JP3731669B2 - Ground improvement system and construction method - Google Patents

Description

  The present invention relates to a ground improvement system and a construction method, and more particularly, to a system and a construction method in which both a mechanical agitation method combined with jet agitation and an abrasive jet method are incorporated.

  Various ground improvement methods for soft ground such as soft clay soil and ground improvement systems used therefor are known. For example, there is a ground improvement method for forming a columnar solidified body by forming a hole in the target ground and injecting a hardening material such as cement milk into the formed hole and the surrounding ground.

  In this ground improvement method, a rod-shaped ground improvement tool is used for drilling holes and injecting a hardener into the target ground. And on the ground of the target ground, a ground improvement machine that drives forward and backward while rotating the rod-shaped ground improvement tool, a mixing device for sending water or hardened material etc. with increased pressure to the ground improvement tool, A plant device including a pump device is installed. In general, a rod-shaped ground improvement tool is a long swivel unit having a supply port for water or a hardened material pumped from a plant apparatus, and a long tube containing a pipe for transferring water or a hardened material from the swivel unit. It consists of a rod part (usually connecting a plurality of rods) and a monitor part having an injection port on the side surface and / or tip to inject water or a hardened material from the rod part.

  The monitor part of the ground improvement tool described in Patent Document 1 includes a side injection port of water or a hardened material and a stirring blade on its side surface, and pressure is applied from the side injection port during drilling that rotates forward. A hole is efficiently formed by jetting water to cut the surrounding ground and stirring the ground with a stirring blade. After forming a hole to a predetermined depth, a uniform solidified body is formed by spraying the hardened material from the side injection port while sufficiently rotating backward and sufficiently stirring the ground and the hardened material with a stirring blade. This is the so-called “jet stirring combined type mechanical stirring method”.

The monitor part of the ground improvement tool described in Patent Document 2 includes a tip injection port for injecting water containing an abrasive (hereinafter referred to as “water abrasive mixed material”) at the tip thereof, and rotating forward When drilling holes, it is possible to cut obstacles (such as rubble, concrete blocks, wooden piles, etc.) in the target ground by spraying the abrasive water mixture from the tip spray port. This is the so-called “Abrasive Jet Method”. The side surface of the monitor part of the ground improvement tool of the abrasive jet method can also be provided with a side injection port of the hardened material, and after forming the drilling hole, it solidifies by spraying the hardened material from the side injection port while rotating backwards Build your body.
JP 2000-17650 A JP 2001-49654 A

  In the mechanical agitation method combined with jet agitation described in Patent Document 1, if the object hits an obstacle in the target ground (such as rubble, concrete lump, steel plate, wooden pile, etc.) during drilling, the cutting performance is not sufficient, and further cutting is required. Can't continue the hole. In such a case, if a hole is unavoidably avoided by avoiding an obstacle, a solidified body cannot be formed at a planned location, and the number of solidified bodies may be insufficient. Also, if you want to use a completely different device to remove the obstacle, you must first remove the ground improvement machine and the plant device installed on the ground and install an obstacle removal device, and the work load It was large and construction was delayed.

  On the other hand, in the abrasive jet method of Patent Document 2, the cutting performance of the obstacle is extremely high, but the efficiency of forming a hole in the normal ground without the obstacle (such as the stirring performance of the ground) is compared with the mechanical stirring method using the jet stirring. Since it is inferior, the solid body of favorable quality may not be obtained in normal ground.

  In view of the above problems, the present invention incorporates the advantageous features of both the jet agitation combined mechanical agitation method and the abrasive jet method so that when there is no obstacle on the target ground, an efficient injection agitation combined type An object of the present invention is to provide a ground improvement system and a construction method that can be easily switched to an abrasive jet method when a mechanical stirring method is applied and an obstacle is hit.

In order to achieve the above object, the present invention provides the following system and method.
(1) The ground improvement system according to claim 1 is a system for performing a ground improvement work for forming a solidified body by forming a hole in the target ground and injecting a hardener into the hole. Have
The basic configuration includes (a) means for delivering water or a hardener at medium pressure, (b) means for delivering a water abrasive mixture at high pressure, and (c) a supply port for the water or hardener. A ground improvement tool comprising a swivel part, a rod part having a pipe for transferring the water or the hardened material, and a monitor part having a side injection port for jetting the water or the hardened material, and (d) the ground improvement tool. A ground improvement machine that can be attached and is driven forward or backward while rotating the ground improvement tool. Furthermore, (e) the ground improvement tool includes an injection machine agitation tool and an abrasive jet tool that are attached to the ground improvement machine so as to be interchangeable with each other during construction. Here, (f) the injection machine agitation tool further includes an agitating blade in the monitor unit, and (g) the abrasive jet tool has a tip injection port for injecting the water abrasive mixture to the monitor unit. Furthermore, it is characterized by comprising.

