Rock classification, parameters

FIGURE 7.2 Rock classification parameters (RQD index, number of cracks per metre, mean compact core length in metres, compressional wave velocity, and dynamic Young s modulus unweathered igneous and metamorphic rocks). Redrawn after Sjogren et al. (1979) and Barton (2007). 

Barton et al. (1975) pointed out that Bieniawski (1974), in his analysis of tunnel support, more or less ignored the roughness of joints, the frictional strength of the joint fillings and the rock load. They, therefore, proposed the concept of rock mass quality, Q, which could be used as a means of rock classification for tunnel support (Table 9.6). They defined the rock mass quality in terms of six parameters ... 

Exploratory Drifts provide basic rockmass parameters, which are used for rock classification. Drifts are also useful for insitu rock mechanic tests to determine mechanical characteristics of rockmass (Plate 12). 

The parameters of materials adopted for calculation are shown in Table 3. The control case results of different surrounding rock classification are shown in Table 4. 

Bieniawski (1989) developed a rock classification system called Rock Mass Rating (RMR) . Six parameters are used to classify a rock mass uniaxial... 

Classification of such a rock would employ the quartz (QZ)-plagioclase (PL)-alkali feldspar AF) Streckeisen ternary diagram, and so geochemical parameters describing the proportions of quartz, plagioclase and alkali feldspar can be obtained using the 7 matrix ... 

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

Classification of the rock mass around caverns was made according to the Rock Mass Rating (RMR) System (Bieniawski, 1989) and the Tunnelling Quality Index (Barton et al, 1974). Parameters were selected by the geological site investigation, the characteristic data for the intact rock, the joint sets and the in-situ stresses. 

Figure 3JO The classification of plutonic rocks using the parameters R1 and R2 (after dc la Roche...

Processing production of coal sample and physical mechanic parameters test are in strict accordance with the provisions of Measurement method of coal and rode physical and mechanical properties (GB/T 23561-2009), and Measurement method of coal seam impact tendency classification index (MT/T 866-2000). The experiment determined natural apparent density, compressive strength, consistent coefficient, elastic modulus, deformation modulus, wave velocity, rock burst energy index, elastic energy index, dynamic failure time, and other parameters. The determination results as shown in Table 1. 

C. Joint position coefficient B B value is determined by the relative azimuth angle of control joint surface and working face roof Based on classification method, joint fissure survey results in field and coal and rock physical and mechanical parameters test results. The dip angle of controlled joint surface is steep dip in working face roof Working face roof is normally horizontal. The joint position coefficient B of surrounding rock is 0.85 when it is classified by the unfavorable principle. This value is used to improve safety factor. 

Lucia, F. J., 1981. Petrophysical parameters estimated from visual descriptions of carbonate rocks. A field classification of carbonate pore space. SPE of AIME 56th Annual Fall Tech. Conf., San Antonio, Oct. 5-7, SPE 10073 ... 

A classification of rock masses is of primary importance in relation to the design of the type of tunnel support. Lauffer s (1958) classification represented an appreciable advance in the art of tunnelling since it introduced the concept of an active unsupported rock span and the corresponding stand-up time, both of which are very relevant parameters for determination of the type and amount of primary support in tunnels. The active span is the width of the tunnel or the distance from support to the face in cases where this is less than the width of the tunnel. The relationships found by Lauffer are given in Figure 9.16. 

Primary lining types and parameters can be selected from experiences on rock mass classifications and cavern spans (primary design) ... 

A review on the behaviour of anisotropic rocks, particularly metamorphic and sedimentary, was presented emphasizing on the classification of anisotropy with a simple system. In order, to predict the strength of anisotropic rock the modified Hoek Brown criterion and its recent applications have been presented and analyzed. It is evident that the parameter kp, reflects the anisotropy effect well in the criterion and it is well supported by recent research. 

The chemical composition of an igneous rock is also an important parameter of its classification. The chemical composition of a rock may be expressed by the types of minerals present and their relative abundances or in the rock color. Rocks may also be analyzed chemically using quantitative chemical analysis techniques to determine the relative proportions of chemical elements present. These chemical abundances can be used directly to classify igneous rocks. The chemical composition of the mother magma and to a lesser extent that of the country rock (i.e., host rock) largely controls the types of minerals which may be formed. 

Hence, proper assessment of both the anticipated seismic input and the prevailing soil conditions is an indispensable prerequisite in any SSI analysis. In modem seismic codes the site characterization for deep soil deposits is based almost exclusively on the near-surface region of the soil (often the top 30 m), disregarding the depth of the underlying rock. The representative average shear wave velocity to this depth in this deposit is used as parameter for the classification cf. Dobry et al. (2000). 

On the other hand, physical rock properties (for example elastic, electrical, nuclear properties) can be used to characterize rocks with respect to properties and parameters of interest (for example reservoir properties, geomechanical properties). This leads to a classification of rock properties into the following two main groups or types ... 

To obtain such a correlation, geophysical—particularly seismic— parameters for classification of rocks with respect to their general geotechnical constitution are recommended (see also Fig. 7.26). 

Track 4 gives the log-derived defect parameter D, calculated with Fp,soiid = 5800m/s (maximum measured value for the compact gneiss). The curve reflects a variation of rock quality. For comparison, the result of a visual geological classification from cores is plotted in Track 5. Sections with... 

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