Method for predicting long-term deformation of multi-seam goaf on mountainous area surface

Abstract

The invention relates to a long-term deformation prediction method for a mountainous area surface multi-coal-seam goaf. The method comprises the following steps: establishing a long-term deformation prediction method for a horizontal surface single-coal-seam goaf; obtaining a mountain area surface single coal seam goaf long-term deformation prediction method; calculating the influence range of the repeated mining area of the earth surface points according to the marked different earth surface points, and calculating the long-term deformation of the lithology single-coal-seam goaf of different stratums of the mountainous area earth surface; in the multi-coal-seam goaf with different stratum lithology on the mountainous area surface, the superposition calculation of the subsidence coefficient of the multi-coal-seam goaf and the main influence angle tangent value selected by different stratum lithology is corrected, and meanwhile, the classification standard and calculation parameter adjustment method under different intervals and overlapping forms of an upper coal seam and a lower coal seam are provided; and establishing a long-term deformation prediction model of the mountain surface multi-coal-seam goaf, and predicting the long-term deformation of the mountain surface multi-coal-seam goaf. According to the invention, the applicability and accuracy of the prediction model are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal seam residual deformation prediction, and in particular is a method for predicting long-term deformation of multi-coal seam goaf areas on the surface of a mountainous area. Background Art

[0002] In existing technologies, such as remote sensing image analysis, numerical simulation, and machine learning, there are great difficulties in predicting the mining of multiple coal seams with different lithologies on the surface of mountainous areas. In actual engineering conditions, the geological conditions are relatively complex, and existing technologies have obvious deficiencies in the field of mining subsidence prediction that comprehensively considers multiple factors, especially in the long-term deformation problem of mountainous surface, multi-coal seam mining, and different stratum lithologies. Specifically, existing models can usually only handle a single factor or specific geological conditions, and lack a mature prediction model that can comprehensively consider multiple factors. For example, the prediction method of residual deformation of goaf areas on the surface of mountainous areas and the prediction method of long-term deformation of overburden in goaf areas of multiple coal seams only consider mountainous surface mining or multi-coal seam mining, and fail to effectively deal with the common complex situations in actual engineering. This limitation leads to the lack of accuracy of the calculation results of the long-term deformation problem of mining multiple coal seams with different lithologies on the surface of mountainous areas, which in turn affects the reliability of engineering design, construction management, and safety assessment. In addition, the applicability of traditional prediction methods under the conditions of mining multiple coal seams with different lithologies on the surface of mountainous areas is poor, and they often fail to meet the actual engineering needs, which may lead to waste of resources and damage to the environment, and even cause safety accidents in extreme cases. Under the influence of factors such as complex topography and landforms, the surface movement and deformation caused by underground mining of coal resources in mountainous terrain has a more serious impact on surface buildings (structures) than in plain areas. At the same time, in terms of the residual deformation of the surface in old goafs, mountainous areas with relatively complex topography and landforms will also have a certain degree of influence on the residual deformation. Repeated mining of multiple coal seams will cause more severe surface subsidence and more obvious surface damage. In addition, the influence of surface movement deformation and residual deformation is more complicated due to different stratum lithology. Therefore, the research on long-term deformation of multiple coal seams with different stratum lithology on the surface of mountainous areas is immature. Summary of the invention

[0003] In order to solve the existing technical problem of long-term deformation of multi-coal seam goafs with different strata and lithology on the surface of mountainous areas, the present invention provides a method for predicting long-term deformation of multi-coal seam goafs on the surface of mountainous areas. The prediction model of equivalent variable mining thickness, the influence of mining slip and different lithology in mountainous areas is used to correct the sinking coefficient and the tangent value of the main influencing angle in mining multi-coal seams with different strata and lithology, thereby improving the applicability and accuracy of the prediction model. The problem of long-term deformation of multi-coal seam goafs with different strata and lithology on the surface of mountainous areas is solved.

[0004] The present invention is achieved by adopting the following technical solutions:

[0005] A method for predicting long-term deformation of multi-coal seam goaf areas on the surface of mountainous areas comprises the following steps:

[0006] Based on the probability integral method of equivalent variable mining thickness and the Knothe time function that describes the relationship between surface subsidence and time, a long-term deformation prediction method for goaf areas of single coal seams on a horizontal surface is established; by zoning the goaf areas, the surface movement deformation value caused by flat ground mining and the mountain sliding amount are superimposed to predict the surface mining movement deformation value in mountainous areas, and the influence of mining sliding in mountainous areas is calculated. Then, the long-term deformation prediction method for goaf areas of single coal seams on a horizontal surface is used, and the model formula of the probability integral method based on equivalent variable mining thickness and the Knothe time function are substituted into the surface residual deformation prediction model in mountainous areas, and the long-term deformation prediction method for goaf areas of single coal seams on a horizontal surface is obtained. Method; divide the stratum lithology by lithology type, calculate the intersection of the inclination line and the surface in sections according to the main influencing angles of different stratum lithologies, and calculate the long-term deformation of the single coal seam goaf area with different stratum lithologies on the surface of the mountainous area according to the influence range of the different calculated surface points; in the multi-coal seam goaf area with different stratum lithologies on the surface of the mountainous area, correct the subsidence coefficient of the multi-coal seam goaf area and the superposition calculation of the tangent value of the main influencing angle of different stratum lithologies, and propose classification standards and calculation parameter adjustment methods under different spacings and overlapping forms between upper and lower coal seams; establish a long-term deformation prediction model for multi-coal seam goaf areas on the surface of mountainous areas, and predict the long-term deformation of multi-coal seam goaf areas on the surface of mountainous areas.

[0007] Preferably, establishing a method for predicting long-term deformation of a single coal seam goaf in a horizontal terrain includes: obtaining a probability integral method model of equivalent variable mining thickness according to a calculation formula for any point on the ground based on the probability integral method of equivalent variable mining thickness, and combining the symmetry of the goaf.

[0008] Preferably, the method for obtaining the long-term deformation prediction of the single coal seam goaf area on the mountainous area topography includes: obtaining at least one landform data in the target mountainous area surface based on the division results of the surface landforms of different mountainous areas; obtaining the initial residual deformation value of the target mountainous area surface using the residual deformation value and the target landform data; constructing a long-term deformation prediction model of the single coal seam goaf area on the mountainous area topography of the target mountainous area surface according to the corrected initial residual deformation value and the initial mountainous area surface residual deformation prediction model, so as to use the long-term deformation prediction model of the single coal seam goaf area on the mountainous area topography to perform the long-term deformation prediction of the goaf area on the target mountainous area surface.

[0009] Preferably, the long-term deformation prediction model for single coal seam goaf areas in mountainous terrain includes: at least one of a residual subsidence calculation formula, a concave landform residual horizontal movement calculation formula, and a convex landform residual horizontal movement calculation formula.

[0010] Preferably, the influence range of the different calculated surface points includes: determining the intersection of the inclined straight line and the surface through the main influence angles of different stratum lithologies.

[0011] Preferably, the correction of the subsidence coefficient includes: classifying the repeated mining of multiple coal seams according to the position of the original upper coal seam after the mining of the lower coal seam, and adjusting the subsidence coefficient parameters according to the repeated mining of the overburden rock properties.

