JPS6144190B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a method for excavating (rock crushing) underwater objects such as submarine rock, submarine hard soil, and marine structures using a high-pressure water jet containing solid particles such as sand, gravel, clay, and coral reef debris. This article relates to excavation methods and equipment. The currently used mechanical methods for excavating seabed rocks include the weight type, large grab type, and
There is a pump dredger type cutter system. The common drawbacks of these methods are that the excavation work efficiency is extremely low due to intermittent excavation work, that construction is impossible on ultra-hard or highly undulating rock, and that the excavation impact is large and cannot be used in other port structures. In addition, since the weight, basket, and cutter are used as excavation means to come into contact with rock, etc., the excavation means and accessories are subject to severe wear and tear. In addition, there is the blasting method, which does not use machinery, but the biggest drawback of this method is that the impact is extremely large, which can affect fish and the nearby ground and structures above it. , which are currently rarely constructed due to fisheries compensation and other reasons. The present invention was made by conducting research in view of the drawbacks of conventional construction methods as described above, and developed an excavation method and excavation equipment that eliminate these drawbacks. To provide a method for excavating submarine rock, etc., which has various advantages, such as being able to deal with the undulations and hardness of the submarine rock by using high-pressure water jet as the drilling medium, and enabling efficient continuous excavation with little impact. exists in Next, the excavation method of the present invention will be explained in detail below based on the drawings. First, as shown in Figure 1, the high pressure water jet j
A movable nozzle N that injects and solid particles h with the solid particles h surrounding a high-pressure water jet j is placed in the sea s, and the solid particles h obtained by the nozzle N are
A high-pressure water jet j containing
By injecting a high-pressure water jet j containing
and a high-speed water layer S, and excavation of seabed rock R etc. is carried out by the synergistic effect of the impact force by the solid particles h ejected by fluid acceleration and the fluid force by the fluid part excluding the particles h. This is an excavation method.
Applications to which the excavation method of the present invention is applied include rock crushing, excavation, etc. of submarine rock, hard soil, and ordinary ground.
The drilling method of the present invention is particularly useful for rock crushing work on submarine tunnels or near offshore structures, as it has little impact. This method is also useful for drilling holes in concrete structures because the iron knots do not interfere with construction as in the construction method, and drilling can be performed with the iron knots left in place. In addition, the excavation medium used in the construction method of the present invention is
Solid particles h are transferred under pressure with a high-pressure water jet j pressurized by a pump and a fluid such as water or air.The high-pressure water jet j can use seawater, and the solid particles h can use sand and gravel existing on the seabed・It is possible to use viscosity, coral reef debris, etc. In this case, it is preferable because excavation work can be done at a low cost, but solid particles h
For this purpose, sand prepared in advance may be used. Next, to explain the excavation action by the construction method of the present invention, first, immediately after being sprayed from the nozzle N,
As shown in Fig. 2, the solid particles h surround the high-pressure water jet j, and then, as the high-pressure water jet j and the solid particles h move by injection in the sea s, as shown in Fig. 3, , a solid particle mixed layer H which is subjected to fluid acceleration in an encircling cylindrical shape around a high pressure water jet column J containing solid particles h, and a high speed water flow layer S by introducing surrounding seawater are formed. In other words, since the high-pressure water jet j and solid particles h are injected into the sea s, a high-speed water flow layer S is formed by the seawater, and the flow rate involved in excavation increases.
