scholarly journals Characteristics Analysis of Generalized Rock Quality Designation (RQD) Based on Degree of Joint Development

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lin Jun ◽  
Sha Peng ◽  
Gao Shuyu ◽  
Ni Jiji
Keyword(s):  
Rock Mass ◽  
Scale Effect ◽  
Great Influence ◽  
Optimal Threshold ◽  
Open Pit ◽  
Rock Quality Designation ◽  
Network Modelling ◽  
Fracture Spacing ◽  
Joint Development ◽  
Rock Quality

Rock quality designation (RQD) is widely adopted as a fundamental tool in characterizing rock masses since it was devised in 1964. Since the conventional RQD calculation is limited due to its dependence on the selected threshold, previous research introduced generalized RQD to adequately reflect the anisotropy and scale effect of RQD. However, the influence of the joint development inside rock mass on generalized RQD remains unclear. The objective of this work is to investigate characteristics of the generalized RQD in view of different development degrees of discontinuities in rock mass, including spacing (density) and trace length. Three-dimensional fracture network modelling is employed to simulate the actual rock mass of open-pit iron mine in China. Virtual scanlines are set to obtain RQD values in different directions. The results primarily show that the generalized RQD should be introduced to calculate the RQD with different thresholds to fully reflect the anisotropy of rock mass. The optimal threshold can be obtained based on an anisotropic coefficient, which is defined by (RQDmax-RQDmin). It is also indicated that the fracture spacing has a great influence on both the anisotropy of RQD and the selection of the optimal threshold. The optimal threshold of the generalized RQD increases with the increase in the fracture spacing. In addition, the scale effect of RQD in different models is discussed by changing the length of the scanlines. The longer the scanlines we set, the more stable RQD value can be obtained in the model. It is recommended to fit much longer scanline to get realistic RQD in heavily fractured rock mass.

scholarly journals Selection of Optimal Threshold of Generalised Rock Quality Designation Based on Modified Blockiness Index

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Qingfa Chen ◽  
Tingchang Yin ◽  
Hangyu Jia
Keyword(s):  
Rock Mass ◽  
Three Dimensional ◽  
Critical Index ◽  
Network Models ◽  
Optimal Threshold ◽  
Rock Quality Designation ◽  
Actual Case ◽  
Rock Quality ◽  
Anisotropy Index

Rock quality designation (RQD) is a critical index for quantifying the degree of rock mass jointing; it is widely used for evaluating the qualities and stabilities of engineering rock masses. However, the use of traditional RQD may yield inaccurate assessments because only core pieces longer than 100 mm are counted. To enhance the utility of RQD, generalised RQD was introduced. Based on the modified blockiness index (MBi), the determination of the optimal threshold of generalised RQD was performed. In this work, 35 types of hypothetical three-dimensional joint network models were constructed, and their generalised RQD values (with different thresholds) and MBi values were measured. The correlation between the standard ratings of MBi and RQD was assessed; based on this correlation, the theoretical RQD values of the 35 models were derived. The reasonable thresholds of the generalised RQD were determined according to the theoretical RQD values, and the optimal threshold of generalised RQD was obtained using the variation coefficient and anisotropy index of the jointing degree. The discrepancy between the results produced using traditional and generalised RQDs was discussed. Finally, an actual case study was conducted, and the results indicate that the generalised RQD associated with the optimal threshold determined in this study can properly quantify the degree of jointing of a given rock mass.

scholarly journals Analisis Karakteristik Massa Batuan di Sektor Lemajung, Kalan, Kalimantan Barat

EKSPLORIUM ◽  
2015 ◽  
Vol 36 (1) ◽  
pp. 17 ◽  
Author(s):  
Heri Syaeful ◽  
Dhatu Kamajati
Keyword(s):  
Compressive Strength ◽  
Rock Mass ◽  
Uniaxial Compressive Strength ◽  
Open Pit ◽  
Rock Mechanic ◽  
Rock Mass Rating ◽  
Class Iii ◽  
Rock Quality Designation ◽  
Joint Spacing ◽  
Rock Quality

