|
Abstract Strength reduction method which is used to study stability of goaf overlapping roof based on catastrophe theory is established. The concepts of safety factor of overlapping roof are proposed. With the reduction of strength parameters，a cusp catastrophe model of vertical displacement of the midpoint of roof and reduction coefficient is built. The mutability of overlapping roof failure process can be reflected when this model is employed as the failure criterion. Taking double cuboid goafs for example，fitting logarithm function between safety factor of roof and thickness to span ratio is drawn. Fitting function shows that safety factor of roof is effected by the thickness to span ratio and span of roof. Using strength reduction method to study stability of multilayer goafs overlapping roof based on catastrophe theory，it is obtained that the upper goaf overlapping roof instability can induce instability evolution of the lower goaf overlapping roof. Studying the stability of multilayer goafs overlapping roofs in No.105 tin orebody of Gaofeng mining area，as result，except for goafs No.1 and No.2，the rest overlapping roofs are stable in the main，whose safety factors are over 1.5. Strength reduction method based on catastrophe theory provides a new research approach for stability analysis of goafs.
|
|
Received: 08 January 2010
|
|
|
|
