CN217330921U - Safety system for thermal-combustion phase-change expansion cracking rock in rock blast hole - Google Patents

Abstract

The utility model discloses a safety system for rock blast hole internal thermal combustion phase change expansion cracking, which comprises a liquid oxygen storage and delivery device, a blast hole built-in device and a special initiator; the liquid oxygen storage and delivery device comprises a liquid oxygen storage tank and a low-temperature liquid conveying pipe communicated with the liquid oxygen storage tank; the blast hole built-in device comprises a closed cylindrical cracking pipe filled with liquid-phase carbon dioxide, a hot combustion component and sealing clay, wherein the cracking pipe, the hot combustion component and the sealing clay are sequentially filled in the blast hole from front to back; the cracking tube is a sealed cylindrical steel tube filled with liquid-phase carbon dioxide; the hot combustion assembly comprises a cylindrical PVC pipe, a hot combustion structure and an excitation assembly. The utility model discloses a rock big gun hole internal combustion phase transition inflation split rock does not adopt detonator, electric ignition head, the ignition of electric firewood fire etc. that relate to the explosive blasting and use, does not relate to easily and explodes article, has characteristics such as pollution-free, no explosive, no harmful substance, no explosion shock wave, safe high efficiency.

Description

Safety system for thermal combustion phase change expansion cracking in rock blast hole

Technical Field

The utility model relates to an engineering splits rock technical field, specifically relates to a safety coefficient that rock blasthole internal combustion phase transition inflation splits rock.

Background

The utility model discloses an applied technology patent belongs to machinery trade and sends and splits ware and blasting trade burst rock device technical field, especially relates to blasting environmental protection, blasting harmful effect, gas explosion device and advanced scientific environmental protection's applied technology worker method.

With the continuous and rapid development of Chinese economy and the continuous increase of urban processes and industrial processes, construction projects firstly relate to earth and rocky excavation, and the earth and rocky excavation needs to be blasted by using explosives. Blasting rock with explosives is a highly dangerous operation and can cause damage to the environment from vibrations, shock waves, blasting flyrock, nitrogen oxides from blasting, and other harmful gases, as well as blasting vibrations of surrounding structures. Through statistics, damage cases and complaints cases generated by blasting have more than thousands of cases with similar explosive blasting application consequences every year in China. The destructive effect of explosive explosion generates a shock earthquake effect; the blast shock wave action, the explosion of which can release huge energy instantly to generate high-temperature and high-pressure gas, so that the surrounding air is strongly vibrated, and the building is damaged or injured under the action of the shock wave within a certain range from the explosion center; the environmental hazard is caused in a considerable range by the splashing impact action of blasting fragments and blasting flystones, and the fragment scattering range of the blasting explosive is usually about 100-150 m; the thermal effect is a fire hazard effect, the explosion temperature is about 2000-3000 ℃, and the surrounding environment relates to combustible gas or explosive gas to generate a secondary hazard effect.

The development of a rock cracking device, a rock cracking technology application and a technical method for reducing environmental pollution and influence on the environment is very important and necessary for blasting operation units at present. Compared with the prior art of blasting rock by using explosives and detonators, the carbon dioxide phase change expansion rock cracking technology has the characteristics of no high temperature, small vibration, no blasting shock wave, basically no pollution, high cost, wide applicability and no need of blasting administrative approval and blasting operation approval, but the cost of blasting rock is increased by more than 120% compared with the cost of blasting by using explosives and detonators in the prior related art, and the effect can not reach the effect of explosive blasting at all. The conventional carbon dioxide phase change expansion rock cracking technology is adopted for rock cracking blasting, a potassium perchlorate and potassium permanganate igniter, a 'heating agent and heating tube' excitation structure is needed, and an oxidant and a reducing agent capable of generating a heat generation reaction are needed in advance. The common oxidants comprise sulfur, potassium nitrate, potassium perchlorate and potassium permanganate, and the common reductants comprise aluminum powder and carbon powder, wherein the potassium nitrate, the potassium perchlorate and the potassium permanganate belong to ' easily-made pipe explosion control articles ' of the ministry of public security '. The heating tube used in the application of the carbon dioxide phase change expansion rock cracking technology has the following defects: the explosion control system comprises the explosive control objects which are easy to be produced by the national ministry of public security; secondly, the heating energy is insufficient, and the complete excitation of the phase-change liquid-phase carbon dioxide cannot be met; and thirdly, the heating tube is provided with a built-in device of an electric ignition diesel head, and the electric ignition diesel head belongs to a civil explosive management and control product. Therefore, there is a need for a safe, reliable, energy efficient, heat generating device that does not require an easily detonable tube or control and does not require an electrically ignited match head to produce expanding gaseous carbon dioxide gas and energy in a safe, reliable manner to excite liquid carbon dioxide in the safest, stable manner.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a safety coefficient of rock big gun hole interior hot combustion phase transition expansion cracking rock through hot combustion formation carbon dioxide gas to utilize its energy phase transition liquid carbon dioxide, realize the expansion cracking rock, reach and make the broken rock construction of cracking rock reduce environmental pollution, reduce the effect of destroying the influence to the environment, with the problem of proposing in solving above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

