CN110284924B - Fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure and supporting method - Google Patents
Fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure and supporting method Download PDFInfo
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- CN110284924B CN110284924B CN201910556606.6A CN201910556606A CN110284924B CN 110284924 B CN110284924 B CN 110284924B CN 201910556606 A CN201910556606 A CN 201910556606A CN 110284924 B CN110284924 B CN 110284924B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
- E21F15/005—Methods or devices for placing filling-up materials in underground workings characterised by the kind or composition of the backfilling material
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
Abstract
The invention provides a multi-layer filling body bearing structure and a supporting method for gob-side entry retaining of a fully mechanized caving face. The multi-layer filling body can reduce vertical stress of a roadway direct roof and stress concentration of the filling body, high stress is transferred to the coal side, the bearing environment of the filling body is optimized, and stability of the filling body is improved. The type I cementing body absorbs and transfers partial external load by means of the self deformation-yielding characteristic, vertical stress of a roadway direct roof and stress concentration of the filling body are reduced, the type II cementing body with higher strength can ensure that reliable support is provided for the direct roof, the type I cementing body and the filling body are combined to adapt to rotary sinking of the direct roof, and the stability of the filling body is enhanced.
Description
Technical Field
The invention belongs to the technical field of roadway support, and particularly relates to a gob-side entry retaining multi-layer filling body bearing structure of a fully mechanized caving face and a support method.
Background
The gob-side entry retaining is a return air entry retaining using a transport entry retaining of an upper section working face as a lower section working face, which reduces the tunneling amount of the entry retaining, relieves the tension of mining and replacement, reduces the retention of coal pillars, eliminates the stress concentration of the upper and lower areas of the coal pillars, realizes Y-shaped ventilation of the working face, and solves the problems of over-limit and accumulation of gas at corners on the working face.
In recent years, Chinese scholars have made a great deal of research on the aspects of the activity rule of the retained surrounding rocks, the in-lane supporting and protecting technology and the like, and a rich theoretical basis is laid for the stability of the retained walls and the control of the surrounding rocks. The filling wall is used as the core of the gob-side entry retaining, and the stable bearing characteristic is very important. Along with the working face extraction, key blocks formed by periodic top fracture of the basic top of the gob-side entry retaining are rotated and sunk towards the goaf side by taking the rotating base point as an axis, the sinking value of the side close to the wall body is far greater than that of the solid coal side, and in the process, the filled wall body is necessary to avoid breaking instability and generate a proper amount of deformation and yielding so as to adapt to direct top sinking. In order to achieve the purpose, the direct roof is filled with wood between the concrete wall and the direct roof to serve as a soft medium, and the high compression rate of the soft medium is used for adapting to the rotary sinking of the direct roof; the paste filling material illustrates the 'yield-resistance' mechanism of an 'upper soft and lower hard' unequal strength filling body under the condition of a hard direct roof. The reserved top coal is used as a soft medium to improve the stress environment of the filling wall. The attempts provide a new idea for further improving the stress environment of the filling body and improving the stability of the surrounding rock of the roadway. The high-water material is widely applied to gob-side entry retaining because of the advantages of quick setting, early strength, flexible and adjustable strength, simple and convenient construction and the like. However, the filler constructed by the high-water material is also poor in deformation-yielding capacity and poor in capability of cooperating with the direct roof to deform, so that the filler can be seriously cracked and even unstably at the initial stage of the action of the direct roof.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to overcome the problems that the filling body which is constructed by a high-water material in the prior art has weak deformation-yielding capacity and poor cooperative deformation capacity with a direct roof, so that the filling body can be seriously cracked or even unstably at the initial stage of the action of the direct roof. Therefore, the invention provides a gob-side entry retaining multi-layer filling body bearing structure of a fully mechanized caving face and a supporting method to solve the problems.
In order to achieve the above purpose, the invention provides the following technical scheme:
a multi-layer filling body bearing structure of a fully mechanized caving face gob-side entry retaining is located in a goaf and used for supporting a top plate in the goaf;
the multi-layer filling body bearing structure comprises a type I cementing body and a type II cementing body;
the type I cementing body is positioned above the type II cementing body, the top of the type I cementing body is abutted against the direct top above the roadway, and the bottom of the type II cementing body is positioned on a roadway bottom plate of the goaf;
the width of the type I cementing body is the same as that of the type II cementing body, and the height of the type II cementing body is greater than that of the type I cementing body;
the compression ratio of the type I cement is greater than that of the type II cement, and the rigidity of the type I cement is lower than that of the type II cement.
According to the fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure, preferably, the height of the type I cementing body is 20% -30% of the height of the type II cementing body, the type I cementing body is used for deforming and yielding, and the type II cementing body is used for bearing.
Preferably, the II-type cementing body is a high-water-content quick-setting material consisting of two types of slurry A and B, the slurry A mainly comprises sulphoaluminate cement clinker, the slurry B mainly comprises lime gypsum, and the ratio of the two types of slurry A to slurry B is 1:1.
according to the fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure, preferably, the type I cementing body is a high water expansion material, the slurry of the type I cementing body is prepared by adding an air entraining agent and polypropylene fibers into the slurry of the type II cementing body, and the total amount of the added air entraining agent and the polypropylene fibers is not more than 3 per thousand of the total amount of the slurry of the type I cementing body;
more preferably, the compression ratio of the type i cement is between 6% and 10%.
According to the fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure, preferably, the height of the type I cementing body is 0.5m, and the height of the type II cementing body is 2.5 m.
