Mountain area shallow coal seam mining ground fracture development position prediction method

Abstract

The invention discloses a mountain area shallow coal seam mining ground fracture development position prediction method. The method comprises the steps of mountain area ground surface horizontal movement deformation decomposition, mountain slope slippage horizontal movement solving, mountain area ground surface horizontal movement solving, mountain area ground surface horizontal deformation solving and ground fracture development position prediction. According to the method, the ground fracture development position is predicted by predicting the peak values of the ground surface horizontal movement and horizontal deformation by taking the mining subsidence theory as guidance and taking the horizontal movement and horizontal deformation as judgment indexes on the basis of the ground surface subsidence characteristics of mining of the shallow coal seam in the mountainous area and the high correlation between the ground fracture development position and the ground surface horizontal movement and horizontal deformation; the method changes the passive situation that the development position of the ground fracture is determined through a large amount of on-site actual measurement in the past, is simple and efficient in process, saves time and labor, is quick and accurate in prediction result, provides technical support for adopting a method for weakening the development of the ground fracture in advance, and has important practical significance for ecological restoration and environmental protection of the coal mining subsidence land in the mountainous area.

Description

Technical Field

[0001] The present invention belongs to the field of mining subsidence and ecological restoration in mines, and specifically relates to a method for predicting the development position of ground fissures in the mining of shallow buried coal seams in mountainous areas. Background Technique

[0002] Mountainous areas have the characteristics of complex surface environment, sensitive ecological environment, strong corrosion effect, etc. Coupled with the significant characteristics of shallow coal seam burial depth, close interlayer spacing, and repeated mining in coal seam mining, the ground fissures generated in the mining of shallow buried coal seams in mountainous areas not only seriously damage the ecological environment, but also trigger disasters such as landslides, dangerous rock collapses, mine water inrush and soil erosion, seriously threatening people's lives and property safety. It can be seen that the prevention and control of ground fissure disasters has become an important issue that needs to be solved urgently in the field of mining subsidence and ecological restoration in mines.

[0003] An important prerequisite for effectively reducing the development scale of ground fissures is to accurately predict the development position of ground fissures. The document with the application number 202110269525.5 discloses a method for predicting mining-induced ground fissures. According to the span of the overburden bearing structure and the arch height of the overburden when the roof weighting occurs, the maximum tensile stress on the upper boundary of the overburden arch beam structure is determined to judge the stability of the arch beam structure, and then whether surface cracks are generated is judged. The document with the application number 202110347385.9 discloses a comprehensive multi-index evaluation method for surface mining-induced cracks in shallow buried coal seams. By obtaining the basic parameters of ground fissures, dynamic change characteristics, and the observation and data processing of their connection degree with the underground goaf, the types of ground fissures are divided, and the ground fissures are classified and graded for evaluation. On the one hand, the above-mentioned documents predict whether ground fissures will occur on the surface through various methods, and on the other hand, evaluate the damage degree of ground fissures to the surface through multiple indexes. However, there are few reports on the prediction of the development position of ground fissures.

[0004] During the on-site measurement of surface subsidence and ground fissures in the mining of shallow buried coal seams in mountainous areas, it is found that the development position of ground fissures is closely related to the peak values of horizontal movement and horizontal deformation. The surface near the development position of ground fissures often shows peak values of horizontal movement and horizontal deformation. It can be seen that the key to predicting the development position of ground fissures lies in the prediction of surface horizontal movement and surface horizontal deformation. Therefore, it is crucial to accurately predict surface horizontal movement and horizontal deformation. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a method for predicting the development position of ground fissures in the mining of shallow buried coal seams in mountainous areas.