a safety system for thermal combustion phase change expansion cracking rock in a rock blast hole comprises a liquid oxygen storage and delivery device, a blast hole built-in device and a special exploder;

the liquid oxygen storage and delivery device comprises a liquid oxygen storage tank and a low-temperature liquid conveying pipe communicated with the liquid oxygen storage tank;

the blast hole built-in device comprises a closed cylindrical cracking pipe filled with liquid-phase carbon dioxide, a hot combustion component and sealing clay, wherein the cracking pipe, the hot combustion component and the sealing clay are sequentially filled in the blast hole from front to back;

the cracking tube is a sealed cylindrical steel tube filled with liquid-phase carbon dioxide;

the hot combustion assembly comprises a cylindrical PVC pipe, a hot combustion structure and an excitation assembly; the hot combustion structure is provided with an oxygen injection pipe and a plurality of carbon sponges connected to the outer side of the oxygen injection pipe, the carbon sponges are cylinders made of spongy carbon substances, equal intervals are arranged between two adjacent carbon sponges, the carbon sponges are connected in series to the outer side of the pipe wall of the oxygen injection pipe, and the oxygen injection pipe is provided with a plurality of uniformly distributed drainage liquid oxygen holes on the pipe wall of the connection part of the carbon sponges; the excitation assembly is arranged in the PVC pipe and is positioned on the carbonaceous sponge body; an upper end cover and a lower end cover which are sealed integrally are arranged at two ends of the PVC pipe respectively, and a transfusion hole and a conductive hole are arranged on the upper end cover, wherein the transfusion hole is arranged in the center of the upper end cover, and the conductive hole is arranged on one side of the transfusion hole; the length of the oxygen injection pipe is greater than that of the PVC pipe, the front end of the oxygen injection pipe extends to the position of the lower end cover of the PVC pipe, and the rear end of the oxygen injection pipe extends out of the carbonaceous sponge body, penetrates out of the infusion hole of the upper end cover and is detachably connected with the low-temperature infusion pipe;

the special initiator is used for controlling the initiation of the hot combustion assembly from the outside and is electrically connected with the excitation assembly through a lead passing through the conductive hole;

during operation, liquid oxygen passes through the liquid oxygen storage and delivery device, immediately passes through the low-temperature liquid conveying pipe and the oxygen injection pipe, is soaked into the carbon sponge body through the drainage liquid oxygen hole, so that the liquid oxygen is partially gasified, then the special initiator is controlled to enable the excitation assembly to generate sparks, the carbon sponge body in the PVC pipe is ignited in a high-oxygen environment, and the combustion energy enables the fracturing pipe hermetically stored with liquid-phase carbon dioxide to crack and enables the liquid-phase carbon dioxide to be rapidly gasified.

Here, the oxygen is changed into liquid oxygen through temperature reduction and compression, the liquid oxygen has the characteristics of combustion supporting and rapid expansion, and 1.0kg of liquid oxygen can be expanded and gasified into 800 liters of oxygen instantly. The oxygen injection pipe has the function of serially connecting and consolidating a plurality of carbon sponges. The carbonaceous sponge body is made of carbon substances such as carbon black, cotton, sponge or paper pulp and the like which can absorb liquid oxygen, can absorb the liquid oxygen and is made into a cylindrical shape, the carbonaceous sponge body is connected in series in a calabash-string mode by the front end of the oxygen injection pipe to form a hot combustion structure, uncoupled interval gaps exist between the adjacent carbonaceous sponge bodies, the hot combustion structure is filled into the PVC pipe, and the manufacturing length of the carbonaceous sponge body is matched with the length of the PVC pipe in a consistent manner. The carbon substances are instantly oxidized by utilizing liquid oxygen to generate a large amount of carbon dioxide and vapor gas, and simultaneously, a large amount of heat energy is released, the generated gas reaches high temperature, the energy of the high-temperature gas is rapidly absorbed by the liquid-phase carbon dioxide cracking tube, the liquid-phase carbon dioxide rapidly changes into gaseous carbon dioxide, the liquid-phase carbon dioxide changes into gaseous carbon dioxide, the volume expansion of the gaseous carbon dioxide is more than 850 times, so that the high-pressure gaseous carbon dioxide gas generated in the blast hole generates gaseous dynamic pressure on rock mass on the wall of the blast hole, the purpose of gas expansion cracking of the rock is realized, and the rock cracking effect and the engineering purpose are achieved.