[0012] Preferably, the calculation of the distance between the upper coal seam and the lower coal seam includes: classifying the upper coal seam according to its location, and adjusting the sinking parameters under different circumstances accordingly; calculating the height of the collapse zone and the fault zone after the lower coal seam is mined according to the empirical formula in the specification, and determining the original position of the upper coal seam by comparing the relationship between the distance between the upper coal seam and the lower coal seam and the height of the collapse zone and the height of the fault zone.

[0013] Preferably, the classification criteria under the overlapping form include: according to the different positions of the upper coal seam and the lower coal seam, by judging whether the relative positions of the upper coal seam and the lower coal seam produce repeated mining areas or the positions of the repeated mining areas are different, the repeated mining situations of multiple coal seams are classified, and the repeated mining of repeated mining areas is judged to adjust the subsidence coefficient and main influencing angle parameters.

[0014] Preferably, the calculation parameter adjustment method includes: selecting parameter adjustment according to different positions of the upper coal seam and the lower coal seam and whether repeated mining occurs in the area classification, and determining the long-term deformation prediction calculation method of the single coal seam goaf area in the mountainous area of ​​each upper coal seam and the lower coal seam:

[0015] For areas that have not been repeatedly mined, they are calculated according to whether they belong to the upper coal seam or the lower coal seam affected area; according to the long-term deformation prediction method of single coal seam goaf areas with different strata and lithology on the surface of mountainous areas;

[0016] For areas where repeated mining occurs, the upper coal seam is calculated using the long-term deformation prediction method for goafs of single coal seams with different strata and lithologies on the surface of mountainous areas; the lower coal seam is calculated using the long-term deformation prediction method for goafs of single coal seams with different strata and lithologies on the surface of mountainous areas. The subsidence coefficient and tangent value of the main influencing angle of the lower coal seam are corrected, and the calculation results of the upper and lower coal seams are superimposed to obtain the result of the repeated mining area.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the present invention combines the method for predicting long-term deformation of single coal seam mining in mountainous areas and long-term deformation of overburden in multi-coal seam goafs, and can comprehensively consider multiple key factors such as mountainous surface, different stratum lithology, multi-coal seam mining and long-term deformation to construct a prediction model. It provides a solution to the problem of long-term deformation of multi-coal seam mining under different stratum lithology conditions on the mountainous surface and long-term deformation of multi-coal seam mining under different lithology conditions on the mountainous surface. This will significantly improve the safety and effectiveness of mining subsidence projects, reduce economic losses and environmental impacts caused by inaccurate predictions, and provide solid technical support for the sustainable development and management of resources.

[0018] Compared with single coal seam mining, multi-coal seam mining on the surface of mountainous areas corrects the sinking coefficient and the tangent value calculation parameters of the main influence angle (the angle between the straight line of the continuous main influence range boundary and the mining boundary and the horizontal line), and links the long-term deformation of single coal seam mining on the surface of mountainous areas with the long-term deformation of multi-coal seam mining on the surface of mountainous areas. For the main influence angle determined by different stratum lithology, a long-term deformation prediction method for multi-coal seam mining with different stratum lithology on the surface of mountainous areas is established. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the influence range relationship of different stratum lithologies in the long-term deformation prediction method of multi-coal seam goaf areas on the surface of mountainous areas according to the present invention.

[0020] Figure 2 It is a schematic diagram of the influence range of the lower coal seam mining collapse zone of the long-term deformation prediction method of multi-coal seam goaf areas on the surface of mountainous areas of the present invention.

[0021] Figure 3 It is a schematic diagram of the influence range of the lower coal seam mining fault zone of the long-term deformation prediction method of multi-coal seam goaf areas on the surface of mountainous areas of the present invention.

[0022] Figure 4 It is a schematic diagram of the influence range of the lower coal seam mining bending zone of the long-term deformation prediction method of multi-coal seam goaf areas on the surface of mountainous areas of the present invention.

[0023] Figure 5 It is a schematic diagram of the main influencing angles of the stratum lithology of the long-term deformation prediction method of the multi-coal seam goaf area on the surface of the mountain area according to the present invention.

[0024] Figure 6 It is a schematic diagram of correction of the main influencing angles of the disturbed upper coal seam in the long-term deformation prediction method of multi-coal seam goaf areas on the surface of mountainous areas according to the present invention.

[0025] Figure 7 It is a schematic diagram of the area where repeated mining does not occur in the lower coal seam and the upper coal seam of the long-term deformation prediction method of the multi-coal seam goaf area on the surface of the mountain area of ​​the present invention.

[0026] Figure 8 The lower coal seam and upper coal seam positions of the long-term deformation prediction method for multi-coal seam goaf areas on the surface of mountainous areas of the present invention are schematic diagrams of areas where repeated mining occurs.

[0027] Fig. 9 Another schematic diagram of the method for predicting long-term deformation of multi-coal seam goaf areas on the surface of mountainous areas according to the present invention is the location of the lower coal seam and the upper coal seam as the area where repeated mining occurs.

[0028] Fig.10 This is another schematic diagram of the area where repeated mining occurs, with the lower coal seam and the upper coal seam located in the long-term deformation prediction method for multi-coal seam goaf areas on the surface of mountainous areas of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0030] The long-term deformation prediction method of multi-coal seam goaf area on the surface of mountainous area is applied in the model construction stage, wherein the method comprises the following steps:

[0031] S1. Based on the probability integral method of equivalent variable mining thickness and the Knothe time function that describes the relationship between surface subsidence and time, a method for predicting long-term deformation of single coal seam goaf in horizontal ground is established;

[0032] The method for predicting the long-term deformation of the goaf of a single coal seam on the horizontal ground includes: according to the calculation formula of the probability integral method based on the equivalent variable mining thickness at any point on the ground, and combined with the symmetry of the goaf, the probability integral method model of the equivalent variable mining thickness is obtained. The Knothe time function is used as a time function in the prediction of mining subsidence to describe the dynamic sinking process of the surface.

[0033] S2. By zoning the goaf, the surface movement deformation value caused by flat ground mining and the amount of mountain sliding are superimposed to predict the surface mining movement deformation value in the mountainous area, and the influence of mining sliding in the mountainous area is calculated. Then, the long-term deformation prediction method of the goaf of single coal seams on the horizontal ground is used, and the probability integral method model formula based on equivalent variable mining thickness and Knothe time function are substituted into the residual deformation prediction model of the mountainous area surface, and the long-term deformation prediction method of the goaf of single coal seams on the horizontal ground is obtained;

[0034] Preferably, the method for obtaining the long-term deformation prediction of the single coal seam goaf area on the mountainous terrain includes: obtaining at least one landform data in the target mountainous surface based on the division results of the surface landforms of different mountainous areas; obtaining the initial residual deformation value of the target mountainous surface using the residual deformation value and the target landform data; constructing a long-term deformation prediction model for the single coal seam goaf area on the mountainous terrain of the target mountainous surface according to the corrected initial residual deformation value and the initial mountainous surface residual deformation prediction model, so as to use the long-term deformation prediction model for the single coal seam goaf area on the mountainous terrain to perform the long-term deformation prediction of the goaf area on the target mountainous surface.

