Publication Date
5-2020
Abstract
In September 2017, Hurricane Irma made landfall on the state of Florida. This extreme weather event produced an average of 20-40 centimeters of rainfall across the state. In the following weeks, at least 30 new sinkholes were reported throughout the affected area. An investigation of the sinkhole sites where openings occurred in the middle of a roadway, was carried-out. Multiple cone penetration tests (CPT) were performed at those collapsed sites. In this paper, a comprehensive case study of a sinkhole collapse is presented. First, a hydrogeological assessment on the sinkhole site was conducted. Second, CPT data were investigated. Particularly, a sinkhole evaluation index, the Sinkhole Resistance Ratio (SRR), was used to evaluate the sinkhole vulnerability in the collapsed site. Lastly, a finite element (FE) based analyses was employed to further investigate the effect of precipitation on sinkhole stability. The CPT results were used to estimate soil type and strength parameters as inputs to the FE model. Based on the results of multi-scenario simulations, it is believed that the main triggering mechanism in the US 441 site was a rapid increase of hydraulic gradient (or seepage velocity) that accelerated soil erosion and piping. In addition, the effect of raised groundwater table on the failure condition of overburden soil layer may not be significant.
Rights Information
DOI
https://doi.org/10.5038/9781733375313.1044
Sinkhole investigation after Hurricane Irma
In September 2017, Hurricane Irma made landfall on the state of Florida. This extreme weather event produced an average of 20-40 centimeters of rainfall across the state. In the following weeks, at least 30 new sinkholes were reported throughout the affected area. An investigation of the sinkhole sites where openings occurred in the middle of a roadway, was carried-out. Multiple cone penetration tests (CPT) were performed at those collapsed sites. In this paper, a comprehensive case study of a sinkhole collapse is presented. First, a hydrogeological assessment on the sinkhole site was conducted. Second, CPT data were investigated. Particularly, a sinkhole evaluation index, the Sinkhole Resistance Ratio (SRR), was used to evaluate the sinkhole vulnerability in the collapsed site. Lastly, a finite element (FE) based analyses was employed to further investigate the effect of precipitation on sinkhole stability. The CPT results were used to estimate soil type and strength parameters as inputs to the FE model. Based on the results of multi-scenario simulations, it is believed that the main triggering mechanism in the US 441 site was a rapid increase of hydraulic gradient (or seepage velocity) that accelerated soil erosion and piping. In addition, the effect of raised groundwater table on the failure condition of overburden soil layer may not be significant.