Preferably, the excitation assembly is positioned in the middle of the PVC pipe and is fixed on the oxygen injection pipe; the conducting wire comprises a positive electrode and a negative electrode which are connected with a metal conducting wire, one end of the conducting wire penetrates into the PVC pipe to be connected with the exciting assembly, and the other end of the conducting wire penetrates out of the conducting hole to be connected with the special initiator; the excitation assembly adopts a nichrome resistance heating wire, and the special initiator adopts a high-energy capacitance type charging instantaneous excitation discharger; one end of the lead is connected with the nickel-chromium alloy resistance heating wire, and the other end of the lead extends out of the PVC pipe to 1500mm outside the blast hole and is electrically connected with the high-energy capacitance type charging instantaneous excitation discharger. The electric spark is generated on the nichrome resistance heating wire through the conduction of a conducting wire, so that the carbonaceous sponge body is ignited with oxygen to generate heat energy, the liquid-phase carbon dioxide cracking tube arranged at the bottom of the blast hole is subjected to phase change effect by the heat energy generated in the hole and the high-temperature high-pressure hot carbon dioxide gas, the gaseous carbon dioxide subjected to phase change of the cracking tube and the high-temperature high-pressure hot carbon dioxide gas excited by a hot combustion structure act on rocks on the wall of the blast hole together, the rocks generate the expansion cracking effect, and the rock cracking effect and the engineering purpose are achieved.

In order to prevent excessive oxygen and overlarge pressure and facilitate the discharge and pressure relief of gasified liquid oxygen or superatmospheric liquid oxygen gas in the process of filling liquid oxygen, the upper end cover is preferably provided with an exhaust hole, the exhaust hole and the conductive hole are respectively arranged on two sides of the infusion hole, the blast hole built-in device further comprises a pressure relief exhaust pipe used for exhausting gas from the PVC pipe, the front end of the pressure relief exhaust pipe extends to the position of the lower end cover of the PVC pipe, the rear end of the pressure relief exhaust pipe extends out of the carbon sponge body and extends out of the PVC pipe from the exhaust hole of the upper end cover.

In order to prevent sparks caused by collision and the like before excitation and ensure the service life and the effect of the device, the PVC pipe is preferably a freeze-resistant ND-PVC pipe; the low-temperature infusion tube adopts a heat-resistant soft rubber tube wrapped by a stainless steel wire; the oxygen injection pipe and the pressure relief exhaust pipe are respectively made of aluminum pipes or copper pipes; the liquid oxygen storage tank adopts a welded heat-insulation low-temperature gas cylinder with an automatic heating and pressurizing device, namely the liquid oxygen storage tank which meets the standard safety of the safety law of special equipment and the supervision regulation of gas cylinder safety technology.

Preferably, the safety system further comprises a cover burst quilt which is woven by tire skins and used for safe cover protection of the fractured rock plane. The size of the covering blasting blanket is 2.0m in length and 1.2m in width, and the covering blasting blanket is used for safe covering protection of a fractured rock plane.

In order to realize better rock cracking effect, preferably, after the blast hole is drilled, the length of the PVC pipe is 25% -30% of the length of the blast hole, the length of the fracturing pipe is 25% -30% of the length of the blast hole, and the length of the filling sealing clay is 25% -30% of the length of the blast hole.

The diameters of the fracturing pipe and the PVC pipe are selected according to the diameter of a drilled blast hole, the diameters of the fracturing pipe and the PVC pipe are slightly smaller than the diameter of the drilled blast hole, preferably, the fracturing pipe is a steel pipe with two closed ends, when the diameter of the blast hole is phi 42-phi 140mm, the outer diameter of the PVC pipe is matched and configured to be phi 32-phi 110mm, the outer diameter of the fracturing pipe is matched and configured to be phi 32-phi 110mm and slightly smaller than the diameter of the blast hole, the diameter of the oxygen injection pipe is phi 5-phi 15mm, and the drainage liquid oxygen holes are uniformly arranged along the axial direction of the oxygen injection pipe at intervals of 100 mm-250 mm.

To better illustrate the present invention, there is also provided a method for using the above safety system for thermal-combustion phase-change expansion cracking rock in a rock blast hole, comprising the following steps:

s1, manufacturing a field operation surface platform and a step operation surface platform which are suitable for the safety system, namely finishing the preparation work of the work platform of the site after carrying out investigation, safety assessment and expert demonstration on the rock cracking site and the surrounding environment project.

S2, drilling blast holes on the formed step working face platform by using a drilling machine, wherein the diameter parameter of the drilling blast holes is selected to be phi 42-phi 140 mm; the drilling blast hole depth L is the sum of the height H of the created rock step working face and the exceeding depth H, namely the drilling depth L is H + H; the number n of rows of blast holes is less than or equal to 2, the number m of blast holes in each row is less than or equal to 12, and the inclination angle of the drill hole is consistent with and parallel to the inclination angle of the slope of the step surface.

And S3, arranging the liquid oxygen storage and infusion device on a field operation surface platform.

