JP3964904B2 - Jet stirring method and jet stirring device - Google Patents

Description

The present invention relates to a jet stirring method and a jet stirring device capable of constructing a pile having a desired diameter and treating waste mud accompanying the creation as general residual soil.

  Generally, in construction and civil engineering work, if the target ground is soft, the ground is improved prior to this construction. As an improvement of the ground, it is usual to impregnate the ground with a ground hardening material that hardens the target ground.

Various methods are used to improve the ground, but the jet agitation method is widely adopted because it is excellent in workability and can reliably perform a wide range of improvements.
In the jet stirring method, a jet stirring device called a boring machine is used.
Generally, a boring machine has a high pressure applied to a boring machine body (also called a feeding device) that raises and lowers a spindle, a multi-tube rod supported by the spindle of the boring machine body, and a ground hardening material mixed with a mixer and an agitator. The high-pressure pump that pumps pressure, the hydraulic unit that drives the high-pressure pump, the compressor that mixes air into the ground hardened material pumped from the high-pressure pump, and the water tank that supplies water to the mixer by the pump.

The boring machine main body pulls up the multi-tube rod while rotating it and injects a mixture of ground hardening material and air at a high pressure from an injection nozzle provided at the lowermost monitor of the multi-tube rod.
Thus, a columnar stirring portion of the ground and the hardened material is formed in the target ground, and a pile-like solid material is created in the ground by hardening of the ground hardened material, thereby constructing a pile. At this time, a part of the soil replaced with the ground hardening material is discharged to the outside together with air as muddy water.
Japanese Patent No. 2717503 Japanese Patent No. 2844184

In such a jet stirring method, air is jetted into the ground from the spray nozzle together with the ground hardening material to stir the soil and the ground hardening material. At this time, cement milk used as a ground hardening material is sucked out by a phenomenon called air junction (mixed jet phenomenon). Thus, a part of the ground hardening material in the ground is sucked out from the excavation hole before being hardened and discharged to the outside.
For this reason, the amount of ground hardening material required for constructing a pile with a desired diameter is insufficient, and a phenomenon that the ground hardening material does not impregnate to a sufficient distance occurs, and the diameter is smaller than the actually planned diameter. There was a situation that would result in a pile.
Moreover, since the mud discharged | emitted from a drilling hole with cement milk must be processed as an industrial waste, the work on the site became complicated and the result was expensive.

    The present invention solves the above-mentioned problems, accelerates the hardening of the ground hardening material, prevents the outflow of the ground hardening material, constructs a pile of a desired diameter, and can treat the sludge accompanying the creation as a general residual soil It aims at providing a construction method and a jet stirring device.

In order to solve the above-mentioned problems, the present invention feeds a multi-tube rod into the ground, pulls up the multi-tube rod from the ground while rotating it, and at a high pressure from an injection nozzle provided on the multi-tube rod. In the method of improving the ground by injecting a ground improvement medium mainly composed of cement into the ground and stirring the ground to construct a pile of a predetermined diameter, a nozzle is provided at each of the lower ends of the multi-pipe rods. Injecting water up and down, and spraying water with compressed air from the upper injection unit within the range of predetermined growth and growth, cutting the ground improvement area and discharging the mud to the ground through the cutting hole The lower injection section is provided with two injection sections consisting of a central injection nozzle and surrounding injection nozzles on both sides of the multi-tube rod at the same height from the tip. Of the lower side injection part From the injection nozzle of the heart, the ground improvement medium composed mainly of cement milk, than the injection pressure of the ground improvement medium composed mainly of cement milk reactants has a property to harden the cement milk from the surrounding of the injection nozzle Also, by setting and spraying at a low pressure, immediately after jetting the ground improvement medium mainly composed of the cement milk, the pile is formed with a predetermined diameter by quickly curing with the reactant.
Further, the present invention is a method in which water is injected together with compressed air from the upper injection nozzle in the region of the ground improvement region to cut the ground, and the lower injection unit reaches the region of the ground improvement region. The purpose is to inject the ground improvement medium from the injection nozzle at the center of the lower injection unit and the reactant from the surrounding injection nozzles.
Furthermore, the present invention is that water glass-based sodium silicate is used as the reactant.
The present invention also feeds a multi-pipe rod into the ground, pulls up the multi-pipe rod from the ground while rotating it, and contains cement as a main component at a high pressure from an injection nozzle provided on the multi-pipe rod. In the jet agitating apparatus for constructing a pile having a predetermined diameter by injecting the ground improvement medium into the ground and agitating the ground, the lower end portion of the multi-tube rod is provided with an injection portion provided with a nozzle above and below, an injection nozzle for injecting water together with compressed air on the upper side injection unit provided with injection nozzles in the center on the lower side injection unit, the same from the tip of the two injection unit comprising a surrounding injection nozzle on both sides of the multi-tube rod provided at a height position, supplies the ground improvement medium for cement milk mainly to the injection nozzle of said central, Sementomi reactants has a property to harden the cement milk to the injection nozzle around the Than the injection pressure of the ground improvement medium composed mainly of click in that so as to supply injected is set to a low pressure.
Furthermore, the present invention resides in that the injection nozzles around the lower injection unit are inclined to the central injection nozzle side.
Furthermore, the present invention resides in that the injection nozzles around the lower injection unit are provided concentrically with the central injection nozzle.

