Encontrados 40 documentos, a visualizar página 1 de 4
Evaluation of code formulations for NSM CFRP bond strength of RC elements
Coelho, Mário R. F.; Sena-Cruz, José; Dias, Salvador J. E.; Miranda, Tiago F. S.This paper presents an analytical analysis which intends to verify the accuracy of existing code formulations for predicting the pullout strength of NSM CFRP systems applied to concrete. A database with a limited set of parameters was gathered and two code formulations were tested on it. Then, a new approach was tested. This uses Data Mining algorithms to develop models to predict the pullout strength based on ...
Back analysis of geomechanical parameters in underground works using an evoluti...
Moreira, Nuno Ricardo Vilaça; Miranda, Tiago F. S.; Pinheiro, Marisa da Mota; Fernandes, Pedro Miguel Gomes; Dias, Daniel; Costa, L.; Sena-Cruz, JoséThe purpose of this work is to evaluate the performance of an optimization algorithm from the field of evolutionary computation, namely an Evolution Strategy, in back analysis of geomechanical parameters in underground structures. This analysis was carried out through a parametric study of a synthetic case of a tunnel construction. Different combinations of parameters and measurements were carried out to test t...
Application of Data Mining techniques for the development of new rock mechanics...
Miranda, Tiago F. S.; Sousa, Luís Ribeiro e; Roggenthen, W.; Sousa, R. L.Data Mining (DM) techniques have been successfully used in many fields and more recently also in geotechnics with good results in different applications. They are adequate as an advanced technique for analysing large and complex databases that can be built with geotechnical information within the framework of an overall process of Knowledge Discovery in Databases (KDD). A KDD process is carried out in the conte...
Prediction of hard rock TBM penetration rate based on Data Mining techniques
Martins, Francisco F.; Miranda, Tiago F. S.The aim of this work is to use Data Mining tools to develop models for the prediction of hard rock tunnel boring machine (TBM) penetration rate (ROP). A database published by Yagiz (2008) was used to develop these models. The parameters of the database were the uniaxial compressive strength (UCS), an index used to quantify the brittleness and toughness and denominated peak slope index (PSI), the distance betwe...
Experimental investigation on the repair of rammed earth by means of injection ...
Silva, Rui André Martins da; Oliveira, Daniel V.; Schueremans, Luc; Lourenço, Paulo B.; Miranda, Tiago F. S.This paper assesses the adhesion capacity of unmodified mud grouts used to repair structural cracks on medium and large scale rammed earth specimens. Beam and wallet-specimens were manufactured using a soil from Alentejo (Portugal), whose particle size distribution had to be first corrected due to its high clay content. An “artificial” (composed by kaolin and limestone powder) and a “natural” (composed by sieve...
Rheological properties of alkaline activated fly ash used in jet grouting appli...
Cristelo, Nuno; Soares, Edgar; Rosa, Ivo; Miranda, Tiago F. S.; Oliveira, Daniel V.; Silva, Rui André Martins da; Chaves, Ana Margarida Vaz AlvesThe application of alkaline activated fly ash to soil stabilisation has been recently studied, and although the structural behaviour was adequate, some concerns were raised regarding its apparent viscosity, which proved to be an important issue in jet grouting applications. Therefore, this paper deals with the experimental study of rheology of alkaline activated fly ash-based grouts, namely with: setting time o...
Rammed earth construction with granitic residual soils : the case study of nort...
Silva, Rui André Martins da; Oliveira, Daniel V.; Miranda, Tiago F. S.; Cristelo, Nuno; Escobar, Maria C.; Soares, EdgarBuilding in unstabilised rammed earth results in low environmental impact. However, northern Portugal has not historical tradition with this technique, and thus the suitability of the local granitic residual soils is unknown. This paper presents an experimental investigation, where this possibility is assessed. The results showed that these soils are unsuitable, and that rammed earth construction is only feasib...
Estimation of the rock deformation modulus and RMR based on data mining techniques
Martins, Francisco F.; Miranda, Tiago F. S.In this work Data Mining tools are used to develop new and innovative models for the estimation of the rock deformation modulus and the Rock Mass Rating (RMR). A database published by Chun et al. (2008) was used to develop these models. The parameters of the database were the depth, the weightings of the RMR system related to the uniaxial compressive strength (UCS), the rock quality designation (RQD), the joint...
Soil stabilisation using alkaline activation of fly ash for self-compacting ram...
Cristelo, Nuno; Glendinning, Stephanie; Miranda, Tiago F. S.; Oliveira, Daniel V.; Silva, Rui André Martins daThis paper studies the effectiveness of alkaline activation of low-calcium fly ash on the improvement of residual granitic soils to be used on rammed-earth construction. Different liquid:solid ratios, alkali concentrations and Na2O : ash ratios were tested. Effect of calcium hidroxide, sodium chloride and concrete superplasticiser is also reported. Compressive strength up to 7 days at 60ºC was determined. Resul...
Prediction of rockburst based on experimental systems and artificial intelligen...
He Manchao; Jia Xuena; Peixoto, Ana; Sousa, L. R.; Sousa, Rita Leal; Miranda, Tiago F. S.Rockburst is characterized by a violent explosion of a certain block causing a sudden rupture in the rock and is quite common in deep tunnels. It is critical to understand the phenomenon of rockburst, focusing on the patterns of occurrence so these events can be avoided andor managed saving costs and possibly lives. The failure mechanism of rockburst needs to be better understood. Laboratory experiments are on...
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