[0006] The technical solution for the present invention to solve the above technical problem is to provide a method for predicting the development position of ground fissures in the mining of shallow buried coal seams in mountainous areas, which is characterized in that the method includes the following steps:

[0007] Step 1. Decomposition of horizontal movement and deformation of mountain surface: Decompose the horizontal movement and deformation of the mountain surface into the horizontal movement and deformation of flat ground under the same mining geological conditions and the horizontal movement and deformation of hillside slip under the same mining geological conditions;

[0008] Among them, the horizontal movement of the mountain surface is expressed as:

[0009]

[0010] In formula (1), represents the horizontal movement of flat ground under the same mining geological conditions, represents the horizontal movement of hillside slip under the same mining geological conditions; x represents a certain point on the surface;

[0011] The horizontal deformation of the mountain surface is expressed as:

[0012]

[0013] In formula (2), represents the horizontal deformation of flat ground under the same mining geological conditions, represents the horizontal deformation of hillside slip under the same mining geological conditions;

[0014] Step 2. Solution of the horizontal movement of hillside slip Solve;

[0015] According to the superposition principle, find the vertical movement and the horizontal movement of hillside slip at a certain point x on the surface The horizontal movement of hillside slip and the vertical movement (x) of hillside slip form the movement S of hillside slip, as shown in formula (3):

[0016]

[0017] In formula (3), the vertical movement of hillside slip The horizontal movement of hillside slip (x) δ is the inclination angle of the movement S of hillside slip;

[0018] Then calculate the movement S of hillside slip according to formula (3) (x) ; Then, based on the existing surface subsidence observation data, obtain the expression of the movement S (x) of hillside slip, as shown in formula (4):

[0019]

[0020] In formula (4), T(x) is the surface feature coefficient, J (x) is the mountain influence function, W max is the maximum subsidence value of the flat ground under the same mining geological conditions; h m is the maximum height of the mountain; h (x) is the difference between the mining depth of a certain point x on the surface of the slope and the minimum mining depth within the mining range; H (x) is the mining depth of a certain point x on the surface of the slope; p (x) is the slope influence function, W (x) is the subsidence value of a certain point x on the surface of the flat ground under the same mining geological conditions; α (x) is the dip angle of the surface profile at a certain point x on the surface; r is the mining influence radius, r = H / tanβ, H is the average mining depth within the mining range, and β is the mining influence angle; A, B, C, and D represent the parameters of the mountain sliding amount;

[0021] Then substitute Equation (4) into Equation (3) and solve to obtain the horizontal movement of the hillside sliding which is:

[0022]

[0023] Step 3, Horizontal movement of the mountainous area surface Solve;

[0024] Substitute Equation (5) into Equation (1) to obtain the horizontal movement of the mountainous area surface

[0025]

[0026] Step 4, Horizontal deformation of the mountainous area surface Solve;

[0027] Take the first derivative of the horizontal movement of the mountainous area surface obtained in Step 3 to obtain the horizontal deformation of the mountainous area surface whose expression is:

[0028]

[0029] Step 5, Predict the development location of ground fissures: Collect and analyze the formation geological data of the prediction area, obtain the values of the parameters in Equation (4) and substitute them into Equations (6) and (7), calculate the predicted values of the horizontal movement of the mountainous area surface and the predicted values of the horizontal deformation of the mountainous area surface, and draw the change curve; then combine the change curve, mark the peak points, and judge the development location of ground fissures.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) Based on the characteristics of surface subsidence in the shallow coal seam mining in mountainous areas and the high correlation between the development position of ground fissures and the horizontal movement and horizontal deformation of the surface, guided by the theory of mining subsidence, with horizontal movement and horizontal deformation as the judgment indexes, the present invention predicts the development position of ground fissures by predicting the peak values of surface horizontal movement and horizontal deformation, changing the passive situation of determining the development position of ground fissures through a large number of on-site measurements in the past. The process is simple and efficient, saving time and effort, and the prediction result is rapid and accurate, providing technical support for taking measures to weaken the development of ground fissures in advance, and having important practical significance for the ecological restoration and environmental protection of coal mining subsidence areas in mountainous areas.

