A numerical investigation into sinkhole formation

Keightley, Anthony J (2016) A numerical investigation into sinkhole formation. [USQ Project]

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Abstract

Sinkholes pose danger to the environment through the associated gradual subsidence or sudden collapse of the ground that can lead to loss of lives and damage to property. Sinkholes develop in different sizes, shapes and rates all over the world. This project assists in further understanding how sinkhole development can be analysed through analytical theories and the application of numerical methods to create simulations. It involves the investigation, development and verification of numerical models aimed at determining the slope stability of differing trapdoor scenarios. The analysis will be completed through using the computer program Fast Lagrangian Analysis of Continua (FLAC). The completion of 2D numerical models gives the chance to simulate many different sinkholes, with varying material properties and different overburden depth to cavity width and length ratios.

Sinkholes are analysed by strength reduction method, producing the factor of safety of the overburden above a trapdoor. The numerical study appraised sinkhole propagation with the Fast Lagrangian Analysis of Continua software to determine the slope stability of differing trapdoor scenarios. This furthered the understanding of sinkhole mechanics by providing a more realistic model in relation to an actual sinkhole formation. The extent of surface failure was investigated and found to be dependent upon the depth ratio of the sinkholes trapdoor.

The many varying cases with regards to surcharge pressure and internal pressure within the cavity where tested to determine to what extent the pressure ratio affected the resulting sinkhole formed under these varying pressure conditions. Scenarios were initially tested with zero pressure ratios and then rerun with both positive and negative pressure ratios to simulate both collapse failure as well as blowout of the sinkhole.

Stability Charts were developed for both the zero pressure ratio and non-zero pressure ratio scenarios and possible practical applications demonstrated to allow for quick ascertainment of conditions and the associated factor of safety or critical conditions.


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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor or Engineering (Honours-Civil) project
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Supervisors: Shiau, Jim
Date Deposited: 06 Jun 2016 23:25
Last Modified: 06 Jun 2016 23:25
Uncontrolled Keywords: Sinkhole, Stability, Trapdoor, Modelling
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090599 Civil Engineering not elsewhere classified
URI: http://eprints.usq.edu.au/id/eprint/29260

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