Coal-rock composite roof difference scale anchor rod combined supporting method

Abstract

The invention discloses a coal-rock composite roof difference scale anchor rod combined supporting method, which comprises the following steps of: transmitting electromagnetic pulses within the roof range of a pre-dug roadway by using a geological radar for advanced detection, determining interfaces of a complete rock area, a cracked rock area and a crashed rock area in the composite roof range of 50-100 meters of the pre-dug roadway according to a reflected signal received by the geological radar, and forming a three-dimensional composite roof structure geologic model by means of a computer; and calculating the length of a difference scale anchor rod through subarea geometric parameters of the section of the model, and selecting an appropriate anchor rod to support a composite roof and to assist a metal net and a steel belt to form a combined supporting structure. As the three-dimensional composite roof structure geologic model is built, complex geological data of the roof can be expressed very visually and accurately; the form of the visual interface is advantageous for field staff to operate and determine the length of the anchor rod. Besides, the deformation of the roof can be effectively controlled, the number of the anchor rods can be reduced, and a great quantity of supporting materials and a great amount of maintenance cost can be saved; and as a result, the per unit area yield and the per unit area input are improved, and the safety production is guaranteed.

Description

technical field [0001] The invention relates to a joint support method of coal-rock composite roofs with different scale bolts, and is especially suitable for preventing and controlling roadways (coal roadways, rock mines) with weak interlayers (coal lines, mudstone) and geological weak surfaces under the action of high stress in coal mines. lane) composite roof. Background technique [0002] With the increasing demand for coal resources, coal mining in most mining areas in my country has entered the deep mining stage. Under deep conditions, the geological structure is complex, various geological conditions (faults, groundwater, etc.) interact with each other, and the unknown, complex, and non-repeatable environment makes the excavation and maintenance of deep roadways more and more difficult. Due to the well-developed discontinuous surfaces such as bedding and joints in the surrounding rock, the roadway with composite roof is soft and broken, so it is a roadway with diffic...

AI Technical Summary

Problems solved by technology

Due to the well-developed discontinuous surfaces such as bedding and joints in the surrounding rock, the roadway with composite roof is soft and broken, so it is a roadway with difficult conditions. Area roof fall accident seriously affects the safe excavation of the roadway

At present, anchors of uniform length are mostly used in bolt support and other combined support systems of bolts. Although the deformation of the roof can be effectively controlled, the distribution of the geological strata of the roof is not considered, and there are some regional instability phenomena, which also cause relatively large damage. big cost waste

There is also a combination of long and short bolt support structures, but the design is generally based on the ground stress calculated by simulation, with less consideration for the stratum structure, the random risk of the support effect is large, and the control effect on the roof separation is poor

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