Method and apparatus for rock reinforcement

Abstract

A method and an apparatus for rock reinforcement are described. The method comprises the steps: to inject a first component and a second component through a first channel and a second channel respectively into a rock hole, wherein the first component and the second component are adapted for rock reinforcement and to inject a blocking agent through a third channel into at least said second channel, wherein said blocking agent provides a barrier in at least said second channel.

Claims

1. Method at rock reinforcement comprising the steps: a) to inject a first component and a second component through a first channel and a second channel respectively into a rock hole wherein the first component and the second component are adapted for rock reinforcement, characterized in that method comprises the step: b) to inject a blocking agent through a third channel into at least said second channel, wherein said blocking agent provides a barrier in at least said second channel.

2. Method according to claim 1, wherein the method comprises the step: c) to provide said rock hole before said step a) is performed.

3. Method according to claim 1, wherein the method comprises the step: d) to place a rock bolt adapted for rock reinforcement in said rock hole.

4. Method according to claim 3, wherein said first component and said second component are injected through said rock bolt.

5. Method according to claim 3, wherein said rock bolt is a self-drilling bolt.

6. Method according to claim 1, wherein said step a) comprises injecting said first component and said the second component at least partly simultaneously into said rock hole.

7. Method according to claim 1, wherein the method comprises the step: e) to inject a flushing agent into at least said first channel, wherein said blocking agent is adapted to prevent said flushing agent from coming into contact with said second component at said injection of said flushing agent.

8. Method according to claim 7, wherein said step b) is performed after said step a) and/or wherein said step e) is performed after said step b).

9. Method according to claim 1, wherein said first component is a hardener and said second component is a resin.

10. Apparatus for rock reinforcement comprising: a first channel adapted for injection of first component into a rock hole, a second channel adapted for injection of second component into said rock hole, wherein said first component and said second component are adapted for rock reinforcement and a mixer in connection with the first channel and the second channel for mixing the first component and the second component before the mixture is injected into the rock hole, a third channel directly connected to the second channel for injection of a blocking agent into at least said second channel, wherein when injected into at least said second channel the blocking agent provides a barrier in at least said second channel, wherein said third channel is also in connection with the mixer through said second channel.

11. Apparatus according to claim 10, wherein the third channel contains said blocking agent.

12. Apparatus according to claim 10 wherein the apparatus comprises a fourth channel for injecting of the blocking agent into the first channel, wherein said blocking agent provides a barrier in at least said first channel.

13. Apparatus according to claim 10 wherein the third channel is connected to a third channel nozzle, which third channel nozzle is adapted to receive a third hose for supplying of the blocking agent into the apparatus.

14. Apparatus according to claim 10 wherein at least said second channel comprises a valve-piston arranged to be positioned in at least a first position and a second position, wherein said valve-piston, in said first position, is arranged to permit injection of said second component into said rock hole, and wherein said valve-piston, in said second position, is arranged to prevent injection of said second component into said rock hole and to permit injection of said blocking agent into at least said second channel, wherein said valve-piston comprises a slot arranged so that, in said second position of the valve-piston, injection of said blocking agent is permitted into a third sub-channel of said second channel, and wherein, in said second position of the valve-piston, an inlet of the third sub-channel is blocked for the second component, preventing injection of the second component into the third sub-channel.

15. Apparatus according to claim 10, wherein said first channel is arranged to receive a flushing agent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The further aspects of the subject matter, including their particular features and advantages, will be readily understood from the following detailed description of one or several embodiments provided with reference to the accompanying drawings, where:

(2) FIG. 1 is a side-view of an exemplified apparatus at rock reinforcement at a rock hole with a rock bolt, shown in cross-section,

(3) FIG. 2 is a flow-chart showing a method at rock reinforcement,

(4) FIG. 3 is a perspective-view of the apparatus according to FIG. 1 and

(5) FIG. 4 is another perspective-view of the apparatus according to FIG. 1 and FIG. 3.

DETAILED DESCRIPTION

(6) The embodiments herein will now be described in more detail with reference to the accompanying drawings, in which example embodiments are shown. Disclosed features of example embodiments may be combined. Like numbers refer to like elements throughout.

