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Wyświetlanie 1-15 z 36
Tytuł:
Torsional shear device for testing the dynamic properties of recycled material
Autorzy:
Gabryś, K.
Sas, W.
Soból, E.
Głuchowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/178444.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
torsional shear test
shear modulus
material damping
recycled material
Opis:
From the viewpoint of environmental preservation and effective utilization of resources, it is beneficial and necessary to reuse wastes, for example, concrete, as the recycled aggregates for new materials. In this work, the dynamic behavior of such aggregates under low frequency torsional loading is studied. Results show that the properties of such artificial soils match with those reported in the literature for specific natural soils.
Źródło:
Studia Geotechnica et Mechanica; 2016, 38, 4; 15-24
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Shear Tests of Bolt Rods Under Static and Dynamic Loading
Autorzy:
Pytlik, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/178659.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rock bolt
laboratory bolt test
static single shear test
dynamic single shear test
shear work
Opis:
This article presents the methodology and results of single shear tests of bolt rods under dynamic impact loading generated by means of a drop hammer. Comparative analysis was also performed for bolt rod load capacity, stress and shear work under static and dynamic (impact) loading. The developed method of single shear testing of bolt rods under impact loading makes it possible to obtain repeatable test results concerning maximum bolt rod shearing force, shear stress and shear work values. Comparative shear tests of four types of bolt rods under static and impact loading showed that the APB-type bolt rods made of AP770 steel, which was characterised by having the highest strength, exhibited the greatest shear work. AM22- type bolt rods exhibited a very similar work value. Though the AM22-type bolt rods made of A500sh steel demonstrated lower strength than the APB-type bolts, as well as a smaller diameter and cross section, they dissipated the impact energy better thanks to their higher plasticity. This could indicate the direction of optimisation for bolt rods in order to increase their impact strength. Mathematical relationships were also formulated for selected tests, describing the real single shear courses F d =f(t ) of bolts under impact loading. The obtained relationships could be applied in the load assessment process of bolt rods intended for use under roof caving, tremor and rock burst conditions.
Źródło:
Studia Geotechnica et Mechanica; 2020, 42, 2; 151-167
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interpretation of shear modulus degradation tests
Autorzy:
Srokosz, P.
Dyka, I.
Bujko, M.
Powiązania:
https://bibliotekanauki.pl/articles/178491.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
torsional shear
back analysis
cluster analysis
shear modulus
small strains
Opis:
The problem is a continuation of the research conducted at the University of Warmia and Mazury in Olsztyn, Institute of Building Engineering. It concerns the development of methods for the interpretation of the shear modulus measurements based on the tests conducted on a torsional shear (TS) apparatus. The issue has significant importance in determining the deformation parameters, essential to perform numerical simulations of the interaction between a geotechnical structure and the subsoil. The purpose of this study was to conduct a comparative analysis of the various methods of interpretation of research results based on direct and reverse analysis, as well as automated classification of the first cycle of the relationship between the shear stress and the shear strain components obtained from the TS test. The methodology for verification of the presented interpretative methods consists in carrying out a series of laboratory tests on non-cohesive and cohesive samples of different granulation and state parameters. The course of the research includes the following steps: elaboration of the granulometric composition of several samples of soil, determination of soil index properties and execution of TS tests. Various methods of interpretation of obtained results were taken into account, in addition to conducting a comparative analysis. The study used a non-standard interpretation approach consisting of analysing onefourth of the hysteresis loop of the first load-unload cycle of the tested samples. The obtained results confirmed the hypothesis that it is possible to estimate the degradation value of the shear modulus based on a part of the TS test results carried out under quasi-monotonic load conditions. The proposed methods of interpreting test results have confirmed their high usefulness, which is devoid of the uncertainty associated with standardised resonant column/TS testing.
Źródło:
Studia Geotechnica et Mechanica; 2018, 40, 2; 125-132
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-ray microtomography (μCT) as a useful tool for visualization and interpretation of shear strength test results
Autorzy:
Stefaniuk, D.
Tankiewicz, M.
Stróżyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/178870.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
X-ray microtomography
shear strength
shear plane
fine-grained soil
triaxial test
Opis:
The paper demonstrates the applicability of X-ray microtomography (μCT) to analysis of the results of shear strength examinations of clayey soils. The method of X-ray three-dimensional imaging offers new possibilities in soil testing. The work focuses on a non-destructive method of evaluation of specimen quality used in shear tests and mechanical behavior of soil. The paper presents the results of examination of 4 selected clayey soils. Specimens prepared for the triaxial test have been scanned using μCT before and after the triaxial compression tests. The shear strength parameters of the soils have been estimated. Changes in soil structure caused by compression and shear failure have been presented as visualizations of the samples tested. This allowed for improved interpretation and evaluation of soil strength parameters and recognition of pre-existing fissures and the exact mode of failure. Basic geometrical parameters have been determined for selected cross-sections of specimens after failure. The test results indicate the utility of the method applied in soil testing.