[0032] (2) On the one hand, according to the high correlation between the peak values of surface horizontal movement and horizontal deformation and the development position of ground fissures, the present invention proposes a method for predicting the development position of ground fissures by obtaining the predicted peak values of surface horizontal movement and horizontal deformation, ensuring the accuracy of the prediction of the development position of ground fissures. On the other hand, the present invention uses theoretical calculations and does not need to judge the development position of ground fissures through a large number of on-site measurements, significantly saving manpower, material resources and financial resources and reducing the economic cost.

[0033] (3) The expressions of surface horizontal movement and horizontal deformation proposed by the present invention fully consider the surface movement and deformation in the horizontal direction and the surface slip deformation along the slope direction in mountainous areas according to the characteristics of surface subsidence in the shallow coal seam mining in mountainous areas, effectively avoiding the inapplicability of the relevant calculation formulas for surface horizontal movement and horizontal deformation in plain areas, and the prediction result is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is the overall flowchart of the present invention;

[0035] Figure 2 is the comparison diagram of the predicted value and the measured value of the surface horizontal movement in the mountainous area of the 8912 working face in Embodiment 1 of the present invention;

[0036] Figure 3 is the comparison diagram of the predicted value and the measured value of the surface horizontal deformation in the mountainous area of the 8912 working face in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] The following are specific embodiments of the present invention. The specific embodiments are only used to further illustrate the present invention in detail and do not limit the protection scope of the present invention.

[0038] The present invention provides a method for predicting the development position of ground fissures in the shallow coal seam mining in mountainous areas (hereinafter referred to as the method), which is characterized in that the method includes the following steps:

[0039] Step 1. Decomposition of the horizontal movement and deformation of the mountainous area surface: Decompose the horizontal movement and deformation of the mountainous area surface into the horizontal movement and deformation of a flat ground under the same mining geological conditions and the horizontal movement and deformation of the hillside slip under the same mining geological conditions;

[0040] Among them, the horizontal movement of the mountainous area surface is expressed as:

[0041]

[0042] In formula (1), represents the horizontal movement of a flat ground under the same mining geological conditions, represents the horizontal movement of the hillside slip under the same mining geological conditions; x represents a certain point on the surface;

[0043] The horizontal deformation of the mountainous area surface is expressed as:

[0044]

[0045] In formula (2), represents the horizontal deformation of a flat ground under the same mining geological conditions, represents the horizontal deformation of the hillside slip under the same mining geological conditions;

[0046] Step 2. Solve the horizontal movement of the hillside slip Solve;

[0047] According to the superposition principle, find the vertical movement and the horizontal movement of the hillside slip at a certain point x on the surface The horizontal movement of the hillside slip and the vertical movement (x) of the hillside slip form the movement S of the hillside slip, as shown in formula (3):

[0048]

[0049] In formula (3), the vertical movement of the hillside slip The horizontal movement of the hillside slip (x) δ is the inclination angle of the movement S of the hillside slip;

[0050] Then calculate the movement S of the hillside slip according to formula (3) (x) ; Then, based on the existing surface subsidence observation data, obtain the expression of the movement S (x) of the hillside slip, as shown in formula (4):

[0051]

[0052] In formula (4), T(x) is the surface feature coefficient, J (x) is the mountain influence function, W max is the maximum subsidence value (m) of the flat ground under the same mining geological conditions; h m is the maximum height (m) of the mountain, which is the height difference from the highest point of the mountain to the lowest point of the flat ground; h (x) is the difference (m) between the mining depth of a certain point x on the surface of the slope and the minimum mining depth within the mining range (usually the valley position); H (x) is the mining depth (m) of a certain point x on the surface of the slope; p (x) is the slope influence function, W (x) is the subsidence value (m) of a certain point x on the surface of the flat ground under the same mining geological conditions; α (x) is the dip angle (°) of the surface profile at a certain point x on the surface; r is the mining influence radius (m), H is the average mining depth within the mining range, β is the mining influence angle; A, B, C, D represent the parameters of the landslide amount in the mountainous area, which are obtained according to the actual production geological conditions;

