JP2012021275A - Soil improvement method and monitor mechanism used in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil improvement method capable of effectively preventing occurrence of turbulent flow even when the discharge amount and discharge pressure of an ultrahigh pressure hardening material increase and substantially prolonging the jetting distance of the ultrahigh pressure hardening material, and a monitor mechanism used in the same.SOLUTION: An ultrahigh pressure liquid path 11 formed from an entrance 9 of a monitor mechanism 1 to a hardening material jetting nozzle N includes an entrance side path 12, a jetting nozzle side path 13, and first and second intermediate paths 14 and 15 positioned between both. In the view from a flowing direction upstream side, an angle α1 at which the axis of the entrance side path 12 is bent to the axis of a jetting pipe rod 2, an angle α2 at which the axis of the first intermediate path 14 is bent to the axis of the entrance side path 12, an angle α3 at which the axis of the second intermediate path 15 is bent to the axis of the first intermediate path 14, and an angle α4 at which the axis of the jetting nozzle side path 13 is bent to the axis of the second intermediate path 15 are set within 50°, respectively.

Description

  The present invention relates to a ground improvement method for performing ground cutting with a super-high pressure jet liquid using a swirling jet, and a monitor mechanism used therefor.

  Conventionally, as a ground improvement method for cutting the ground with an ultrahigh pressure jet liquid, an ultrahigh pressure jet method is known. This ultra high pressure injection method includes single pipe type super high pressure injection method such as CCP method, double pipe type super high pressure injection method such as jet grouting method (JSG method), column jet grouting method (CJG method) and rosin jet pile. There are triple pipe type ultra-high pressure injection methods such as the construction method (RJP method).

In this ground improvement method of cutting the ground with this type of super high pressure jet liquid, the super high pressure jet liquid (cement milk) is supplied from the hardener injection nozzle of the monitor mechanism provided under the injection pipe rod inserted to the target depth in the ground. By cutting the ground with ultra-high-pressure jet liquid and mixing and stirring the soil particles and the hardener by swirling jets. A pile-like solidified body (improved body) is created. The ground cutting / stirring mechanism by the super-high pressure jet liquid is based on the effective action of dynamic pressure action, impact force, pulsation load, cavitation phenomenon, wedge effect, polishing effect and the like.
Normally, as shown in FIG. 11, the curing material injection nozzle 31 for injecting the ultrahigh pressure jet liquid of the monitor mechanism 30 into the ground is provided at a right angle from the ultrahigh pressure liquid passage 32 (see, for example, Patent Document 1). .)

In recent ground improvement, the development of ultra-high pressure pumps has progressed, and the discharge volume and discharge pressure of ultra-high pressure jet liquid has become possible. As a result, pile-like solidified bodies (improved bodies) created in the ground ) To increase the formation diameter. By increasing the discharge volume and discharge pressure, increasing the discharge diameter and discharge pressure, increasing the injection pipe rod as a double pipe and triple pipe, increasing the number of curing material injection nozzles, and increasing the number of ultrahigh pressure pumps, We are trying to realize expansion.
Thus, in order to increase the diameter of the formed diameter, it has been required to supply a large amount of ultrahigh pressure hardened material such as cement milk that is pumped through the inside of the injection tube rod.

Japanese Patent Laid-Open No. 6-306846

  However, when a large amount of such ultra-high-pressure hardened material is fed, the increase in the flow rate is unavoidable due to the limitations and limitations of the injection tube rod diameter and the monitor mechanism diameter. 11 is formed in the injection tube rod or the monitor mechanism, the turbulent flow inevitably occurs in the right-angled portion of the ultrahigh pressure liquid passage 32 and the hardener injection nozzle 31 as shown in FIG. This causes a loss of energy, and there has been a limit to making progress in increasing the diameter of the product. In addition, due to the increase in the discharge amount and discharge pressure of the ultra-high pressure hardened material accompanying the increase in the diameter of the formed diameter, the monitor mechanism is severely worn, leading to an increase in the consumption cost.

