Replacing RQD and discontinuity spacing with the modified blockiness index in the Rock Mass Rating system

• Autorzy: Chen Q. , Yin T. , Niu W.

Identyfikatory

DOI

10.24425/122452

Warianty tytułu

PL

Zastąpienie klasyfikacji jakości skał (RQD) i odległości pomiędzy nieciągłościami skał zmodyfikowanym współczynnikiem opisującym strukturę blokową warstw skalnych w systemie oceny stanu górotworu

• Języki publikacji: EN

Abstrakty

EN

The evaluation accuracies of rock mass structures based on the ratings of the Rock Quality Designation (RQD) and discontinuity spacing (S) in the Rock Mass Rating (RMR) system are very limited due to the inherent restrictions of RQD and S. This study presents an improvement that replaces these two parameters with the modified blockiness index (Bz) in the RMR system. Before proceeding with this replacement, it is necessary for theoretical model building to make an assumption that the discontinuity network contains three sets of mutually orthogonal disc-shaped discontinuities with the same diameter and spacing of discontinuities. Then, a total of 35 types of theoretical DFN (Discrete Fracture Network) models possessing the different structures were built based on the International Society for Rock Mechanics (ISRM) discontinuity classification (ISRM, 1978). In addition, the RQD values of each model were measured by setting the scanlines in the models, and the Bz values were computed following the modified blockiness evaluation method. Correlations between the three indices (i.e., Bz, RQD and S) were explored, and the reliability of the substitution was subsequently verified. Finally, RMR systems based on the proposed method and the standard approach were applied to real cases, and comparisons between the two methods were performed. This study reveals that RQD is well correlated with S but is difficult to relate to the discontinuity diameter (D), and Bz has a good correlation with RQD/S. Additionally, the ratings of RQD and S are always far from the actual rock mass structure, and the Bz ratings are found to give better characterizations of rock mass structures. This substitution in the RMR system was found to be acceptable and practical.

PL

Dokładność oceny struktury górotworu w oparciu o określenie jakości skał oraz odległości pomiędzy kolejnymi nieciągłościami (S) w systemie oceny stanu górotworu (RMR-Rock Mass Rating) jest mocno ograniczona z powodu ograniczeń wbudowanych w samą strukturę modelu RQD i w procedury obliczania odległości pomiędzy nieciągłościami. W niniejszej pracy zaproponowano ulepszone rozwiązanie zakładające zastąpienie powyższych dwóch parametrów przez jeden wskaźnik oceny struktury blokowej (Bz) w systemie RMR. Jednakże przed zastąpieniem wskaźników konieczne okazało się opracowanie modelu teoretycznego opartego na założeniu że sieć nieciągłości zawiera trzy zbiory wzajemnie ortogonalnych nieciągłości w kształcie dysków, mających tę samą średnicę i zlokalizowanych w równych odstępach. Następnie opracowano w sumie 35 typów teoretycznych dyskretnych modeli nieciągłości DFN (Discrete Fracture Network) o różnych strukturach w oparciu o klasyfikację nieciągłości określoną przez International Society for Rock Mechanics (ISRM, 1978). Ponadto, wartości RQD dla każdego z modeli zostały zmierzone poprzez odpowiednie ustawienie linii wybierania w modelu, zaś wartości Bz obliczono w oparciu o zmodyfikowaną metodę oceny struktury blokowej. Badano wzajemne korelacje pomiędzy trzema wskaźnikami (Bz, RQD, S), badano także wiarygodność modeli po podstawieniu. W etapie końcowym, system RMR oparty na zaproponowanej metodzie i podejściu standardowym został zastosowany do analizy rzeczywistych przypadków w celu porównania wyników uzyskanych w oparciu o powyższe dwie metody. Wyniki wskazały wysoki stopień korelacji wielkości RQD i S, choć trudno znaleźć korelacje pomiędzy RQD a średnicą nieciągłości (D). Stwierdzono także wysoki stopień korelacji pomiędzy wartościami RQD i S. Ponadto, stwierdzono że wielkości RQD i S nie opisują dokładnie rzeczywistej struktury górotworu, zaś ocena oparta na wskaźniku Bz wydaje się lepiej charakteryzować jego strukturę. Podstawienie tego parametru do systemu klasyfikacji RMR wydaje się więc akceptowalne i uzasadnione praktycznie.

Słowa kluczowe

EN

rock quality designation; modified blockiness index; discontinuity spacing; substitution; Rock Mass Rating

PL

system określenia jakości skał; odstępy pomiędzy nieciągłościami; zmodyfikowany wskaźnik opisujący strukturę blokową górotworu; zamiana współczynników; system klasyfikacji skał

• Wydawca: Instytut Mechaniki Górotworu PAN
• Czasopismo: Archives of Mining Sciences
• Rocznik: 2018
• Tom: Vol. 63, no. 2
• Strony: 353--382
• Opis fizyczny: Bibliogr. 56 poz., rys., tab., wykr.

Twórcy

autor

Chen Q.

• College of Resources, Environment and Materials, Guangxi University, Nanning, Guangxi, 530004, PR China
• State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, PR China

autor

Yin T.

• College of Resources, Environment and Materials, Guangxi University, Nanning, Guangxi, 530004, PR China
• State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, PR China

autor

Niu W.

• State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, PR China
• School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, PR China

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Uwagi

PL

Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2018)