[0053] Then substitute Equation (4) into Equation (3) to solve for the horizontal movement of the hillside landslide which is:

[0054]

[0055] Step 3. Horizontal movement of the mountainous area surface Solve;

[0056] Substitute Equation (5) into Equation (1) to obtain the horizontal movement of the mountainous area surface

[0057]

[0058] Step 4. Horizontal deformation of the mountainous area surface Solve;

[0059] Take the first derivative of the horizontal movement of the mountainous area surface obtained in Step 3 to obtain the horizontal deformation of the mountainous area surface The expression is:

[0060]

[0061] Step 5. Predict the development location of ground fissures: Collect and analyze the stratigraphic and geological data of the prediction area, obtain the values of the parameters in Equation (4) and substitute them into Equations (6) and (7) to calculate the predicted value of the horizontal movement of the mountainous area surface and the horizontal deformation of the mountainous area surface The predicted value is obtained and the change curve is plotted; then, in combination with the change curve, the peak points are marked to determine the development location of the ground fissure.

[0062] Preferably, in step 5, the formation geological data includes formation lithology, geological structure, engineering geology, hydrogeology, and coal seam occurrence data.

[0063] Preferably, in step 5, the formation geological data is obtained from the preliminary design specification of the mine, the special safety chapter of the mine, the geological exploration report of the mine, the mining engineering plan, the mining engineering profile, the surface and underground comparison map, and the mining operation specification of the working face.

[0064] Preferably, in step 5, the parameters in formula (4) are the surface feature coefficient T (x) , the mountain influence function J (x) , the maximum subsidence value W of flat ground under the same mining geological conditions max , the maximum height h of the mountain m , the difference h between the mining depth of a certain point x on the surface of the slope and the minimum mining depth within the mining range (x) , the mining depth H of a certain point x on the surface of the slope (x) , the slope influence function p (x) , the subsidence value W of a certain point x on the surface of flat ground under the same mining geological conditions (x) , the surface profile dip angle α of a certain point x on the surface (x) , the mining influence radius r, the average mining depth H within the mining range, the mining influence angle β, and the parameters A, B, C, and D of the mountain slip amount;

[0065] Preferably, in step 5, the values of the parameters in formula (4) are:

[0066] The surface feature coefficient T (x) is related to the thickness and properties of the overburden layer, and the value ranges from 0.4 to 2.0; specifically: for the overburden layer with a thickness less than 2m and vegetation, the value ranges from 0.4 to 0.8; for the overburden layer with a thickness less than 2m and no vegetation, the value ranges from 0.8 to 1.2; for the overburden layer with a thickness of 2 - 5m, the value ranges from 1.0 to 1.4; for the overburden layer with a thickness greater than 5m, the value ranges from 1.4 to 2.0;

[0067] The parameters A, B, C, and D of the mountain slip amount are taken as π / 100, π / 3, π / 2, and π respectively;

[0068] The mining influence radius r = H / tanβ, the average mining depth H within the mining range is obtained from the geological exploration report of the mine, and the mining influence angle β refers to the angle between the connection line of the boundary of the mining influence area and the inflection point of the subsidence curve and the horizontal line, and is obtained from the geological exploration report of the mine;

[0069] The value of the mountain influence function J (x) is calculated according to the values of the mining influence radius r, the parameters A and B of the mountain slip amount;

[0070] The maximum subsidence value W of flat ground under the same mining geological conditions max is obtained through numerical simulation and theoretical calculation;

[0071] The maximum height h of the mountain body m is obtained by combining the mining engineering plan and the mine geological exploration report;

[0072] The difference h between the mining depth of a certain point x on the ground surface of the slope body and the minimum mining depth within the mining range (x) is obtained by combining the mining engineering plan and the mine geological exploration report;