[0035] The long-term deformation prediction model for single coal seam goaf areas in mountain terrain includes: at least one of a residual subsidence calculation formula, a concave landform residual horizontal movement calculation formula, and a convex landform residual horizontal movement calculation formula;

[0036] The goaf is refined and the variable mining thickness probability integral method model is constructed by superposition, as shown in the following formula:

[0037] U0(x)=brI0(x)# (3)

[0038] W0(x) is the residual settlement value at a certain point on the surface; h n is the height of the left hollow area block, x is the horizontal coordinate of any point on the surface; s is the horizontal coordinate of the mining unit; AC, CD, DB are the integration intervals, m′ and m1 represent the residual reactivatable thickness of the boundary area and the middle area respectively; W e (x) is the unit subsidence caused by unit mining; m is the mining thickness; I0(x) is the residual inclination; I b1 ,I z and I bz are the residual inclination of the left hollow area, the middle compaction area, and the right hollow area; U0(x) is the residual horizontal displacement value; n is the block number of the left hollow area, which is 1, 2, 3 from left to right...; m and m1 are the residual activation thickness of the mining thickness and the middle area, respectively. n′ is the block height of the right hole area, n′ represents the block serial number of the right hole area, n0′ is the number of small blocks in the right hole area; l0 is the length of the hole area; ds is the differential of s and can be understood as a "differential", that is, a very small section of the independent variable s, or a very small section on the horizontal axis, but it is not equal to zero.

[0039] The model formula for predicting surface mining subsidence in mountainous areas can be, but is not limited to:

[0040] W′(x)=W(x)+D x P(x)W(x)tan 2 α# (4)

[0041] U′(x)=U(x)+D x P(x)W(x)tanα(concave topography)# (5)

[0042] U′(x)=U(x)-D x P(x)W(x)tanα(convex topography)# (6)

[0043] The model formula for predicting residual deformation of mountainous surface can be, but is not limited to, the following:

[0044] W′0(x)=W0(x)+D x P(x)W0(x)tan 2 α# (7)

[0045] U′0(x))=U0(x)+D x P(x)W0((x)tanα(concave topography)# (8)

[0046] U′0(x))=U0(x)-Dx P(x)W0(x)tanα(convex topography)# (9)

[0047] Formula (1), formula (2) and formula (3) are substituted into formula (7)-(9), and Knothe time function is introduced to characterize the relationship between residual deformation and time. The long-term deformation prediction formula of single coal seam goaf in mountainous terrain is:

[0048]

[0049]

[0050] Where W′0(x, t) is the residual settlement value at point x on the mountain surface at time t; U′0(x, t) is the residual horizontal displacement value at point x on the mountain surface at time t. e (x) is the unit subsidence caused by unit mining; h n is the block height of the left hole area; D x is the surface characteristic coefficient of the mountain area; P(x) is the slip influence function; α x is the inclination angle of the topographic trend surface of the smoothed surface point;

[0051] Topographic trend surface inclination angle α x and mountain surface characteristic coefficient D x The value of: a positive slope or reverse slope with a slope change of no more than 5°, smoothing a terrain trend surface inclination angle α x , mountain surface characteristic coefficient D x According to the values ​​of concave and convex landforms in Table 1, there is a sudden change near the positive and negative slope change points and the concave and convex landform change points, and the image is faulted. Here, the nonlinear least squares method or polynomial is used to fit a smooth arc curve such as a hyperbola, ellipse or parabola to solve the problem of this sudden change, or a simple correction method is used to calculate the inclination angle α of the terrain trend surface at the positive and negative slope change points. x The inclination of one trend surface is uniformly transitioned to another trend surface, solving the mutation problem that appeared earlier; at the point where the concave-convex landform changes, the surface characteristic coefficient D of the mountain area x The surface characteristic coefficient of one mountain area transitions evenly to the surface characteristic coefficient of another mountain area.

[0052] S3. Calculate the intersection of the inclination line and the surface in sections according to the main influencing angles of different strata and lithologies, and calculate the long-term deformation of the single coal seam goaf area with different strata and lithologies on the surface of the mountainous area according to the influence range of different calculated surface points;

[0053] Preferably, the influence range of the different calculated surface points includes: determining the intersection of the inclined straight line and the surface through the main influence angles of different stratum lithologies. The repeated mining area refers to the area affected by both the upper and lower coal seams after mining. The influence range refers to the section of the surface above the coal seam that is affected by the mining of a certain section of the coal seam, which is the main influence radius r parameter.

[0054] In the prediction calculation of long-term deformation of single coal seam goaf in mountainous area, different lithologies of underground strata are taken into consideration, and the influence radius r is substituted into the calculation formula of long-term deformation of single coal seam goaf with different lithologies of strata on the surface of mountainous area, and the prediction method of long-term deformation of single coal seam goaf with different lithologies of strata on the surface of mountainous area is obtained.

[0055] S4. In the multi-coal seam goaf with different stratum lithology on the surface of mountainous areas, the subsidence coefficient of the multi-coal seam goaf and the superposition calculation of the tangent value of the main influencing angle of different stratum lithology selection are corrected, and the classification standard and calculation parameter adjustment method under different spacing and overlapping forms of upper and lower coal seams are proposed;

[0056] S5. Establish a long-term deformation prediction model for multi-coal seam goaf areas on the surface of mountainous areas to predict the long-term deformation of multi-coal seam goaf areas on the surface of mountainous areas.

[0057] After mining multiple coal seams such as the upper coal seam and the lower coal seam, the lithology prediction of different strata on the surface of mountainous areas includes:

[0058] ①. According to the calculation formula of the long-term deformation of the goaf area of ​​a single coal seam in different strata on the surface of mountainous areas, the influence of the upper coal seam on the surface is calculated and the repeated mining area is determined;

[0059] ②. If there is no repeated mining area, calculate the impact of the lower coal seam on the surface according to the calculation formula of the long-term deformation of the goaf area of ​​a single coal seam in different strata on the surface of the mountainous area;

[0060] ③. If repeated mining areas appear, the subsidence coefficient and the tangent value of the main influencing angle of the lower coal seam are corrected, and the impact of the lower coal seam on the surface is calculated. Then the long-term deformation calculation formula of the goaf of a single coal seam with different strata and lithology on the surface of the mountainous area is superimposed to obtain the long-term deformation calculation formula of the goaf of multiple coal seams with different lithology on the surface of the mountainous area.

[0061] ④. For areas affected by repeated mining of the lower coal seam and the upper coal seam, the types of situations in the areas of repeated mining are analyzed based on the different locations of the upper coal seam and the lower coal seam.

[0062] The calculation model for predicting long-term deformation of goafs of multiple coal seams with different stratum lithologies on the surface of mountainous areas: The upper coal seam is obtained according to the calculation formula for long-term deformation of goafs of single coal seams with different stratum lithologies on the surface of mountainous areas. The subsidence coefficient and the tangent value of the main influencing angle are corrected on the calculation formula for long-term deformation of goafs of multiple coal seams with different stratum lithologies on the surface of mountainous areas to obtain the calculation formula for the lower coal seam. The superposition of the subsidence coefficient and the tangent value of the main influencing angle is the calculation formula for long-term deformation of goafs of multiple coal seams with different stratum lithologies on the surface of mountainous areas.

