A design method of a broken roadway expansion type anchoring agent

Abstract

The present application relates to a kind of broken roadway swelling type anchoring agent design method, belong to roadway supporting technical field.The loose broken roadway swelling type anchoring agent design method of the present application, first, the crack distribution in surrounding rock is detected, second, the pressure stress of anchoring agent to borehole wall and the radius of anchoring agent after consolidation under unconstrained condition are obtained by theoretical calculation, the expansion ratio required is calculated according to the two parameters, finally, the expansion ratio of anchoring agent is adjusted according to the expansion ratio, the integrity and stability of surrounding rock are improved, and the technical problems of anchoring agent shrinkage and low anchoring force in loose broken roadway are solved.

Description

TECHNICAL FIELD

[0001] The application relates to a design method of an expansion type anchoring agent for a broken roadway, and belongs to the field of mine roadway support. BACKGROUND

[0002] In the process of underground coal mining, the roadway support and reinforcement work must be done well in the broken surrounding rock roadway of the coal seam, and the development of the internal crack texture of the surrounding rock and the existence of the weak structural plane will lead to the broken surrounding rock of the roadway. When the broken surrounding rock roadway is anchored and supported, many cracks exist in the borehole, so that the anchoring force of the anchor rod is greatly reduced. In addition, 6%-10% of the volume shrinkage will be generated during the curing reaction of the resin anchoring agent, which seriously affects the anchoring performance of the resin anchoring agent. In order to eliminate the influence of the broken surrounding rock on the anchoring force and the shrinkage effect of the curing reaction, a specific proportion of expansion material is added in the initial stage of the curing reaction of the resin anchoring agent, so that the influence of the cracks of the broken surrounding rock on the anchoring force is reduced, and the shrinkage stress in the reaction process is completely eliminated.

[0003] In engineering practice, the composition ratio of the expansion anchoring agent is often used according to the past experience, and there is a lack of different treatment methods for different actual situations and a lack of quantitative design of the composition ratio and the expansion deformation. If the expansion stress is too large, the broken surrounding rock will be extruded, different anchor rods will face different broken surrounding rocks, different consolidation environments and different construction requirements, and therefore the expansion deformation of the expansion anchoring agent needs to be controlled. A new type of anchoring agent design method is needed for the loose broken roadway, so as to effectively improve the support requirements of the loose broken roadway, such as the shrinkage of the anchoring agent, the low anchoring force and the poor anchoring reliability. SUMMARY

[0004] In view of the anchoring and supporting problems of the loose broken roadway, the application provides a design method of an expansion type anchoring agent for a broken roadway, which can effectively improve the anchoring force and anchoring reliability of the anchor rod of the loose broken roadway and greatly improve the anchoring safety factor of the loose broken roadway.

[0005] In order to realize the above technical purpose, the application provides a design method of an expansion type anchoring agent for a broken roadway, which comprises the following steps:

[0006] The method comprises the following steps:

[0007] Step S1: drilling holes in the roadway roof or two sides, and detecting the crack depth l of the borehole by using an ultrasonic surrounding rock crack detector;

[0008] Step S2: test the natural density p of the rock around the roadway, the shear modulus G of the anchoring agent after curing without adding the expanding agent, and the shrinkage rate ψ of the anchoring agent after curing without adding the expanding agent;

[0009] Step S3: calculate the compressive stress P of the anchoring agent on the borehole wall by using a theoretical calculation method 外 , and the minimum value is the gravity of the surrounding rock in the range of the borehole fissure depth, and the calculation formula is:

[0010]

[0011] Step S4: calculate the radius r2 of the anchoring agent after curing in the case of no constraint by using an elastic mechanics calculation method;

[0012] Step S5: calculate the expansion ratio required by the resin anchoring agent by using a theoretical calculation method:

[0013]

[0014] In the formula, r3 is the radius of the anchor rod, r 孔 is the radius of the anchor rod borehole;

[0015] Step S6: design the proportion of the UEA expanding agent in the expanding anchoring agent, the UEA expanding agent including aluminum sulfate, aluminum oxide, potassium aluminum sulfate, and other anchoring agent materials including resin materials, high-strength fillers, curing agents, and accelerators.

