Device and tunneling method for multiple transient fracturing of rocks based on water hammer effect

Abstract

The invention discloses a device and a tunneling method for multiple transient fracturing of rocks based on the water hammer effect, belonging to the field of static fracturing mining. It mainly consists of a high-pressure water supply system and a water hammer fracturing system. The high-pressure water supply system is composed of a high-pressure resistant water bucket, a one-way valve, a hydraulic pump, a switching valve, a high-pressure resistant hard pipe, a pressure gauge, a pressure relief valve, etc. The water hammer fracturing system is composed of a fracturing rod main body, a high-pressure resistant and highly elastic hose, a self-locking valve, a fracturing assembly module, etc. The device utilizes the principle that when a high-speed fluid inside a pipeline is suddenly stopped during the flowing process, a huge pressure is generated on the valve and the pipe wall. By pressurizing in a specially made high-pressure resistant water bucket, the flow rate of the water in the pipeline is maintained, and at the same time, different pipe diameters are set for pipelines with different functions, which can not only ensure the fracturing effect, but also ensure the service life of the equipment pipeline through different flow rates.

Description

Technical Field

[0001] The present invention belongs to the technical field of transient fracturing mining, and particularly relates to a device and a tunneling method for multiple transient fracturing of rocks based on the water hammer effect. Background Technique

[0002] For the tunneling in some underground mines and underground projects, it is generally carried out by shield machines, roadheaders, etc. However, due to the limited construction conditions and the inability to introduce large machinery to assist in tunneling, it can only be carried out by the method of drill and blast cut. The methods of drill and blast cut mainly include explosive blasting tunneling, impact hammer rock breaking, gas blasting rock breaking, hydraulic technology rock breaking, etc. These several methods of drill and blast cut have their own advantages and disadvantages. The drill and blast cut tunneling initially adopted explosive blasting tunneling. With the development of explosive production technology, more and more mine explosives have been developed. However, the storage of explosives in underground mines has very strict regulations. Even when using them, they need to be transported from the surface to the underground and require professional operation. Although mine explosives can avoid gas accidents, there are still problems such as overexcavation, under-excavation, and excessive disturbance of the surrounding rock layers when using mine explosives for drill and blast cut. Moreover, the amount of explosives used is not easy to control. If the amount used is small, the effect is not ideal. If the amount used is large, there may be situations such as flying rocks and overexcavation. And it is necessary to specially ventilate the dust generated by explosive blasting into the atmosphere, which not only delays the construction progress but also pollutes the environment by discharging the dust into the atmosphere.

[0003] Impact hammer rock breaking causes greater harm to workers' bodies and has a slower construction progress; gas blasting rock breaking is a new rock breaking method at present, but it also needs to be detonated by explosives and there are also situations such as overexcavation, under-excavation, and flying rocks. Although hydraulic technology rock breaking can avoid problems such as overexcavation, under-excavation, and flying rocks, hydraulic rock breaking belongs to static rock breaking, and most of the broken rocks are whole rocks, which need to be driven with anchor bolts and then broken again with pneumatic picks and impact hammers, which undoubtedly increases the labor intensity of workers and slows down the construction speed. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and a tunneling method for multiple transient fracturing of rocks based on the water hammer effect.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A device for multiple transient fracturing of rocks based on the water hammer effect, comprising a high-pressure water supply system and a water hammer fracturing system connected thereto. The water hammer fracturing system includes a fracturing rod body. A cavity for accommodating a first high-pressure hard pipe is provided at the center of the fracturing rod body. Four trapezoidal grooves are provided on the outer periphery of the fracturing rod body along its length direction, and the included angle between adjacent trapezoidal grooves is a right angle. An outlet communicating with the cavity is provided at the bottom of each trapezoidal groove. A fracturing assembly module matching its shape is provided in each trapezoidal groove. A high-pressure and high-elasticity hose accommodating cavity is provided at the bottom of each fracturing assembly module. The surface of the fracturing module can be provided with cylindrical, pointed conical, etc. to ensure the fracturing effect. A high-pressure and high-elasticity hose with one end communicating with the first high-pressure hard pipe through the outlet is provided in the accommodating cavity. The other end outlet of the high-pressure and high-elasticity hose is connected to a self-locking valve body through a second high-pressure hard pipe. The self-locking valve body includes a barrel-shaped body. An opening is provided at the top of the barrel-shaped body. A circular floating lid is provided inside the barrel-shaped body. The outer diameter of the lid is larger than the inner diameter of the opening. Since the self-locking valve has the shape of a small water bucket, the upper opening is smaller than the barrel wall, and a lid with a floating float is provided inside the bucket. When high-pressure water flows into the self-locking valve through the fracturing rod body and the high-pressure and elastic hose, the lid is lifted by the buoyancy of the water. When the water inside the bucket is about to be full, the lid fits with the upper opening to complete self-locking. At this time, since the water flowing at high speed inside the high-pressure and elastic hose is suddenly stopped, a water hammer effect is generated.