[0063] The parameter correction of the subsidence coefficient of the multi-coal seam goaf area includes: correcting the terrain trend surface inclination angle on the mountain surface, dividing the terrain trend surface inclination angle into regions, and selecting a terrain trend surface inclination angle α for each region. x ; According to the concave and convex landforms of the mountain surface, the mountain surface characteristic coefficient D of each area is determined. x ; Divide the mining areas of the relative positions of multiple coal seams, compare the coal seam spacing with the "three zones" height, and obtain the correction of the subsidence coefficient parameters.

[0064] Preferably, the correction of the subsidence coefficient includes: classifying the repeated mining of multiple coal seams according to the position of the original upper coal seam after the mining of the lower coal seam, and adjusting the subsidence coefficient parameters according to the repeated mining of the overburden rock properties.

[0065] Preferably, the calculation of the distance between the upper coal seam and the lower coal seam includes: classifying the upper coal seam according to its location, and adjusting the sinking parameters under different circumstances accordingly; calculating the height of the collapse zone and the fault zone after the lower coal seam is mined according to the empirical formula in the specification, and determining the original position of the upper coal seam by comparing the relationship between the distance between the upper coal seam and the lower coal seam and the height of the collapse zone and the height of the fault zone.

[0066] like Figure 2-4 As shown in the figure, after longwall mining of the lower coal seam, the upper layer of the overburden surface forms a collapse zone, a fault zone, and a bending zone. Due to the different distances between the upper and lower coal seams, the original upper coal seam may be located in any of the three zones. According to the relative position of the original upper coal seam and the "three zones", it is divided into the following three situations:

[0067] (1) The original upper coal seam is located in the collapse zone after the lower coal seam is mined

[0068] In this case, the distance between the upper and lower coal seams is small, and the broken rock mass produced by mining the upper coal seam will collapse again along with the lower rock mass. Due to the existence of the upper broken rock mass, the direct top position may even move upward during repeated mining, and the collapse zone will increase accordingly. At this time, the impact on the movement of the overlying rock layer and the surface subsidence is superimposed, and the degree and scope of the impact are large.

[0069] (2) The original upper coal seam is located in the fault zone after the lower coal seam is mined

[0070] In this case, the distance between the upper and lower coal seams is larger than that in the previous case. Since the mining of the upper coal seam will only disturb the rock layer above it, the collapse zone formed by the excavation of the lower coal seam is less affected, and the superposition of the impact on the movement of the overlying rock layer and the surface subsidence is relatively small. However, part of the broken rock mass produced by the original upper coal seam mining is located in the fault zone of repeated mining. The broken rock mass is easier to break than the intact rock mass, and it will still have a certain superposition effect on the movement of the overlying rock layer and the surface subsidence.

[0071] (3) The original upper coal seam is located in the curved zone after the lower coal seam is mined

[0072] In this case, the distance between the upper and lower coal seams is large, the hollows in the curved zone produced by longwall coal seam mining are small, and the curved zone is almost only deformed by bending. The broken rock layer produced by the upper coal seam mining is also deformed by bending at the same time. If the upper coal seam is stopped for a long time at this time, the broken rock mass is relatively dense, and the bending deformation has little effect on the re-disturbance of the broken rock mass. At this time, repeated mining will not have a significant superimposed effect on the movement of the overlying rock layer and surface subsidence.

[0073] Preferably, the upper coal seam can be classified according to the three zones where it is located, and the parameters in different situations are adjusted accordingly. k , H li The calculation can adopt the empirical formula mentioned in the "Specifications for Coal Pillar Retention and Compressed Coal Mining in Buildings, Water Bodies, Railways and Main Shafts and Tunnels" (referred to as the "Three-Down Regulations").

[0074] According to the empirical formula in the specification, the height of the collapse zone and the fracture zone after the lower coal seam is mined can be calculated. By comparing the interburden between the upper and lower coal layers and the collapse zone height H k and the fracture zone height H li The size relationship can determine the location of the original upper coal seam. At the same time, the "Technical Specifications for Design and Construction of Goaf Highways" points out that under repeated mining conditions, the subsidence coefficient can be adjusted according to the nature of the overburden and the number of re-mining times (Table 2). In summary, the subsidence coefficient can be corrected as follows according to the location of the upper coal seam:

[0075] (1)IB<H k That is, the original upper coal seam is located in the collapse zone after the lower coal seam is mined. When calculating the mining of multiple coal seams, the subsidence coefficient is taken according to the soft overburden, and the parameters of the subsidence coefficient are adjusted according to the repeated mining situation.

[0076] (2)H k <IB<H k +H li That is, the original upper coal seam is located in the fault zone after the lower coal seam is mined. When calculating, the subsidence coefficient is taken according to the actual situation of the overlying rock, and the parameters of the subsidence coefficient are adjusted according to the repeated mining situation.

[0077] (3)IB>H k +H li That is, the original upper coal seam is located in the curved zone after the lower coal seam is mined. When calculating, the subsidence coefficient is determined according to the actual situation of the overlying rock, and no other adjustments are made to the parameters.

[0078] Table 2 Activation coefficient of repeated mining subsidence according to the nature of the overburden rock

[0079] Lithology One re-collection Secondary re-mining hard 0.15 0.20 medium hard 0.20 0.10

[0080] From the formula derived by the probability integral method, it can be seen that the main influencing angle tangent value and burial depth determine the value of the influencing radius r. When the overburden is relatively soft, it is more likely to deform after being disturbed, making the deformation more concentrated; while the overburden is relatively hard, and under the condition of the presence of cavities below, the upper layer is less likely to deform than when it is weak, which increases the deformation range. Based on the fact that the overburden lithology determines the influencing angle, the disturbed and undisturbed parts of the overburden strata are distinguished before the lower coal seam is mined, and different main influencing angle tangent parameters are selected for calculation. Because the main influencing angle tangent values ​​of different strata lithology are different, the situation is more complicated and difficult to obtain.

[0081] like Figure 1 , Figure 5 As shown in the figure, there are four types of stratum lithology, and the main influence angles of different stratum lithology are different. Before mining the lower coal seam, the overburden strata are divided into two states. Lithology 3 and lithology 4 are the parts where the strata have moved after mining the upper coal seam, and lithology 1 and lithology 2 are the parts that are not affected by mining the upper coal seam. Lithology 3 and lithology 4 can be regarded as weak overburden to set the parameters, while lithology 1 and lithology 2 are set according to the actual overburden conditions. The calculation formula of the influence radius r is adjusted to:

[0082] The influence angle of lithology 1 is β1, the height of lithology 1 is h1, and the main influence angle tangent is tanβ1. The influence angle of lithology 2 is β2, the height of lithology 2 is h2, and the main influence angle tangent is tanβ2. The influence angle of lithology 3 is β3, the height of lithology 3 is h3, and the main influence angle tangent is tannβ2. The influence angle of lithology 4 is β4, the height of lithology 4 is h4, and the main influence angle tangent is tanβ4. After lithology 3 is regarded as a weak overburden, the main influence angle tangent is tannβ′3, and after lithology 4 is regarded as a weak overburden, the main influence angle tangent is tanβ′4. The correlation table of different overburden lithologies and prediction parameters is shown in Table 1. The main influence angle is the angle of the mining coal seam influence range, which is the angle between the straight line of the main influence range boundary and the mining boundary and the horizontal line.

