Height deviation detection of rail bearing platform on high-speed railway track slab based on digital image correlation

The security and convenience of high-speed railways depend on the high reliability and high stability of bal-lastless tracks. To ensure track regularity, it is necessary to measure the height deviation of each rail bearing platform before laying the steel rail. By adjusting the fastening system, the rail could reach the design height and be at the same level. Conventionally, the height deviation of the bearing platform is measured through the contact walking measurement system. However, there are shortcomings such as few measurement points, long preparation time and low efficiency. In this paper, a fusion measurement method based on digital image corre-lation method and total station is proposed to solve these shortcomings. A measuring equipment consisting of dual cameras and reflecting prisms is assembled to measure the height deviation of bearing platforms (675 mm x 275 mm x 28 mm) on the high-speed railway track slab (5600 mm x 2500 mm). The three-dimensional contour of each bearing platform is measured using three-dimensional digital image correlation method and unified by locating the position of the reflecting prisms using the total station. In real applications, the height deviation of each bearing platform is measured with high accuracy, the contour measurement accuracy of a single bearing platform is better than 0.1 mm. More importantly, the range of ballastless tracks with bearing platforms to be detected in a single day is increased from the original 500 m to 5000 m without increasing the measurement error. The efficiency is increased by 10 times. The paper achieved the height deviation detection of rail bearing platform with high precision and high efficiency, contributing to improving the construction efficiency.