JP2017031735A - Ground hardening layer establishment method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of being unable to avoid a hollow phenomenon, that is, a doughnut phenomenon caused in a ground hardening layer without sufficiently spreading a hardener, since injection to the horizontal direction is set as a main stream in hardener injection, in hardening layer establishment of conventionally combinedly using direct agitation by an agitation blade, fluid agitation by a hardener jet flow and hardener injection.SOLUTION: A plate-like twist blade 11 whose installation base part 11a and tip part 11b incline in the inverse direction to the injection rod axis, is projected on both left-right sides of an injection rod, and is constituted so that a side flow passage for forcibly feeding a hardener opens as an injection nozzle 14 on the tip of the plate-like twist blade by penetrating through the inside of the plate-like twist blade.SELECTED DRAWING: Figure 1

Description

  The present invention is to improve the ultra-soft ground by an injection rod using a stirring blade, to avoid the hollow phenomenon generated in the ground hardened layer formed by the stirring injection of the target ground, that is, to avoid the donut phenomenon and increase the stirring efficiency. The present invention relates to a ground hardened layer construction method and an apparatus therefor.

  Conventionally, for the foundation support and strengthening support of soft ground, there have been many ground hardening material injection methods that stir and excavate the target ground by rotating the ground hardening material injection rod while jetting the ground hardening material at high pressure. However, depending on the construction environment and the softness of the ground, there is a problem that the efficiency is poor and the stirring force is insufficient.

  Correspondingly, direct stirring by a stirring blade is performed, and in order to increase the diameter of the hardened material injection layer, as shown in Patent Document 1, for example, an injection nozzle is provided at the tip of the stirring blade. An injection nozzle has also been set on the stirring blade, for example, by providing a stirrer in the horizontal direction.

  However, since the conventional curing material injection is mainly in the horizontal direction, there is a problem in the adjustment of the direct stirring by the stirring blade and the fluid stirring by the curing material jet, the curing material does not spread sufficiently in the stirring area, Uneven mixing of the soil and the hardener is likely to occur, and a further problem remains in the reliable and uniform stirring and mixing of the soil.

  In order to cope with such a problem of unevenness in mixing, as a means for stirring the ground improvement material and the soft soil, for example, as shown in Patent Document 2, an injection nozzle that injects obliquely downward to obliquely upward is provided on the injection rod, A method and apparatus have also been proposed in which three-dimensional jet stirring and injection is performed by intersecting jets, and further direct stirring is performed by a stirring blade provided on the top.

  In addition, in order to prevent the injected hardened material from being diluted outflow due to excessive stirring or use of cutting water, a diffusion prevention plate is set at the tip of the stirring blade as shown in Patent Document 3, It has also been proposed to provide an injection nozzle that injects in an oblique direction of the injection rod as in Literature 4, and to inject the curing material from the injection nozzle toward the tip of the stirring blade.

JP 50-107714 A JP-A-6-146260 Japanese Patent Laid-Open No. 9-296439 JP-A-2005-76212

  When stirring directly with a stirring blade, an increase in rotational torque generated by the resistance of the ground applied to the rotation of the injection rod is a problem, which greatly affects work efficiency. However, in the case of the above prior art, if a diffusion prevention plate is set at the tip of the stirring blade, the rotational torque for rotating the injection rod increases.

  Also, in the method of jetting and pulling up, which is used as a jetting machine stirring method, the method of jetting horizontally from the tip of the lower stirrer blades is a hollow phenomenon that occurs in the ground hardened layer formed by stirring injection of the target ground, that is, a donut There is a problem that the phenomenon cannot be avoided.

  Furthermore, when the diameter of the hardened layer to be created is a large diameter of φ1400 or more, the hardened material does not reach the outer peripheral part of the improved diameter depending on the situation of the target ground even if a large apparatus is used. There is a risk that poor curing occurs at the outer peripheral portion of the hardened layer, and there is a problem that uneven mixing of the agitated soil and the hardener is likely to occur.

  Furthermore, when the injection rod is inserted into the target ground and switched from the lower injection during excavation to the side injection for stirring injection, a situation occurs in which the fluid flows backward to the side branch flow path due to the reverse pressure from the surrounding ground. There is a problem to do.