[0007] Further, the high-pressure water supply system includes a high-pressure resistant water tank. An opening is provided at the top of the high-pressure resistant water tank. A plunger valve is provided inside the high-pressure resistant water tank. The top of the plunger valve is connected to a second pressure surface through a connecting rod. A first pressure surface is provided at the top of the second pressure surface. The first pressure surface is fixedly connected to the outer wall of the high-pressure resistant water tank through a fixing rod. A hydraulic pump is provided between the first pressure surface and the second pressure surface. The hydraulic pump is placed between the first pressure surface and the second pressure surface, and a manual hydraulic pump and an electric hydraulic pump can be selected according to the working conditions. By pressurizing the water stored inside the high-pressure resistant water tank between the two pressure surfaces, the water outlet at the bottom of the high-pressure resistant water tank is connected to the high-pressure and high-elasticity hose inside the fracturing rod body through a first high-pressure hard pipe.

[0008] Further, a switch valve, a pressure relief valve and a check valve are sequentially provided on the first high-pressure hard pipe. The direction of water flow allowed by the check valve is from the high-pressure resistant water tank to the fracturing module. Its function is to reduce the impact on the high-pressure resistant water tank and the hydraulic pump when a water hammer effect occurs in the front, and at the same time prevent the liquid from flowing back and damaging the device. The switch valve is provided to open the switch valve to control the water to flow out of the high-pressure resistant water tank when the internal pressure of the high-pressure resistant water tank reaches the set requirement; the pressure relief valve is provided between the check valve and the high-pressure resistant water tank. When the water flow reaches the required flow rate and the self-locking valve closes, the pressure relief valve can relieve the high pressure generated by the water hammer before the pressure relief valve; an inlet is also provided at the bottom of the high-pressure resistant water tank, and a pressure relief valve is also provided on the second high-pressure hard pipe.

[0009] Furthermore, a buffer structure is provided in the accommodation cavity at the bottom of the fracturing assembly module to protect the high-pressure resistant elastic hose.

[0010] A tunneling method for a device for multiple transient fracturing of rocks based on the water hammer effect includes the following steps: S1. Drill fracturing holes and fracturing auxiliary holes on the excavation face through a drilling rig, and place the device into the fracturing holes.

[0011] S2. Close the water outlet valve of the high-pressure resistant water bucket, connect all components at the same time, and fill the high-pressure resistant water bucket with water.

[0012] S3. Pressurize the water in the high-pressure resistant water bucket through the hydraulic pump between the first pressurizing surface and the second pressurizing surface until the pressure gauge shows 10 MPa, then stop pressurizing, open the water outlet valve, the water flows through the high-pressure resistant elastic hose and then into the self-locking valve. When the self-locking valve closes, a high-intensity water hammer effect appears inside the high-pressure resistant elastic hose, and the elastic hose instantly expands to drive the assembly module to generate high pressure with the fracturing hole wall, breaking the coal body or rock mass.

[0013] S4. Open the pressure relief valve, refill the water in the self-locking valve into the high-pressure resistant water bucket for reuse, and repeat steps S2 - S3 until a free face is formed around the fracturing hole.

[0014] S5. Repeat steps S2 - S4 until all the rocks around the preset fracturing holes are dug out, support and spray mortar, and enter the next cycle.

[0015] The advantages of the present invention are as follows: The present invention utilizes the principle that when a high-speed fluid inside a pipeline is suddenly stopped during the flow process, a huge pressure is generated on the valve and the pipe wall (dozens or even hundreds of times the pressure of the water flow itself). The high-pressure water flows out from a specially made high-pressure resistant water tank, flows through pipes with different apertures into a high-pressure resistant and highly elastic hose, and then into a self-locking valve. When the self-locking valve is filled with water, the self-locking valve automatically locks. The water flowing at high speed in the high-pressure resistant elastic hose is intercepted, generating a water hammer effect. The pressure in the highly elastic hose instantly increases. Since the main body of the fracturing rod is slightly smaller than the diameter of the fracturing hole, the highly elastic hose expands and is blocked by the rocks around the fracturing hole, and the high pressure generated inside is instantly loaded onto the rocks around the fracturing hole, causing the surrounding rocks to break. Compared with the traditional method, the loading energy is controllable, and phenomena such as overexcavation, under-excavation, and flying rocks will not occur. Moreover, the instantaneous loading will cause a higher degree of fragmentation of the surrounding rocks, eliminating the need for secondary fracturing and other processes, improving the tunneling efficiency; it provides a brand-new idea for tunneling and cut blasting in roadways and tunnels, with low cost and simple operation, and is conducive to popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Structural schematic diagram of the device of the present invention;

