Current Topics at the Institute of Geotechnical Engineering
Table of contents
Working Group of Applied Geology
Chair of Soil Mechanics and Foundation Engineering
For details of this topic please contact Mr. Uhlig.
Keywords
laboratory tests, literature, fall cone test
Research Fellow
NameDr.-Ing. Markus Uhlig
Coordinator Laboratory; Courses: BIW4-10, BIW3-04
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Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 or in the laboratory George-Bähr-Str. 1a
01069 Dresden
The critical state in the soil is defined as the state in which the stresses and the volume of the soil remaind constant. For the determination of the soil parameters in critial state usually drained triaxial tests (CD) are beeing performed. The procedure of the CD test is very complex and time consuming.
Within the scope of this work the newly developed simple shear test should be used for the determination of the critical state parameters for coarse grained soils. Three different sands should be tested. Additionally, the new procedure should be validated by testing the used sands in the drained triaxial test.
Research Fellow
NameBožana Baćić M. Sc.
Research, Course: BIWE-14, BIWO-07, BIW4-62
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Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 George-Bähr-Str. 1a
01069 Dresden
Performance of triaxial tests in soil mechanics laboratories represents a common daily task. Usually soil specimens are tested under stresses which are higher than 100 kPa. Testing at stresses lower than 100kPa is still a challenging task.
Withing this work a soil behaviour under small stresses in undrained conditions should be investigated. For this purpose, various sands should be tested in a newly developed experimental setup for investigations of a pore water pressure build-up. The soil behaviour under different stress levels and (optionally) reconstitution methods should be also checked. All performed triaxial tests need to be evaluated and the results analysed.
Research Fellow
NameBožana Baćić M. Sc.
Research, Course: BIWE-14, BIWO-07, BIW4-62
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Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 George-Bähr-Str. 1a
01069 Dresden
Soil is usually a multi-phase material, including solid soil grains, air and water in the pore space. In dry condition, the mechanical properties of the soil mainly depend on the soil skeleton, as the pore space is only occupied by air whose density and stiffness can be ignored when compared with the soil skeleton. On the other hand, when the pore space is occupied by water or air-water mixture, the mechanical properties of the soil depend not only on the soil skeleton but also on the compressibility of the fluid in the pore space.
The focus of this work is to determine the compressibility of the completely and partially de-aired water. For this purpose, specimens consisting glass beads should be installed in a triaxial chamber and by means of the B-test need to be tested on their compressibility. Additionally, the compressibility of the de-aired water will be studied in a cylinder with the pressure piston.
Research Fellow
NameBožana Baćić M. Sc.
Research, Course: BIWE-14, BIWO-07, BIW4-62
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 George-Bähr-Str. 1a
01069 Dresden
For details of this topic please contact Mr. Uhlig.
Keywords
Labortory testing, photogrammetry
Research Fellow
NameDr.-Ing. Markus Uhlig
Coordinator Laboratory; Courses: BIW4-10, BIW3-04
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 or in the laboratory George-Bähr-Str. 1a
01069 Dresden
For details of this topic please contact Mr. Uhlig.
Keywords
literature, laboratory testing, microscopy
Research Fellow
NameDr.-Ing. Markus Uhlig
Coordinator Laboratory; Courses: BIW4-10, BIW3-04
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 or in the laboratory George-Bähr-Str. 1a
01069 Dresden
In laboratory testing an isotropic consolidated triaxial test is common. But in situ mostly a anisotropic state can be found.
In this work triaxial tests should be performed with anisotropic and isotropc consolidation. The aim is to determine the influence of anisotopic consolidation.
Furthermore a program for controlling the triaxal apparatus can be developed.
The work can be done as master thesis or project work. For the implantation of the programme to control the apparatus the knowledge of programming is required.
Keywords
Literature, triaixal testing, programming
Keywords
Literature, triaixal testing, programming
Research Fellow
NameDr.-Ing. Markus Uhlig
Coordinator Laboratory; Courses: BIW4-10, BIW3-04
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 or in the laboratory George-Bähr-Str. 1a
01069 Dresden
An overconsolidated soil was exposed to a higher vertical pressure in the past, than the actual ones. This preconsolidation may have different reasons, e.g. Excavation of overlying layers of soil, geologic history or else. For samples from site, this preconsolidation pressure is sometimes unknown.
The aim of this thesis is to determine the preconsolidation pressure of undisturbed samples with different methods. Therefore artificial samples should be consolidated and released. With the help of different experimental methods the former consolidation pressure should be determined.
As a new approach it should be checked, if the preconsolidation pressure can be determined due to a change in shear wave velocity of the material. Therefore experiments with bender-elements in a trixial cell should be conducted.
