Abstract: A method of constructing foundation piles provides improved hole stability and bearing characteristics. A boring a hole is initially formed by drilling. A horizontal pressure is then applied to the inner walls of the hole over a vertical portion of predetermined height until a desired degree of compression is attained. Horizontal pressure is then applied over a subsequent vertical portion of an inner circumferential surface of the hole vertically adjacent to a vertical portion pressed in a preceding step of applying horizontal pressure. The steps of compression are continued until a contiguous vertical expanse of the hole is compressed to a desired degree. Alternatively, the depth of the hole may be increased sequentially following a compression operation, and the subsequently formed hole depth then horizontally compressed.

Abstract: A method of determining capability and quality of a foundation pile and a method of designing the foundation pile comprises the following steps: positioning a ground charcteristics analyzer in a bored hole where the foundation pile is constructed; displacing the surrounding ground of the bored hole; and measuring the force applied to a bored hole and the induced displacement; so that the characteristics and quality of soil and the pile can be analyzed simultaneously with executing the construction. A ground characteristics analyzer with which the above-mentioned methods are performed comprises a horizontal pressing device which protrudes in the radial direction from the outer peripheral of the body of the analyzer to displace the surrounding ground of a bored hole and a vertical depressing device which protrudes downward to deform the bottom ground of the bored hole.

Abstract: A method of determining capability and quality of a foundation pile and a method of designing the foundation pile comprises the following steps: positioning a ground characteristics analyzer in a bored hole where the foundation pile is constructed; displacing the surrounding ground of the bored hole; and measuring the force applied to a bored hole and the induced displacement; so that the characteristics and quality of soil and the pile can be analyzed simultaneously with executing the construction. A ground characteristics analyzer with which the above-mentioned methods are performed comprises a horizontal pressing device which protrudes in the radial direction from the outer peripheral of the body of the analyzer to displace the surrounding ground of a bored hole and a vertical depressing device which protrudes downward to deform the bottom ground of the bored hole.