CN115113285A - A water inrush risk assessment method for grouting reinforcement of coal seam floor - Google Patents

Abstract

The invention discloses a water inrush risk assessment method for grouting reinforcement of a coal seam floor. The method comprises the steps of: 1. determining the position of the area to be reinforced; 2. collecting the original apparent resistivity of the area to be reinforced before reinforcement; 3. 4. Determine the effective reinforcement area in the area to be reinforced after grouting reinforcement; 5. Evaluate the water inrush risk level of the area to be reinforced according to the effective reinforcement area in the area to be reinforced after grouting reinforcement. The invention determines the position of the to-be-reinforced area, and measures the apparent resistivity before and after grouting reinforcement of the to-be-reinforced area, determines the effective reinforcement area in the to-be-reinforced area after grouting reinforcement, and then determines the effective reinforcement area in the to-be-reinforced area according to the effective reinforcement area in the to-be-reinforced area. The water inrush hazard level of the area to be strengthened is evaluated, and the water inrush hazard level determined by the evaluation is more accurate, which has a realistic and positive guiding role for the safety of coal mine production, and improves the safety of coal mine production.

Description

A water inrush risk assessment method for grouting reinforcement of coal seam floor

technical field

The invention belongs to the technical field of grouting reinforcement of coal seam floor, and in particular relates to a water inrush risk assessment method for grouting reinforcement of coal seam floor.

Background technique

Safe and efficient coal mining is a major event related to the national economy and people's livelihood. my country is one of the countries with the largest coal production in the world. At the same time, the geological and hydrogeological conditions of coal mines in my country are very complex. Many coal seams are threatened by various water bodies during the mining process. Over the years, with the continuous increase in mining depth, mining intensity and mining breadth of coal mine production, the hydrogeological conditions of coal fields have become more and more complex, the threat to mine safety production by the confined water of the floor has become increasingly serious, and there are still many accidents caused by flooding. If it happens, it has brought great losses to people's lives and properties. The unfavorable factors of water have seriously restricted the sustainable development of the coal industry and affected environmental projects such as water conservation and coal mining. Up to now, mine water damage is still a major hidden danger in coal mine safety production. The prevention and control measures for ash water damage mainly include drainage and pressure reduction, curtain grouting, and floor grouting reinforcement. The slurry fills and occupies the cracks and small dissolution gaps of the floor strata, consolidates and cements the stope floor, enhances the resistance of the floor strata against mining and high-confined water damage, and prevents the high-confined aquifer of the floor from bursting. water accident. At present, there are many technical means for the detection of grouting effect, mainly for the monitoring of karst grouting in the shallow ground and the detection of tunnel grouting. The technical means used are mainly electric sounding, high-density direct current method, Rayleigh wave, etc. The detection technology of grouting in goaf of coal mine is mainly direct current method; however, there is no better technical means and evaluation method to detect the effect of grouting reinforcement of coal seam floor.

Therefore, there is currently a lack of a method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor with simple method steps and novel and reasonable design to detect and evaluate the effect of grouting reinforcement of coal seam floor.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a water inrush risk assessment method for grouting reinforcement of coal seam floor in view of the above-mentioned deficiencies in the prior art. The method has simple steps. The apparent resistivity before and after grouting reinforcement is measured respectively to determine the effective reinforcement area in the area to be reinforced after grouting reinforcement. The water hazard level is more accurate, has a realistic and positive guiding role for the safety of coal mine production, improves the safety of coal mine production, and is easy to popularize and use.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor, which is characterized in that the method comprises the following steps:

Step 1. Determine the location of the area to be reinforced;

Step 2: Collect the original apparent resistivity of the area to be reinforced before reinforcement;

Step 3. Perform grouting reinforcement on the area to be reinforced;

Step 4: Determine the effective reinforcement area in the area to be reinforced after grouting reinforcement;

Step 5: Evaluate the water inrush risk level of the area to be reinforced according to the effective reinforced area in the area to be reinforced after grouting reinforcement.

The above-mentioned method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor is characterized in that: in step 1, the position of the area to be reinforced is determined, and the specific process is as follows:

Determine the layers of the coal seam floor, aquifer and aquifer below the coal mining face, and the area of the aquifer located in the vertical upward movement area is the area to be reinforced.

The above-mentioned method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor is characterized in that: in step 2, the original apparent resistivity of the area to be reinforced before reinforcement is collected, and the specific process is as follows:

Step 201: Arrange M groups of measuring points sequentially from back to front along the length direction of the coal mining face, and each group of measuring points includes a first measuring point located in the transport roadway and a second measuring point located in the return air roadway; wherein , M is a positive integer, and M≥3;

Step 202: Measure the apparent resistivity of the area to be strengthened at the M groups of measuring points, respectively, to obtain the original apparent resistivity sequence set of the M groups of measuring points to be strengthened. Similarly, when measuring the apparent resistivity of the area to be reinforced at the mth group of measuring points, the following steps are mainly included:

