JP4174443B2 - Spray cutting type ground injection method - Google Patents

Description

  The present invention relates to an improvement of a ground injection method, and more particularly, to a spray cutting type ground injection method for injecting a geological improvement injection material into the ground after spraying a high-pressure fluid to cut the ground at a predetermined depth. .

  A structure or a building transmits a load from above to the ground by a foundation structure built in the upper part of the ground or in the ground. However, when the ground is soft, etc., it is necessary to improve the ground sediment itself to enhance the bearing capacity, prevent settlement, reduce water permeability (improve water stoppage), and the like. The construction method used for this purpose is called the ground improvement construction method. One of the ground improvement methods is “ground injection method”.

  In the ground injection method, although not shown, a hole (hereinafter referred to as “ground hole”) is first formed by drilling a hole from the ground surface into the ground. Thereafter, a tubular member (hereinafter referred to as “injection tube”) is inserted into the ground hole. The injection tube is provided with an opening (hereinafter referred to as “injection port”) at a lower end portion or a side portion thereof.

  Next, on the ground side, a geological improvement injection material is generated. The injection material for geological improvement is in a liquid state immediately after generation, but is a substance that loses fluidity due to a chemical reaction and consolidates soil particles. As this geological improvement injection material, for example, cement milk or the like is used. Cement milk is obtained by adding water to cement to form a sol (a colloidal particle dispersed in a dispersion medium into a liquid state), and is also called a cement suspension. Cement milk has the property that the cement hydrate hardens and solidifies over time as the hydration reaction of the cement proceeds (hereinafter referred to as “self-curing over time”). For this reason, after a certain period of time, the hardened cement hydrate solidifies the soil particles.

Moreover, as another geological improvement injection material, for example, a water glass type injection material is used. Water glass-based injection material is a sol solution of sodium silicate (mixture of silicic acid (SiO ₂₎ and alkali (Na ₂ O)) was used as a main component, the addition of liquid called curing agent thereto, dehydration, polymerization As a result, a silicic acid (SiO ₂ ) is separated as a gel (the colloidal particles lose their fluidity due to interaction and become solidified). The separated and gelled silicic acid has adhesive strength, and consolidates the ground and exerts water-stopper on the ground. In the case of this type of water glass-based injection material, the time from gelation to gelation is referred to as “gel time”.

In addition, there are various types of injection materials for improving the geology such as silica-based and polymer-based materials, and an appropriate one is selected depending on the geology, construction conditions, and the like. In addition, the geological improvement injecting material may be in the form of a solution in addition to the colloidal form. This solution includes an aqueous solution using water (H ₂ O) as a solvent and an organic solution using an organic solvent.

  The geological improvement injection material generated in the above-mentioned injection material generation plant (not shown) on the ground side is in a liquid state immediately after the generation, and a delivery pump (not shown) etc. (Not shown) and sent from the delivery pump through a hose (not shown) and the like into the injection tube from the upper end of the injection tube. Thereafter, the geological improvement injection material is discharged to the outside (ground hole) from an injection port provided at the lower end or side of the injection tube. Since the injection material for geological improvement is pressurized by the delivery pump, it is further permeated or pushed into the ground within the ground through the gap between the soil particles in the hole wall of the ground hole. Thereby, after the injection material for geological improvement is inject | poured into the clearance gap between the soil particles inside a ground, it solidifies (gels), and the property of the ground is improved. (See Patent Document 1).

However, in the conventional ground injection method, as shown in FIG. 5, the ground hole 202 is drilled into the ground 201, the injection pipe 220 is inserted, and the bottom of the ground hole 202 is inserted using the injection holes 220a1, 220a2, etc. Even if the geological improvement injection material G is infiltrated into the ground 201 stepwise from the top to the top, even if it is solidified, the value of the permeability coefficient of the target ground and its non-uniformity, the injection for geological improvement Due to various factors such as the viscosity of the material and the actual gel time, a region (hereinafter referred to as an “unmodified region”) that remains without being improved as shown by reference numerals N11 to N14 in FIG. May end up. If such a situation occurs, it will cause problems such as insufficient ground support capacity of the structure to be constructed thereafter and insufficient water stop performance.
JP 2003-213664 A

  The present invention has been made to solve the above problems, and the problem to be solved by the present invention is a ground injection method capable of forming a geological improvement region in the ground around the ground hole with almost no gap. Is to provide.