And S4, placing and arranging the sealed cylindrical fracturing pipe of the liquid-phase carbon dioxide and the blast hole built-in device from bottom to top in the blast hole. The oxygen injection pipe, the pressure relief exhaust pipe and the lead are led out of the blast hole opening. Then, filling sealing clay into the blast hole to backfill and fill the blast hole,

s5, communicating an oxygen injection pipe of the hot combustion assembly with a low-temperature liquid conveying pipe of the liquid oxygen storage and conveying device, filling liquid oxygen into the PVC pipe from the liquid oxygen storage tank through the low-temperature liquid conveying pipe and the oxygen injection pipe by adopting a hole liquid oxygen inner soaking method, and stopping filling the liquid oxygen when liquid oxygen is discharged from the opening of the pressure relief exhaust pipe.

And S6, electrically connecting the conducting wire with a special detonator through a detonation main wire.

S7, cleaning a cracked rock plane field, covering a protective safety blasting cover, and performing safety covering protection on a cracked rock working surface; setting the safety warning radius as a certain distance; and electrifying the lead and the detonator to excite the detonation.

In order to avoid artificial risks and errors and facilitate the phase change of liquid-phase carbon dioxide into gaseous carbon dioxide through experiments, measurement, observation and calculation and accurately match the liquid oxygen combustion energy required by the gaseous carbon dioxide, preferably, in the step S3, the liquid oxygen storage and delivery device is provided with a cavitation venturi tube liquid oxygen flow regulator, a liquid oxygen pump, a pressure reducing valve, a pressure relief valve and a liquid oxygen flow regulator on a liquid transfer pipe, the working pressure of the outlet of the liquid oxygen pump, namely the liquid transfer pressure, is 1.5MPa, the working pressures of the pressure reducing valve and the pressure relief valve of the oxygen storage tank are 2.5MPa, and the volume flow of the liquid oxygen injected into the PVC pipe is supplied according to 35-45% of the volume of the PVC pipe; the liquid oxygen storage tank is arranged on the working plane of the drilling platform and is 10m away from the drilling position; the oxygen storage volume V of the liquid oxygen storage tank is less than or equal to 499.0 liters, and the maximum total volume of single use is less than 300 liters.

Preferably, one end of the fracturing pipe is provided with a pressure reducing valve, a pressure relief valve and a liquid filling pipe orifice with a one-way valve, and the liquid filling pipe orifice is used for filling liquid-phase carbon dioxide into the fracturing pipe in advance, wherein the filling pressure is not more than 7.0 MPa; the working pressure of liquid-phase carbon dioxide filled into the fracturing pipe in advance is 6.5-7.0 MPa, the standard calibration values of the pressure reducing valve and the pressure relief valve of the fracturing pipe are more than 7.5MPa, and the working pressures of the pressure reducing valve and the pressure relief valve are 7.5 MPa. Here, the relief valve and relief valve are used for guaranteeing that the atmospheric pressure in the fracturing pipe can not too high, and the gas is discharged in time, guarantees safety.

Compared with the prior art, the beneficial effects of the utility model are that: the safety system and worker method of rock big gun downthehole hot combustion phase transition expansion cracking rock, utilize liquid oxygen volume rapid expansion and carbon oxygen rapid combustion, hot carbon dioxide through hot combustion formation, make liquid phase carbon dioxide send the liquid carbon dioxide gasification phase transition in the cracking tube, the inflation, send the cracking tube expansion with liquid phase carbon dioxide to burst, do work through gas expansion, make the carbon dioxide gas expansion pressure in the big gun downthehole be far greater than the tensile strength of rock, realize the expansion cracking rock, do not adopt the detonator that relates to explosive blasting and use, electric ignition head, the ignition of firewood fire etc. do not relate to easily and explode the article, have pollution-free, no explosive, no harmful substance, no explosion shock wave, characteristics such as safe high efficiency. The utility model discloses a wide application is in mining industry, geological prospecting, trades such as cement, steel and iron, electric power, subway and tunnel and municipal works, underwater engineering and emergency rescue are speedily carried out rescue work.

Drawings

FIG. 1 is a schematic structural view of a working face of a rock step according to an embodiment of the present invention;

fig. 2 is a schematic diagram of the overall structure of the embodiment of the present invention;

FIG. 3 is a schematic structural view of a hot combustion assembly according to an embodiment of the present invention;