[0017] Figure 2It is a schematic diagram of the main structure of the fracturing rod in the present invention;

[0018] Figure 3 It is a schematic diagram of the fracturing assembly module in the present invention;

[0019] Figure 4 It is a layout diagram of the fracturing holes and auxiliary fracturing holes in the present invention;

[0020] Figure 5 It is a fracturing effect diagram of the present invention;

[0021] Figure 6 It is a structural diagram of the present invention after taking out the first piece of face rock. Detailed implementation manners

[0022] As shown in the figure, a device for multiple transient fracturing of rocks based on the water hammer effect includes a high-pressure water supply system and a water hammer fracturing system connected thereto. The water hammer fracturing system includes a fracturing rod main body 15. A cavity for accommodating a first high-pressure hard pipe 10 is provided at the center of the fracturing rod main body 15. Four trapezoidal grooves are provided along the length direction on the outer periphery of the fracturing rod main body. The included angle between adjacent trapezoidal grooves is a right angle. An outlet communicating with the cavity is provided at the bottom of each trapezoidal groove. A fracturing assembly module 16 matching its shape is provided in each trapezoidal groove. A high-pressure and high-elasticity hose accommodating cavity is provided at the bottom of each fracturing assembly module. The surface of the fracturing module can be provided with cylindrical, pointed conical, etc. to ensure the fracturing effect. A high-pressure and high-elasticity hose 17 with one end communicating with the first high-pressure hard pipe 10 through the outlet is provided in the accommodating cavity. The other end outlet of the high-pressure and high-elasticity hose is connected to a self-locking valve main body 12 through a second high-pressure hard pipe 11. The self-locking valve main body includes a barrel-shaped body 13. An opening is provided at the top of the barrel-shaped body. A circular floating lid 14 is provided inside the barrel-shaped body. The outer diameter of the lid is larger than the inner diameter of the opening. Since the shape of the self-locking valve main body is a small water bucket, the upper opening is smaller than the barrel wall, and a lid with a floating body is provided inside the bucket. When high-pressure water flows into the self-locking valve through the fracturing rod main body and the high-pressure and high-elasticity hose, the lid is lifted by the buoyancy of the water. When the water inside the bucket is almost full, the lid fits with the upper opening to complete self-locking. At this time, since the high-speed flowing water inside the high-pressure and high-elasticity hose is suddenly stopped, a water hammer effect is generated; The high-pressure water supply system includes a high-pressure resistant water tank 4. An opening is provided at the top of the high-pressure resistant water tank. A plunger valve 6 is provided inside the high-pressure resistant water tank. The top of the plunger valve is connected to a second pressure surface 3 through a connecting rod. A first pressure surface 1 is provided at the top of the second pressure surface 3. The first pressure surface is fixedly connected to the outer wall of the high-pressure resistant water tank 4 through a fixing rod 5. A hydraulic pump 2 is provided between the first pressure surface and the second pressure surface. The hydraulic pump is placed between the first pressure surface and the second pressure surface. A manual hydraulic pump and an electric hydraulic pump can be selected according to the working conditions. The water stored inside the high-pressure resistant water tank is pressurized between the two pressure surfaces. The outlet at the bottom of the high-pressure resistant water tank is connected to the high-pressure and high-elasticity hose inside the fracturing rod main body through a first high-pressure hard pipe; A switch valve 7, a pressure relief valve 8 and a check valve 9 are sequentially provided on the first high-pressure hard pipe. The direction of water flow allowed by the check valve is from the high-pressure resistant water tank to the fracturing module. Its function is to reduce the impact on the high-pressure resistant water tank and the hydraulic pump when a water hammer effect occurs in the front, and at the same time prevent the liquid from flowing back and breaking the device. The switch valve is provided to open the switch valve when the pressure inside the high-pressure resistant water tank reaches the set requirement to control the water to flow out of the high-pressure resistant water tank; The pressure relief valve is provided between the check valve and the high-pressure resistant water tank. When the water flow reaches the required flow rate, the self-locking valve closes, and the pressure relief valve can release the high pressure generated by the water hammer before the pressure relief valve; An inlet is also provided at the bottom of the high-pressure resistant water tank. A pressure relief valve is also provided on the second high-pressure hard pipe; A buffer structure 18 is provided in the accommodating cavity at the bottom of the fracturing assembly module to protect the high-pressure and high-elasticity hose.

