Eva Hrubešová

Influence of local geological pattern on values of vibrations induced by road traffic

Buildings in the proximity of roads can be affected by vibrations induced by traffic. Local geological pattern is necessary to be taken into account because it has significant influence on values of vibrations and their characteristics. This paper summarizes results of experimental measurements. Four different types of buildings in different types of local geology were used for this purpose. The obtained results document that the generation of significant vibrations is mostly due to heavy vehicles. Some maximum velocity values exceed acceptable limits according to the Czech Technical Standard 73 0040 for evaluation of technical seismicity effect on buildings. Cosmetic damage, meaning the cracking of plaster, might occur due to traffic vibrations.

Analysis of Technical Seismicity in the Vicinity of Reconstructed Road

Analysis of Technical Seismicity in the Vicinity of Reconstructed Road This contribution deals with evaluation of seismic loading of structures located in the vicinity of reconstructed road where vibratory roller was used. Experimental seismological measurements were carried out in Karlova Studánka, Bruntál district. The structures in the vicinity of the reconstructed road are mostly listed and owned by local company - Státní léčebné lázně Karlova Studánka, s.p. In addition to the results of experimental measurement, the contribution also contains results of mathematical modeling. Executed analysis of data demonstrates that the vibration effect on the structures is positively influenced by use of suitable vibration technology. Hodnocení Technické Seizmicity v Okolí Rekonstruované Komunikace Příspěvek se zabývá hodnocením seizmického zatížení stavebních objektů v okolí rekonstruované komunikace při použití těžké vibrační techniky. Konkrétní řešený příklad vychází z experimentálního měření vibrací vyvolaných při rekonstrukci komunikace v obci Karlova Studánka na Bruntálsku. Většina stavebních objektů situovaných v bezprostřední blízkosti komunikace je ve vlastnictví podniku Státní léčebné lázně Karlova Studánka, s.p. a jedná se o památkově chráněné objekty. Kromě výsledků experimentálního měření in situ jsou v příspěvku představeny také výsledky numerického modelování dané situace. Analýza dat prokázala, že použitím vhodné vibrační technologie lze dosáhnout příznivých výsledků z pohledu vlivu na objekty.

Assessment of Fiber Reinforced Concrete Slab and Subsoil Interaction - Experiment

The paper is focused on the interaction of the fibre reinforced concrete slab and the subsoil using both the results of experimental measurements on the experimental stand. Performed experimental measurements include monitoring of the concentrically loaded concrete slab with the dimensions of 2 m x 2 m and thickness of 0.15 m. This slab is in the interaction with subsoil of sandy clay character. The experimental load is applied in sequential steps by using a hydraulic press. During the tests the strain gauges and hydrostatic levelling method were used for the monitoring of the settlements of the slab. The contact stresses and the stresses corresponding to a certain depth below the slab were monitored by using a flat pressure cells. In the conclusion of this paper there are formulated the basic aspects of concrete slab-subsoil interaction, the results of various performed experimental measurements and the comparison of stress below the surface resulted from interaction of soil and slab of different degree of reinforcement.

Assessment of tunnel’s face support pressure

The evaluation of support pressure ensuring tunnels face stability during excavation using tunnel boring machines is one of the fundamental problems in tunnelling. This paper presents various approaches to this problem. The analytical models, based either on the principle of limit equilibrium or the limiting analysis (low boundary or upper boundary limiting methods), requires considerable simplification (circular tunnel, homogeneous rock mass etc.). But, on the other hand they are less time-consuming in comparison with the numerical models based on the finite element method. This paper describes the comparison of results of minimum face pressure obtained on the basis of different calculation methods with respect to the specific geometrical and material characteristics of the problem. Geotechnical software Midas GTS NX (based on finite element method) was used for presented numerical analysis. The paper also provides a comparison of modelling results with the results of the face pressure corresponding to the real excavation of the tunnel.

Static design of steel-concrete lining for traffic tunnels

Article summarizes the results of research focused on the structural design of traffic tunnel linings that have been achieved in the framework of a research project TE01020168 that supports The Technology Agency of Czech Republic. This research aim is to find and develop a process for design structure parameters of tunnel linings. These are now mostly build up by a shotcrete technology. The shotcrete is commonly endorsed either with steel girders or steel fibres. Since the installation a lining structure is loaded while strength and deformational parameters of shotcrete start to rise till the setting time elapses. Thats reason why conventional approaches of reinforced concrete are not suitable. As well as there are other circumstances to step in shown in this article. Problem is solved by 3D analysis using numerical model that takes into account all the significant features of a tunnel lining construction process inclusive the interaction between lining structure with rock massive. Analysis output is a view into development of stress-strain state in respective construction parts of tunnel lining the whole structure around, including impact on stability of rock massive. The proposed method comprises all features involved in tunnel fabrication including geotechnics and construction technologies.

