Thesis ANÁLISIS DE SENSIBILIDAD DE PARÁMETROS GEOMÉTRICOS EN LA EVALUACIÓN DE ESTALLIDOS DE ROCAS EN UN TÚNEL PROFUNDO POR MEDIO DEL SOFTWARE RS3
Date
2022-06
Authors
ORELLANA RODRÍGUEZ, BRYAN DAVID
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Abstract
Debido a la intensa explotación de recursos minerales, cada año, la minería subterránea se vuelve más profunda, es por eso, que la probabilidad de un estallido de roca aumenta. Diferentes autores han estudiado este fenómeno con respecto a cómo localizarlos o cómo mitigar su ocurrencia para disminuir sus daños, sin embargo, hace falta estudiar el efecto de las características geométricas del túnel en más detalles. En este trabajo se emplea un método numérico de elementos finitos para simular, modelar y analizar mediante el software RS3 el efecto en el desencadenamiento de un estallido de roca, debido a la variación de los parámetros de estudio de un túnel (profundidad, razón de esfuerzos K, tasa de excavación, y la forma y dimensión del gálibo). Para modelar un estallido de roca se utiliza el enfoque “DISL” propuesto por Diederichs (2007, 2018) utilizando el criterio de falla generalizado no lineal de Hoek & Brown. Representa el comportamiento de fragmentación frágil modificando los parámetros máximos y residuales de la resistencia de la roca, evidenciando diferentes profundidades de falla. Los principales resultados evaluados corresponden a los mecanismos de falla y plastificación. Estos resultados permiten realizar un análisis de sensibilidad de cada parámetro geométrico en la ocurrencia de un estallido de roca. Los resultados obtenidos evidencian la importancia de la condición de esfuerzos in-situ, relacionada directamente con su propia razón de esfuerzos K, siendo este parámetro el más influyente en la generación de estallidos de roca. También se destaca la forma del gálibo, encontrándose el gálibo cuadrado con las mayores profundidades de falla y el elipsoidal con las menores. Los parámetros que siguen en cuanto a su influencia en la ocurrencia de un estallido de roca son: la tasa de excavación y las dimensiones del gálibo. Finalmente, con base en los resultados, es posible validar el uso del enfoque DISL para estimar la profundidad de falla asociada a un estallido de roca y entregar recomendaciones relacionadas al análisis de sensibilidad realizado con los parámetros de estudio en la ocurrencia de un estallido de roca.
Due to the intense exploitation of mineral resources, every year underground mining gets deeper where the probability of a rockburst increases. Different authors have studied this phenomenon with respect to how to locate them or how to minimize their occurrences to reduce their damage, however, it is necessary to study the effect of the geometric characteristics of the tunnel in more detail. In this work, a finite element numerical method is used to simulate, model and analyze, using RS3 software, the effect on the triggering of a rockburst due to the variation of the study parameters of a tunnel (depth, stress ratio, excavation rate, and the shape and dimension of the tunnel). To model this phenomenon, the "DISL" approach proposed by Diederichs (2007, 2018) is used, which uses the nonlinear generalized failure criterion of Hoek & Brown and represents the behavior of brittle fragmentation by modifying the maximum parameters and residuals of the resistance of the rock evidencing different fault depths. The main results evaluated correspond to the failure mechanisms, plastification and failure depth. These results allow performing a sensitivity analysis of each geometric parameter in the occurrence of a rockburst. The results obtained show the importance of the in-situ stress condition, directly related to its own stress ratio K, this parameter being the most prominent in the generation of rockbursts. The shape of the tunnel is also highlighted, finding the square tunnel with the greatest fault depths and the ellipsoidal with the smallest. The parameters that follow in terms of their influence on the occurrence of rockburst are the rate of excavation and the dimensions of the tunnel. Finally, based on the results, it is possible to validate the use of the DISL approach to estimate the depth of failure associated with a rockburst and provide recommendations about this phenomenon, related to the sensitivity analysis performed with the study parameters in the occurrence of rockburst.
Due to the intense exploitation of mineral resources, every year underground mining gets deeper where the probability of a rockburst increases. Different authors have studied this phenomenon with respect to how to locate them or how to minimize their occurrences to reduce their damage, however, it is necessary to study the effect of the geometric characteristics of the tunnel in more detail. In this work, a finite element numerical method is used to simulate, model and analyze, using RS3 software, the effect on the triggering of a rockburst due to the variation of the study parameters of a tunnel (depth, stress ratio, excavation rate, and the shape and dimension of the tunnel). To model this phenomenon, the "DISL" approach proposed by Diederichs (2007, 2018) is used, which uses the nonlinear generalized failure criterion of Hoek & Brown and represents the behavior of brittle fragmentation by modifying the maximum parameters and residuals of the resistance of the rock evidencing different fault depths. The main results evaluated correspond to the failure mechanisms, plastification and failure depth. These results allow performing a sensitivity analysis of each geometric parameter in the occurrence of a rockburst. The results obtained show the importance of the in-situ stress condition, directly related to its own stress ratio K, this parameter being the most prominent in the generation of rockbursts. The shape of the tunnel is also highlighted, finding the square tunnel with the greatest fault depths and the ellipsoidal with the smallest. The parameters that follow in terms of their influence on the occurrence of rockburst are the rate of excavation and the dimensions of the tunnel. Finally, based on the results, it is possible to validate the use of the DISL approach to estimate the depth of failure associated with a rockburst and provide recommendations about this phenomenon, related to the sensitivity analysis performed with the study parameters in the occurrence of rockburst.
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Keywords
EXPLOTACION MINERA , MINERIA SUBTERRANEA , EXCAVACION DE ROCAS
