Case studies are put forward on a high arch dam, and the fusion entropy is calculated according to the monitoring data from strain gauges. Meanwhile, the catastrophe theory is used as the variation criterion of an entropy sequence in order to predict the instability time of dam cracks. Through the weighted linear fusion method, the entropy of multiple monitoring points is obtained for analyzing the behavior of dam cracks in the selected zones. To solve this problem, the influence of spatial positions of monitoring points on inspection zones is represented by a weight index, and the weight index is determined by the distance measure method proposed in this paper. Due to the randomness and locality of crack propagation, it is difficult to predict the location of cracks by traditional monitoring methods. Therefore, the entropy theory can be used in analyzing the behavior of dam cracks. The propagation of cracks in concrete dams is accompanied by changes in energy distribution, which can be represented by changes in the structure’s system entropy. Therefore, in order to ensure the stability of LCPTS at high temperature, the crack status should be closely monitored.The integrity and safety of concrete dams are seriously affected by the existing cracks in dam bodies, and some serious cracks may cause dam failure or disaster. For track slabs with a crack spacing of less than 5 m, the vertical displacement will be affected by adjacent cracks. Oblique non-penetrating cracks with an angle less than 45° were found not to affect the vertical deformation, while penetrating cracks with an angle less than 35° did not lead to yielding of the reinforcing bars or affect the normal operation of track structures.

Cracks of depth 15 cm are most likely to cause track slab up-warp. The results showed that ∧-shaped cracks can make track slabs suffer an up-warp deformation with an angle at the apex, while ∨-shaped cracks will cause track slabs to have two peaks at both sides of the crack.

The effects of crack status on the stability of track slabs under the action of a temperature rise were studied through simulations. Through analysing the stress and deformation of a longitudinally coupled prefabricated track slab (LCPTS) with cracks at high temperature, an analysis model for the stability of LCPTS with cracks was established based on the finite-element method and was tested by a scale model on-site.

Crack status