Step 2021: Place the transient electromagnetic instrument at the first measuring point of the mth group of measuring points, so that the horizontal plane where the transmitting coil of the transient electromagnetic instrument is located is perpendicular to the vertical plane where the central axis of the transport roadway is located, and then the The transmitting coil of the transient electromagnetic instrument rotates 90° clockwise. During the rotating process of the transmitting coil of the transient electromagnetic instrument, the transient electromagnetic instrument measures the apparent resistivity of the area to be reinforced according to the set measurement interval, and obtains the mth group of measurements. The original apparent resistivity of the area to be reinforced at different angles at the first measuring point of the point; where m is the number of the measuring point, 1≤m≤M, and the measurement interval is 10°～15°;

Step 2022, place the transient electromagnetic meter at the second measuring point of the mth group of measuring points, so that the horizontal plane where the transmitting coil of the transient electromagnetic meter is located and the vertical plane where the central axis of the return air tunnel is located are vertically arranged, and then Rotate the transmitting coil of the transient electromagnetic instrument 90° counterclockwise. During the rotating process of the transmitting coil of the transient electromagnetic instrument, the transient electromagnetic instrument measures the apparent resistivity of the area to be reinforced according to the set measurement interval, and obtains the mth group. The original apparent resistivity of the area to be reinforced at different angles at the second measuring point of the measuring point;

Step 2023: The original apparent resistivity of the area to be reinforced at different angles at the first measurement point of the mth group of measurement points obtained in step 2021 and the second measurement point of the mth group of measurement points obtained in step 2022 are different. The original apparent resistivity of the area to be reinforced under the angle is arranged in the order of measurement time, and the original apparent resistivity sequence set ρ _0m of the area to be reinforced at the mth group of measuring points is obtained, and the original apparent resistivity sequence set ρ _0m includes A original apparent resistivity, the a-th original apparent resistivity in the original apparent resistivity sequence set p _0m is denoted as p _0ma ; wherein, A is a positive integer, a is the original apparent resistivity number, 1≤a≤A .

The above-mentioned method for evaluating the risk of water inrush by grouting reinforcement of coal seam floor is characterized in that: in step 3, grouting reinforcement is performed on the area to be reinforced, which mainly includes the following steps:

Step 301: Determine the hole diameter, start position and end position of the test hole to be constructed in the to-be-reinforced area, construct a test hole in the to-be-reinforced area, and perform grouting reinforcement in the test hole; wherein, the A test hole is arranged near the left end of the area to be reinforced, and the center of the test hole is located on the horizontal centerline of the area to be reinforced;

Step 302, according to the method described in step 202, measure the apparent resistivity of the area to be reinforced again at the M groups of measuring points, and obtain a first set of apparent resistivity sequences of the M to-be-reinforced areas; The apparent resistivity of the area to be reinforced at the point is measured, and the first apparent resistivity sequence set ρ _1m of the area to be reinforced at the mth group of measurement points is obtained, and the first apparent resistivity sequence set ρ _1m includes A first apparent resistivity series. Resistivity, the a-th first apparent resistivity in the first apparent resistivity sequence set ρ _1m is denoted as ρ _1ma ;

Step 303: Perform data processing on the first apparent resistivity sequence set and the original apparent resistivity sequence set at the M groups of measuring points to obtain the effective reinforcement area and effective reinforcement width of the test boreholes at the M groups of measurement points; The data processing methods for the first apparent _resistivity sequence set at the point and the original apparent resistivity sequence set are the same. When _0m performs data processing, it mainly includes the following steps:

计算得到第a个第一视电阻率的增幅Z_1a；Step 3031: Match A first apparent resistivities in the first apparent resistivity sequence set p _1m and A original apparent resistivities in the original apparent resistivity sequence set p _0m one by one, and calculate the mth group respectively. The increase of the first apparent resistivity of A at the measuring point; among them, the calculation method of the increase of the first apparent resistivity of the A is the same. When calculating the increase of the first apparent resistivity of the a, the formula

Calculate the increase Z _1a of the a-th first apparent resistivity;

Step 3032, according to the increase of the first apparent resistivity of the A, determine the effective reinforcement area of the test hole at the mth group of measuring points; wherein, the division basis of the effective reinforcement area of the test hole is: when the a first view When the increase of the resistivity ρ _1ma Z _1a ≥ 10%, the area corresponding to the a-th first apparent resistivity is located in the effective reinforcement area of the test drill hole;

Step 3033, measuring the average width of the effective reinforcement area of the test hole at the mth group of measuring points as the effective reinforcement width b _1m of the test hole at the mth group of measurement points;

计算待加固区域内测试钻孔的平均有效加固宽度

Step 304, according to the formula

Calculate the average effective reinforcement width of the test drill holes in the area to be reinforced

确定待加固区域内待施工的注浆孔的数量；其中，

表示向上取整，B₁为待加固区域的最大宽度；Step 305, according to the formula

Determine the number of grouting holes to be constructed in the area to be reinforced; where,

Indicates rounded up, B ₁ is the maximum width of the area to be reinforced;

Step 306 , construct N grouting holes along the length direction of the area to be reinforced, and perform grouting reinforcement in the N grouting holes to complete the grouting reinforcement of the area to be reinforced; wherein, the structure of the grouting holes is the same as that of the grouting hole. The structure of the test hole is the same, the centers of the N grouting holes are all located on the same horizontal plane as the center of the test hole, and the hole distance between two adjacent grouting holes in the N grouting holes is k,

