JP5421206B2 - Ground improvement method and equipment - Google Patents

Description

  The present invention relates to a ground improvement method and an apparatus therefor, in which a hardened material is jetted onto a target ground at a high pressure for the purpose of improving a soft ground or a structure foundation, and a hardened material layer is created in the ground.

  Conventionally, with regard to hard material injection for hard material layer construction for the purpose of improving soft ground or building foundations, high pressure jet agitation and injection rod that stir and mix the target ground with the injected hard material jet itself There is mechanical agitation in which the target ground is agitated and mixed by an agitating blade that overhangs.

  In high-pressure jet agitation, in order to create a large-diameter hardened material layer by extending the reach distance as much as possible, various measures such as ejecting excess slime using the air lift effect at the same time are injected. In addition, a method (for example, see Patent Document 1) has been developed in which a curing material jet is protected with air by using a polymerization injection nozzle including a core nozzle and an annular nozzle surrounding the core nozzle to protect and extend the reach distance. Yes.

For mechanical stirring, a hardener injection nozzle is further set at the tip or side of the stirring blade to extend the reach of the hardener jet and to make the surrounding soil and hardener more homogeneously stirred (for example, Patent Document 2). In order to prevent the jet flow from the injection nozzle of the injection rod from diffusing at the tip, a diffusion prevention plate that blocks the path of the hardened material that is injected at high pressure from the injection nozzle of the injection rod at the tip of the stirring blade Means for setting (see, for example, Patent Document 3) have also been taken.
Japanese Examined Patent Publication No. 7-100931 JP 50-107714 A JP 2000-17650 A

However, no method has been established for reliably producing a hardened material layer having the strength and size suitable for the purpose as designed. Furthermore, the conventional ground improvement by stirring and mixing of the ground by stirring blade and hardening material injection, when the injection nozzle is provided at the base of the stirring blade, if the air injection is not used together, the hardening material jet reaches the tip of the stirring blade do not do.
Therefore, when a method using air injection is employed, there is a problem that the slime is discharged more than necessary due to the air lift effect by the air injection, and there is a lot of waste in the injection material, and it is easy to lead to ground deformation such as ground subsidence.

  In addition, for mechanical stirring with a stirring blade, there is a problem that large torque is required to rotate the injection rod, leading to an increase in the size of the device, and since the injection from the nozzle set on the stirring blade does not use air injection together, Since the injection energy is attenuated and attenuated, the reach of the high-pressure jet cannot be increased, so that the torque reduction effect cannot be exchanged and the stirring effect cannot be obtained. .

  Also, when the injection rod is driven in the ground without injecting the injection nozzle, such as when the injection rod is penetrated from the ground surface to the depth of improvement body formation (empty digging portion), the surrounding soil enters the nozzle hole. There is a problem that causes nozzle clogging and backflow of earth and sand to the nozzle, and even when the injection operation does not work, measures are taken to prevent this by blowing out drilling water etc. from the nozzle. There was a problem that had to be consumed in vain.

  Furthermore, in the conventional high-pressure injection method, since there was no means for confirming whether the jet of the hardened material or the like reached a predetermined range, it took a lot of excavation time and injection time depending on the experience value. There is a possibility that a phenomenon such as a ground uplift may occur due to an unnatural load, so that a large amount of injection material is required, which is a great burden in terms of cost.

  In order to solve the above problem, the present invention sets the large and small stirring blades in two upper and lower stages, attaches a shielding sensing plate equipped with a data transmission sensor to the tip of the upper stirring blade, and lower stirring At the tip of the blade, an injection nozzle is provided in which the jet to be jetted strikes the shielding sensing plate of the upper stirrer blade, and the jet of the hardening material or the like is detected by the jet data from the jet nozzle to the sensing plate of the jet. It was configured to confirm that the position had been reached and to understand the magnitude of the jet energy at that time.

Furthermore, an injection nozzle that injects upward in a range where the jet impinges on the lower end of the tip of the lower stirrer blade is provided on the rod wall surface within 20 cm below the lower stirrer blade, and the ground cutting jet has two stages. Thus, even a jet with a short cutting distance (compact jet) that does not use air injection can be cut with a large diameter, and torque reduction and uniform filling (stirring effect) can be obtained.
In addition, by exchanging the torque reduction effect, it was possible to reduce the size of construction machines, and it was also possible to deal with hard ground.