Źródło:
Studia Geotechnica et Mechanica; 2014, 36, 4; 47-55
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of randomly distributed polypropylene fiber reinforcement on the shear behavior of sandy soil
Autorzy:
Benziane, Mehdi Missoum
Della, Noureddine
Denine, Sidali
Sert, Sedat
Nouri, Said
Powiązania:
https://bibliotekanauki.pl/articles/178213.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sand
direct shear box tests
polypropylene fibre
shear strength
normal stress
relative density
Opis:
The inclusions of geosynthetic materials (fibers, geomembranes and geotextiles) is a new improvement technique that ensures uniformity in the soil during construction. The use of tension resisting discreet inclusions like polypropylene fibers has attracted a significant amount of attention these past years in the improvement of soil performance in a cost-efficient manner. A series of direct shear box tests were conducted on unreinforced and reinforced Chlef sand with different contents of fibers (0, 0.25, 0.5 and0.75%) in order to study the mechanical behavior of sand reinforced with polypropylene fibers. Samples were prepared at three different relative densities 30%, 50% and 80% representing loose, medium dense and dense states, respectively, and performed at normal stresses of 50, 100 and 200 kPa. The experimental results show that the mechanical characteristics are improved with the addition of polypropylene fibers. The inclusion of randomly distributed fibers has a significant effect on the shear strength and dilation of sandy soil. The increase in strength is a function of fiber content, where it has been shown that the mechanical characteristics improve with the increase in fiber content up to 0.75%, this improvement is more significant at a higher normal stress and relative density.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 3; 151-159
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A laboratory investigation on shear strength behavior of sandy soil: effect of glass fiber and clinker residue content
Autorzy:
Bouaricha, L.
Djafar Henni, A.
Lancelot, L.
Powiązania:
https://bibliotekanauki.pl/articles/178431.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
direct shear test
glass fibers
clinker residue
peak shear stress
sand
normal stress
cohesion
frictional angle
Opis:
A study was undertaken to investigate the shear strength parameters of treated sands reinforced with randomly distributed glass fibers by carrying out direct shear test after seven days curing periods. Firstly, we studied the fiber content and fiber length effect on the peak shear strength on samples. The second part gives a parametric analysis on the effect of glass fiber and clinker residue content on the shear strength parameters for two types of uniform Algerian sands having different particle sizes (Chlef sand and Rass sand) with an average relative density Dr = 50%. Finally, the test results show that the combination of glass fiber and clinker residue content can effectively improve the shear strength parameters of soil in comparison with unreinforced soil. For instance, there is a significant gain for the cohesion and friction angle of reinforced sand of Chlef. Compared to unreinforced sand, the cohesion for sand reinforced with different ratios of clinker residue increased by 4.36 to 43.08 kPa for Chlef sand and by 3.1 to 28.64 kPa for Rass sand. The feature friction angles increased from 38.73° to 43.01° (+4.28°), and after the treatment, clinker residue content of soil evaluated to 5% (WRC = 5%).
Źródło:
Studia Geotechnica et Mechanica; 2017, 39, 4; 3-15
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of shear-induced breakage and reflocculation on the floc structure, settling, and dewatering of coal tailings
Autorzy:
Fan, Yuping
Ma, Xiaomin
Song, Shuai
Dong, Xianshu
Chen, Ruxia
Dong, Yingdi
Powiązania:
https://bibliotekanauki.pl/articles/110405.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal tailings
floc structure
shear
settling
dewatering
Opis:
Flocculation is crucial for the treatment of coal tailings in industries. In this paper, the effects of shear-induced breakage and reflocculation of the floc, settling, and dewatering of coal tailings were investigated. The results show that as shear strength increases, the settling velocity of flocculated tailings decreases. A shear rate of 200 rpm (170.6 s-1) leads to the loss of half the settling velocity. However, at high dosage cases, 200 rpm-300 rpm shear could improve the clarity of the supernatant. Small particles are flocculated preferentially, especially for particles below 10 µm. With the increase in dosage, the critical particle size for the occurrence of flocculation increases. The chaos index proposed can quantitatively reflect the degree of flocculation or reflocculation of coal tailings. At high dosage conditions, shear could enhance the dewatering performance of flocs by reconstructing the filter cake. Controlling the structure of flocs by dosage and shear strength can help obtain appropriate settling, clarifying, and dewatering performance of coal tailings.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 2; 363-373
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of shear strength in silty soils
Autorzy:
Stefaniak, K.
