DEVELOPMENT EQUATION FOR DETERMINATION THE START TIME OF SEEPAGE UNDER HYDRAULIC STRUCTURE RESTING ON SOIL CONTAINING A CAVITY

This study aims to introduce a formula for determination the start time of seepage when single cavity presence at a specific location within the homogenous soil under a hydraulic structure. The investigation aims to observe the effect of cavity locations and size on the start time of seepage. The experimental work has been done in three stages, the first stage includes 36 models of 75mm in diameter cavity, while the second and the third stages includes eight models for each with 100mm and 34mm diameter of cavity respectively. The analysis of result shows that, generally, the effect of cavity was positive in term of increasing the time of starting the seepage. To generate the deterministic formula the SPSS statistical software was used and the results of multiple regressions are checked by statistical indices. By this process more realistic formula has been proposed with acceptable reliability.