Abstract:
Sinkholes can occur on land underlain by dolomite and cause substantial damage to buildings and even loss of
life. More than four million people work or reside on dolomite land in South Africa and it is therefore important
to be able to construct safely on dolomite land and to minimise the risk of damage to infrastructure and loss of
life. Compacted soil mattresses are often used to found structures on areas underlain by dolomite. This study
investigated the effect of tensile reinforcement on the behaviour of a soil mattress spanning an underlying water
filled cavity designed to impose a cover subsidence sinkhole. Three small-scale models, each consisting of a soil
mattress with a cover subsidence sinkhole forming underneath, were constructed and tested in a geotechnical
centrifuge. In the first test, an unreinforced soil mattress was tested and in two more tests, reinforced soil
mattresses with different reinforcement strengths were tested. The settlement of the unreinforced soil mattress
was initially less than that of the reinforced soil mattresses up to the point at which it failed suddenly. Neither of
the reinforced soil mattresses failed suddenly, but both experienced large surface settlements that would have led
to substantial damage to an overhead structure.