Research Fellow
NameDr.-Ing. Markus Uhlig
Coordinator Laboratory; Courses: BIW4-10, BIW3-04
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 or in the laboratory George-Bähr-Str. 1a
01069 Dresden
The mechanical behaviour of mixed-grained soils is determined by the ratio of fine and coarse grains. For a low fines content, the load-bearing grain structure is completey consisted of coarse grains whereas a high fines content results in the coarse grains to "swim" inside the fine grains. Consequently, depending on the composition of the binary mixture, the mechanical behaviour is either governed by the coarse or the fine grains.
in order to further analyse the influence of the fines content, mechanical tests are performed using binary mixtures of fine and coarse sand in different ratios. Furthermore, the influence of the fine sand content on the density is investigated. The following laboratory tests are performed within the scope of this work:
- density tests
- oedometer tests
- shear tests
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Wissenschaftliche Mitarbeiterin
NameDipl.-Ing. Selma Schmidt
Forschung, Lehre: BIW2-03, BIWE-04
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Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), 106 George-Bähr-Str. 1a
01069 Dresden
The behaviour of a mixed-grained soil is strongly dependent on its composition. Usually, the fine grains are assumed to have no influence on the soil behaviour below a certain fines content, which is typically quite high. But is this assumption really true?
To answer this question, the influence of the fines content on the fabric of the soil is analysed. For this purpose, binary mixtures of coarse and fine sand are prepared at different ratios. Because the fabric of a soil significantly influences its behaviour, the influence of the fine sand content on the soil behaviour can be derived from this analysis.
The preparation of the soil specimens is especially challenging in this regard. While the soil fabric should be as realistic as possible, it also sould not change during the investigation. In situ, cohesive forces act on the sand grains due to the pore water. Unfortunately, when using water for the specimen preparation, the water can evaporate during the investigation and the fabric can change.
The goal of this work is the development of a suitable procedure for the preparation of binary specimens. The influence of the preparation method on the soil fabric is determined with the help of microscopy. The analysis focuses on specimens prepared with:
- synthetic resins
- oil
- sugar solutions
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Wissenschaftliche Mitarbeiterin
NameDipl.-Ing. Selma Schmidt
Forschung, Lehre: BIW2-03, BIWE-04
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Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), 106 George-Bähr-Str. 1a
01069 Dresden
The Cone penetration test is commonly used indirect field test to determine geotechnical values. Moreover the soil type can be determined. Hereby a lot of method are available in the literature.
In this work some of this methods should be implemented in a routine. Furthermore empirical methods to determine the layer-effects could be implemented.
Additionally a method to compare the soil types from CPT and the classification results on samples could be developed.
This work can be done within a master thesis or in shorter from in a project work. it is a precondition the have knowledge about programming. For this work there existing some ideas how the soil type methods and to build the comparison tool can be developed.
Keywords
Literature, determination of cone penetration tests, programming
Research Fellow
NameDr.-Ing. Markus Uhlig
Coordinator Laboratory; Courses: BIW4-10, BIW3-04
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 104 or in the laboratory George-Bähr-Str. 1a
01069 Dresden
At the Institute of Geotechnical Engineering, the behaviour of a mixed-grain soil is currently being intensively studied. When the grain size distribution of this soil was determined, it was found to be subject to scattering.
Grain size distribution band of the mixed-grained soil
The work will therefore investigate how the grain size distribution of the soil influences the mechanical behaviour and hence the material parameters of the hypoplastic material model (without intergranular strain). For this purpose oedometer and triaxial tests will be carried out in the laboratory on self-made mixtures representing both the upper and lower limits of the grain size distribution. The results will then be used to calibrate the material parameters of the hypoplastic material model.
The aim of the work should be to work out the uncertainty in the material parameters due to the grain size distribution and to give a range for each model parameter.
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Wissenschaftlicher Mitarbeiter
NameDipl.-Ing. Sebastian Ullmann
Forschung, Modul BIW2-03
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Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 106 George-Bähr-Str. 1a
01069 Dresden
The Institute of Geotechnical Engineering focuses on the development and verification of material models for soils. To this end, a large-scale model test is currently being constructed and instrumented with numerous sensors. The aim is to be able to investigate soil behaviour not only in typical small-scale laboratory tests, but also under in-situ conditions with natural influences such as temperature changes, changes in the degree of soil saturation, but also due to cyclic traffic loads.
To accompany the construction of the large-scale test, the thesis will develop a numerical model of the large-scale test, which can then be used to investigate the behaviour of advanced material models.
The simulations will be carried out using the software numgeo, which has been developed specifically for geotechnical applications.
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Wissenschaftlicher Mitarbeiter
NameDipl.-Ing. Sebastian Ullmann
Forschung, Modul BIW2-03
Send encrypted email via the SecureMail portal (for TUD external users only).
Chair of Soil Mechanics and Foundation Engineering
Visiting address:
Neuffer-Bau (NEU), NEU 106 George-Bähr-Str. 1a
01069 Dresden