In order to solve the above-mentioned problem, the injection cutting type ground injection method according to claim 1 of the present invention is:
After drilling the ground downward by the drilling means and the lift drive means to form a ground hole and reach a predetermined first underground depth position,
An injection pipe having an injection hole in the lower part and having a nozzle hole formed in the lower side is inserted into the ground hole until the lower end reaches the first underground depth position, and high-pressure fluid supply means is provided in the injection pipe. The high pressure fluid is ejected from the nozzle hole toward the side ground, and the injection pipe is rotated by a rotation driving means to cut the ground around the first underground depth position of the ground hole. Forming a disk-shaped injection gap,
Next, after drilling the ground further from the bottom of the ground hole by the drilling means and the lift drive means to dig up the ground hole and reach a predetermined second underground depth position, the lower end of the injection pipe is The ground hole is lowered by the elevating driving means until the second underground depth position is reached, the high pressure fluid supply means ejects the high pressure fluid from the nozzle hole toward the side ground, and the injection pipe is Rotating by a rotation driving means, cutting the ground around the second underground depth position of the ground hole to form a substantially disc-shaped injection gap,
In the same manner, the ground around the various medium depth positions up to the predetermined nth underground depth position is cut with the high-pressure fluid to form a substantially disc-shaped injection void for each medium depth position,
Next, an injection material supply means is connected to the injection tube in a state where the lower end of the injection tube is at the lowermost nth underground depth position, the geological improvement injection material flows out from the injection hole, and the injection hole passes through the injection gap. The first geological improvement region is formed by solidifying after injecting the geological improvement injection material into the ground around the nth underground depth position,
Next, after the lower end of the injection pipe is pulled up to the (n-1) underground depth position one step above, the injection material supply means causes the injection material for geological improvement to flow out from the injection hole, and the first through the injection gap. (N-1) After infiltrating the geological improvement injection material in the ground around the underground depth position and substantially in contact with the first geological improvement region or overlapping the first geological improvement region Solidify to form the second geological improvement zone,
In the same manner, in the ground around each middle depth position up to the first underground depth position, the ground substantially touches the adjacent geological improvement region immediately below or overlaps with the adjacent geological improvement region immediately below. A geological improvement region solidified after infiltrating the geological improvement injection material through the injection gap in the middle region is formed for each mid-depth position of each region.

Moreover, the injection cutting type ground injection method according to claim 2 of the present invention is:
In the injection cutting type ground injection method according to claim 1,
The high-pressure fluid is high-pressure water or a mixture of high-pressure water and air.

Moreover, the injection cutting type ground injection method according to claim 3 of the present invention is:
In the injection cutting type ground injection method according to claim 1,
The injection tube is a single tube rod type, a double tube rod type, a single strainer type, or a double tube double packer type.

Moreover, the injection cutting type ground injection method according to claim 4 of the present invention is:
In the injection cutting type ground injection method according to claim 1,
In the injection pipe, a high-pressure fluid pipe that communicates the high-pressure fluid supply means and the nozzle hole, and an injection material pipe that communicates the injection material supply means and the injection hole are independently incorporated. Features.

Moreover, the injection cutting type ground injection method according to claim 5 of the present invention is:
In the injection cutting type ground injection method according to claim 4,
As the geological improvement injection material, using a main agent and a curing agent that rapidly cures the main agent,
The injection material supply means has a main agent supply means for supplying the main agent and a curing agent supply means for supplying the curing agent,
The injection hole has a main agent hole through which the main agent flows out and a curing agent hole through which the curing agent flows out,
In the injection material pipe, a main agent pipe that communicates the main agent supply means and the main agent hole, and a hardener pipe that communicates the hardener supply means and the hardener hole are independently incorporated. It is characterized by.

  In the injection cutting type ground injection method according to the present invention, after the ground is drilled downward to form a ground hole and reach a predetermined underground depth position, the lower end of the injection pipe is at the underground depth position. Until it reaches the ground hole, inject the high-pressure fluid from the nozzle hole of the injection pipe toward the side of the ground, and rotate the injection pipe to cut the ground around the underground depth position to obtain a substantially disk-like shape. The step of forming the injection gap is repeated while lowering the injection pipe stepwise, and then the injection pipe is raised stepwise, and the injection pipe is set at every depth position in each location where the injection gap is formed. The process of forming the geological improvement region by allowing the geological improvement injection material to flow out from the injection hole and allowing the geological improvement injection material to infiltrate into the ground around the mid-depth position through the injection gap and then solidify. Because of the configuration Can be geological improve without exception substantially in contact or overlap the ground area to the adjacent geological improve region directly under the position it has the effect that. In addition, since a substantially disc-shaped injection gap is formed in the ground, the area of the surface through which the geological improvement injection material permeates is increased, and the injection speed is increased. Therefore, the construction period of the entire injection can be shortened. Furthermore, the geological improvement area obtained by injection is affected by uncertainty due to various factors such as the permeability coefficient of the target ground and its non-uniformity, the viscosity of the geological improvement injection material and the actual gel time. This also has the effect of enabling ground injection that is more uniform and more reliable than before.