  Therefore, the present invention has been made to solve the above-described problems, and the object of the present invention is to insert the injection tube rod as described above to a target depth in the ground, and The hardener is pressed in from the hardener inlet of the swivel attached to the upper part of the rod at ultra high pressure, and the hardener is continuously injected in the pipe radial direction from the hardener injection nozzle of the monitor mechanism assembled to the lower part of the injection pipe rod. In the ground improvement method in which the injection tube rod is driven to rotate and the surrounding ground is cut and stirred by the high pressure jet of the hardened material, it is formed between the entrance of the monitor mechanism and the hardened material injection nozzle. By devising the configuration of the ultra-high pressure liquid passage, the generation of turbulent flow can be prevented even if the discharge amount and discharge pressure of the ultra-high pressure hardened material increase with the increase in the diameter of the formed diameter. Worn out Small to provide a monitoring mechanism for use therewith and ground improvement method to obtain aim to improve the durability.

  In the case where a corner portion is present in the ultra high pressure liquid passage from the entrance of the monitoring mechanism to the curing material injection nozzle, the inventor makes all the bending angles when the ultra high pressure curing material is bent at the corner portion within 50 °. It was found that the generation of turbulent flow in the ultra-high pressure liquid passage can be prevented by setting to. And it discovered that the injection distance of an ultra-high pressure hardening material could be increased dramatically by preventing the generation of turbulent flow and rectifying the flow. The present invention has been made based on such knowledge.

  According to the ground improvement method of the present invention, as described in claim 1, the injection tube rod is inserted to a target depth in the ground, and the hardening material is applied to the ultra high pressure from the hardening material inlet of the swivel attached to the upper portion of the injection tube rod. The super high pressure hardened material is continuously injected in the radial direction of the tube from the hard material injection nozzle of the monitor mechanism assembled with the lower part of the injection tube rod, and the injection tube rod is swiveled to drive the ultra high pressure. In the ground improvement method in which the surrounding ground is cut and agitated by a high pressure jet of hardened material, the corner portion in the ultrahigh pressure liquid passage from the inlet for receiving the ultrahigh pressure hardened material to the hardener jet nozzle of the monitor mechanism All the corners are set within 50 °.

  The monitoring mechanism used in the ground improvement method is assembled at the tip of the injection tube rod as described in claim 2, and receives an ultrahigh-pressure hardener, a hardener injection nozzle, and the hardening from the inlet. And an ultrahigh pressure liquid passage formed between the material injection nozzles, and all the corners of the ultrahigh pressure liquid passage are set to be within 50 °.

  In the monitor mechanism according to claim 2, as described in claim 3, it is preferable that the inner surface of the ultrahigh pressure liquid passage is formed of cemented carbide.

  According to the first and second aspects of the present invention, all the bending angles of the corner portions in the ultra-high pressure liquid passage from the inlet for receiving the ultra-high pressure curing material of the monitor mechanism to the curing material injection nozzle are within 50 °. Therefore, it is possible to prevent the occurrence of turbulent flow even when the discharge amount and discharge pressure of the ultra-high pressure curing material increase in the ultra-high pressure liquid passage, and the ultra-high pressure liquid smoothly enters the curing material injection nozzle. Therefore, the jet cross-section of the injected ultra-high-pressure jet can be made circular, and the size of the circular cross-section can be reduced, thereby making it possible to dramatically increase the flying distance of the super-high-pressure jet liquid and It can make a big leap forward.

  According to the third aspect of the present invention, it is possible to reduce wear and improve durability of the monitor mechanism.