FIG. 4 is a flow chart of oxygenation according to an embodiment of the present invention;

fig. 5 is a schematic structural view of a lower end cap according to an embodiment of the present invention;

wherein: 1. the device comprises a liquid oxygen storage device, 11 a liquid oxygen storage tank, 12 a low-temperature infusion tube, 2 a blast hole built-in device, 21 a cracking tube, 22 a hot combustion component, 23 sealing clay, 24 a pressure relief exhaust tube, 3 a special initiator, 4 PVC (polyvinyl chloride) tubes, 41 an upper end cover, 42 a lower end cover, 43 a transfusion hole, 44 a conductive hole, 45 exhaust holes, 5 an oxygen injection tube, 51 a discharge liquid oxygen hole, 6 a carbonaceous sponge body, 71 heating wires, 72 a lead, 74 an initiation main line and 8 blast holes.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1-5, the safety system for thermal-combustion phase-change expansion cracking rock in a rock blast hole 8 comprises a liquid oxygen storage and delivery device 1, a blast hole built-in device 2 and a special initiator 3;

the liquid oxygen storage and delivery device 1 comprises a liquid oxygen storage tank 11 and a low-temperature infusion tube 12 communicated with the liquid oxygen storage tank;

the blast hole built-in device 2 comprises a closed cylindrical cracking pipe 21 filled with liquid-phase carbon dioxide, a hot combustion component 22 and sealing clay 23, wherein the cracking pipe 21, the hot combustion component 22 and the sealing clay 23 are sequentially filled in the blast hole 8 from front to back; the sealing clay 23 is clay body prepared by moistening common loess with water;

the cracking tube 21 is a sealed cylindrical steel tube filled with liquid-phase carbon dioxide;

the hot combustion assembly 22 comprises a cylindrical PVC pipe 4, a hot combustion structure and an excitation assembly; the hot combustion structure is provided with an oxygen injection pipe 5 and a plurality of carbon sponges 6 connected to the outer side of the oxygen injection pipe, the carbon sponges 6 are cylinders made of spongy carbon substances, equal intervals are arranged between two adjacent carbon sponges 6, the carbon sponges 6 are connected in series to the outer side of the pipe wall of the oxygen injection pipe 5, and a plurality of uniformly distributed drainage liquid oxygen holes 51 are formed in the pipe wall of the connection part of the carbon sponges 6 of the oxygen injection pipe 5; the excitation assembly is arranged in the PVC pipe 4 and is positioned on the carbonaceous sponge body 6; an upper end cover 41 and a lower end cover 42 which are sealed integrally are arranged at two ends of the PVC pipe 4 respectively, a transfusion hole 43 and a conductive hole 44 are arranged on the upper end cover 41, wherein the transfusion hole 43 is arranged at the center of the upper end cover 41, and the conductive hole 44 is arranged at one side of the transfusion hole 43; the length of the oxygen injection pipe 5 is greater than that of the PVC pipe 4, the front end head of the oxygen injection pipe extends to the position of a lower end cover 42 of the PVC pipe 4, and the rear end head of the oxygen injection pipe extends out of the carbonaceous sponge body 6, penetrates out of a transfusion hole 43 of the upper end cover 41 and is detachably connected with the low-temperature transfusion pipe 12;

the special initiator 3 is used for controlling the initiation of the hot combustion assembly 22 from the outside and is electrically connected with the excitation assembly through a lead 72 passing through the conductive hole 44;

during operation, liquid oxygen instantly passes through the low-temperature infusion tube 12 and the oxygen injection tube 5 through the liquid oxygen storage and delivery device 1, is immersed into the carbonaceous sponge body 6 through the drainage liquid oxygen hole 51 to gasify part of the liquid oxygen, then the special initiator 3 is controlled to enable the excitation assembly to generate sparks, the carbonaceous sponge body 6 in the PVC tube 4 is ignited under the high-oxygen environment, and the combustion energy enables the cracking tube 21 hermetically storing the liquid-phase carbon dioxide phase to crack and enables the liquid-phase carbon dioxide to be gasified rapidly.

Here, the oxygen is changed into liquid oxygen through temperature reduction and compression, the liquid oxygen has the characteristics of combustion supporting and rapid expansion, and 1.0kg of liquid oxygen can be expanded and gasified into 800 liters of oxygen instantly. The oxygen injection pipe 5 has the function of serially connecting and consolidating a plurality of carbon sponges 6. Carbonaceous cavernosum 6 adopts carbon substances such as carbon black, cotton, sponge or dregs of paper that can absorb liquid oxygen to make, can absorb liquid oxygen, makes into cylindrically, is the mode of string calabash with carbonaceous cavernosum 6 with annotating the front end of oxygen pipe 5 and establishes ties into the hot combustion structure, has uncoupled interval space between the adjacent carbonaceous cavernosum 6, packs into PVC pipe 4 with the hot combustion structure, and the preparation length of carbonaceous cavernosum 6 is unanimous with 4 length matching of PVC pipe. The carbon substances are instantly oxidized by utilizing the liquid oxygen to generate a large amount of carbon dioxide and vapor gas, and simultaneously, a large amount of heat energy is released, the generated gas reaches high temperature, the energy of the high-temperature gas is rapidly absorbed by the liquid-phase carbon dioxide cracking tube 21, the liquid-phase carbon dioxide rapidly changes into gaseous carbon dioxide, the liquid-phase carbon dioxide changes into gaseous carbon dioxide, the volume expansion of the gaseous carbon dioxide is more than 850 times, so that the high-pressure gaseous carbon dioxide gas generated in the blast hole 8 generates gaseous dynamic pressure on rock mass on the wall of the blast hole 8, the purpose of gas expansion cracking of rock is realized, and the rock cracking effect and the engineering purpose are achieved.

