воСибГт-в профессор А.Б. Пономарев, председатель International Advisory Committee Т-воСибГт-в профессор Eun Chul Shin и председатель International Promotion Committee Т-воСибГт-в профессор Askar Zhussupbekov. Материалы этих докладов также опубликованы в Proceedings of the V CACSMGE.
- Some results of geotechnical monitoring of a residential complex on a sloping territory
Ponomarev A.B & Zakharov A.V & Sursanov D.N & Sazonova S.A & Shalamova E.A.
ABSTRACT: The article presents the results of geotechnical monitoring of a residential complex being built in difficult engineering and geological conditions at the site of the development of the slopes of the processes. The purpose of geotechnical monitoring was timely detection of defects and prevention of negative processes to ensure the preservation of the operational qualities of the constructed and existing buildings, structures, as well as assessment of the impact of new construction on the surrounding buildings and structures during construction work. Based on the analysis of the measurement results of geotechnical monitoring, an adjustment was made on the composition and technology of construction work and their comparison with the predicted and limit values.
- Experimental behavior analysis of the controlled low strength material mixed with fly ash and paper ash
Eun Chul Shin & Jeong Ku Kang & In Hwan Lee
ABSTRACT: This research describes the evaluation results on the strength characteristics of CLSM using sand, fly ash and paper ash, in order to develop a CLSM that can prevent sewer pipe damage. The unconfined compressive strength test and flowability test were carried out with respect to the mix design conditions of CLSM. The flowability test results indicate that the water contents, which can satisfy the flowability criteria, are satisfied from 24% to 32% with regard to the mix design condition. The results of unconfined compressive strength test show that the strength incremental ratio is high between 1 and 7 days of curing time, and the strength at this time is more than about 50% of the strength at 28 days of curing time. The strength of CLSM is greatly influenced by fly ash. However, it is analyzed that the mixture of paper sludge ash is required when the reference strength of CLSM is considered. Although the strength of the high cement ratio is higher than that of the low cement, a cement ratio of 5% would be a reasonable mix design condition of CLSM.
KEYWORDS: collapse around underground, backfill material, fly ash, paper ash, unconfined compressive strength.
- Methods of testing piles of Megastructures on problematical soil grounds of Kazakhstan
Askar Zhussupbekov & Abdulla Omarov & Askar Yessentayev & Aizhan Zhankina & Bibigul Abdrakhmanova & Abilkhair Issakulov
ABSTRACT: This paper describes the general aspects of the pile foundation concept, technologies as CFA and DDS used in Mega-projects of Kazakhstan. Just as every civilization in the history is originated from the riverside, so the city of Nur-Sultan - Capital of Kazakhstan has been developed around the Ishim River. Also the paper illustrates comparisons between the existing field pile test results with the results of PDA and SLT by GOST. Such advanced technologies as PIT and geo-monitoring are also mentioned. Also, the paper considered the testing of piles at the Megaproject the Big Almaty Ring Road (BAKAD). Also high rise building such Palace of Peace, Abu -Dhabi Plaza, Expo2017, Ministry of Transportation Buildings constructions site and other many structures founded in problematical soil ground of Nur-Sultan city. These unique buildings need performing of deep driving and boring piling foundations. For designing of piling foundations on difficult soils are important investigations of behaviour of piles by using of dynamic, static, O-cell, integrity piling tests. These investigations of interaction of piles with soil ground of new capital are important for understanding of mechanism of working of different piles on soft and hard soils of Nur-Sultan.
KEYWORDS: Geo-monitoring; BDSLT, SLT, DLT
Proceedings of the V CACSMGE can be viewed here.