  In addition, depending on the construction environment, an auger blade was provided on the upper part of the upper stirrer blade and an auger blade on the outer peripheral wall of the rod immediately above the agitator blade, thereby reducing excess pore water pressure and discharging excess slime. In other words, the reach of the improved jet flow from the lower stirrer blade nozzle and the magnitude of the jet energy are confirmed by the shielding sensing plate of the upper stirrer blade, and the rotational speed and pull-up speed of the injection rod are adjusted to meet the purpose. It was made possible to create a hardened material layer with high strength and size.

  In addition, an agitator blade is installed at the top of the upper stirrer blade, and an auger blade is installed directly above it, to reduce excess pore water pressure and discharge excess slime, and to discharge excess ground pressure due to the excess slime to the ground. It is possible to construct a ground improvement layer with high mixing efficiency and excavation efficiency while maintaining a high packing density.

  Further, a nozzle plug constituted by an elastic member along the shape of the nozzle hole of the injection nozzle is fitted and closed in the nozzle hole, and the nozzle plug is blown off by the injection pressure of the injection material when performing the injection operation. The pop-out pressure was adjusted by adjusting the length of the part where the nozzle plug fits the shape of the nozzle hole and the length of the fitting length.

  The ground improvement device according to the present invention is limited to the outer diameter of the upper stirrer blade by the shielding sensing plate attached to the tip of the upper stirrer blade. Corresponding to this, there is a problem that cannot be improved closely, and in response to this, an injection nozzle that injects in the extending direction is provided at the tip of the upper stirrer blade, and the shield sensor plate moves the cured material jet of the lower stirrer blade to the shield sensor plate position. While confirming the reaching state, the high pressure injection of the hardened material was performed from the tip nozzle of the upper stirring blade, thereby improving the adhesion with the underground structure with a limited improvement range.

  Since the present invention is configured as described above, it is possible to manage the rotation, lowering and raising of the injection rod based on the transmission data from the shielding sensing plate, and more excavation time and injection time based on experience values in the conventional injection method. It was possible to eliminate the waste of the injection material due to the application of the material, and to avoid the unnatural load applied to the ground.

  Furthermore, since a means for confirming whether or not the jet of hardened material has reached a predetermined range is obtained, it is possible to avoid a load due to over-injection, so that phenomena such as ground uplift can be avoided, and the injection material is also saved accordingly. Because it can be done, it has the effect of bringing about significant benefits in terms of cost.

The side view of the injection | rod rod end part which shows the Example of this invention and shows the principal part structure of an injection | pouring rod roughly from an exterior surface Similarly, a vertical cross-sectional side view of the tip of the injection rod schematically showing the flow path in the rod in the basic form in which the injection in the extension direction of the tip of the upper stirring blade is not performed in the injection rod of FIG. Similarly, a side view of the tip of the injection rod schematically showing the structure of the main part of the injection rod in which an agitator blade is further provided on the upper part of the upper stirring blade and an auger blade is provided on the outer circumferential wall of the rod immediately above it. Similarly, in the injection rod of FIG. 3, the longitudinal cross-sectional side view of the tip of the injection rod schematically showing the flow path in the rod in the form in which the flow path to each injection nozzle is branched with a single flow path in the rod. Similarly, the injection rod shown in FIG. 3 has two flow paths in the rod, an injection material supply channel to the extension direction injection nozzle at the tip of the upper stirring blade, and an injection material supply flow to the lower stirring blade tip nozzle and the lower horizontal injection nozzle. Longitudinal cross-sectional side view of the tip of the injection rod schematically showing the flow path in the rod in a form in which the path is separated Similarly, side view of the entire device showing the construction status Similarly, a parallel hardened material layer that compares the injection area of the hardened material layer that has been injected by setting an injection nozzle in the extension direction at the tip of the upper stirring blade and the hardened material layer that has been injected without setting the extended direction injection nozzle. Cross sectional plan view of Similarly, the longitudinal cross-sectional side view of the injection nozzle in the state which mounted | wore with the nozzle plug which shows the state which mounted | wore the nozzle plug with the nozzle plug

  Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes an injection rod, which has two large and small stirring blades projecting on both sides of the flank. A load meter, a microphone, etc. are built into each tip of the upper stirring blade B, and has a data transmission function using electrical signals. Shield sensing plates 8 and 8 are provided, and at each tip of the lower stirring blade C, an injection nozzle 3 is provided, in which the jet 6 to be sprayed strikes the shielding sensing plates 8 and 8 of the upper stirring blade B. Confirmation that the jet of hardened material or the like has reached the position of the sensing plate 8 based on the impact data of the jet 6 from the injection nozzle 3 pumped from the material tank through the flow path R to the sensing plate 8, and at that time The magnitude of the jet energy at can be grasped.

