WO2021196317A1

WO2021196317A1 - Novel combination shielding structure for preventing surrounding rock ground pressure disasters caused by mining

Info

Publication number: WO2021196317A1
Application number: PCT/CN2020/086432
Authority: WO
Inventors: 吕祥锋
Original assignee: 北京科技大学
Priority date: 2020-03-30
Filing date: 2020-04-23
Publication date: 2021-10-07
Also published as: CN111472806B; CN111472806A

Abstract

Disclosed is a novel combination shielding structure for preventing surrounding rock ground pressure disasters caused by mining. The combination shielding structure is composed of an energy-absorbing outer layer (3) and a reflective inner layer (2), and is arranged between a roadway (1) and surrounding rock (7). The surrounding rock (7) is located on the outer side of the combination shielding structure, and the roadway (1) is located on the inner side of the combination shielding structure. The reflective inner layer (2) in the novel combination shielding structure comprises the following raw materials in parts by weight: 18-24 parts of an olefin resin, 14-19.2 parts of a styrene resin, 4.8-7.2 parts of a carbon material powder, 2.1-3.2 parts of glass fibers, 1-2 parts of calcium carbonate, 1-2 parts of citric acid, 0.35-0.6 parts of tin and 17.6-23.8 parts of a silicon dioxide powder. The energy-absorbing outer layer (3) is composed of a flexible structural material having buffering and energy absorption effects. In the novel combination shielding structure, the energy-absorbing outer layer (3) can adsorb and buffer an elastic energy impact stress wave (4); the reflective inner layer (2) further buffers and reflects an incident wave; and the energy-absorbing outer layer (3) plays a role in secondary energy absorption and buffering against the reflected wave, such that secondary impact damage to the surrounding rock (7) by the reflected wave can be reduced, and a good protective effect is provided on the roadway (1).

Description

A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks

Technical field

The invention relates to the field of prevention and control of deep mining ground pressure disasters, in particular to a novel combined shielding structure used for protection of ground pressure disasters in mining surrounding rocks.

Background technique

A large amount of elastic energy will be released when a deep mining ground pressure disaster occurs. The elastic energy spread to the surrounding rock of the roadway will cause serious destruction of the roadway and casualties, which will have a significant impact on mining. At present, the protection of surrounding rock of mining roadways at home and abroad is carried out from the perspective of elastic energy absorption. There is no clear protection method for shielding elastic energy shock stress waves, and people are also conducting related researches.

Summary of the invention

The purpose of the embodiments of the present invention is to provide a new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks, which adopts a combined shielding structure plan that combines an absorbing outer layer and a reflective inner layer, which can effectively shield and protect elasticity. It can impact the stress wave to destroy the roadway.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks is arranged between the roadway and the surrounding rock. The surrounding rock is located on the outside of the roadway. The reflective inner layer is composed of an energy-absorbing outer layer made of materials with a buffering and energy-absorbing effect, and the reflective inner layer is made of a new type of porous material that reflects, disperses and buffers elastic energy shock and stress waves, and is composed of a spray filling method.

Preferably, the reflective inner layer formed by the spray filling method is an integrated structure.

Preferably, the reflective inner layer includes the following raw materials in parts by weight: 18-24 parts of olefin resin, 14-19.2 parts of styrene resin, 4.8-7.2 parts of carbon material powder, 2.1-3.2 parts of glass fiber, and 1 part of calcium carbonate. -2 parts, 1-2 parts of citric acid, 0.35-0.6 parts of tin and 17.6-23.8 parts of silica powder.

Preferably, the method for preparing the novel porous material for the reflective inner layer includes the following steps:

(1) Mix olefin resin and styrene resin, heat and melt to form a melt;

(2) Put carbon material powder, calcium carbonate, tin powder, and silica powder into a ball mill for ball milling for 5-10 hours;

(3) Add the uniformly ground powder in step (2) to the melt in step (1), and stir for 20-25 minutes;

(4) Add glass fiber to the melt and continue to stir for 20-25 minutes;

(5) Add the ground citric acid and stir for 10-15min;

(6) Maintain the temperature and keep the melt state for 40-50 minutes;

(7) The melt processed by the above steps is directly sprayed and filled on the required parts, and after natural cooling, it is solidified and formed.