[0073] The mining depth H of a certain point x on the ground surface of the slope body (x) is obtained by combining the mining engineering plan and the mine geological exploration report;

[0074] The slope influence function p (x) is obtained by calculating based on the mining influence radius r and the values of the parameters C and D of the mountain area sliding amount;

[0075] The subsidence value W of a certain point x on the ground surface of flat ground under the same mining geological conditions (x) is obtained through numerical simulation and theoretical calculation;

[0076] The ground surface profile dip angle α of a certain point x on the ground surface (x) is obtained according to the mining engineering profile diagram.

[0077] Example 1:

[0078] This mine is located in the southwestern part of the Daweiling Anticline in Anshun City, Guizhou Province. The well field is surrounded by faults F1, F2, F3, and F5. There are few faults in the well field. The structural form of the well field is a monoclinic structure, and the complexity belongs to the simple type. There are 3 coal seams that can be mined in the well field, namely the C0, C8, and C9 coal seams. The average layer spacing between the C8 and C9 coal seams is 18m. The 8912 working face is the second working face in the first mining area, adjacent to the upper working face in the west of the three-panel area, bounded by the track return air connection lane in the south, and adjacent to the main return air inclined shaft in the east. The strike length of the working face is 1000m, and the dip length is 190m. The working face mines the C9 coal seam, with a coal seam thickness of 2.0m, a maximum coal seam burial depth of 220m, and a minimum burial depth of 104m. The overlying strata of the coal seam are mainly limestone, argillaceous sandstone, and siltstone, and the floor is mainly siltstone or siltstone claystone. The ground surface is a medium-low mountain landform, and the ground surface slope is a composite slope body. The surface soil layer is yellowish-brown or brownish-yellow clay, with a thickness of about 4m.

[0079] Step 1: Collect formation geological data

[0080] (1) Lithology of the strata: The coal-bearing strata are the Longtan Formation of the Permian System, which is composed of fine sandstone, siltstone, clayey siltstone, chert limestone and coal seams alternatingly.

[0081] (2) Geological structure: Generally, it is a broad and gentle anticline structure along the strike. During the driving of the open-off cut of the 8912 working face, a normal fault was revealed when driving to 86 meters. Its occurrence: the strike is 42°, the dip is 72°, and H = 3.46m.

[0082] (3) Coal seam occurrence: The coal seam mined in the 8912 working face is the C9 coal seam, with a thickness of 1.3 - 2.2m and an average thickness of 2.0m. The coal seam is relatively stable, with a simple structure. There is no parting in the coal seam within the working face. The macroscopic coal-rock characteristics are bright - semi-bright type, mainly bright coal, followed by vitrain and dull coal, powdery - massive, banded structure. There are soft partings developed in the coal seam, and the coal seam hardness is relatively small.

[0083] (4) Overlying rock lithology: The basic roof is limestone, with a thickness of 3.55m; the immediate roof is argillaceous sandstone or siltstone, with a thickness of 2.21 - 7.76m and an average thickness of 4.9m. It has horizontal bedding, locally contains calcareous components, and the firmness coefficient f = 4 - 6; there is no false roof. The immediate floor is siltstone or siltstone claystone, with a thickness of 4.5m.

[0084] (5) Hydrogeology: The southern part is the Pingqiao Valley, and the Pingqiao River is the main surface water body in the mining area. The karst fissure aquifer of the Changxing Formation and the layered fissure aquifer of the Longtan Formation are the direct aquifers. The hydrogeological exploration type is medium. It is estimated that the maximum water inflow during the coal mining process of the working face is 10m 3 / h.

[0085] (6) Gas, coal dust, spontaneous combustion and ground temperature: According to the gas identification results, the C9 coal seam is a coal and gas outburst coal seam. Dynamic phenomena have occurred during the mining and excavation process, and coal and gas outbursts have occurred during the driving process. The coal dust has no explosion hazard. The C9 coal seam is a coal seam that is not prone to spontaneous combustion, and there is no high-temperature heat hazard.