  In the lower part of the lower stirring blade C, a jet is directed upward in a range in which the jet impinges on the lower end of the lower stirring blade C at the lower end wall surface at a distance of about 10 to 20 cm from the lower stirring blade C. Jet nozzles 4 and 4 are provided, and a jet 7 is jetted along the extending direction of the lower stirring blade C, and the jet impinges on the lower end of the tip of the lower stirring blade C. The jet blanks from 4 and 4 fill the lower part of the lower stirring blade C and the injection blank outside the tip.

  In addition, the nozzle hole of the injection nozzle set in the injection rod 1 and the stirring blade is detachably fitted with a nozzle plug P made of an elastic member as shown in FIG. The nozzle hole is closed by the nozzle plug P, and is pushed out by the injection pressure at the start of the injection operation.

The injection rod 1 configured as described above communicates with the nozzles 3 and 4 around a flow path R communicating with an injection material tank via a swivel 11, and injects the injection material as a high-pressure jet according to the operation. In addition, the small machine 12 based on the backhoe is provided with a driving operation such as rotation and vertical movement by the management data collected in the management aggregation mechanism.
In addition, a plunger pump, a pressure gauge, and a flow meter for measuring and adjusting the injection pressure and discharge amount of the hardener and the like are set in the communication flow path between the injection material tank and the core flow path. By selecting the nozzle tip N, the aperture can be adjusted for expansion / contraction.

  An injection nozzle that does not perform injection operation using a small machine based on a backhoe of 0.8 to 1.4 cubic rice class, with an N value of 30 or less for sandy soil and an N value of 10 or less for viscous soil. The injection rod 1 whose nozzle hole is blocked by the nozzle plug P is supplied with fresh water if necessary, and is injected to the target ground from the nozzles 2 and 3 while rotating the injection rod 1 at a lowering speed of 2 minutes / m. Then, the excavation claw Ca set on the lower side of the tip bit D and the lower stirring blade C and the excavation claw Ca set on the lower side of the stirring blade A are inserted into the target ground G to the improved depth.

  The nozzle plug P is formed in a funnel shape in accordance with the space shape of the nozzle hole Nb formed in the nozzle tip N screwed and fixed to each injection nozzle setting part and the tapered surface Nc of the rear part. By adjusting the length (fit length) of the portion corresponding to the tapered surface Nc by increasing or decreasing the length, the popping pressure can be adjusted, and various types can be prepared. The discharge amount is adjusted according to the diameter of the injection port Nb of the nozzle tip N.

  At the time of excavation to the improved depth, the hardening material is supplied to the injection rod 1 and the injection pressure of the injection material to the injection nozzle is increased, so that the nozzle plug P is blown off together with the high-pressure jet and removed, and the injection pressure is 20 Mpa or higher. As a result of jetting the discharge amount of the injection nozzle 3 at 300 liters per minute and the discharge amount from the injection nozzle 4 at 100 liters per minute with the blade length of the stirring blade C of 1 m and the blade length of the upper stage stirring blade B of 2 m, the diameter is 2 m, uniaxial A cured material layer having a compressive strength of 1 to 3 Mpa could be formed.

  That is, the cutting area of the A1 portion of FIG. 2 by the lower stirring blade C of 1 m blade length is 0.785 square meters, and the cutting area of the A2 portion of FIG. 2 by the upper stirring blade B and stirring blade A of 2 m blade length is 2. The discharge amount when jetted in the same time is 355 square meters, and the discharge amount of the nozzle 2 corresponding to the upper stirring blade B and the stirring blade A is 3 with respect to the discharge amount 1 of the nozzle 3 corresponding to the lower stirring blade C. It becomes the ratio.