(7) FIG. 1 illustrates an exemplified embodiment of an apparatus 1 at rock reinforcement or sometimes called rock-bolting. The apparatus 1 has been connected to a rock bolt 11 through a mixer 2 and a connection means 4. FIG. 1 illustrates as well a cross section through a rock hole 9 in a mountain where the rock bolt 11 has been placed in the rock hole 9.

(8) When a rock need to be reinforced, the rock hole 9 is drilled in the rock. This is made by using of a drill or by using a self-drilling bolt. The rock bolt 9 in FIG. 1 illustrates a self-drilling bolt comprising a drilling bit 30. A self-drilling bolt is placed in the rock hole while and simultaneously the rock hole is created by the self-drilling bolt. Self-drilling bolts are known in the art and therefor are not described herein in details.

(9) To anchor the rock bolt 11 in the rock hole 9 and to achieve rock reinforcement, a molding agent as for example a mixture of components, is injected in the rock hole. The mixture of components is injected by the apparatus 1. The mixture of components is solidifying or hardening inside the rock hole and around the rock bolt 11 and in this way the rock bolt 11 is anchored or is fastened inside the rock hole. As a result of this the rock at and around the rock hole 9 is reinforced. According to the embodiment illustrated in FIG. 1, the rock bolt 11 is hollow, which permits the mixture of components may be injected through the rock bolt 11 and out through the drilling bit 30 into the rock hole 9.

(10) FIG. 2 shows an exemplified method 100 at rock reinforcement. The method 100 may for example be implemented by a control unit (not shown).

(11) The method 100 comprises: to inject 101 a first component and a second component through a first channel and a second channel respectively into a rock hole, wherein the first component and the second component are adapted for rock reinforcement. The step to inject 101 the first component and the second component through the first channel and the second channel respectively into a rock hole may comprise to inject the first component and the second component at least partly simultaneously into the rock hole.

(12) Further the method 100 comprises to inject 103 a blocking agent through a third channel into at least the second channel, wherein the blocking agent provides a barrier in at least the second channel.

(13) The method 100 may also comprise to inject 103 a flushing agent into at least the first channel.

(14) Further, the step to inject 103 the blocking agent through the third channel into at least the second channel may be performed after the step to inject 101 the first component and the second component through the first channel and the second channel respectively into a rock hole and/or wherein the step to inject 103 the flushing agent into at least the first channel may be performed after the step to inject 105 the blocking agent through the third channel into at least the second channel.

(15) The method 100 may also comprise the step to inject the blocking agent into the first channel.

(16) According to some embodiments, the method 100 may comprise to provide 107, for example to drill, the rock hole before the step to inject 101 the first component and the second component through the first channel and the second channel respectively into the rock hole is performed. The method 100 may further comprise to place 109 the rock bolt, adapted for rock reinforcement, in the rock hole.

(17) FIG. 3 illustrates the apparatus 1 in FIG. 1. The apparatus 1 comprises a first channel 3 adapted for injection of first component A into a rock hole, and a second channel 5 adapted for injection of second component B into the rock hole. Thus, in this example, the earlier mentioned mixture of components comprises of the first and the second components A, B. According to the embodiment illustrated in FIG. 3, the second channel 5 comprises three sub-channels named a first sub-channel 5.1, a second sub-channel 5.2 and a third sub-channel 5.3. The first sub-channel 5.1 in FIG. 3 is arranged substantially radially, i.e. substantially perpendicular in relation to an axis X through the apparatus 1. The second sub-channel 5.2 is arranged substantially along the axis X and substantially in the middle of the apparatus 1. The third sub-channel 5.3 extends along a direction substantially perpendicular in relation to the axis X and substantially perpendicular in relation to the first sub-channel 5.1. The first sub-channel 5.1 extends also from a second channel nozzle 6 arranged at a periphery of the apparatus 1 towards the second sub-channel 5.2 arranged substantially in the middle of the apparatus 1 and the third sub-channel 5.3 extends from the second sub-channel 5.2 and ends through a second opening 8 of an outlet nozzle 10.

(18) The directions towards and from refer here directions in relation to injection direction R2 of the second component B at the inlet to the second channel nozzle 6 and in relation to the axis X. The second channel nozzle 6 is arranged to receive a second hose (not shown) for supplying of the second component B into the apparatus 1. The tree sub-channels 5.1, 5.2 and 5.3 are interconnected with each other and together form the second channel 5.

