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Rock mass classification in highway tunnel engineering during exploration phase and case study

Yanqiang Du, Bing Xie

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

141--153

EN

It is the foundation of tunnel engineering to classify the rock mass surrounding tunnels. However, it is not easy to precisely determine the class of rock mass in practice as sufficient geological exploration need to be completed before rock mass classification, and there exists some disputes referring to the rationalization of dozens of methods for rock mass classification through the world. The principles and procedures of the basic quality method, which are widely used in China, are presented in this paper, and the application process of the basic quality method is showed with a project case of Zhongnanshan highway tunnel which has operated in safety for nearly a decade. Then, both the advantages and disadvantages of the basic quality method are analyzed in terms of practical engineering applications. In consideration of the defects of the basic quality method, the concept of the subclassing of surrounding rock in grade III-V is developed in the end and the criterion is given to determine the subclass of rock mass. This study is aimed at providing some useful ideas and a reference for rock classification in highway tunnel engineering.

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Investigating the effectiveness of a ground support system implemented on Block A: a case study of Southern Africa metalliferous mine

Manyelo Kamogelo, Kolapo Peter

Journal of Sustainable Mining

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2022

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Vol. 21, iss. 1

15--26

EN

This study aims to investigate the effectiveness of the ground support systems that are planned to be implemented on Block A, which will be excavated through the Marikana fault zone. The block of ground being prepared for mining has been physically affected by the presence of the Marikana fault and is therefore geomechanically and geotechnically weaker than the normal stoping conditions on the rest of the shaft. Joint mapping conducted in Block A raiselines indicated that there is a high concentration of shallow dipping joints which are dipping in opposite directions. Such conditions present special challenges in the planned excavations because they can lead to sudden and uncontrolled collapses unless appropriate action is taken to mitigate such instances. The orientation of joint sets aid the formation of keyblocks, which can collapse provided their weight exceeds the support load bearing capacity or if they are located in between support units. Therefore, stoping in the Marikana fault zone requires a more intensive support with a higher than normal support resistance. The existing ground control strategies, the processes, tools, techniques, and methods that are currently being used for support design were investigated and incorporated into the new system where applicable.

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Możliwości zastosowania klasyfikacji jakości górotworu RMR w warunkach polskiego górnictwa rud miedzi

Janik D., Juszyński D., Terpak D.

Rudy i Metale Nieżelazne Recykling

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2017

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R. 62, nr 5

3--9

PL

Jednym z podstawowych elementów planowania eksploatacji jest rozpoznanie górotworu. W artykule przedstawiono wybrane klasyfikacje jakości masywu skalnego do prowadzenia w nim robót górniczych. Klasyfikacje zostały przeanalizowane w aspekcie możliwości ich stosowania w warunkach IGOM.

EN

One of the basic elements of planning exploitation is the recognition of the rock quality The article presents selected classifications of rock mass quality for mining works. Classifications have been analyzed in terms of their applicability in Polish copper ore mining.

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Morfometryczna metoda oceny jakości górotworu na potrzeby doboru obudowy kotwiowej w kopalni rud cynku i ołowiu "Pomorzany"

Korzeniowski W.

Górnictwo i Geoinżynieria

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2007

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R. 31, z. 3/1

257-267

PL

Podstawową obudową wyrobisk eksploatacyjnych w polskich kopalniach rud cynku i ołowiu jest obudowa kotwiowa. Na podstawie wieloletnich obserwacji zachowania się wyrobisk, badań jakości górotworu oraz skuteczności kotwienia w zróżnicowanych warunkach geotechnicznych zaproponowano wprowadzenie uzupełniającego kryterium do klasyfikacji stropu pod kątem doboru kotwi. Zastosowanie morfometrycznej metody opisu odsłoniętego stropu i ociosów wyrobisk pozwoliło na wyodrębnienie czterech typów kategorii powierzchni, wyraźnie związanych ze skutecznością zastosowanej obudowy i statecznością wyrobisk. Wprowadzenie dodatkowego parametru do aktualnie stosowanej metodyki ma na celu przede wszystkim zminimalizowanie niedokładności szacowania jakości rdzenia wiertniczego.

EN

The basic support method of exploitation workings in Polish lead and zinc mines is the bolting technique. Based on many years of observations of behaviour of underground excavations, investigations on strata quality and bolting effectiveness under diversified geotechnical conditions, a supplementary criterion for roof classification and bolt matching has been suggested. Application of the morphometric method for description of roofs and wall-sides in the excavations allowed the four characteristic surface categories to be specified that are in clear relation with bolting effectiveness and the excavation stability. The goal of the introduction of extra parameters into the obligatory method is first of all, to minimize the error in RQD estimation.