Role of Floods on Sinkhole Occurrence in Covered Karst Terrains: Case Study of the Orléans Area (France) During the 2016 Meteorological Event and Perspectives for other Karst Environments

Abstract

In parallel, an innovative internal erosion numerical modeling approach, based on Discrete Element-DEM and Lattice Boltzmann methods-LBM, has been developed through a partnership between the French Geological Survey (BRGM) and the Environment and Agriculture National Research Institute (IRSTEA). The upward propagation of cavities within the cover were successfully simulated. The role of different parameters (soft cover cohesion, hydraulic head, system geometry, etc.) in the sinkhole occurrence were tested by a parametric analysis.

A reactivated cave system induces rapidly developing cover-collapse sinkholes in Tasmania, Australia

“…Cover-collapse sinkholes are particularly common in areas where more cohesive layers overlie less consolidated deposits (Tharp, 1999) and in areas like the Railton valley where thick deposits (usually sedimentary) mantle karst (Noury et al, 2018;Intrieri et al, 2018). Langer (2001) cited several studies that showed that cover-collapse sinkholes were most likely to form when the water table first declines past the bedrock/soil contact in areas where the unconsolidated sediments overlying limestone are 5-30 m thick as in the Railton area, although other factors like the nature of the clay fraction in the sediments also influence the risk of sinkhole forming.…”

“…Water under pressure may liquify clay in overburden deposits above the karst contact, thereby undercutting the ground surface until roof failure occurs (Jia et al, 2018;Soliman et al 2018). Examples of cover-collapse sinkholes forming rapidly after heavy rain have been documented in Europe (Gutiérrez-Santolalla, 2005;Martinotti et al, 2017;Noury et al, 2018;Parise et al, 2018), the US (Hyatt and Jacobs, 1996;Hunt et al, 2013), and in the Mole Creek karst of northern Tasmania (Slee et al, 2019).…”

Discharge rate characterization for submerged grains flowing through a hopper using DEM-LBM simulations

“…Though dry grains discharge is rather well predicted, the potential behavior change when adding interstitial liquid, from partially to fully saturated situation, was much less studied. Nevertheless, the submerged granular flows are significantly encountered in geophysical processes such as soil subsidence after floods, which may occurs with increasing frequency due to climate changes [7,8,9]. In the case of intense rainfall, karst cover soils turn out to be one of the most critical environments for sinkhole occurrence [10,11].…”