[0083] Table 1

[0084]

[0085] Data source: Specifications for the establishment of coal pillars and compressed coal mining in buildings, water bodies, railways and main shafts and tunnels

[74]

[0086] like Figure 6 As shown in the figure, the main influencing angle is corrected: lithology 3 and lithology 4 have been disturbed during the mining of the upper coal seam, and the main influencing angles of lithology 3 and lithology 4 are taken according to the weak overburden, that is, β′3 and β′4. Lithology 1 and lithology 2 are not disturbed and are still taken according to the actual values.

[0087] Preferably, the classification standards under overlapping forms include: dividing according to whether repeated mining areas occur and the positions of repeated mining areas according to the different positions of the upper coal seam and the lower coal seam; classifying the repeated mining of multiple coal seams by judging whether the relative positions of the upper coal seam and the lower coal seam produce repeated mining areas or the differences in the positions of the repeated mining areas, and adjusting the subsidence coefficient and main influencing angle parameters to determine whether repeated mining produces repeated mining areas.

[0088] The specific areas where repeated mining occurs are as follows: 1. Areas where repeated mining does not occur: for the different impact areas of the upper coal seam and the lower coal seam, the impact area of ​​the upper coal seam and the different impact areas of the lower coal seam are calculated according to the long-term deformation calculation model of the single coal seam goaf in the mountainous area; 2. Areas where repeated mining occurs (the locations of the repeated mining areas are classified, and the calculation steps are the same): areas where repeated mining occurs, there are still some non-repeated mining areas on the surface; ① Non-repeated mining areas: whether it belongs to the upper coal seam or the lower coal seam, the impact is calculated according to the long-term deformation calculation model of the single coal seam goaf in the mountainous area; ② Repeated mining areas: The moving deformation value of the upper coal seam and the moving deformation value of the lower coal seam need to be superimposed on the moving deformation calculation, and the subsidence coefficient and the tangent value of the main influencing angle of the lower coal seam need to be corrected.

[0089] Preferably, the calculation parameter adjustment method is: according to the different positions of the upper coal seam and the lower coal seam, the adjustment parameters are selected according to whether the repeated mining area occurs, and the long-term deformation prediction calculation method of the single coal seam goaf area of ​​different strata and lithology on the surface of the mountainous area of ​​each upper coal seam and lower coal seam is determined: the repeated mining area affected by the upper coal seam, the repeated mining area affected by the lower coal seam, and the repeated mining area affected by the upper coal seam and the lower coal seam;

[0090] For areas that have not been repeatedly mined, they are calculated according to whether they belong to the upper coal seam or the lower coal seam affected area; according to the long-term deformation prediction method of single coal seam goaf areas with different strata and lithology on the surface of mountainous areas;

[0091] For areas where repeated mining occurs, the upper coal seam is calculated using the long-term deformation prediction method for goafs of single coal seams with different strata and lithologies on the surface of mountainous areas. The lower coal seam is also calculated using the long-term deformation prediction method for goafs of single coal seams with different strata and lithologies on the surface of mountainous areas. It is necessary to correct the subsidence coefficient and the tangent value of the main influencing angle of the lower coal seam, and then superimpose the calculation results of the upper and lower coal seams to obtain the result of the repeated mining area.

[0092] Long-term deformation prediction of goaf areas in multiple coal seams with different strata and lithologies on the surface of mountainous areas. Because the repeated mining areas affected by the mining of lower and upper coal seams are different according to the positions of the upper and lower coal seams, it is necessary to analyze the situation and discuss. The following are various situations of different upper and lower coal seam positions in the mining of multiple coal seams with different strata and lithologies on the surface of mountainous areas (assuming that the repeated mining area is in the fc section, that is, on a positive slope, the repeated mining area is located in other areas and can be used as a reference).

[0093] In the following calculations, the lower coal seam cut is the starting point of the x-axis, and the distance between the upper coal seam cut and the lower coal seam cut is d. The height of lithology 1 is h1, and the main influencing angle tangent is tanβ1. The height of lithology 2 is h2, and the main influencing angle tangent is tanβ2. The height of lithology 3 is h3, and the main influencing angle tangent is tanβ3. The vertical distance between the ground surface and the interface between lithology 3 and 4 is h4, and the main influencing angle tangent of lithology 4 is tanβ4. The horizontal distance between points o and f is p1, the horizontal distance between points f and c is p2, and the horizontal distance between points c and g is p3. The inclination angle of the terrain trend surface of the jf section is -α1, the inclination angle of the terrain trend surface of the fc section is α2, the inclination angle of the terrain trend surface of the cg section is -α3, and the surface characteristic coefficient of the mountainous area of ​​the jt1 section is D x0 , the surface characteristic coefficient of the mountainous area in the t1ft2 section is D x1 , the surface characteristic coefficient of the mountainous area in the t2et3 section is D x2 t 3g The surface characteristic coefficient of the mountainous area is D x3 .

[0094] The steps are as follows: 1. First determine the coordinate system, with the opening of the coal seam as the starting point of the x-axis; 2. Correct the inclination angle of the terrain trend surface on the mountain surface, divide the area into different terrain trend surface inclination angles, and determine a terrain trend surface inclination angle α for each area. x ; 3. Divide the concave and convex landforms, positive slopes and reverse slopes of the mountainous surface into regions, and determine the mountainous surface characteristic coefficient D of each region x ; 4. Determine the location area of ​​repeated mining; 5. Divide the multi-coal seam mining area. At the initial stage of calculation, it is necessary to compare the coal seam spacing with the three-zone height, and make parameter corrections to the lower coal seam subsidence coefficient and the tangent value of the main influencing angle; 6. Determine the calculation formula for each section.

[0095] Case 1: If Figure 7 , mining of multiple coal seams with different lithologies on the surface of mountainous areas does not result in repeated mining areas, and there are areas that have not been deformed. For different areas, calculations can be performed on mining of single coal with different lithologies on the surface of mountainous areas. The ofa segment is the area affected by the lower coal seam, and the lower coal seam is calculated according to the long-term deformation of the goaf of a single coal seam with different strata lithologies on the surface of the mountainous area; the ab segment is where no movement and deformation occurs; the bc segment is the area affected by the upper coal seam, and the upper coal seam is calculated according to the long-term deformation of the goaf of a single coal seam with different strata lithologies on the surface of the mountainous area. The calculation steps are as follows:

[0096] 1. First determine the coordinate system, with the coal seam cut as the starting point of the x-axis.

[0097] 2. Correct the inclination angle of the terrain trend surface on the mountainous surface, divide the area into different terrain trend surface inclination angles, and determine a terrain trend surface inclination angle α for each area. x .

[0098] After measurement, the terrain trend surface inclination angle of the mountainous area is divided into three sections: the terrain trend surface inclination angle of the jf section is -α1, the terrain trend surface inclination angle of the fc section is α2, and the terrain trend surface inclination angle of the cg section is -α3.

[0099] 3. Divide the concave and convex landforms, positive slopes and reverse slopes of the mountainous surface into regions and determine the mountainous surface characteristic coefficient D of each region x jf is the reverse slope, fc is the positive slope, cg is the reverse slope, and the surface characteristic coefficient of the mountainous area in jt1 is D x0 , the surface characteristic coefficient of the mountainous area in the t1ft2 section is D x1 , the surface characteristic coefficient of the mountainous area in the t2et3 section is D x2 , t 2g The surface characteristic coefficient of the mountainous area is D x3 .