Preferably, the spray filling method is to spray and fill the new porous material melt prepared above between the roadway and the energy-absorbing outer layer by spray filling, and form a reflective inner layer after curing.

Preferably, the energy-absorbing outer layer is composed of various flexible porous materials with the characteristics of light material, low density, and energy-absorbing buffer.

Specifically, in the event of a rock shock disaster, the energy-absorbing outer layer can first absorb and buffer the shock stress wave for the first time, and when the attenuated shock stress wave reaches the reflective inner layer, it is buffered and attenuated again and reflected back. The energy-absorbing outer layer can reach the surrounding rock after the second energy absorption and buffering of the energy-absorbing outer layer.

A large amount of elastic energy is released when the surrounding rock pressure disaster occurs. The elastic energy propagates to the roadway in the form of shock stress wave. The energy-absorbing outer layer absorbs and buffers the shock stress wave for the first time, and the attenuated shock stress wave reaches the reflection. When the inner layer is attenuated, it is again buffered and attenuated, and reflected back to the energy-absorbing outer layer. The energy-absorbing outer layer absorbs and buffers the reflected shock stress wave for the second time, effectively avoiding the re-damage of the surrounding rock by the reflected stress wave. , It also further protects the safety of the roadway, and can effectively avoid the roadway from being damaged by impact.

Preferably, the reflective inner layer is a porous material formed by a three-dimensional interconnected network, which has a good reflection effect on incident stress waves.

Preferably, the porous material includes a plurality of nanopores having an average cross-sectional size of up to 800 nanometers, which can further realize buffering and energy absorption.

Preferably, the carbon material powder includes at least one of carbon fiber, carbon nanotube, and carbon powder.

The present invention provides a new type of combined shielding structure for protection against ground pressure hazards in mining surrounding rocks, in particular a reflective inner layer made of a new type of porous material prepared by a new process, and an energy-absorbing outer layer. A new type of combined shielding structure for ground pressure hazards in mining surrounding rocks is formed. This structure, through the combined application of the energy-absorbing outer layer and the reflective inner layer, can well protect the roadway in the event of ground pressure disasters in deep mining and ensure life and property. Security.

Compared with the shielding layer composed of a single-layer energy-absorbing outer layer of the same thickness, the present invention sprays and fills a thinner reflective inner layer and a double-layer combined shielding structure with the energy-absorbing outer layer, which not only absorbs the energy at the incident wave stage The layer absorbs energy, and the energy is absorbed by the energy-absorbing outer layer again in the reflection stage, which prolongs the energy-absorbing time of the energy-absorbing outer layer. However, the shielding layer composed of a single-layer energy-absorbing outer layer absorbs energy only in the incident wave stage. The combined shielding structure is more effective in absorbing energy, and at the same time, it can effectively ensure the safety of the roadway by reflecting the dispersion of the inner layer on the stress wave.

Compared with the shielding layer composed of a single-layer reflective inner layer, the double-layer combined shielding structure of the present invention can effectively eliminate the secondary damage of the surrounding rock caused by the reflected wave through the secondary energy absorption of the energy-absorbing outer layer of the reflected wave. The reflected wave generated by the reflection of the shielding layer formed by the inner layer of the layer reflection will cause secondary damage to the surrounding rock, so the double-layer combined shielding structure of the present invention can effectively avoid the secondary damage of the surrounding rock.

In addition, the present invention uses spray filling to construct the reflective inner layer, avoiding excessive use of fixing devices during the shielding layer setting process. Due to the influence of the surrounding rock structure and other factors, too many fixing devices may sometimes cause damage to the surrounding rock, and The shielding layer combined completely by the fixing device has a low degree of integration, which will reduce its shielding and protection effect in actual use. Therefore, the present invention uses a spray filling method to set a reflective inner layer to realize the combined shielding structure into an integrated structure, which also solves the problem. One of the difficult problems of the multi-layer shielding combination structure in the actual setting.

