Method for determining short-distance thick coal seam mining comprehensive mining ratio and cracking mining ratio
阅读说明：本技术 一种近距离厚煤层采动综合垮采比及裂采比确定方法 (Method for determining short-distance thick coal seam mining comprehensive mining ratio and cracking mining ratio ) 是由 李江华 吴作启 李宏杰 李文 黎灵 李健 于 2020-05-15 设计创作，主要内容包括：本发明提出一种近距离厚煤层采动综合垮采比及裂采比确定方法,涉及煤矿水害防治技术领域。本方法步骤如下：步骤一、岩层强度类型划分；步骤二、判断下组煤垮落带高度和煤层间距的关系；步骤三、根据条件确定：步骤31、若下组煤垮落带高度K<Sub>2</Sub>≥煤层间距h<Sub>1-2</Sub>,则进行如下步骤：步骤311、确定近距离厚煤层开采综合采厚M<Sub>z</Sub>；步骤312、确定综合垮落带及综合导水裂隙带高度；步骤313、确定综合垮采比及综合裂采比；步骤32、若下组煤垮落带高度K<Sub>2</Sub><煤层间距h<Sub>1-2</Sub>,则进行如下步骤：步骤321、确定综合导水裂隙带高度；步骤322、确定综合裂采比。本发明的有益效果：应用于近距离厚煤层开采,可以准确确定其综合垮采比和综合裂采比,以准确预计采动岩层破坏高度。(The invention provides a method for determining a close-range thick coal seam mining comprehensive mining ratio and a cracking mining ratio, and relates to the technical field of coal mine water damage prevention and control. The method comprises the following steps: step one, dividing rock stratum strength types; step two, judging the relation between the height of a coal caving zone of the lower group and the coal seam spacing; step three, determining according to conditions: step 31, if the height K of the coal caving zone of the next group 2 Not less than coal seam spacing h 1‑2 Then, the following steps are carried out: step 311, determining the comprehensive mining thickness M of the close-range thick coal seam mining z (ii) a Step 312, determining the heights of the comprehensive caving zone and the comprehensive water flowing fractured zone; 313, determining a comprehensive mining ratio and a comprehensive fracturing ratio; step 32, if the height K of the coal caving zone of the next group 2 <Coal seam spacing h 1‑2 Then, the following steps are carried out: step 321, determining the height of the comprehensive water flowing fractured zone; and 322, determining the comprehensive fracturing-mining ratio. The invention has the beneficial effects that: the method is applied to the short-distance thick coal seam mining, and can accurately determine the comprehensive mining ratio and the comprehensive fracturing ratio so as to accurately predict the damage height of the mining rock stratum.)
1. A method for determining a short-distance thick coal seam mining comprehensive mining ratio and a cracking mining ratio is characterized by comprising the following steps:
step one, dividing rock stratum strength types
Dividing rock stratums among the coal seam groups and overlying rock stratums of the coal seam groups into hard rock stratums, medium hard rock stratums or weak rock stratums according to strength types;
step two, judging the relation between the height of the coal caving zone of the lower group and the coal seam interval
Step 21, determining the height K of the coal caving zone of the lower group2
If the rock stratum between the coal seam groups is a hard rock stratum, K2Is 7M2+5；
If the rock stratum between the coal seam groups is a medium-hard rock stratum, K2Is 6M2+5；
If the rock stratum between the coal seam groups is a weak rock stratum, K2Is 5M2+5；
Wherein the content of the first and second substances,
M2the mining thickness of the next group of coal is determined;
step 22, comparing the height K of the coal caving zone of the lower group2And the distance h between the coal seam1-2The relationship of (1);
step three, determining according to conditions
Step 31, if the height K of the coal caving zone of the next group2Not less than coal seam spacing h1-2Then, the following steps are carried out:
step 311, determining the comprehensive mining thickness M of the close-range thick coal seam miningz
Wherein the content of the first and second substances,
M1the mining thickness of the upper group of coal is adopted;
step 312, determining the height of the comprehensive caving zone and the comprehensive water flowing fractured zone
If the overlying strata of the coal seam group is hard strata, the height K of the caving zone of the overlying strata1Is 7M1+ 5; the height of the caving zone of the coal roof from the lower group is 7Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal seam group is a medium-hard stratum, the height K of the coal caving zone of the overlying strata1Is 6M1+ 5; the height of the caving zone of the coal roof from the lower group is 6Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal seam group is soft strata, the height K of the coal caving zone of the overlying strata1Is 5M1+ 5; the height of the caving zone of the coal roof from the lower group is 5Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal bed set is hard strata, the height L of the upper coal water flowing fractured zone1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group is