In addition, since the solid particles h are subjected to fluid acceleration by the high-pressure water jet column J from the inside and the high-speed water flow layer S from the outside, the impact force is increased, and moreover, the solid particles h are in a wide-range accelerated injection state dispersed around the outer periphery of the high-pressure water jet column J. This is extremely effective for excavating rock R. In this respect, if the excavation method of the present invention is applied to land rock, etc., there will be no increase in the flow rate involved in excavation, and only the parts of solid particles that come in contact with the high-pressure water jet will undergo fluid acceleration. In addition, when using a conventional drilling device for land rock, etc., which uses a nozzle that injects water jet to surround solid grains, it is difficult to achieve sufficient drilling effect. Since the solid particles are concentrated in the center, only spot perforations can be made, and these facts also confirm how useful the method of the present invention is in the sea. The excavation action that crushes the rock R etc. is caused by the impact force caused by the solid particles h ejected by fluid acceleration, the dynamic pressure mainly from the high pressure water jet J, and the jet flow that causes tensile fracture on the surface of the rock R etc. Due to the synergistic effect of the fluid force caused by negative pressure, as shown in Figure 1,
It is possible to perform excavation while scattering seabed rock R etc. outward as fragments R. How the impact force caused by the solid particles h is involved in this excavation action has been investigated in the excavation method using only a high-pressure water jet, which has been studied in the experimental stage.
It is not possible to excavate without jet injection using twice the water pressure, and if you are trying to excavate rock with high compressive strength, if you do it with a small flow rate and ultra-high pressure, it will be more like cutting than excavation, and you will not be able to do it with a large flow rate and ultra-high pressure. However, in contrast, in the method of the present invention, the compressive strength of the excavated body is increased by applying the impact force of solid particles h. As is clear from the experimental results, the excavation effect is sufficient for practical use. Here ^, to explain the experiment conducted by the present inventor, as shown in FIG. A nozzle N for injecting (sand) and high-pressure jet water is placed above the specimen 4. The mortar specimen 4 used was 200 mm in length, 250 mm in width, and 150 mm in height, and the solid particles h were pneumatically fed by compressor 5. / ^cm2 , flow rate
1451/min), 8 is a sand tank, 9 is a pressure reducing valve, and 10 is a valve. The experiment consisted of an experiment in which high-pressure jet water containing solid particles, which is the construction method of the present invention, was injected onto the mortar specimen 4, and an experiment in which only high-pressure jet water was injected into the mortar specimen 4.
The experiment was conducted for 60 seconds, and the results are shown in Table 1 below.

[Table] Based on the above results, the state of mortar specimen 4 after the experiment is as shown in Figure 11. When the construction method of the present invention was used, A had a hole in the center and had sufficient excavation effect. On the other hand, in the case of the method using only a high-pressure water jet without mixing sand, an unmeasurable degree of spalling was observed on the surface, and no excavation effect was achieved at all. . Considering the above experiments, when using the method of the present invention, the jet water pressure (6.58 Kg/cm ² ) is less than 1/3 of the compressive strength of mortar specimen 4 (21.18 Kg/cm ² ). The excavation effect was also confirmed in both cases, and when comparing the two, it is possible to confirm how much the inclusion of sand contributes to the excavation effect. In addition, we conducted an experiment in which the construction method of the present invention was applied to submarine rock using a rock crushing ship at sea.
(Results are omitted) In this experiment as well, good results were obtained that were sufficient for practical use. In addition to the method of the present invention, there may also be an excavation method in which solid particles are mixed into a fluid in advance and then injected into the seabed rock R, etc., and it is presumed that this method will also have the same effect as the present invention. Since the present invention is based on the excavation method as described above, it has the following effects. (1) Since it contains solid particles h, sufficient excavation effects can be achieved even at a much lower pressure level than the method using only high-pressure water jet j. (2) Since the crushing media is water and solid particles, there is less impact on the surroundings, allowing drilling work near offshore structures. (3) Continuous excavation is possible by moving the nozzle N, so excavation efficiency is high. (4) Because the crushing is non-contact with the rock R, etc., excavation can be carried out regardless of the undulations of the rock R, etc. (5) Pressure and flow rate of high-pressure water jet j and solid particles h
