A Study On Failure Mechanism And Stability Of High And Steep Rock Slope In The Open Pit Of Daye Iron Mine

The east open-pit in Daye iron mine has complicated geological structure and developed fault joints. Since the last 50 years excavation, east open-pit has formed a rare crack rock high and steep slope at home and abroad.After 2005 it was transferred to underground mining, the northern slope of open-pit often occurs within the scale ranging from landslides and geological disasters. According to incomplete statistics, from 1972 to date, high and steep slopes of the slump-disaster that occurred in the East open pit achieve 20 times, and particularly in the F25 fault on both sides there are 11.It seriously affects the safety of mining personnel and equipment Therefore the research of slope deformation and failure mechanism about the high steep rock in the east open-pit of Daye iron mine has important significance in the prevention of geological disasters and the design of mine geological hazard emergency rescue system.This paper combines the actual project situation of the east open-pit in Daye iron mine. On the basis of the analysis of rock mass structural characteristics in the eastern open pit in Daye iron mine, and taking a typical slope section as example, this paper has a research on rock slope deformation and failure mechanism in the area, and meanwhile analyzes current slope stability. The main thesis and conclusions of the study are mainly the following points:(1) Research of regional engineering geology environmental. Mainly it includes studies about regional rock formation, structural styles and magma activities. It focuses onâ…¡area of Xiang bi hill on the East open pit in order to provide the basis for studies of the engineering geological characteristics and the numerical simulation about structural analysis of slope deformation and failure mechanism. (2) The analysis of the rock structural features in the mine. Focus will be on the investigation of open-pit rock group division and structural characteristics of rock mass in order to analyze characteristics of rock structure, the rock properties, faults construction, and joints construction in the east field of open-pit mining. It mainly includes material composition of the F25-fault slip-band landslide, and deformation characteristics.(3) Failure mechanism of high and steep slope inâ…¡areaFirst of all, from the perspective of geometry, on the basis of investigation and studies about slope characteristics of landslide zone, this paper uses stereographic projection analyzes rock mass structure of the area and slope, and last, combining history, establishes the three-dimensional geological model of the slope, and uses numerical simulation software to calculate the stress and strain on the slope after excavation, focusing on the simulation processes of a progressive breakdown of rock and the dynamic evolution of the instability on the surface structure under the conditions of the release of stress. It simulates the excavation to +108m,+60m,+36m,+18m level of the slope, including maximum principal stress, minimum principal stress, shear stress and plastic zone distribution.Simulation results show that as the excavation depth increases, maximum and minimum principal stress was little changed.The foot of the slope at the shear stress increases with the depth of excavation. The diversification process of plastic zone shows that because of the existence of F₂₅ fault broken zone, a large range of plastic zone appears near fault broken zone due to the role of shear and pressure.And a good linking plastic zone occurs along the fault zone. In addition, it search for the most dangerous slip surface of slope through the Geo-slope software under the current state and calculate the slope stability factor.