  In the embodiment described below, after the ground is drilled downward to form a ground hole and reach a predetermined underground depth position, the bottom of the injection pipe is in the ground hole until it reaches the underground depth position. It is inserted into the nozzle, and a mixture of high-pressure water and air is sprayed from the nozzle hole of the injection tube toward the side of the ground, and the injection tube is rotated to cut the ground around the underground depth position to obtain a substantially disk shape. The step of forming the injection gap is repeatedly performed while lowering the injection pipe stepwise, and then the injection pipe is raised stepwise, and injection is performed at every depth position in each location where the injection gap is formed. Repeat the process of forming the geological improvement region by letting the geological improvement injection material flow out from the injection hole of the pipe, infiltrate the geological improvement injection material in the ground around the middle depth position through the injection gap, and then solidify it. The conventional ground It is easily carried out by applying a simple change to the infusion material produced plant and injection tube of the incoming method. In addition, the construction itself for injecting the geological improvement injection material into the ground is the same as the conventional one, and is the best mode for realizing the present invention.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining the construction procedure of the spray cutting type ground injection method according to the first embodiment of the present invention.

  First, the construction procedure of the spray cutting type ground injection method which is the first embodiment of the present invention will be described.

  First, the ground 1 is drilled downward to form a ground hole 2 that is a substantially cylindrical cavity, and reaches a predetermined first underground depth position (see FIG. 1A).

  Thereafter, the injection tube 20 is inserted into the ground hole 2, and the lower end of the injection tube 20 is made to reach the vicinity of the first underground depth position of the hole bottom 2 a 1 which is the bottom of the ground hole 2. Thereafter, high-pressure air / water H is jetted from the nozzle hole 20N provided in the lower portion of the injection pipe 20 toward the ground 1 on the side of the bottom 2a1 of the ground hole 2. The high-pressure air / water H is a mixture of high-pressure water and air. Further, at the time of the injection of the high-pressure steam H, the injection pipe 20 is rotated at the same time. In this way, the ground 1 around the first underground depth position of the ground hole 2 is cut (see FIG. 1B).

  By injection cutting of the ground described above, a substantially disc-shaped injection gap V1 is formed. Next, the ground 1 is further drilled downward from the hole bottom 2a1 of the ground hole 2, and the ground hole 2 is dug down to reach the second underground depth position. Thereafter, the injection tube 20 is lowered, and the lower end of the injection tube 20 is made to reach the vicinity of the second underground depth position, which is the position of the hole bottom that is the new bottom of the ground hole 2. Next, from the nozzle hole 20N provided in the lower part of the injection pipe 20, the high pressure steam H is injected toward the ground 1 on the side of the bottom of the ground hole 2, and the injection pipe 20 is rotated. In this way, the ground 1 around the second underground depth position of the ground hole 2 is cut to form a substantially disc-shaped injection gap V2. Hereinafter, in the same manner, the ground 1 around the middle depth position up to the fourth underground depth position, which is the underground depth position of the hole bottom 2a2, is cut with high-pressure air and water in a substantially disc-shaped injection gap. V3 and V4 are formed for each middle depth position (see FIG. 1C). Here, the fourth underground depth position corresponds to the nth underground depth position in the claims. The third underground depth position corresponds to the (n-1) underground depth position in the claims.

  Next, in the state where the injection hole of the injection pipe 20 (for example, the injection hole 20a1 at the lower part of the injection pipe 20) is in the vicinity of the lowermost fourth underground depth position, the injection material G for geological improvement is injected from the injection hole 20a1. Spill. The geological improvement injection material G enters the substantially disc-shaped injection gap V4 formed as described above, and reaches the deeper ground through the injection gap V4. At the same time, it penetrates from the ground exposed skin surface of the filling gap V4 into the internal ground (see FIG. 1D). In this case, for example, “double pipe double packer type” injection as described later can be used as the injection method of the geological improvement injection material G by the injection pipe 20. In the case of “double tube double packer type” injection, the injection tube is composed of an outer tube, an inner tube, and upper and lower packers, and the inner tube is used for injection together with the upper and lower packers without moving the outer tube as it is. When the position of the injection hole of the inner tube becomes the position of the injection gap, the geological improvement injection material is injected into the injection gap.

