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Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study

Rawal, Kishor
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1480069621108946

Abstract Details

2016, Master of Science, University of Toledo, Civil Engineering.
The motivation of this research originates from the hypothesis that the sinkhole occurrences in the karst areas are significantly affected by the mechanical behavior of geomaterials, chemical dissolution, hydrological transport and scenarios. The development and formation of sinkholes is strongly dominated by the geo-mechanical characteristics of soil and rock behavior complicated by the chemical interaction and hydraulic transport processes. Sinkholes formed in soils can be sudden and catastrophic in nature and involve many intricate processes which have not yet been assessed properly. This thesis presents preliminary results of an ongoing research focusing on mechanical and coupled hydro-mechanical modelling approaches, aimed to understand the diverse and intricate mechanisms behind the formation and development of cover-collapse and cover-subsidence types of sinkholes. The feasibility of the geomechanics approach of the sinkholes, understanding the critical factors and mechanisms involved in the formation of sinkholes and their deformation characteristics has been assessed using FLAC 2D. First, a parametric study was conducted in order to examine the effects of shape and size of the cavity, overburden thickness and pressure related to vertical stress and deformation. Larger sizes of the cavity and higher overburden pressures cause higher deformation at the cavity resulting in sinkhole development. Similarly, shape of the cavity is also an influential factor inducing sinkhole formation. Circular cavities are found more stable than the square and rectangular cavities. Second, the FLAC was also used to model the behavior of geomaterials around a cavity in various potential water drawdown scenarios. Deeper lowering of the water table was found to cause larger deformation. Moreover, the influence of the slow and rapid drawdown of the water is studied thoroughly, the results show that the rapid drawdown induces fast creation of sinkholes. However, slow drawdown has little effect on development of sinkhole. In addition, a parametric study was conducted focusing on the effect of cohesion, permeability and ground water flow time on the deformation characteristics of sinkholes and ground subsidence. Overall, the results presented in this thesis show some key characteristics of sinkhole development and collapse, and demonstrate the feasibility of a numerical modelling approach capable of exploring many intricacies and complexities involved in the mechanisms of the cavity growth and propagation.
Liangbo Hu (Committee Chair)
Brian W. Randolph (Committee Member)
Eddie Chou (Committee Member)
96 p.
Civil Engineering
FLAC; Simulation; Overburden; drawdown; Geo-mechanical; Hydrological; Hydro-mechanical; FISH

Recommended Citations

Citations

  • Rawal, K. (2016). Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1480069621108946

    APA Style (7th edition)

  • Rawal, Kishor. Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study. 2016. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1480069621108946.

    MLA Style (8th edition)

  • Rawal, Kishor. "Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study." Master's thesis, University of Toledo, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1480069621108946

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Toledo and OhioLINK.