  The present invention is intended to address the above-described problems, and is provided with a plate-like twisted wing projecting from the left and right sides of the injection rod with the mounting base and the tip inclined in the opposite direction with respect to the injection rod axis. The side flow path for pressure-feeding is configured to pass through the inside of the plate-shaped twisted wing and open as an injection nozzle at the tip of the plate-shaped twisted wing.

  With this configuration, the hardened material sprayed from the side injection nozzle is caught in the flow of the swirling motion of the surrounding soil caused by the rotation of the plate-like twisted wing, and is guided up and down the plate-like twisted wing, thereby improving the hardened material. It is introduced into the inner periphery of the caliber.

  Further, by configuring the blades of the plate-like twisted wings to be curved in a corrugated manner, the agitated soil lifted on the blades is swung on the corrugated curved surface, so that more precise crushing and mixing are performed. . In addition, a guide groove is engraved along the twisting direction on the outer surface of the plate-like twisting blade so that the agitating soil surrounding the plate-like twisting blade is actively synchronized with the swivel rotation of the plate-like twisting blade. Configured.

  Furthermore, the curing material flow path provided in the plate-shaped twisted wing is configured in the shape of a nozzle that reduces the entire diameter in a taper shape from the base to the tip, and is configured to expand the volume of the animal pressure structure, and the curing material jet Increased the injection power.

  In addition, a differential pressure valve and a check valve are set at each branch inlet of the branch side flow channel that opens on both sides of the injection rod, and stirring injection is performed from the lower injection during excavation when the injection rod is inserted into the target ground. When switching to side injection for this purpose, the occurrence of a situation where the fluid flows backward to the side branch flow path due to the back pressure from the surrounding ground is prevented.

  Since the present invention is configured as described above, the ground hardened layer formed by the stirring injection of the target ground without relying on the hardener injection toward the lower or upper part of the stirring blade directly connected to the increase of the rotational torque. The hollow phenomenon that occurred, that is, the donut phenomenon could be avoided.

  In addition, without using a means for complicating the structure of the injection rod, such as air-winding injection using a superposition jet nozzle for strengthening the crushing force of the hardener jet, the top and bottom sides of the injection rod with a single tube A plate-shaped twist that is provided with a hardening material pumping channel that branches into a side channel that opens in the abdomen, with the mounting base and tip protruding from the left and right sides of the injection rod inclined in the opposite direction with respect to the injection rod axis A configuration in which a side flow path is opened as an injection nozzle at the tip of the wing enables reliable and uniform stirring and mixing of soil without uneven mixing of soil and hardener.

The vertical side view of the injection rod front-end | tip part which shows the Example of this invention and shows the structure of the hardening | curing material pumping flow path branched into the side flow path opened in the downward direction and both sides antinodes in the injection | rod end part. Similarly, a plate-like twist showing the state of undulation on the outer surface of the blade of the embodiment constructed by curving the blade plate of the plate-like twisted wing, and the state of the guide groove engraved on the outer surface of the plate-like twisted wing An enlarged perspective view of a wing. Similarly, the top view which made the injection rod which shows the attachment condition of the plate-shaped torsion blade to an injection rod, and the state of an injection | spray nozzle and a hardening material flow path by the cross section by the XX line of FIG. Similarly, the expansion side view of the plate-shaped twisting wing attachment part of the injection rod which looked at the attachment base part of the plate-shaped twisting wing which shows the attachment condition of the plate-shaped twisting wing to an injection rod from the front-end | tip part of the wing | blade. Similarly, the expansion side view of the plate-shaped twisting wing attachment part of the injection rod which looked at the plate-shaped twisting wing from the side surface part side which shows the attachment condition of the plate-shaped twisting wing to an injection rod. Similarly, the whole side view which made the cross section the principal part which shows the construction condition of ground hardened layer construction by this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Reference numeral 1 denotes an injection rod, and the hardening material pumping flow path 2 is constituted by a single pipe having a joint structure to be appropriately coupled. It branches into the flow paths 2a and 2b, and the upper end is connected to the material supply hose 41 via the swivel 15.