[0016] Further, the elastic mechanics method is used to analyze the stress state of the anchoring agent after curing when analyzing the stress state of the anchoring agent: it is determined that the compressive stress of the expanding anchoring agent on the borehole wall and the anchor rod after curing makes it in the elastic stage, and at this time, the anchoring agent is a uniform elastic force body in all directions, which is subjected to the compressive stress of the internal anchor rod and the external borehole wall, and the general solution can be obtained by combining the function expression of the stress component and the compatibility equation in the polar coordinates, and the boundary conditions can be obtained by substituting the general solution:

[0017]

[0018] Let p = r2, Therefore

[0019] In the formula, r2 is the outer diameter of the anchoring agent after curing without the constraint of the surrounding rock, r 孔 is the inner diameter of the anchor rod borehole, and in the broken surrounding rock, it is the radius of the anchoring agent after curing when reaching the designed compressive stress, P 外 is the designed compressive stress of the anchoring agent after curing on the broken surrounding rock.

[0020] Further, in the step S6, the determination method of the expansion ratio: the volume ratio after consolidation under the conditions of whether the anchoring agent adds the expanding agent is used as the basis of the amount of the expanding agent.

[0021] Further, when the roadway for the expansion type anchoring agent is in a very broken environment, the parameters of the expansion type anchoring agent need to be multiplied by a coefficient, which is obtained by monitoring the environment and is related to the broken degree in the roadway wall.

[0022] Beneficial effects:

[0023] The ordinary anchoring agent has a consolidation shrinkage phenomenon, which greatly affects the effect of the anchor support, and the harm of the consolidation shrinkage in the loose broken roadway is more obvious, so the expansion type anchoring agent adding the expanding agent is often used, but there is a lack of scientific calculation method of the content of the expanding agent. The application can more scientifically and reasonably calculate the content of the expanding agent required in the anchoring agent used in the broken surrounding rock roadway. By controlling the proportion of the expanding agent in the anchoring agent, the effect of controlling the expansion deformation and the hole wall pressure stress after the expansion and consolidation of the anchoring agent is achieved, the anchoring effect of the anchor rod and the integrity of the surrounding rock are improved, and the further deformation of the broken surrounding rock is prevented. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The anchoring agent designed for the application is shown in the force schematic diagram,

[0025] Figure 2 The force schematic diagram of the broken surrounding rock in the roadway. DETAILED DESCRIPTION

[0026] The embodiments of the application will be further described below in combination with the drawings:

[0027] As Figure 1 shown, the design method of the expansion type anchoring agent of the broken roadway according to the application calculates the radius of the anchoring agent after consolidation under the pressure stress of the anchoring agent on the hole wall and the unrestrained condition by detecting the crack distribution in the surrounding rock, only the required expansion ratio is calculated, and finally the anchoring agent is prepared according to the expansion ratio, and the anchoring agent is a cylindrical structure.

[0028] The specific steps are as follows:

[0029] Step S1: drilling holes in the roadway roof or two sides, and detecting the crack depth l of the holes by using an ultrasonic surrounding rock crack detector;

[0030] Step S2: testing the natural density p of the surrounding rock of the roadway, the shear modulus G of the anchoring agent after solidification without adding the expanding agent, and the solidification shrinkage rate of the anchoring agent without adding the expanding agent;

[0031] Step S3: calculating the pressure stress P of the anchoring agent on the hole wall by using a theoretical calculation method 外The minimum value is the gravity of the surrounding rock in the fracture depth range of the borehole, and the calculation formula is:

[0032]

[0033] Step S4: using the calculation method of elastic mechanics, the radius r2 of the anchoring agent after consolidation under the condition of no constraint is calculated;

[0034] Step S5: using the theoretical calculation method, the expansion ratio required by the resin anchoring agent is calculated:

[0035]

[0036] In the formula, r3 is the radius of the anchor rod, r 孔 is the radius of the anchor rod hole;

[0037] Step S6: the proportion of UEA expander in the expanding anchoring agent is designed, the UEA expander includes aluminum sulfate, aluminum oxide, potassium aluminum sulfate, and other anchoring agent materials include resin material, high-strength filler, curing agent, accelerator; the determination method of the expansion ratio: using the volume ratio after consolidation under the condition of whether the anchoring agent is added with the expander as the basis for the amount of the expander added.

[0038] Step S7: the anchoring agent is placed in the borehole, and the anchor rod drill is started to stir the resin cartridge and apply a specified size of pre-tightening force.

