Novel Experimental Model to Investigate Fluid-Solid Coupling in Coal Seam Floor for Water Inrush

Fluid-solid coupling simulation experiment is an important method for studying water inrush from the coal seam floor. However, the experiment involves seepage-stress coupling problems, and most existing fluid-solid coupling model experiment systems do not meet sealing requirements. To address this issue and to successfully conduct the model experiment, a novel similitude experimental model with excellent sealing was developed for studying fluid-solid coupling during water inrush from the floor of the coal seam. Similitude relationships were also derived using mathematical models for fluid-solid coupling in homogeneous continuum media, and non-hydrophilic fluid-solid coupling similitude materials were prepared. Results show that the experimental system can be used to analyse the variation characteristics of the floor stress and the water pressure, and the mining-induced floor stresses can be divided into three distinct stages, such as the pre-mining stress-increasing stage, the post-mining stress-decreasing stage, and the stress recovery stage. The conclusions obtained in the study have important theoretical value to direct the similar engineering practice.