The beneficial effects of the present invention mainly include:

① Compared with the existing porous materials, the new material used in the reflective inner layer of the present invention has a good reflection effect on shock stress waves and a better effect on dispersing stress waves;

②The cost of raw materials used in the reflective inner layer is not high, and the preparation process is simplified, which is suitable for promotion;

③The new porous material of the reflective inner layer can be used by spray filling method. The reflective inner layer formed by spray filling has a higher degree of integration, the effect of dispersing and reflecting stress waves is better, and the use is simpler and more convenient;

④ The new combined shielding structure, through the absorption and buffering of the elastic energy shock stress wave of the energy-absorbing outer porous material and the reflection of the reflective inner layer, the shock stress wave will go through many times during the process of reaching and leaving the combined shielding structure. Energy absorption and buffering can not only effectively protect the roadway from being damaged by the shock stress wave, but also avoid the secondary damage to the surrounding rock caused by the reflected stress wave, which can achieve a better roadway safety guarantee effect;

⑤ The new type of combined shielding structure, which combines energy-absorbing and reflective materials, is the first time in the application of shielding structure, and it is worthy of further research and promotion.

Therefore, the combined shielding structure composed of the reflective inner layer and the energy-absorbing outer layer of the present invention has good application prospects and popularization value.

Description of the drawings

Figure 1 is a structural schematic diagram of a new type of combined shielding structure used for mining surrounding rock and ground pressure disaster protection,

Among them: 1-roadway, 2-reflective inner layer, 3-energy absorbing outer layer, 4-shock stress wave, 5-incident wave, 6-reflected wave, 7-surrounding rock;

Figure 2 is a flow chart of the preparation process of the new porous material for the reflective inner layer in the new combined shielding structure.

Detailed ways

In order to better understand the technical solutions of the present invention, the following describes the embodiments of the present invention in detail with reference to the accompanying drawings.

It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

Example 1

Equipment needed: pressure sensor (measure the peak pressure of the impact stress wave at different positions of the shielding structure), support body (support the fixed test sample), shock stress wave blocking device (used to block the direct impact stress of the explosion when detecting the reflected stress wave) Impact of waves), explosives with specified performance (select spherical TNT), explosive suspension brackets and other related equipment. In addition, the ground of the test site needs to be hardened or padded with steel plates.

Local stress wave impact test: The test sample selects a 10cm-thick reflective inner layer of new porous material board, the length and width are 100cm, 500gB explosive, the test distance is 1 meter, and the barrier baffle is set 2cm in front of the new porous material board. The plate is facing the center of the new porous material plate with a circular hole with a radius of 5 cm. The barrier baffle and the backing plate are fixed by the support. There are pressure sensors at the position of the small holes in the barrier and between the new porous material plate and the backing plate. Among them, there is pressure sensor No. 1 on the front of the small hole new porous material plate, and the back of the new porous material plate facing the No. 1 sensor. Pressure sensor No. 2 is installed. No. 3, 4, and No. 5 pressure sensors are set at a radiation distance of 10cm in the positive triangle around No. 2 position, No. 6, 7, and No. 8 pressure sensors are set at 20cm, and No. 9, 10, and 11 pressure sensors are set at 30cm. Test results: The peak pressure at No. 1 position is 0.51 MPa, No. 2 is 0.08 MPa, No. 3 is 0.07 MPa, No. 4 is 0.06 MPa, No. 5 is 0.07 MPa, No. 6 is 0.05 MPa, No. 7 is 0.06 MPa, No. 8 It is 0.05 MPa, No. 9 is 0.04 MPa, No. 10 is 0.04 MPa, and No. 11 is 0.03 MPa.