The excitation assembly is positioned in the middle of the PVC pipe 4 and is fixed on the oxygen injection pipe 5; the conducting wire 72 comprises a positive electrode connecting metal conducting wire and a negative electrode connecting metal conducting wire, one end of the conducting wire penetrates into the PVC pipe 4 to be connected with the excitation assembly, and the other end of the conducting wire penetrates out of the conducting hole 44 to be connected with the special initiator 3; the excitation component adopts a nichrome resistance heating wire 71; the special initiator 3 adopts a high-energy capacitor type charging instantaneous excitation discharger which is a 2000V high-energy pulse discharging device and belongs to initiation devices produced according with national standards; one end of the lead 72 is connected with the nichrome resistance heating wire 71, and the other end extends out of the PVC pipe 4 to 1500mm outside the blast hole 8 and is electrically connected with the high-energy capacitance type charging instantaneous excitation discharger. Here, the electric spark is generated on the nichrome resistance heating wire 71 through the conduction of the lead 72, so that the carbonaceous sponge 6 is excited by oxygen to generate heat energy, the heat energy generated in the hole and the high-temperature and high-pressure hot carbon dioxide gas enable the liquid-phase carbon dioxide cracking tube 21 arranged at the bottom of the blast hole 8 to generate a phase change effect, the gaseous carbon dioxide causing the phase change of the cracking tube 21 and the high-temperature and high-pressure hot carbon dioxide gas excited by a hot combustion structure act on the rock on the hole wall of the blast hole 8 together, so that the rock is subjected to a cracking effect, and the purpose of rock cracking is achieved.

In order to prevent excessive oxygen and excessive pressure and facilitate the discharge and pressure relief of gasified liquid oxygen or superatmospheric liquid oxygen gas in the process of filling liquid oxygen, the upper end cover 41 is provided with an exhaust hole 45, the exhaust hole 45 and the conductive hole 44 are respectively arranged at two sides of the transfusion hole 43, the blast hole built-in device 2 further comprises a pressure relief exhaust pipe 24 for exhausting gas from the PVC pipe 4, the front end of the pressure relief exhaust pipe 24 extends to the position of the lower end cover 42 of the PVC pipe 4, the rear end of the pressure relief exhaust pipe extends out of the carbonaceous sponge body 6, and the exhaust hole 45 of the upper end cover 41 extends out of the PVC pipe 4.

In order to prevent sparks caused by collision and the like before excitation and ensure the service life and the effect of the device, the PVC pipe 4 adopts a freeze-resistant ND-PVC pipe; the low-temperature infusion tube 12 is a heat-resistant soft rubber tube wrapped by a stainless steel wire; the oxygen injection pipe 5 and the pressure relief exhaust pipe 24 are respectively made of aluminum pipes or copper pipes; the liquid oxygen storage tank 11 adopts a welded heat-insulation low-temperature gas cylinder provided with an automatic heating and pressurizing device, namely the liquid oxygen storage tank 11 which meets the standard safety of the special equipment safety law and the gas cylinder safety technical supervision regulation.

The safety system also comprises a covering blasting quilt which is woven by adopting the tire skin and is used for safe covering protection of the fractured rock plane. The size of the covering blasting blanket is 2.0m in length and 1.2m in width, and the covering blasting blanket is used for safe covering protection of a cracked rock plane.

In a cracked rock construction engineering operation site, a cracked rock construction site with the length of 105m and the width of 35m is constructed, and the engineering is a subway marshalling station foundation pit excavation construction engineering. The construction method for expanding the cracked rock safety system by utilizing the internal combustion phase change of the rock blast hole 8 specifically comprises the following steps:

s1, surveying, safety assessment and expert demonstration are carried out on a construction project site for implementing rock cracking and the surrounding environment, finishing preparation work of a working platform of the site is completed, mechanical chiseling is adopted for leveling, a rock layer step working face and a drilling platform plane are created, the length of the step working face and the drilling platform plane is 105m, the width of the step working face and the drilling platform plane is 35m, and the step working face and the drilling platform plane are consistent with the area of a rock cracking site for construction. The working height of the rock stratum step is 9.0 m. The slope angle of the formed working surface of the step is 85 degrees.