  Thereafter, the geological improvement injection material G is solidified, and the geology of the ground in the thick disk-like (or short columnar) region including the injection gap V4 is improved, thereby forming the first geological improvement region Z1. Is done. Next, the injection hole of the injection tube 20 is set to be near the third underground depth position one step above from the fourth underground depth position. Then, at the third underground depth position, the geological improvement injection material G is caused to flow out from the injection hole near the third underground depth position. The geological improvement injecting material G enters the substantially disc-shaped injecting gap V3 and reaches the deeper ground through the injecting gap V3. At the same time, the ground is exposed from the ground exposed skin surface of the injecting gap V3. It penetrates into the inside. Thereafter, the geological improvement injection material G is solidified, and the geology of the ground in the thick disk-like (or short columnar) region including the injection gap V3 is improved, thereby forming the second geological improvement region Z2. (See FIG. 1E). In this case, as shown in the drawing, the second geological improvement region Z2 is formed so as to substantially contact or overlap the first geological improvement region Z1.

  In the same manner, the geological improvement injection material G is injected into the ground at each intermediate depth position up to the first underground depth position, and the third geological improvement is performed in the ground around the underground depth position. A region Z3 and a fourth geological improvement region Z4 are formed. In this case, the third geological improvement region Z3 is substantially in contact with or overlaps with the second geological improvement region Z2, which is an adjacent geological improvement region immediately below it. Further, the uppermost fourth geological improvement region Z4 is substantially in contact with or overlaps with the third geological improvement region Z3, which is an adjacent geological improvement region immediately below (see FIG. 1F).

  In this way, according to the injection cutting type ground injection method according to the first embodiment of the present invention, the ground injection at the middle depth position in each place is substantially in contact with or overlaps the adjacent geological improvement region immediately below it. It is possible to improve the geology without missing all areas.

  Next, specific configurations of an injection device, an injection tube, and the like for realizing the above-described construction procedure will be described with reference to the drawings. FIG. 2 is a diagram showing the entire configuration of a ground injection device used in the spray cutting type ground injection method according to the first embodiment of the present invention.

  As shown in FIG. 2, the ground injection device 10 includes a main body 11, a high-pressure air / water plant 12, an injection material plant 13, and an injection pipe 20.

  The main body 11 includes a base 11a, a column 11b, an elevating drive unit 11c, and a rotation drive unit 11d. The base 11a is a plate-like member made of steel or the like, and is installed on the ground surface of the ground 1 at the position of the ground hole 2 where the ground injection is performed, and the entire body 11 is placed thereon. It is a member to support. The column 11b is a columnar member that is erected substantially vertically upward on the base 11a. The raising / lowering drive part 11c is supported by the support | pillar 11b, and can be moved up and down vertically using the support 11b. The lift drive unit 11c corresponds to the lift drive means in the claims. The rotation driving unit 11d is supported by the lifting / lowering driving unit 11c so that the injection tube 20 can be securely grasped and the injection tube 20 can be rotationally driven with the longitudinal center line of the injection tube 20 as the rotation center. . This rotational drive part 11d is equivalent to the rotational drive means in a claim.

  The injection pipe 20 is inserted into the ground hole 2 which is a substantially cylindrical hole excavated from the ground surface vertically downward of the ground 1. The outer diameter of the injection tube 20 is set to a value smaller than the inner diameter of the ground hole 2.

  The injection tube 20 is held by the rotation drive unit 11d. Although not shown, the rotation drive unit 11d is provided with a chuck mechanism and a rotation drive mechanism. The chuck mechanism is a mechanism for grasping or releasing the injection tube 20. The rotation drive mechanism is a mechanism for rotating the injection tube 20 held by the chuck mechanism around its central axis.

  For example, a hydraulic drive device having a hydraulic cylinder and a piston can be used as the chuck mechanism of the rotation drive unit 11d and the drive source (not shown) of the elevation drive unit 11c. The hydraulic drive device controls the solenoid valve and the like to feed or discharge the working oil into the hydraulic cylinder, thereby controlling the hydraulic pressure in the hydraulic cylinder and expanding and contracting the piston. In addition, as a drive source of the rotation drive mechanism of the rotation drive unit 11d, other known rotation drive sources such as an electric motor and an internal combustion engine can be used.

  The high-pressure steam / water plant 12 includes a water tank 12a, a high-pressure steam / water delivery pump 12b, a high-pressure steam / water pipe 12c, a high-pressure steam / water control valve 12d, and pressure sensors 12e1 and 12e2. The high-pressure steam-water delivery pump 12b is a mixture of high-pressure water and high-pressure air from water and air that is rotationally driven or linearly reciprocated by a drive source (not shown) and is stored in the water tank 12a. This is a pump that generates high-pressure steam, and the generated high-pressure steam is sent out by a high-pressure steam pipe 12c. Here, the high-pressure steam is equivalent to the high-pressure fluid in the claims. The water tank 12a and the high-pressure steam / water delivery pump 12b constitute high-pressure fluid supply means in the claims.