The test shows that the reflective inner layer of the new porous material plate in the combined shielding structure has good rigidity and can effectively disperse the impact of local stress waves, avoiding the damage of the local roadway caused by the stress wave impact of the mining surrounding rock pressure disaster. And cause serious consequences.

Example 2

Reflective inner layer reflection test: The test sample is a 10cm-thick reflective inner layer new porous material plate, 500gB explosive, and the test distance is 1 meter. The new porous material plate is attached to the support fixed by the support, on the front of the new porous material plate. , Between the back of the new porous material board and the backing board, at a distance of 0.5 meters from the reflective surface blocked by the barrier device, there are

pressure sensors

1, 2 and 3 respectively. The test results show that the peak pressure at position 1 is 0.52MPa, and the peak pressure at position 2. It is 0.26MPa, and No. 3 is 0.34MPa.

Experiments show that the reflective inner layer material has stress wave reflection characteristics.

Example 3

Comparison test between commercially available foamed aluminum material and new porous material board: Commercially purchased foamed aluminum material of the same size and thickness and the new porous material board of the present invention, the test conditions are the same as in Example 2, the new porous material board, the result is, No. 1 position The peak pressure is 0.51MPa, No. 2 is 0.21MPa, No. 3 is 0.32MPa; foam aluminum material board, the result is that the peak pressure of No. 1 position is 0.50MPa, No. 2 is 0.33MPa, No. 3 is 0.03MPa;

The comparative test shows that the reflective inner layer material has significantly better stress wave reflection performance than commercially available materials.

Example 4

Tin addition test: discard the tin in the raw material composition of the new porous material, and make the porous material plate with the same composition of other raw materials. The experimental conditions are the same as in Example 2. The test result is that the peak pressure at position 1 is 0.51 MPa, and the peak pressure in No. 2 is 0.36. MPa, No. 3 is 0.03MPa;

Tin substitution test: The tin material in the new porous material composition is replaced with aluminum and zinc. Under the same conditions, when replaced with aluminum, the test result is that the peak pressure at position 1 is 0.51 MPa, and the peak pressure at position 2 is 0.30 MPa, 3. No. is 0.14MPa; when changing to zinc, the result is that the peak pressure at No. 1 position is 0.50 MPa, No. 2 is 0.29 MPa, and No. 3 is 0.12 MPa;

Experiments show that tin in the raw material of the reflective inner layer has a strong influence on the reflective properties.

Example 5

Energy-absorbing outer layer and reflective inner layer combination test: In the present invention, the 20cm-thick energy-absorbing outer layer and the 10cm-thick reflective inner layer are laminated to form a 30cm-thick combined shielding structure. Cut into squares of the same size and follow the test method of Example 2. The test result is that the combined shielding structure has a peak pressure of 0.51 MPa at No. 1 position, 0.02 MPa at No. 2 and 0.03 MPa at No. 3; foamed aluminum structure, the result is The peak pressure at No. 1 position is 0.50 MPa, No. 2 is 0.21 MPa, and No. 3 is 0.03 MPa;

Tests show that the combined shielding structure composed of the energy-absorbing outer layer and the reflective inner layer of the present invention has good stress wave protection performance, which is better than that of commercially available materials.

Example 6

A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks, as shown in Figure 1, is set between the roadway 1 and the surrounding rock 7. The surrounding rock 7 is located outside the roadway 1, and is characterized in that: The combined shielding structure is composed of an energy-absorbing outer layer 3 and a reflective inner layer 2. The energy-absorbing outer layer 3 is composed of a material with a buffering and energy-absorbing effect. The porous material is constructed by spray filling.