Karakterisasi massa batuan diperlukan dalam suatu rancangan bukaan batuan, dimana perhitungan sifat-sifat teknis dari massa batuan menjadi hal yang penting untuk diperhatikan. Sektor Lemajung merupakan salah satu area prospek untuk penambangan uranium di Kalan, Kalimantan Barat. Tujuan penelitian adalah mendapatkan data karakteristik massa batuan yang merupakan data dasar bagi perencanaan pengembangan teknik penambangan cebakan bahan galian. Metodologi yang digunakan adalah dengan pengambilan contoh batuan untuk analisis laboratorium mekanika batuan, pengamatan rekahan, dan pengamatan kondisi airtanah. Parameter batuan yang dianalisis meliputi uniaxial compressive strength (UCS), rock quality designation (RQD), jarak rekahan, kondisi rekahan, dan airtanah. Hasil analisis menyimpulkan bahwa metalanau sebagai litologi yang mengandung uranium di Sektor Lemajung mempunyai nilai rock mass rating (RMR) sebesar 56 atau kelas massa batuan III: fair rock pada kedalaman sekitar 60 m, dan pada kedalaman 280 m nilai RMR mencapai 82 atau kelas massa batuan I: very good rock. Data nilai RMR tersebut selanjutnya dapat digunakan dalam analisis pembuatan terowongan pada model tambang bawah tanah atau analisis kestabilan lereng pada model tambang terbuka. Rock mass characterization is required in design of rock opening, which calculation of engineering characters of rock mass become one important parameter toconsider. Lemajung sector is one of prospect area for uranium mining in Kalan, West Kalimantan. Purpose of research is to acquire rock mass characteristicsas basic data for planning the development of mining technique of ore deposit. Methodology applied is rock sampling for rock mechanic laboratory analysis, observation of joints, and observation of groundwater condition. Rock parameters analyzed includes uniaxial compressive strength (UCS), rock quality designation (RQD), joint spacing, joint condition, and groundwater. Analysis concluded that metasiltstonewhich is lithology contained uranium in Lemajung Sector has rock mass rating (RMR) value of 56 or rock mass class III: fair rock in the depth of around 60 m, and in the depth of 280 m RMR value reach 82 or rock mass class I: very good rock. RMR value data furthermore could be used for analysis of tunneling in the model of underground mine or slope stability analysis in the model of open pit mine.

scholarly journals Engineering geological zoning of the Scorillo Dam site, Romania

2000 ◽  
Vol 22 ◽  
Author(s):  
Cristian Marunteanu ◽  
Ion Durdun
Keyword(s):  
Rock Mass ◽  
Modulus Of Elasticity ◽  
Grout Curtain ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
Rock Mass Quality ◽  
Engineering Geological Zoning ◽  
Dam Site

A model of engineering geological classification and zoning of the Scorillo Dam site in Romania is proposed to optimise the design of the dam and of the grout curtain. The rock mass was classified into four categories: from 1 (good) to 4 (very poor), according to the rock mass quality (RMQ) at the dam site. Parameters available and used to determine the RMQ were lithology, degree of weathering and fragmentation, rock quality designation (RQD), and modulus of elasticity (E). Based on the study, a new design of the dam, its slopes, and the grout curtain was carried out.

scholarly journals Correlation of P-wave Velocity with Rock Quality Designation (RQD) in Volcanic Rocks

2019 ◽  
Vol 3 (2) ◽  
pp. 11
Author(s):  
Ainul Fatayaatis Salaamah ◽  
Teuku Faisal Fathani ◽  
Wahyu Wilopo
Keyword(s):  
Rock Mass ◽  
Wave Velocity ◽  
Volcanic Rocks ◽  
Rock Mass Classification ◽  
Classification Systems ◽  
P Wave ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
P Wave Velocity ◽  
Mass Classification

One important part of rock mass investigation is the geomechanical assessment in terms of rock mass classification systems. Rock mass classification is one of themost efficient methods in rock mechanics to provide a basic understanding of rock masscharacterization. Rock mass properties can be determined by a seismic refraction surveyas an indirect geophysical assessment. In this study, the P-wave velocity from seismicrefraction was compared with the Rock Quality Designation (RQD) from the boreholes.The empirical correlation between the RQD and the P-wave velocity was found by usingthe linear regression analysis. The RQD value estimated from the P-wave velocity can beapplied for tropical environment study with geological conditions of volcanic rocks. This study helps to estimate and predict the subsurface rock quality, to reduce investigation costs, and to improve understanding of subsurface rock quality.