It is a longitudinal cross-sectional view which shows one Example of the monitor mechanism of this invention. It is an external view of the swivel attached to the head of the injection pipe rod used for the ground improvement construction method of the present invention. It is explanatory drawing which shows the construction procedure of the ground improvement construction method of one Example of this invention. It is sectional drawing which shows one Example of the solidified body (improved body) created by the ground improvement construction method of this invention. It is sectional drawing which shows the other Example of the solidified body (improved body) created by the ground improvement construction method of this invention. It is sectional drawing which shows the further another Example of the solidified body (improved body) created by the ground improvement construction method of this invention. It is a longitudinal cross-sectional view of the monitor mechanism of another Example. It is an external view of the swivel attached to the head of the injection tube rod of the monitor mechanism of FIG. It is a longitudinal cross-sectional view of the monitor mechanism of other Example. FIG. 10 is a cross-sectional view of the monitor mechanism of FIG. 9. It is a longitudinal cross-sectional view which shows the connection part of the ultrahigh pressure liquid channel | path and the hardening | curing material injection nozzle in the monitor mechanism of a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, the monitor mechanism 1 used for the ground improvement method of the present invention is a pile-like solidified body (improved body, the same applies hereinafter) by a ground improvement method such as a single-tube super-high pressure injection method such as a CCP method. ) Is attached to the distal end portion of the single-tube injection tube rod 2 used when forming the first tube) via the coupling 3. A single tube swivel 5 shown in FIG. 2 is attached to the head of the injection tube rod 2.

  As shown in FIG. 2, the swivel 5 is opened in a part of the upper peripheral surface thereof, and extends from the ultra-high pressure pump (not shown) to an ultra-high pressure hardening material inlet 6 and from the inlet 6 to the center. Furthermore, a passage 7 communicating with the lower end surface along the axis is provided. A hook portion 8 for suspending the injection tube rod 2 with a crane or the like is integrally provided on the head of the swivel 5.

  As shown in FIG. 1, the monitor mechanism 1 includes an inlet 9 for receiving an ultrahigh-pressure curing material from an ultrahigh-pressure curing material passage 4 in an injection tube rod 2 communicating with the lower end of a passage 7 of a swivel 5, and an ultrahigh-pressure curing material. It consists of a single tube structure having a single hardener injection nozzle N that continuously injects in the radial direction of the tube, and an ultrahigh-pressure liquid passage 11 that is formed in communication between the inlet 9 and the hardener injection nozzle N. The ultra high pressure liquid passage 11 includes an inlet side passage 12 that is continuously located on the inlet 9 side, an injection nozzle side passage 13 that is continuously located on the hardener injection nozzle N side, an inlet side passage 12 and an injection nozzle side passage. 13 is provided with at least one intermediate passage located in succession between the first and second intermediate passages 14 and 15 in the illustrated example.

  When the corner portion is present in the ultrahigh pressure liquid passage 11 from the inlet 9 of the monitor mechanism 1 to the curing material injection nozzle N, the inventor has a bending angle when the ultrahigh pressure curing material is bent at the corner portion. It has been found that when the amount exceeds 50 °, the flow state in the ultrahigh pressure liquid passage 11 becomes turbulent when the discharge amount and discharge pressure of the ultrahigh pressure liquid (curing material) increase in the ultrahigh pressure liquid passage 11. Therefore, the generation of such turbulent flow can be prevented, the ultrahigh pressure liquid smoothly enters the curing material injection nozzle N, and the jet section of the jetted ultrahigh pressure jet is made circular and the size of the circular section is reduced. The corner of the corner portion existing in the ultrahigh pressure liquid passage 11 from the inlet 9 of the monitor mechanism 1 to the hardener injection nozzle N so that the flying distance of the superhigh pressure jet liquid can be dramatically increased. α1 to α4 are all set within 50 °.