As an effect of the present invention, cement milk can be prevented from flowing out and a pile having a predetermined diameter can be constructed. Since it is possible to prevent the cement milk from flowing out, it is possible to construct a large-diameter pile that is sufficiently impregnated with the cement milk.
Since cement milk is hardened early by the reactant immediately after jetting, cement milk does not flow out to the outside, so that the mud flowing out can be treated as general residual soil. Since the cement milk and the reactant are forcibly mixed, the hardening of the cement milk is promoted, and a pile in which the cement milk is uniformly impregnated can be constructed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a jet stirring device used in the jet stirring method of the present invention, and FIGS. 2, 3A and 3B show a monitor unit of the jet stirring device.
In FIG. 1, reference numeral 1 denotes an injection agitation device called a boring machine. The injection agitation device 1 includes a drive device 2 having a built-in hydraulic pump, and a feeding device 4 that moves the multi-tube rod 3 up and down. Yes. A monitor unit 5 is connected to the lowermost end of the multi-tube rod 3, and the monitor unit 5 is continuous with the multi-tube rod 3 as shown in FIGS. 2, 3 (a) and 3 (b). The cylinders 51, 52, 53, and 54 are concentric with each other and are moved up and down and rotated together with the multiple tube rod 3. The monitor unit 5 has a pair of injection nozzles 61 and 62 (injection unit) on the upper side and a single injection nozzle 71 (injection) on the lower side, with a fixed interval between the upper and lower parts, for example, about 1 to 2 m. Part).

  The upper injection nozzles 61 and 62 are provided on the outer cylinders 51 and 52 of the monitor unit 5, and the lower injection nozzle 71 is provided on the inner cylinders 53 and 54 of the monitor unit 5. The upper injection nozzles 61 and 62 are provided on the opposite sides of the monitor unit 5 in opposite directions. The upper injection nozzles 61 and 62 are configured such that water is supplied from between the cylinders 52 and 53 and compressed air is supplied from between the cylinders 51 and 52 and is injected into the ground as ultra-high pressure water. Has been.

The inner cylinders 53 and 54 are provided to extend downward from the outer cylinders 51 and 52, and the injection nozzle 71 is provided at the center as shown in FIGS. 4 (a) and 4 (b). The main injection nozzle 71a and the auxiliary injection nozzle 71b provided concentrically around the main injection nozzle 71a. The main injection nozzle 71a is connected to the inside of the cylinder body 54, and is configured to be supplied with a ground improvement medium mainly composed of cement as a hardener.
On the other hand, the auxiliary injection nozzle 71b is connected between the inner cylinders 53 and 54 and supplied with a reactive agent (reactive material) having a property of hardening cement milk, which is a main component of the ground improvement medium (hardening material). It is comprised so that. The auxiliary injection nozzle 71b is a cylindrical nozzle and is provided concentrically around the main injection nozzle 71a.
A water glass-based sodium silicate is used as a reactive agent that hardens the cement milk. The ratio of sodium silicate is 30 to 50% with respect to water.

Next, the case where a pile is constructed | assembled using a jet stirring construction method is demonstrated.
The multi-tube rod 3 is advanced into the ground 8 to a predetermined depth L, and the ground is drilled (see FIG. 1). L is determined by the range (l3) for constructing the pile + the depth to the top of the pile (l1 + l2). l1 indicates the depth of the concave portion formed on the ground surface for storing the mud discharged on the ground.
Next, while rotating the multi-tube rod 3, a predetermined speed, for example, 1 m is pulled up in about 15 to 16 minutes. Then, the super high pressure water 9 is jetted together with the compressed air from the upper jet nozzles 61 and 62 together with the lifting, and the ground 8 is cut (see FIG. 5). The discharged mud 10 generated by the cutting of the ground 8 is discharged from the excavation hole 11 around the multi-tube rod 3 to the concave portion of the ground surface by a lift effect.