(2) The ground improvement construction method according to claim 2 is a construction method for forming a solidified body by forming a hole in the target ground and injecting a hardener into the hole, and has the following configuration.
First, a system used in this construction method is provided. That is, (a) a means for sending water or a hardened material at medium pressure, a means for sending a water abrasive mixed material at a high pressure, a swivel part comprising the water or hardener supply port, the water or A ground improvement tool comprising a rod portion having a pipe for transferring a hardened material and a monitor portion having a side injection port for injecting the water or the hardened material, and the ground improvement tool to which the ground improvement tool can be attached. A ground improvement machine that drives forward or backward while rotating, and includes a jet agitating tool and an abrasive jet tool that are interchangeably attached to the ground improvement machine during construction as the ground improvement tool The injection machine agitation tool further includes an agitating blade in the monitor unit, and the abrasive jet tool further exposes a tip injection port for injecting the water abrasive mixture to the monitor unit. A step of providing a ground improvement system comprising.
Using this system, (b) the injection machine agitating tool is attached to the ground improvement machine, and the water is injected from the side surface injection port with medium pressure and agitated by the agitating blade to form a hole in the target ground. And (c) replacing the injection machine agitation tool with the abrasive jet tool at a location where no hole can be drilled by the injection machine agitation tool; and (d) from the tip injection port of the abrasive jet tool. And forming a hole in the target ground while high-pressure jetting the water abrasive mixture.

  According to the present invention, since the ground improvement tool of the mechanical agitation method combined with the jet agitation method and the ground improvement tool of the abrasive jet method can be replaced during the construction, it is efficient when there is no obstacle on the target ground. If a mechanical agitation method combined with jet agitation is applied and an obstacle is hit, it can be easily switched to the abrasive jet method. Therefore, it is not necessary to remove the ground improvement machine or the plant device and install another device in order to remove the obstacle. As a result, a ground improvement system and method that combine the advantageous features of both methods will be realized, and construction will be continued only by exchanging the ground improvement tool without changing large equipment, even if any obstacles are encountered. Can do. As a result, the work load is reduced and the construction cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1A to FIG. 1F are diagrams schematically showing a construction example of a ground improvement method using a ground improvement system according to the present invention step by step. In the figure, the white arrow indicates the moving direction of the ground improvement tool (downward is forward, upward is backward). The target ground is, for example, soft viscous soil or sandy soil mixed with obstacles. As an example, the diameter of the solidified body to be created is 700 to 1600 mm, and the improved depth is 15 to 20 m.

  First, the ground improvement system of this invention is demonstrated roughly. FIG. 1A shows only a part of the system. The ground improvement system is a system for performing ground improvement work for forming a solidified body by forming a hole 91 in the target ground 90 and injecting a hardening material after the hole is formed. On the ground, a ground improvement machine 10 and a ground improvement plant apparatus (not shown here) shown in FIG. 2 to be described later are installed. The ground improvement plant apparatus (not shown) includes means for sending water or a hardened material at medium pressure and means for sending a water abrasive mixed material at high pressure. In the present invention, “intermediate pressure” and “high pressure” are relative expressions of the fluid pressure to be delivered or ejected, the range of “medium pressure” is 5 to 15 MPa, and the range of “high pressure” is 20 to 40 MPa. Range.

  The ground improvement machine 10 is, for example, a spindle ground improvement machine, to which a rod-like ground improvement tool can be attached, and can be driven forward or backward while rotating the ground improvement tool. In the present invention, the ground improvement tools include two types of ground improvement tools that are attached to the ground improvement machine 10 in the middle of the construction in an exchangeable manner. One is a ground improvement tool for a mechanical agitation method combined with jet agitation (referred to herein as “injection machine agitation tool” or “CMS tool”), and the other is a ground improvement tool for an abrasive jet method. Tool (referred to herein as an “Abrasive Jet Tool” or “QSJ Tool”).

  In FIG. 1A, the ground improvement tool attached to the ground improvement machine 10 is a CMS tool. The CMS tool includes a swivel portion (CMS swivel 20) having a supply port for water or a hardened material sent from a plant apparatus, and a rod portion (CMS rod) containing a pipe for transferring water or a hardened material sent from the swivel portion. 30), and a monitor unit (CMS monitor 40) having a side injection port 42 for injecting water or a hardened material sent from the rod unit, is connected along the tool rotation axis. A pair of stirring blades 41 further extend in opposite directions perpendicular to the tool rotation axis on the side surface of the CMS monitor 40. As an example, the diameter of the rod portion is 90 to 140 mm, and the diameter of the injection port is, for example, 2.1 to 3.4 mm.

