Influential factors on surface subsidence in stripe mining under thick unconsolidated layers and thin bedrock

To study the influence rule of mining rate, mining width, bedrock thickness, loose rock thickness and exploiting thickness on surface subsidence, a numerical model was established based on FLAC3D, and the influence rule of the above five factors on the maximum surface subsidence and subsidence coefficient was investigated through simulating the surface movement deformation by changing the above factors respectively. These five factors were sorted out according to their importance degree through orthogonal experiment, and their descending order concerning correlation to the maximum subsidence and subsidence coefficient has been obtained: mining rate, bedrock thickness, loose rock thickness, mining width, and exploiting thickness. With the results of numerical simulation, the comprehensive function expression between the maximum surface subsidence and these five factors was obtained by regression fitting on MATLAB mathematical software. At last, the surface subsidence in stripe mining under thick unconsolidated layers and thin bedrock in certain coal mines in China was predicted according to the expression; the expected and measured results showed that this expression had a high credibility. © 2016, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.