On both sides of the distal end monitoring portion M of the injection rod 1, plate-like twisted wings 11A and 11B in which the side flow paths 2a and 2b are provided are set so as to protrude from side to side. The plate-like twisted wings 11A and 11B are formed in a twisted shape in which the attachment base portion 11a and the tip end portion 11b are inclined in the opposite directions with respect to the injection rod axis 13, and the blade surface is swiveled by the rotation of the injection rod 1. It is configured as follows.
In addition, a plurality of scratching claws 16 and 16 are implanted along the edges of the blade edges of the plate-like twisted wings 11A and 11B.

  Further, as another embodiment of the plate-like twisted wing, the bladed plate of the plate-like twisted wing is curved in a waveform as shown in FIG. By rocking on the curved surface, more precise crushing and mixing is performed. The vane plate does not always have to be wave-curved, and may be formed only in a twisted shape as shown in FIG.

  The plate-like twisted wings are also provided with one or a plurality of guide grooves 12 along the twist direction on the outer surfaces of the plate-like twisted wings 11A and 11B. The soil contact is involved in the swirling motion of the surrounding soil and guided up and down the plate-like twisted wings.

  The side flow passages 2a and 2b provided in the plate-like twisted blades 11A and 11B are configured in a nozzle shape that is tapered from the plate-like twisted blade attachment portion toward the tip, and the tip opening portion is an injection nozzle. 14 In addition, a differential pressure valve 3 and a check valve 31 are set at the branch inlets 22 and 22 of the branch side flow paths 2a and 2b, and the branch inlets 22 and 22 are caused by the fluid pressure of the fluid pumped by the differential pressure valve 3. The check valve 31 prevents the fluid from flowing back into the side branch flow path due to the back pressure from the surrounding ground. Reference numeral 14a denotes a nozzle tip that is detachably screwed to the tips of the plate-like twisted wings 11A and 11B, and is configured to be exchangeable so as to change the nozzle diameter according to the injection environment.

  The stirring injection rod 1 configured as described above is driven to rotate and descend while supplying the lubricating liquid to the injection rod 1 depending on the softness of the target ground, or is lowered as it is due to the gravity of the injection rod 1.

  That is, when the target ground is so soft that it is lowered as it is due to the gravity of the injection rod 1, if the hardening material is pumped through the material supply hose 41 and the swivel 15 from the hardening material plant (not shown) simultaneously with the lowering operation. The hardened material reaches the horizontal injection nozzles 14 and 14 of the side flow paths 2a and 2b that open on both sides of the lower flow path 21 through the pressure-feed flow path 2 and is injected into the target ground, and hardens while perforating and crushing the surrounding soil. While the material is filled, the ground is cut into a cylindrical shape to form a cylindrical hardened layer, and when a predetermined depth is reached, correction means such as injection of the hardened material from the lower flow path 21 is taken as necessary. The injection rod 1 is withdrawn.

  In the case where the softness of the target ground is low and rotation is performed while supplying the lubricating liquid to the injection rod 1, the sphere 23 that closes the lower flow path 21 is dropped from above the injection rod 1 at a predetermined depth to flow downward. If the passage 21 is closed and the hardener is pumped from the hardener plant or the like through the material supply hose 41 and the swivel 15, the hardener will be opened to the sides of the lower passage 21 through the pumping passage 2. The horizontal injection nozzles 14 and 14 are injected into the target ground, and the injection rod 1 is lifted while filling the hardening material while drilling and crushing the surrounding soil, and a hardened ground layer is formed in a cylindrical shape. is there.

  A differential pressure valve 3 and a check valve 31 are set at the branch inlets 22 and 22, and when the branch inlets 22 and 22 are opened and closed by the fluid pressure of the fluid pumped by the differential pressure valve 3, By rotating and descending while supplying the lubricating liquid, converting the supply fluid into a hardening material at a predetermined depth and raising the supply pressure, the differential pressure valve 3 is opened and the horizontal injection nozzles 14 in the side flow paths 2a and 2b, 14 is injected into the target ground. At that time, whether or not to block the lower flow path 21 depends on the construction purpose and environmental conditions. It is also possible to provide a differential pressure valve in the lower flow path 21 and operate by pressure flow pressure.

  When the lowering of the injection rod 1 reaches a predetermined depth, the rod 1 is lifted and pulled up again while spraying the hardener while changing the rotation direction of the rod 1 and rotating it in reverse to the rotation at the time of lowering. A cylindrical ground hardened layer W is created in the middle to build the soft ground and to support the foundation and strengthening. However, the operating mode is changed when the rod is lowered and when the lift is raised, and the conditions for feeding the hardened material are changed. Whether or not to do so depends on the construction purpose and environmental conditions.

