- Détails du magazine
- Format
- Magazine
- eISSN
- 2083-831X
- Première publication
- 09 Nov 2012
- Période de publication
- 4 fois par an
- Langues
- Anglais

#### Chercher

#### Research Article

Accès libre

#### Skin and Toe Resistance Mobilisation of Pile During Laboratory Static Load Test

Pages: 1 - 5

#### Résumé

This article shows the mathematical method to determine the lateral stress on the shaft and toe resistance of pile using the new approach. The method was originally invented by Meyer and Kowalow for the static load test. The approximation curve was used for the estimation of both settlement curve and toe resistance curve of the pile. The load applied at the head of the pile is balanced by the sum of two components: the resistance under the toe of the pile and the skin friction. Therefore, the settlement curve is compilation of two factors: the skin friction curve and the resistance under toe curve. The analysis was based on the verification of the methods using laboratory experiments, that is, static load tests. The results of the research allowed to determine the relationship between parameters of the Meyer–Kowalow curve. On the basis of the relationships, it was possible to determine the skin friction and the toe resistance of the pile. Mathematical analysis of curve parameters allowed to determine the influence of the toe resistance on the settlement.

#### Mots clés

- Pile
- static load test
- skin friction
- toe resistance

#### Résumé

In this article, the stress–dilatancy relationship for crushed latite basalt is analysed by using _{pt}_{pt}^{p}

#### Mots clés

- ballast
- dilatancy
- frictional state
- breakage

Accès libre

#### Numerical 3D simulations of seepage and the seepage stability of the right-bank dam of the Dry Flood Control Reservoir in Racibórz

Pages: 11 - 20

#### Résumé

This article presents the results of numerical simulations of seepage through the body of the dam and the reservoir bed. The purpose of this study was to analyse the seepage stability during a flood as well as the impact on seepage stability of the diaphragm wall and gravel columns, on which the dam body is founded in selected segments. Simulations were conducted for three different locations, and the following 3D models of the dum were prepared:

a model containing the front and right-bank part of the dam, for which no diaphragm wall, gravel columns and drainage ditch were provided for

a model of a segment of the right-bank dam including a diaphragm wall, drainage ditch and gravel columns under the dam (two variants with differing diaphragm wall lengths)

a model of the water dam segment accounting for gravel columns and a drainage ditch, but without a diaphragm wall. In the case of founding on gravel columns, the base was modelled as an anisotropic medium in terms of seepage properties, macroscopically equivalent to the actual soil medium.

The numerical model utilises the finite element method. The geometry of the dam and geological substrate was defined in the GIS tools in the form of a 3D model of the terrain and geology of the substrate.

#### Mots clés

- Seepage
- 3D simulation
- anisotropy
- gravel columns

Accès libre

#### Comparison of Analysis Specifications and Practices for Diaphragm Wall Retaining System

Pages: 21 - 29

#### Résumé

Diaphragm walls are deep embedded earth retaining structures. They also act as a part of the foundation. Geotechnical codes of practice from various countries provide procedures for the analysis of deep foundations. Not many standards are available that directly regulate the analysis of diaphragm walls. This paper compares the analysis of diaphragm walls performed using the foundation codes of different countries. Codes including EN 1997-1, BS 8002, BS 8004, BS EN 1538, AASHTO LRFD Bridge Design Specifications, AS 4678, AS 5100.3, Canadian Foundation Engineering Manual, CAN/CSA S6, IS 9556 and IS 4651 are chosen for the study. Numerical studies and calculations are done using the finite element software Plaxis 2d. Comparative study is performed based on the values of displacements and the forces developed. Study also evaluates the effect of differences in partial safety factors. The outcome of research emphasises the need for development of comprehensive analysis procedures.

#### Mots clés

- Diaphragm wall
- numerical analysis
- codes
- partial factor
- total resistance factor

Accès libre

#### Pullout Capacity Of Cylindrical Block Embedded In Sand

Pages: 30 - 37

#### Résumé

Calculation of pullout capacity of anchoring concrete cylindrical block by finite element method is carried out. 3D model of the block assumes its free rotation. Alternative solutions with one and two pulling forces attached at different heights of the block are considered. Dependency of the ultimate pulling force on the points of its application, the block’s embedment depth as well as contact friction are investigated. Results of FE analysis and simple engineering estimations are compared. The maximum pullout resistance results from FE analysis when the rotation of the block is prevented.

#### Mots clés

- block anchors
- pullout capacity
- FE analysis
- plastic limit analysis

Accès libre

#### The concept of modification and analysis of the strength of steel roadway supports for coal mines in the Soma Basin in Turkey

Pages: 38 - 45

#### Résumé

The article presents a comparison of the roadway supports currently used in mines in the Soma basin in Turkey with new one proposed by Huta Łabędy and Central Mining Institute (GIG) in terms of resistance parameters and work in conditions of specific loads. The strength analysis of the frame was carried out using the finite element method, using the COSMOS/M program, based on the methodology developed and applied in GIG.