[0100] 4. Calculate the horizontal coordinates of points a, b, and c, that is, determine the repeated mining location area.

[0101] 5. Correction of the subsidence coefficient of the lower coal seam and the tangent value of the main influencing angle; No correction of the subsidence coefficient; Correction of the tangent value of the main influencing angle: There is no repeated mining area, and it is single coal seam mining. Calculate the main influencing coefficients of the upper and lower coal seams.

[0102] Main influencing coefficients of lower coal seam

[0103] Main influencing coefficients of upper coal seam

[0104] 6. Calculation formula for each segment: ofa segment (0≤x≤a point horizontal coordinate) (regarded as single coal seam mining in the lower coal seam):

[0105]

[0106] m1 is the thickness of the lower coal seam, q1 is the sinking coefficient, l 01 is the length of the hollow area on the left side of the lower coal seam, l′ 01 is the length of the hollow area on the right side of the lower coal seam. l1 is the length of the accumulation area in the middle of the goaf of the lower coal seam, n 01 is the number of blocks in the left cavity of the lower coal seam, n′ 01 It is used to divide the number of blocks in the cavity on the right side of the lower coal seam.

[0107] For different sections of terrain trend surface inclination angle a x , substituted segment by segment, that is, the terrain trend surface inclination angle of segment of is -α1, the terrain trend surface inclination angle of segment of fa is α2, and the surface characteristic coefficient D of different segments x , segment by segment, ot1 mountain surface characteristic coefficient D x0 , oa section mountain surface characteristic coefficient D x1 . ab section (a point horizontal coordinate ≤ x ≤ b point horizontal coordinate): not affected by any coal seam, no movement and deformation occurs. bc section (b point horizontal coordinate ≤ x ≤ c point horizontal coordinate), regarded as single coal seam mining in the upper coal seam:

[0108]

[0109] m2 is the thickness of the upper coal seam, q2 is the sinking coefficient, l 02 is the length of the cavity area on the left side of the upper coal seam, l′ 02 is the length of the hollow area on the right side of the upper coal seam. l′1 is the length of the accumulation area in the middle of the goaf of the upper coal seam, n 02 is the number of hollow blocks on the left side of the upper coal seam, n′ 02 It is used to divide the number of blocks in the cavity on the right side of the upper coal seam.

[0110] For different sections of terrain trend surface inclination angle α x , substituted segment by segment, that is, the inclination angle of the terrain trend surface of segment bc is α2, and the surface characteristic coefficient D of different segments x , segment by segment, bt2 mountain surface characteristic coefficient D x1 , t 2c The surface characteristic coefficient of the mountainous area is D x2 .

[0111] Case 2: The lower and upper coal seams are located in the area where repeated mining does not occur, that is, points a and b coincide with each other. It is necessary to recalculate the horizontal coordinates of points a and b. The calculation formula is the same as Figure 7 same.

[0112] Case 3: If Figure 8 The locations of the lower coal seam and the upper coal seam are areas where repeated mining occurs; and the intersection of the influence range of the lower coal seam and the upper coal seam is located in lithology 4, which is the lithology layer closest to the surface.

[0113] The OFB section is the influence area of ​​the lower coal seam. The lower coal seam is calculated according to the long-term deformation of the goaf of a single coal seam with different strata and lithology on the surface of the mountainous area. The BA section is the repeated mining area. The upper coal seam is calculated according to the long-term deformation of the goaf of a single coal seam with different strata and lithology on the surface of the mountainous area. The lower coal seam corrects the main influence angle and sinking coefficient, and then substitutes them into the long-term deformation calculation of the goaf of a single coal seam with different strata and lithology on the surface of the mountainous area. Finally, the results of the upper and lower coal seams are superimposed, and the result is the movement deformation of the repeated mining area. The AC section is the influence area of ​​the upper coal seam. The upper coal seam is calculated according to the long-term deformation of the goaf of a single coal seam with different strata and lithology on the surface of the mountainous area.

[0114] 1. First determine the coordinate system, with the coal seam cut as the starting point of the x-axis.

[0115] 2. Correct the inclination angle of the terrain trend surface on the mountainous surface, divide the area into different terrain trend surface inclination angles, and determine a terrain trend surface inclination angle α for each area. x .

[0116] After measurement and division of the terrain trend surface inclination of the mountainous surface, the terrain is divided into three sections, namely: the terrain trend surface inclination of the jf section is -α1, the terrain trend surface inclination of the fc section is α2, and the terrain trend surface inclination of the cg section is -α2.

[0117] 3. Divide the concave and convex landforms, positive slopes and reverse slopes of the mountainous surface into regions and determine the mountainous surface characteristic coefficient D of each region x jf is the reverse slope, fc is the positive slope, cg is the reverse slope, and the surface characteristic coefficient of the mountainous area in jt1 is D x0 , the surface characteristic coefficient of the mountainous area in the t1ft2 section is D x1 , the surface characteristic coefficient of the mountainous area in the t2et3 section is D x2 , the surface characteristic coefficient of the mountainous area in section t3g is D x3 .

[0118] 4. Calculate the horizontal coordinates of points a, b, c and h z (The height of point z from the bottom of lithology 4 formation).

[0119] 5. Correction of the lower coal seam subsidence coefficient and the tangent value of the main influencing angle.

[0120] Correction of subsidence coefficient: The distance between the upper and lower coal seams is compared with the height of the "three zones" to correct the subsidence coefficient. The corrected subsidence coefficient is q'. Correction of the tangent value of the main influencing angle: The tangent value of the main influencing angle and the burial depth determine the value of the influencing radius r.

[0121] Now, the disturbed and undisturbed parts of the overlying strata before the lower coal seam is mined can be distinguished, and different main influencing angle tangent parameters can be selected for calculation.

[0122]

[0123] Main influencing coefficients of lower coal seam

[0124] Main influencing coefficients of upper coal seam

[0125] 6. Calculation formula for each segment:

[0126] ob segment (the horizontal coordinate of point o ≤ x ≤ the horizontal coordinate of point b) (regarded as the mining of a single coal seam in the lower coal seam):

[0127]

[0128] The thickness of the lower coal seam is m1, and the subsidence coefficient is q1, l 01 is the length of the hollow area on the left side of the lower coal seam, l′ 01 is the length of the hollow area on the right side of the lower coal seam. l1 is the length of the accumulation area in the middle of the goaf of the lower coal seam, n 01 is the number of blocks in the left cavity of the lower coal seam, n′ 01 It is used to divide the number of blocks in the cavity on the right side of the lower coal seam.

[0129] For different sections of terrain trend surface inclination angle α x , the terrain trend surface inclination angle of the of segment is -α1, the terrain trend surface inclination angle of the fb segment is α2, and the surface characteristic coefficient D of different segments is x , segment by segment, ot1 mountain surface characteristic coefficient D xα , t1fb section mountain surface characteristic coefficient D x1 .

