Laboratory Study and Analysis on the Effect of Internal Water Pressure on the Karstic Rocks Stress Conditions


Omid Azadegan

Ph.D. student of Geotechnical Engineering
Shahid Bahonar University of Kerman, Iran

G.R Pourebrahim

Assist. Professor, Faculty of Civil Engineering Dept.
Shahid Bahonar University of Kerman, Iran.



When any changes impose to water table and internal water pressure of karstic areas which act as water aquifers and underground reservoirs, some problems like instability, general collapses, giant settlements and many other phenomena would happen due to the karstic rock masses failure. Therefore, analysis of internal stresses in rock masses in such cases would be really helpful in preventing any disasters. This study has considered the analysis of internal compressive, tensile and shear stresses of a rock cubic element comprising an elliptical hollow with internal hydrostatic pressure. Then, in order to clarify the effect of water pressure inside the karstic hollows, a simplified model has been carefully analyzed and a laboratory simulation has been performed on analyzed model.
The study results show that reduction of internal water pressure would lead to decrement in bearing capacity and compressive strength of rock masses with hollows. On the other hand, if the internal pressure increases the amount of tensions would also improve and may lead to tensile failure and progression of cracks in rock masses.

Keywords: compressive stress, shear stress, elliptical hollows, the uniformity pressure.

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