If the overlying strata of the coal bed set is a medium-hard stratum, the height L of the water flowing fractured zone of the overlying coal is determined1Is composed of
If the overlying strata of the coal bed set is soft strata, the height L of the water flowing fractured zone of the overlying coal is determined1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group is
313, determining the comprehensive mining ratio and the comprehensive fracturing ratio
The comprehensive caving ratio is the height Kz of the comprehensive caving zone and the comprehensive thickness MzThe ratio of (A) to (B);
the comprehensive fracturing-mining ratio is the height L of the comprehensive water-flowing fractured zoneZAnd comprehensive thickness mining MzThe ratio of (A) to (B);
step 32, if the height K of the coal caving zone of the next group2<Coal seam spacing h1-2Then, the following steps are carried out:
step 321 of determining the height L of the comprehensive water flowing fractured zoneZ
If the overlying strata of the coal bed set is hard strata, the height L of the water-flowing fractured zone of the overlying coal is1Is composed ofHeight L of lower coal water-flowing fractured zone2Is composed ofThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hc1The distance from the top plate of the lower group of coal to the top point of the water-flowing fractured zone of the lower group of coal is Hc2(ii) a Get Hc1And Hc2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
If the overlying strata of the coal bed set is a medium hard stratum, the height L of the water flowing fractured zone of the overlying coal is1Is composed ofHeight L of lower coal water-flowing fractured zone2Is composed ofThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hc1The distance from the top plate of the lower group of coal to the top point of the water-flowing fractured zone of the lower group of coal is Hc2(ii) a Get Hc1And Hc2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
If the overlying strata of the coal bed set is soft strata, the height L of the water flowing fractured zone of the overlying coal is1Is composed ofLower coal water-flowing fractured zoneHeight L2Is composed ofThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hc1The distance from the top plate of the lower group of coal to the top point of the water-flowing fractured zone of the lower group of coal is Hc2(ii) a Get Hc1And Hc2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
Step 322, determining the comprehensive fracturing-mining ratio
The comprehensive fracturing-mining ratio is the height L of the comprehensive water-flowing fractured zoneZWith the thickness M of the next coal mining group2The ratio of (a) to (b).
2. The method for determining the comprehensive mining ratio and the splitting ratio for short-distance thick coal seam mining according to claim 1, wherein in the first step,
comprehensive compressive strength of rock > 40MPaDividing the corresponding rock stratum into hard rock strata according to the intensity type;
20MPacomprehensive compressive strength of rock is less than or equal to 40MPaDividing the corresponding rock stratum into medium-hard rock strata according to the intensity type;
comprehensive compression strength of rock < 20MPaThe corresponding rock formation is classified into weak rock formations by intensity type.
3. The method for determining the comprehensive mining ratio and the fracture ratio of the short-distance thick coal seam mining according to claim 1, wherein in the step one, the comprehensive compressive rock strength of rock stratums among the coal seam groups is determined in the following way,
suppose there is y between coalbed groups1To yiThe rock strength uniaxial compressive strength of each rock stratum is C1、C2、C3…CiEach rock layer has a thickness of T1、T2、T3…TiThen, the comprehensive compressive strength of rock of the rock stratum among the coal seam groups is calculated as follows:
in the first step, the comprehensive compressive strength of the rock of the overlying rock layer of the coal bed is determined in the following way,
suppose there is y 'from top group coal top plate upwards'1To yi'rock formations, each rock formation having a uniaxial compressive strength of C'1、C′2、C′3…C′iEach rock stratum is T'1、T′2、T′3…T′iThen, the comprehensive compressive strength of rock of the overlying strata of the coal formation is calculated as follows:
Technical Field
The invention relates to the technical field of coal mine water damage prevention, in particular to a method for determining a short-distance thick coal seam mining comprehensive mining ratio and a cracking mining ratio.