(19) The first channel 3 (not shown in details in FIG. 3) may be arranged in a similar manner as the second channel 5. Thereby, the first component A may be injected, for example in the injection direction R1 of the first component A, through a first channel nozzle 12 into the apparatus 1 and further out through a first opening 14 of the outlet nozzle 10.

(20) The first channel nozzle 12 is arranged to receive a first hose (not shown) for supplying of the first component A to the apparatus 1. In the similar way as the second component B above refer directions in and out directions in relation to the injection direction R1 of the first component A at the inlet to the first channel nozzle 12.

(21) The first channel 3 and the second channel 5 are separated from each other that the first component A and the second component B do not come in contact with each other inside the apparatus 1. The first channel 3 and the second channel 5 may be achieved by for example molding of the apparatus 1 in a form. The form is then designed so that two separate channels are obtained inside the apparatus 1 after a molding process. The first channel 3 and the second channel 5 may also be achieved by processing as for example drilling, milling or similar.

(22) The outlet nozzle 10 may be arranged to receive a mixer (not shown in FIG. 3) adapted to mix the first component A and the second component B with each other.

(23) The first component A and the second component B are adapted for rock reinforcement, i.e. they are developed for example this purpose. The first component A may contain a hardener as for example sodium silicate, an alcohol, a polyol or similar or a combination thereof. The second component B may contain a resin as for example methylene diphenyl isocyanate (MDI) or similar. The first component A and the second component B are intended to be mixed with each other at injection of the first component and the second component A, B into the rock hole. Mixing of the first component A and the second component B may preferably be done in a mixer (not shown). The mixer may then be connected to the outlet nozzle 10. When the components A, B are mixed a reaction in the resin starts that is trigged by the hardener and that results in that crosslinks in the resin are created. Said mixture of the first component A and the second component B may be guided, or brought, further from the mixer into the rock hole where the mixture is and thereby a rock bolt is anchored inside the rock hole to reinforce the rock around the rock hole.

(24) As illustrated in FIG. 3, the first channel 3 may be arranged to receive a flushing agent W, for example in a direction R3 of the flushing agent. This, through a flushing nozzle 16. According to the embodiment illustrated in FIG. 3, the first channel nozzle 12 and the flushing nozzle 16 are arranged at a T-connection 18 connected to the first channel 3. The flushing nozzle 16 is arranged to receive a flushing hose (not shown) for supplying of the flushing agent W into the apparatus 1. The T-connection 18 comprises a valve (not shown) for controlling the flows of the first component A and of the flushing agent W into the first channel 3. The valve is arranged so that when injecting the first component A inflow of the flushing agent W into the first channel 3 is prevented and is arranged so that when injecting of the flushing agent W the inflow of the first component A into the first channel 3 is prevented.

(25) The flushing agent W may be water, oil or similar.

(26) The apparatus 1 comprises also a third channel 7 for injecting of a blocking agent S into at least the second channel 5. According to the embodiment illustrated in FIG. 3, the third channel 7 is arranged substantially parallel with the second channel 5 and is direct connected to the second sub-channel 5.2 of the second channel 5. The third channel 7 is connected to a third channel nozzle 20, which third channel nozzle 20 is adapted to receive a third hose (not shown) for supplying, for example in an blocking agent S injection direction R4, of the blocking agent S into the apparatus 1.

(27) The apparatus 1 may comprise a fourth channel (not shown) for injecting of the blocking agent S into the first channel 3. The fourth channel may be arranged in a similar way as the third channel 7 described above.

(28) The blocking agent S is an agent with chemical characteristics that make that the blocking agent S does not mix with any of the first component A, the second component B or with the flushing agent W. Further, the blocking agent may have protecting characteristics against wear inside the apparatus 1. The blocking agent S may be fat and viscous agent as for example fat, silicone or similar.

(29) According to the embodiment illustrated in FIG. 3, the second channel 5 comprises a valve-piston 13 movable arranged in the second channel 5 so that the valve-piston 13 may be positioned in a first position p1 and a second position p2. The valve piston 13 may form a part of a needle valve. Thus, the needle valve comprises the valve-piston 13, for example in a form of a needle, piston or similar. The needle valve may be biased in the second position by a spring 22 in a known manner. Also other types of valves than needle valve may be used in the apparatus 1. For example, a ball valve, cone valve or similar may be used. The needle valve or if other type of valve, may be controlled hydraulically or electrically.