The supporting method of the fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure preferably includes the following steps:
s1, establishing a multi-layer filling body bearing structure mechanical model, and analyzing the stress characteristics of the multi-layer filling body to obtain the height of each cementing body of the multi-layer filling body;
s2, analyzing a bearing deformation mechanism of the multi-layer filling body, further obtaining the deformation characteristics of the multi-layer filling body under two working conditions, and carrying out filling by adopting a type I cementing body and a type II cementing body;
s3, performing experiments and analysis on the materials of the type I cementing body and the type II cementing body in the step S2 to respectively obtain a high water swelling material and a high water quick setting material;
s4, preparing high-water-speed setting material slurry of the II-type cementing body and grouting, and then preparing slurry of the I-type cementing body on the basis of the slurry of the II-type cementing body and grouting again;
and S5, monitoring the deformation of the surrounding rock of the roadway after the multi-layer position filling body is loaded in the step S4.
The supporting method of the gob-side entry retaining multi-layer filling body bearing structure of the fully mechanized caving face includes, in step S1, the following steps:
s101, establishing a mechanical model of the multi-layer position filling body bearing structure according to the theory of masonry beam fracture, and obtaining:
in the formula: p is the pressure exerted on the lower rock stratum by the rotation and sinking of the old top;
E1is the elastic modulus of the I-type cementing body;
E2the elastic modulus of a II-type cementing body;
E3direct roof equivalent elastic modulus;
E4modulus of elasticity of the bottom coal;
h1is the height of a type I cementing body;
h2is the height of a type II cementing body;
h3is the immediate roof height;
h4is the height of the bottom coal;
x0the distance between the breaking point of the key block and the coal side;
b is the width of the retained roadway;
a is the width of the filling body;
l is the critical block fracture length;
s102, according to the filling body structure mechanical model obtained in the step S101, h is calculated1And increasing the height from 0m to 3m, obtaining a stress characteristic curve of the filling body, and synthesizing the factors of the maximum compression amount of the filling body and the material cost to obtain the height of the type I cementing body and the height of the type II cementing body.
Preferably, the step S2 of the method for supporting a gob-side entry retaining multi-level filling body bearing structure includes the following steps:
s201, dividing a working surface to be filled into two working conditions, namely a working condition I: the filling body completely adopts a II-type cementing body; working conditions are as follows: adopting a multi-layer filling body, wherein the bottom of the filling body adopts a II-type cementing body with the height of 2.5m, and the top of the filling body adopts an I-type cementing body with the height of 0.5 m;
s202, loading and applying vertical stress to the filler models in the first working condition and the second working condition respectively, obtaining a deformation curve of the filler, obtaining a high compression rate of the type I cementing body and a high strength of the type II cementing body, combining the high compression rate and the high strength to adapt to the rotary sinking of the top plate, and enhancing the stability of the filler.
Preferably, the step S3 of the method for supporting a gob-side entry retaining multi-level filler bearing structure on a fully mechanized caving face specifically includes the following steps:
s301, respectively carrying out uniaxial compression tests on a PZGS sample prepared from the high-water swelling material slurry and a PTGS sample prepared from the high-water quick-setting material slurry;
s302, obtaining stress-strain curves of the two samples under uniaxial compression according to the test results of the two samples in the step S301;
and S303, combining the high water swelling material and the high water rapid hardening material to form a multi-layer filling body according to the stress-strain curve in the step S302.
Preferably, the step S4 of the method for supporting a gob-side entry retaining multi-level filler bearing structure on a fully mechanized caving face specifically includes the following steps:
s401, mixing the slurry A and the slurry B with water according to a water-material ratio of 1.5: 1, preparing a high-water-speed setting material, grouting to form a II-type cementing body, and stopping grouting when the grouting of the II-type cementing body reaches 2.5 m;
s402, adding an air entraining agent and polypropylene fibers on the basis of the high-water-speed setting material slurry to obtain high-water-expansion material slurry, grouting again to form a type I cementing body, and stopping grouting when the height of the type I cementing body reaches 0.5 m.
Compared with the closest prior art, the technical scheme provided by the invention has the following excellent effects:
the invention provides a fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure and a supporting method, and compared with the prior art, the fully mechanized caving face gob-side entry retaining multi-layer filling body bearing structure at least has the following technical effects:
1. the multi-layer filling body can reduce vertical stress of a roadway direct roof and stress concentration of the filling body per se, and transfer high stress to the coal side, so that the self-bearing environment is optimized, and the stability of the filling body is further improved;
2. the type I cementing body absorbs and transfers partial external load by means of the self deformation-yielding characteristic, so that the vertical stress of the roadway direct roof and the stress concentration of the filling body are reduced, the type II cementing body with higher strength can ensure that reliable support is provided for the direct roof, the type I cementing body and the filling body can be combined to better adapt to the rotary sinking of the direct roof, and the stability of the filling body is enhanced;
3. the cementing body in the multi-layer filling body has the advantages of quick setting, early strength, flexible and adjustable strength, simplicity and convenience in operation, suitability for smooth underground operation of workers, capability of reducing the energy release speed of rock masses, stress concentration prevention and reduction of rock burst hazard.
Drawings
Fig. 1 is a schematic structural diagram of a gob-side entry retaining multi-layer filling body in the embodiment of the present invention;
FIG. 2 is a schematic representation of the stress-strain curve of a sample under uniaxial compression in an embodiment of the present invention;
FIG. 3 is a diagram illustrating a mechanical model of a multi-level packing loading system according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating a stress characteristic curve of a multi-level filling object according to an embodiment of the present invention;
FIG. 5 is a schematic view of a top plate vertical stress distribution profile according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a stress variation characteristic curve of a filling body according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a delamination of a filler in an embodiment of the invention;
FIG. 8 is a schematic diagram of deformation and reduction of area of roadway surrounding rock in the embodiment of the invention.
