Search

The Valles Marineris canyon system in Mars shows large landslides across its walls, which can be 40 km wide and up to 60 km long, with fall scarps height as high as 7 km. These landslides were produced through a large mass movement at high speed by gravity across the trough floor. Although the triggering factors are unclear, several mechanisms have been proposed as, among others, large amounts of subsurface water, quake produced through normal faulting close to the canyon walls, and meteoritic impacts. In this work we examine the limit equilibrium slope stability of three landslides (placed respectively at Ius, Candor, and Melas Chasmata), which can be considered representative, with the aims of constraining their formation conditions. Our results suggest that external factors (as high pore fluid pressure, seismic loading or rock mass disturbance) do not seem necessary for the failure of slopes if they are composed of unconsolidated materials, while high pore water pressure or ground acceleration are needed to trigger slides in slopes composed of strong basaltic-like materials. Moreover, the presence of sub-surface ice would contribute to slope stability. As a whole, our findings point to ground shaking due to meteorite impacts as the main triggering force for most landslides in the Valles Marineris. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Engineering Geology & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cement stabilization of metallurgical residues is a frequently implemented option to reduce the associated environmental risks and thus simplify residue disposal procedures. As chemical stabilization is the first and main purpose of the process, physical testing of these stabilized residues is usually kept simple with unconfined compressive strength, permeability, and durability as the most frequently employed control tests. These tests are, however, unable to deliver a true image of the potentially complex mechanical behavior after stabilization of some important residues. One example is treated sludge. Stabilizing agents and fine residues are usually mixed at high water contents, resulting in a very porous microstructure, with fragile bonds. Under loading, rapid destructuration and compaction is possible and this process may be prone to material instabilities. These phenomena are experimentally and theoretically illustrated herein. The experimental illustrations are brought from a microstructural study and undrained triaxial campaign on a stabilized jarosite. The theoretical explanations are obtained from an elasto-plastic model previously employed for soft rocks. [ABSTRACT FROM AUTHOR]