WebThe RQD can be estimated from average joint spacing based on the following equation by Priest and Hudson (1976): RQD = 100 e-.1l (.1l + 1) (1) where λ = 1/(joint frequency) Figure 2. Relationship between discontinuity spacing and RQD, after Bieniawski (1989). WebFeb 22, 2024 · Rock quality designation (RQD) is a reliable geomechanical parameter, extensively used in geotechnical engineering to obtain proper design of large-scale engineering infrastructures. RQD is traditionally …
Rippability of Rock - LITERATURE REVIEW - RIPPABILITY …
The RQD is a modified percent core recovery that incorporates only sound pieces of core that are 100 mm or greater in length along the core axis (Eq. 2). For RQD determination, the International Society of Rock Mechanics (ISRM) recommends a core size of at least NX (54.7 mm) drilled with double-tube core … See more For the excavation purposes Frankfin et al. (1971) proposed Discontinuity Strength Classification in which two rock mass properties, namely fracture index and point load index play major roles. Based on the Geomechanics … See more The relationship between rock mass quality and ease of excavation was developed by Abdullatif and Cruden (1983). They compared Barton et al. (1974) rock mass quality Q and Bieniawski (1976) RMR systems. … See more Regarding the observations with respect to excavation, Pettifer and Fookes (1994) Revised Excavatability Graph model was also used. Pettifer and Fookes (1994) proposed revision of … See more WebCHARTS SHOW RIPPABILITY OF ROCK FORMATIONS. Charts showing performance of the Kelley KR9 and KR8 Rippers in various materials have been developed by Kelley Products, a division of Crutcher-Rolfs-Cummings, Inc., Houston, Tex. The guides were prepared from actual performance data related to seismic wave velocities. The tables show when a … bits and pieces durban
Excavatability and the effect of weathering degree on the ...
WebRock mass classification schemes such as the Q System and Rock Mass Rating (RMR) System have been designed for prediction of tunnel support, but these systems can be … Webjoints and fracture plans, so RQD can be involved in excavation assessment methods. For the development of a precise rippability assessment method complete pool of information regarding rock mass properties and machine, parameters shall be included, as rippability depends on both rock mass and ripper machine properties. WebMay 9, 2013 · The rippability index was defined for assessing overburden loosening by rippers (Caterpillar Inc. 1988). The seismic wave velocity of the rock mass measured in … bits and pieces driffield