These days we broadly apply drilled concrete piles for deep foundations to build nation's infrastructures. The defects of the deep foundations cause the decrease of their support load capacity and the increase of settlement, and the subsequent damage of the super-structures. In consequence, non-destructive testing techniques of concrete piles become important for their integrity evaluation.
To improve understanding and reliable application of the impact echo method for the integrity evaluation of the drilled concrete piles, numerical studies of the impact response of concrete piles using axi-symmetric three-dimensional finite element method are performed for (a) sound piles; (b) piles containing necks, voids and layers of low-quality concrete; and (c) piles in soil and/or above rock. Laboratory studies of concrete piles which are sound or contain necks and weak concrete layers at known locations are carried out to verify the finite element models.
The results of these studies show the feasibility of using impact echo method for the integrity evaluation of concrete piles. The numerical studies also show that the finite element method is effective for evaluating the impact response of drilled concrete piles, and the usefulness of finite element model is verified by comparing the results with laboratory impact echo test results of concrete shafts.
