scholarly journals Empirical methods of calculating the mechanical parameters of the rock mass

2016 ◽  
Author(s):  
Balázs Vásárhelyi ◽  
Dorottya Kovács
Keyword(s):  
Rock Mass ◽  
Mechanical Parameters ◽  
Empirical Methods

Stochastic Three-Dimensional Joint Geometry Model and the Properties of REV for a Jointed Rock Mass

2014 ◽  
Vol 1079-1080 ◽  
pp. 266-271
Author(s):  
Wen Hui Tan ◽  
Zhong Hua Sun ◽  
Ning Li ◽  
Xiao Hong Jiang
Keyword(s):  
Rock Mass ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Open Pit ◽  
Mechanical Parameters ◽  
Geometry Model ◽  
Joint Geometry ◽  
3D Network

The lithology of rock mass isnon-homogeneity，anisotropy, andexists size effect. The mechanical parameters of rock mass gotten by engineeringapproaches cannot reflect these properties. Therefore, a newmethod of determining the mechanical parameters of jointed rock mass isproposed: gneiss in Shuichang open-pit mine was selected as a case, thefracture system of the rock mass was measured and analyzed by non-contactmeasuring system of 3GSM and probabilisticmethod,the probability distributions of geometry parameters were analyzed and a 3Djoint geometry model was made by using the program of 3D network modeling.Cubes with different sizes were selected to be tested by tri-axial compressionof numerical simulation with 3DEC based on the 3D network model of joints,thus, the REV and its mechanical parameters were determined, which providedcredible parameters for slope stability analysis.

scholarly journals Sensitivity Analysis in the Estimation of Mechanical Parameters of Engineering Rock Mass Based on the Hoek–Brown Criterion

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhiqiang Li ◽  
Guofeng Liu ◽  
Shuqian Duan ◽  
Shufeng Pei ◽  
Changgen Yan
Keyword(s):  
Rock Mass ◽  
Triaxial Compression ◽  
Damage Zone ◽  
Surrounding Rock ◽  
Geological Strength Index ◽  
Sensitivity Factor ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Disturbance Factor

Geological strength index GSI, disturbance factor (D), material constant mi, and uniaxial compressive strength σci of the intact rock are essential input parameters IPs of the Hoek–Brown H−B criterion. Mechanical parameters MPs of the engineering rock mass, including elastic modulus E, cohesion c, and internal friction angle φ estimated by the H–B criterion, and the predicted excavation response of surrounding rock, including the displacement and excavation damage zone EDZ based on the MPs, are of high relevance with the four IPs of the H–B criterion. In this paper, the deep and huge underground cavern excavated in basalt from a hydropower station under construction in the southwest of China is used to analyse the sensitivity of the IPs on the MPs, the displacement, and EDZ of the surrounding rock mass. Firstly, the H–B criterion is applied to estimate the MPs, among which the IPs are obtained from a series of in situ and laboratory tests, including borehole camera observation, wave velocity test, uniaxial and triaxial compression tests, and so on. Secondly, the sensitivity relationships between IPs, MPs, and prediction results of displacement and EDZ are established and described quantitatively by the sensitivity factor (si). Results show that the MPs of the rock mass are more sensitive to GSI and D⋅GSI and σci are high-sensitivity parameters affecting the displacement and EDZ. Finally, the variations in the estimated MPs and associated prediction results concerning excavation response, which are caused by the uncertainties in the determination of the IPs, are further quantified. This study provides a straightforward assessment for the variability of the rock mass parameters estimated by the H–B criterion. It also gives a valuable reference to similar geotechnical engineering for the determination of rock mass parameters in the preliminary design.

scholarly journals Stability of a rock mass using the key block theory: a case study

2020 ◽  
Vol 150 ◽  
pp. 03024
Author(s):  
Y. Zerradi ◽  
A. Lahmili ◽  
M. Souissi
Keyword(s):  
Rock Mass ◽  
Underground Mines ◽  
The Finite Element Method ◽  
Empirical Methods ◽  
Mining Operations ◽  
Initial Equilibrium State ◽  
Eastern Zone ◽  
Geometrical Data ◽  
Key Block

