This paper proposes a method for determining the mechanical properties (Young's modulus, Poisson's ratio, yield strength, and work hardening factor) of a material at a specific point using an indentation technique that utilizes a specially designed indenter in conjunction with an inverse problem and finite element analyses. The specially designed indenter combines the characteristics of spherical and conical indenters and can be used to produce multiple indentations at a single point. The feasibility of the proposed method for determining the local mechanical properties of a material was confirmed by detailed precision verifications in the ideal case and the worst case.

A series of forced vibration tests were conducted on a proto-type pile foundation which is built in the Tainan Science-Based Industrial Park and is modeled on the foundation type of Taiwan High Speed Rail. The test method, analysis procedure and results of test are briefly introduced in this paper. Besides, a finite element method by using the computer program ABAQUS is used to simulate the test. Results obtained are in good agreement with the results of in-situ test, and both are helpful for understanding the characteristics of the ground responses of the site and for identification of the soil-structure interaction of Taiwan High Speed Rail foundation system.