JP4944926B2 - Ground hardening layer construction method and its equipment - Google Patents

Description

  The present invention is provided with two stages of stirring blades extending in a cross-shaped direction, and an injection rod provided with an injection nozzle that injects downward into the upper stirring blade is inserted into the target ground, while spraying the ground improvement material from the injection nozzle, The present invention relates to a ground hardened layer construction method and an apparatus for creating a ground hardened layer in a target ground by rotating an injection rod up and down.

  Conventionally, for foundation support and reinforcement support for soft ground, there have been many ground hardening material injection methods for stirring and excavating 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, and the lower portion of the stirring blade from the injection nozzle provided on the injection rod side wall or It is difficult to cope with the increase in rotational torque by the injection of the hardener toward the top.

  Also, in the method of injecting horizontally from the mounting base of the lower stirrer blade during excavation and lifting, which is used as a medium pressure injection mechanical stirring method (CMS system), the tip of the blade is reached when the diameter is larger than φ1400 Therefore, there is a problem that the injection energy is attenuated and the effect of reducing the rotational torque of the machine is lowered.

  Furthermore, in the case of a large diameter of φ1400 or more, even if a large apparatus is used, the hardened material does not reach the outer peripheral part of the improved diameter depending on the condition of the target ground, and there is a hardening failure in the outer peripheral part of the formed ground hardened layer. There is a problem that there is a risk of occurrence, and uneven mixing of the agitated soil and the hardener is likely to occur.

  The present invention is intended to address the above-described problem, and the lower stirrer blade is obtained by spraying the ground hardening material vertically or obliquely downward from an injection nozzle provided on the blade abdomen of the upper stirrer blade. The target ground to be cut is reliably excavated and crushed to greatly reduce the rotational torque.

  In addition, the nozzle position for the lower injection is set by shifting one side to the tip side of the stirring blade and the other side to the base side, and the rod is rotated so that the injection locus draws a double circle to cut the lower ground. It is configured so that a wider range of soil is excavated and crushed.

  Furthermore, by injecting the hardener horizontally from the mounting base of the lower stirrer blades along the stirrer blades, the directions of excavation jets are mixed to prevent co-rotation in the viscous ground and the ground crushing force and Since the reach of the hardener jet has also been extended, it has become possible to implement large-diameter ground improvements that were previously impossible with small machines.

  In this way, by using cooperative injection of the lower injection from the upper stirring blade and the horizontal injection from the mounting base of the lower stirring blade for the stirring blade of φ1200 or less, the excavation and crushing force of the soil is remarkably enhanced. Construction on hard ground with a value of 15 or more was made possible, and the stirring and mixing effect could be enhanced.

  Since the present invention is configured as described above, the rotational torque in the ground of the stirring injection rod can be greatly reduced, the excavation and crushing force of the soil is increased, the excavation and crushing of a wide range of soil, and further the extension of the reach of the hardener jet flow Based on this, various construction effects can be expected by changing the ejection amount, injection pressure, injection site, and injection angle of the curing material according to the purpose of construction. be able to.

The perspective view of the whole apparatus which shows the Example of this invention and shows the construction state flaw which inserts a stirring injection | pouring rod into object ground and creates a ground hardening layer Similarly, an enlarged perspective view of the stirring injection rod tip monitor unit showing a state in which the lower stage stirring blade is jetted in the horizontal direction along the stirring blade along with the lower jet from the jet nozzle of the upper stage stirring blade. Similarly, an enlarged side view of the tip monitor section showing the state of attachment of the upper and lower stirring blades to the stirring injection rod and the state of the injection nozzle and the curing material channel Similarly, enlarged bottom view of the tip monitoring part of the stirring injection rod Similarly, in addition to the obliquely downward injection from the outer inclined nozzle set on the blades of the upper stirring blades, the situation where the upper stirring blades and the lower stirring blades are injected horizontally from the mounting base of the lower stirring blades along the respective stirring blades. Enlarged vertical cross-sectional side view of the stirring injection rod tip monitor section showing the position and injection direction of each injection nozzle in a plan view, with the extension direction discarded. Similarly, a vertical cross-sectional side view of the construction status showing the situation when the stirring injection rod is inserted and lowered into the target ground Similarly, a longitudinal sectional side view of the construction status showing the status of the diameter expansion injection in the ascending process of the stirring injection rod Similarly, a longitudinal cross-sectional side view of the construction situation showing the situation in which the diameter of the root portion of the hardened layer is expanded by the diameter expansion injection in the ascending injection rod raising process