[0086] Step 2: Calculation of the predicted values of horizontal movement and horizontal deformation on the mountain surface

[0087] The strike length of the 8912 working face is about 1000 m, the dip length is 190 m, the slope of the overlying surface of the working face is 6° - 54.7°, and the thickness of the surface soil layer is about 4 m of clay. The maximum burial depth of the coal seam is 220 m, and the minimum burial depth is 104 m. According to the actual excavation and mining engineering of the 8912 working face, the predicted parameter values for mining subsidence are as follows: the surface characteristic coefficient is taken as 1.2; the influence function of slope loading is taken as 1.6; according to the surface undulation, it is taken as 110 m; according to the surface undulation, it is taken as 0 - 110 m; according to the surface undulation, it is taken as 110 - 220 m; according to past experience, it is taken as 2.5; according to the change of the working face burial depth, it is taken as 110 - 220 m; it is taken as 44 - 88 m; it is taken as 0.8. Substituting the above data into equations (6) and (7), the predicted value of the horizontal movement of the mountainous surface and the predicted value of the horizontal deformation of the mountainous surface are obtained. From Figure 2 and Figure 3 analysis, it can be seen that the overall change trend of the predicted value of the horizontal movement of the mountainous surface and the predicted value of the horizontal deformation of the mountainous surface is consistent with the measured value.

[0088] Step 3: Prediction of the development location of ground fissures

[0089] (1) Along the strike of the working face from 0 to 150 m: The predicted value of the horizontal movement of the mountainous surface is 137 - 313 mm, and the predicted value of the horizontal deformation of the mountainous surface is -14.4 - -4.3 mm / m. The predicted value of the horizontal deformation of the mountainous surface is negative, indicating that the overall surface covered along the strike of the working face from 0 to 150 m is in a compressive state, which is not conducive to the development of ground fissures. Through on-site investigation, it is found that there are very few ground fissures developed on the surface covered along the strike of the working face from 0 to 150 m. Due to the mining subsidence effect, the slope body has a sliding deformation in the downhill direction, so the horizontal movement of the mountainous surface is positive.

[0090] (2) Along the strike of the working face from 180 to 390 m: The predicted value of the horizontal movement of the mountainous surface within this range continues to increase, and the maximum value is -781 mm. And the horizontal deformation of the mountainous surface The predicted value changes from negative to positive, with an average value of 7.18 mm / m, indicating that the overall surface covered along the working face strike from 180 to 390 m changes from a compressed state to a tensile state. The surface in this area is a steep slope with a large gradient, and the maximum gradient is 54.7°. Due to the combined action of mining subsidence and steep slope sliding on the surface, it is conducive to the development of ground fissures. Through on-site inspection and measurement, three tensile ground fissures LS1, LS2, and LS3 are developed on the surface at this location. The development width of the ground fissures is 0.58 - 0.73 m, and the drop is 0.62 - 0.97 m.

[0091] (3) Along the working face strike from 420 to 540 m: The surface covered along the working face strike from 420 to 540 m is a valley with a gentle slope and underdeveloped gullies. The horizontal movement of the mountain surface has a predicted maximum value of 487 mm and a minimum value of 178 mm. The horizontal deformation of the mountain surface has a predicted value that changes from positive to negative, with a predicted value of -5.89 to -12.78 mm / m. This indicates that the valley as a whole is in a compressed state, which is not conducive to the development of ground fissures. Through on-site inspection, two stepped ground fissures are developed on the gentle slopes on both sides of the valley. The development width and drop of the stepped ground fissure TJ1 are 0.07 m and 0.18 m respectively, and the development width and drop of the stepped ground fissure TJ2 are 0.06 m and 0.22 m respectively.