Numerical Modelling for Twin Horizontal Circle Tunnels Under Static and Dynamic Loads

According to recent studies and observed failures of underground structures, many researchers have addressed the design and construction of tunnel lining against static/dynamic loads and earthquake vibration to get the safety of these structures. Therefore this paper includes the study of the behavior of tunnel lining due to static and dynamic loads. Inner diameter of tunnel is D m. Concrete lining of thickness 0.3 m. The depth of the tunnel centre line from the ground level is 10 D below the surface of the ground, the twin tunnel centre are 3D. After tunnel model is created in the software MIDAS GTS NX, the model is run to analyze the tunnel stability and deformation in static and dynamic conditions by calculating the value of each mesh node based on 3D finite element method and were undertaken to investigate the seismic tunnel response conditions to compare the results in the displacement, stresses, forces and bending moments acting on the tunnel lining. Due to the application of the static load the stress–strain state around the tunnel periphery is changed, the primary stress state is disrupted and the potential of instability increases, otherwise the result shows that the applied dynamic stress is not negligible for underground structure, but it is less dangerous in comparison with the others.

Uncertainties of Shear Strength Parameters of Soil Reinforced by Plastic Waste

In geotechnical practice we often meet the case when soils need to be improved. Various methods for the ground improvement are used in the geotechnical practise. One from methods of soils improvements can use also fiber-shaped waste materials. Such as polyethylene terephthalate (PET) plastic bottles are profusely and widely produced, yet used little for engineering purpose, and the overwhelming majority of them are placed in storage or disposal sites.One form expected improvements is increase of soil shear strength parameters which can be obtained by various methods, including laboratory tests. Determination of soil shear strength parameters by DST is still extensively used. In this paper we will deal with soil shear strength parameters of soil without and with plastic chips and their uncertainty. Uncertainties of shear strength parameters of soil without or with plastic chips are not negligible.

NUMERICAL MODEL OF THE DYNAMIC LOAD RESPONSE IN THE REAL ROCK MASS USING LATIN HYPERCUBE SAMPLING METHOD

Abstract This paper follows on previous paper “numerical model of the dynamic load response in the soil using Latin hypercube sampling method”. In this paper the Latin Hypercube Sampling method (LHS) is used in order to evaluate the values of input parameters of real rock environment. The resulting values of the models were compared with the experimental in-site measurements. Twenty input values were generated for each input parameter. The peak oscillation velocities were calculated for 15 different surface points. The results were statistically analyzed in each distance (the basic statistical characteristics were evaluated). Based on this stochastic analysis the attenuation curve of the vibration velocity with the certain level of probability were determined.

Deformation Characteristics of Shot Concrete Lining and Steel Lattice Beams

Deformation Characteristics of Shot Concrete Lining and Steel Lattice Beams Steel-concrete tunnel lining is the only type of stabilizing structure statically active in phase of its construction, i.e. immediately after execution of excavating. This fact predestinates it for stabilization of excavation in interaction with solid rock mass. Deformation characteristic of the shot concrete lining is determined by variable stiffness of the lining cross-section during the construction and shortly after its completion, and it is subjected to the advancement upon construction of the lining. Variable stiffness of the lining structure enables controlled release of stress state of the solid rock mass after execution of excavation. The present contribution analyzes activity of the shot concrete tunnel lining and steel lattice beams. Deformation characteristics are determined based on mutual interaction of the lining and solid rock mass during individual constructional stages of the lining determined by geometrical parameters of the lining cross-section and state of individual shot concrete layers hardening. Deformační Charakteristika Ostění Ze Stříkaného Betonu a OcelovýCH Příhradových Nosníků Ocelobetonové tunelové ostění je jediným typem stabilizační konstrukce, která je staticky činná již ve fázi její výstavby, která následuje bezprostředně po provedení výrubu. Tato okolnost ji předurčuje k stabilizaci výrubu v součinnosti s horninovým masivem. Deformační charakteristiku ocelobetonového ostění určuje proměnlivá tuhost průřezu ostění během výstavby a krátce po jeho dokončení a je dána procesem výstavby ostění. Proměnlivá tuhost konstrukce ostění umožňuje řízené uvolnění napěťového stavu horninového masivu po provedení výrubu. Předložený článek analyzuje činnost tunelového ostění ze stříkaného betonu a ocelových příhradových nosníků. Deformační charakteristika je stanovena na základě vzájemné interakce mezi ostěním a horninovým prostředím v průběhu konstrukčních etap budování ostění, které jsou určeny geometrickými parametry průřezu ostění a stavem tvrdnutí jednotlivých vrstev stříkaného betonu.

Parametric Study on the Effects of Soil to Oscillation Velocity / Parametrická Studie Vlivu Typu Zeminy Na Amplitudu Rychlosti Kmitání

Abstract The paper focuses on the possibility of evaluating the influence of character of the soil to oscillations velocity induced dynamic loads. Mathematical modeling is used to solve the parametric study. Models are created in software Plaxis 2d based on finite element method. Dynamic load is based on experimental measurements on the stand in the area of the Faculty of Civil Engineering, VSB-TUO. Soil properties are determined from the normative indicative characteristics. Abstrakt Příspěvek je zaměřen na možnost posouzení vlivu charakteru zemin na amplitudu rychlosti kmitání vyvolanou dynamickým zatížení. Pro řešení parametrické studie je využito matematického modelování ve výpočetním programu Plaxis 2D založeného na metodě konečných prvků. Dynamické zatížení vychází v příspěvku z experimentálního měření provedeného na standu v areálu Fakulty stavební, VŠB-TUO. Vlastnosti zemin vycházejí ze směrných normových charakteristik.