The above-mentioned method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor is characterized in that: in step 4, the effective reinforcement area in the area to be reinforced after grouting reinforcement is determined, and the specific process is as follows:

Step 401: According to the method described in Step 302, measure the apparent resistivity of the area to be reinforced again at the M groups of measuring points to obtain a second set of apparent resistivity sequences of the M to-be-reinforced areas; The apparent resistivity of the area to be reinforced at the point is measured, and the second apparent resistivity sequence set ρ _2m of the area to be reinforced at the mth group of measurement points is obtained, and the second apparent resistivity sequence set ρ _2m includes A second apparent resistivity sequence set ρ 2m Resistivity, the a-th second apparent resistivity in the second apparent resistivity sequence set ρ _2m is denoted as ρ _2ma ;

Step 402: According to the method described in step 303, perform data processing on the second apparent resistivity sequence set and the original apparent resistivity sequence set at the M groups of measuring points, and determine the effective reinforcement of the N grouting holes at the M groups of measuring points. area.

The above-mentioned method for evaluating the water inrush risk of grouting reinforcement of coal seam floor is characterized in that: in step 5, the water inrush risk level of the to-be-reinforced area is evaluated according to the effective reinforcement area in the to-be-reinforced area after grouting reinforcement, and the specific process is: as follows:

When the effective reinforcement areas of two adjacent grouting holes at any one of the M groups of measurement points are not connected, there is a risk of water inrush in the area to be reinforced;

When the effective reinforcement areas of the two adjacent grouting holes at each group of measurement points in the M groups of measurement points are connected, there is no risk of water inrush in the area to be reinforced.

The above-mentioned method for evaluating the risk of water inrush by grouting reinforcement of coal seam floor is characterized in that: in step 301, the starting position and the ending position of the test hole are both located in front of the opening of the working face, and the starting position of the test hole is Determined by the width of the coal mining face, the distance L ₁ =2B ₀ +L ₀ between the starting position of the test borehole and the incision on the face, where B ₀ is the width of the coal mining face, and L ₀ is the test drill hole The distance between the end position of the hole and the opening of the working face, the value of L ₀ ranges from 20m to 40m.

The beneficial effect of the present invention is that the original apparent resistivity sequence set and the second apparent resistivity sequence set of the to-be-reinforced area are obtained by determining the position of the to-be-reinforced area and measuring the apparent resistivity before and after the grouting and strengthening of the to-be-reinforced area. , and according to the original apparent resistivity sequence set and the second apparent resistivity sequence set of the area to be reinforced, determine the effective reinforcement area in the area to be reinforced after grouting reinforcement, and then according to the effective reinforcement area in the area to be reinforced The water inrush risk level is evaluated, and the water inrush risk level determined by the evaluation is more accurate. At the same time, it can visually and intuitively reflect the water inrush risk area of the coal seam floor and the corresponding risk level of each area, which is realistic for coal mine safety production. The positive guiding role of improving the safety of coal mine production.

The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments.

Description of drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a schematic structural diagram of the present invention.

3 is a schematic diagram of the positional relationship of the area to be reinforced, the transport roadway, the air return roadway, the test drilling hole and the grouting hole according to the present invention.

Explanation of reference numbers:

1—Coal working face; 2—Coal seam floor; 3—Water barrier;

4—Aquifer; 5—Vertical Upward Movement Area; 6—Area to be Reinforced;

6-1—reinforced section; 6-2—safety section; 7—transport roadway;

8—Return air tunnel; 9—First measuring point; 10—Second measuring point;

11—transient electromagnetic instrument; 12—test drilling; 13—grouting hole.

Detailed ways

As shown in Figure 1, a method for evaluating the risk of water inrush for grouting reinforcement of a coal seam floor according to the present invention includes the following steps:

Step 1. Determine the location of the area to be reinforced;

Step 2: Collect the original apparent resistivity of the area to be reinforced before reinforcement;

Step 3. Perform grouting reinforcement on the area to be reinforced;

Step 4: Determine the effective reinforcement area in the area to be reinforced after grouting reinforcement;

Step 5: Evaluate the water inrush risk level of the area to be reinforced according to the effective reinforced area in the area to be reinforced after grouting reinforcement.

The beneficial effect of the present invention is that the original apparent resistivity sequence set and the second apparent resistivity of the to-be-reinforced area 6 are obtained by determining the position of the to-be-reinforced area 6 and measuring the apparent resistivity of the to-be-reinforced area 6 before and after grouting reinforcement. According to the original apparent resistivity sequence set and the second apparent resistivity sequence set of the to-be-reinforced area 6, the effective reinforcement area in the to-be-reinforced area 6 after grouting reinforcement is determined, and then according to the effective reinforcement in the to-be-reinforced area 6 The water inrush risk level of the area to be strengthened is evaluated in the area. The water inrush risk level determined by the evaluation is more accurate. At the same time, it can visually and intuitively reflect the water inrush risk area of the coal seam floor and the corresponding risk level of each area. , has a realistic and positive guiding role for coal mine safety production, and improves the safety of coal mine production.

As shown in Figure 2, in this embodiment, the location of the area to be reinforced is determined in step 1, and the specific process is as follows:

Determine the layers of the coal seam floor 2 , the water barrier layer 3 and the aquifer 4 below the coal mining face 1 , and the area of the water barrier layer 3 in the vertical upward movement zone 5 is the area to be strengthened 6 .

