Abstract

Sinkholes are a common geohazard in karst areas that can threaten human life and causes significant damage to infrastructure. Approximately 18% of the United States falls into karst area where overburden soils are underlain by soluble carbonate rocks. In Florida, sinkhole-related insurance claims between 2006 and the third quarter of 2010 amounted to $1.4 billion according to the Florida Office of Insurance Regulation. Effective methods and tools for the sinkhole detection and characterization are necessary. Numerical analysis can play an important role in determining the stability of sinkholes and understanding the failure mechanism under varied subsurface geological conditions. In this study, the geomechanical behavior of sinkholes due to subsurface cavity and its expansion was numerically investigated by Plaxis 2D finite element (FE) software. The study investigated the effects of embedded clay layers on the failure mechanism of cover-collapse sinkholes. Selected sinkhole case histories (including Winter Park sinkhole) from different locations in Florida are also presented. Soil profiles and parameter values were determined using subsurface exploration data and published correlations in the geotechnical literature. Appropriate constitutive models were employed in the numerical simulations to reproduce the soil behavior that can account for small strain stiffness, soil nonlinearity, recent stress history effects, and large-strain asymptotic behavior. The constitutive models that were adopted in this study were elastoplastic models (Hardening Soil Small Strain model) and critical state models (hypoplasticity models) for sands and clays. Induced stress paths due to an evolving subsurface cavity were compared versus the yielding characteristics of different soil types. Induced ground settlements, distortions and influence zones due to an evolving subsurface cavity in the numerical environment were computed and compared versus the damage criteria of infrastructure in engineering practice. Based on a series of FE simulations, site-specific stability charts of selected sinkhole sites in Florida were developed using shear strength reduction techniques. The aim of this chart is to be used as a preliminary check of the sinkhole stability in the study domain, i.e. central Florida, at similar subsurface conditions.

Notes

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Graduation Date

2020

Semester

Summer

Advisor

Nam, Boo Hyun

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Civil, Environmental, and Construction Engineering

Degree Program

Civil Engineering

Format

application/pdf

Identifier

CFE0008244

Language

English

Release Date

8-15-2023

Length of Campus-only Access

3 years

Access Status

Doctoral Dissertation (Campus-only Access)

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