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a stirring injection rod. Upper stirring blades 11A and 11B are set to protrude from the left and right at the tip monitoring portion M, and the lower stirring blades 12A and 12B intersect with the upper stirring blade in a cross shape at a predetermined interval below the upper stirring blade 11A. Is set.

  The upper stirrer blades 11A and 11B are provided with an injection passage 21 that branches from the hardened material pumping passage 2 provided on the rod 1 and extends toward the tip of the blade. 22a and 22b are opened. The lower injection nozzles 22a and 22b are provided with a plurality of preliminary nozzle holes 22c at a predetermined interval, and the nozzle tip 23 is fitted into the nozzle hole that is operated by selecting the position according to the construction conditions, and is not used. If the cover chip 24 is fitted and closed in the nozzle hole, it is possible to flexibly cope with the construction conditions.

  The lower stirring blades 12A and 12B are planted with a torsional inclination with respect to the rod 1 at an interval of about 300 mm from the upper stirring blade 11 and equipped with a cutter bit 3 on one side of the lower surface side. A horizontal injection nozzle 31a is set along the stirring blade toward the tip of the stirring blade at the upper part of the attachment base of 12A.

Further, a horizontal injection nozzle 31b is set along the stirring blade toward the tip of the stirring blade at the lower portion of the mounting base of the stirring blade 12B, and a hardener jet is abutted against the upper and lower surfaces of the lower stirring blade, resulting in a flight distance. It is configured to elongate and buffer the collision resistance between the blade surface and the stirring earth and sand to increase the stirring and mixing force of the stirring blade.
In addition, 31c is a preliminary | backup nozzle hole, The position can be selected according to construction conditions similarly to the case of the said downward injection nozzle.

The stirring injection rod 1 includes the upper stirring blade 11 and the lower stirring blade 12 configured as described above at the tip portion, and can be extendedly joined by a claw joint by attaching a monitor portion M having a drilling blade 13 at the tip. Consists of rods.
Further, the nozzle tip 23 for selecting and fitting the position of the nozzle holes 22 and 31 from the spare nozzle holes is angled in the injection direction in the tip in addition to the straight direction, and the injection nozzle is inserted by inserting the tip. A plurality of types of nozzle tips 23 are prepared so that the injection direction of the nozzles can be adjusted.

  The rear end is connected to a curing material supply hose 25 connected to the curing material plant via the swivel 14, and receives the slurry-like curing material prepared and supplied in the curing material plant through this, and the upper stage is supplied by the curing material pumping flow path 2. The lower injection nozzles 22a and 22b that open to the stirring blades 11A and 11B, the horizontal injection nozzle 31a at the upper part of the attachment base of the lower stirring blade 12A, and the horizontal injection nozzle 31b at the lower part of the attachment base of the 12B are pressure-fed. It is injected into the target ground G in the form.

  15 is a spindle leader that leads the raising and lowering drive of the stirring injection rod 1 and is supported by the mother machine and the leader machine 17 installed on the construction ground, and the raising and lowering drive is carried by holding the stirring injection rod 1 rotatably. It takes the lead as a main shaft and gives the rod 1 rotational drive by the rotational drive mechanism 16.

  If the hardened material is pumped from the hardener plant while rotating the stirring / injecting rod 1 configured as described above, the hardened material passes through the pumping flow path 2 so that the lower jet nozzles 22a and 22b, and further the horizontal jet nozzles 31a and 31b. However, the jet flow from the lower injection nozzle 22a drills and crushes the ground immediately before the lower stirring blade 12A rotates downward or obliquely downward, and draws a crushing trajectory R around the outer circumference. Then cut the ground.