In this embodiment, it should be noted that, during the mining process of the coal mining face 1, the deformation and breakage of the water barrier layer 3 under the coal mining face 1 mainly presents three different changes: First, the coal mining work The water barrier 3 remained intact before the mining of face 1; secondly, the water barrier 3 was gradually bent and deformed during the mining of coal face 1; finally, the water barrier 3 was obviously broken after the mining of coal face 1, and it moved vertically upward. The water barrier layer 3 in zone 5 is broken first. Therefore, the area of the water barrier layer 3 located in the vertical upward movement zone 5 is taken as the area to be strengthened 6, and the area to be strengthened is grouted for reinforcement. The injected grout diffuses in the area 6 to be reinforced, and mixes and solidifies with the rock mass in the area 6 to be reinforced, which improves the mechanical properties of the rock mass of the water barrier 3, increases the impermeability of the water barrier 3, and improves the barrier properties. The ability of the water layer 3 to resist deformation can effectively avoid the water inrush of the coal seam floor 2 caused by the breaking of the water barrier layer 3 .

In this embodiment, in actual use, the maximum width of the to-be-reinforced area 6 is taken as the overall width of the to-be-reinforced area 6, so that the to-be-reinforced area 6 has a rectangular structure, which is convenient to ensure the reinforcement effect of the to-be-reinforced area 6.

As shown in Figures 2 and 3, in this embodiment, in step 2, the original apparent resistivity of the area to be reinforced before the reinforcement is collected, and the specific process is as follows:

Step 201 , arrange M groups of measuring points in sequence from back to front along the length direction of the coal mining face 1 , each group of measuring points includes a first measuring point 9 located in the transport roadway 7 and a second measuring point located in the return air roadway 8 . Measuring point 10; among them, M is a positive integer, and M≥3;

Step 202: Measure the apparent resistivity of the regions 6 to be reinforced at the M groups of measuring points, respectively, to obtain the original apparent resistivity sequence set of the M regions 6 to be reinforced, and the apparent resistivity of the regions 6 to be reinforced at the M groups of measuring points. The measurement methods are the same. When measuring the apparent resistivity of the area 6 to be reinforced at the mth group of measuring points, the following steps are mainly included:

Step 2021: Place the transient electromagnetic meter 11 at the first measuring point 9 of the mth group of measuring points, so that the horizontal plane where the transmitting coil of the transient electromagnetic meter 11 is located is perpendicular to the vertical plane where the central axis of the transport tunnel 7 is located. Layout, and then turn the transmitting coil of the transient electromagnetic meter 11 90° clockwise. During the rotating process of the transmitting coil of the transient electromagnetic meter 11, the transient electromagnetic meter 11 will measure the apparent resistivity of the area 6 to be reinforced according to the set measurement interval. Carry out measurement to obtain the original apparent resistivity of the area 6 to be reinforced at different angles at the first measurement point 9 of the mth group of measurement points; where m is the measurement point number, 1≤m≤M, and the measurement interval is 10°～15° °;

Step 2022, place the transient electromagnetic meter 11 at the second measuring point 10 of the mth group of measuring points, so that the horizontal plane where the transmitting coil of the transient electromagnetic meter 11 is located is in the vertical plane where the central axis of the return air tunnel 8 is located. Vertical layout, and then rotate the transmitting coil of the transient electromagnetic meter 11 by 90° counterclockwise. During the rotation of the transmitting coil of the transient electromagnetic meter 11, the transient electromagnetic meter 11 measures the apparent resistance of the area 6 to be strengthened according to the set measurement interval. to measure the original apparent resistivity of the area 6 to be reinforced at different angles at the second measuring point 10 of the mth group of measuring points;

Step 2023, the original apparent resistivity of the area 6 to be reinforced at different angles at the first measurement point 9 of the mth group of measurement points obtained in step 2021, and the second measurement point of the mth group of measurement points obtained in step 2022 The original apparent resistivities of the regions 6 to be reinforced at 10 different angles are arranged in the order of measurement time, and the original apparent resistivity sequence set ρ _0m of the regions 6 to be reinforced at the mth group of measuring points is obtained, the original apparent resistivity The sequence set p _0m includes A original apparent resistivities, and the a-th original apparent resistivity in the original apparent resistivity sequence set p _0m is denoted as p _0ma ; wherein, A is a positive integer, a is the original apparent resistivity number, 1≤a≤A.