Powiązania:
https://bibliotekanauki.pl/articles/178390.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
shear strength
cone factor Nkt
silty soil
Opis:
The article presents a comparison of shear strength values in silty soils from the area of Poznań, determined based on selected Nkt values recommended in literature, with values of shear strength established on the basis of Nkt values recommended by the author. Analysed silty soils are characterized by the carbonate cementation zone, which made it possible to compare selected empirical coefficients both in normally consolidated and overconsolidated soils.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 2; 51-55
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
O występowaniu i wpływie na trwałość konstrukcji drewnianych, zmiennego w czasie modułu sztywności poprzecznej G
On the occurrence of the time-dependent shear modulus G and its effect on the durability of wooden structures
Autorzy:
Misztal, Barbara
Powiązania:
https://bibliotekanauki.pl/chapters/2194752.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
moduł sztywności poprzecznej
włókno drzewne
lepkosprężysta matryca
siła poprzeczna
shear modulus
wooden fibre
visco-elastic matrix
shear force
Opis:
W opracowaniu omówiono historyczne rozwiązania konstrukcji stosowane w celu zmniejszenia wpływu sił poprzecznych. Zaprezentowano model drewna jako naturalnego kompozytu włóknistego, zbudowanego z włókien umieszczonych w lepkosprężystej matrycy. Opisano badania na modelach wspornikowych z drewna, w celu pokazania trendu zmian ugięć i zmniejszenia wartości modułów sprężystości podłużnej E i poprzecznej G zaobserwowaną w czasie 72 godzin. Wskazuje to na osłabienie zamocowania włókien w lepko sprężystej matrycy po długim czasie eksploatacji konstrukcji i powoduje wzrost przemieszczenia poprzecznego.
The paper discusses some historical solutions of wooden structures used in order to reduce the impact of shear forces. A model of wood as a natural fibrous composite, built of fibres located in a visco-elastic matrix, was presented. The testing on support models made of wood was described in order to show the trend of variations of deflections and that of the reduction in the value of moduli of longitudinal elasticity E and shear moduli G surveyed during 72 hours. The trend demonstrated evidences a weakening of the fastening of fibres in the visco-elastic matrix during the operation of the wooden structure, also an increase in shear forces leading to the reduction in the global load capacity of an element or a system made of wood.
Źródło:
Dziedzictwo architektoniczne. Ochrona i badania obiektów zabytkowych; 17-25
9788374931519
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress-dilatancy for soils. Part IV: Experimental validation for simple shear conditions
Autorzy:
Szypcio, Z.
Powiązania:
https://bibliotekanauki.pl/articles/178165.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soils
dilatancy
critical state
frictional state
simple shear
Opis:
This paper validates the frictional state theory using published experimental data from simple, direct and ring shear tests. Simple shear is treated as a special case of plane strain conditions. In order to define complete stress and strain, additional assumptions are made: in the direct shear and ring shear tests, simple shear is assumed to occur in the shear band. For Φ° = Φ’ϲϑ = Φ’r, the stress-dilatancy relationship obtained from the frictional state theory is similar to the relationships proposed by Taylor and Bolton. Further experiments, especially those that use a hollow cylindrical shear apparatus, are necessary to fully validate the frictional state theory in simple shear conditions.
Źródło:
Studia Geotechnica et Mechanica; 2017, 39, 1; 81-88
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Usefulness of the CPTU method in evaluating shear modulus G0 changes in the subsoil
Autorzy:
Młynarek, Zbigniew
Wierzbicki, Jędrzej
Lunne, Tom
Powiązania:
https://bibliotekanauki.pl/articles/1845148.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
shear modulus G0
CPTU
non-cohesive soil
Opis:
This article contains the analysis of the correlation between the cone resistance qc from CPTU tests and shear modulus G0 determined from seismic tests SDMT and SCPTU. The analysis was performed for sands located in Poland, characterised by differential grain size distribution and origin. The significant impact of the independent variables; grain size, preconsolidation stress σ’p, geostatic vertical stress σ’v0 and relative density index on the dependencies analysed, were examined in three stages. Firstly, a general relationship between the cone resistance and shear modulus G0 was established; in the second stage, an analysis was carried out in selected groups of subsoil; and in the third stage, the influence of other independent variables was taken into account. In each stage, the functional form of the dependency was determined, and their statistical significance was assessed throughout coefficient of determination R2. For more variables, multivariable regression analysis was applied for assessment. Conducted analysis showed that the overall view of the relation between the cone resistance qc and shear modulus G0 has low evaluation of the statistical significance. This fact is consistent with the theoretical assessment of this relationship. To obtain a satisfactory assessment of this dependency, it is necessary to construct empirical equations for individual groups of soil, taking into account other independent variables; preconsolidation stress σ’p, vertical stress σ’vo and relative density index. This approach allows to assess the local correlation relationship, which is very useful during the geological project.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 3; 195-205
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved formulation of the Hardening Soil model in the context of modeling the undrained behavior of cohesive soils
Autorzy:
Truty, A.
