Applications Of Vilocity Tomography In Experimental Study On Seepage Diagnose Of Earth-rock Fill Dams

Seepage failure is one of main causes of earth-rock fill dams'collapse. the property of seepage alleys such as location, size and figure should be ensured to deal with this problem.Therefor ,rely on the NSFC project Study on earth-rock dams'seepage diagnose with coupled waves and electricity tomography technique, the software package is developed based on forward and inversion method of ray tomography technique. Its reliability is verified with numerical model experiment. Finally ,the vilocity tomography technique is used in making expriment researchs on seepage failure model of earth-rock dam to explore seepage alley in impermeable wall and lower reaches of dam .the main points are briefly sunnarized as follows:i) Based on shortest path ray tracing technique with the plane elastic theory and LSQR, the forward model and the inversion model of seepage diagnoses technique of earth-rock dam is developed.ii)The software package with friendly interface and convenient use of vilocity tomogranphy technique is developed by mixed-languuage programming with VB6.0 and Fortran6.6. program of the model discretization, the velocity initialization,the forward model,the inversion model, the error analysis and the data inputing and outputing are accomplished. The graphic datas were processde by software of surfer8.0.iii)Three numerical models with abnormal velocity area are built, results of numerical model's calculation and error analysis indicates that the vilocity tomography technique and the software package are reliable and feasible.iv)Earth-rock fill dam models with two different seepage forms are made ,and the software package has been emloyed for defects exploration to make a vilocity tomography diagnosis for seepage alley in impermeable wall and lower reaches of the dam models.The effects of seepage alley and seepage upon elastic wave velocity are analysed and discussed at last.