Анализ инженерных свойств горных пород участка плотины Шах-и-Арус, Кабул, Афгани

2020 ◽  
Vol 5 (1) ◽  
pp. 35-48
Author(s):  
Абдулхалим Зарьяб ◽  
◽  
Мохаммад Ибрагим Наджаф ◽  
Мохаммад Зия Джамал
Keyword(s):  
Rock Mass ◽  
Rock Mass Rating ◽  
Rock Quality Designation ◽  
Rock Quality

В настоящее время на реке Шакардара примерно в 22 км к северо-западу от г. Кабул, Афганистан, ведется строительство плотины Шах-и-Арус. Ее высота и длина составляют 77,5 м и 303 м, соответственно, а объем водохранилища оценивается примерно в 9,38 млн м 3 . Данное многоцелевое сооружение возводится из роликового уплотненного бетона (RCC) и предназначено для хранения оросительной воды, сдерживания наводнений и выработки электроэнергии. Плотина располагается в тектонически активной зоне, чем обусловливается значительное воздействие на нее тектонических процессов. В настоящей статье представлены результаты сопоставления показателей нарушенности горных пород (Rock Quality Designation, RQD) и параметров Люжона, основанных на обзоре и анализе материалов первоначальных инженерно-геологических изысканий и дополнительных полевых наблюдений. Результаты значений Люжона и показателей RQD прошли статистически-графическую оценку, и далее данные полученных графиков были сопоставлены со всеми другими естественными условиями зоны строительства плотины. Полученные результаты указывают на то, что комплекс природных условий в определенной степени характеризуется взаимосвязью между значениями Люжона и параметрами RQD. Кроме этого, массив горных пород основания плотины был охарактеризован в соответствии с классификацией скальной породы RMR (Rock Mass Rating).

Application of alternative methods for determination of rock quality designation (RQD) index: a case study from the Rožná I uranium mine, Strážek Moldanubicum, Bohemian Massif, Czech Republic

2015 ◽  
Vol 52 (10) ◽  
pp. 1466-1476 ◽  
Author(s):  
M. Vavro ◽  
K. Souček ◽  
L. Staš ◽  
P. Waclawik ◽  
L. Vavro ◽  
...  
Keyword(s):  
Rock Mass ◽  
Alternative Methods ◽  
Uranium Mine ◽  
Drill Core ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
Core Section ◽  
Drilling Technology ◽  
Rock Mass Failure

A comparison of rock quality designation (RQD) parameters obtained by drill core analysis and the RQD determined using alternative methods is presented using metamorphic rocks such as migmatized gneisses, migmatites, and amphibolites. Methods of borehole–wall imaging using high-resolution acoustic logging, optical televiewer, and simple video inspection as well as the structural analysis of exploration drift walls oriented subparallel to the analysed boreholes are used for alternatively evaluated RQD values. Results show that, in most cases, the RQD index measured directly on a drill core section reaches lower values (about 10%–30%) than the RQD evaluated by alternative methods. Significant differences in determination of the rock mass failure degree using classical and alternative methods may occur, especially in sections with higher frequency of the metamorphic foliation planes created by biotite-rich bands or by dark-coloured melanosome layers. The nature of biotite itself is favourable for the creation of pre-disposed jointing planes, in which the increased drill core disintegration caused by drilling technology or core handling can occur. Results show it is highly appropriate to make these comparisons on a larger scale and thus verify whether the observed differences affect the qualitative classification of the rock mass.

Methods of Determining Rock Mass Freezing Depth for Shaft Sinking in Difficult Hydrogeological and Geotechnical Conditions/Określenie Głębokości Zamrażania Górotworu Dla Potrzeb Głębienia Szybów W Trudnych Warunkach Hydrogeologicznych I Geotechnicznych

2014 ◽  
Vol 59 (2) ◽  
pp. 517-528
Author(s):  
Robert Duda
Keyword(s):  
Rock Mass ◽  
Drilling Fluid ◽  
Copper Mining ◽  
Mining District ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
Heterogeneous Rocks ◽  
Source Data ◽  
Freezing Depth ◽  
Shaft Sinking

Abstract Methods of determining the depth of rock mass freezing for the purpose of shaft sinking in solid rocks in difficult hydrogeological and geomechanical conditions are analyzed in this paper. There are presented factors on the basis of which the freezing depth can be determined in heterogeneous rocks media. The author focuses on the source of problems with establishing parameters used for defining the freezing depth. A method of interpreting hydrogeological and geomechanical source data is presented on two examples of weak and medium compact sandstones freezing for the purpose of shaft sinking in the Legnica-Głogów Copper Mining District, south-western Poland. Moreover, a general algorithm for determining the rock mass freezing depth is given. The following main criteria of freezing depth evaluation have been assumed: hydraulic conductivity values, porosity, rock quality designation index (RQD) and Protodiakonow’s rock compaction index. The outflow of drilling fluid in the exploration borehole was taken into account as a complementary criterion. The practical use of the algorithm was exemplified by a geological profile.

