JIANG Bei, LI Shu-cai, WANG Qi, et al. Design method of roof anchor cable for deep large section mining roadways based on the upper bound method[J]. 2017, 38(8): 2351-2357.
DOI:
JIANG Bei, LI Shu-cai, WANG Qi, et al. Design method of roof anchor cable for deep large section mining roadways based on the upper bound method[J]. 2017, 38(8): 2351-2357.DOI: 10.16285/j.rsm.2017.08.024.
Design method of roof anchor cable for deep large section mining roadways based on the upper bound method
The aim of this study is to resolve the present control problems and the corresponding high-strength anchor cable control technology in deep large section roadways. This study was based on the Hoek-Brown criterion and the upper bound theorem of the limit analysis and also considered the stress of surrounding rock in the roof and the effect of supporting the load. On the above basis
the roof caving mechanism of large-section roadways was acquired. Furthermore
a design method for roofs was put forward for the minimum length and the pre-tightening force of an anchor cable. Since the design parameters of anchor cables was affected by established sensitivity indexes
it is important to investigate the effects of established sensitivity indexes on factors
such as the roadway’s width
the specific weight of the rock mass
the stress in the surrounding rock
the compressive strength and the tensile strength of the rock mass
anchor cable layout spacing and vertex anchor cable laying angle. According to the actual field conditions
engineering suggestions are proposed for controlling surrounding rocks in the deep large-section roadway. Finally
this design method was applied to determine the roof anchor parameters of transport gateway of 1305 Island Coal Face in the Kilometer Deep Well Zhaolou coal mine
which effectively controlled the deformation of surrounding rock. From research results
only when the roof anchor cable was anchored in stable rock and enough pre-tightening force was exerted
the roof rock caving and damage can be effectively controlled in high-stress large-section mining roadways. It is found that roof pre-tightening force for anchor cable decreased with the increase of tensile strength
compressive strength and empirical parameter A of rock mass. Besides
this roof pre-tightening force increased with increasing the width of the roadway
the specific weight of rock mass
the stress in the surrounding rock
the compressive strength and the tensile strength of rock mass
anchor cable layout spacing
vertex anchor cable laying angle and empirical parameter B of rock mass. Moreover
the highest sensitivity of all the influencing factors turned out to be the surrounding rock stress. This indicates that special attention should be paid to the influence of in-situ stress of the surrounding rock when designing the deep high-stress roadways. Therefore
the effective release of the surrounding rock stress can be achieved by using the high strength
high elongation anchor cable and adding the yieldable device. Meanwhile
the integrity of the surrounding rock can be improved by applying high pre-tightening force and grouting reinforcement
resulting in better control performance of surrounding rock.