  Specifically, the angle α1 at which the axis of the inlet side passage 12 bends with respect to the axis of the injection tube rod 2 when viewed from the upstream side in the flow direction, and the first axis with respect to the axis of the inlet side passage 12 when viewed from the upstream side in the flow direction. The angle α2 at which the axis of the first intermediate passage 14 bends, the angle α3 at which the axis of the second intermediate passage 15 bends with respect to the axis of the first intermediate passage 14 when viewed from the upstream side in the flow direction, and the upstream side in the flow direction The angles α4 at which the axis of the injection nozzle side passage 13 bends with respect to the axis of the second intermediate passage 15 when viewed from above are all set within 50 °.

  As specific numerical values of α1 to α4, for example, all of α1 to α4 may be set to 45 °, α1 to α3 may be set to 50 °, and only α4 may be set to 40 °.

  With such a configuration, generation of turbulent flow can be effectively prevented, and the flight distance of the super-high pressure jet liquid can be greatly increased.

  Further, in the present embodiment, when viewed from the upstream side in the flow direction, the inlet side so that the axis of the inlet side passage 12 is bent to the opposite side of the axis of the injection tube rod 2 from the side where the hardener injection nozzle N is located. A passage 12 is provided, from which a first intermediate passage 14 extends downward (substantially directly below), and further through a second intermediate passage 15 that is shorter than the first intermediate passage 14, the injection nozzle side Since it is connected to the passage 13, the injection nozzle side passage 13 can be set longer. As a result, the flow can be rectified in the injection nozzle side passage 13, and this aspect also contributes to an increase in the flight distance of the ultra-high pressure jet liquid.

  If the inlet-side passage 12, the first and second intermediate passages 14, 15 or the injection nozzle-side passage 13 are formed in a curved shape, rectification is not performed at the outlet of the curved passage. The first and second intermediate passages 14 and 15 and the injection nozzle side passage 13 are respectively formed in a straight line so that the flow of liquid is adjusted on the outlet side (downstream side) of each passage so that there is no turbulent flow. ing.

  The same applies to the bent portions (corner portions) of the ultrahigh-pressure liquid passage 11. If each bent portion is rounded in an arc shape, turbulent flow is likely to occur here. Therefore, the bent portion of the ultrahigh pressure liquid passage 11 is formed at the corner portion.

  Further, the inner surface of the ultrahigh pressure liquid passage 11 and the hardener injection nozzle N are mixed with cemented carbide 16 such as tungsten carbide and cobalt to reduce wear caused by the hardener and to provide wear resistance. It is made of cemented cemented carbide.

  Next, it piles in the ground by the ground improvement method according to the present invention by the single tube type super high pressure injection method such as the CCP method using the injection tube rod 2 (single tube) with the monitor mechanism 1 attached to the tip. A construction procedure for vertically creating a solid-like solid body (improved body, hereinafter the same) P will be described below with reference to FIGS. 3A is a drilling process diagram using an injection tube rod, FIG. 3B is a process diagram for creating a pile-like solidified body, and FIG. 3C is a drawing process diagram of an injection tube rod. Hereinafter, it demonstrates in order of a process.

(1) Drilling step by injection tube rod As shown in FIG. 3 (a), a boring machine M is installed on the ground, and a target drilling depth is obtained while water or bentonite mud is ejected from the drilling hole by the injection tube rod 2. Do until.

(2) Formation Step As shown in FIG. 3 (b), in the formation step, the injection tube rod 2 is pulled up while being continuously rotated together with the monitor mechanism 1, and at the same time, the ultra high pressure curing material G is cured with a curing material injection nozzle. N is continuously ejected from N, and the surrounding ground is cut by the swirling jet, and the soil particles and the hardener are mixed and stirred, and a pile-like solidified body P is formed in the cutting area as shown in FIG. Create. As the pile-shaped solid body P, for example, the injection tube rod 2 is continuously rotated together with the monitor mechanism 1 to form a circular cross section as shown in FIG.
Alternatively, the injection tube rod 2 is rotated intermittently by repeatedly stopping and rotating every 45 ° (injection stop angle θ) while rotating the injection tube rod 2 together with the monitor mechanism 1 as shown in FIG. As shown in (b), the cross-section radial columnar solidified body P can be formed by repeatedly stopping and rotating every 22.5 ° (injection stop angle θ) during one rotation.
Furthermore, by alternately repeating injection of high-pressure jet (for example, 40 °) and stop of injection (for example, 140 °), a solidified body (water blocking wall) P having a butterfly cross section as shown in FIG. Can be created.