In this embodiment, it should be noted that when the apparent resistivity of the area to be reinforced 6 is measured by the transient electromagnetic instrument 11, according to the principle of electromagnetic induction, a high-power transient electromagnetic device is placed in the transport roadway 7 or the air return roadway 8. Instrument 11, the sudden change of the large current of the transient electromagnetic instrument 11 excites the transient electromagnetic field, and the low-frequency part of these transient electromagnetic fields can effectively enter the rock layer where the area 6 to be strengthened is located, and a secondary induction is excited in the rock layer where the area 6 to be strengthened is located The electromotive force, the secondary induced electromotive force is related to the conductivity of the rock layer where the area to be reinforced The apparent resistivity of the rock layer where the reinforcement area 6 is located is convenient to measure, and no other drilling construction is required in the coal mine roadway, which saves time and effort, and has high measurement accuracy, which is convenient for popularization and use;

In step 201, M groups of measuring points are sequentially arranged from back to front along the length direction of the area to be strengthened 6, and the first group of measuring points in the M group of measuring points is located in the same vertical position as the end position of the test hole 12 in the area to be strengthened 6. On the plane, the last set of measuring points in the M group of measuring points is located on the same vertical plane as the starting position of the test hole 12 in the area to be reinforced 6; each set of measuring points includes the first measuring point 9 and the second measuring point 10. By measuring the apparent resistivity of the area 6 to be reinforced around the set of measuring points at the first measuring point 9 and the second measuring point 10 of each group of measuring points, it is possible to measure the apparent resistivity in a segment around the set of measuring points. All-round apparent resistivity measurement is performed in the area 6 to be reinforced, with a wide measurement range and high measurement accuracy;

By measuring the apparent resistivity of the area 6 to be reinforced at the M groups of measuring points, it is convenient to evaluate the overall reinforcement effect of the area 6 to be reinforced in the later stage, and the evaluation accuracy is high;

In step 202, when measuring the apparent resistivity of the area to be reinforced 6 at each measuring point, the transient electromagnetic instrument 11 needs to be rotated to ensure that the measurement range of the transient electromagnetic instrument 11 covers the entire area to be reinforced 6, thereby improving The evaluation accuracy of this evaluation method.

In this embodiment, in step 2021, when the transmitting coil of the transient electromagnetic instrument 11 rotates 90° clockwise, the transient electromagnetic instrument 11 rotates with the side away from the coal mining face 1 as the center; in step 2022, the instantaneous When the transmitting coil of the variable electromagnetic instrument 11 is rotated 90° counterclockwise, the transient electromagnetic instrument 11 rotates with the side away from the coal mining face 1 as the center.

As shown in Figures 2 and 3, in this embodiment, the grouting reinforcement of the area to be reinforced in step 3 mainly includes the following steps:

Step 301: Determine the hole diameter, start position and end position of the test hole 12 to be constructed in the to-be-reinforced area 6, construct a test hole 12 in the to-be-reinforced area 6, and perform grouting reinforcement in the test hole 12 ; Wherein, the test hole 12 is arranged near the left end of the area 6 to be reinforced, and the center of the test hole 12 is located on the horizontal centerline of the area 6 to be reinforced;

Step 302, according to the method described in step 202, measure the apparent resistivity of the regions 6 to be reinforced again at the M groups of measuring points, and obtain the first set of apparent resistivity sequences of the M regions 6 to be reinforced; The apparent resistivity of the to-be-reinforced area 6 at the group measuring points is measured, and the first apparent resistivity sequence set ρ _{1m of the to-be-reinforced area 6 at the mth group of measuring points is obtained, and the first apparent resistivity sequence set ρ 1m includes} A a first apparent resistivity, the a-th first apparent resistivity in the first apparent resistivity sequence set ρ _1m is denoted as ρ _1ma ;

Step 303: Perform data processing on the first apparent resistivity sequence set and the original apparent resistivity sequence set at the M groups of measuring points to obtain the effective reinforcement area and effective reinforcement width of the test borehole 12 at the M groups of measurement points; The data processing methods for the first apparent resistivity sequence set at the measuring _point and the original apparent resistivity sequence set are the same. When ρ _0m performs data processing, it mainly includes the following steps:

计算得到第a个第一视电阻率的增幅Z_1a；Step 3031: Match A first apparent resistivities in the first apparent resistivity sequence set p _1m and A original apparent resistivities in the original apparent resistivity sequence set p _0m one by one, and calculate the mth group respectively. The increase of the first apparent resistivity of A at the measuring point; among them, the calculation method of the increase of the first apparent resistivity of the A is the same. When calculating the increase of the first apparent resistivity of the a, the formula

Calculate the increase Z _1a of the a-th first apparent resistivity;

Step 3032: Determine the effective reinforcement area of the test hole 12 at the mth group of measuring points according to the increase of the A first apparent resistivity; wherein, the division basis of the effective reinforcement area of the test hole 12 is: when the ath When the increase Z _1a of the apparent resistivity ρ _1ma is greater than or equal to 10%, the area corresponding to the a-th first apparent resistivity is located in the effective reinforcement area of the test hole 12;

Step 3033, measure the average width of the effective reinforcement area of the test hole 12 at the mth group of measuring points as the effective reinforcement width b _1m of the test hole 12 at the mth group of measurement points;

计算待加固区域6内测试钻孔12的平均有效加固宽度

Step 304, according to the formula

Calculate the average effective reinforcement width of the test drill holes 12 in the area to be reinforced 6

确定待加固区域6内待施工的注浆孔 13的数量；其中，

表示向上取整，B₁为待加固区域6的最大宽度；Step 305, according to the formula

Determine the number of grouting holes 13 to be constructed in the to-be-reinforced area 6; wherein,

Represents rounded up, B ₁ is the maximum width of the area to be reinforced 6;