  At the start of construction, such a CMS tool is attached to the ground improvement machine 10, while rotating forward, water 140 is sprayed from the side injection port 42 with medium pressure to cut the surrounding ground, and the stirring ground 41 is used to stir the surrounding ground. Drilling holes 91 are formed in the target ground 90. If it is a normal ground without obstacles (rubbing stone, concrete lump, iron plate, wood pile, etc.), the hole 91 will be formed without delay.

  FIG. 1A is a diagram at the time when excavation by the CMS tool is disabled. There are obstacles such as rubble in the target ground 90, and the tip of the CMS monitor 40 stops at this point. The CMS monitor 40 cannot cut such rubble 92 or the like.

  FIG. 1B is a diagram when the CMS tool is changed to the QSJ tool. The QSJ tool also has a swivel part (QSJ swivel 60) having a supply port for water or a hardener sent from the plant apparatus, and a rod part (for QSJ) containing a pipe for transferring the water or hardener sent from the swivel part. A rod 70) and a monitor unit (QSJ monitor 80) having a side injection port (not shown) for injecting water or a hardened material sent from the rod unit are connected along the tool rotation axis. The QSJ swivel 60 further includes a supply port for the water abrasive mixture, the QSJ rod 70 further incorporates a pipe for transferring the water abrasive mixture, and the QSJ monitor 80 further includes the water abrasive mixture. A tip injection port for injecting the material is provided. As an example, the diameter of the rod portion is 73 to 90 mm, and the diameter of the injection port is, for example, 2.1 to 3.4 mm.

  In order to change to the QSJ tool, the CMS tool is first retracted and pulled out, and the CMS tool is removed from the ground improvement machine 10 and replaced by attaching the QSJ tool. After attaching the QSJ tool as shown in FIG. 1B, the QSJ tool is inserted to the current deepest position of the drilling hole 91, and drilling with the QSJ tool is started.

  FIG. 1C is a view at the time when rubble drilling is performed by the QSJ tool. The water abrasive mixed material 181 is jetted at a high pressure from the tip jet port (first tip jet port) 81 of the QSJ monitor 80 to pulverize the rubble or the like 92 that is an obstacle. The abrasive is silica sand or garnet.

  FIG. 1D is a diagram at the time of performing normal excavation with the QSJ tool. When normal excavation is performed with the QSJ tool, water 182 is injected at a medium pressure in the traveling direction from the other tip jet port (second tip jet port) 82 of the QSJ monitor 80 while rotating forward, and the side jet port 83. A hole 91 is formed by jetting water 183 at a medium pressure. When the ground having a relatively large amount of rubble 92 is continuous as in this construction example, it is preferable to continue normal excavation with the QSJ tool in this way. And when it hits rubble 92 etc., as shown to FIG. 1C, it switches to the high pressure injection of the water abrasive | polishing agent mixed material from a 1st front-end | tip injection port, and the rubble etc. 92 is crushed.

  As another construction example, in the ground where the rubble etc. 92 exist only suddenly, the CMS tool is replaced with the QSJ tool only when it hits the rubble 92, etc. The excavation may be performed by exchanging with the CMS tool again. This is because the CMS tool is more efficient for normal excavation. In that case, after forming the hole, a solidified body is formed by a CMS tool, but the process is the same as the conventional jet stirring combined mechanical stirring method.

  FIG. 1E is a diagram at a time point when the formation of the hole by the QSJ tool is finished and the solidified body is created as it is by the QSJ tool. At the time of forming the solidified body, the medium 184 is injected with the curing material 184 from the side injection port 83 of the QSJ monitor 80 while rotating backward. The hardener 184 is preferably cement milk containing abrasive (hereinafter referred to as “cement milk abrasive mixture”). When the cement milk abrasive mixture 184 is mixed with the ground and solidified, it becomes a columnar solidified body 93.

  FIG. 1F is a diagram at the time when the formation of the solidified body 93 by the QSJ tool is completed.

  FIG. 2 is a diagram schematically showing the configuration of the ground improvement plant apparatus 100 included in the ground improvement system of the present invention. The abrasive jet plant apparatus 200 functions as a means for delivering a water abrasive mixed material at a high pressure, and the curing material plant apparatus 300 functions as a means for delivering water or a cured material at an intermediate pressure.

