Fluidized filling grouting detection and optimal drilling arrangement method in old goaf

Abstract

The present invention discloses a method for fluidized filling grouting detection and optimal drilling arrangement in old goaf areas, and relates to the technical field of filling grouting in old goaf areas of mines. It includes: drilling test holes and detection holes on the ground, preparing fluidized filling slurry and magnetic fluidized detection slurry containing magnetic debris, placing an electromagnetic detector at the bottom of the detection hole to detect the signal, and recording it as the first magnetic field signal; injecting magnetic fluidized detection slurry into the test hole, and after the injection is completed, injecting fluidized filling slurry again, and after stopping the grouting, detecting and receiving the signal again through the electromagnetic detector, recording it as the last magnetic field signal, and fitting the overall distribution map of the magnetic field of the goaf area under the signal; combining theoretical knowledge to calculate the maximum radius value of a grouting; and finally obtaining the optimal drilling hole spacing value according to the maximum radius value. While effectively responding to the grouting filling in the goaf area, the method of the present invention also lays an important foundation for related research such as the flow law of grouting in the goaf area.

Description

Technical Field

[0001] The invention relates to the technical field of filling and grouting in old goaf areas of mines, and in particular to a method for fluidized filling and grouting detection and optimal drilling arrangement in old goaf areas. Background Art

[0002] The old goaf areas formed underground after coal mining, the generation and existence of this adverse geological body pose a serious threat to the safe construction and stable operation of surface buildings (structures). Coal mining subsidence area refers to the area where the surface subsidence depth is greater than 10mm due to coal mining. The agricultural land in the coal mining subsidence area that has reduced or no production due to underground coal mining, as well as the affected construction land and unused land are called coal mining subsidence areas. At present, the problems of limited space for transformation and development and insufficient construction land in most mining cities are becoming increasingly prominent. It is urgent to carry out the construction and utilization of coal mining subsidence areas, ensure the supply of urban construction land, and promote urban transformation and development.

[0003] When treating old goafs, grouting filling is used as one of the treatment methods. The current difficulties mainly lie in the fact that the optimal grouting radius for old goafs is still unclear, resulting in inappropriate spacing of drilling holes. In addition, the flow process and state of the slurry in the goaf are difficult to accurately judge, making it difficult to control the amount of grouting during the grouting process, which can easily lead to insufficient slurry injection, causing the formation to remain in an unstable state, or excessive slurry injection, increasing the cost of project investment.

[0004] In summary, when grouting and filling old goafs, the design of grouting holes is particularly critical. The intervals between adjacent grouting holes and the number of grouting holes need to be strictly analyzed and calculated. Therefore, from the perspective of saving engineering costs and the safety of surface structures above the old goafs, it is of great significance to determine the grouting amount during the grouting process in the old goafs. Summary of the invention

[0005] The purpose of the present invention is to provide a method for fluidized filling grouting detection and optimal drilling arrangement in old goaf areas. The method can monitor the grouting diffusion range. While effectively responding to the grouting filling in the goaf area, it also lays an important foundation for related research such as the grouting flow law in the goaf area.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for fluidized filling grouting detection and optimal drilling arrangement in old goaf areas comprises the following steps in sequence:

[0008] a. Determine the ground position corresponding to the central axis of the old goaf tunnel according to the geological data above and below the coal mine, and drill a test hole on the ground; according to the direction of the old goaf tunnel, drill a detection hole on one side of the test hole along the direction, and the distance between the detection hole and the test hole is 50m;

[0009] b. preparing fluidized filling slurry and magnetic fluidized testing slurry containing magnetic debris;

[0010] c. Placing the electromagnetic detector at the bottom of the detection hole, and turning on the electromagnetic detector to detect and receive signals, and record them as the first magnetic field signal; moving the electromagnetic detector to scan the entire space of the goaf, transmitting the obtained information to the host on the ground through signals, and storing and recording, and fitting the overall distribution map of the magnetic field of the goaf in combination with theoretical knowledge;

[0011] d. Inject magnetic fluidized testing slurry into the test hole. After the magnetic fluidized testing slurry is injected, inject the fluidized filling slurry. When the grouting pressure reaches the grouting limit and the electromagnetic detector located in the test hole detects that the magnetic field no longer changes significantly, stop grouting;

[0012] e. Detect and receive the signal again through the electromagnetic detector, record it as the last magnetic field signal, and fit the overall distribution map of the magnetic field in the goaf under the signal;

[0013] f. Compare the magnetic field distribution diagrams of the goaf area obtained in step c and step e, and calculate the maximum radius value of a grouting operation;

[0014] g. Twice the maximum radius of the first grouting in step f is the optimal drilling hole spacing value;

[0015] h. According to the optimal drilling hole spacing value described in step g, drill the second test hole, the third test hole...the Nth test hole in sequence, and complete the filling of the goaf by injecting fluidized filling slurry into each test hole.