  The high pressure steam / water pipe 12c is a pipe made of a hard material that can withstand the pressure of the high pressure steam / water, and supplies the high pressure steam / water from the high pressure steam / water delivery pump 12b to the injection pipe 20. The high-pressure steam-water control valve 12d has an actuator (not shown) driven by electricity, and is a valve that can be controlled to open and close by a computer or the like. The pressure sensors 12e1 and 12e2 are pressure detectors for detecting and monitoring the pressure of the high pressure steam in the high pressure steam pipe 12c.

  The injection material plant 13 includes an injection material generation mixer 13a, an injection material delivery pump 13b, an injection material hose 13c, an injection material control valve 13d, and pressure sensors 13e1 and 13e2. The injection material generating mixer 13a puts the raw material or material of the geological improvement injection material into a stirring tank (not shown), and rotates the stirring blades (not shown) provided therein by a rotation drive source. Then, the charged raw materials and the like are mixed and kneaded by stirring to produce a liquid geological improvement injection material. As a rotational drive source (not shown) of the stirring blade, a known drive source such as an electric motor or an internal combustion engine can be used.

  The injection material delivery pump 13b is a pump that is driven to rotate or linearly reciprocate by a drive source (not shown) and delivers the liquid geological improvement material produced by the injection material production mixer 13a. The injection material for improving geology is sent out by the injection material hose 13c. Here, the injection material generating mixer 13a and the injection material delivery pump 13b constitute the injection material supply means in the claims.

  The injection material hose 13c is a tube made of a material that can withstand the injection pressure, and supplies the injection material 20 with the geological improvement injection material from the injection material delivery pump 13b. The injection material control valve 13d has an actuator (not shown) driven by electricity, and can be controlled to be opened and closed by a computer or the like. The pressure sensors 13e1 and 13e2 are pressure detectors for detecting and monitoring the pressure of the injection material in the injection material pipe 13c.

  Moreover, although not shown in figure, said ground injection apparatus 10 has an injection | pouring control apparatus which controls the main body 11, the high pressure steam-water plant 12, and the injection material plant 13 to start or stop. Although not shown, this injection control device incorporates a computer in addition to a switch. By operating this computer from the outside, the horizontal position and the vertical position of the injection tube 20 are set to desired positions. It can be set, and the flow and pressure of high-pressure steam and injection material can be controlled.

  Next, the configuration of the injection tube 20 will be described in more detail. FIG. 3 is a diagram showing a configuration of an injection tube in the ground injection device shown in FIG. FIG. 4 is a diagram showing a more detailed configuration of the inner tube in the injection tube shown in FIG.

  As shown in FIG. 3, the injection pipe 20 has a structure in which a so-called “double pipe double packer type” injection pipe and a high-pressure steam-water jet pipe are combined.

  The injection tube 20 includes an outer tube 21, an inner tube 22, an upper packer 23U, and a lower packer 23L. The outer tube 21 is a hollow tubular member made of steel or the like with both ends open, and the outer diameter is set to a value smaller than the inner diameter of the ground hole 2. In addition, the outer tube 21 is provided with a plurality of outer tube holes 21a which are through-holes communicating the internal cavity with the outside.

  The inner tube 22 is a member accommodated in the outer tube 21 and has a double structure as shown in FIGS. 3 and 4A. That is, a high-pressure air / water cavity 22 b that is a substantially cylindrical cavity extending in the longitudinal direction (substantially vertically up and down) of the inner tube 22 is provided near the center of the inner tube 22. The high-pressure air-water cavity 22b and the above-described high-pressure air-water pipe 12c constitute a high-pressure fluid pipe in the claims.

  The bottom of the inner tube 22 is closed, and as shown in FIG. 4 (B), the lower portion of the high-pressure steam / water cavity 22b is bent at a substantially right angle in a substantially horizontal direction, and a check valve is connected from the central connection port 22e. Through 22c, the inner diameter of the cavity is reduced and communicated with the outside through a small-diameter nozzle hole 22N. The nozzle hole 22N corresponds to the nozzle hole 20N in FIG. Moreover, the top part of the inner tube 22 is an opening, and the top opening of the high-pressure steam / water cavity 22b is connected to and communicates with the tip opening of the high-pressure steam / water pipe 12c described above.