Step 306 , construct N grouting holes 13 along the length direction of the area to be reinforced, and perform grouting reinforcement in the N grouting holes 13 to complete the grouting reinforcement of the area 6 to be reinforced; wherein, grouting The structure of the hole 13 is the same as that of the test hole 12 , the centers of the N grouting holes 13 are all located on the same horizontal plane as the center of the test hole 12 , and the two adjacent grouting holes 13 among the N grouting holes 13 are located at the same level. The hole distance between them is k,

并根据待加固区域6 内测试钻孔12的平均有效加固宽度

确定所施工注浆孔13的个数。In this embodiment, in actual use, in step 3, a test hole 12 is constructed in the area 6 to be reinforced, and grouting reinforcement is performed in the test hole 12, and the measured values of the test hole 12 before and after grouting reinforcement are compared. The original apparent resistivity sequence set and the first apparent resistivity sequence set, to determine the average effective reinforcement width of the test hole 12 in the area to be reinforced 6

And according to the average effective reinforcement width of the test hole 12 in the area 6 to be reinforced

Determine the number of grouting holes 13 to be constructed.

In this embodiment, the area to be reinforced 6 includes a reinforced section 6-1 and a safety section 6-2, the test drill hole 12 and the grouting hole 13 are located in the reinforced section 6-1, and the safety section 6-2 is located in the reinforced section 6- 1 and the incision on the working face, the distance between the end position of the test hole 12 and the incision on the working face is the length of the safety section 6-2. 1. When grouting the test drill hole 12 and the grouting hole 13, the normal operation of the opening of the working face is affected, and the safety range is reserved and the safety is good.

In this embodiment, the test hole 12 and the grouting hole 13 are both directional long-distance holes, the diameter of the grouting hole 13 is equal to that of the test hole 12 , and the starting position of the grouting hole 13 is the same as that of the test hole 12 The starting position of the grouting hole 13 is the same as that of the test hole 12 .

In this embodiment, by performing grouting reinforcement in the grouting hole 13 , the grout is mixed and solidified with the rock mass in the area to be reinforced, so as to improve the mechanical properties of the rock mass of the water barrier layer 3 and increase the impermeability of the water barrier layer 3 The performance improves the ability of the water barrier layer 3 to resist deformation, and effectively avoids the water inrush from the coal seam floor 2 caused by the breakage of the water barrier layer 3 .

In this embodiment, in step 4, the effective reinforcement area in the area to be reinforced after grouting reinforcement is determined, and the specific process is as follows:

Step 401: According to the method described in step 302, measure the apparent resistivity of the region 6 to be reinforced again at the M groups of measuring points to obtain a second set of apparent resistivity sequences of the M regions 6 to be reinforced; The apparent resistivity of the to-be-reinforced area 6 is measured at the group measuring points, and the second apparent resistivity sequence set ρ _{2m of the to-be-reinforced area 6 at the mth group of measuring points is obtained, and the second apparent resistivity sequence set ρ 2m includes} A a second apparent resistivity, the a-th second apparent resistivity in the second apparent resistivity sequence set ρ _2m is denoted as ρ _2ma ;

Step 402: According to the method described in step 303, perform data processing on the second apparent resistivity sequence set and the original apparent resistivity sequence set at the M groups of measuring points, and determine the effectiveness of the N grouting holes 13 at the M groups of measuring points. Reinforced area.

In this embodiment, in step 4, the apparent resistivity of the to-be-reinforced region 6 after grouting reinforcement is measured by the transient electromagnetic instrument 11, to obtain a second apparent resistivity sequence set, and compare the to-be-reinforced region 6 before and after grouting reinforcement The collected original apparent resistivity sequence set and the second apparent resistivity sequence set are used to obtain the effective reinforcement area of the area to be reinforced 6. The measurement efficiency is high, and it can visually and intuitively reflect the water inrush risk area of the coal seam floor, as well as each area. Corresponding to the level of risk level, and the accuracy of the results is good.

In this embodiment, in step 5, the water inrush risk level of the to-be-reinforced area is evaluated according to the effective reinforced area in the to-be-reinforced area after grouting reinforcement. The specific process is as follows:

When the effective reinforcement areas of two adjacent grouting holes 13 at any group of measurement points in the M group of measurement points are not connected, there is a risk of water inrush in the to-be-reinforced area 6;

When the effective reinforcement areas of the two adjacent grouting holes 13 at each group of measurement points in the M groups of measurement points are connected, there is no danger of water inrush in the area to be reinforced 6 .

In this embodiment, it should be noted that, in step 5, by observing whether the effective reinforcement areas of the adjacent two grouting holes 13 in the area to be reinforced after grouting reinforcement are connected, the area to be reinforced during the mining of the coal mining face 1 is determined. The water inrush risk level of 6 is evaluated, and the water inrush risk level of the area to be reinforced after grouting reinforcement is obtained. When connected, it means that the effective reinforcement area of the to-be-reinforced area 6 covers the width of the to-be-reinforced area 6, and the water barrier 3 is less affected by the mining stress disturbance of the coal mining face 1. At this time, there is no sudden change in the to-be-reinforced area 6. Water danger; when the effective reinforcement areas of two adjacent grouting holes 13 at any group of measurement points in the M group of measurement points are not connected, it means that the effective reinforcement area of the area to be reinforced at this time does not cover the area to be reinforced 6 The width of the water barrier 3 is greatly affected by the mining stress disturbance of the coal mining face 1. At this time, there is a danger of water inrush in the area 6 to be reinforced.