[0023] A tunneling method for a device for multiple transient fracturing of rocks based on the water hammer effect, comprising the following steps:

[0024] First step, arrange fracturing holes 20 and fracturing auxiliary holes 21 on the excavation face 19 through a drilling rig, and the arrangement method of the fracturing holes and fracturing auxiliary holes is as Figure 4 ;

[0025] Second step, place the fracturing device into the No. 1 fracturing hole;

[0026] Third step, close the water outlet valve 7 of the high-pressure water bucket, and at the same time connect all components, and fill the special high-pressure resistant water bucket with water;

[0027] Fourth step, pressurize the water in the special high-pressure resistant water bucket 4 through the hydraulic pump 2 between the first pressurizing surface 1 and the second pressurizing surface 3 until the pressure gauge shows 10 MPa (selected according to the actual working conditions), and then stop pressurizing;

[0028] Fifth step, open the water outlet valve 7 of the special high-pressure water bucket, and the water flow flows from the water outlet valve 7 and the one-way valve 9 to the main body 15 of the fracturing rod;

[0029] Sixth step, the water flow flows into the self-locking valve main body 12 through the internal cavity of the fracturing rod and the elastic high-pressure resistant hose 17. When the water volume inside the self-locking valve main body reaches its capacity, the self-locking valve main body closes, and a high-intensity water hammer effect appears inside the elastic high-pressure resistant hose 17. The elastic hose instantaneously expands, driving the assembly module 16 to generate high pressure with the fracturing hole wall, crushing the coal body or rock mass;

[0030] Seventh step, open the pressure relief valve 8, and re-add the water in the self-locking valve main body 12 into the special high-pressure resistant water bucket 4;

[0031] Eighth step, repeat steps three, four, five, and six;

[0032] Ninth step, when the degree of fragmentation of the coal and rock mass is relatively high, take out the fragmented rock or coal around the No. 1 fracturing hole, and form a free face on the side of other fracturing holes;

[0033] Tenth step, repeat steps three, four, five, six, seven, and eight until all the rocks around the preset fracturing holes are taken out;

[0034] Eleventh step, support and spray mortar, and enter the next cycle.

[0035] Since the pressure generated by the water hammer effect is controllable, problems such as overexcavation, under-excavation, and flying rocks are perfectly avoided. At the same time, there is no need for a secondary crushing process, improving the tunneling work efficiency. At the same time, due to its simple structure, it can meet the use under various complex conditions.

[0036] The accounting process involved in the present invention is as follows:

[0037] According to Bernoulli's equation

[0038] where P is the static pressure with the unit of Pa; ρ is the density of water with the unit of 1000 kg / m 3 ; H is the height with the unit of n; V is the average fluid flow velocity with the unit of m / s; C is a constant without a unit. Considering the entire system as a whole, the water pressure in the water bucket is 10 Mpa = 10×10 6 Pa, the height of the water flow in the system is negligible, and the atmospheric pressure at the outlet is taken as 0.1013 MPa.

[0039] According to Bernoulli's equation:

[0040] where P1 = 10×10^6 Pa; P2 = 1.013×10 5 Pa; approximately h1 = h2; v1 = 0

[0041] Substituting the data, we get v2 = 140.703 m / s. Since the water flows out from four outlets, the water flow velocity at each outlet is v3 = v2 / 4 = 35.18 m / s;

[0042] The pressure change caused by water hammer is: ΔP = V w ×ΔV×ρ×10 -5

[0043] where is the pressure wave velocity calculation formula; ρ is the medium density, for water it is 100 kg / m 3 , K is the volume elastic modulus of the medium in the pipeline, the value of K for water is generally 2.19×10 9 Pa, t is the pipeline wall thickness with the unit of mm, di is the pipeline inner diameter with the unit of mm; ΔV refers to the change in the medium flow velocity. For the water hammer caused by valve closure, ΔV is equal to the operating flow velocity; E is the elastic modulus of the pipeline material; setting the inner diameter of the high-elastic pressure-bearing hose to 24 mm and the wall thickness to 2 mm, the working water flow velocity calculated according to Bernoulli's equation is 35.18 m / s. Since the main body of the fracturing rod is in close contact with the fracturing hole wall and the pressure-bearing hose is a high-elastic hose, the elastic modulus of the rock mass is used as the elastic modulus of the pipeline material during calculation. The elastic modulus of the rock mass is generally 1 - 10×10 4 MPa, and in this calculation, 5×10 4 MPa = 5×10 10 Pa