  At this stage, the ground improvement medium and the reaction agent mainly composed of cement are not yet injected from the lower injection nozzle 71. Then, when the lower side injection nozzle 71 reaches the depth of the ground where the upper side injection nozzles 61 and 62 have started to inject, cement is mainly contained in the agitated ground 81 from the lower side main injection nozzle 71a. The injection of the ground improvement medium 12 is started. At the same time, injection of the reactant 13 having the property of hardening cement milk from the auxiliary injection nozzle 71b on the lower side is started (see FIG. 6). From the auxiliary injection nozzle 71b on the lower side, water glass-based sodium silicate is injected as the reactant 13. From the auxiliary injection nozzle 71b on the lower side, the reactant 13 is continuously or intermittently injected into the ground.

Then, the super-high pressure water 9 is jetted together with the compressed air from the jet nozzles 61 and 62 on the upper side and the ground 81 is cut, while the ground improvement medium 12 mainly composed of cement is supplied from the lower main jet nozzle 71a. From the auxiliary injection nozzle 71b on the lower side, water glass-based sodium silicate is injected as the reactant 13 (see FIG. 6). As shown in FIG. 7, the ground improvement medium 12 containing cement as a main component is hardened at an early stage by mixing the reactant 13 immediately after jetting from the main jet nozzle 71a. During this time, the monitor unit 5 is gradually pulled up while being rotated together with the multi-tube rod 3. The discharged mud 10 discharged from the excavation hole 11 to the ground does not contain the ground improvement medium, and can be treated as general residual soil.

When the upper injection nozzles 61 and 62 reach the upper end of the ground improvement zone, the injection of the compressed air and the ultrahigh-pressure water 9 injected from the upper injection nozzles 61 and 62 is stopped, and thereafter the lower injection nozzle The ground improvement medium 12 and the reactant 13 are injected from 71 to the ground improvement area (see FIG. 8). At this stage, the discharged mud is treated as industrial waste.
Thus, the cement milk of the ground improvement medium 12 injected from the lower main injection nozzle 71a is hardened early by forcibly mixing the reactant 13 injected from the lower auxiliary injection nozzle 71b. Since the pile 82 is constructed, the mixed air phenomenon is prevented and the ground improvement medium 12 is not discharged to the outside. Thus, since the ground improvement medium 12 is hardened early by the reactant 13 immediately after injection, a large-diameter pile 82 sufficiently impregnated with the ground improvement medium 12 can be constructed without flowing out to the outside. (See FIG. 9).

FIGS. 10 and 11 (a) and 11 (b) show another embodiment of the monitor unit 15 in which the same parts as those in FIGS. 2 and 3 are denoted by the same reference numerals. The nozzles 71 and 72 are provided on both sides of the monitor unit 15. The injection nozzles 71 and 72 are provided with concentric auxiliary injection nozzles 71b and 72b around the main injection nozzles 71a and 72a, respectively. And the ground improvement medium 12 which has cement as a main component is injected from the main injection nozzles 71a and 72a as a hardening material, and the reactive agent 13 for promoting hardening is injected from the auxiliary injection nozzles 71b and 72b. is there.
According to this embodiment, since the reactive agent 13 is injected around the ground improving medium 12 immediately after the ground improving medium 12 is jetted, the reactive agent 13 is forcibly mixed with the ground improving medium 12. be able to.

  FIG. 12 shows a modification of the lower side injection nozzle 71 (72) of the present invention. In this case, a pair of auxiliary injection nozzles 71c are provided around the main injection nozzle 71a, and the pair of auxiliary injection nozzles 71c are provided on the outlet side. Toward the center main injection nozzle 71a side so as to be inclined. In this way, as shown in FIG. 13, the reactant 13 can be forcibly mixed at a closer distance with the ground improvement medium 12 mainly composed of cement injected from the main injection nozzle 71a. In addition, the number of auxiliary injection nozzles 71c is not limited to two, and can be provided on the circumference such as 3, 4, 5, 6 or more as necessary. In addition, an arbitrary angle can be set as the inclination angle.

  Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the lower main injection nozzles 71a and 72a provided on both surfaces are provided at the same height position. It may be provided in a shifted manner. In addition, one of the diameters of the main injection nozzles 71a and 72a and the diameters of the auxiliary injection nozzles 71b and 72b can be increased and the other can be decreased. Further, the pressure of the reactant 13 injected from the auxiliary injection nozzles 71b and 72b is lowered with respect to the injection pressure of the ground improvement medium 12 mainly composed of cement as a hardening material injected from the main injection nozzles 71a and 72a. Thus, the reactant 13 can be mixed with the ground improvement medium 12 at a closer position. Furthermore, water glass sodium silicate was used as a reactive agent that hardens cement milk, but other reactive agents can be used, and other modifications within the scope that does not change the gist of the present invention. Needless to say, it can be implemented.