  FIGS. 4C and 4D are diagrams showing a more detailed configuration and operation of the check valve 22c in FIG. 4B. As shown in FIG. 4C, the valve body 22g attached to the inner tube 22 with a hinge 22f in the valve chamber (valve space) of the check valve is in a state in which the high-pressure air / water H does not enter from the right side of the figure. Then, it is pressed against the locking portion 22i by a spring (for example, a compression coil spring) 22h, and the check valve is closed. Next, when the high-pressure steam H enters from the right side of the figure, the valve body 22g is pushed to the left in the figure by the pressure of the high-pressure steam H, and the spring (for example, compression coil spring) 22h contracts by this pressure. The valve element 22g is rotated toward the left in the figure by the hinge 22f. As a result, the check valve is opened, and the high-pressure steam H can flow from the central communication port 22e through the valve chamber of the check valve 22c to the nozzle hole 22N through the nozzle communication port 22k. Further, when the pressure of the high-pressure steam H is lowered, the check valve 22c is closed, so that the high-pressure steam H is prevented from flowing back to the high-pressure steam cavity 22b and the like. Said spring 22h should just be the structure which can pass the high pressure steam / water H, and can use well-known springs other than a compression coil spring (string wound spring).

  On the other hand, inside the inner tube 22, a substantially cylindrical cavity extending in the longitudinal direction (substantially vertical up and down direction) of the inner tube 22 around the high-pressure air-water cavity 22 b at the center of the inner tube 22. An injection material cavity 22d is provided. The injection material cavity 22d and the above-described injection material hose 13c constitute an injection material pipe in the claims.

  The bottom of the inner tube 22 is closed, and the lower part of the injection material cavity 22d is closed. Further, the outer wall of the inner tube 22 is provided with a plurality of injection material cavities 22 d and a plurality of inner tube injection holes 22 a which are through holes communicating with the outside of the inner tube 22. The top of the inner tube 22 is an opening, and the top opening of the injection material cavity 22d is connected to and communicates with the tip opening of the injection material hose 13c described above.

  As described above, in the inner pipe 22, the high-pressure steam / water cavity 22 b for high-pressure steam / water and the injection-material cavity 22 d for the injection material are independent of each other, that is, inside the inner pipe 22, fluid flows between each other. Built-in so that it cannot be moved.

  Further, around the lower portion of the inner tube 22, a lower packer 23L and an upper packer 23U are installed above the lower packer 23L. These packers are fitted or fixed to the inner tube 22 by, for example, a protrusion 22m or a fixture 24. The lower packer 23L and the upper packer 23U are made of a rubber-based material having elasticity, and are formed in a shape in which a circular opening is formed in the center of the disk. The outer diameters of the lower packer 23L and the upper packer 23U are set to be slightly larger than the inner diameter of the outer tube 21. Therefore, when the inner tube 22 is pushed into the outer tube 21 with the lower packer 23L and the upper packer 23U attached, the lower packer 23L and the upper packer 23U are in close contact with the inner wall of the outer tube 21 due to the elasticity of the rubber-based material. In addition, liquid or the like can be prevented from leaking from the upper side to the lower side of the lower packer 23L. In exactly the same manner, it is possible to prevent liquid or the like from leaking upward from below the upper packer 23U. Further, the inner tube injection hole 22a described above is provided only in a range sandwiched between the upper packer 23U and the lower packer 23L.

  With the above configuration, when the inner tube 22 is raised and lowered, the upper packer 23U and the lower packer 23L are also raised and lowered together, and are spaces surrounded by the upper packer 23U, the lower packer 23L, the inner tube 22 and the outer tube 21. The small chamber 20S also moves. The injection material for geological improvement enters the injection material cavity 22d of the inner tube 22 from the injection material hose 13c, enters the small chamber 20S from the inner tube injection hole 22a opened only in the small chamber 20S, and is in a range where the small chamber 20S is located. It flows out from the outer tube hole 21 a of the outer tube 21 to the external ground hole 2. Therefore, a plurality of outer tube holes 21 a are formed substantially uniformly in the outer tube 21, but a position where a small chamber 20 </ b> S that is a space surrounded by the upper packer 23 </ b> U, the lower packer 23 </ b> L, the inner tube 22, and the outer tube 21 exists. In addition, injection can be performed only when the injection control valve 13d is open. The outer tube hole 21a corresponds to the injection holes 20a1 and 20a2 in FIG.

  On the other hand, the injection of the high-pressure steam water is performed only when the nozzle hole 22N of the inner tube 22 is exposed below the lower end 21b of the outer tube 21 and the high-pressure steam-water control valve 12d is open. It can be done. In this state, if the inner tube 22 and the outer tube 21 are rotated together, the ground around the ground hole position in the ground hole 2 is cut to form a substantially disk-shaped injection gap. can do.

  In the above ground injection device 10, when drilling, a drilling rod (not shown) provided with a known excavation bit (not shown) is used, and this drilling rod is attached to the main body 11 described above. It may be mounted and drilled. In this case, the ground injection device 10 equipped with the drilling rod constitutes the drilling means in the claims.