  As an example of construction, a plate-like twisted wing of 150 to 200 mm in length is implanted on the flank of an injection rod 1 having a diameter of 90Φ, and is hardened with a jet pressure of 40 Mpa from a horizontal jet nozzle when it is lowered into the target ground. By expanding cement milk as a material at a discharge rate of 200 liters / min and rotating at 2 to 20 rpm, a diameter-enlarged layer having a diameter of 2,500 mm could be formed.

  The ground hardened layer construction method and the apparatus according to the present invention are a nozzle-shaped hardened material flow in which the stirring blade is a plate-shaped twisted blade as described above, and the diameter is reduced in a taper shape from the base to the tip of the plate-shaped twisted blade. It is possible to create a homogeneous improved mixed layer with extremely high degree of mixing of cutting soil and hardened material by combining physical agitation with multi-faceted wing shape by installing a road and efficiently strengthening soft ground It can be used to actively promote the use of land that could not be used due to its weak geology.

DESCRIPTION OF SYMBOLS 1 Stirring injection rod 11A Plate-shaped twisted blade 11B Plate-shaped twisted blade 11a Plate-shaped twisted blade attachment base 11b Plate-shaped twisted blade tip 12 Plate-shaped twisted blade guide groove 13 Injection rod axis 14 Horizontal injection nozzle 14a Injection Nozzle tip 15 Swivel 16 Claw of plate-like twisted blade 2 Hardened material pressure feed path 2a Branch side channel 2b Branch side channel 21 Lower injection channel 22 Branch inlet 23 Lower channel block sphere 3 Differential pressure valve 31 Check Valve 41 Material supply hose G Target ground M Monitor end W of rod end W Hardened material layer

Claims (9)

  At the distal end, a mounting base and a distal end portion in which the lateral flow path of the injection rod provided with a hardening material pumping flow path branched into a lateral flow path that opens downward and on both sides of the injection rod protrudes on both the left and right sides of the injection rod The hardened material is pumped to the injection rod that opens as the injection nozzle at the tip of the plate-shaped twisted blade that inclines in the opposite direction with respect to the injection rod axis, and the stirring injection rod is rotated while high-pressure injection is performed from the left and right nozzles. A ground hardened layer construction method characterized in that it descends, rises or both.   The ground hardening layer construction method of Claim 1 comprised so that agitation soil might be synchronized with the turning rotation of a plate-shaped twisting blade using the injection rod comprised by curving the blade plate of a plate-shaped twisting blade.   Claim 1 or Claim, wherein the agitating soil is synchronized with the swivel rotation of the plate-like twisted wing by using an injection rod in which a guide groove is engraved along the twist direction on the outer surface of the plate-like twisted wing. Item 2. A ground hardened layer construction method according to Item 2.   The hardening material flow path provided in the plate-like twisted wing is configured in a nozzle shape that is tapered in a taper shape from the base to the tip, and an injection rod configured to expand the volume of the animal pressure structure is used. The ground hardened layer construction method of Claim 1 or Claim 2 or Claim 3.   At the distal end, a mounting base and a distal end portion in which the lateral flow path of the injection rod provided with a hardening material pumping flow path branched into a lateral flow path that opens downward and on both sides of the injection rod protrudes on both the left and right sides of the injection rod Is a ground hardened layer forming apparatus in which an injection rod opening as an injection nozzle is supported by a rotary vertical drive mechanism at the tip of a plate-like twisted blade inclined in the opposite direction to the injection rod axis.   The ground hardened layer forming apparatus according to claim 5, wherein the blade plate of the plate-like twisted wing is bent into a wave shape.   The ground hardened layer forming apparatus according to claim 5 or 6, wherein a guide groove is formed on the outer surface of the plate-like twisted wing along the twisting direction.   8. The ground hardened layer forming apparatus according to claim 5, wherein the hardened material flow path provided in the plate-like twisted wing is configured in a nozzle shape having a tapered diameter from the base toward the tip. .   The ground hardening according to claim 5, 6 or 7, or 8 or 8, wherein a differential pressure valve and a check valve are set at each branch inlet of the branch side flow path opening on both sides of the injection rod. Layer creation device.