The Confidence-degree of Mechanical Parameters of Rock Mass and Its Reliability Test

Author(s):  
Zhiquan Huang ◽  
Baoliang Jiang
2014 ◽  
Vol 1079-1080 ◽  
pp. 266-271
Author(s):  
Wen Hui Tan ◽  
Zhong Hua Sun ◽  
Ning Li ◽  
Xiao Hong Jiang

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhiqiang Li ◽  
Guofeng Liu ◽  
Shuqian Duan ◽  
Shufeng Pei ◽  
Changgen Yan

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.


2012 ◽  
Vol 204-208 ◽  
pp. 727-731
Author(s):  
Yuan Zhao ◽  
Liang Qing Wang ◽  
Ye Liang

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.


2013 ◽  
Vol 368-370 ◽  
pp. 1551-1555
Author(s):  
Si Yu Wu ◽  
Bo Huang ◽  
Rui Jun Liu

Firstly, the stability of the slope need to determine mechanical parameters of slope rock mass such as deformation modulus, Poissons ratio, cohesion and internal friction angle, etc. For intact rocks, the mechanical parameters mentioned before are easy to determined. While the stability of slope rock mass is controlled by the deformation and intensity. Therefore, how to determine the mechanical parameters of the structure is the key to analyze the stability of slope rock mass. This paper intends to set the slope rock mass below some extra-large bridge as the research object and use numerical calculation to determine the mechanics parameters of rock mass structure plane on the basis of rock sample mechanics test results.


1999 ◽  
Vol 19 ◽  
Author(s):  
Kaustubh Mani Nepal

In-situ testing of rock mechanical parameters is essential for rock mass characterisation. The rock mass characterisation is important in design and construction of underground works forming major component of Hydropower projects. The major civil structures of most of the hydropower projects planned in Nepal have to be founded on complex rock formations on fragile geological environments. In-situ rock mechanics tests carried out at various hydropower projects sites are described and the findings are summarised.


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