In the figure: 1. a top plate; 2. old topping; 201. old top A; 202. old top B; 203. old top C; 3. directly ejecting; 4. a coal body; 5. a roadway; 6. a class i cement; 7. a class II cement; 8. a gob; 9. and a plurality of layers of filling bodies.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity 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. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The noun explains:
Mohr-Coulomb constitutive model: a non-linear model based on engineering common soil parameters does not contain all non-linear characteristics of soil, and the Moire-Coulomb constitutive model can be applied to calculation of actual bearing capacity and failure load of a foundation and other calculations taking soil destruction as a key factor.
The invention provides a multi-layer filling body bearing structure of a gob-side entry retaining of a fully mechanized caving face, wherein a multi-layer filling body of the gob-side entry retaining is positioned in a gob and used for supporting a top plate 1 in the gob, and a roadway 5 is a channel tunneled for underground mining; during underground mining, the tunnel is a tunnel tunneled for mining lifting, transportation, ventilation, drainage, power supply and the like, the section of the tunnel 5 is mostly arched, trapezoidal or rectangular, the surrounding rock is soft and is round, oval or horseshoe-shaped, the tunnel 5 can be divided into an upright tunnel, a horizontal tunnel and an inclined tunnel according to the relation between the major axis and the horizontal plane, and the coal body 4 is coal to be excavated along the tunneling direction of the tunnel; after coal is excavated, the coal is conveyed to the ground through a roadway, a top plate 1 is a rock stratum above a coal body, the top plate 1 comprises a direct top 3 and an old top 2, and the old top 2 comprises an old top A201, an old top B202 and an old top C203. Under normal conditions, a false roof is attached to a coal body, the false roof is a thin rock stratum which is easy to collapse along with the extraction of coal, the thickness of the rock stratum is generally 0.3-0.5 m, the false roof is mostly composed of shale, carbonaceous shale and the like, if the false roof is absent, the rock stratum above the coal body 4 is a direct roof 3, the rock stratum is often collapsed along with the withdrawal of a support, the thickness of the rock stratum is generally 1-2 m, the direct roof 3 is generally clamped between the coal body 4 and the basic roof, the rock stratum is mostly composed of mudstone, rock, siltstone and other rocks which are easy to collapse, the thick and hard rock stratum above the direct roof 3 is a basic roof, the basic roof is also called an old roof 2, the old roof is often hung above a goaf 8 for a period of time, and the rock can not collapse once after the rock reaches a certain area, and the rock is generally composed of sandstone, rock, limestone and other hard rocks. After the coal body 4 is mined, a goaf 8 is formed, the upper direct roof 3 is not supported by the coal body 4 and is easy to collapse to cause safety accidents, the collapse of the direct roof 3 can also cause the suspension of the old roof 2 to cause collapse, the goaf 8 refers to a cavity area left after the underground coal seam is mined, after mining, the rock stratum covered on the goaf loses support, the original balance condition is destroyed, the overlying rock stratum generates moving deformation until collapse is destroyed, and finally various buildings on the earth surface are deformed and destroyed, and the earth surface sinks and caves in a large area. Filling bodies 9 are sequentially required to be filled between the coal bodies 4 and the bottom plate of the roadway 5 to support the direct roof 3, so that a new balance is achieved between the coal bodies 4 and the direct roof 3, and the balance relation among the coal bodies 4, the direct roof 3 and the old roof 2 is stabilized.
The invention provides a multi-layer filling body bearing structure of a gob-side entry retaining of a fully mechanized caving face, wherein a multi-layer filling body 9 bearing structure comprises a type I cementing body 6 and a type II cementing body 7, the type I cementing body 6 is positioned above the type II cementing body 7, the top of the type I cementing body 6 is abutted against a direct roof 3 above a roadway 5, the bottom of the type II cementing body 7 is positioned on a bottom plate of the roadway 5 of a goaf, the type I cementing body 6 is a novel high-water expansion material with high compression rate and low rigidity, the coordinated deformability of the multi-layer filling body 9 and the direct roof 3 is enhanced, the type II cementing body 7 is a high-water-speed solidification material with low compression rate and high rigidity, the reliable support is provided for the multi-layer filling body 9 and the direct roof 3, the upper part of the multi-layer filling body 9 is in contact connection with the direct roof 3, the lower part of the multi-layer filling body 9 is in contact connection with the working face, the multi-layer filling body 9 is horizontally positioned between the roadway 5 and, the vertical direction is positioned between the direct roof 3 and the bottom plate of the roadway 5; the type I cementing body 6 absorbs and transfers partial external load by means of the self deformation-yielding characteristic, reduces the vertical stress of the roadway direct roof 3 and the self stress concentration of the filling body, and the type II cementing body 7 with higher strength can ensure that reliable support is provided for the direct roof, and the combination of the type I cementing body and the filling body can better adapt to the rotary sinking of the direct roof and enhance the stability of the filling body.
The height of the type II cementing body 7 is greater than that of the type I cementing body 6, the height of the type I cementing body 6 is 20% -30% of that of the type II cementing body 7 (such as 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%), the type I cementing body 6 deforms and yields, the lower part of the type II cementing body 7 bears, and the stability of the bearing structure of the multi-layer position filling body 9 is enhanced, if the thickness of the type I cementing body 6 is greater than that of the type II cementing body 7, only the type I cementing body 6 depends on the deformation capability of deformation-yielding to coordinate when the direct roof collapses, so that the direct roof is suitable for the rotary subsidence of the direct roof, the type II cementing body 7 cannot play a due supporting role, and the multi-layer position filling body loses the due role. Solid three-dimensional structures are selected for 7 sites of the II-type cementing body and 6 sites of the I-type cementing body, the specifications of the three-dimensional structures of the upper layer and the lower layer are kept consistent, the solid three-dimensional shapes can better play the roles of supporting and deforming-offering, and the specific shapes can be selected according to the actual conditions of a field roadway, such as: the cylinder is suitable for being used under the conditions that the space is small and the collapse place is not particularly serious, and the cuboid is generally suitable for large roadways, direct roof single blocks, and places with large areas, large surfaces, and the like, which are bent and easy to collapse.