[0039] When analyzing the stress state of the anchoring agent, the elastic mechanics method is used to analyze the stress state of the anchoring agent after consolidation: it is determined that the pressure stress of the expanding anchoring agent after consolidation on the borehole wall and the anchor rod body is in the elastic stage, and at this time the anchoring agent is a uniform elastic force body in all directions, which is subjected to the internal anchor rod body and the external hole wall pressure stress, the function expression of the stress component and the compatibility equation in polar coordinates are obtained, and the general solution is obtained by substituting the boundary conditions:

[0040]

[0041] Let ρ=r2, Therefore

[0042] In the formula, r2 is the outer diameter of the anchoring agent after consolidation without surrounding rock constraint, r 孔 is the inner diameter of the anchor rod hole, and in the broken surrounding rock, it is the radius of the anchoring agent after consolidation reaching the designed pressure stress, P 外 is the designed pressure stress of the anchoring agent after solidification on the broken surrounding rock.

[0043] When the expanding type anchoring agent is used in the extremely broken environment of the roadway, the parameters of the expanding type anchoring agent need to be multiplied by a coefficient, which is obtained by monitoring the environment and is related to the broken degree of the roadway wall.

[0044] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for designing the proportion of expanding agent in an expanding anchoring agent for broken roadways, characterized in that: By detecting the distribution of fissures in the surrounding rock, the compressive stress of the anchoring agent on the borehole wall and the radius of the anchoring agent after consolidation under unconstrained conditions are calculated. Then, the required expansion ratio is calculated, and finally the anchoring agent is prepared according to the expansion ratio. The anchoring agent is a cylindrical structure. Includes the following steps: Step S1: Drill holes in the roof or sides of the tunnel and use an ultrasonic rock fracture detector to detect the depth l of the borehole fractures. Step S2: Test the natural density ρ of the rock surrounding the tunnel, the shear modulus G of the anchoring agent after curing without the addition of expansion agent, and the consolidation shrinkage rate ψ of the anchoring agent without the addition of expansion agent. Step S3: Calculate the compressive stress P exerted by the anchoring agent on the borehole wall using theoretical calculation methods. 外 Its minimum value is the gravity of the surrounding rock within the borehole fracture depth range, and the calculation formula is: ； Step S4: Calculate the radius r2 of the anchoring agent after consolidation under unconstrained conditions using the calculation method of elasticity mechanics; Step S5: Calculate the required expansion ratio of the resin anchoring agent using theoretical calculations. ； In the formula, r3 is the radius of the anchor rod used, r 孔 The radius of the anchor bolt hole; Step S6: Design the proportion of UEA expanding agent in the expanding anchoring agent. UEA expanding agent includes aluminum sulfate, alumina, and potassium aluminum sulfate. Other anchoring agent materials include resin materials, high-strength fillers, curing agents, and accelerators.

2. The method for designing the proportion of expanding agent in an expanding anchoring agent for broken roadways according to claim 1, characterized in that, When analyzing the stress state of the anchoring agent, the stress state after consolidation is analyzed using elastic mechanics: It is assumed that the compressive stress on the borehole wall and anchor rod after consolidation puts the expanding anchoring agent in an elastic stage, and that the anchoring agent at this time is an isotropic, uniformly elastic body subjected to compressive stress from the internal anchor rod and external borehole wall. By simultaneously establishing the functional expressions of the stress components and the compatibility equations in polar coordinates, the general solution can be obtained. Substituting the boundary conditions, we get: ； Let ρ = r2, ,so ; In the formula, r2 is the radius of the anchoring agent after consolidation in the unconstrained state, r 孔 Let P be the radius of the anchor bolt hole. 外 This refers to the compressive stress exerted by the anchoring agent on the borehole wall.

3. The method for designing the proportion of expanding agent in an expanding anchoring agent for broken roadways according to claim 1, characterized in that, In step S6, the expansion ratio is determined by using the volume ratio after consolidation under two conditions: whether or not an expansion agent is added to the anchoring agent, as the basis for the amount of expansion agent added.

4. The method for designing the proportion of expanding agent in an expanding anchoring agent for broken roadways according to claim 1, characterized in that, When the roadway in which the intumescent anchor is used is in an extremely fractured environment, the parameters of the intumescent anchor need to be multiplied by a coefficient, which is obtained through environmental monitoring and is related to the degree of fracture within the roadway wall.

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