scholarly journals Rock Mass Rating and Geological Strength Index of rock masses of Thopal-Malekhu River areas, Central Nepal Lesser Himalaya

2013 ◽  
Vol 16 ◽  
pp. 29-42 ◽  
Author(s):  
Jaya Laxmi Singh ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Rock Mass ◽  
Surface Condition ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Slopes ◽  
Lesser Himalaya ◽  
Rock Masses ◽  
Strength Index ◽  
Rock Mass Structure ◽  
Exposed Rock

The rock slopes of the Thopal-Malekhu River areas, Lesser Himalaya, were characterized applying various systems of rock mass classification, such as Rock mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well exposed rock formations of the Nawakot and Kathmandu Complexes, across the Thopal-Malekhu River areas. In RMR system, mainly five parameters viz. Uniaxial Compressive Strength (UCS) of rock, Rock Quality Designation (RQD), spacing of discontinuity, condition of discontinuity, and groundwater condition were considered. The new GSI charts, which were suitable for schistose and much disintegrated rock masses, were used to characterize rock slopes based on quantitative analysis of the rock mass structure and surface condition of discontinuities. RMR ranged from 36 to 82 (poor to very good rock mass) and GSI from 13.5±3 to 58±3 (poor to good rock mass). Slates (of the Benighat Slate) are poor rock masses with low strength, very poor RQD, and close to very close spacing of discontinuity, and dolomites (Dhading Dolomite) are fair rocks with disintegrated, poorly interlocked, and heavily broken rock masses yielding very low RMR and GSI values. Phyllites (Dandagaun Phyllite), schist (Robang Formation) and quartzite (Fagfog Quartzite, Robang Formation and Chisapani Quartzite), dolomite (Malekhu Limestone), and metasandstone (Tistung Formation) are fair rock masses with moderate GSI and RMR values, whereas quartzose schist and gneiss (Kulekhani Formation) are very good rock masses having comparatively higher RMR and GSI. The relationship between GSI and RMR shows positive and good degree of correlation. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8882   Bulletin of the Department of Geology Vol. 16, 2013, pp. 29-42

Rock quality designation (RQD): time to rest in peace

2017 ◽  
Vol 54 (6) ◽  
pp. 825-834 ◽  
Author(s):  
P.J. Pells ◽  
Z.T. Bieniawski ◽  
S.R. Hencher ◽  
S.E. Pells
Keyword(s):  
Rock Mass ◽  
Classification Systems ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Quality Designation ◽  
Strength Index ◽  
Rock Quality ◽  
Rock Formations ◽  
The Look ◽  
Definition Of

Rock quality designation (RQD) was introduced by Don Deere in the mid-1960s as a means of using diamond core to classify rock for engineering purposes. Subsequently, it was incorporated into the rock mass rating (RMR) and Q-system classification methods that, worldwide, now play substantial roles in rock mechanics design, whether for tunnels, foundations, rock slopes or rock excavation. It is shown that a key facet of the definition of RQD is ignored in many parts of the world, and it is noted that there are several inherent limitations to the use of RQD. 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 RQD values result in significant errors in computed RMR and Q ratings, and also in geological strength index (GSI) and mining rock mass rating (MRMR). The introduction of a look-up chart for assessing GSI has effectively removed the need to measure, or estimate, RQD. It has been found that GSI values derived from the look-up chart are as valid as those derived by calculation from the original component parameters, and are satisfactorily consistent between professionals from diverse backgrounds. The look-up charts provide a quick and appropriate means of assessing GSI from exposures. GSI is, in turn, a useful rock mass strength index; one new application is presented for assessing potential erosion of unlined spillways in rock. Incorporation of RQD within the RMR and Q classification systems was a matter of historical development, and its incorporation into rock mass classifications is no longer necessary.

scholarly journals Geology and rockmass condition of Dhulikhel-Panchkhal area, Kavre District, Central Nepal Lesser Himalaya

2013 ◽  
Vol 15 ◽  
pp. 1-14
Author(s):  
Prem Nath Paudel ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Rock Mass ◽  
Rock Type ◽  
Physical And Mechanical Properties ◽  
Geological Mapping ◽  
Rock Mass Rating ◽  
Lesser Himalaya ◽  
Rock Masses ◽  
Northern Limb ◽  
Rock Types ◽  
Central Nepal

