Method for three-dimensional support by using long, medium, and short anchor rods

Abstract

The invention relates to a method for three-dimensional support by using long, medium, and short anchor rods. The method comprises first support and second support. The second support comprises: (1) applying short anchor rods to control surface surrounding rocks, to form a stable bearing arch to anchor and support; (2) applying medium-length anchor rods, to anchor the bearing arch formed by the short anchor rods on a relatively stable rock stratum, and forming a new thickened bearing arch at the same time, so the bearing arch becomes stable; (3) applying long anchor rods to further anchor the above bearing arches on a stable rock stratum. The method is advantaged in that characteristics of soft rocks determine that support of the soft rocks must be rapid and timely, and surrounding rocks are effectively sealed, to put an end to a channel which may continue weathering and peeling, strength of the surrounding rocks are maintained to the largest extent, so after roadway driving, rapid support with certain strength must be performed, and the surrounding rocks are sealed in time, to put an end to a channel which absorbs water and expands, thereby achieving an objective of roadway support.

Description

technical field [0001] The invention relates to a method for three-dimensional support using long, medium and short bolts. Background technique [0002] The Longkou mining area is a typical Tertiary "soft rock" mining area. The mine field coal-measure strata are mainly composed of mudstone, oily mudstone, clay rock, carbonaceous mudstone, oil shale, coal and sandstone. The coal seam and the roof and floor are loose and soft coal rocks with poor stability in a large area, and the inner and outer ring layers of the surrounding rock structure are unstable, so the maintenance of the roadway is very difficult, and it will affect the mining operation and mining. The deep increase is sensitive, and it has the characteristics of getting worse as it is repaired. Moreover, due to the abnormal development of coal seam joints in the area, with high porosity and good air permeability, the unidirectional compressive strength of the coal seam adjacent to the roof is mostly 5.3-20MPa, th...

AI Technical Summary

Problems solved by technology

[0003] Due to the poor engineering stability of the soft rock roadway, the short self-stabilization period and the characteristic of pressure display, once the roadway is excavated, the interbedded mudstone and sandstone on the roof will be destroyed due to delamination in depth and weathering. In order to avoid the roadway roof caving, Roof bolt support must be carried out immediately within 0.5-1.5 hours of roadway excavation, and because the surrounding rock has the characteristics of strong expansion, disintegration and rheology after water absorption, it must be sprayed and sealed within 7-8 hours , the excavated surrounding rock has not been given enough pressure relief space and time. Therefore, although this emergency remedial support has sealed the roof in time and effectively avoided the deepening of the loose broken zone, it has also just caused the stress to re-emerge in the later period. The reasons for centralized distribution increase the difficulty of support