  Immediately after this crushing trajectory, the cutter bit 3 of the lower agitating blade 12A turns and cuts, and further, the jet flow from the injection nozzle 22b perforates and crushes the ground just before the lower agitating blade 12B rotates downward or obliquely, The crushing trajectory Rs is drawn in a circumferential shape, and immediately after that, the cutter bit 3 of the lower stirring blade 12B is rotationally cut.

  Simultaneously with the downward injection from the upper stirring blade 11, the curing material injection from the horizontal injection nozzles 31 a and 31 b set to the mounting base of the lower stirring blade 12 is performed. The nozzle 31 a is injected from the upper portion of the mounting base of the stirring blade 12 A. Aiming at the tip of the blade, the jet is a little slanted along the upper surface of the agitating blade, repels the viscous soil that sticks to the blade surface, and is guided to the blade surface to extend the flight distance.

  The nozzle 31b is aimed at the blade tip from the lower part of the mounting base of the stirring blade 12B, and the jet flow is guided to the lower surface of the stirring blade and repels the viscous soil that sticks to the blade surface. It is stretched. In this way, the nozzles 22a, 22b, 31a, 31b perforate and crush the target ground in a multifaceted manner without colliding with each other, and the stirring blades stir and mix the soil in cooperation with this, so in the ground of the stirring injection rod The rotational torque can be greatly reduced, and the rod 1 can be smoothly lowered and inserted.

  When the predetermined depth is reached, the rod 1 is rotated in the reverse direction with respect to the rotation at the time of lowering, and the rod is lifted and pulled up again while injecting the hardener, so that the cylindrical ground in the target ground The hardened layer W is created, and the foundation support and reinforcement support of the soft ground are performed, but whether to change the operation mode at the time of lowering the rod and at the time of raising and lowering, or whether to change the hardened material pumping condition, It depends on the construction purpose and environmental conditions.

  In the case of normal construction, for example, at the time of insertion and descent of the stirring injection rod into the target ground, the cement milk is injected at a discharge rate of 100 liter / min from the upper stirring blade nozzle at a spraying pressure of 5 to 15 Mpa at a discharge rate of 100 liters / min. By rotating, the rotational torque at the time of lowering of the rod is reduced, and at the time of rising, the cement milk is further rotated at 10 to 30 rpm while being injected at an injection pressure of 10 to 30 Mpa and a discharge amount of 150 liter / min. A diameter-enlarging layer of φ1200 could be formed with the stirring and injection rod.

  In this case, the standard diameter layer of φ1000 is rotated at 30 to 50 rpm while being injected at a cement milk injection pressure of 5 to 15 MPa and a discharge amount of 100 liters / min.

  In Example 2, as shown in FIG. 8, when moving from the downward insertion to the pulling upward, the curing material injection pressure from the upper stirrer blade nozzle at the time of downward insertion is set to 5 to 15 MPa, while the discharge amount is being injected at 100 liters / min. Rotate at 30-50 rpm, rotate at a speed of 10-30 Mpa while injecting at a predetermined length of 10-30 Mpa and a discharge rate of 150 liters / min at the time of pulling up, and above that, the injection pressure is again 5-15 Mpa The foundation was constructed with a base having a larger diameter than the hardened layer of the surface layer by rotating at 30-50 rpm while spraying at a discharge rate of 100 liters / min.

  Moreover, about creation of the said enlarged diameter part, not only a base root part but a diameter can be expanded for every predetermined space | interval, and it can also produce in a bamboo-node-shaped hardened layer. In addition to the means for increasing the injection pressure, in addition to the means for increasing the injection pressure, the nozzle tip 23 is provided with an angled injection hole so that the lower injection of the upper stirring blade is directed toward the outside of the stirring blade. The trapezoid hypotenuse jet trajectory can be configured to form the hardener injection layer W with a large diameter.

