Falling behavior and application of interlayer-collapse-formed blocks during solution mining in salt cavern storages

During cavern leaching in layered salt rock of China，the falling blocks formed by interlayer collapse may collide with the leaching tubing. The falling blocks are deposited on the cavern bottom to form accumulation characteristics. Therefore，laboratory experiments of free-falling homogeneous aluminum blocks in water were carried out using photography，in order to study the free-falling motion behavior of typical interlayer blocks. Based on the repeated block-falling experiment ， distribution characteristics of block-falling points were preliminarily analyzed，and the probability of blocks colliding with the leaching tubing was qualitatively evaluated. The results show that：(1) The motion behavior of the free-falling block in still water can be divided into four types：steady falling，zigzag motion，tumbling motion and chaotic motion. (2) The motion behavior of free-falling blocks is greatly affected by its own geometric size ratio(such as length-to-width ratio，thickness-to-width ratio)，and is sensitive to initial conditions(such as initial angle). (3) For blocks with a thickness-to-width ratio of not more than 0.2 and a length-to- length ratio of not less than 2 falling in the cavern，there is a high probability of colliding with the leaching tubing. The research results may be expected to be applied to optimize the simulation software of cavern leaching，so that the shape prediction of salt caverns is more in line with the engineering reality，and the accident of leaching tubing broken by the block is reduced. © 2023 Academia Sinica. All rights reserved.