Browsing by Author "Astudillo Matute, Washington Santiago"

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Análisis de transporte de carga de lecho para partículas gruesas
(2017) Astudillo Matute, Washington Santiago; Padilla Guarnizo, Carlos Ramiro; Carrillo Serrano, Verónica Margarita
The development of an equation that allows the accurate determination of bed load transport rates for rivers with rugged topography and presence of coarse sediment in its bed is necessary for the better development of design parameters. Current equations provided and developed in multiple literature sources overestimate the range of bed load transport when equations are applied to specific conditions that differ from those used in the originals studies, such as laboratory channels, low slopes, limited flow ranges, etc. This all generates unreliable results. For this reason, this current study is aimed towards determining transport capacity of shallow flows in high slope channels and different particle sizes through the development of an equation for the processes related to the bottom transport of mountain rivers. Laboratory simulations and a regression analysis of the data were conducted. Additionally, a comparative study of the results obtained in the laboratory with the potential theoretical rates that projected several bed load transport equations available in the literature were carried out. The study established that the developed equation, determined experimentally, keeps a high similarity to the values reported by the empirical equations of Yalin (1963) and Parker (1979) with a similarity of 97% and 92% respectively. Although the relationship determined by the development of this new equation represents an improved alternative for determining bed load transport rates in mountain beds with the presence of coarse sediment, further studies using of more real conditions is still necessary. However, the empirical model of the present study can constitute a solid starting point to improve the accuracy in estimation of transport rates.
Validation of an experimental procedure to determine bedload transport rates in steep channels with coarse sediment
(2021) Padilla Guarnizo, Carlos Ramiro; Cisneros Espinoza, Felipe Eduardo ; Carrillo Serrano, Verónica Margarita; Petrie, John E.; Timbe Castro, Luis Manuel; Pacheco Tobar, Esteban Alonso; Astudillo Matute, Washington Santiago
The current study presents an experimental procedure used to determine bedload sediment transport rates in channels with high gradients and coarse sediment. With the aim to validate the procedure for further investigations, laboratory experiments were performed to calculate bedload transport rates. The experiments were performed in a laboratory tilting flume with slopes ranging from 3% to 5%. The sediment particles were uniform in shape (spheres). The experiments were divided into four cases based on sediment size. Three cases of uniform sizes of 10 mm, 15 mm and 25 mm and a case with a grain size distribution formed with the uniform particle sizes were considered. From the experimental results a mathematical bedload transport model was obtained through multiple linear regression. The experimental model was compared with equations presented in the literature obtained for gravel bed rivers. The experimental results agree with some of the models presented in the literature. The closest agreement was seen with models developed for steep slopes especially for the highest slopes considered in the present study. Therefore, it can be concluded that the methodology used can be replicated for the study of bedload transport rates of channels with high gradients and coarse sediment particles to study more general cases of this process such as sediments with non-uniform shapes and sizes. However, a simplified model is proposed to estimate bedload transport rates for slopes up to 5%.