In terms of surrounding rock control in large section open-off cut

open-off cut No. 5206 in a mine is selected as study case. The principal stress difference

deformation and fracture field are studied in the process of width from 6 m to 10 m with UDEC. Research results show that: the principal stress differences increase gradually in shallow part and decrease in depth. With the width increasing

the maximal principal stress difference maintains a constant level at first

then decreases gradually in the roof

and decreases at first

then remains constant in the floor

and increases gradually in the rib. The moving range of peak: rib>roof>floor. The curve of displacement in roof decrease exponentially

but has obvious inflection point

which decrease terracedly in the floor. The maximal surface displacement: roof>side walls>floor. The fracture field is divided into three areas: fracture transfixion area

fracture area and microfracture area

which are all distributed as semi-ellipse

the extent of cut through:middle part>two sides and shallow part>deep part. It is believed that high-performance bolt hold the slippage of fracture effectively. The double truss cable can be anchored in the shoulder angle area

which has no fracture

and pre-tension overlays the area. Also

the double truss cable can close the shallow part of roof and reduce principal stress difference. Based on above

a high strength and high pre-tension bolting support scheme of band net and double truss anchor are proposed. The open-off cut achieves self-stabilization after 10 days when it is dug out

the total roof separation is 3 mm

and the roof-to-floor relative convergence is 125 mm

both sides relative convergence is 94 mm.