By selecting the mixing ratio of , any hard or soft body can be excavated. (6) Cheap excavation work is possible because seawater and sand existing on the seabed can be used. (7) Since the nozzle N only needs to be moved to follow the bedrock R, etc., excavation work can be carried out even at a distance, in a narrow place, or even in the shadows, as long as the hose is extended. (8) By increasing the number of nozzles N, it is possible to carry out multiple works at the same time, thereby improving excavation efficiency. (9) Since the solid particles are injected into the seawater surrounding the high-pressure water jet, a high-speed water flow layer S of seawater is formed on the outer periphery, and the flow rate involved in excavation increases, and the solid particles h are The high-pressure water jet column J receives fluid acceleration from the outside by the high-speed water flow layer S, so the impact force increases, and these solid particles are accelerated and injected in a dispersed state around the outer periphery of the high-pressure water jet column J. , submarine bedrock R, etc. can be excavated more effectively. Next, the excavation apparatus of the present invention will be described in detail below with reference to FIGS. 4 to 9. First, the gist of the device of the present invention is such that solid particles from the solid particle injection nozzle 2 are injected onto the outer periphery of the nozzle 1 connected to the high-pressure fluid supply source in a state surrounding the high-pressure water jet flowing out from the water jet nozzle 1. The opening ends of both nozzles 1 and 2 are arranged in relation to each other so that the nozzles 1 and 2 are movable relative to the underwater body to be excavated such as the seabed rock R. Here, to explain the relationship between the water jet nozzle 1 and the solid particle injection nozzle 2, what is shown in FIGS. 4 to 7 shows examples of the related arrangement of the water jet nozzle 1 and the solid particle injection nozzle 2. The nozzles shown in FIGS. 4 and 5 are equipped with a water jet nozzle 1 at the center of a solid particle injection nozzle 2, and both nozzles 1 and 2 are coaxially connected to the open end of the water jet nozzle 1 and the solid particle injection nozzle. The opening end of the solid particle injection nozzle 2 is arranged with a gap of 1 between the nozzle 2 and the opening end of the water jet nozzle 1.
By forming the diameter slightly larger than the opening end diameter of the
The solid particles are sprayed from the nozzle 2 while surrounding the high-pressure water jet flowing out from the water jet nozzle 1. The amount of solid particles supplied can be adjusted using water jet nozzle 1.
This can be done by adjusting the gap 1 between the opening end of the solid particle injection nozzle 2 and the opening end of the solid particle injection nozzle 2. The gap 1 between the opening ends of both nozzles 1 and 2 is preferably adjusted so that the solid particle supply rate is about 5%. Next, the nozzle shown in FIGS. 6 and 7 is a solid particle injection nozzle 2 with a plurality of tubular nozzles, and the nozzle 2 is placed in front of the water jet nozzle 1,
The opening end of the nozzle 2 is directed toward the high-pressure water jet flowing out from the water jet nozzle 1, so that the solid particles flowing out from the nozzle 2 surround the high-pressure water jet and are sprayed. The high-pressure fluid supply source includes a seawater tank 11, a high-pressure pump 12, and a supply hose 13, and a seawater supply pipe 14 is connected to the seawater tank 11. The solid particle supply source consists of a solid particle tank 15, a supply pump 16, and a supply hose 17, and when collecting sand or the like from the seabed, a solid particle supply pipe 18 is connected to the tank 15. In addition, the movable configuration of the water jet nozzle 1 and the solid particle injection nozzle 2 is such that both nozzles 1 and 2 are mounted on a nozzle holding device having a nozzle moving mechanism (based on a hydraulic cylinder, etc.), and the device and the drilling ship are movable over a movable length. An example of this is a configuration in which the nozzles 1 and 2 are connected by arms, but any configuration may be used as long as both nozzles 1 and 2 follow and move relative to the object to be excavated, such as the seabed rock R. Next, an example of a drilling ship equipped with the drilling equipment of the present invention will be explained using a conceptual diagram illustrating an example. The drilling ship shown in FIG. One seawater tank 11 is provided with a seawater inlet 20 and a suction pump 21, the other sand tank 15 is provided with a seasand suction pipe 22 and a suction pump 23, and the water jet nozzle 1 and the seawater tank are provided with a seawater suction pipe 22 and a suction pump 23. 11 is connected with a supply hose 13 via a high pressure pump 12 and a booster pump 24, and the solid particle injection nozzle 2 and sand tank 15 are connected with a supply hose 17 via a supply pump 16. It is movably provided on the nozzle holding plate 25, and the plate 25 and the hull 19 are connected by a movable long arm 26. This is a preferable example in that seawater and sea sand can be used. The drilling ship shown in FIG. 9 is of a type that stores solid particles such as sand, and the branch seawater supply pipe 2 from the booster pump 24