Background
The hydrogeological conditions of mines in China are complex, and the amount of stagnant coal below water is large. The development height of overburden rock fracture is the basic basis for mine water damage prevention and control and underground water resource protection, and particularly for western mining areas in China, water resource and ecological environment protection are particularly important due to lack of water resources. The development height of the overburden failure fracture is influenced by the intensity type of the overburden and the mining method. In recent years, as resources gradually shift to deep parts, the number of short-distance thick coal seam mining working faces increases, and a strong water guide channel formed by high-strength mining is communicated with an upper aquifer, so that water inrush accidents are easy to happen, even casualties are caused, and simultaneously, underground water resource loss and ecological environment damage are caused. Therefore, the method is extremely important for predicting the damage height of the mining rock stratum caused by the short-distance thick coal seam mining, and the direct indexes for embodying the height are the comprehensive mining ratio and the comprehensive fracturing ratio. At present, no effective determination method for the comprehensive mining ratio and the comprehensive fracturing ratio exists in the prior art.
Disclosure of Invention
The invention aims to provide a method for determining a comprehensive mining ratio and a fracturing ratio for short-distance thick coal seam mining, which can accurately determine the comprehensive mining ratio and the comprehensive fracturing ratio for short-distance thick coal seam mining.
The invention provides a method for determining a close-range thick coal seam mining comprehensive mining ratio and a cracking mining ratio, which comprises the following steps:
step one, dividing rock stratum strength types
Dividing rock stratums among the coal seam groups and overlying rock stratums of the coal seam groups into hard rock stratums, medium hard rock stratums or weak rock stratums according to strength types;
step two, judging the relation between the height of the coal caving zone of the lower group and the coal seam interval
Step 21, determining the height K of the coal caving zone of the lower group2
If the rock stratum between the coal seam groups is a hard rock stratum, K2Is 7M2+5；
If the rock stratum between the coal seam groups is a medium-hard rock stratum, K2Is 6M2+5；
If the rock stratum between the coal seam groups is a weak rock stratum, K2Is 5M2+5；
Wherein the content of the first and second substances,
M2the mining thickness of the next group of coal is determined;
step 22, comparing the height K of the coal caving zone of the lower group2And the distance h between the coal seam1-2The relationship of (1);
step three, determining according to conditions
Step 31, if the height K of the coal caving zone of the next group2Not less than coal seam spacing h1-2Then, the following steps are carried out:
step 311, determining the comprehensive mining thickness M of the close-range thick coal seam miningz
Wherein the content of the first and second substances,
M1the mining thickness of the upper group of coal is adopted;
step 312, determining the height of the comprehensive caving zone and the comprehensive water flowing fractured zone
If the overlying strata of the coal seam group is hard strata, the height K of the caving zone of the overlying strata1Is 7M1+ 5; the height of the caving zone of the coal roof from the lower group is 7Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal seam group is a medium-hard stratum, the height K of the coal caving zone of the overlying strata1Is 6M1+ 5; the height of the caving zone of the coal roof from the lower group is 6Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal seam group is soft strata, the height K of the coal caving zone of the overlying strata1Is 5M1+ 5; the height of the caving zone of the coal roof from the lower group is 5Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal bed set is hard strata, the height L of the upper coal water flowing fractured zone1Is composed of
If the overlying strata of the coal bed set is a medium-hard stratum, the height L of the water flowing fractured zone of the overlying coal is determined1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group is
If the overlying strata of the coal bed set is soft strata, the height L of the water flowing fractured zone of the overlying coal is determined1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group isThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hb1The distance from the lower group of coal top plate to the top point of the water-flowing fractured zone of the lower group of coal top plate is Hb2(ii) a Get Hb1And Hb2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
313, determining the comprehensive mining ratio and the comprehensive fracturing ratio
The comprehensive caving ratio is the height Kz of the comprehensive caving zone and the comprehensive thickness MzThe ratio of (A) to (B);
the comprehensive fracturing-mining ratio is the height L of the comprehensive water-flowing fractured zoneZAnd comprehensive thickness mining MzThe ratio of (A) to (B);
step 32, if the height K of the coal caving zone of the next group2<Coal seam spacing h1-2Then, the following steps are carried out:
step 321 of determining the height L of the comprehensive water flowing fractured zoneZ
If the overlying strata of the coal bed set is hard strata, the height L of the water-flowing fractured zone of the overlying coal is1Is composed of
If the overlying strata of the coal bed set is a medium hard stratum, the height L of the water flowing fractured zone of the overlying coal is1Is composed of
If the overlying strata of the coal bed set is soft strata, the height L of the water flowing fractured zone of the overlying coal is1Is composed ofHeight L of lower coal water-flowing fractured zone2Is composed of
Step 322, determining the comprehensive fracturing-mining ratio
The comprehensive fracturing-mining ratio is the height L of the comprehensive water-flowing fractured zoneZWith the thickness M of the next coal mining group2The ratio of (a) to (b).