The frame models were built corresponding to their geometry and cross-sectional parameters of the sections used. Beam elements (BEAM3D) were used for building models, which were given cross-sectional parameters of the V36 section. This resulted in three frame models that were loaded in three ways (three load variants). The first option included roof load, acting on the roof bar in a uniform manner, at a length of about 3.0 m. In the second variant, the same load was adopted but the resistance of the side wall was omitted. However, in the third variant, the same roof load was assumed in addition to a side load, acting on the sliding arch, at a length of about 3.0 m, a value corresponding to half the load of the roof. As a result of the calculations carried out, the distribution of reduced stresses in the analysed frames and the maximum load values were obtained.

The proposed roadway supports retain the functionality of the previously used frames in terms of width, height, cross-sectional area of the support and the number of elements. They are characterised by the same weight and at the same time, they have up to 24% more load capacity because of the replacement of straight sections of curved side sections. This treatment was possible by forming individual elements of the arch with two bending radii. The additional load increase was obtained by using S550W steel.

#### Mots clés

- projects
- roadway suppor
- strength analysis

Accès libre

#### Powered Roof Support – Rock Strata Interactions on the Example of an Automated Coal Plough System

Pages: 46 - 55

#### Résumé

The study summarises the operating characteristics of the powered roof support (shield) used in an automated plough system. Investigated longwall support units were controlled automatically or by section engineers and positioned in the ‘saw tooth’ configuration with respect to the longwall face (automatic mode) or linear to the face. Shield pressure data have been analysed in order to identify the impacts of particular factors on the pressure increase profiles. The analysis was supported by the Statistica software to determine the statistical significance of isolated factors. Equations governing the leg pressure at the given time instant were derived and the roof stability factor ‘

#### Mots clés

- rock strata
- powered roof support
- operating characteristics
- monitoring

Accès libre

#### Concrete surface evaluation based on the reflected TLS laser beam’s intensity image classification

Pages: 56 - 64

#### Résumé

Dynamically developing terrestrial laser scanning technology (TLS)provides modern surveying tools, that is, scanning total stations and laser scanners. Owing to these instruments, periodic control surveys of concrete dams were performed as a part of geodetic monitoring yield point models characterised by quasicontinuity. Using the results of such measurements as a base, one can carry out a number of geometric analyses as well as acquire information for detailed analytical and calculative considerations.

The scanner, similar to total station, by determining distances and angles, identifies spatial coordinates (X, Y, Z) of the surveyed points. Registration of the reflected laser beam’s intensity value (Intensity) emitted by the scanner provides additional information on the surveyed object. Owing to high working speed and the large amount of the collected data, the scanners became an indispensable tool for geodesists.

The article assesses the possibility of application of terrestrial laser scanning in surveying changes in the surface of a concrete dam based on the experimental measurements. The condition of the dam’s downstream concrete wall was evaluated. The evaluation included changes in the surface’s roughness, cracks, seepage points, erosion caused by plant overgrowth and the degressive durability parameter of the used material (concrete).

The article presents an example of the application of the results of a laser scan in the assessment of the condition of a water dam’s external concrete surfaces. The results of experimental measurements were analysed – the results of a scan of the downstream concrete wall of a dam in Ecker (Germany) using two laser scanners characterised by different technical parameters, that is, laser wavelength (laser’s colour), range, definable point density, method of distance measurement – Leica C10, Z+F Imager 5006h. The measurement was carried out in the same weather conditions from the same sites of the test base.

The results of the measurements were analysed using, inter alia, statistical methods by defining template fields and supervised and unsupervised classification methods in reference to the selected fragments of the surface characterised by known concrete surface properties. Various classification algorithms were used. The obtained results make it possible to assess the suitability of the proposed methodology of evaluating the concrete surface’s condition and establish tool selection principles to match the practical application requirements.

#### Mots clés

- engineering geodesy
- Automatic Image Analysis
- control of dams
- assesment of concrete surface

Accès libre

#### Modelling and Assessment of a Single Pile Subjected to Lateral Load

Pages: 65 - 78

#### Résumé

A three-dimensional finite element technique was used to analyse single pile lateral response subjected to pure lateral load. The main objective of this study is to assess the influence of the pile slenderness ratio on the lateral behaviour of single pile. The lateral single pile response in this assessment considered both lateral pile displacement and lateral soil resistance. As a result, modified p-y curves for lateral single pile response were improved when taking into account the influence lateral load magnitudes, pile cross sectional shape and flexural rigidity of the pile. The finite element method includes linear elastic, Mohr-Coulomb and 16-nodes interface models to represent the pile behaviour, soil performance and interface element, respectively. It can be concluded that the lateral pile deformation and lateral soil resistance because of the lateral load are always influenced by lateral load intensity and soil type as well as a pile slenderness ratio (

#### Mots clés

- piles
- lateral response
- slenderness ratio
- flexural rigidity
- 3D FE analysis