S2, drilling a blast hole 8 on a platform with the created rock working face length of 105m and the created rock working face width of 35m by using a drilling machine, wherein the diameter parameter of the drilling blast hole 8 is phi 90 mm; the depth L of the drilling blast hole 8 is 9.5 m; the number n of rows of blast holes 8 is 2; the number m of 8 blast holes in each row is 8, and the inclination angle of the drilling hole is consistent with and parallel to the inclination angle of the step working surface of 85 degrees; the distance between drilling blastholes 8 is 2.0m, and the row distance of the drilling blastholes 8 is 1.8 m; the total number of blast holes 8 is 16.

S3, the liquid oxygen storage and delivery device 1 is arranged on a platform surface with the length of 105m and the width of 35m of a field working surface, the liquid oxygen storage tank 11 is arranged at the position of the working surface of the drilling platform and is 10m away from the position of a drilling hole, and the stored liquid oxygen volume V of the liquid oxygen storage tank 11 is 499.0 liters. Manufacturing a blast hole built-in device 2: the diameter of the purchased closed cylindrical cracking tube 21 of the liquid-phase carbon dioxide and the diameter of the manufactured cylindrical PVC tube 4 are phi 80 mm; the length of the purchased closed cylindrical cracking tube 21 of liquid-phase carbon dioxide is 2.8 m; the length of a cylindrical PVC pipe 4 in the manufactured blast hole built-in device 2 is 4.0m, 10 groups of liquid discharge hole groups with 100mm of equal distance are distributed on an oxygen injection pipe 5 in a built-in heat combustion structure of the cylindrical PVC pipe 4, each liquid discharge hole group comprises 2 liquid discharge holes, and the diameter phi of each liquid discharge hole is 2mm, namely 20 liquid discharge holes are arranged; the diameter phi of a carbonaceous sponge body 6 in a built-in heat combustion structure of the cylindrical PVC pipe 4 is 75mm, the length of the carbonaceous sponge body is 4.0m, 5 sections of carbonaceous sponge bodies 6 are designed, the length of each section of carbonaceous sponge body 6 is 0.6m, and the interval gap between every two adjacent sections of carbonaceous sponge bodies 6 is 25 mm.

And S4, placing and arranging the closed cylindrical fracturing pipe 21 of the liquid-phase carbon dioxide and the blast hole built-in device 2 from bottom to top in the blast hole 8. The oxygen injection pipe 5, the pressure relief exhaust pipe 24 and the lead 72 are led out to the outside of the blast hole 8 by 1.5 m. Then, the stemming of the hole 8 was carried out by stemming the sealing clay 23 with the hole 8, and the hole 8 was clogged with the sealing clay 23 to a stemming length of 2.7 m. The diameters of the oxygen injection pipe 5 and the pressure relief exhaust pipe 24 are phi 8mm and phi 5mm respectively. After the work is finished, the oxygen injection pipe 5 is communicated and connected to the liquid oxygen storage and delivery device 1, and the low-temperature liquid conveying pipe 12 fills liquid oxygen into the blast hole built-in device 2. After observing the liquid oxygen discharged from the orifice of the pressure relief exhaust pipe 24, the operation of filling the liquid oxygen is stopped. The oxygen amount of the liquid used at this time is 249.5 liters.

S6, after the work is finished, the lead 72 is connected with the detonation main line 74 to the special detonator 3.

S7, cleaning a cracked rock plane site, covering and covering a protective safety blasting blanket, wherein the size of each covering blasting blanket is 2.0m in length and 1.2m in width, and performing safety covering protection on a cracked rock operation surface; setting the safety warning radius as 100 m; the wire 72 is electrically connected to the initiator to initiate initiation.

And S8, after detonation, generating high-temperature heat energy and high-heat high-pressure carbon dioxide in the blast hole 8 suddenly and instantaneously, and realizing the effect of expanding the cracked rock by using the carbon dioxide gas.

Taking experimental gravel rock as an example, the rock specific gravity measured by the experiment is 2.91g/cm3, the compressive strength of the measured rock is 160MPa, the tensile strength of the measured rock is 4.5MPa, the static elastic modulus is 86.0GPa, the dynamic peak pressure of the liquid-phase carbon dioxide in the blast hole 8 transformed into gaseous carbon dioxide is 86.7MPa, and the dynamic peak pressure of the gaseous carbon dioxide is far greater than the tensile strength of the rock and is smaller than the compressive strength of the rock, so that the high-pressure gaseous carbon dioxide generated in the hole can expand and burst the rock to achieve the effect of cracking the rock, and meanwhile, the bad effect of explosive blasting and rock crushing cannot be caused.