  What should be noted here is a configuration in which the corner corners α1 to α4 existing in the ultrahigh-pressure liquid passage 11 from the inlet 9 of the monitor mechanism 1 to the curing material injection nozzle N are all set within 50 °. Therefore, even when the discharge amount of the ultra-high pressure liquid (curing material) increases in the ultra-high pressure liquid passage 11, the generation of turbulent flow can be prevented, and the ultra-high pressure liquid smoothly enters the curing material injection nozzle N. Therefore, the jet cross section of the jetted ultra-high pressure jet can be made circular and the size of the circular cross-section can be reduced, and the flying distance of the super-high pressure jet liquid can be greatly increased. It is a point that can make a breakthrough in the enlargement of the formed diameter. Further, since each of the inlet side passage 12, the first and second intermediate passages 14, 15 and the injection nozzle side passage 13 is formed in a straight line with respect to the direction of liquid flow, the flow of the liquid is discharged to the outlet of each passage. This is a point that can be adjusted on the side (downstream side), so that a flow without turbulent flow can be effectively and surely obtained.

(3) Pulling-out process of injection pipe rod After completion of the formation, as shown in FIG. 3 (c), the supply of the ultra-high pressure hardener is stopped and the injection pipe rod 2 is pulled out to the ground. In addition, after pulling out the injection pipe rod 2, the inside of the injection pipe rod 2 is washed with fresh water and moved to the next formation point. Further, the hole 20 generated above the solidified body P by drawing out the injection tube rod 2 is filled with mud, mortar, or the like.

  The monitor mechanism 1 of the above embodiment has a single tube structure, but instead of this, as shown in FIG. 7, a double tube structure monitor mechanism 1 may be employed. This double-pipe structure monitoring mechanism 1 is attached to the distal end side of a double-pipe injection pipe rod 2 having an ultra-high pressure hardener passage 4 and a compressed air passage 21. The upper end portion of the ultrahigh pressure hardened material passage 4 is in communication with the ultrahigh pressure hardened material inlet 6 of the double tube swivel 5 shown in FIG. 8, and the compressed air passage 21 is in communication with the compressed air inlet 5a provided in the swivel 5. To make. The double-pipe monitor mechanism 1 is connected to the ultrahigh-pressure hardener inlet 6 of the swivel 5 and the ultrahigh-pressure hardener passage 4 in the double-tube injection pipe rod 2. A double pipe structure monitor having an ultra high pressure liquid passage 11 having the same structure as the passage 11 and a compressed air passage 23 communicating with the compressed air inlet 5a of the swivel 5 via the compressed air passage 21 in the injection pipe rod 2 A pipe 10, a single hardener injection nozzle N provided at the lower end of the ultrahigh pressure liquid passage 11, and a lower end of the compressed air passage 23 are provided so as to surround the hardener injection nozzle N. A compressed air injection nozzle 22 is provided. In addition, the inner surface of the ultrahigh pressure liquid passage 11 and the hardener injection nozzle N are mixed with tungsten carbide and cobalt in order to reduce wear due to the hardener and to provide wear resistance as in the case of the above embodiment. The cemented carbide 16 is sintered.

  The double-pipe structure monitoring mechanism 1 shown in FIG. 7 is for single injection having a single hardener injection nozzle N, but instead of this, two hardener injections as shown in FIGS. It is also possible to adopt a double-pipe structure monitor mechanism 1 for both injections having nozzles N1 and N2.