As shown in fig. 1, a type i cementing body 6 is arranged on the upper part of the multi-layer position filling body 9, a novel high water swelling material (hereinafter abbreviated as PZGS) with high compression rate and low rigidity is used, the coordinated deformation capability of the multi-layer position filling body 9 and the direct roof 3 is enhanced through the deformation-yielding of the material, the material is adapted to the rotary sinking of the direct roof 3, the property of the novel high water swelling material has high compression rate, and when the direct roof 3 is in rotary sinking, the material bears the direct roof 3 according to the specific property and can dissolve most of vertically downward acting force to protect the cementing body at the bottom; the bottom of the multi-layer filling body 9 is a II-type cementing body 7, and a low-compression-rate and high-rigidity high-water-speed setting material (PTGS for short) is used, so that the multi-layer filling body 9 can provide reliable support for the direct roof 3. The multi-layer filling body 9 is divided into two layers from top to bottom according to the different properties of the two materials, namely a type I cementing body 66 consisting of a novel high water swelling material and a type II cementing body 7 consisting of a high water rapid hardening material. The height of the filling body is regulated according to the height of the roadway space, the II-type cementing body 7 has the advantages of quick setting, early strength, flexible and adjustable strength, simple and convenient construction and the like, when the II-type cementing body 7 is filled to reach the specified height, the prepared modifier is added into the slurry on the basis of the original material to prepare the PZGS material, and then the pumping is continued to finish the filling of the I-type cementing body 6.
The II-type cementing body 7 is a high-water-content quick-setting material with low compression rate and high rigidity, the high-water-content quick-setting material is composed of two slurries, the ratio of the slurry material to water is 1: 1.2-1: 1.8 (such as 1:1.2, 1:1.3, 1:1.4 and 1:1.5), the ratio of the slurry material to water is preferably 1:1.5 in the embodiment, the dual slurries can lose fluidity within 8-10 min and harden within 18-20 min after being mixed, and the 1d strength can reach 50% of the final strength; the type I cementing body 6 is a novel high-water-content expansion material with high compression rate and low rigidity, the compression rate of the type I cementing body 6 is 6-10 per mill (such as 6 per mill, 7 per mill, 8 per mill, 9 per mill and 10 per mill), the novel high-water-content expansion material is obtained by adding a proper amount of air entraining agent and polypropylene fiber on the basis of a high-water quick-setting material, and the addition amount of the air entraining agent and the polypropylene fiber does not exceed 3 per mill of the total amount of the type I cementing body 6. The high water content expanding material has the characteristics of quick setting and early strength, and also has relatively high compression ratio and residual strength.
The II-type cementing body is a high-water-content quick-setting material consisting of two types of slurry A and B, the slurry A mainly comprises sulphoaluminate cement clinker, the slurry B mainly comprises limestone gypsum, and the ratio of the two types of slurry A to slurry B is 1: compared with the traditional cement concrete, the high-water-content quick-setting material has the advantages that water replaces sand materials, has the function of 'forming stone by water dropping', is widely applied to the fields of coal metallurgy, building, environmental protection, water conservancy, traffic, petroleum and the like, and is a multifunctional engineering construction material. The material has high early strength and good cementing property, and is particularly suitable for serving as a roadway side support and cementing material.
In order to better understand the effect of the multi-level filling and the actual performance in a real coal mine, the invention also provides a supporting method of the gob-side entry retaining multi-level filling body bearing structure of the fully mechanized caving face, and the test method comprises the following steps:
and S1, establishing a mechanical model of the bearing structure of the multi-layer filling body, and analyzing the stress characteristics of the multi-layer filling body to obtain the height of each cementing body of the multi-layer filling body.
S101, establishing a mechanical model of the multi-layer position filling body bearing structure according to the theory of masonry beam fracture, and obtaining:
s102, according to the filling body structure mechanical model obtained in the step S101, h is calculated1And increasing the height from 0m to 3m, obtaining a stress characteristic curve of the filling body, and synthesizing the factors of the maximum compression amount of the filling body and the material cost to obtain the height of the type I cementing body and the height of the type II cementing body.
According to the theory of masonry beams, the fractured old roof 2 and the surrounding rock mass are mutually hinged to form a balance body similar to a masonry structure after the goaf contacts stable gangue, and a mechanical model of a bearing structure of a multi-level filling body 9 is established, as shown in fig. 3.
Assuming that the overburden is uniformly applied to the old crown 2, a given deformation S applied by the old crown B202 to the underlying overburden during the rotary subsidence can be expressed as:
in the formula: x is the number of0Is key toDistance between the block fracture point and the coal side;
b is the width of the retained roadway;
a is the width of the filling body;
l is the critical block fracture length;
and deltaS is the maximum sinking value of the key block at the mining area side.
The following can be obtained from equation (2):
ΔS＝m+h3(1-K) (2)
in the formula: k is the direct ejection residual crushing and swelling coefficient:
h3the height of the direct roof is m, and the mining height of the working face is m.
The critical block break length L is:
in the formula: l' is the working face periodic pressure step distance;
d is the length of the working surface.
4311 working plane x is known0＝6.9m，D＝210m，l′＝30m，K＝1.13，m＝6.3m，b＝3m，a＝2m，h3The maximum compression of the filler was found to be 433mm at 38.4 m.