The device uses liquid oxygen heat combustion energy to make the pressure generated by the phase change of liquid phase carbon dioxide into gaseous carbon dioxide be less than the compressive strength of the rock, has no explosive shock wave effect and only has tire burst gas shock wave and sound effect, so the harm to the surrounding environment is much less than that of explosive blasting. The device can not generate strong shock waves, vibration waves, harmful and toxic gases and the like in the process of explosive blasting.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (7)

1. A safety system for thermal combustion phase change expansion cracking of rock blastholes is characterized by comprising a liquid oxygen storage and delivery device, a blasthole built-in device and a special initiator;

the liquid oxygen storage and delivery device comprises a liquid oxygen storage tank and a low-temperature liquid conveying pipe communicated with the liquid oxygen storage tank;

the blast hole built-in device comprises a closed cylindrical cracking pipe filled with liquid-phase carbon dioxide, a hot combustion component and sealing clay, wherein the cracking pipe, the hot combustion component and the sealing clay are sequentially filled in the blast hole from front to back;

the cracking tube is a sealed cylindrical steel tube filled with liquid-phase carbon dioxide;

the hot combustion assembly comprises a cylindrical PVC pipe, a hot combustion structure and an excitation assembly; the hot combustion structure is provided with an oxygen injection pipe and a plurality of carbon sponges connected to the outer side of the oxygen injection pipe, the carbon sponges are cylinders made of spongy carbon substances, equal intervals are arranged between two adjacent carbon sponges, the carbon sponges are connected in series to the outer side of the pipe wall of the oxygen injection pipe, and the oxygen injection pipe is provided with a plurality of uniformly distributed drainage liquid oxygen holes on the pipe wall of the connection part of the carbon sponges; the excitation assembly is arranged in the PVC pipe and is positioned on the carbonaceous sponge body; an upper end cover and a lower end cover which are sealed integrally are arranged at two ends of the PVC pipe respectively, a transfusion hole and a conductive hole are arranged on the upper end cover, wherein the transfusion hole is arranged in the center of the upper end cover, and the conductive hole is arranged on one side of the transfusion hole; the length of the oxygen injection pipe is greater than that of the PVC pipe, the front end of the oxygen injection pipe extends to the position of the lower end cover of the PVC pipe, and the rear end of the oxygen injection pipe extends out of the carbonaceous sponge body, penetrates out of the infusion hole of the upper end cover and is detachably connected with the low-temperature infusion pipe;

the special initiator is used for controlling the initiation of the hot combustion assembly from the outside and is electrically connected with the excitation assembly through a lead wire passing through the conductive hole.

2. The safety system according to claim 1, wherein the excitation assembly is located in the middle of the PVC pipe and is fixed on the oxygen injection pipe; the conducting wire comprises a positive electrode and a negative electrode which are connected with a metal conducting wire, one end of the conducting wire penetrates into the PVC pipe to be connected with the exciting assembly, and the other end of the conducting wire penetrates out of the conducting hole to be connected with the special initiator; the excitation assembly adopts a nichrome resistance heating wire, and the special initiator adopts a high-energy capacitance type charging instantaneous excitation discharger; one end of the lead is connected with the nickel-chromium alloy resistance heating wire, and the other end of the lead extends out of the PVC pipe and is electrically connected with the high-energy capacitance type charging instantaneous excitation discharger.

3. The safety system as claimed in claim 1, wherein the upper end cover is provided with an exhaust hole, the exhaust hole and the conductive hole are respectively arranged at two sides of the infusion hole, the blast hole built-in device further comprises a pressure relief exhaust pipe for exhausting gas from the PVC pipe, the front end of the pressure relief exhaust pipe extends to the position of the lower end cover of the PVC pipe, the rear end of the pressure relief exhaust pipe extends out of the carbon sponge body, and the exhaust hole of the upper end cover extends out of the PVC pipe.

4. A safety system according to claim 1, 2 or 3, wherein the PVC pipe is freeze resistant ND-PVC pipe; the low-temperature infusion tube adopts a heat-resistant soft rubber tube wrapped by a stainless steel wire; the oxygen injection pipe and the pressure relief exhaust pipe are respectively an aluminum pipe or a copper pipe; the liquid oxygen storage tank adopts a welded heat-insulation low-temperature gas cylinder provided with an automatic heating and pressurizing device.

5. The safety system of claim 4, further comprising a cover burst woven with a tire skin.

6. The safety system according to claim 4, wherein after drilling the blast hole, the PVC pipe has a length of 25% to 30% of the length of the blast hole, the fracturing pipe has a length of 25% to 30% of the length of the blast hole, and the stemming sealing clay has a length of 25% to 30% of the length of the blast hole.

7. The safety system as claimed in claim 4, wherein the fracturing pipe is a steel pipe with two closed ends, when the diameter of the blast hole is phi 42-phi 140mm, the outer diameter of the PVC pipe is matched and configured to be phi 32-phi 110mm, the outer diameter of the fracturing pipe is matched and configured to be phi 32-phi 110mm, and the outer diameters of the fracturing pipe are slightly smaller than the diameter of the blast hole, the diameter of the oxygen injection pipe is phi 5-phi 15mm, and the drainage liquid oxygen holes are uniformly arranged along the axial direction of the oxygen injection pipe at intervals of 100-250 mm.

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