Visual measurement of pile movements for the foundation work using a high-speed line-scan camera

When a construction company builds a high structure, many piles should be driven into the ground by a hammer whose weight is typically 7000 kg in order to make the ground under the structure safe and strong. It is essential to determine whether a pile is penetrated into the ground enough to support the weight of the structure since ground characteristics at different locations are different from each other. In order to measure the pile movements, a specially designed mark is designed and a high-speed line-scan camera is used in this paper. A mark, in which black and white right-angled triangles are stacked, is used for the measurements of movement information for vertical distances, horizontal distances and rotational angles simultaneously. The measurement performance of dynamic characteristics of the pile at impact instant is improved dramatically compared with the equipment using speckle laser sensors. The developed visual measurement system is successfully applied for a real penetration measurement system for building construction.