[0016] As a preferred embodiment of the present invention, in step a, the test hole and the detection hole have the same pore size.

[0017] As another preferred embodiment of the present invention, in step b, the fluidized filling slurry is mainly prepared by mixing cement, fly ash, coal slag, coal gangue and water; the magnetic fluidized detection slurry is mainly prepared by mixing cement, fly ash, coal slag, magnetite waste rock and water.

[0018] Preferably, in step c, the dynamic monitoring time interval of the electromagnetic detector is 5 to 10 minutes.

[0019] Preferably, in step d, the injection amount of the magnetic fluidization detection slurry is 100m3 ~500m 3 .

[0020] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0021] (1) The present invention proposes a method for fluidized filling grouting detection and optimal drilling arrangement in old goaf areas. The filling material selected in this method is composed of fluidized filling slurry and magnetic fluidized detection slurry containing magnetic debris. The magnetic fluidized detection slurry containing magnetic debris can be coordinated with an electromagnetic detector located in the detection hole to obtain an overall distribution map of the magnetic field in the goaf under the signal, which is convenient for judging the interval between adjacent drill holes and the timing of drilling.

[0022] (2) The slurry selected by the present invention, magnetite waste rock as magnetic detection material can solve part of the waste rock for iron mines and protect the environment. On the other hand, magnetite as grouting material has the same performance as ordinary grouting material and does not affect the effect. Fluidized filling materials include fly ash, coal slag and coal gangue and other bulk solid wastes, which effectively solve the problem of environmental pollution caused by bulk solid wastes. Grouting in old goafs can effectively control the subsidence area.

[0023] (3) The use of magnetic fluidization detection materials and electromagnetic detectors can accurately determine the maximum grouting range of the actual grouting area, and then determine the left and right drilling distances, to ensure that the grouting material fills the goaf to the greatest extent and reduce the waste of drilling and filling materials.

[0024] The present invention arranges the optimal boreholes in the old goaf area, while ensuring the filling effect, it also reduces the engineering investment cost. The method of the present invention can monitor the grouting diffusion range. The present invention solves the technical problem that the old goaf area is prone to collapse by ensuring the optimal borehole arrangement. At the same time, the method of the present invention is mainly for direct grouting of the tunnels in the old goaf area, which is easier to implement and control than grouting of the overlying rock strata in the goaf area. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the optimal drilling arrangement of the present invention;

[0027] In the figure:

[0028] 1. Test hole, 2. Inspection hole, 3. Cutting hole, 4. Slope. DETAILED DESCRIPTION

[0029] The present invention proposes a fluidized filling grouting detection and optimal drilling arrangement method for old goaf areas. In order to make the advantages and technical solutions of the present invention clearer and more specific, the present invention is specifically described below in conjunction with specific embodiments.

[0030] The present invention proposes a method for fluidized filling grouting detection and optimal drilling arrangement in old goaf areas, and the specific steps are as follows:

[0031] Step 1: Determine the ground position corresponding to the central axis of the goaf tunnel according to the geological data above and below the coal mine, and drill a test hole on the ground with a diameter of 250mm;

[0032] According to the direction of the old goaf roadway, a detection hole is drilled on one or both sides of the test hole along the direction. The distance between the detection hole and the test hole is 50m, and the diameter of the detection hole is 250mm.

[0033] Step 2: preparing a fluidized filling slurry and a magnetic fluidized detection slurry containing magnetic debris;

[0034] The fluidized filling slurry is mainly prepared by mixing cement, fly ash, coal slag, coal gangue and water; wherein: the coal slag and coal gangue are crushed by a secondary crusher and ground by a ball mill, the particle size after crushing is less than 10mm, and the particle size after grinding is less than 0.4mm; cement: fly ash: coal slag: coal gangue = 1:2:1.5:1.5, and the solid mass fraction is 76%; the solid mass ratio of coal gangue after crushing and grinding is 1:3, and the solid mass ratio of coal slag after crushing and grinding is 1:2;

[0035] The magnetic fluidization test slurry is prepared by mixing cement, fly ash, coal slag, magnetite waste rock and water. The particle size of magnetite waste rock after crushing is less than 10mm, and the particle size after grinding is less than 0.4mm; among them: cement: fly ash: magnetite waste rock: coal gangue = 1:2:1.5:1.5, and the solid mass fraction is 76%. The solid mass ratio of magnetite waste rock after crushing and grinding is 1:3, and the solid mass ratio of coal slag after crushing and grinding is 1:2.