  It is a conceptual diagram which shows embodiment of the jet stirring apparatus used for the jet stirring method by this invention.   It is a longitudinal cross-sectional view which shows the monitor part of the jet stirring apparatus of the jet stirring method of this invention.   The monitor part of the jet stirring apparatus of the jet stirring method of this invention is shown, (a) is a longitudinal cross-sectional view, (b) is a side view of (a).   (A) is sectional drawing which shows the nozzle part of FIG. 3, (b) is a side view of (a).   It is a conceptual diagram which shows the operation | movement order of the jet stirring construction method by this invention.   It is a conceptual diagram which shows the operation | movement order of the jet stirring construction method by this invention.   FIG. 5 is a conceptual cross-sectional view showing a state of injection from the nozzle part of FIG. 4.   It is a conceptual diagram which shows the operation | movement order of the jet stirring construction method by this invention.   It is a conceptual diagram which shows the operation | movement order of the jet stirring construction method by this invention.   It is a longitudinal cross-sectional view which shows the monitor part of the jet stirring apparatus of the jet stirring method by other embodiment of this invention.   FIG. 10 is an enlarged view of the monitor unit of FIG. 10, (a) is a longitudinal sectional view, and (b) is a side view of (a).   The modification of the nozzle part of this invention is expanded and shown, (a) is a longitudinal cross-sectional view, (b) is a side view.   FIG. 13 is a conceptual cross-sectional view showing an injection state from the nozzle part of FIG. 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection stirrer 2 Drive device 3 Multi-tube rod 4 Feeding device 5 Monitor part 8 Ground 9 Compressed air and ultra-high pressure water 10 Discharged mud 11 Drilling hole 12 Ground improvement medium (hardening material) mainly composed of cement
13 Reactant 51, 52, 53, 54 Tube 61, 62, 71, 72 Injection nozzle (injection part)
71a, 72a Main injection nozzles 71b, 72b, 71c Auxiliary injection nozzle 81 Stirred ground 82 Pile

Claims (6)

A multi-pipe rod is fed into the ground, and the multi-pipe rod is pulled up from the ground while rotating, and a ground improvement medium mainly composed of cement is injected from the injection nozzle provided on the multi-pipe rod. In the method of improving the ground by injecting into the ground and agitating the ground to construct a pile with a predetermined diameter, the lower end of the above-mentioned multi-pipe rod is provided with upper and lower injection parts each provided with a nozzle, and a predetermined growth Within this range, water is jetted together with compressed air from the upper jet section to cut the ground improvement zone, and the waste mud is discharged to the ground through the cutting hole. Two injection parts consisting of an injection nozzle and surrounding injection nozzles are provided on both sides of the multi-tube rod at the same height from the tip, and in the region of the ground improvement zone, the injection nozzle at the center of the lower injection part From the cement mill The ground improvement medium composed mainly of ejects set to lower pressure than the injection pressure of the ground improvement medium composed mainly of cement milk reactants has a property to harden the cement milk from the surrounding of the injection nozzle Thus, immediately after jetting the ground improvement medium containing cement milk as a main component, a pile having a predetermined diameter is constructed by quickly curing the medium with the reactant.   In the area of the ground improvement area, water is sprayed together with compressed air from the upper stage injection nozzle to cut the ground, and after the lower stage injection section reaches the area of the ground improvement area, the lower injection section The jet stirring method according to claim 1, wherein the ground improvement medium is jetted from a central jet nozzle, and the reactant is jetted from surrounding jet nozzles.   The jet stirring method according to claim 1 or 2, wherein water glass-based sodium silicate is used as the reactant. A multi-pipe rod is fed into the ground, and the multi-pipe rod is pulled up from the ground while rotating, and a ground improvement medium mainly composed of cement is injected from the injection nozzle provided on the multi-pipe rod. In the jet agitating device that builds a pile of a predetermined diameter by injecting into the ground and constructing a pile with a predetermined diameter, the lower end of the multi-tube rod is provided with upper and lower injection parts, respectively, and compressed into the upper injection part an injection nozzle for injecting water with air provided, the injection nozzle of the center on the lower side injection unit, provided with two ejection portion comprising a periphery of the injection nozzle at the same height from the tip on both sides of the multi-tube rod, cement milk supply ground improvement medium mainly to the injection nozzle of said center, to the main component cement milk reactants has a property to harden the cement milk to the injection nozzle around the Injection stirring device is characterized in that so as to supply injected is set to a lower pressure than the injection pressure of the ground improvement medium.   6. The jet agitating apparatus according to claim 5, wherein the jet nozzles around the lower jet section are inclined to the central jet nozzle side.   6. The jet agitating apparatus according to claim 5, wherein the jet nozzles around the lower jet section are provided concentrically with the central jet nozzle.

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