Experimental study on failure law of cracking and disintegration of rock mass in large-scale slope

The process of instability and failure of slope rock mass include cracking,through,disintegration,slipping.But capturing the variation and characteristics of surface deformation and deep sliding surface mechanical in each session is the key to explore the landslide monitoring and early warning guidelines.In this paper,“Constant Resistance Large Deformation Cable (NPR) deep sliding force automatic monitoring system and surface displacement monitoring system”has been applied in Nanfen open-pit iron mine stope footwall to carry out field physical simulation experiment of landslide induced by artificial excavation.It aims to explore the disintegration of slope rock mass crack damage and the variation and time effects of deep sliding force before and after the landslide.The results show that due to the effect of artificial excavation disturbance,the time of slope rock mass surface cracks is lagging behind the deep sliding force mutation time; that is,when the sliding force fell sharply after 4 h,the slope surface rock mass initial cracking was 6 mm(length 200 cm ); when the sliding force fell sharply after 96 h,the surface rock mass crack width was 74 mm(length 1306 cm ); when the sliding force fell sharply after 168 h,the sliding slope collapsed completely.It proved that the duration of this type of slope from the deep mechanical imbalance to the failure of slope surface disintegration is at least 7 days,and also the results provide a scientific basis for the establishment of monitoring and early warning rule of sliding force in this region.