In this embodiment, in step 301, the start position and the end position of the test hole 12 are both located in front of the opening of the working face. The start position of the test hole 12 is determined by the width of the coal mining face 1. The test hole The distance L ₁ =2B ₀ +L ₀ between the starting position of 12 and the opening of the working face, B ₀ is the width of the coal mining working face 1, and L ₀ is the end position of the test hole 12 and the working face incision The distance between the eyes, the value of L ₀ ranges from 20m to 40m.

The above are only preferred embodiments of the present invention and do not limit the present invention. Any simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technology of the present invention. within the scope of the program.

Claims (7)

1. a method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor, is characterized in that, the method comprises the following steps: Step 1. Determine the location of the area to be reinforced; Step 2: Collect the original apparent resistivity of the area to be reinforced before reinforcement; Step 3. Perform grouting reinforcement on the area to be reinforced; Step 4: Determine the effective reinforcement area in the area to be reinforced after grouting reinforcement; Step 5: Evaluate the water inrush risk level of the area to be reinforced according to the effective reinforced area in the area to be reinforced after grouting reinforcement. 2. according to a kind of coal seam floor grouting reinforcement water inrush risk assessment method according to claim 1, it is characterized in that: in step 1, determine the position of the area to be reinforced, and the concrete process is as follows: Determine the layers of the coal seam floor (2), aquifer (3), and aquifer (4) below the coal mining face (1), and the area of the aquifer (3) within the vertical upward movement zone (5) is to be Reinforced area (6). 3. according to a kind of coal seam floor grouting reinforcement water inrush risk assessment method according to claim 1, it is characterized in that: in the step 2, collect the original apparent resistivity of the area to be reinforced before the reinforcement, and the concrete process is as follows: Step 201. M groups of measuring points are arranged in sequence from back to front along the length direction of the coal mining face (1), each group of measuring points includes a first measuring point (9) located in the transport roadway (7) and a first measuring point (9) located in the return air. The second measuring point (10) in the roadway (8); wherein, M is a positive integer, and M≥3; Step 202: Measure the apparent resistivity of the area to be reinforced (6) at the M groups of measuring points respectively, and obtain the original apparent resistivity sequence set of the M areas to be reinforced (6), and the area to be reinforced (6) at the M groups of measuring points. ) of the apparent resistivity are all the same, when measuring the apparent resistivity of the area to be reinforced (6) at the mth group of measuring points, the following steps are mainly included: Step 2021: Place the transient electromagnetic instrument (11) at the first measuring point (9) of the mth group of measuring points, so that the horizontal plane where the transmitting coil of the transient electromagnetic instrument (11) is located is in the middle of the transportation roadway (7). The vertical plane where the axis is located is arranged vertically, and then the transmitting coil of the transient electromagnetic instrument (11) is rotated 90° clockwise. During the rotation of the transmitting coil of the transient electromagnetic instrument (11), the transient electromagnetic instrument (11) Measure the apparent resistivity of the area to be reinforced (6) according to the set measurement interval, and obtain the original apparent resistivity of the area to be reinforced (6) at different angles at the first measuring point (9) of the mth group of measuring points; wherein , m is the measurement point number, 1≤m≤M, the measurement interval is 10°～15°; Step 2022: Place the transient electromagnetic instrument (11) at the second measuring point (10) of the mth group of measuring points, so that the horizontal plane where the transmitting coil of the transient electromagnetic instrument (11) is located is the same as the return air tunnel (8). The vertical plane where the central axis is located is arranged vertically, and then the transmitting coil of the transient electromagnetic instrument (11) is rotated 90° counterclockwise. During the rotation of the transmitting coil of the transient electromagnetic instrument (11), the transient electromagnetic instrument (11) ) measure the apparent resistivity of the area to be reinforced (6) according to the set measurement interval, and obtain the original apparent resistivity of the area to be reinforced (6) at different angles at the second measuring point (10) of the mth group of measuring points; Step 2023: Calculate the original apparent resistivity of the area to be reinforced (6) at different angles at the first measurement point (9) of the mth group of measurement points obtained in step 2021, and the mth group of measurement points obtained in step 2022. The original apparent resistivity of the area to be strengthened (6) at different angles at the second measuring point (10) is arranged in the order of measurement time, and the original apparent resistivity sequence of the area to be strengthened (6) at the mth group of measuring points is obtained Set p _0m , the original apparent resistivity sequence set p _0m includes A original apparent resistivities, and the a-th original apparent resistivity in the original apparent resistivity sequence set p _0m is denoted as p _0ma ; wherein, A is a positive Integer, a is the original apparent resistivity number, 1≤a≤A. 4. according to a kind of coal seam floor grouting reinforcement water inrush risk assessment method according to claim 3, it is characterized in that: in step 3, carry out grouting reinforcement to the area to be reinforced, which mainly comprises the following steps: Step 301: Determine the hole diameter, start position and end position of the test hole (12) to be constructed in the to-be-reinforced area (6), construct a test hole (12) in the to-be-reinforced area (6), and test Grouting reinforcement is carried out in the drill hole (12); wherein, the test drill hole (12) is arranged near the left end of the area to be reinforced (6), and the center of the test drill hole (12) is located at the center of the area to be reinforced (6). horizontal centerline; Step 302, according to the method described in step 202, measure the apparent resistivity of the area to be reinforced (6) again at the M groups of measuring points, and obtain a first set of apparent resistivity sequences of the M areas to be reinforced (6); wherein , measure the apparent resistivity of the area to be reinforced (6) at the mth group of measuring points, and obtain the first apparent resistivity sequence set ρ _1m of the area to be strengthened (6) at the mth group of measuring points, the first apparent resistivity The resistivity sequence set ρ _1m includes A first apparent resistivities, and the a-th first apparent resistivity in the first apparent resistivity sequence set ρ _1m is denoted as ρ _1ma ; Step 303: Perform data processing on the first apparent resistivity sequence set and the original apparent resistivity sequence set at the M groups of measuring points to obtain the effective reinforcement area and effective reinforcement width of the test borehole (12) at the M groups of measurement points; The data processing methods for the first apparent _resistivity sequence set and the original apparent resistivity sequence set at the M group of measuring points are the same. When the sequence set ρ _0m performs data processing, it mainly includes the following steps: Step 3031: Match A first apparent resistivities in the first apparent resistivity sequence set p _1m and A original apparent resistivities in the original apparent resistivity sequence set p _0m one by one, and calculate the mth group respectively. The increase of the first apparent resistivity of A at the measuring point; among them, the calculation method of the increase of the first apparent resistivity of the A is the same. When calculating the increase of the first apparent resistivity of the a, the formula

