Showing papers by "Jacques Locat published in 2015"
TL;DR: In this paper, an experimental study of the rheological behavior of clay-rich soils (i.e., Mediterranean Sea and bentonite clays) and clay-poor material (e.g., iron mine tailings) that includes steady state, dynamic response, and hysteresis measurement was performed.
29 citations
TL;DR: In this article, the evolution of different channels present in Wabush Lake and their link with knickpoints found at the head of most of these channels are studied, which is the process responsible for the creation of erosional channels.
Abstract: Since 1964, the Iron Ore Company of Canada has deposited iron tailings resulting from mining operations into Wabush Lake, Western Labrador, Canada. This activity has resulted in a continuous hyperpycnal flow flowing over the lake floor. Bathymetric surveys were carried out between 1999 and 2008 as part of the overall environmental Iron Ore Company of Canada plans to maintain safe disposal strategies of tailings into the lake. Here, this dataset is used to study the evolution of different channels present in Wabush Lake and their link with knickpoints found at the head of most of these channels. The channels show notable evolution from one survey to the next. Some knickpoints and channels may be followed throughout more than one survey; the evolution of these knickpoints is the process responsible for the creation of erosional channels. The context in which they appear, as well as the evolution of some of the subaqueous channels is analysed. Cyclic steps and sediment waves are also found in the lake. These rhythmic bedforms, also created by the passage of turbidity currents, are analysed. Sediment waves found in Wabush Lake show values for both wavelength and wave height that are approximately one order of magnitude smaller than most of those found in the marine environment.
20 citations
TL;DR: In this paper, the authors presented and analyzed combined in-situ and satellite-based monitoring data to interpret the kinematic behavior of the slide and the evolution of the rockslide and the possible mechanisms that can lead to an accelerating phase of movement.
17 citations
TL;DR: The First International Workshop on Warning Criteria for Active Slides (IWWCAS) was organized to promote sharing and networking among members from specialized institutions and relevant experts of EWS to stimulate discussion and collaboration between organizations dealing with the complex task of managing hazard and risk related to active slides.
Abstract: Early warning systems (EWSs) rely on the capacity to forecast a dangerous event with a certain amount of advance by defining warning criteria on which the safety of the population will depend. Monitoring of landslides is facilitated by new technologies, decreasing prices and easier data processing. At the same time, predicting the onset of a rapid failure or the sudden transition from slow to rapid failure and subsequent collapse, and its consequences is challenging for scientists that must deal with uncertainties and have limited tools to do so. Furthermore, EWS and warning criteria are becoming more and more a subject of concern between technical experts, researchers, stakeholders and decision makers responsible for the activation, enforcement and approval of civil protection actions. EWSs imply also a sharing of responsibilities which is often averted by technical staff, managers of technical offices and governing institutions. We organized the First International Workshop on Warning Criteria for Active Slides (IWWCAS) to promote sharing and networking among members from specialized institutions and relevant experts of EWS. In this paper, we summarize the event to stimulate discussion and collaboration between organizations dealing with the complex task of managing hazard and risk related to active slides.
11 citations
TL;DR: In this paper, the authors used multibeam bathymetric surveys of Wabush Lake to determine the evolution through time of this anthropic source-to-sink system, from the point where sediments exit the slurry pipelines at the head of the system to the distal end and bottom of the Lake.
6 citations
TL;DR: In this article, the authors examined the geotechnical and rheological characteristics in terms of the transition from slide to flow in submarine landslides and found that the sudden reduction in shear strength varied between about 300 and 800Pa (Δw ǫ = 2-20%).
Abstract: This paper examines the geotechnical and rheological characteristics in terms of the transition from slide to flow in submarine landslides. This paper contains the results of a series of laboratory tests on the Saguenay Fjord fine-grained sediments. There are two types of tests: (1) vane shear tests in which intact and remolded samples are sheared and exposed to ambient water and (2) rheological tests performed on remolded sediment (with variable liquidity index) using a viscometer. The results explain the effect of water infiltration into soil. The sudden reduction in shear strength varied between about 300 and 800 Pa (Δw = 2–20%). The viscosity obtained from normalized flow curves (i.e., the logarithmic plot of shear stress versus the shear rate) were employed to characterize the rheology of soil. The mean value of viscosity (strength parameter in this case) as a function of shear rate from the results of fine-grained sediments varied between about 0.1 and 0.4. The values of yield stress and viscosity t...
3 citations