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Abstract: A standard dynamic loading test of the pile was performed on the highway section Slivnica - Hajdina near Maribor, Slovenia. Parallel to standard testing procedures the new monitoring technology based on specially developed strain sensors installed inside the pile body along the pile axis was introduced. On the basis of the measured results the normal strains along the pile axis were measured. Taking into consideration the elastic modulus of the concrete the normal stresses in the axial direction of the pile were also calculated and afterwards the shear stresses along the pile shaft have been estimated as well as the normal stresses below the pile toe. The estimation was made by considering a constant value for the pile diameter. The measured results were also compared with the computer simulation of the pile and the soil behaviour during all the successive test phases. The strain measurements inside the pile body during the standard dynamic loading test in present case did not have the purpose of developing an alternative method of pile loading tests. The presented monitoring technology proved itself as a very accurate and consistent. It gave in the first place the possibility of a closer look at the strains and stresses of the most unapproachable parts of different types of concrete structure elements especially piles and other types of deep foundations.
Keywords: piles, deep foundations, dynamic loading test, strain measurement technologies, elasto-plastic modelling, finite-element method
Published in DKUM: 06.06.2018; Views: 1395; Downloads: 175
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Abstract: This paper deals with the sedimentation of suspended load in the reservoirs. As an example the reservoir of the hydroelectric power plant Boštanj on the Sava River is shown. The objective of the described studies was to determine the quantity and type of deposited material in the reservoir during the selected time period. For this purpose, the mineral and chemical composition, and the concentration and the particle size of the suspended load at the intake of the water into the reservoir and at its outflow were examined. In order to determine the concentration of the suspended load, 24 water samples from the area of the intake and outflow from the reservoir were taken. At the same time the discharge of the Sava River was measured. Solid particles were removed from the water with the help of sedimentation and in the final stage of water evaporation. The results of the studies showed that the concentration of the suspended material was changing in relation to the location and the flow rate of the water. This ratio can be described with an exponential function. In suspended load composition carbonates, muscovite/illite and quartz dominate; however, chlorite was also found, as well as small quantities of plagioclase and organic detritus. With regard to the size of the particles the examined samples are classified as silt. It was determined that the concentration of the suspended load, at the same flow rate of water, at the intake into the reservoir is larger than at the outflow. The difference is represented by the material that was sedimented in the reservoir due to the decreased speed of the water as a result of the river's impoundment. A comparison of the composition of the samples from both collection sites showed that at the outflow site of the water from the reservoir there is a somewhat smaller share of carbonate grains and heavy minerals than at the intake site, and a higher content of organic detritus and clay particles can also be observed. Considering the actual discharge of water in the period between July 2006 and July 2007 and the examined ratio between the flow rate of the water and the quantity of suspended and deposited material, the total quantity of sedimented material in this period was estimated.
Keywords: suspended load, sedimentation, sediment transport, water storage reservoir
Published in DKUM: 05.06.2018; Views: 2091; Downloads: 83
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Abstract: The type of a retaining structure as well as the structure configuration mainly depends on geological conditions. If geological, urban and other data allow an alternative, the costs should also be considered as an important factor. In geotechnical practise, pile walls are especially used in excavations, in the erection of traffic facilities and in the sanitation of landslides. This paper is aimed at presenting economical differences between cantilever and anchoring pile walls and the impact of different parameters on costs. The optimization method, which uses mathematical programming, gives an optimal solution to geometry, self-manufacturing costs, and other characteristics of the structure in a uniform optimization process. This paper presents the optimization process using the nonlinear programming (NLP) approach for the anchored pile wall. The application presented only serves to confirm the effectiveness of the proposed optimization method. Therefore, the retaining structure is situated in homogeneous non-cohesive soil at three different soil friction angles of 35°, 30° and 25°. The generalized analytical method, the USA method, which was first introduced by Bowles [3], isused in the application. The analysis of the results shows the impact of parameters, the main controlling factors, configuration geometry and savings. The optimal results allowed from 18 up to 47 per cent savings compared to the cantilever pile wall depending on ground and structure input data and the excavation depth.
Keywords: civil engineering, optimum design, retaining structures, USA analytical method, nonlinear programming
Published in DKUM: 16.05.2018; Views: 1419; Downloads: 71
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Abstract: Diplomsko delo predstavlja splošen opis voziščne konstrukcije, sledi dimenzioniranje voziščne konstrukcije z uporabo tehničnih specifikacij za javne ceste ter izračun napetostno deformacijskega stanja v nevezani nosilni plasti. Izračun napetosti in deformacij izvedemo po metodi končnih elementov z uporabo geotehničnega programa Plaxis. Dobljene rezultate analiziramo in jih primerjamo z izmerjenimi rezultati na terenu. V drugem delu diplomske naloge so na praktičnem primeru uporabe murskih prodov prikazani rezultati laboratorijskih preiskav različnih mešanic murskega proda in s pomočjo matematičnih metod izračunane napetosti in deformacije. Rezultati pokažejo, da se z uporabo drobljenih prodov trajne deformacije v nevezani nosilni plasti bistveno zmanjšajo.
Keywords: voziščna konstrukcija, nevezana nosilna plast, prometna obremenitev, program Plaxis, dinamična obremenitev, tehnične specifikacije, trajne deformacije, napetostno stanje, metoda končnih elementov
Published in DKUM: 20.04.2011; Views: 3778; Downloads: 635
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Keywords: portali, predori, geotehnične razmere, geološke razmere, stabilnost pobočja, stabilnostne analize, metoda končnih elementov
Published in DKUM: 26.07.2007; Views: 2609; Downloads: 0