  The ground hardened layer construction method and the apparatus according to the present invention are as described above, and the mechanical stirring by the stirring blade is combined with the multi-faceted non-crossing jet combined stirring, so that the cutting soil and the hardened material are highly mixed and homogeneous. It is possible to create an improved mixed layer, and it can be used to actively promote the use of land that could not be used due to the weak geology by the efficient strengthening of soft ground.

DESCRIPTION OF SYMBOLS 1 Stirring injection rod 11A Upper stirrer blade 11B Upper stirrer blade 12A Lower stirrer blade 12B Lower stirrer blade 13 Excavation blade 14 at the tip of the monitor part Swivel 15 Spindle leader 16 Rod rotation drive mechanism 17 Leader machine 2 Curing material pressure feed path 21 Injection flow path 22a Lower injection nozzle 22b of upper stirring blade 11A Lower injection nozzle 22c of upper stirring blade 11B Preliminary nozzle hole 23 of lower injection nozzle Nozzle tip 24 Cover chip 25 Curing material supply hose 3 Cutter bit 31a Horizontal injection nozzle of lower stirring blade 12A 31b Horizontal injection nozzle 31c of lower stirring blade 12B Preliminary nozzle hole G of horizontal injection nozzle Target ground M Monitor section R of rod tip Outer circumferential crushing trajectory Rs Inner peripheral circumferential crushing trajectory W Preparation hardened material layer

Claims (7)

  An upper agitating blade that extends from side to side with a lower injection nozzle on the flank, and a lower agitating blade that crosses in a cross shape at a predetermined interval are provided below the upper agitating blade. The stirrer blades are lowered and raised or both rotated while rotating the stirring injection rod while pumping the hardened material to the stirring injection rod set with the horizontal injection nozzle at the lower part of the base of the stirring blade and jetting high pressure from each nozzle. A ground hardened layer construction method characterized by   One of the lower injection nozzles provided on the upper stirring blade is set on the tip side of the stirring blade and the other is set on the base side, and the tip-side lower injection nozzle jet crushes the outer periphery of the target ground in a circular shape, The ground hardening layer creation method of Claim 1 comprised so that a base side downward injection nozzle jet might crush the inner peripheral part of object ground in the shape of a circumference.   Both of the lower injection nozzles provided on the upper stirring blade are inclined toward the outer periphery of the target ground at the tip side of the stirring blade so that the jet flow from the injection nozzle reaches the outside of the length range of the stirring blade. The ground hardened layer construction method according to claim 1   One or both of the lower injection nozzles provided on the upper stirring blades are inclined toward the outer periphery of the target ground at the tip side of the stirring blades, and the jet flow from the injection nozzles is controlled by controlling the injection pressure from the injection nozzles The ground hardened layer construction method according to claim 1, wherein a ground hardened layer having a large diameter portion and a small diameter portion is created by changing the reach distance.   An upper agitating blade that extends from side to side with a lower injection nozzle on the flank, and a lower agitating blade that crosses in a cross shape at a predetermined interval are provided below the upper agitating blade. A ground hardening layer forming device comprising a stirring injection rod supported by a rotating vertical drive mechanism, each having a horizontal injection nozzle set at the lower part of the base of the stirring blade.   For each injection nozzle, a plurality of nozzle holes are provided in the site where the setting position needs to be changed depending on the installation conditions, and the nozzle tip is inserted into the nozzle hole selected according to the installation environment to form the injection nozzle, and other nozzle holes 6. A ground hardened layer forming device according to claim 5, wherein a cover chip is inserted and closed.   A nozzle tip that is inserted into a nozzle hole to form an injection nozzle is formed by forming an injection hole with a predetermined angle, and an injection nozzle that is injected in a predetermined angular direction by being inserted into the nozzle hole by angle selection. 7. The ground hardened layer forming device according to claim 6, wherein the ground hardened layer forming device is formed.

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