[0036] Step 3: Place the electromagnetic detector at the bottom of the detection hole, turn on the electromagnetic detector, detect and receive signals, and record them as the first magnetic field signal; move the electromagnetic detector to scan the entire space of the goaf, transmit the obtained information to the host on the ground through signals, store and record, and fit the overall distribution map of the magnetic field in the goaf in combination with theoretical knowledge; during the grouting process, the electromagnetic detector performs dynamic detection at a time interval of 5 to 10 minutes;

[0037] Step 4: Inject magnetic fluidization testing slurry into the test hole with an injection volume of 100m 3 ~500m 3 After the magnetic fluidized testing slurry is injected, the fluidized filling slurry is injected. When the grouting pressure reaches the grouting limit and the electromagnetic detector located in the detection hole detects that the magnetic field no longer changes significantly, the grouting is stopped;

[0038] Step 5: Detect and receive the signal again through the electromagnetic detector, record it as the last magnetic field signal, and fit the overall distribution map of the magnetic field in the goaf under the signal;

[0039] Step 6: Compare the magnetic field distribution diagrams of the goaf area obtained in step 3 and step 5, and calculate the maximum radius value of a grouting operation;

[0040] Step 7: Twice the maximum radius of a grouting operation in step 6 is the optimal drilling hole spacing value;

[0041] Step 8. According to the optimal drilling hole spacing value described in step 7, drill the second test hole, the third test hole...the Nth test hole in sequence, and complete the filling of the goaf by injecting fluidized filling slurry into each test hole.

[0042] Most of the raw materials in the above-mentioned fluidized filling slurry and magnetic fluidized detection slurry, such as coal slag and coal gangue, come from coal mines where old goafs are located. While effectively solving the problem of environmental pollution caused by large amounts of solid waste, they can also effectively control the collapse area.

[0043] Embodiment 1:

[0044] Take a coal mine as an example. Figure 1 As shown, the figure shows the cut eye 3 and the flume 4, and the method of the present invention is adopted, and the specific steps are:

[0045] Step 1: According to the geological data of the coal mine, fluidized grouting is carried out on the old goaf of the 4# coal seam in the mine, the ground position corresponding to the centerline of the goaf is determined, and a test hole is drilled on the ground corresponding to the middle of the goaf. The diameter of the test hole is 250mm;

[0046] According to the direction of the old goaf, detection holes are drilled on both sides of the test hole along the direction. The distance between detection hole 2 and test hole 1 is 50m, and the diameter of the detection hole is 250mm.

[0047] Step 2: preparing a fluidized filling slurry and a magnetic fluidized detection slurry containing magnetic debris;

[0048] The magnetic fluidization detection slurry is prepared by mixing cement, fly ash, coal-fired slag, magnetite waste rock and water. The particle size of the magnetite waste rock after crushing is less than 10mm, and the particle size after grinding is less than 0.4mm; among them: cement: fly ash: magnetite waste rock: coal gangue = 1:2:1.5:1.5, and the solid mass fraction is 76%. The solid mass ratio of the magnetite waste rock after crushing and grinding is 1:3, and the solid mass ratio of the coal-fired slag after crushing and grinding is 1:2. Preparation of magnetic fluidization detection slurry 200m 3 .

[0049] The fluidized filling slurry is mainly prepared by mixing cement, fly ash, coal slag, coal gangue and water; wherein: the coal slag and coal gangue are crushed by a secondary crusher and ground by a ball mill, the particle size after crushing is less than 10 mm, and the particle size after grinding is less than 0.4 mm; cement: fly ash: coal slag: coal gangue = 1:2:1.5:1.5, and the solid mass fraction is 76%; the solid mass ratio of the coal gangue after crushing and grinding is 1:3, and the solid mass ratio of the coal slag after crushing and grinding is 1:2.