[0130] Section ba (the horizontal coordinate of point b ≤ x ≤ the horizontal coordinate of point a) (repeated mining area):

[0131]

[0132] The thickness of the lower coal seam is m1, and the subsidence coefficient is q1, l 01 is the length of the hollow area on the left side of the lower coal seam, l′ 01 is the length of the hollow area on the right side of the lower coal seam. l1 is the length of the accumulation area in the middle of the goaf of the lower coal seam, n 01 is the number of blocks in the left cavity of the lower coal seam, n′ 01 is the number of blocks in the right cavity of the lower coal seam. The thickness of the upper coal seam is m2, and the subsidence coefficient is q2, l 02 is the length of the cavity area on the left side of the upper coal seam, l′ 02 is the length of the hollow area on the right side of the upper coal seam. l′1 is the length of the accumulation area in the middle of the goaf of the upper coal seam, n 02 is the number of hollow blocks on the left side of the upper coal seam, n′ 02 It is used to divide the number of blocks in the cavity on the right side of the upper coal seam.

[0133] The inclination angle of the terrain trend surface of section ba is α2, and the surface characteristic coefficient of the mountainous area of ​​section ba is D x1 .

[0134] ac segment (a point abscissa ≤ x ≤ c point abscissa) (regarded as single coal seam mining in the upper coal seam):

[0135]

[0136] m2 is the thickness of the upper coal seam, q2 is the sinking coefficient, l 02 is the length of the cavity area on the left side of the upper coal seam, l′ 02 is the length of the hollow area on the right side of the upper coal seam. l′1 is the length of the accumulation area in the middle of the goaf of the upper coal seam, n 02 is the number of hollow blocks on the left side of the upper coal seam, n′ 02 It is used to divide the number of blocks in the cavity on the right side of the upper coal seam.

[0137] For different sections of terrain trend surface inclination angle α x , substituted segment by segment, that is, the inclination angle of the terrain trend surface of segment ac is α2, and the surface characteristic coefficient D of different segments x , substituting into the surface characteristic coefficient D of the mountainous area in at2 segment x1 , the surface characteristic coefficient of the mountainous area in section t2c is D x2 .

[0138] Case 4: A repeated mining area appeared, and the intersection of the influence range of the lower coal seam and the upper coal seam was located in lithology 3.

[0139] Case 5: If Fig. 9 , a repeated mining area appears, the cutting eye of the lower coal seam is located on the left side of the upper coal seam, and the intersection of the influence range of the lower coal seam and the upper coal seam is located at the upper coal seam (the bottom of lithology 3). It is necessary to calculate the horizontal coordinate of point a and point z (the height of point z from the bottom of lithology 4 formation) and the influence radius r′ of the repeated mining area, and substitute this into the formula of situation three.

[0140] Case 6: There are repeated mining areas, and the areas affected by the upper coal seam are all repeated mining areas.

[0141] Case 7: Similar to case 6, can be combined.

[0142] Case 8: There is a repeated mining area, and the areas affected by the upper coal seam are all repeated mining areas. The upper coal seam cut is located at the left end of the lower coal seam cut. Because the coordinate system takes the lower coal seam cut as the origin, the coordinates are slightly changed when calculating the upper coal seam.

[0143] Case 9: If Fig.10, repeated mining areas appear, and the intersection of the influence range of the lower coal seam and the upper coal seam is located at the upper coal seam (the bottom of lithology 3). The cut of the upper coal seam is located at the left end of the cut of the lower coal seam. Because the coordinate system takes the cut of the lower coal seam as the origin, the coordinates are slightly changed when calculating the upper coal seam.

[0144] 1. First determine the coordinate system, with the coal seam cut as the starting point of the x-axis.

[0145] 2. Correct the inclination angle of the terrain trend surface on the mountainous surface, divide the area into different terrain trend surface inclination angles, and determine a mountainous surface terrain trend surface inclination angle α for each area. x .

[0146] After measurement and division of the terrain trend surface inclination of the mountainous surface, the terrain is divided into three sections: the jf section has a terrain trend surface inclination of -α1, the fc section has a terrain trend surface inclination of α2, and the cg section has a terrain trend surface inclination of -α3.

[0147] 3. Divide the concave and convex landforms, positive slopes and reverse slopes of the mountainous surface into regions and determine the mountainous surface characteristic coefficient D of each region x . / f is the reverse slope, fc is the positive slope, cg is the reverse slope, and the surface characteristic coefficient of the mountainous area in jt1 is D x0 , the surface characteristic coefficient of the mountainous area in the t1ft2 section is D x1 , the surface characteristic coefficient of the mountainous area in the t2et3 section is D x2 , the surface characteristic coefficient of the mountainous area in section t3g is D x3 .

[0148] 4. Calculate the horizontal coordinates of points kb and c, that is, determine the repeated mining location area and calculate h z .

[0149] 5. Correction of the subsidence coefficient of the lower coal seam and the tangent value of the main influencing angle,

[0150] Correction of subsidence coefficient: Compare the distance between the upper and lower coal seams with the height of the three zones to correct the subsidence coefficient. The corrected subsidence coefficient is q′.

[0151] Correction of the tangent value of the main influence angle: The tangent value of the main influence angle and the burial depth determine the value of the influence radius r. Now, the disturbed and undisturbed parts of the upper stratum overburden before the lower coal seam mining can be distinguished, and different main influence angle tangent parameters can be selected for calculation.

[0152]

[0153] Main influencing coefficients of lower coal seam

[0154] Main influencing coefficients of upper coal seam

[0155] 6. Calculation formula for each segment:

[0156] bk segment (b point abscissa ≤ x ≤ k point abscissa) (regarded as single coal seam mining in the upper coal seam):

[0157]

[0158] The thickness of the upper coal seam is m2, and the sinking coefficient is q2, l 02 is the length of the cavity area on the left side of the upper coal seam, l′ 02 is the length of the hollow area on the right side of the upper coal seam. l′1 is the length of the accumulation area in the middle of the goaf of the upper coal seam, n 02 is the number of hollow blocks on the left side of the upper coal seam, n′ 02 It is used to divide the number of blocks in the cavity on the right side of the upper coal seam.

[0159] The inclination angle of the terrain trend surface in the bk section is α2, and the surface characteristic coefficient of the mountainous area in the bk section is D x1 .

[0160] kc segment (k point abscissa ≤ x ≤ c point abscissa) (repeated mining area):

[0161]

[0162] The thickness of the lower coal seam is m1, and the subsidence coefficient is q1, l 01 is the length of the hollow area on the left side of the lower coal seam, l′ 01 is the length of the hollow area on the right side of the lower coal seam. l1 is the length of the accumulation area in the middle of the goaf of the lower coal seam, n 01 is the number of blocks in the left cavity of the lower coal seam, n′ 01 is the number of blocks in the right cavity of the lower coal seam. The thickness of the upper coal seam is m2, and the subsidence coefficient is q2, l 02 is the length of the cavity area on the left side of the upper coal seam, l′ 02 is the length of the hollow area on the right side of the upper coal seam. l′1 is the length of the accumulation area in the middle of the goaf of the upper coal seam, n 02 is the number of hollow blocks on the left side of the upper coal seam, n′ 02 It is used to divide the number of blocks in the cavity on the right side of the upper coal seam.

[0163] The inclination angle of the terrain trend surface in the kc section is α2, and the surface characteristic coefficient of the mountainous area in the kt2 section is D x1 , the surface characteristic coefficient of the mountainous area in section t2c is D x2 .

