scholarly journals Assessment of block size distribution in fractured rock mass and its influence on rock mass mechanical behavior

AIP Advances ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 035124
Author(s):  
Wenli Yao ◽  
Sharifzadeh Mostafa ◽  
Zhen Yang
Keyword(s):  
Rock Mass ◽  
Mechanical Behavior ◽  
Size Distribution ◽  
Fractured Rock ◽  
Block Size ◽  
Fractured Rock Mass ◽  
Block Size Distribution

scholarly journals CSD correction as a tool for estimating 3d block size distribution.

2013 ◽  
Vol 47 (4) ◽  
pp. 1854
Author(s):  
M. Rusi ◽  
P. Hoxha
Keyword(s):  
Rock Mass ◽  
Size Distribution ◽  
Three Dimensional ◽  
Block Size ◽  
Economic Consequences ◽  
Major Question ◽  
Thin Sections ◽  
Matrix Rock ◽  
Tbm Excavation ◽  
Block Size Distribution

For the headrace Moglicë-Grabovë, part of Devoll Hydropower Project in Albania, two different techniques of tunnelling are planned: DS TBM for the Flysch series starting in Moglicë and Drill & Blast for the Ophiolite section, starting in Grabovë. A major question concerning the tunnelling seems to find the point where DS-TBM excavation from the Moglicë side should stop to “wait” for the Drill&Blast excavation from the Shemsit access tunnel side. Assumed that the so called “block in matrix” rock mass is very unfavourable, respectively disqualifying for TBM excavation. These mixtures of hard blocks embedded in weaker and finer matrix that are very difficult to characterize, frequently challenge the engineering geologists with the characterization, design and construction problems associated with them. Evaluating Block Size Distribution in the BiM rock zone of this project area has been only the first step in characterizing all the geological and geotechnical parameters of the rock mass which will influence a decision that has major economic consequences. CSDCorrections 1.39 is the program used to convert the two dimensional data gathered from thin sections, outcrops, photographs etc. to true three dimensional crystal size distributions (CSD).

scholarly journals The Impact of Fracture Persistence and Intact Rock Bridge Failure on the In Situ Block Area Distribution

2021 ◽  
Vol 11 (9) ◽  
pp. 3973
Author(s):  
Thomas Strauhal ◽  
Christian Zangerl
Keyword(s):  
Rock Mass ◽  
Size Distribution ◽  
Block Size ◽  
Intact Rock ◽  
Rock Bridge ◽  
Block Area ◽  
The Mean ◽  
Bridge Failure ◽  
Block Size Distribution

The in situ block size distribution is an essential characteristic of fractured rock masses and impacts the assessment of rockfall hazards and other fields of rock mechanics. The block size distribution can be estimated rather easily for fully persistent fractures, but it is a challenge to determine this parameter when non-persistent fractures in a rock mass should be considered. In many approaches, the block size distribution is estimated by assuming that the fractures are fully persistent, resulting in an underestimation of the block sizes for many fracture geometries. In addition, the block size distribution is influenced by intact rock bridge failure, especially in rock masses with non-persistent fractures, either in a short-term perspective during a slope failure event when the rock mass increasingly disintegrates or in a long-term view when the rock mass progressively weakens. The quantification of intact rock bridge failure in a rock mass is highly complex, comprising fracture coalescence and crack growth driven by time-dependent changes of the in situ stresses due to thermal, freezing-thawing, and pore water pressure fluctuations. This contribution presents stochastic analyses of the two-dimensional in situ block area distribution and the mean block area of non-persistent fracture networks. The applied 2D discrete fracture network approach takes into account the potential failure of intact rock bridges based on a pre-defined threshold length and relies on input parameters that can be easily measured in the field by classical discontinuity mapping methods (e.g., scanline mapping). In addition, on the basis of these discrete fracture network analyses, an empirical relationship was determined between (i) the mean block area for persistent fractures, (ii) the mean block area for non-persistent fractures, and (iii) the mean interconnectivity factor. The further adaptation of this 2D approach to 3D block geometries is discussed on the basis of general considerations. The calculations carried out in this contribution highlight the large impact of non-persistent fractures and intact rock bridge failure for rock mass characterization, e.g., rockfall assessment.

Study of the geometrical size effect of a fractured rock mass based on the modified blockiness evaluation method

2018 ◽  
Vol 11 (11) ◽  
Author(s):  
Qingfa Chen ◽  
Tingchang Yin ◽  
Wenjing Niu ◽  
Wenshi Zheng ◽  
Junguang Liu
Keyword(s):  
Rock Mass ◽  
Size Effect ◽  
Evaluation Method ◽  
Fractured Rock ◽  
Fractured Rock Mass ◽  
Geometrical Size

Application of Borehole Camera Technology in Fractured Rock Mass Investigation of a Submarine Tunnel

2019 ◽  
Vol 83 (sp1) ◽  
pp. 609 ◽  
Author(s):  
Zengqiang Han ◽  
Chuanying Wang ◽  
Sheng Hu ◽  
Yiteng Wang
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Fractured Rock Mass ◽  
Borehole Camera
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