(30) The valve-piston 13 in FIG. 3 is illustrated in the first position p1. In the first position p1, the valve-piston 13 is arranged to permit injection of the second component B into the rock hole. When the second component B is pumped into the apparatus 1 through the second channel nozzle 6 and by a pump (not shown) a pressure in the second channel is created that cause the valve-piston 13 to move to the first position p1. The spring 22 is adapted to act on the valve-piston 13 with a spring force that is less than a pressure force acting on the valve-piston 13 by the pressure in the second channel 5 caused by the second component B when the second component B is injected into the second channel 5. As illustrated in FIG. 3, in the first position of the valve-piston 13, the inlet to the third sub-channel 5.3 is open so that the second component B may flow into the third sub-channel 5.3 and further out through the second opening 8.

(31) According to the embodiment illustrated in FIG. 3, the valve-piston 13 is arranged to permit injection of the blocking agent S into the second channel 5 when the valve-piston 13 is in the first position p1. However, a control unit (not shown) is connected to the apparatus 1 and is arranged to stop supply of the blocking agent S into the second channel 5 in the first position p1 of the valve-piston 13.

(32) FIG. 4 illustrates the apparatus 1 in FIG. 3. In FIG. 4, the valve-piston 13 is shown in the second position p2. In the second position p2, the valve-piston 13 is arranged to prevent injection of the second component B into the rock hole and to permit injection of the blocking agent S into at least the second channel 5. When earlier mentioned pump (not shown) for pumping of the second component B stops to work, the pressure in the second channel 5 decreases. This permits that the spring force of the spring 22 can overcome the inertia of the second component B in the second channel 5 and to move the valve-piston 13 to the second position p2. As illustrated in FIG. 4, the valve-piston 13 has been moved to the second position p2 by the spring 22, thereby has revert to its biased position. The valve-piston 13 comprises a surface 24 adapted to join tight in contact with an edge surface 26 of the second sub-channel 5.2 at the inlet to the third sub-channel 5.3 and at the transition area between the second sub-channel 5.2 and the third sub-channel 5.3 in the second position p2 of the valve-piston 13. In the second position p2 the spring 22 may act on the valve-piston 13 with a spring force that permits a tight connection between the surface 24 and the edge surface 26. Thereby, the inlet to the third sun-channel 5.3 may be blocked for the second component B in the second position p2 of the valve-piston 13, which may prevent injection of the second component B into the third sub-channel 5.3.

(33) When the valve-piston 13 is in the second position p2, injection of the blocking agent S into at least the second channel 5 is permitted. As illustrated in FIG. 4, the valve-piston 13 may comprise a channel 28 arranged around the valve-piston 13, for example in its surface along a cross section of the valve-piston 13. In the second position p2, the channel 28 is arranged to create a connection channel between the third channel 7 and the third sub-channel 5.3 of the second channel 5. Thereby, injection of the blocking agent S into the third sub-channel 5.3 is permitted. When the blocking agent S is injected into the third sub-channel 5.3, the second component B is extruded from the third sub-channel 5.3 through the second opening 8. Thereby, the sub-channel 5.3 is filled with the blocking agent S, which protects the sub-channel 5.3 from other substances to flow into the sub-channel 5.3.

(34) The third channel 7 may be arranged so that the third channel 7 is connected directly to the third sub-channel 5.3. According to such embodiment, the valve 13 may be arranged without a channel.

(35) As described, above the apparatus 1 may comprise the fourth channel (not shown) for injecting of the blocking agent S into the first channel. The fourth channel may be connected to the first channel in similar way arranged in a similar way as the third channel 7 is connected to the second channel 5 as above.

(36) Thus, in the second position p2, the flushing agent W may be injected into the rock hole without risks that the flushing agent W comes in contact with the second component B inside the second channel 5 of the apparatus 1. Consequently, with advantage crystallization of the second component B in at least the second channel 5 is prevented, which otherwise occurs when the flushing agent S comes in contact with the second component B. Thereby, the risk that at least the second channel will be blocked, i.e. will be filled with crystals of the second component is decreased. As a result thereof the risk for interruptions during work with rock reinforcement is reduced, i.e. reliability at rock reinforcement is improved.