The given deformation applied to the lower rock mass by the rotary subsidence of the old roof B202 is mainly shared by the direct roof 3, the multi-layer position filling 9 body and the bottom coal, so that the method comprises the following steps:
S＝S1+S2+S3+S4 (4)
in the formula: s1The deformation of the type I cementing body 6;
S2the deformation of the II-type cementing body 7;
S3is the deformation of the immediate roof;
S4the deformation amount of the bottom coal.
The amount of deformation of the above formation within the elastic range can be expressed as:
in the formula: p is the pressure exerted on the lower rock stratum by the rotation and sinking of the old jack 2;
E1is the elastic modulus of a category I cementing body 6;
E2the elastic modulus of the II-type cementing body 7;
E3direct roof equivalent elastic modulus;
E4modulus of elasticity of the bottom coal;
h1is 6 height of I type cementing body;
h2is the height of a type II cementing body 7;
h3is the immediate roof height;
h4is the height of the bottom coal.
Given a true height of 3m for the entry, the equation (5) is substituted into (4) to obtain:
the expressions (1) and (6) both represent the deformation of the lower rock body in the rotating and sinking process of the direct roof, the expressions are equal, and after the expressions are arranged, P is obtained as follows:
the 6 h height of the type I cement can be analyzed by the formula (7)1The rule of influence of the change on the stress of the filling body is taken as E1＝1.6GPa，E2＝2.17GPa，E42.6GPa, direct equivalent modulus of elasticity E33.2GPa at a height h of 6 class I cement1When the stress characteristic curve of the filling body is increased from 0 to 3m, the stress characteristic curve is shown in figure 6.
As shown in fig. 4, the force characteristic curve of the multi-layer bit packing 9 is: the stress of the multi-layer position filling body is in inverse proportion to the thickness of the type I cementing body 6, namely, the stress of the multi-layer position filling body 9 is gradually reduced along with the increase of the thickness of the type I cementing body 6. The type I cementing body 6 has stronger deformation-yielding capacity, can absorb and transfer part of external load, and is beneficial to the stability of the multi-layer filling body 9.
And S2, analyzing the bearing deformation mechanism of the multi-layer filling body, further obtaining the deformation characteristics of the multi-layer filling body under two working conditions, and carrying out filling by adopting the type I cementing body and the type II cementing body.
S201, dividing a working surface to be filled into two working conditions, namely a working condition I: the filling body completely adopts a II-type cementing body; working conditions are as follows: adopting a multi-layer filling body, wherein the bottom of the filling body adopts a II-type cementing body with the height of 2.5m, and the top of the filling body adopts an I-type cementing body with the height of 0.5 m;
s202, loading and applying vertical stress to the filler models in the first working condition and the second working condition respectively, obtaining a deformation curve of the filler, obtaining a high compression rate of the type I cementing body and a high strength of the type II cementing body, combining the high compression rate and the high strength to adapt to the rotary sinking of the top plate, and enhancing the stability of the filler.
At present, field test is carried out by taking the working surface of the Chengzhuang ore 4311 as a simulation object, and the supporting effect of the filling body at multiple layers is verified to be better than that of other filling bodies.
The 4311 working face is provided with 3 lanes, 43111 lane, 43112 lane and 43113 lane, the working face adopts a two-in one-return ventilation mode, namely, the 43111 lane and the 43113 lane are air inlet lanes, the 43112 lane is air return lanes, the section of the lane is 5 multiplied by 3.2m, the lane is supported by an anchor net cable, the working face is inclined by 210m in width, and the heading length is 1318.4 m. The stability of the structure of the mature ore 4311 coal mine is used as a simulation object, and favorable conditions are provided for the accuracy of test data and the convenience of test operation. The physical and mechanical parameters of the top and bottom plates of the working face are shown in the table 2. When modeling, the model size is 145 × 120 × 45m (length × width × height) according to the symmetry principle, and 85800 unit bodies are in total. The upper boundary of the model is applied with 11MPa vertical stress, the left and right boundaries are applied with displacement constraint in the horizontal direction, the bottom boundary is applied with displacement constraint in the vertical direction, and the lateral pressure coefficient is 0.5. The coal bed, the filling body and other rock stratums in the model adopt a Mohr-Coulomb constitutive model. The working face is excavated for 40 times along with 3m excavation each time. The size of the bearing structure of the multi-layer position filling body 9 is 6 multiplied by 2 multiplied by 3m (length multiplied by width multiplied by height), and the filling is carried out along with the excavation of the working face. In order to better reflect the bearing characteristics of the multi-layer filling body and the influence on the stress of the surrounding rock of the roadway, the simulation is carried out under two working conditions.
The working condition I is as follows: the filling body completely adopts a II-type cementing body 7;
working conditions are as follows: a multi-layer position filling body 9 is adopted, namely a type II cementing body 7 is adopted at the bottom of the filling body, the height is 2.5m, and a type I cementing body 6 is adopted at the top of the filling body, and the height is 0.5 m.
TABLE 24311 working face Top and bottom floor formation physico-mechanical parameters
(2) Analysis of simulation results
As shown in fig. 5, the top plate vertical stress distribution characteristic curve:
a) the goaf belongs to a pressure relief area, the load of an overlying strata is jointly borne by a coal body 4 and a filling body, and the vertical stress distribution of the direct roof 3 is in a double-peak shape.
b) "Multi-level" fill has the characteristic of transferring high stresses. The working condition I is as follows: the vertical stress peak value of the direct roof 3 above the filling body of the II type cementing body 7 is 12.1MPa and is positioned at a position 44.1m away from the left boundary of the model, while the vertical stress peak value above the coal body 4 is 23.8MPa, and the peak point is about 3.3m away from the coal wall. Working conditions are as follows: the vertical stress peak value of the direct roof 3 above the multi-layer filling body 9 is 9.5MPa, which is reduced by about 21.5% compared with the working condition, the stress peak value is positioned at a position 44.6m away from the left boundary of the model, the vertical stress peak value of the direct roof 3 at the coal body 4 side is 25.7MPa, which is increased by about 8.0% compared with the working condition, and the peak value point is positioned at a position 2.6m away from the coal wall.
c) The filling body with multiple layers can further reduce vertical stress of the direct roof 3 above the roadway, optimize stress distribution of surrounding rocks of the roadway, enable the roadway to be maintained in a low stress area, and facilitate the stability of the surrounding rocks of the roadway. The minimum value of the vertical stress above the roadway in the first working condition is 8.3MPa, and the minimum value of the vertical stress above the roadway in the second working condition is 7.3MPa, which is reduced by about 12.0 percent compared with the first working condition.