  The abrasive jet plant apparatus 200 of FIG. 2 uses a direct pressurization method, and includes an abrasive silo 201 storing abrasives (silica sand, garnet, etc.), a water tank 202 containing an abrasive mixing conduit, a high pressure And a high-pressure pump 203 such as an RC pump. The abrasive is fed from the abrasive silo 201 into the abrasive mixing conduit of the water tank 202. The water in the water tank 202 is supplied into the abrasive material mixing conduit, and the abrasive material and the water are mixed to produce a water abrasive material mixture. The water abrasive mixture is sent to the high-pressure pump 203 where it is pressurized and sent out in a high-pressure state. If the QSJ tool is connected, it is sent to the QSJ swivel.

  The hardening material plant apparatus 300 of FIG. 2 includes a cement silo 301 storing cement, an abrasive automatic weighing machine 303 capable of storing abrasives and measuring the supply amount thereof, a mixing plant apparatus 304, a water supply tank 305, And a grout pump 306. The mixing plant apparatus 304 has an appropriate blending amount of cement from the cement silo 301 via the weighing machine 302, an abrasive (silica sand, garnet, etc.) from the automatic abrasive weighing machine 303, and water from the water supply tank. Supplied in. The mixing plant 304 includes a mixer 304a that mixes each material and an agitator 304b that is sufficiently stirred to form a slurry. In this way, a cement milk abrasive mixture is produced. The cement milk abrasive material mixture is sent to the grout pump 306, where it is pressurized and delivered in an intermediate pressure state. The cement milk abrasive material mixture is sent to the CMS swivel when the CMS tool is connected, and is sent to the QSJ swivel when the QSJ tool is connected.

  From the hardened material plant apparatus 300, it is also possible to send water in an intermediate pressure state. In that case, water is sent from the water supply tank 305 to the grout pump 306, where it is pressurized and sent out in an intermediate pressure state. Water is sent to the swivel for CMS when the CMS tool is connected, and is sent to the swivel for QSJ when the QSJ tool is connected.

  FIG. 3 is a partial perspective view showing an embodiment of the CMS tool of the present invention. A CMS monitor 40 is connected to the CMS rod 30. On the side surface of the CMS monitor 40, a side surface injection port 42 through which water 140 or a hardened material is injected at an intermediate pressure is provided. In the example shown in the drawing, a pair of side surface injection ports 42 are provided in the opposite direction with respect to the tool rotation axis, one above each below the stirring blade 41. As an example, a nozzle may be provided so as to inject in a direction inclined up and down as shown. The number, position, and injection direction of the side injection ports 42 are optimally provided in consideration of the ground cutting function and the hardened material injection stirring function. Each of the pair of stirring blades 41 is provided with a plurality of excavation bits on the rotation direction side thereof, and has a ground excavation function in addition to the agitation function. More preferably, the excavation bit 43 is provided at the tip of the CMS monitor 40.

  FIG. 4 is a partial perspective view showing an embodiment of the QSJ tool of the present invention. A QSJ monitor 80 is connected to the QSJ rod 70. At the tip of the QSJ monitor 80, a first tip jet port 81 for jetting the water abrasive mixture 181 at a high pressure and a second tip jet port 82 for jetting water 182 at an intermediate pressure are provided. Furthermore, a side injection port 83 for injecting the curing material 183 at an intermediate pressure is provided on the side of the QSJ monitor 80.

  FIG. 5 is a cross-sectional view showing an example of the swivel portion of the QSJ tool of the present invention, that is, the QSJ swivel 60. The example shown is a three-hole tube swivel. For example, the supply port 61a of the water abrasive mixture from the abrasive jet plant apparatus of FIG. 2 and the transfer pipe 61 communicating therewith, and the water supply port 62a of the hardener plant apparatus of FIG. 2 and the transfer communicating therewith A pipe 62, a supply port 63a for water or cement milk abrasive mixed material from the hardener plant apparatus, and a transfer pipe 63 communicating therewith are incorporated. The swivel is provided as a connection for enabling fluid to be supplied to the rotating ground improvement tool.

  6 is a cross-sectional view showing an example of the rod portion of the QSJ tool of the present invention, that is, the QSJ rod 70 connected to the QSJ swivel of FIG. 6 is a three-hole tube rod connected to the three-hole tube swivel of FIG. 5. Transfer pipes 71, 72, and 73 communicating with the transfer pipes 61, 62, and 63 of the QSJ swivel in FIG. 5 are incorporated. These transfer pipes 71, 72, and 73 communicate with the first tip injection port 81, the second tip injection port 82, and the side injection port 83 of the QSJ monitor of FIG.