The reflective inner layer 2 includes the following raw materials by weight: 18 parts of olefin resin, 14 parts of styrene resin, 4.8 parts of carbon material powder, 2.1 parts of glass fiber, 1 part of calcium carbonate, 1 part of citric acid, 0.35 parts of tin and 17.6 parts of silica powder;

The process of making the above-mentioned parts by weight of the raw materials into the new porous material used in the reflective inner layer 2:

(1) Mix olefin resin and styrene resin, and heat to 175°C to melt to form a melt;

(2) Put carbon material powder, calcium carbonate, tin powder, and silica powder into the ball mill for ball milling for 5 hours;

(3) Add the uniformly ground powder in step (2) to the melt in step (1), and stir for 20 minutes;

(4) Add glass fiber to the melt and continue stirring for 20 minutes;

(5) Add the ground citric acid and stir for 10 minutes;

(6) Maintain the temperature and maintain the melt state for 40 minutes.

After the above process, a new type of porous material used for spraying the reflective inner layer 2 can be obtained. The energy-absorbing outer layer 3 can be made of commercially available foamed aluminum material with a thickness of 30cm. , And then pave the roadway, the distance between the roadway and the foamed aluminum is controlled to be about 10cm, and the new porous material is sprayed between the roadway and the foamed aluminum. After natural cooling and solidification, it forms a combined shielding structure with the energy-absorbing outer layer. In actual operation, according to the actual situation, the appropriate thickness of the energy-absorbing outer layer material and the appropriate thickness of the reflective inner layer material can be selected to achieve effective protection. During the construction of the new type of combined shielding structure, isolation and support molds can be erected between the roadway and the aluminum foam layer according to actual needs. The combined shielding structure can effectively protect the roadway from damage to the roadway and the enclosure caused by rock bursts when mining deep underground. The secondary damage of the rock has a good protective effect on the safety of life and property.

Example 7

A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks, wherein the reflective inner layer 2 includes the following raw materials by weight:

24 parts of olefin resin, 19.2 parts of styrene resin, 7.2 parts of carbon material powder, 3.2 parts of glass fiber, 2 parts of calcium carbonate, 2 parts of citric acid, 0.6 parts of tin, and 23.8 parts of silica powder

(1) Mix olefin resin and styrene resin, and heat to 170°C to melt to form a melt;

(2) Put carbon material powder, calcium carbonate, tin powder, and silica powder into a ball mill for 10 hours;

(3) Add the uniformly ground powder in step (2) to the melt in step (1), and stir for 25 minutes;

(4) Add glass fiber to the melt and continue to stir for 25 minutes;

(5) Add the ground citric acid and stir for 15 minutes;

(6) Maintain the temperature and maintain the melt state for 50 minutes.

After the above process, a new type of porous material for spraying the reflective inner layer 2 can be obtained. The energy-absorbing outer layer 3 can be made of commercially available reinforced polyurethane foam with a thickness of 35 cm. Then pave the roadway on the rock. The distance between the roadway and the reinforced polyurethane foam is controlled to be about 10cm. The new porous material is sprayed between the mold and the reinforced polyurethane foam. After natural cooling and solidification, it forms a combined shielding structure with the energy-absorbing outer layer. . In actual operation, according to the actual situation, the appropriate thickness of the energy-absorbing outer layer material and the appropriate thickness of the reflective inner layer material can be selected to achieve effective protection. During the construction of the new combined shielding structure, isolation and support molds can be erected between the roadway and the reinforced polyurethane foam layer as required. The combined shielding structure can effectively protect the roadway from damage and damage caused by rock impact when mining deep underground. The secondary damage to the surrounding rock has a good protective effect on the safety of life and property.

Example 8

22 parts of olefin resin, 16 parts of styrene resin, 5.5 parts of carbon material powder, 2.5 parts of glass fiber, 1.5 parts of calcium carbonate, 1.5 parts of citric acid, 0.45 parts of tin, and 20.5 parts of silica powder;

(2) Put carbon material powder, calcium carbonate, tin powder, and silica powder into a ball mill for ball milling for 8 hours;

(3) Add the uniformly ground powder in step (2) to the melt in step (1), and stir for 22 minutes;

(4) Add glass fiber to the melt and continue to stir for 22 minutes;

(5) Add the ground citric acid and stir for 12 minutes;

(6) Maintain the temperature and maintain the melt state for 45 minutes.