A geological mapping was carried out and the rock mass characteristics of the Lesser Himalayan rocks distributed in the Dhulikhel-Panchkhal area (Kavre Distric) were studied along with their physical and mechanical properties. The lithological units distributed in the study area belong to the Benighat Slate of the Upper Nawakot Group and the Bhimphedi Group as separated by the Chak-Rosi Thrust. The lithological units strike NW-SE and dip southwards forming the eastern closure of part of the northern limb of the Mahabharat synclinorium. The area comprises mainly micaceous quartzite, psammitic schist, metasandstone and metasiltstone. Micaceous quartzite is a rock type of the Kalitar Formation, Chisapani quartzite and the Markhu Formation. The Markhu quartzite is slightly calcareous. Psammitic schist is a rock type of the Kulekhani Formation and the Markhu Formation. Metasandstone and metasiltstone are the rock types of the Tistung Formation. The rock masses consist mainly of three to four major joint sets including the joint parallel to foliation. The discontinuity characteristics indicate that the rocks are blocky in nature, and nearly smooth to rough surface with soft filling aperture. The rock mass is nearly fresh, indurated and stiff. The slopes are influenced by stable and unstable wedges, plane and toppling failures. The rock masses are classified into fair to good rock classes according to rock mass rating system. DOI: http://dx.doi.org/10.3126/bdg.v15i0.7412 Bulletin of the Department of Geology, Vol. 15, 2012, pp. 1–14

scholarly journals Engineering geological characteristics based on rock mass rating (RMR) and geological strength index (GSI) in Tunnel Number 1 of the Sigli-Aceh toll road

2021 ◽  
Vol 325 ◽  
pp. 01014
Author(s):  
Jabnes Satria ◽  
I Gde Budi Indrawan ◽  
Nugroho Imam Setiawan
Keyword(s):  
Rock Mass ◽  
Poor Quality ◽  
Geological Mapping ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Strength Index ◽  
Geological Investigation ◽  
Tunnel Support ◽  
Toll Road ◽  
Tunnel Number

This paper presents engineering geological investigation results in the form of rock mass characteristics for tunnel number 1 of the Sigli-Aceh toll road. The investigation was carried out through geological mapping, core drill evaluation, and laboratory tests. In this research, the rock mass rating (RMR) and Geological Strength Index (GSI) were applied for the rock mass classifications. The measurement of rock mass quality is then used to determine the excavation method and tunnel support system on the SigliAceh toll road. The results showed that the research location consisted of calcareous sandstone with poor to good-quality (GSI (21.7 - 85.5), RMR (32.0 - 67.6)), and sandstone with good quality (GSI (86.3 - 86.9), RMR (64.0 - 65.0)). The poor quality rock masses were mainly caused by weathering effect. In addition, this research also analyzes the relationship between RMR and GSI based on the type and quality of rocks in the research location so that this correlation can be used in other areas with similar rock type and quality to this research location.

scholarly journals DETERMINATION OF NUCLEAR POWER PLANT SITE IN WEST BANGKA BASED ON ROCK MASS RATING AND GEOLOGICAL STRENGTH INDEX

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Irvani Irvani ◽  
Wahyu Wilopo ◽  
Dwikorita Karnawati
Keyword(s):  
Rock Mass ◽  
Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Friction Angle ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Strength Index ◽  
Energy Agency ◽  
Discontinuity Orientation

Indonesian government through the NationalAtomic Energy Agency has planned to build anuclear power plant. One of the proposed sitesis in West Bangka Regency, Bangka BelitungArchipelago Province. The engineering geologyof this area is, however, not fully understood andrequires further investigations. Engineering geology investigations were carried out by assessing therock mass quality and bearing capacity based onfield observation and drilling data. The assessmentwas conducted using Rock Mass Rating (RMR)and Geological Strength Index (GSI) classifications.The rock masses in the study area were dividedinto four units, namely units of sandstone, granite,mudstone and pebbly sandstone. The RMR andGSI values in the study area were influenced by theparameters of discontinuity space density, the slopeof discontinuity orientation, grade of weatheringand groundwater conditions. The assessment showsthat the granite unit had the best quality which wasshown by a 53 average RMR value and 66 GSIvalue. Based on the average RMR value, the graniteunit was estimated to have cohesion value between0.2 and 0.3 MPa, friction angle between 25° and35°, and allowable bearing pressure between 280and 135 T/m2. Based on the GSI value, the graniteunit was estimated to have uniaxial compressivestrength value between 1.0465 and 183.8 MPa, ten-sile strength between (-0.0122) and (-5.2625) MPa,rock mass strength values between 24.5244 and220.351 MPa, and modulus of deformation withina range of 1.73 - 86.68 GPa. The Granite Unit wasconsidered to be the most appropriate location forthe nuclear power plants.

Sign in / Sign up

Export Citation Format

Share Document