[0044] Substituting the data, we get ΔP = 422.16 Bar = 42.2 MPa

[0045] The instantaneous pressure borne by the valve and the pipeline when the water hammer effect occurs is P 工作 +ΔP = 52.2 MPa

[0046] The commonly used hydraulic splitting rods on the market work under a hydraulic oil pressure of 1200T - 5000T. When converted to pressure, the working pressure of the 5000T hydraulic oil pressure is about 8 MPa. The pressure of the invention device is controllable during operation. Compared with the commonly used hydraulic splitting rods, it can generate high pressure instantly, achieving the effect of splitting rocks. It also does not require devices such as high-pressure pumping stations and has strong usability under complex working conditions.

Claims

1. An apparatus for multiple transient fracturing of rocks based on the water hammer effect, characterized in that: It comprises a high-pressure water supply system and a water hammer fracturing system connected thereto, wherein the water hammer fracturing system comprises a fracturing rod body, a cavity for accommodating a first high-pressure rigid tube is provided in the center of the fracturing rod body, four trapezoidal grooves are provided along the length direction of the outer periphery of the fracturing rod body, the angle between adjacent trapezoidal grooves is a right angle, a water outlet connected to the cavity is provided at the bottom of each trapezoidal groove, a fracturing assembly module matching its shape is provided in each trapezoidal groove, a high-pressure resistant and highly elastic hose accommodating cavity is provided at the bottom of each fracturing assembly module, a high-pressure resistant and highly elastic hose is provided in the accommodating cavity, one end of which is connected to the first high-pressure rigid tube through the water outlet, the outlet of the other end of the high-pressure resistant and highly elastic hose is connected to the self-locking valve body through the second high-pressure rigid tube, and the self-locking valve body comprises a barrel-shaped body, the top of the barrel body is provided with an opening, and the barrel body A circular floating barrel cover is provided inside, and the outer diameter of the barrel cover is larger than the inner diameter of the opening; the high-pressure water supply system includes a high-pressure resistant water tank, the top of the high-pressure resistant water tank is provided with an opening, and the inside of the high-pressure resistant water tank is provided with a plunger valve, the top of the plunger valve is connected to the second pressurizing surface through a connecting rod, the top of the second pressurizing surface is provided with a first pressurizing surface, the first pressurizing surface is fixedly connected to the outer wall of the high-pressure resistant water tank through a fixed rod, a hydraulic pump is provided between the first pressurizing surface and the second pressurizing surface, the water outlet at the bottom of the high-pressure resistant water tank is connected to the high-pressure resistant and high-elasticity hose inside the fracturing rod body through a first high-pressure hard pipe; a switch valve, a pressure relief valve and a one-way valve are provided on the first high-pressure hard pipe in sequence, a water inlet is also provided at the bottom of the high-pressure resistant water tank, and a pressure relief valve is also provided on the second high-pressure hard pipe; a buffer structure is provided in the accommodating cavity at the bottom of the fracturing assembly module.

2. The tunneling method of the device for fracturing rocks multiple times transiently based on the water hammer effect according to claim 1, characterized in that, The following steps are involved: S1. Arrange fracturing holes and fracturing auxiliary holes on the excavation face by drilling, and place the device in the fracturing hole; S2. Close the outlet valve of the high-pressure water tank, connect all components, and fill the high-pressure water tank with water; S3. Pressurize the water in the high-pressure water tank using a hydraulic pump between the first and second pressurizing surfaces until the pressure indicator reaches 10 MPa. Pressurization is stopped and the outlet valve is opened. Water flows through the elastic high-pressure hose and into the self-locking valve. When the self-locking valve closes, a high-intensity water hammer effect occurs within the elastic high-pressure hose. The hose instantly expands, generating high pressure between the assembly module and the fracturing hole wall, thereby crushing the rock mass. S4. Open the pressure relief valve, re-add the water in the self-locking valve to the high-pressure water tank for reuse, and repeat steps S2-S3 until an open surface is formed around the fracturing hole; S5. Repeat steps S2-S4 until all rocks around the pre-set fracturing holes are dug out, supported and sprayed to enter the next cycle.

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