As shown in fig. 6, the characteristic curve of the change of the stress of the filling body is as follows: the variation trends of the load bearing characteristics of the filling body under the two working conditions are basically consistent. However, the vertical and horizontal stresses of the "multi-level" pack are significantly less than those of a pack consisting entirely of the type ii cement 7 (i.e., condition one), indicating that the "multi-level" pack 9 reduces its own stress concentration through stress transfer and "deformation-yielding". Taking the working face propulsion of 24.0m as an example, the working condition one is as follows: the vertical stress on the filling body is 21.2MPa, and the horizontal stress on the filling body is 4.7 MPa; working conditions are as follows: the vertical stress applied to the filling body is 17.6MPa, the horizontal stress is 3.2MPa, and the vertical stress and the horizontal stress are respectively reduced by about 17.0 percent and 31.9 percent compared with the working condition.
S3, the materials of the type i cement and the type ii cement in the step S2 are tested and analyzed as a high water swelling material and a high water rapid hardening material, respectively.
S301, respectively carrying out uniaxial compression tests on a PZGS sample prepared from the high-water swelling material slurry and a PTGS sample prepared from the high-water quick-setting material slurry;
s302, obtaining stress-strain curves of the two samples under uniaxial compression according to the test results of the two samples in the step S301;
and S303, combining the high water swelling material and the high water rapid hardening material to form a multi-layer filling body according to the stress-strain curve in the step S302.
A rigid servo testing machine with performance indexes and a testing system meeting requirements is selected to carry out pressure testing on the sample, and the RMT-301 type uniaxial rock mechanics testing machine is preferably selected to carry out pressure testing on the sample.
The high water quick-setting material sample is a cylindrical sample with d of 50mm and L of 100 mm.
The sample of the novel high water swelling material is a cylinder sample with d being 50mm and L being 100 mm.
According to the standard of the engineering rock mass test method: GB/T50266 and 2013 select a cylindrical sample with d being 50mm and L being 100 mm. The conclusion is drawn that the class II cement 7 has a higher stiffness and a lower compressibility than the class I cement 6.
The mechanical parameters of the two types of high-water materials measured by the mechanical testing machine in the step S1 by the test specimens in the step S2 and the step S3 are shown in table 1.
In the table RcPeak intensity; epsiloncIs the peak strain; c is cohesion;
is an internal friction angle; e is the modulus of elasticity; mu is Poisson's ratio.
TABLE 1 high Water Material mechanical parameters
The fracture morphology of the sample under uniaxial compression can be seen: PTGS dominated longitudinal cleave failure under uniaxial compression with localized spalling, the specimens exhibited relatively distinct brittle failure characteristics, exhibiting a typical tensile failure mode, PZGS dominated shear failure with tensile fracture, and the specimens were less brittle, exhibiting a tensile shear failure mode.
As shown in fig. 2, the stress-strain curve of the sample under uniaxial compression is given by: the stress-strain curves of PZGS and PTGS have a large difference. In the compaction stage (oa or o 'a'), the degree of curve concavity is obviously higher than that of a PTGS material due to more tiny pores in the PZGS; the elastic stage (ab or a 'b'), the average modulus of the PZGS is smaller than that of the PTGS, and after the PZGS bears the same load, larger pressure-yielding deformation is generated; after the yield stage (bc or b 'c') is started, the curve gradually becomes gentle, the slope is reduced, the microcracks in the sample gradually expand and penetrate, and the sample generates irreversible plastic deformation. Peak intensity of PZGS RcPeak strength R of the corresponding PTGS at 9.86MPac12.94MPa, but the former corresponds to a peak strain εc1＝6.72×10-3The peak strain ε of the latterc2＝4.8×10-3The peak strain of PZGS is improved by about 28.6 percent on the basis of PTGS; after entering the post-failure phase (cd or c'd'), the stress-drop rate of the PZGS is much lower than that of the PTGS, while the corresponding residual strength is higher than that of the PTGS, mainly because the polypropylene fibers act as one-dimensional lacing or net-type three-dimensional lacing inside the PZGSAnd the load sharing device can share part of external load. In addition, Table 1 also shows the Poisson ratio μ and internal friction angle of PZGS
Less than PTGS, and cohesive force c greater than PTGS.
The above analysis can show that the differences of the two materials in the aspects of resisting inelastic deformation, peak strain, post-peak stress drop rate, failure characteristics and the like indicate that the PTGS has more obvious brittleness characteristics than the PZGS. PTGS, although having higher strength, has poor compressibility, whereas PZGS, although having a lower strength than the former, has itself higher compressibility.
And S4, preparing high-water-speed setting material slurry of the II-type cementing body and grouting, and then preparing slurry of the I-type cementing body on the basis of the slurry of the II-type cementing body and grouting again.