  When the injection rod 1 penetrates and descends into the target ground as described above and reaches the improved depth, the hardening material is pumped to the injection nozzle and injected from the injection nozzles 3, 3 and 4, 4 as excavation jets, respectively. However, the discharge amount is adjusted by adjusting the diameter of each nozzle injection hole so that the discharge amount from the injection nozzle 3 is 300 liters per minute and the discharge amount from the injection nozzle 4 is 100 liters per minute.

  In this way, by adjusting the discharge amount of each jet jet fluid in the upper and lower two stages according to the improved shared area ratio of each jet, it is possible to use an appropriate amount of the injection material at an appropriate part, and to save material significantly The jets 6 and 6 from the injection nozzle 3 impinge on the shielding sensing plates 8 and 8 at the tip of the upper stirring blade B, and from the load cells, sound collectors and the like installed on the shielding sensing plates 8 and 8. The arrival of the jet jet at the tip of the upper agitating blade B and the impingement energy are confirmed by the electric signal, and the elevating speed of the injection rod 1 is adjusted along this, so that the construction efficiency is greatly improved.

  As described above, the injection rod 1 is propelled and inserted into the target ground, and when the improved depth is reached, the hardener is injected, and the shield sensing plates 8 and 8 inject along the arrival of the hardener jet and the confirmation of the impact energy. Although the hardening material injection layer is formed while adjusting the ascending / descending speed of the rod 1, the injection material is supplied from the injection material tank to the injection nozzle 2 and the injection nozzles 3 and 4 as shown in FIG. If it is branched from the flow path of the book, it becomes easy to calculate the discharge amount and the like, but attenuation of the pumping energy at the tip is unavoidable.

  Therefore, as shown in FIG. 5, the rod is formed into a double pipe to form two flow paths R1 and R2, and the flow path R2 is injected into the injection nozzle 2 and the flow path R1 is injected into the injection nozzles 3 and 4. If the material is supplied, the jet flow can be made efficient by using the pumping energy as a separate system. Furthermore, since the construction method according to the present invention eliminates the air lift effect and saves the spray material and increases the efficiency of the construction, it is necessary to cope with the discharge of slime generated when the hardener is injected depending on the construction environment.

  As a countermeasure for the slime discharge, the stirring blade A is stretched over the upper stirring blade B, and the auger blade 9 is provided immediately above the stirring blade A, so that it is pushed up by the ground compaction by the hardening material injection when the injection rod 1 is raised. The surplus slime is crushed by the stirring blade A and discharged to the ground by the auger blade 9.

  Further, the shielding sensing plates 8 and 8 are configured so that the shape of the plate guides the direction of the jet 6 in the concentration direction to prevent diffusion at the tip of the jets 6 and 6 from the injection nozzle 3 to concentrate energy. In addition, it is possible to have a function of keeping the concentration of the hardener (mixing amount) constant.

  In the present invention, since the shielding sensing plates 8 and 8 are set at the tip of the upper stirring blade B, the jets 6 and 6 from the injection nozzle 3 may extend the reach distance beyond the length of the upper stirring blade B. Can not. Therefore, it is impossible to create a hardener injection layer that is in close contact with the wall surface of the underground structure.

  In Example 4, in response to the above problem, the injection nozzle 2 is provided at the tip of the upper agitating blade B, and the agitating blade A is set at the upper portion thereof. The injection rod 1 is inserted at a distance, and high pressure injection from the injection nozzles 3, 3 provided on the lower stirring blade C is performed by the shielding sensing plates 8, 8 attached to the tip of the upper stirring blade B. By confirming, the reach of the high-pressure jet from the injection nozzle 2 of the upper stirring blade B is grasped, and the improvement range is limited by performing high-pressure injection of the hardened material from the tip of the upper stirring blade. It was possible to improve the adhesion.

  Furthermore, by performing high-pressure injection of the hardened material from the upper stirring blade tip nozzle 2, it was possible to improve 100% which was impossible with mechanical stirring. In addition, a hardened material layer that adheres to the wall of the underground structure is formed on the outside of the hardened material layer by high-pressure jetting of the injection nozzles 3 and 4 and mechanical stirring. Compared to the case, the construction efficiency is remarkably good and the waste of the injection material can be greatly reduced, which is extremely advantageous.

