Experimental study on water and sand inrush of mining cracks in loose layers with different clay contents

Abstract

Water and sand inrush is one of the many disasters in mining operations in Western China and is closely linked to the characteristics of loose layers. Therefore, it is very important to study the mechanism of water and sand inrush under different loose layer conditions for recognizing and preventing water and sand inrush. In this article, a mechanical model of water and sand inrush was established, and the limit equilibrium conditions of water and sand inrush under different clay contents in the loose layer were studied. On this basis, physical experiments of water and sand inrush through loose layers with different clay contents were carried out. The results showed that both the 5 and 10% clay contents in the loose layer promoted the occurrence of water and sand inrush. However, compared with that of the 5% clay content, the possibility of water and sand inrush was weakened under the condition of 10% clay content. When the clay content was 20%, the sand body remained stable, inhibiting the occurrence of water and sand inrush. After the test, “collapse pits” were observed on the upper surfaces of the loose layers with 0, 5 and 10% clay contents. However, the upper surface of the loose layer with 20% clay content had only a small depression, and no collapse pit was observed. The results of this study provide experimental guidance for research on water and sand inrush of mining-induced cracks in loose layers with different clay contents.