  The double-tube structure monitoring mechanism 1 for both injections is provided with two hardener injection nozzles N1 and N2 on the tube side of the monitor tube 10.

  That is, the double-tube structure monitoring mechanism 1 for both injections communicates with the ultrahigh-pressure hardener inlet 6 of the swivel 5 via the ultrahigh-pressure hardener passage 4 in the double-tube injection pipe rod 2. Compressed air communicating with the two ultrahigh pressure liquid passages 11, 11 having the same structure as the ultrahigh pressure liquid passage 11, and the compressed air inlet 5 a of the swivel 5 and the compressed air passage 21 in the injection pipe rod 2. A monitor pipe 10 having a double-pipe structure having a passage 23; two hardener injection nozzles N1, N2 provided on the pipe side portion of the monitor pipe 10 so as to communicate with the lower end of each ultrahigh pressure liquid passage 11; The compressed air injection nozzle 22 is provided at the lower end of the compressed air passage 23 and is provided so as to surround each of the curing material injection nozzles N1 and N2.

The two hardener injection nozzles N1 and N2 for injecting the ultra-high pressure liquid in the opposite direction are attached to the tube side portion of the monitor tube 10 in the direction perpendicular to the tube axis.
In the present embodiment, as shown in FIG. 10, the directions of both the stiffening material injection nozzles N1 and the other stiffening material injection nozzles N2 are shifted by a deviation angle S so that they are not parallel to each other. ing. Specifically, when viewed in a direction parallel to the axis of the injection tube rod 2, an imaginary line Z that intersects with the axes a and b of the hardener injection nozzles N1 and N2 (in this example, the imaginary line Z is a monitoring mechanism). 1), the direction of the axis a of one of the hardener injection nozzles N1 measured from this imaginary line Z (the angle formed by the imaginary line Z and the axis a) is θ1, Assuming that the direction of the axis b of the other cured material injection nozzle N2 measured from the line Z (the angle formed by the imaginary line Z and the axis b) is θ2, θ1 = θ2 + S.
However, the curing material injection nozzles N1 and N2 may be provided so that the axes a and b are parallel to each other.

  In each of the above embodiments, the spray nozzles provided at one or two locations have been described. However, the spray nozzles may be provided at three or more locations.

DESCRIPTION OF SYMBOLS 1 Monitor mechanism 2 Injection pipe rod 4 Super high pressure hardening material passage 5 Swivel 9 Inlet 10 Monitor pipe 11 Super high pressure liquid passage 12 Inlet side passage 13 Injection nozzle side passage 14 1st intermediate passage 15 2nd intermediate passage 16 Cemented carbide N, N1, N2 Curing material injection nozzle P Solidified body α1-α4 Corner corner bend in ultra high pressure liquid passage

Claims (3)

The injection tube rod is inserted to the target depth in the ground, and the hardened material is press-fitted at a very high pressure from the hardener inlet of the swivel attached to the upper portion of the injection tube rod, and the monitor mechanism assembled to the lower portion of the injection tube rod is cured. The super high pressure hardened material is continuously jetted from the material jet nozzle in the pipe radial direction, the jet pipe rod is driven to rotate, and the surrounding ground is cut and stirred by the high pressure jet of the super high pressure hardened material. In the ground improvement method,
The ground improvement method according to claim 1, wherein all corner corners in the ultra-high pressure liquid passage from the entrance for receiving the ultra-high pressure hardener to the hardener injection nozzle of the monitor mechanism are set within 50 °.   An inlet for receiving an ultra-high pressure hardener, a hardener injection nozzle, and an ultrahigh-pressure liquid passage formed between the inlet and the hardener injection nozzle. A monitor mechanism characterized in that all corner corners in the ultra-high pressure liquid passage are set within 50 °.   3. The monitor mechanism according to claim 2, wherein an inner surface of the ultra high pressure liquid passage is formed of a cemented carbide.

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