Publication Date
4-1-2018
Abstract
The behavior of cover-collapse sinkholes in Central Florida was investigated in this research by both physical and numerical methods. In the physical model, a head drop between the unconfined aquifer and the confined aquifer was applied, and the cavity propagation due to a fracture at the boundary between the two aquifers was visually monitored. The cavity grew upwards in an inverted triangle shape until ground surface collapse occurred. The same cavity shape was then incorporated into the numerical study. A stress-seepage coupled analysis was carried out using GeoStudio modules: SEEP/W and SIGMA/W, simultaneously. The stress conditions during sinkhole formation were assessed at different groundwater conditions and cavity sizes. Stress redistributions were observed around the cavity due to soil arching. The effective stress significantly increases at the corners of the cavity to compensate for a stress reduction above the center of the cavity. Highest recharge values and seepage forces occur around the cavity corners. The stress paths at the corners show that the stability decreases when the cavity height increases, even when the overburden thickness decreases. Additionally, the side angles of the cavity affect the stress conditions around it.
Rights Information
DOI
https://doi.org/10.5038/9780991000982.1040
Physical and Numerical Analysis on the Mechanical Behavior of Cover-collapse Sinkholes in Central Florida
The behavior of cover-collapse sinkholes in Central Florida was investigated in this research by both physical and numerical methods. In the physical model, a head drop between the unconfined aquifer and the confined aquifer was applied, and the cavity propagation due to a fracture at the boundary between the two aquifers was visually monitored. The cavity grew upwards in an inverted triangle shape until ground surface collapse occurred. The same cavity shape was then incorporated into the numerical study. A stress-seepage coupled analysis was carried out using GeoStudio modules: SEEP/W and SIGMA/W, simultaneously. The stress conditions during sinkhole formation were assessed at different groundwater conditions and cavity sizes. Stress redistributions were observed around the cavity due to soil arching. The effective stress significantly increases at the corners of the cavity to compensate for a stress reduction above the center of the cavity. Highest recharge values and seepage forces occur around the cavity corners. The stress paths at the corners show that the stability decreases when the cavity height increases, even when the overburden thickness decreases. Additionally, the side angles of the cavity affect the stress conditions around it.