[0092] (4) Along the working face strike from 570 to 810 m: Along the strike of the overlying surface of the working face, the surface gradient continues to increase. Among them, the surface gradient suddenly increases along the working face strike from 570 to 600 m, increasing from 6° to 26.1°. The horizontal deformation of the mountain surface has a predicted value of 0.33 to 5.47 mm / m, and the overall surface covered within this range is in a tensile state. The predicted values of the horizontal movement of the mountain surface at the observation points Z19, Z26, and Z27 are positive, and the predicted values of the horizontal movement of the mountain surface at other points are negative. The surface near 570 m, 780 m, and 810 m along the working face strike is conducive to the development of ground fissures. Combining the results of on-site inspection, tensile ground fissures LS4, LS5, and LS6 are developed on the surface near 570 m, 780 m, and 810 m along the working face strike respectively.

[0093] (5) Along the working face strike from 840 to 900 m: The predicted maximum value of the horizontal movement of the mountain surface within this range is 57 mm, and the predicted maximum value of the horizontal deformation of the mountain surface is 1.82 mm / m. It can be seen that the influence of coal seam mining on the surface at this location is relatively small. Through on-site inspection, only one stepped ground fissure TJ5 is developed on the surface.

[0094] What is not described in the present invention applies to the prior art.

Claims

1. A method for predicting the location of ground fissures in shallow coal seam mining in mountainous areas, characterized in that: The method comprises the following steps: Step 1: Decomposition of horizontal movement deformation of mountain surface: Decompose the horizontal movement deformation of mountain surface into horizontal movement deformation of flat land under the same mining geological conditions and horizontal movement deformation of slope sliding under the same mining geological conditions; Among them, the horizontal movement of the mountain surface It is expressed as: In formula (1), It represents the horizontal movement of flat land under the same mining geological conditions. It represents the horizontal movement of slope sliding under the same mining geological conditions; x represents a point on the ground surface; Horizontal deformation of mountain surface It is expressed as: In formula (2), It represents the horizontal deformation of flat land under the same mining geological conditions. Represents the horizontal deformation of slope sliding under the same mining geological conditions; Step 2: Horizontal movement of hillside slide Solution; According to the superposition principle, the vertical displacement of the slope slip at a point x on the surface is calculated and horizontal movement of hillside slides Horizontal movement of hillside slide and vertical movement of hillslides The movement S that constitutes the slope slide (x) , as shown in formula (3): In formula (3), the vertical displacement of the slope sliding is Horizontal movement of hillside slide δ is the displacement S of the slope sliding (x) The inclination angle; Then calculate the movement S of the slope sliding according to formula (3): (x) ; Then, based on the existing surface subsidence observation data, the movement S of the slope sliding is obtained (x) The expression of is shown in formula (4): In formula (4), T (x) is the surface characteristic coefficient, J (x) is the mountain influence function, W max h is the maximum subsidence value of flat land under the same mining geological conditions; m is the maximum height of the mountain; h (x) is the difference between the mining depth of a certain point x on the surface of the slope and the minimum mining depth within the mining range; H (x) is the mining depth at a certain point x on the surface of the slope; p (x) is the slope influence function, W (x) is the subsidence value of a point x on the surface of flat ground under the same mining geological conditions; α (x) is the surface profile inclination angle of a certain point x on the surface; r is the mining influence radius, r = H / tanβ, H is the average mining depth within the mining range, β is the mining influence angle; A, B, C, D represent the parameters of the slip amount in mountainous areas; Substituting equation (4) into equation (3), we can obtain the horizontal displacement of the slope sliding: for: Step 3: Horizontal movement of mountain surface Solution; Substituting equation (5) into equation (1), we can obtain the horizontal displacement of the mountain surface: Step 4: Horizontal deformation of mountain surface Solution; The horizontal movement of the mountain surface obtained in step 3 Calculate the first-order derivative to obtain the horizontal deformation of the mountain surface Its expression is: Step 5: Predict the location of ground fissures: Collect and analyze the stratigraphic geological data of the prediction area, obtain the values ​​of the parameters in formula (4) and substitute them into formulas (6) and (7) to calculate the horizontal movement of the mountain surface. Predicted values ​​and horizontal deformation of mountain surface The predicted value is obtained and a change curve is drawn; then the peak point is marked based on the change curve to determine the location of ground fissure development.