After the above process, a new type of porous material for the jet reflective inner layer 2 can be obtained. The energy-absorbing outer layer 3 can be made of a commercially available foamed aluminum material with a thickness of 35cm. , And then pave the roadway, the distance between the roadway and the foamed aluminum is controlled at about 15cm, and the new porous material is sprayed between the roadway and the foamed aluminum. After natural cooling and solidification, it forms a combined shielding structure with the energy-absorbing outer layer. In actual operation, according to the actual situation, the appropriate thickness of the energy-absorbing outer layer material and the appropriate thickness of the reflective inner layer material can be selected to achieve effective protection. During the construction of the new combined shielding structure, isolation and support molds can be erected between the roadway and the aluminum foam layer as required. The combined shielding structure can effectively protect the roadway from damage to the roadway and surrounding rock by the rock burst when mining deep underground. The secondary damage has a very good protective effect on the safety of life and property.

In addition, it should be understood that although this specification is described in accordance with the implementation manners, not each implementation manner only includes an independent technical solution. This narration in the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole The technical solutions in the various embodiments can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims

A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks is arranged between the roadway and the surrounding rock. The surrounding rock is located on the outside of the roadway. The reflective inner layer is composed of an energy-absorbing outer layer made of materials with a buffering and energy-absorbing effect, and the reflective inner layer is made of a new type of porous material that reflects, disperses and buffers elastic energy shock and stress waves, and is composed of a spray filling method.
A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, characterized in that the reflective inner layer formed by the spray filling method is an integrated structure.
A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, wherein the reflective inner layer comprises the following raw materials in parts by weight: 18-24 parts by weight of olefin resin, benzene 14-19.2 parts of vinyl resin, 4.8-7.2 parts of carbon material powder, 2.1-3.2 parts of glass fiber, 1-2 parts of calcium carbonate, 1-2 parts of citric acid, 0.35-0.6 parts of tin, and 17.6-23.8 parts of silica powder share.
A novel combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 2, characterized in that the preparation method of the new porous material of the reflective inner layer comprises the following steps:

(1) Mix olefin resin and styrene resin, and heat to melt to form a melt;

(2) Put carbon material powder, calcium carbonate, tin powder, and silica powder into a ball mill for ball milling for 5-10 hours;

(3) Add the uniformly ground powder in step (2) to the melt in step (1), and stir for 20-25 minutes;

(4) Add glass fiber to the melt and continue to stir for 20-25 minutes;

(5) Add the ground citric acid and stir for 10-15min;

(6) Maintain the temperature and keep the melt state for 40-50 minutes;

(7) The melt processed by the above steps is directly sprayed and filled on the required parts, and after natural cooling, it is solidified and formed.
A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, wherein the spray filling method is to use the new porous material melt prepared in claim 4 by spray filling method. Spray filling between the roadway and the energy-absorbing outer layer, and form a reflective inner layer after curing.
A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, characterized in that the energy-absorbing outer layer is made of various light materials, low density, and energy-absorbing characteristics. Made of flexible porous material.
A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, characterized in that, in the event of a rock burst disaster, the energy-absorbing outer layer can first absorb and Buffer shock stress wave. When the attenuated shock stress wave reaches the reflection inner layer, it is buffered and attenuated again, and is reflected back to the energy-absorbing outer layer. After the second energy absorption and buffering of the energy-absorbing outer layer, it can reach the surrounding rock.
A new type of combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, wherein the reflective inner layer is a porous material formed by a three-dimensional interconnection network, which has good resistance to stress incident waves. Reflection effect.
The novel combined shielding structure for protection against ground pressure disasters in mining surrounding rocks according to claim 1, wherein the reflective inner layer material comprises a plurality of nanopores with an average cross-sectional size of up to 800 nanometers. , Can further realize buffering and energy absorption.
The novel combined shielding structure for protection against ground pressure disasters of mining surrounding rocks according to claim 3, wherein the carbon material powder comprises at least one of carbon fiber, carbon nanotube and carbon powder.