Abstract:In the process of dinosaur fossil excavation, mechanical disturbance will directly lead to the fragmentation of fossils or surrounding rocks, and stress release will lead to the generation and expansion of surface cracks of fossils and surrounding rocks. These fractures will provide a channel for the movement of water and air, and make weathering damage more rapid. Based on the theory of layered excavation, a numerical model has been established to simulate the process of fossil excavation. Through computer simulation of the process of equivalent stress change and XZ direction stress change at the depths of 0m, 11m, 14m and 19m, the maximum equivalent stress difference on the suface of fossils before and after excavation is 0.34MPa, and the maximum equivalent stress difference on the surface of surrounding rocks is 0.3MPa. It is found that the more obvious the bullet phenomenon is, the more serious the stress release is. Although the shear stress on the surface of the fossils is small, its influence on the weathering of the fossil is much greater than that under the compressive stress condition, which is the main reason for the unloading cracks. Therefore, the excavation of dinosaur fossils should be slowly excavated layer by layer, so that the fossils gradually reach a new stress balance, so as to reduce the weathering damage caused by stress release to fossils, especially to do a good job of slope protection to prevent the generation of shear stress to the maximum extent.