Furthermore, in the first step,
comprehensive compressive strength of rock > 40MPaDividing the corresponding rock stratum into hard rock strata according to the intensity type;
20MPacomprehensive compressive strength of rock is less than or equal to 40MPaDividing the corresponding rock stratum into medium-hard rock strata according to the intensity type;
comprehensive compression strength of rock < 20MPaThe corresponding rock formation is classified into weak rock formations by intensity type.
Further, in the step one, the comprehensive compressive strength of rock strata among the coal seam groups is determined in the following way, and the fact that y exists among the coal seam groups is assumed1To yiThe rock strength uniaxial compressive strength of each rock stratum is C1、C2、C3…CiEach rock layer has a thickness of T1、T2、T3…TiThen, the comprehensive compressive strength of rock of the rock stratum among the coal seam groups is calculated as follows:
in the first step, the comprehensive compressive strength of the rock of the overlying rock layer of the coal bed is determined in the following way,
suppose that the top plate of the self-organizing coal has y upward1' to yi'rock formations, each rock formation having a uniaxial compressive strength of C'1、C′2、C′3…C′iEach rock stratum is T'1、T′2、T′3…T′iThen, the comprehensive compressive strength of rock of the overlying strata of the coal formation is calculated as follows:
compared with the prior art, the method for determining the comprehensive mining ratio and the cracking mining ratio of the short-distance thick coal seam mining has the following characteristics and advantages:
the method for determining the short-distance thick coal seam mining comprehensive caving ratio and the cracking ratio is simple to implement and high in calculation precision, is applied to short-distance thick coal seam mining, can accurately determine the comprehensive caving ratio and the comprehensive cracking ratio of the short-distance thick coal seam mining, accurately predicts the damage height of a mining rock stratum, realizes early prevention and control on mine water damage prevention and control and water resource protection, and has important theoretical significance and practical significance on efficient and safe production of short-distance thick coal seam mining coal mines in western mining areas of China.
The features and advantages of the present invention will become more apparent from the detailed description of the invention when taken in conjunction with the drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a flow chart of a method for determining a comprehensive mining ratio and a fracturing ratio in short-distance thick coal seam mining;
FIG. 2 is a schematic diagram of a division of strata between groups of coal seams and overburden strata of the coal seams;
FIG. 3 shows the height K of the coal caving zone of the lower group2Not less than coal seam spacing h1-2A schematic diagram of the height LZ of the comprehensive collapse zone and the comprehensive water flowing fracture zone is obtained;
FIG. 4 shows the height K of the coal caving zone of the lower group2<Coal seam spacing h1-2And (3) obtaining a schematic diagram of the height LZ of the time-integrated water flowing fractured zone.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, the method for determining a short-distance thick coal seam mining comprehensive mining ratio and a fracturing ratio of the present invention will be described in detail with reference to the accompanying drawings.