S401, mixing the slurry A and the slurry B with water according to a water-material ratio of 1.5: 1, preparing a high-water-speed setting material, grouting to form a II-type cementing body, and stopping grouting when the grouting of the II-type cementing body reaches 2.5 m;
s402, adding an air entraining agent and polypropylene fibers on the basis of the high-water-speed setting material slurry to obtain high-water-expansion material slurry, grouting again to form a type I cementing body, and stopping grouting when the height of the type I cementing body reaches 0.5 m.
And S5, monitoring the deformation of the surrounding rock of the roadway after the multi-layer position filling body is loaded in the step S4.
Selecting two filling bodies with a certain distance, drilling vertical holes in the center of each filling body on the roadway side, installing a group of multipoint displacement meters (comprising three displacement base points) in each hole, wherein the burial depths of the base points are 0.5m, 1.0m and 1.5m in sequence, the two groups of displacement meters are named as SJD-1 and SJD-2 in sequence, monitoring to obtain the final separation amount and the separation percentage of the filling bodies after the roadway surrounding rock is deformed stably, and calculating results are shown in table 3. The delamination percentage is the percentage of the ratio of the delamination amount measured at different base points to the total delamination amount.
TABLE 3 transverse delamination Tab of the filling
In order to visually express the transverse delamination characteristics of the filling body, monitoring data of the SJD-1 multipoint displacement meter are extracted, and a curve of the delamination amount and the delamination percentage along with the change of the transverse depth of the filling body is drawn, as shown in FIG. 7. As can be seen, in the range of 0-0.5 m of the I area, the separation layer amount of the filling body reaches 178mm, which accounts for 86% of the total separation layer amount, and the breakage degree of the filling body is large; the separation layer amount of the zone II (0.5-1.0) m and the zone III (1.0-1.5) m is 17mm and 12mm respectively, the separation layer amounts to 8.2% and 5.8% of the total separation layer amount respectively, and the filling body keeps high integrity. Under mining influence, the distribution of the lateral delamination of the "multi-level" filling body shows obvious regionality, and the delamination amount is obviously reduced along with the increase of the lateral depth of the filling body. The multi-layer filling body absorbs and transfers part of given deformation and additional load generated by the rotary sinking of the key block by means of the deformation-load consumption characteristic of the multi-layer filling body, and effectively avoids the integral damage of the filling body caused by overlarge brittleness.
The deformation amount and the area shrinkage rate of the surrounding rock of the roadway drawn according to the measured data are shown in fig. 8, and it can be seen that the final approach amount of two sides of the roadway under the mining influence is 350-490 mm, the final approach amount of the top and bottom plates is 290-470 mm, the average shrinkage rate of the cross section of the roadway is 20-30%, and the requirement of mining on the working surface of the lower section can be met.
In summary, the following conclusions can be drawn:
(1) the PTGS mainly has longitudinal splitting fracture under uniaxial compression and presents a typical tensile fracture mode, and the modified PZGS mainly has shear fracture accompanied with tensile fracture and presents a tensile shear fracture mode; average modulus E of PZGS, Poisson's ratio mu, and internal friction angle
Compressive strength Rc and stress drop Rate less than PTGS, and corresponding Peak Strain εcCohesion c and residual strength are greater than PTGS, which has a more pronounced brittle failure characteristic than PZGS.
(2) The composite filling idea of constructing the multi-layer filling body is provided, a mechanical model of the bearing structure of the multi-layer filling body is established, the maximum compression amount of the multi-layer filling body is calculated, and the inverse relation between the stress of the multi-layer filling body 9 and the thickness of the I-type cementing body 6 is obtained.
(3) The type I cementing body 6 absorbs and transfers partial external load by means of the self deformation-load consumption characteristic, the vertical stress of a roadway roof and the self stress concentration of the filling body are reduced, the type II cementing body 7 with higher strength can ensure that reliable support is provided for the roof, the type I cementing body and the filling body can be combined to be well suitable for the rotary sinking of the roof, and the stability of the filling body is enhanced.
(4) The deformation of the 'multi-layer position' filling body 9 can be divided into three stages, wherein two rapid deformation periods are included and are respectively positioned in the ranges of 35-90 m and 110-140 m behind the working surface; practice shows that the multi-level filling body 9 can still keep high integrity after undergoing severe roof structure adjustment, the average shrinkage rate of the roadway section is 20-30%, and the requirement of lower section working face recovery can be met.
The above description is only exemplary of the invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the invention is intended to be covered by the appended claims.