  The diameter of the nozzle hole 20N (or 22N) is about 1 to 10 millimeters. The pressure of the high-pressure air / water is about 20 to 70 MPa (megapascal), and the speed is about 300 meters / second. When such high-pressure steam is used, the diameter of the substantially disc-shaped injection gap V1 formed in the ground by ground spray cutting can be set to about 2 to 3 meters, for example. The injection material for geological improvement penetrates into the ground from the upper surface and the lower surface of the substantially disk-shaped injection gap V1 formed in the ground. Therefore, if the vertical distance (depth difference) of each position in the ground (depth position in each location) where ground injection cutting and injection are performed is about 1 meter, the geological improvement injection material is about 0. If it penetrates 5 meters or more, the geological improvement areas adjacent to each other in the vertical direction will overlap. Because it is easy to penetrate the geological improvement injection material of about 0.5 meters into the ground, the vertical distance (depth difference) of each position in the ground (depth position in each place) where ground injection cutting and injection are performed is An interval of about 1 meter is sufficient.

  The present invention can also be realized by configurations other than the first embodiment described above.

  For example, in the above-described embodiment, a substantially cylindrical hole excavated from the ground surface vertically below the ground is taken as an example of the ground hole, but a ground hole having another configuration may be used. For example, a hole excavated from the ground surface obliquely below the ground, or on a slope surface or a cliff or the like, obliquely above the ground may be used as the ground hole. Moreover, the cross-sectional shape of the ground hole may be a cross-section other than a substantially circular shape.

  In the first embodiment, an example in which a plurality of nozzle holes 20N (22N) are provided has been described. However, the number of nozzle holes for high-pressure fluid ejection may be one.

  As the high-pressure fluid, only high-pressure water that does not contain high-pressure air may be used.

  Further, the check valve 22c may be installed in the vicinity of the inlet of the high-pressure air / water cavity 22b above the injection pipe 20. As the check valve, in addition to those described above, those having other known configurations can be used. For example, a check valve using a ball-like (substantially spherical) member as a valve body can be used.

  Moreover, as a geological improvement injection material, it is good also as what is called a "two-component mixing type" using the main ingredient and the hardening | curing agent which hardens the said main ingredient rapidly. In this case, as the injection material supply means, a main agent supply means for supplying the main agent and a hardener supply means for supplying the curing agent are provided, and as the injection holes, the main agent hole for allowing the main agent to flow out, and the hardening agent to flow out. In the injection material piping, there are a main agent pipe connecting the main agent supply means and the main agent hole, and a hardener pipe connecting the hardener supply means and the hardener hole, respectively. It may be built in. In this way, it is possible to use an instantaneous-type injection material for improving geology with a very short gel time.

  Moreover, the injection tube in this invention can use all what is used in the conventionally well-known construction method. For example, in addition to the “double tube double packer type” in the first embodiment, a single tube rod type injection tube can be used. In the case of a double-pipe double packer type injection tube, the outer tube of the injection tube is not moved as it is, but the inner tube is sequentially lifted together with the upper and lower packers to the position of the injection gap V2, etc. The geological improvement injection material is injected into the injection gap V2 etc. at the position of the gap V2, etc., but when using a single pipe rod type injection pipe, the injection pipe (single pipe) itself is sequentially pulled up, The lower end of the injection tube having the injection opening is positioned at the injection gap V2 and the like, and the geological improvement injection material is injected into the injection gap V2 and the like. In addition to the above, as the injection tube in the present invention, a double tube rod type, a single strainer type, a double tube single phase type, a double tube double phase type, and the like can also be used.

  INDUSTRIAL APPLICABILITY The present invention can be implemented in a construction industry where a ground injection method is applied as a ground improvement method for a foundation ground of a structure or a building, and can be used in these industries. Moreover, an injection tube and an injection apparatus can be manufactured in the machine industry which manufactures these, and can be utilized in these industries.