In the description of the present invention, it should be noted that the terms "upper", "lower", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
As shown in fig. 1 to 4, the present embodiment provides a method for determining a comprehensive mining ratio and a fracturing ratio in short-distance thick coal seam mining, which includes the following specific steps:
step one, dividing rock stratum strength types
Comprehensive compressive strength of rock > 40MPaDividing the corresponding rock stratum into hard rock strata according to the intensity type;
20MPacomprehensive compressive strength of rock is less than or equal to 40MPaDividing the corresponding rock stratum into medium-hard rock strata according to the intensity type;
comprehensive compression strength of rock < 20MPaDividing the corresponding rock stratum into weak rock strata according to the intensity type;
as shown in fig. 2, the compressive strength of rock in the rock formations between the coal seam groups is determined by:
suppose there is y between coalbed groups1To yiThe rock force uniaxial compressive strength of each rock stratum is respectively C according to the rock mechanics test result1、C2、C3…CiObtaining the thickness of each rock stratum as T according to the geological data of the drilling1、T2、T3…TiThen, the comprehensive compressive strength of rock of the rock stratum among the coal seam groups is calculated as follows:
as shown in fig. 2, the compressive strength of the rock of the overburden on the coal formation is determined by:
suppose that the top plate of the self-organizing coal has y upward1' to yi' rock formations, and the rock force uniaxial compressive strength of each rock formation is respectively C ' according to the rock mechanics test result '1、C′2、C′3…C′iObtaining the thickness of each rock stratum as T 'according to the geological data of the drilling'1、T′2、T′3…T′iThen, the comprehensive compressive strength of rock of the overlying strata of the coal formation is calculated as follows:
statistics for the strata between the coalbed groups and the overburden of the coalbed are shown in table 1.
TABLE 1 statistical tables of formation properties and rock strength
The comprehensive compressive strength of rocks of rock stratums among the coal seam groups is 52.30MPa, and the comprehensive compressive strength of rocks of overlying rock stratums of the coal seam groups is 57.83 MPa.
In this embodiment, the interbedded strata and the overburden strata are divided into hard strata according to the strength type.
Step two, judging the relation between the height of the coal caving zone of the lower group and the coal seam interval
Step 21, determining the height K of the coal caving zone of the lower group2
If the rock stratum between the coal seam groups is a hard rock stratum, K2Is 7M2+5；
If the rock stratum between the coal seam groups is a medium-hard rock stratum, K2Is 6M2+5；
If the rock stratum between the coal seam groups is a weak rock stratum, K2Is 5M2+5；
Wherein the content of the first and second substances,
M2the mining thickness of the next group of coal is determined;
step 22, comparing the height K of the coal caving zone of the lower group2And the distance h between the coal seam1-2The relationship (2) of (c).
Step three, determining according to conditions
As shown in fig. 3:
step 31, if the height K of the coal caving zone of the next group2Not less than coal seam spacing h1-2Then, the following steps are carried out:
step 311, determining the comprehensive mining thickness M of the close-range thick coal seam miningz
Wherein the content of the first and second substances,
M1the mining thickness of the upper group of coal is adopted;
in the case shown in FIG. 3, the interbedded strata and the overburden are divided into hard strata according to the intensity type, and the mining thickness M of the interbedded coal13.5M, the mining thickness M of the next coal group29.7M, comprehensive thickness of MzIt was 9.97 m.
Step 312, determining the height of the comprehensive caving zone and the comprehensive water flowing fractured zone
If the overlying strata of the coal seam group is hard strata, the height K of the caving zone of the overlying strata1Is 7M1+ 5; the height of the caving zone of the coal roof from the lower group is 7Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal seam group is a medium-hard stratum, the height K of the coal caving zone of the overlying strata1Is 6M1+ 5; the height of the caving zone of the coal roof from the lower group is 6Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
if the overlying strata of the coal seam group is soft strata, the height K of the coal caving zone of the overlying strata1Is 5M1+ 5; the height of the caving zone of the coal roof from the lower group is 5Mz+ 5; the distance from the top plate of the lower coal group to the top point of the caving zone of the upper coal group is Ha1The distance from the lower group coal top plate to the top point of the caving zone of the lower group coal top plate is Ha2(ii) a Get Ha1And Ha2The larger of the median value is the height Kz of the comprehensive caving zone;
in this example, in the case shown in FIG. 3, the total collapse zone height Kz is 93.50 m.
If the overlying strata of the coal bed set is hard strata, the height L of the upper coal water flowing fractured zone1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group isThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hb1The distance from the lower group of coal top plate to the top point of the water-flowing fractured zone of the lower group of coal top plate is Hb2(ii) a Get Hb1And Hb2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
If the overlying strata of the coal bed set is a medium-hard stratum, the height L of the water flowing fractured zone of the overlying coal is determined1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group isThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hb1The distance from the lower group of coal top plate to the top point of the water-flowing fractured zone of the lower group of coal top plate is Hb2(ii) a Get Hb1And Hb2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
If the overlying strata of the coal bed set is soft strata, the height L of the water flowing fractured zone of the overlying coal is determined1Is composed ofThe height of the water-flowing fractured zone of the coal roof from the lower group isThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hb1The distance from the lower group of coal top plate to the top point of the water-flowing fractured zone of the lower group of coal top plate is Hb2(ii) a Get Hb1And Hb2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
In the present embodiment, in the situation shown in fig. 3, the height L of the water flowing fractured zone is synthesizedZ159.50 m.