2. The method for predicting the location of ground fissures in shallow coal seam mining in mountainous areas according to claim 1 is characterized in that: In step 5, the stratigraphic geological data include stratigraphic lithology, geological structure, engineering geology, hydrogeology and coal seam occurrence data.

3. The method for predicting the location of ground fissures in shallow coal seam mining in mountainous areas according to claim 1 or 2, characterized in that: In step 5, the stratigraphic geological data are obtained from the preliminary mine design instructions, mine safety special report, mine geological survey report, mining engineering plan, mining engineering profile, upper and lower well comparison map and working face mining instructions.

4. The method for predicting the location of ground fissures in shallow coal seam mining in mountainous areas according to claim 1 is characterized in that: In step 5, the parameter in equation (4) is the surface characteristic coefficient T (x) , mountain influence function J (x) , the maximum subsidence value W of flat land under the same mining geological conditions max 、Maximum height of mountain h m , the difference h between the mining depth at a certain point x on the surface of the slope and the minimum mining depth within the mining range (x) , the mining depth H at a certain point x on the surface of the slope (x) , slope influence function p (x) , the subsidence value W of a point x on the surface of flat ground under the same mining geological conditions (x) , the surface profile inclination angle α at a certain point x on the surface (x) , mining influence radius r, average mining depth H within the mining range, mining influence angle β and parameters A, B, C and D of slip amount in mountainous areas.

5. The method for predicting the location of ground fissures in shallow coal seam mining in mountainous areas according to claim 1 or 4, characterized in that: In step 5, the values ​​of the parameters in formula (4) are: Surface characteristic coefficient T (x) It is related to the thickness and properties of the topsoil layer and ranges from 0.4 to 2.0; The parameters of slip in mountainous areas are A = π / 100, B = π / 3, C = π / 2, and D = π; The mining influence radius r = H / tanβ, the average mining depth H within the mining range is obtained from the mine geological survey report, and the mining influence angle β is obtained from the mine geological survey report; Mountain influence function J (x) The value of is calculated based on the mining influence radius r and the values ​​of the parameters A and B of the mountain slip amount; The maximum subsidence value W of flat land under the same mining geological conditions max The value of is obtained through numerical simulation and theoretical calculation; Maximum height of the mountain h m The value of is obtained by combining the mining engineering plan and the mine geological survey report; The difference h between the mining depth at a certain point x on the slope and the minimum mining depth within the mining range (x) The value of is obtained by combining the mining engineering plan and the mine geological survey report; The mining depth H at a certain point x on the slope (x) The value of is obtained by combining the mining engineering plan and the mine geological survey report; Slope influence function p (x) The value of is calculated based on the mining influence radius r, the values ​​of the parameters C and D of the mountain slip amount; The subsidence value W of a point x on the surface of flat ground under the same mining geological conditions (x) It is obtained through numerical simulation and theoretical calculation; The inclination angle α of the surface profile at a point x on the surface (x) Derived from the cross-section drawing of the mining project.

6. The method for predicting the location of ground fissures in shallow coal seam mining in mountainous areas according to claim 5, characterized in that: In step 5, the surface characteristic coefficient T (x) The specific values ​​are: for topsoil with a thickness of less than 2m and with vegetation, the value is 0.4-0.8; for topsoil with a thickness of less than 2m and without vegetation, the value is 0.8-1.2; for topsoil with a thickness of 2-5m, the value is 1.0-1.4; for topsoil with a thickness of more than 5m, the value is 1.4-2.0.

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