Calculate the increase Z _1a of the a-th first apparent resistivity; Step 3032: Determine the effective reinforcement area of the test hole (12) at the mth group of measuring points according to the increase in the A first apparent resistivity; wherein, the division basis of the effective reinforcement area of the test hole (12) is: when When the increase Z _1a of the a-th first apparent resistivity ρ _1ma is ≥10%, the area corresponding to the a-th first apparent resistivity is located in the effective reinforcement area of the test drill hole (12); Step 3033, measuring the average width of the effective reinforcement area of the test hole (12) at the mth group of measuring points as the effective reinforcement width b _1m of the test hole (12) at the mth group of measurement points; Step 304, according to the formula

Calculate the average effective reinforcement width of the test drill holes (12) in the area to be reinforced (6)

Step 305, according to the formula

Determine the number of grouting holes (13) to be constructed in the area to be reinforced (6); wherein,

Indicates rounded up, B ₁ is the maximum width of the area to be reinforced (6); Step 306: Construct N grouting holes (13) along its length in the area to be reinforced (6), and perform grouting reinforcement in the N grouting holes (13) to complete the grouting of the area to be reinforced (6). Grouting reinforcement; wherein, the structure of the grouting hole (13) is the same as that of the test drill hole (12), and the centers of the N grouting holes (13) are located on the same horizontal plane as the center of the test drill hole (12), The hole distance between two adjacent grouting holes (13) in the N grouting holes (13) is k,

5. according to a kind of coal seam floor grouting reinforcement water inrush risk assessment method according to claim 4, it is characterized in that: in step 4, determine the effective reinforcement area in the area to be reinforced after grouting reinforcement, and the concrete process is as follows: Step 401: According to the method described in step 302, the apparent resistivity of the area to be reinforced (6) is measured again at the M groups of measuring points to obtain a second set of apparent resistivity sequences of the M areas to be reinforced (6); wherein , measure the apparent resistivity of the area to be reinforced (6) at the mth group of measuring points, and obtain the second apparent resistivity sequence set ρ _2m of the area to be strengthened (6) at the mth group of measuring points, the second apparent resistivity The resistivity sequence set ρ _2m includes A second apparent resistivities, and the a-th second apparent resistivity in the second apparent resistivity sequence set ρ _2m is denoted as ρ _2ma ; Step 402: According to the method described in step 303, perform data processing on the second apparent resistivity sequence set and the original apparent resistivity sequence set at the M groups of measuring points, and determine N grouting holes at the M groups of measuring points (13) effective reinforcement area. 6. according to a kind of coal seam floor grouting reinforcement water inrush risk assessment method according to claim 5, it is characterized in that: in step 5, according to the effective reinforcement area in the area to be reinforced after grouting reinforcement, the water inrush risk of the area to be reinforced The specific process is as follows: When the effective reinforcement areas of two adjacent grouting holes (13) at any group of measurement points in the M group of measurement points are not connected, the area to be reinforced (6) is at risk of water inrush; When the effective reinforcement areas of the adjacent two grouting holes (13) at each group of measurement points in the M groups of measurement points are connected, there is no danger of water inrush in the area to be reinforced (6). 7. A method for evaluating the risk of water inrush for grouting reinforcement of coal seam floor according to claim 4, characterized in that: in step 301, the starting position and the ending position of the test borehole (12) are both located at the opening of the working face In front of the test hole (12), the starting position of the test hole (12) is determined by the width of the coal mining face ( _{1 )} . +L ₀ , B ₀ is the width of the coal mining face (1), L ₀ is the distance between the end position of the test borehole (12) and the opening of the working face, and the value of L ₀ ranges from 20m to 40m .

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