In underground mines, excavating disturb the initial equilibrium state of the rock mass, and therefore require selection of a support in order to control the movement of rocks, avoid landslide and work safely. Thus, the progress of mining operations in the ST2 mineralization, in the eastern zone of the Bouazzer mine, is disrupted because of stability problems. On the basis of field observations and analyzes of core drill, the geological and structural study, carried out in this area, has shown the existence of three types of facies: altered and cracked diorite, cobaltiferous mineralization which is in contact with serpentinites. In fact, the empirical methods such as Barton, Bieniawski and the recommendations of the AFTES have qualified the rock mass as poor, furthermore they proposed as kind of supports: steel arches, shotcrete and rock-bolts. Numerical simulation by the finite element method proved to be very complex due to existence of several types of discontinuities (faults, shistosities and joints).These discontinuities are natural fractures that delimit various shapes and sizes of wedges, which can become detached from the roof or siding of the excavation and collapse under their own weight. Although the empirical methods cited above provide supports for each facies, however, this support is expensive and difficult to implement in practice because it must cover the entire surface of the excavation and thus not allowing to detect stable blocks that do not require a support. For this it was essential to carry out an analysis of wedges to better locate unstable blocks. The treatment of fracturing data has highlighted the presence of five sets of discontinuities of which three sets are principals and the other two are minor joints. Then, while taking into account the geometrical, mechanical data of the discontinuities as well as the geometrical data of the excavation, we were able to detect the shape and the size of the unstable blocks and the sets of discontinuities delimiting them and which favor their sliding and tilting. Thus, we calculated the number of anchor bolts needed to stabilize these blocks in order to ensure an acceptable safety factor. This study shows clearly how a wedge analysis of the rock mass can guide and optimize the support work.

Estimation of Rock Mass Deformation Modulus in Gas Pipeline Area Based on Different Methods

2012 ◽  
Vol 204-208 ◽  
pp. 727-731
Author(s):  
Yuan Zhao ◽  
Liang Qing Wang ◽  
Ye Liang
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Engineering Design ◽  
Deformation Modulus ◽  
Gas Pipeline ◽  
Mechanical Parameters ◽  
Strength Parameters ◽  
Rock Mass Deformation ◽  
Mass Classification ◽  
Mass Deformation

Deformation modulus plays an important role in evaluating slope stability of rock mass and conducting the geotechnical engineering design. Based on the research of geological properties, physical and mechanical parameters of predominant rock mass types for different formations from Zhongxian to Wuhan, China, deformation modulus values of gas pipeline area were estimated by using rock mass classification method in this paper. Comparisons were made amongst different formulas based on GSI, RMR and Q methods to suggest range values of deformation modulus for predominant rock mass types of different formations which gives instructions to estimate strength parameters of rock masses for similar projects.

scholarly journals Empirical and finite element based stability analysis of highway cut slopes in Uttarakhand Himalayan terrain, India

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hari Om Singh ◽  
Tariq Anwar Ansari ◽  
T. N. Singh ◽  
K. H. Singh
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Stability Analysis ◽  
Slope Stability ◽  
Kinematic Analysis ◽  
Empirical Methods ◽  
Geotechnical Data ◽  
Cut Slopes

AbstractThe present paper deals with different empirical methods and finite element method of slope stability analysis along National Highway (NH)-7, in Uttarakhand, India. The highway is only path in the hilly terrain of Lesser Himalayan for the public transport and have strategic importance due to militaries possession routes. This route is also significant due to having many holistic places, connecting to this. There was numerous landslides happened along the Highway in past due to various natural and anthropogenic activities. Hence, keeping an eye to the socio-economic development of the distant area, slope stability analysis is very crucial along the road cut sections. To identify the vulnerable locations and to collect the geotechnical data, the field investigation was carried out between Shivpuri to Byasi along NH-7 in Garhwal, Uttarakhand. Then geotechnical data was intended followed by rock mass characteristic, kinematic analysis and Qslope stability. Additionally, to review the stability results, numerical simulation (finite element method) was employed and slope mass behavior and failure mechanism of cut slopes were also evaluated. The rock mass characteristic and kinematic analysis illustrate normal and good variety of rock mass mainly wedge mode with flexural toppling of failure. The slope mass rating, continuous slope mass rating and also Qslope stability analysis showed, road cut slopes are critically stable and unstable. The results of different empirical methods shows a decent correlation between them. Further the numerical simulation analysis also evaluates that two cut slopes are unstable and other one is critically stable. This substantial empirical and numerical analysis of cut slopes provides a collective approach to stable and develop the holistic road corridor in Himalayan terrain.

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