GEOMETRI PELEDAKAN BERDASARKAN ROCK MASS RATING (RMR) DAN FRAGMENTASI HASIL PELEDAKAN

2020 ◽  
Vol 4 (4) ◽  
pp. 209-215
Author(s):  
Aprilliana ◽  
Taufik Toha ◽  
Budhi Kuswan Susilo
Keyword(s):  
Rock Mass ◽  
Rock Mass Rating ◽  
Rock Quality Designation ◽  
Rock Quality

Peledakan merupakan salah satu metode pembongkaran lapisan batuan. Hasil dari peledakan ini adalah fragmentasi batuan yang berukuran beragam. Salah satu faktor yang mempengaruhi ukuran fragmentasi ini sangat dipengaruhi oleh geometri peledakan. Geometri peledakan sulit untuk dievaluasi karena belum pernah melakukan analisis fragmentasi hasil peledakan menggunakan software. Tujuan dari penelitian ini adalah mengevaluasi geometri peledakan, Identifikasi kelas massa batuan menggunakan Rock Mass Rating (RMR), dan menganalisis fragmentasi hasil peledakan. Metode identifikasi kelas massa batuan dalam penelitian ini menggunakan metode rock mass rating (RMR) meliputi kuat tekan batuan, rock quality designation (RQD), jarak diskontinuity, kondisi diskontinuity, dan air tanah. Sedangkan fragmentasi hasil peledakan dianalisis menggunakan software split desktop. Pada analisis ini foto fragmentasi hasil peledakan di front dan di disposal diambil langsung sebagai data utama yang menjadi dasar dari analisis ini. Berdasarkan hasil analisis RMR diketahui bahwa batuan yang dibongkar adalah jenis claystone dengan rating kuat tekan 1, RQD 8, Jarak diskontinuitas 15, kondisi diskontinuitas 0, kondisi air tanah 15. Jadi total rating RMR 39 yang berarti batuan ini tergolong batuan jelek atau lunak. data diketahui bahwa batuan yang diledakkan merupakan jenis claystone kelas IV yang berarti jelek atau lunak, Hasil analisis fragmentasi hasil peledakan di disposal lebih kecil dan seragam dibandingkan dengan fragmentasi di front, perbedaan ukuran fragmentasi ini akibat adanya pengaruh dari aktivitas gali muat dan angkut material dari front ke disposal. Produktivitas excavator sudah sesuai dengan buku panduan yang berarti fragmentasi hasil peledakan sudah baik sehingga geometri peledakan tidak perlu diperbaiki.

Application and Improvement of Rock Quality Designation (RQD)

2015 ◽  
Vol 744-746 ◽  
pp. 1371-1373 ◽  
Author(s):  
Zhi Peng Zhao ◽  
Jun Chao Zhi
Keyword(s):  
Rock Mass ◽  
Statistical Method ◽  
Rock Block ◽  
Rock Quality Designation ◽  
Rock Quality

When using Rock Quality Designation (RQD) method to evaluate rock mass integrity, the premises are often neglected and there are some limitations in RQD method. This study proposes a hole section statistical method and a rock block coefficient to supplement and improve the limitations of RQD method. The accuracy is verified by applying it to a reservoir.

Prediction of end-bearing capacity of rock-socketed shafts considering rock quality designation (RQD)

2010 ◽  
Vol 47 (10) ◽  
pp. 1071-1084 ◽  
Author(s):  
Lianyang Zhang
Keyword(s):  
Compressive Strength ◽  
Rock Mass ◽  
Unconfined Compressive Strength ◽  
Empirical Relation ◽  
Intact Rock ◽  
Engineering Practice ◽  
Rock Quality Designation ◽  
End Bearing Capacity ◽  
Rock Quality ◽  
Empirical Relations

Existing empirical methods for determining the end-bearing capacity, qmax, use empirical relations between qmax and the unconfined compressive strength of intact rock, σc. As rock-socketed shafts are supported by the rock mass, not just the intact rock, one should consider not only the intact rock properties, but also the influence of discontinuities on rock mass properties when determining qmax. Although semi-empirical and analytical methods have been developed that can consider the effect of discontinuities, they are more complicated than the empirical relations and require information about discontinuities that is often not available or difficult to obtain in engineering practice. In this paper, an empirical relation between qmax and the unconfined compressive strength of rock mass, σcm, is developed. The new empirical relation explicitly considers the effect of discontinuities represented by rock quality designation (RQD), which is the parameter normally obtained in engineering practice. The accuracy of the expression for estimating σcm based on RQD is verified by comparing its estimation values with those from the existing empirical expressions based on rock mass classification. Two examples are presented to show the application of the newly developed empirical relation between qmax and σcm.

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