Distribution and measurement method and device for improving measurement precision of internal shrinkage amount of prestressed tendon

The invention relates to the technical field of constructional engineering quality detection, and provides a distribution and measurement method for improving the measurement precision of the internal shrinkage amount of a prestressed tendon, which comprises seven steps from S1 to S7. The invention further provides a device for measuring the internal shrinkage amount of the prestressed tendon. According to the invention, through a to-be-measured plane formed by a magnet and an arch-shaped steel leveling ruler, the deformation condition of the deformation surface can be accurately and simply reflected, and only four measurement values need to be completed, so that the measurement can be rapidly completed. The to-be-measured plane is a measurement position which does not shift and does not need to be marked or memorized, and inaccurate measurement values caused by position changes of measurement points during multiple times of measurement are avoided. The steel leveling ruler is used for leading out a point to