[0164] cg segment (the horizontal coordinate of point c ≤ x ≤ the horizontal coordinate of point g) (can be regarded as the mining of the lower coal seam):

[0165]

[0166] m1 is the thickness of the lower coal seam, q1 is the sinking coefficient, l01 is the length of the hollow area on the left side of the lower coal seam, l′ 01 is the length of the hollow area on the right side of the lower coal seam. l1 is the length of the accumulation area in the middle of the goaf of the lower coal seam, n 01 is the number of blocks in the left cavity of the lower coal seam, n′ 01 It is used to divide the number of blocks in the cavity on the right side of the lower coal seam.

[0167] For different sections of terrain trend surface inclination angle α x , the slope of the terrain trend surface of the ce segment is α2, the slope of the terrain trend surface of the eg segment is -α3, and the surface characteristic coefficient D of different segments is x , segment by segment, cet2 mountain surface characteristic coefficient D x2 , the surface characteristic coefficient of the mountainous area in section t2g is D x3 .

[0168] Case 10: There is a repeated mining area, and the intersection of the influence range of the lower coal seam and the upper coal seam is located in lithology 3. The cut of the upper coal seam is located at the left end of the cut of the lower coal seam. Because the coordinate system takes the cut of the lower coal seam as the origin, the coordinates are slightly changed when calculating the upper coal seam.

[0169] Case 11: There is a repeated mining area, and the intersection of the influence range of the lower coal seam and the upper coal seam is located in lithology 4, which is the lithology closest to the surface. The cut of the upper coal seam is located at the left end of the cut of the lower coal seam. Because the coordinate system takes the cut of the lower coal seam as the origin, the coordinates are slightly changed when calculating the upper coal seam.

[0170] Case 12: There is no repeated mining area. The upper coal seam cutting eye is located at the left end of the lower coal seam cutting eye. Because the coordinate system takes the lower coal seam cutting eye as the origin, the coordinates are slightly changed when calculating the upper coal seam.

[0171] Case 13: There is no repeated mining area and there is an undeformed area. The upper coal seam cut is located at the left end of the lower coal seam cut. Because the coordinate system takes the lower coal seam cut as the origin, the coordinates are slightly changed when calculating the upper coal seam.

[0172] In the description of the present invention, it is necessary to understand that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0173] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for predicting long-term deformation of multi-coal seam goaf areas on the surface of mountainous areas, characterized by: include: Based on the probability integral method of equivalent variable mining thickness and the Knothe time function that describes the relationship between surface subsidence and time, a method for predicting long-term deformation of single coal seam goaf in horizontal ground is established. By zoning the goaf area, the surface movement deformation value caused by mining on flat land is superimposed with the mountain sliding amount to predict the surface mining movement deformation value in mountainous area, the influence of mining sliding on mountainous area is calculated, and then the long-term deformation prediction method of the goaf area of ​​single coal seam on horizontal ground is used to obtain the long-term deformation prediction method of the goaf area of ​​single coal seam on horizontal ground; The lithology of the formation is divided into different lithology types, and the intersection of the inclination line and the surface is calculated in sections according to the main influence angles of different stratum lithology. According to the influence range of different calculated surface points, the long-term deformation of the single coal seam goaf area with different stratum lithology on the surface of the mountainous area is calculated; In the multi-coal seam goaf with different stratum lithology on the surface of mountainous areas, the subsidence coefficient of the multi-coal seam goaf and the superposition calculation of the tangent value of the main influencing angle of different stratum lithology selection are corrected, and the classification standard and calculation parameter adjustment method under different spacing and overlapping forms of upper and lower coal seams are proposed; A long-term deformation prediction model for multi-coal seam goaf areas in mountainous areas is established to predict the long-term deformation of multi-coal seam goaf areas in mountainous areas.

2. The method according to claim 1, characterized in that: The method for establishing a long-term deformation prediction method for a single coal seam goaf area on a horizontal surface comprises: obtaining a probability integral method model of an equivalent variable mining thickness according to a calculation formula of any point on the ground by the probability integral method of equivalent variable mining thickness and combining the symmetry of the goaf area.

3. The method according to claim 1, characterized in that: The method for obtaining a long-term deformation prediction method for a single coal seam goaf area on a mountainous terrain comprises: obtaining at least one geomorphic data on the surface of a target mountainous area based on the division results of different mountainous surface landforms; obtaining an initial residual deformation value of the surface of the target mountainous area using the residual deformation value and the target geomorphic data; constructing a long-term deformation prediction model for a single coal seam goaf area on a mountainous terrain of the target mountainous area based on the corrected initial residual deformation value and the initial mountainous surface residual deformation prediction model, so as to use the long-term deformation prediction model for a single coal seam goaf area on a mountainous terrain to perform a long-term deformation prediction of the goaf area on the surface of the target mountainous area.

4. The method according to claim 3, characterized in that: The long-term deformation prediction model for single coal seam goaf areas in mountainous terrain includes: at least one of a residual subsidence calculation formula, a concave landform residual horizontal movement calculation formula, and a convex landform residual horizontal movement calculation formula.

5. The method according to claim 1, characterized in that: The influence range of the different calculated surface points includes: determining the intersection of the inclined straight line and the surface through the main influence angles of different stratum lithologies.

6. The method according to claim 1, characterized in that: The correction of the subsidence coefficient includes: classifying the repeated mining of multiple coal seams according to the position of the original upper coal seam after the lower coal seam is mined, and adjusting the subsidence coefficient parameters according to the repeated mining of the overburden rock properties.

7. The method according to claim 1, characterized in that: The calculation of the distance between the upper coal seam and the lower coal seam includes: classifying the upper coal seam according to its location and adjusting the sinking parameters under different circumstances accordingly; calculating the height of the collapse zone and the fault zone after the mining of the lower coal seam according to the empirical formula in the specification, and determining the original location of the upper coal seam by comparing the relationship between the distance between the upper coal seam and the lower coal seam and the height of the collapse zone and the height of the fault zone.

8. The method according to claim 1, characterized in that: The classification standards under the overlapping form include: according to the different positions of the upper coal seam and the lower coal seam, by judging whether the relative positions of the upper coal seam and the lower coal seam produce repeated mining areas or the positions of repeated mining areas, the repeated mining situations of multiple coal seams are classified, and the repeated mining of repeated mining areas is judged to adjust the subsidence coefficient and the main influencing angle parameters.

9. The method according to claim 1, characterized in that: The calculation parameter adjustment method includes: selecting adjustment parameters according to the different positions of the upper coal seam and the lower coal seam and whether repeated mining occurs in the area classification, and determining the long-term deformation prediction calculation method of the single coal seam goaf area in the mountainous area of ​​each upper and lower coal seam: For the non-repeated mining area, it is calculated according to whether it belongs to the upper coal seam or the lower coal seam affected area; according to the long-term deformation prediction method of the single coal seam goaf area with different strata and lithology on the surface of mountainous areas; For areas where repeated mining occurs, the upper coal seam is calculated using the long-term deformation prediction method for goafs of single coal seams with different strata and lithologies on the surface of mountainous areas; the lower coal seam is calculated using the long-term deformation prediction method for goafs of single coal seams with different strata and lithologies on the surface of mountainous areas. It is necessary to correct the subsidence coefficient and the tangent value of the main influencing angle of the lower coal seam, and then superimpose the calculation results of the upper and lower coal seams to obtain the result of the repeated mining area.

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