Weak foliated rock slope stability analysis with ultra-close-range terrestrial digital photogrammetry Alameda-Hernández, Pedro El Hamdouni, Rachid Irigaray, Clemente Chacón, José Terrestrial digital photogrammetry Slope Mass Rating Schistosity Weak rocks Sampling bias SMR Este artículo ha sido financiado por el Grupo de Investigaciones Medioambientales: Riesgos Geológicos e Ingeniería del Terreno (RNM121) de la Junta de Andalucía y por proyecto de investigación "Desarrollo de técnicas para la regionalización de la peligrosidad de movimientos de ladera en la cuenca del río Genil y la cuenca Sur (Adra-Nerja) de la Cordillera Bética" (Ministerio de Educación y Ciencia del Gobierno de España). This paper presents a review of the data acquisition procedures of geotechnical parameters for rock slope stability assessment and the proposal of some new improvements. For this purpose, a piece of research based on the slope mass rating classification system using closerange terrestrial digital photogrammetry (CR-TDP) has led to improvements in quality and timing of discontinuity data acquisition, and analyzes the suitability of each one of the parameters when applied to weak foliated rocks. TDP allows rapid 3D image acquisition of a rock slope, which can be analyzed using software to determine the geometrical parameters that affect stability. A fast procedure to perform the photogrammetric, non-contact survey in order to obtain the 3D images is shown in this paper. Being a rapid and single-person task, this procedure provides enough precision to be applied to weak foliated rock slopes with non-well-defined geometry. Furthermore, the study has focused on highly foliated rock outcrops, in which high resolution in the 3D images is very desirable. This research was applied to mountain road cuts, in which the use of TDP with a very close range was necessary. Through an application on weak rocks in the Alpujarras (Andalusia, Spain), this work analyzes the bias when applying TDP to materials such as these, under progressive weathering processes. 2023-12-22T13:52:06Z 2023-12-22T13:52:06Z 2019 journal article Published version: Alameda-Hernández, P., El Hamdouni, R., Irigaray, C. et al. Weak foliated rock slope stability analysis with ultra-close-range terrestrial digital photogrammetry. Bull Eng Geol Environ 78, 1157–1171 (2019). [https://doi.org/10.1007/s10064-017-1119-z] https://hdl.handle.net/10481/86445 10.1007/s10064-017-1119-z eng open access Springer Nature