313, determining the comprehensive mining ratio and the comprehensive fracturing ratio
The comprehensive caving ratio is the height Kz of the comprehensive caving zone and the comprehensive thickness MzThe ratio of (A) to (B);
the comprehensive fracturing-mining ratio is the height L of the comprehensive water-flowing fractured zoneZAnd comprehensive thickness mining MzThe ratio of (A) to (B);
in the present example, in the case shown in fig. 3, the comprehensive mining ratio is 9.38, and the comprehensive fracturing ratio is 16.00.
As shown in fig. 4:
step 32, if the height K of the coal caving zone of the next group2<Coal seam spacing h1-2Then, the following steps are carried out:
step 321 of determining the height L of the comprehensive water flowing fractured zoneZ
If the overlying strata of the coal bed set is hard strata, the height L of the water-flowing fractured zone of the overlying coal is1Is composed ofHeight L of lower coal water-flowing fractured zone2Calculating the height L of the water flowing fractured zone of the lower coal group according to the fact that the overlying rock stratum of the coal bed group is the medium hard rock stratum2Is composed ofThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hc1The distance from the top plate of the lower group of coal to the top point of the water-flowing fractured zone of the lower group of coal is Hc2(ii) a Get Hc1And Hc2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
If the overlying strata of the coal bed set is a medium hard stratum, the height L of the water flowing fractured zone of the overlying coal is1Is composed ofHeight L of lower coal water-flowing fractured zone2Calculating the height L of the water flowing fractured zone of the lower coal group according to the fact that the overlying rock stratum of the coal bed group is a weak rock stratum2Is composed of
If the overlying strata of the coal bed set is soft strata, the height L of the water flowing fractured zone of the overlying coal is1Is composed ofHeight L of lower coal water-flowing fractured zone2The height L of the water flowing fractured zone of the lower group of coal is calculated according to the fact that the overlying strata of the coal bed set is soft strata2Is composed ofThe distance between the top plate of the lower group of coal and the top of the water flowing fractured zone of the upper group of coal is Hc1The distance from the top plate of the lower group of coal to the top point of the water-flowing fractured zone of the lower group of coal is Hc2(ii) a Get Hc1And Hc2The value with the larger median is the height L of the comprehensive water flowing fractured zoneZ；
In the case shown in FIG. 4, the interbedded strata and the overburden are divided into hard strata according to the intensity type, and the mining thickness M of the interbedded coal13.5M, the mining thickness M of the next coal group25.5m, the height L of the upper coal-forming water-flowing fractured zone1107.2m, the height L of the lower coal water-flowing fractured zone285.1m, and the height L of the comprehensive water-flowing fractured zoneZ173.7 m.
Step 322, determining the comprehensive fracturing-mining ratio
The comprehensive fracturing-mining ratio is the height L of the comprehensive water-flowing fractured zoneZWith the thickness M of the next coal mining group2The ratio of (a) to (b).
In the present example, in the case shown in fig. 4, the comprehensive fracturing ratio was 31.58.
Up to this point, the present embodiment has been described in detail with reference to the accompanying drawings. From the above description, those skilled in the art should clearly understand that the method for determining the comprehensive mining ratio and the splitting ratio of short-distance thick coal seam mining according to the embodiment. The method for determining the short-distance thick coal seam mining comprehensive caving ratio and the cracking ratio is simple to implement and high in calculation precision, is applied to short-distance thick coal seam mining, can accurately determine the comprehensive caving ratio and the comprehensive cracking ratio of the short-distance thick coal seam mining, accurately predicts the damage height of a mining rock stratum, realizes early prevention and control on mine water damage prevention and control and water resource protection, and has important theoretical significance and practical significance on efficient and safe production of short-distance thick coal seam mining coal mines in western mining areas of China.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.
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