Abstract and Figures. Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump ...
Determining permeability of fractured rocks is a focal point in engineering projects. Many methods have been developed for direct in situ determination of the hydraulic parameter; nevertheless, especially in the preliminary stages of rock mass characterization, empirical correlations are used to estimate the rock permeability. This study proposes a …
Rock quality designation (RQD) is a standard technique in the mining industry for the qualitative and quantitative assessment of rock quality and degree of jointing, fracturing, and shearing in a rock mass. RQD is defined as the percentage of intact drill core pieces longer than 10 cm recovered during a single core run (Abzalov, 2016), and the general equation …
Cecil 1/91 published in 1970 his work on correlation or RQD with rock bolt-shotcrcte support as uscd in Scandinavia. Merritt 1/21 in 1972 made use of his reccnt expcricncc and the works cited above to present an improved version based on 58 cases which included tunnel widths ranging from 2 m (6 ft) to 20 m (60 ft).
Coal strength is a function of joint spacing, lithotype, and stress paths, making coal strength scale and stress path dependent, typical of a rock mass (Deisman et al., 2008, Medhurst and Brown, 1997, St. George, 1995). The difficulty in coal seams comes when attempts are made at assessment of the intact properties of coal, as samples used …
This study investigates the correlation of the uniaxial compressive strength (UCS) and the point load test (PLT) index Is(50), bulk density, water absorption and the RQD properties of the Sudanese ...
YuanDian No.2 coal mine is located in the north of Bozhou city, Anhui province of China. In 2019, the colliery rented an open-type hard rock TBM (Fig. 5a) to construct two roadways for the 7 th mining area: west horizontal rail haulage entry and west rail haulage rise (19° incline) as shown in Fig. 5b and c. The horizontal entry has a …
The selected ERT points provide us 28 resistivity (inverted) values at the same depths as the RQD values of four wells. We use 28 RQD values (obtained from four wells) and 28 resistivity values ... However, RQD further cannot evaluate the rock mass strength after RQD and resistivity 10,000 Ωm. But resistivity can further assess …
Section snippets Background: directional dependence and upscaling of RQD. The RQD rating ( et al., 1967) provides a quantitative measure of the degree of jointing or fracturing of rock mass from boreholes, consisting of 100 times the ratio between the total length of core pieces larger than 100 mm and the total core run length.
Rock Quality Designation (RQD) is among the widely used measures of the quality of rock masses and can be derived through Monte Carlo stochastic process-based fracture network simulations. However, repeated simulations can yield variable RQD results. Here, we introduce a four-step approach that incorporates class ratio analysis to …
The focus of this paper is to present the data analysis used to correlate the point load test index (Is 50) with the uniaxial compressive strength (UCS), and to propose appropriate Is50 to UCS conversion factors for different coal measure rocks. The rock strength determined by the PLT, like the load frame strengths that they estimate, are an ...
In determining the RQD index only sound core pieces longer than 100 mm are to be considered (Figs. 1 and 2). Accordingly, RQD enables core logging as well as evaluation of the degree of jointing along the core drill hole, the so-called "core run", whereby RQD gives an average measurement of the degree of jointing along the total core run length
Fracture spacing (or RQD) Uniaxial compressive strength (or axial Point Load Testing) Diametral Point Load Testing. The moisture sensitivity adjustment has also been …
Determining Rock Quality Designation (RQD) ... 3.2.5 sound core—any core which is fresh to moderately weathered and which has sufficient strength to resist hand breakage. 4. Summary of Test Method ... PO Box C700, West Conshohocken, PA 19428-2959, United States. L7HK6 WDQGDUGV KWWSV˛ VWDQGDUGV LWHK DL ' RFXPHQW3 UHYLHZ.
Such rocks may be recovered intact, with RQD=100, yet their lateral strength may be one-sixth of their axial (6). Since the most severe loading applied to coal mine roof is normally lateral, caused by horizontal stress, bedding plane shear strength is a critical parameter. Unfortunately, bedding plane shear strength is almost never tested
Based on mapping of rock formations by 17 independent professionals at different locations in Australia and South Africa, it is shown that differences in assessed …
The role and importance of rock mass classification systems from past to present in engineering designs are indisputable. Therefore, the correct estimation of the parameters that make up these systems is essential in terms of reliability, time, and economy. One of the crucial parameters commonly used in rock mass classification is …
Hence, us ing this equatio n, data ana lysis was carried out to find the relatio nship be tween RQD andf racture frequ enc y in Monz onit e Porph yry. Th e graph and eq uation deri ved from this ...
The rock quality designation (RQD) is a commonly used index for the description of rock mass fractured state. The RQD was initially introduced for civil engineering applications, and it has been quickly adopted in mining, engineering geology as well as geotechnical engineering. The success of the RQD is in great part, due to its simplicity. This paper …
Rock-quality designation ( RQD) is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. High-quality rock has an RQD of more than 75%, low quality of less than 50%. Rock quality designation ( RQD) has several definitions.
The RQD can also be used for calculating the Geological Strength Index (GSI): on the basis of several studies, Hoek et al. [7] suggested the following simple formula for GSI calculation: GSI = 1.5 ...
PDF | On Jun 23, 2013, Ahmed Abu El-Ela and others published Reliability Based Design of Shallow Foundations on Jointed Rock Masses using RQD and the Uniaxial Compressive Strength of Intact Rock ...
A database of 127 training and 32 testing datasets collected from NATM-3 of the tunnel was constructed. The input parameters are the Uniaxial Compressive Strength (UCS), Rock Quality Designation ...
Finally, the empirical methods based on RQD are used to determine the deformation modulus and unconfined compressive strength of rock masses at five different sites including 13 cases, and the ...
Along RQD profile Q, three deep weathered zones of 200, 180 and 190 m thickness were revealed at distance of 30–180, 320–410 and 550–700 m, whereas other …
Rock Quality Designation (RQD) is a measure of quality of rock core taken from a borehole. RQD signifies the degree of jointing or fracture in a rock mass measured in …
The RQD calculation results of the proposed method and the traditional single-model approach exhibit differences, which diminish with increasing model sizes. …
It is shown that the empirical methods based on RQD tend to give deformation modulus values close to the lower bound (conservative) and unconfined compressive …
To calculate RQD, follow these steps: Measure the total length of the core sample in meters (L). Determine the total length of intact pieces of rock that are longer than 10 cm (I). Calculate the RQD using the formula: RQD = (I / L) x 100. For example, if the core sample is 10 meters long and there are 6 meters of intact pieces of rock longer ...