  Since the present invention is configured as described above, the reach of the improved jet flow from the lower stirrer blade nozzle and the magnitude of the jet energy are confirmed by a small base machine with relatively low torque, and the rotational speed and pulling up of the injection rod are increased. By adjusting the speed, it is possible to create a hardened material layer with the strength and size according to the purpose, eliminating waste of the injection material, and increasing the elevating speed of the injection rod to greatly improve the construction efficiency. Has high utility value in industry.

DESCRIPTION OF SYMBOLS 1 Injection rod 11 Swivel 12 Small machine 2 Injection nozzle of the upper stage stirring blade tip 3 Injection nozzle of the lower stage stirring blade tip 4 Injection nozzle of the lower stage stirring blade lower part 5 Jet flow from the injection nozzle of the upper stage stirring blade tip 6 Injection of the lower stage stirring blade tip Jet from nozzle 7 Jet from jet nozzle below lower stirring blade 8 Shielding sensing plate 9 Auger blade A Stirring blade above upper stirring blade B Upper stirring blade C Lower stirring blade Ca Drilling claw D Injection rod tip bit G Target ground N Nozzle Tip Na Nozzle Tip Nozzle Hole Nb Nozzle Tip Injection Hole Nc Taper Surface of Nozzle Hole P Nozzle Plug X Construction Area by High Pressure Injection and Mechanical Stirring Y Construction Area by High Pressure Injection

Claims (7)

The upper stirrer blade provided with an injection nozzle at the front end of the upper stirrer blade having a shield sensing plate provided with a sensor for transmitting a signal to the management aggregation mechanism at the front end. Shorter lower stirring blades, injection rods each provided with an injection nozzle that injects upward in a range in which the jet impinges on the lower end of the tip of the lower stirring blades on the rod wall surface within 20 cm below the lower stirring blades, The hardened material is injected into the target ground while high-pressure jetting the jetting nozzle from the jet nozzle, and the hardener is jetted while controlling the rotation, lowering and raising of the injection rod according to the transmission data from the shielding sensing plate. Ground improvement method An upper agitating blade is provided above the upper agitating blade, and an injection rod provided with an auger vane on the outer wall of the rod immediately above the upper agitating blade is allowed to penetrate the target ground while high-pressure jetting of the hardener from each injection nozzle. While stirring the excess slime with the agitating blade provided on the upper part of the agitator and transporting it upward with the auger blade, the consolidation data of the surrounding soil is confirmed by the transmission data from the shielding sensing plate, and the rotation, lowering and raising of the injection rod are confirmed. The ground improvement method according to claim 1, wherein the curing material is sprayed while controlling the soil. An injection nozzle that injects in the extension direction is provided at the tip of the upper stirrer blade, an injection rod is inserted at a predetermined distance from the wall surface of the underground structure, and the lower stirrer blade tip nozzle is determined by the transmission data from the shielding sensing plate. The upper stirrer blade is used to confirm the arrival of the jet flow from the nozzle to the position of the shielding sensing plate and to inject high pressure from the nozzle provided at the tip of the upper stirrer blade while controlling the discharge amount and the cutting distance according to the transmission data. The ground improvement construction method according to claim 1 or 2, wherein an improved body in close contact with the wall surface of the underground structure is created outside the tip of the ground. When the injection rod is driven in the ground without injecting the injection nozzle, such as when the injection rod penetrates from the ground surface to the improved body formation depth, it is constituted by an elastic member along the shape of the nozzle hole of the injection nozzle. The nozzle plug is fitted and closed in the nozzle hole, and the nozzle plug is blown off and removed by the injection pressure of the injection material when performing the injection operation. Ground improvement method The upper stirrer blade provided with an injection nozzle at the front end of the upper stirrer blade having a shield sensing plate provided with a sensor for transmitting a signal to the management aggregation mechanism at the front end. Shorter lower stirring blade, injection rod provided with an injection nozzle for injecting upward in a range where the jet impinges on the lower end of the tip of the lower stirring blade on the rod wall within 20 cm below the lower stirring blade Ground improvement device The ground improvement device according to claim 5, wherein a stirring blade is further provided above the upper stirring blade, and an auger blade is provided on the outer circumferential wall of the rod immediately above the stirring blade. The ground improvement device according to claim 5 or 6, wherein an injection nozzle for injecting in an extending direction is set at a tip of the upper stirring blade.

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