It is the figure which showed schematically the construction example of the ground improvement construction method using the ground improvement system by this invention step by step, and is the figure at the time of the excavation impossible with a CMS tool. It is the figure which showed the construction example of the ground improvement construction method using the ground improvement system by this invention step by step schematically, and is the figure at the time of changing the CMS tool to the QSJ tool. It is the figure which showed the construction example of the ground improvement construction method using the ground improvement system by this invention step by step, and is the figure at the time of performing the rubble drilling with the QSJ tool. It is the figure which showed the construction example of the ground improvement construction method using the ground improvement system by this invention step by step, and is the figure at the time of performing normal excavation with a QSJ tool. It is the figure which showed the construction example of the ground improvement construction method using the ground improvement system by this invention step by step schematically, and is the figure at the time of performing the solidified body creation with a QSJ tool. It is the figure which showed the construction example of the ground improvement construction method using the ground improvement system by this invention step by step schematically, and is the figure at the time of the solidification body formation by a QSJ tool being completed. It is a figure which shows roughly the structure of the ground improvement plant apparatus contained in the ground improvement system of this invention. It is a fragmentary perspective view which shows one Example of the CMS tool of this invention. It is a fragmentary perspective view which shows one Example of the QSJ tool of this invention. It is sectional drawing which shows an example of the swivel part of the QSJ tool of this invention. It is sectional drawing which shows an example of the rod part of the QSJ tool of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ground improvement machine 20 CMS swivel 30 CMS rod 40 CMS monitor 41 Stirring blade 42 Side injection port 60 QSJ swivel 61, 62, 63 Supply port 70 QSJ rod 80 QSJ monitor 81 First tip injection port 82 1st 2 tip injection port 83 Side injection port 90 Target ground 91 Drilling hole 92 Rubble, etc. 93 Solidified body 100 Ground improvement plant device 140 Water (medium pressure injection)
181 Silica sand mixed material (high pressure injection)
182 Water (Medium pressure injection)
183 Water (Medium pressure injection)
184 Cement Milk Silica Sand Mixture (Medium Pressure Injection)
DESCRIPTION OF SYMBOLS 200 Abrasive jet plant apparatus 201 Abrasive material silo 202 Water tank 203 High pressure pump 300 Hardening material plant apparatus 301 Cement silo 302 Weighing machine 303 Abrasive material automatic weighing machine 304 Mixing plant apparatus 304a Mixer 304b Agitator 305 Feed water tank 306 Grout pump

Claims (2)

In the ground improvement system for performing ground improvement work to form a solidified body by forming a hole in the target ground and injecting a hardener into the hole,
(A) means for delivering water or hardener at medium pressure;
(B) means for delivering the water abrasive mixture at high pressure;
(C) From a swivel part provided with the water or hardener supply port, a rod part provided with a pipe for transferring the water or hardener, and a monitor part provided with a side jet port for jetting the water or hardener. A ground improvement tool
(D) a ground improvement machine to which the ground improvement tool can be attached and which drives forward or backward while rotating the ground improvement tool;
(E) As the ground improvement tool, including an injection machine agitation tool and an abrasive jet tool that are attached to the ground improvement machine in an exchangeable manner during construction,
(F) The injection machine stirring tool further includes a stirring blade in the monitor unit,
(G) The abrasive jet tool further includes a tip injection port for injecting the water abrasive mixed material to the monitor unit. In the ground improvement method of forming a solidified body by forming a hole in the target ground and injecting a hardener into the hole,
(A) Means for delivering water or hardened material at medium pressure, means for delivering water abrasive mixed material at high pressure, swivel part comprising the water or hardener supply port, the water or hardener A ground improvement tool comprising a rod portion having a pipe for transferring water and a monitor portion having a side injection port for injecting the water or the hardened material, and the ground improvement tool can be attached and rotated. A ground improvement machine that is driven forward or backward while being driven, and includes an injection machine agitating tool and an abrasive jet tool that are attached to the ground improvement machine interchangeably during construction as the ground improvement tool, The injection machine agitation tool further includes an agitating blade in the monitor unit, and the abrasive jet tool further includes a tip injection port for injecting the water abrasive mixture to the monitor unit. Comprising the steps of: providing a board improvement system,
(B) attaching the injection machine agitation tool to the ground improvement machine, forming a hole in the target ground while agitating with the agitating blade while injecting the water at an intermediate pressure from the side surface injection port;
(C) replacing the jetting machine agitation tool with the abrasive jet tool at a location where no hole can be drilled by the jetting machine agitation tool;
(D) forming a hole in the target ground while high-pressure jetting the water abrasive mixed material from the tip jet port of the abrasive jet tool.

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