Claims (5)
1. A supporting method of a multi-layer filling body bearing structure of a gob-side entry retaining of a fully mechanized caving face is characterized in that the multi-layer filling body bearing structure is located in a gob and used for supporting a top plate in the gob;
the multi-level filling body is horizontally positioned between the roadway and the gob, and vertically positioned between the direct roof and the roadway floor;
the multi-layer filling body bearing structure comprises a type I cementing body and a type II cementing body;
the type II cementing body and the type I cementing body both adopt solid three-dimensional structures;
the type I cementing body is positioned above the type II cementing body, the top of the type I cementing body is abutted against the direct top above the roadway, and the bottom of the type II cementing body is positioned on a roadway bottom plate of the goaf;
the width of the type I cementing body is the same as that of the type II cementing body, and the height of the type II cementing body is greater than that of the type I cementing body;
the compression ratio of the type I cementing body is greater than that of the type II cementing body, and the rigidity of the type I cementing body is lower than that of the type II cementing body;
the height of the type I cementing body is 20% -30% of that of the type II cementing body, the type I cementing body is used for deforming and yielding, and the type II cementing body is used for bearing;
the type I cementing body is a high-water-swelling material, the slurry of the type I cementing body is prepared by adding an air entraining agent and polypropylene fibers into the slurry of the type II cementing body, and the total amount of the added air entraining agent and the polypropylene fibers is not more than 3 per thousand of the total amount of the slurry of the type I cementing body;
the compression ratio of the I-type cementing body is 6-10 per mill;
the supporting method comprises the following steps:
s1, establishing a multi-layer filling body bearing structure mechanical model, and analyzing the stress characteristics of the multi-layer filling body to obtain the height of each cementing body of the multi-layer filling body;
s2, analyzing a bearing deformation mechanism of the multi-layer filling body, further obtaining the deformation characteristics of the multi-layer filling body under two working conditions, and carrying out filling by adopting a type I cementing body and a type II cementing body;
s201, dividing a working surface to be filled into two working conditions, namely a working condition I: the filling body completely adopts a II-type cementing body; working conditions are as follows: adopting a multi-layer filling body, wherein the bottom of the filling body adopts a II-type cementing body with the height of 2.5m, and the top of the filling body adopts an I-type cementing body with the height of 0.5 m;
s202, loading and applying vertical stress to the filler models in the first working condition and the second working condition respectively, obtaining a deformation curve of the filler, obtaining a high compression rate of the type I cementing body and a high strength of the type II cementing body, combining the high compression rate and the high strength to adapt to the rotary sinking of the top plate, and enhancing the stability of the filler;
s3, performing experiments and analysis on the materials of the type I cementing body and the type II cementing body in the step S2 to respectively obtain a high water swelling material and a high water quick setting material;
s301, respectively carrying out uniaxial compression tests on a PZGS sample prepared from the high-water swelling material slurry and a PTGS sample prepared from the high-water quick-setting material slurry;
s302, obtaining stress-strain curves of the two samples under uniaxial compression according to the test results of the two samples in the step S301;
s303, obtaining a multi-layer filling body formed by combining the high water swelling material and the high water quick setting material according to the stress-strain curve in the step S302;
s4, preparing high-water-speed setting material slurry of the II-type cementing body and grouting, and then preparing slurry of the I-type cementing body on the basis of the slurry of the II-type cementing body and grouting again;
and S5, monitoring the deformation of the surrounding rock of the roadway after the multi-layer position filling body is loaded in the step S4.
2. A supporting method for a multi-layer filling body bearing structure of a gob-side entry retaining of a fully mechanized caving face according to claim 1, wherein the type ii cementing body is a high-water quick-setting material consisting of two types of slurry A and B, the slurry A mainly comprises sulphoaluminate cement clinker, the slurry B mainly comprises lime gypsum, and the ratio of the two types of slurry A and slurry B is 1:1.
3. a method for supporting a multi-level filling body bearing structure of a gob-side entry retaining of a fully-mechanized caving face according to claim 1, wherein the height of the type i cementing body is 0.5m, and the height of the type ii cementing body is 2.5 m.
4. The method for supporting the gob-side entry retaining multi-level filling body bearing structure of the fully mechanized caving face according to claim 3, wherein the step S1 specifically comprises the following steps:
s101, establishing a mechanical model of a multi-layer position filling body bearing structure according to the theory of masonry beam fracture, and obtaining pressure P applied to a lower rock stratum by the rotation and sinking of an old top;
s102, according to the mechanical model of the bearing structure of the filling body obtained in the step S101, the height h of the type I cementing body is calculated1And increasing the height from 0m to 3m, obtaining a stress characteristic curve of the filling body, and synthesizing the factors of the maximum compression amount of the filling body and the material cost to obtain the height of the type I cementing body and the height of the type II cementing body.
5. The method for supporting the gob-side entry retaining multi-level filling body bearing structure of the fully mechanized caving face according to claim 3, wherein the step S4 specifically comprises the following steps:
s401, mixing the slurry A and the slurry B with water according to a water-material ratio of 1.5: 1, preparing a high-water-speed setting material, grouting to form a II-type cementing body, and stopping grouting when the grouting of the II-type cementing body reaches 2.5 m;
s402, adding an air entraining agent and polypropylene fibers on the basis of the high-water-speed setting material slurry to obtain high-water-expansion material slurry, grouting again to form a type I cementing body, and stopping grouting when the height of the type I cementing body reaches 0.5 m.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102705002A (en) * | 2012-05-12 | 2012-10-03 | 山东科技大学 | Roadside proper yielding unequal combined filling structure of gob-side entry retaining and construction method |
| CN103089300A (en) * | 2013-01-16 | 2013-05-08 | 中国矿业大学 | Structure and method for constructing multilayer heterogeneous gob-side entry retaining filling wall |
| CN103573287A (en) * | 2013-11-14 | 2014-02-12 | 山东科技大学 | Method for determining thickness of flexible material of roadside flexible-strength double-layer composite support in gob-side entry retaining |
| CN103573273A (en) * | 2013-11-14 | 2014-02-12 | 山东科技大学 | Method for suitability evaluation of high-strength material of roadside flexible-strength double-layer composite support in gob-side entry retaining |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102705002A (en) * | 2012-05-12 | 2012-10-03 | 山东科技大学 | Roadside proper yielding unequal combined filling structure of gob-side entry retaining and construction method |
| CN103089300A (en) * | 2013-01-16 | 2013-05-08 | 中国矿业大学 | Structure and method for constructing multilayer heterogeneous gob-side entry retaining filling wall |
| CN103573287A (en) * | 2013-11-14 | 2014-02-12 | 山东科技大学 | Method for determining thickness of flexible material of roadside flexible-strength double-layer composite support in gob-side entry retaining |
| CN103573273A (en) * | 2013-11-14 | 2014-02-12 | 山东科技大学 | Method for suitability evaluation of high-strength material of roadside flexible-strength double-layer composite support in gob-side entry retaining |
Non-Patent Citations (1)
| Title |
|---|
| 引气剂和聚丙烯纤维对高水材料性质的影响研究;李东华等;《中国安全生产科学技术》;20160330;第12卷(第3期);第54-59页 * |
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