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Rock anisotropy is a well-known phenomenon that occurs due to the heterogeneity of rock mass, but their influence on geotechnical design, especially in rock engineering, is often ignored. Every slope may be subjected to a certain mode of failure that can be evaluated using conventional and numerical methods. In this study, the rock slope is assessed numerically using 2D Limit Equilibrium Method (LEM) utilizing the Slide 2018 program in Rocscience software. The fundamental roles of the discontinuities present in the study area were evaluated to study the influence on slope stability. Anisotropic material model was incorporated in the LEM analysis to investigate the presence of discontinuities. A generalized anisotropy model was applied to represent the discontinuity behavior in the slope stability assessment. The relationship between the dipping angle of discontinuity and other significant parameters such as friction angle and cohesion effect on Factor of Safety (FoS) were studied. Sensitivity and probabilistic analysis were carried out to assess the uncertainties involved in the governing parameters. Anisotropy was modeled using 10° increments of angular range to represent the transition of shear strength from weak joint to rock mass strength. The results of FoS show that rock slope without anisotropy model is stable, and analysis employing anisotropic material model shows that the slope may fail. This study presents the approach of using the anisotropic material model for rock slopes where discontinuities are present, and slope failure occurs.

Quantitative weathering assessment using color changes is one of the new tools for slope stability assessment. In many other engineering field, CIELAB color space and image analytical tools have aided in enhancing the conventional method or inaccuracy due to the subjective and qualitative nature of visual assessment. This study focuses on the granitic rock slope surface assessment because of the predominant rock formation of granite in Malaysia. The 3D model of the rock slope was analyzed to extract the geological planes using compass plugin in Cloud Compare software and verified by manual compass mapping via scanline survey. Findings show that the a* and b* values increased with an increase in weathering results. This study focuses on the 50 points of measurement of rock slope and indicated a positive correlation of a* and b* with R2=0.9027. The image analysis result of the rock slope shows that major zoning (74%) is susceptible to failure due to structural control whilst another 26% are controlled by significant weathering in the grade IV-VI. This outcome is strongly verified via a geomechanical test, geological structure, and mineralogical assessment. The aforementioned mechanism is recommended in any geotechnical and technical purpose in enhancing the method of weathering assessment because image analysis provides reliable measurements in addition to the manual visual inspection.

Rock sizes and shapes influence the trajectories of rockfall. Thus, this study examined the bounce height and runout distance of falling rocks on the basis of different rock sizes, rock shapes, and ground surfaces. A laboratory experiment of rocks with various sizes falling from 35°, 45°, and 60° slope angles and vertically on different ground surfaces was conducted in this study to understand the mechanism of falling rocks. RocFall 5.0 (Rocscience), a 2D rockfall numerical simulation program, was used to perform the probable bounce height and runout distance for various rock shapes on different ground surfaces. The laboratory experiment and a numerical simulation were compared to validate the applicability of laboratory testing in rockfall assessment and calibrate the coefficient of restitution, which is a critical parameter in bouncing blocks. Results indicated that steep slopes and hard ground surfaces cause a high bounce height of falling rocks. Moreover, light rocks bounce higher than heavy rocks, and rocks with round shapes bounce high initially and then roll further away from the falling slope. Therefore, the influence of rock sizes and shapes and impact surface material must not be omitted in investigating rockfall protective measures.

Structure from motion (SfM) permits a fast and inexpensive way to obtain data necessary for geotechnical characterization of rock slope. Unlike scanline survey, a traditional technique, SfM can reduce the risk, time, cost, bias in measurement and improve the accessibility, quantity and quality of data collection. A small and low cost Unmanned Aerial Vehicle (UAV), DJI Phantom 4 Pro mounted with 20 megapixels camera is utilized to capture high quality images in this study with Real-Time Kinematic Global Positioning System (RTK-GPS) being used to obtain coordinates of 10 Ground Control Points (GCP) distributed evenly on the rock slope. Images registered and aligned with GCP render better accuracy results compared to images aligned without GCP. With photogrammetry software, dense point cloud, digital surface model (DSM) and orthophotos can be generated. 3D dense cloud reconstructed in the setting of high accuracy, with millions of points of a rock surface, can be imported into CloudCompare to extract the geological planes using FACET plugin. The major discontinuity sets can be observed and the orientation (dip/dip direction) of the discontinuity sets obtained from the algorithm is accurate and reliable for future geotechnical work such as rock slope stability analysis.

Unmanned Aerial Vehicles (UAV) photogrammetry is as precise as conventional survey which able to produce centimetre accuracy. It is considerably quicker and gives brief portrayal of geography. Given ideal regulatory conditions this innovation will supersede current techniques for most mapping and studying applications. UAV can be an important technology to extract useful information of the earth surface in short period of time for example Digital Surface Models (DSM) and other information. The final products are highly dependent on the choice of values on various parameter for the flight planning, and for the processing of the data. The aim of this research is to study the effect of Ground Control Point (GCP) influence on the final accuracy of the output with difference flying altitude. All photogrammetric procedure was applied using Agisoft PhotoScan a Structure from motion (Sfm) software from aligning photos to build Digital Elevation Model (DEM) and georeferenced orthophoto. In this research, we have used total of 16 GCP's where the coordinates measured with L1 RTK GPS receiver. Analysis was carried out to show the importance of GCP for mapping using low cost UAV. The analysis of both qualitative and quantitative were carried out to verify that the use of GCP is essential to produce a centimetre accuracy photogrammetric output. Utilization of GCP in mapping is significant because the output obtained from photogrammetry comes with actual measurements of the model that we have mapped.