Kausar Sultan shah; Mohd Hazizan bin Mohd Hashim; Hafeez Ur Rehman; Kamar shah bin Ariffin
Abstract
The significance of rock failure can be found from the fact that microfracture genesis and coalescence in the rock mass results in macroscale fractures. Rock may fail due to an increase in the local stress, natural fractures, weathering inducing micro-crack genesis, coalescence, and propagation. Therefore, ...
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The significance of rock failure can be found from the fact that microfracture genesis and coalescence in the rock mass results in macroscale fractures. Rock may fail due to an increase in the local stress, natural fractures, weathering inducing micro-crack genesis, coalescence, and propagation. Therefore, a comprehensive understanding of the micro-scale failure mechanism of various weathering grade sandstones based on micro-level observation and microstructure-based simulation is essential. The microscale failure response of various weathering grade sandstones is studied under the wet and dry cycles. Each sample is tested for the micro-structure and micro-fracture characteristics using the image analysis. Furthermore, the micrographs obtained are also used to create the microstructure-based models, which are then simulated in the ANSYS software. The findings indicate that the moderately weathered sandstones indicate less weight reduction than the slightly weathered sandstone. The results obtained also demonstrate that the wet and dry cycles have little effect on the particle shape and size. However, variation in the particle shape and size implies that this is a result of the prevailing interaction of rock and water particle. The microscale simulation reveal that both UCS and BTS decrease from 37 MPa to 19 MPa and 9 MPa to 4 MPa as the density of the micro-structure increases. The results reveal that the primary fracture deviation from the loading axis increases with increasing density in the micro-structural micro-structures, although this effect reduces with further increasing density in the micro-structures.
K.S. Shah; M. H. Mohd Hashim; K.S. Ariffin; N. F. Nordin
Abstract
The stability analysis of rock slopes is a complex task for the geotechnical engineers due to the complex nature of the rock mass in a tropical climate that often has discontinuities in several forms, and consequently, in several types of slope failures. In this work, a rock mass classification scheme ...
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The stability analysis of rock slopes is a complex task for the geotechnical engineers due to the complex nature of the rock mass in a tropical climate that often has discontinuities in several forms, and consequently, in several types of slope failures. In this work, a rock mass classification scheme is followed in a tropical environment using the Rock Mass Rating (RMR) and Geological Strength Index (GSI) combined with the kinematic investigation using the Rocscience Software Dips 6.0. The Lafarge quarry is divided into ten windows. In the RMR system, the five parameters uniaxial compressive strength (UCS), rock quality designation (RQD), discontinuity spacing, discontinuity condition, and groundwater conditions are investigated. The RMR values range from 51 to 70 (fair to good rock mass), and the GSI values range from 62 to 65 (good to fair rock mass). There is a good and positive correlation between RMR and GSI. The kinematic analysis reveals that window A is prone to critical toppling, window H to critical wedge-planar failure, and window G to critical wedge failure. From the results obtained, it can be concluded that the kinematic analysis combined with the rock mass classification system provides a better understanding to analyze the rock slope stability in a tropical climate compared with considering the rock mass classification system individually.