It is a figure explaining the construction procedure of the injection cutting type ground injection method which is the 1st example of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole structure of the ground injection | pouring apparatus used for the injection cutting type ground injection | pouring method which is 1st Example of this invention. It is a figure which shows the structure of the injection pipe in the ground injection apparatus shown in FIG. It is a figure which shows the further detailed structure of the inner tube | pipe in the injection tube shown in FIG. It is a figure explaining the construction procedure and problem of the conventional ground injection construction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground 2 Ground hole 2a1-2a2 Hole bottom 10 Ground injection apparatus 11 Main body 11a Base 11b Post 11c Elevation drive part (elevation drive means)
11d Rotation drive part (rotation drive means)
12 High pressure steam water plant 12a Water tank (High pressure fluid supply means)
12b High-pressure steam-water delivery pump (high-pressure fluid supply means)
12c High-pressure air-water pipe (high-pressure fluid piping)
12d High-pressure air-water control valve 12e1, 12e2 Pressure sensor 13 Injection material plant 13a Injection material generation mixer (injection material supply means)
13b Injection material delivery pump (injection material supply means)
13c Injection material hose (injection material piping)
13d Injection material control valve 13e1, 13e2 Pressure sensor 20 Injection pipe 20a1, 20a2 Injection hole 20N Nozzle hole 20S Small chamber 21 Outer pipe 21a Outer pipe hole (injection hole)
21b Lower end 22 Inner tube 22a Inner tube injection hole 22b High-pressure air-water cavity (high-pressure fluid piping)
22c Check valve 22d Injection material cavity (injection material piping)
22e Central connection port 22f Hinge 22g Valve element 22h Spring 22i Locking part 22k Nozzle connection port 22m Protrusion 22N Nozzle hole 23L Lower packer 23U Upper packer 24 Fixing tool 201 Ground 202 Ground hole 202a Bottom 220 Injection pipe 220a1, 220a2 Injection hole G Implant for improvement H High pressure steam N11-N14 Unmodified area V1-V4 Void for injection Z1-Z15 Geological improvement area

Claims (5)

After drilling the ground downward by the drilling means and the lift drive means to form a ground hole and reach a predetermined first underground depth position,
An injection pipe having an injection hole in the lower part and having a nozzle hole formed in the lower side is inserted into the ground hole until the lower end reaches the first underground depth position, and high-pressure fluid supply means is provided in the injection pipe. The high pressure fluid is ejected from the nozzle hole toward the side ground, and the injection pipe is rotated by a rotation driving means to cut the ground around the first underground depth position of the ground hole. Forming a disk-shaped injection gap,
Next, after drilling the ground further from the bottom of the ground hole by the drilling means and the lift drive means to dig up the ground hole and reach a predetermined second underground depth position, the lower end of the injection pipe is The ground hole is lowered by the elevating driving means until the second underground depth position is reached, the high pressure fluid supply means ejects the high pressure fluid from the nozzle hole toward the side ground, and the injection pipe is Rotating by a rotation driving means, cutting the ground around the second underground depth position of the ground hole to form a substantially disc-shaped injection gap,
In the same manner, the ground around the various medium depth positions up to the predetermined nth underground depth position is cut with the high-pressure fluid to form a substantially disc-shaped injection void for each medium depth position,
Next, an injection material supply means is connected to the injection tube in a state where the lower end of the injection tube is at the lowest nth underground depth position, and the geological improvement injection material flows out from the injection hole and passes through the injection gap. The first geological improvement region is formed by solidifying after injecting the geological improvement injection material into the ground around the nth underground depth position,
Next, after the lower end of the injection pipe is pulled up to the (n-1) underground depth position one step above, the injection material supply means causes the injection material for geological improvement to flow out from the injection hole, and the first through the injection gap. (N-1) After infiltrating the geological improvement injection material in the ground around the underground depth position and substantially in contact with the first geological improvement region or overlapping the first geological improvement region Solidify to form the second geological improvement zone,
In the same manner, in the ground around each middle depth position up to the first underground depth position, the ground substantially touches the adjacent geological improvement region immediately below or overlaps with the adjacent geological improvement region immediately below. An injection cutting type ground injection method characterized in that a geological improvement region solidified after injecting a geological improvement injection material through the injection gap in the middle region is formed for each middle depth position. In the injection cutting type ground injection method according to claim 1,
The high-pressure fluid is high-pressure water or a mixture of high-pressure water and air. In the injection cutting type ground injection method according to claim 1,
The injection cutting type ground injection method, wherein the injection pipe is a single pipe rod type, a double pipe rod type, a single strainer type, or a double pipe double packer type. In the injection cutting type ground injection method according to claim 1,
In the injection pipe, a high-pressure fluid pipe that communicates the high-pressure fluid supply means and the nozzle hole, and an injection material pipe that communicates the injection material supply means and the injection hole are independently incorporated. A feature of injection cutting type ground injection method. In the injection cutting type ground injection method according to claim 4,
As the geological improvement injection material, using a main agent and a curing agent that rapidly cures the main agent,
The injection material supply means has a main agent supply means for supplying the main agent and a curing agent supply means for supplying the curing agent,
The injection hole has a main agent hole through which the main agent flows out and a curing agent hole through which the curing agent flows out,
In the injection material pipe, a main agent pipe that communicates the main agent supply means and the main agent hole, and a hardener pipe that communicates the hardener supply means and the hardener hole are independently incorporated. A spray-cutting ground injection method characterized by

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