Obrzud, R.
Powiązania:
https://bibliotekanauki.pl/articles/178469.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soil constitutive modeling
undrained shear strength
deep excavations
Opis:
The analysis of an important drawback of the well known Hardening Soil model (HSM) is the main purpose of this paper. A special emphasis is put on modifying the HSM to enable an appropriate prediction of the undrained shear strength using a nonzero dilatancy angle. In this light, the paper demonstrates an advanced numerical finite element modeling addressed to practical geotechnical problems. The main focus is put on serviceability limit state analysis of a twin-tunnel excavation in London clay. The two-phase formulation for partially saturated medium, after Aubry and Ozanam, is used to describe interaction between soil skeleton and pore water pressure.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 2; 61-68
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the heterogeneity of a dump soil on the assessment of its selected properties
Autorzy:
Olesiak, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/1845138.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
dump soil
soil properties
shear strength
laboratory test
heterogeneity
Opis:
This article concerns the assessment of selected physical and mechanical properties of a dump soil. The dump soil is a specific soil with a very heterogeneous internal structure. Next to each other, there may be lumps and crumbs of cohesive soils mixed with non-cohesive soils accompanied by a very diverse admixture of organic substance. In addition, the soil in the waste dump, in spatial terms, may significantly differ in consistency and density. This is the result of the process of forming a dump soil, which takes place in three stages: excavation, transport and dumping. A heterogeneous soil deposited within the waste dump is subject to further processes: consolidation, compaction and creeping. Changes occurring in the course of these processes have a significant impact on the development of the properties of the dump soil. Due to the large diversity of the tested soils, the results of their properties were divided into two groups, based on type and consistency of soil. This allows us to estimate the selected properties of the dump soil only on the basis of their macroscopic analysis.
Źródło:
Studia Geotechnica et Mechanica; 2020, 42, 3; 263-275
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seismic codes based equivalent nonlinear and stochastic soil structure interaction analysis
Autorzy:
Guellil, Mohamed Elhebib
Harichane, Zamila
Çelebi, Erkan
Powiązania:
https://bibliotekanauki.pl/articles/1845159.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
shear modulus
damping
uncertainties
linear iterative method
seismic code
Opis:
The aim of this study is to consider the effects of the variation of shear modulus ratio (G/G0) and damping ratio (ξ) of soil, obtained by a linear iterative method based on the design spectra of seismic codes, the soil environment in terms of uncertainties in shear modulus using Monte Carlo simulations and the foundation damping (ξf) of flexible base for analyses of the Soil-Structure Interaction (SSI) problems. A squat structure with circular shallow foundation resting on a soil layer over a homogeneous half-space is studied by using cone model and considering seismic zone effect on structural response. Firstly, after showing the effects of the correction of G and ξ on impedance functions and the responses of soil-foundation-structure system, a study is carried out to compare these effects to those of the modelling of uncertainties in shear modulus as random variations. Secondly, a comparative analysis on design response spectra and base shear forces was carried out for four seismic codes (Algerian Seismic Rules RPA99- 2003, Eurocode 8-2004, International Building Code IBC-2015 and Indian Code IS-1893-2002) considering the three cases of SSI: SSI effects (initial G and ξ), nonlinear SSI (corrected G and ξ) and stochastic SSI (random G with COV = 20%) compared to the fixed base case. Results show that the correction of G and ξ, according to the equivalent nonlinear method in all the cases, leads to a remarkable decrease in peak responses but show a huge amount of reduction in the second study for IBC-2015 and IS-1893-2002 codes compared to the other codes.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 1; 1-14
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bearing capacity of the working platform with kinematic method
Autorzy:
Białek, K.
Bałachowski, L.
Powiązania:
https://bibliotekanauki.pl/articles/178343.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soft soil
undrained shear strength
limit state
failure mechanism
Opis:
Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 1; 3-8
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 36

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