[0050] Step 3: Place the electromagnetic detector at the bottom of the detection hole, turn on the electromagnetic detector, detect and receive signals, and record them as the first magnetic field signal; move the electromagnetic detector to scan the entire space of the goaf, transmit the obtained information to the host on the ground through signals, store and record, and fit the overall distribution map of the magnetic field in the goaf in combination with theoretical knowledge; during the grouting process, the electromagnetic detector performs dynamic detection at a time interval of 10 minutes;

[0051] Step 4: Inject magnetic fluidization testing slurry into the test hole at a volume of 200m 3 After the magnetic fluidized testing slurry is injected, the fluidized filling slurry is injected. When the grouting pressure reaches the grouting limit and the electromagnetic detector located in the detection hole detects that the magnetic field no longer changes significantly, the grouting is stopped;

[0052] Step 5: Detect and receive the signal again through the electromagnetic detector, record it as the last magnetic field signal, and fit the overall distribution map of the magnetic field in the goaf under the signal;

[0053] Step 6: Compare the magnetic field distribution diagrams of the goaf obtained in step 3 and step 5, and calculate that the maximum radius of a grouting is 20m;

[0054] Step 7: To ensure the grouting effect, take twice the maximum radius of the grouting in step 6 as the optimal drilling hole spacing;

[0055] Step 8. According to the optimal drilling hole spacing value described in step 7, drill the second test hole, the third test hole...the Nth test hole in sequence, and complete the filling of the goaf by injecting fluidized filling slurry into each test hole.

[0056] Effect:

[0057] The ground in the area was monitored during the grouting process of an old goaf in a coal mine and during the construction of buildings. At five measuring points on the west side of the data processing center, the ground gradually rose during the grouting project and then dropped again after the grouting was completed. With the construction of the central building, the ground sank. When the second floor of the building was completed (300 days after the completion of the grouting reinforcement of the goaf), the ground sank by a maximum of 6 mm, the elevation change tended to be gentle, and the average settlement rate was 0.011 mm / d, which met the relevant requirements of the "Code for Measurement of Building Deformation". It is believed that the ground deformation has entered a stable stage.

[0058] Parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0059] It should be further noted that the specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for fluidized filling grouting detection and optimal drilling arrangement in old goaf, characterized in that: The following steps are included in sequence: a. Determine the ground position corresponding to the central axis of the old goaf tunnel according to the geological data above and below the coal mine, and drill a test hole on the ground; according to the direction of the old goaf tunnel, drill a detection hole on one side of the test hole along the direction, and the distance between the detection hole and the test hole is 50m; b. preparing fluidized filling slurry and magnetic fluidized testing slurry containing magnetic debris; c. Placing the electromagnetic detector at the bottom of the detection hole, and turning on the electromagnetic detector to detect and receive signals, and record them as the first magnetic field signal; moving the electromagnetic detector to scan the entire space of the goaf, transmitting the obtained information to the host on the ground through signals, and storing and recording, and fitting the overall distribution map of the magnetic field of the goaf in combination with theoretical knowledge; d. Inject magnetic fluidized testing slurry into the test hole. After the magnetic fluidized testing slurry is injected, inject the fluidized filling slurry. When the grouting pressure reaches the grouting limit and the electromagnetic detector located in the test hole detects that the magnetic field no longer changes significantly, stop grouting; e. Detect and receive the signal again through the electromagnetic detector, record it as the last magnetic field signal, and fit the overall distribution map of the magnetic field in the goaf under the signal; f. Compare the magnetic field distribution diagrams of the goaf area obtained in step c and step e, and calculate the maximum radius value of a grouting operation; g. Twice the maximum radius of the first grouting in step f is the optimal drilling hole spacing value; h. According to the optimal drilling hole spacing value described in step g, drill the second test hole, the third test hole...the Nth test hole in sequence, and complete the filling of the goaf by injecting fluidized filling slurry into each test hole.

2. The method for fluidized filling grouting detection and optimal drilling arrangement in old goaf according to claim 1 is characterized by: In step a, the test hole and the detection hole have the same aperture.

3. The method for fluidized filling grouting detection and optimal drilling arrangement in old goaf according to claim 1 is characterized in that: In step b, the fluidized filling slurry is mainly prepared by mixing cement, fly ash, coal slag, coal gangue and water; the magnetic fluidized detection slurry is mainly prepared by mixing cement, fly ash, coal slag, magnetite waste rock and water.

4. The method for fluidized filling grouting detection and optimal drilling arrangement in old goaf according to claim 1 is characterized in that: In step c, the dynamic monitoring time interval of the electromagnetic detector is 5 to 10 minutes.

5. The method for fluidized filling grouting detection and optimal drilling arrangement in old goaf according to claim 1, characterized in that: In step d, the injection amount of the magnetic fluidization detection slurry is 100m 3 ~500m 3 .

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