7 is placed in the sand tank 15. Although the excavation device of the present invention has been described above, its nozzle configuration and movable configuration are not limited to the illustrated configuration. In the figure, j indicates a high-pressure water jet, h indicates solid particles, R indicates submarine rock, h indicates sea sand, and r indicates debris. Further, when using the device of the present invention, the application location and operation are as described in the above-mentioned construction method. Since the present invention is an excavation device as described above, it has the following effects. (1) Since it is a non-contact crushing device that uses water jet and solid particles as the drilling medium, there is no wear and tear on the excavation means as with conventional devices. (2) Since the reaction force applied to the nozzles 1 and 2 is small, the structural rigidity of the excavated portion may be small. (3) It can be made into an efficient continuous excavation device by following the movement to the bedrock R etc. (4) Since it is a non-contact crushing device for rock R, etc., it can cope with the undulations of rock R, etc. (5) It can be a device that uses seawater and sand existing on the seabed. (6) By increasing the number of nozzles 1, 2 and supply hoses 13, 17, it is possible to create an excavation device that can be used in large numbers at the same time. (7) The solid particle injection nozzle 2 is provided on the outer periphery of the water jet nozzle 1 so that the solid particles surround the high-pressure water jet and are injected into the seawater, so that a high-speed water flow layer S of seawater is formed on the outer periphery. As the flow rate involved in excavation increases, the solid particles h are formed from the inside by the high-pressure water jet column J,
Since the fluid is accelerated from the outside by the high-speed water layer S, the impact force increases, and these solid particles are accelerated and injected in a dispersed state around the outer periphery of the high-pressure water jet column J, which effectively destroys the seabed rock R, etc. can be excavated.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the excavation method of the present invention, Figure 2
The figure is a cross-sectional view taken along line A-A in Figure 1, and Figure 3 is a cross-sectional view taken along line A-A in Figure 1.
4 is a sectional view showing an embodiment of the drilling equipment of the present invention; FIGS. 5 to 7 are sectional views showing embodiments of the same equipment; FIGS. The figure is a conceptual diagram of a drilling ship equipped with the same device, FIG. 10 is a preliminary experiment device for the construction method of the present invention using the same device, and FIG. 11 is a perspective view showing a mortar specimen after the same experiment. j...High pressure water jet, h...Solid particles, N...
Nozzle, s...Undersea, R...Seafloor rock, J...High pressure water jet column, H...Solid particle mixed layer, S...High speed water flow layer, 1...Water jet nozzle, 2...Solid particle injection nozzle.

Claims (1)

[Claims] 1. A movable nozzle N that injects a high-pressure water jet j and solid particles h in a state in which the solid particles h surround the high-pressure water jet j is disposed in the sea s, and A high-pressure water jet j containing solid particles h is injected onto an underwater excavated body such as a submarine bedrock R, and the injection creates a solid particle-mixed layer H and a high-speed water flow layer S in a cylindrical shape surrounding the high-pressure water jet column J. A method for excavating seabed rocks, etc., characterized by excavating seabed rocks R, etc. by the synergistic effect of the impact force caused by the solid particles h formed and jetted by fluid acceleration and the fluid force caused by the fluid portion excluding the solid particles h. . 2 Water jet nozzle 1 connected to high pressure fluid supply source
A solid particle injection nozzle 2 connected to a solid particle supply source is provided on the outer periphery of the solid particle supply source, and both nozzles 1, 2
A drilling device for excavating submarine rock or the like, characterized in that the opening ends of the nozzles 1 and 2 are arranged in relation to each other, and the nozzles 1 and 2 are configured to be movable relative to an underwater object to be excavated, such as submarine rock R.