JPH0154488B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial field of application: The present invention is capable of injecting chemical solutions for soil improvement such as strengthening the ground or stopping water, all at once over a wide area from multiple locations in the vertical direction of a single injection pipe, almost uniformly. It relates to a chemical injection method that allows injection under certain conditions. Conventional technology: Various technologies have already been developed for chemical injection methods, in which chemical liquid is injected into the ground in a required area to stabilize the soil quality, in order to strengthen weak ground or prevent water leakage or spring water caused by excavation work. has been developed and put into practical use. However, when inserting the injection rod into the ground and injecting the chemical over a wide area in the vertical direction, the injection rod must be rotated to the required depth and drilled into the ground, and then the rod should be inserted into the ground. Methods such as one in which the rod is pulled up in stages and repeated injection at each stage, and one in which the chemical solution is injected all at once through discharge holes that are pre-drilled at appropriate pitches from the tip to the middle of the rod are being adopted. For example, as the latter method,
It is known from Japanese Patent Publication No. 30327, Japanese Patent Publication No. 48-23380, etc. Problems to be solved: Traditionally, the former method requires a lot of work, and when trying to rapidly inject a large amount of chemical into the ground, the injection pressure has to be high, which can damage the soft parts of the stratum. The chemical solution may transfer to weak cracks, etc.
There were disadvantages such as the so-called escape phenomenon, which resulted in a large loss of chemical solution, and the fact that it was not injected into the necessary areas, resulting in localized condensation. Therefore,
Since gradual injection is unavoidable, workability is naturally reduced significantly and construction costs increase. In addition, when using the latter method, the chemical liquid injected through the rod does not spray out a fixed amount from each discharge hole, and a large amount of liquid may be injected into areas where the discharge area is soft ground or where there is so-called low resistance. In extreme cases, it is only useful in some holes, and uniform chemical injection is completely undesirable and results in unsatisfactory geological improvement. It is difficult to expect an improvement in efficiency due to the necessity of slow injection in order to achieve this goal. Means for Solving the Problems: The object of the present invention is to solve the problems in the conventional techniques and provide a method that can effectively carry out multi-stage simultaneous injection of chemical solutions using an injection tube rod. That is, the present invention provides a method in which pipe lines communicating with the inner pipe are fitted at appropriate intervals in the middle part of a double-tube type chemical liquid injection rod, and the pipes are connected to the outer pipe by screwing or welding. In addition, a rod connecting body is provided with a large number of upper and lower communication holes that communicate with the annular passage between the inner and outer pipes, and a valve at the tip of the rod opens and closes depending on the injection pressure difference between the inner and outer pipes. Each rod connection body is equipped with a shutoff valve that closes the liquid outlet leading from the outer tube side to the cutting blade when the pressure increases, and each rod connection body has a shutoff valve that connects the inner tube side to the outer tube side, crossing the axis. A multi-stage simultaneous injection device is used, which is equipped with a liquid ejection piece that has a liquid ejection hole fitted with a stopper that ejects and separates when the pressure inside the pipe exceeds a certain pressure. First, with the liquid ejection holes at each stage closed and the stop valve at the rod tip open, low-pressure drilling anti-friction fluid is supplied to the cutting blade through the outer pipe side and inserted into the hole to the injection depth. Next, after increasing the liquid pressure on the inner pipe side and closing the shutoff valve, the main condensing agent is supplied to one pipe and the curing aid is supplied to the other pipe in approximately equal amounts at extremely high pressure, and they are arranged in multiple stages. By discharging the stopper of each liquid injection hole into the ground and maintaining the temporary side pressure at the injection nozzle part at a high pressure, the injection chemical liquid of each stage is injected into the ground in an approximately equal amount, and it is evenly distributed over a wide range. This is a chemical injection method that allows multiple chemical injections to be performed all at once. The injection chemical solution used in the present invention may be a conventionally used two-component type chemical solution, which includes a base agent and a curing agent for curing the base agent. Typical examples of these include the combinations shown in the table below.

[Table] It is preferable that both the inner main agent and the curing agent be of true solution type. In the method of the present invention, most of the mechanical devices used for injection may be those conventionally used, but it is desirable that the liquid supply pump be one whose discharge amount does not fluctuate as much as the pressure fluctuates. In addition, the nozzle part that is inserted into the ground and discharges the chemical liquid requires a combination of a special valve body and discharge nozzle, and this nozzle part is arranged in multiple stages to uniformly cover a wide range in the rod axis direction. Consolidation treatment is performed. Function: In the present invention, during operation, an injection pipe rod is used, which is constructed by arranging a required number of rod connectors each having a chemical liquid ejection hole fitted with a stopper in the middle part as described above, and is connected to the destination ground by known means. Insert a hole into the hole. During drilling, an anti-friction liquid (mainly water) is supplied to the cutting blade from the liquid outlet at the tip of the rod, which is open through the outer tube. After the injection pipe rod has been inserted into the ground to the required depth, the supply of anti-friction liquid is stopped and when switching to chemical injection operation, one of the chemical liquids, such as hardening aid liquid, is first supplied to the inner pipe side. , close the stop valve at the tip. Thereafter, a chemical solution, for example, a main agent solution for coagulation, is also supplied to the outer tube side. When both chemical solutions are supplied, they are pumped at a pressure higher than the normal supply pressure, and the liquid outlets other than the extremely small diameter injection nozzles installed in each rod connection are closed, so the pipes between each liquid injection hole are closed. Decompression due to pressure loss of the liquid due to flow in the road becomes almost negligible at any position, and by passing through the injection nozzle, the pressure head is converted to a velocity head and flows out, so it does not flow into the ground. After the stopper of the nozzle hole, which had been closed for protection during insertion into the borehole, releases the chemical into the ground, the chemical solution can be injected into the ground over a wide area in approximately the same condition at each stage. Embodiment: Hereinafter, the special nozzle part and chemical injection method of the present invention will be explained in detail with reference to the drawings. 2 is an outer tube, and 3 is an inner tube, each of which has approximately the same length as the required length in the lower half of the injection tube rod. The inner and outer tubes 2 and 3 are connected through a rod connecting body 10, and the rod connecting body 1
0 are arranged at required intervals. 30 is a cutter bit attachment piece attached to the tip of the injection tube rod, and 5 is a well-known rotary joint to which drug solution supply tubes from a pump (not shown) are connected to the inner and outer tubes, respectively. As shown in FIGS. 2 to 4, the rod connector 10 has a diameter approximately equal to the outer diameter of the outer tube 2 as the injection tube rod 1 and an appropriate length, and an inner tube 3 in the axial direction at the center. A central hole 11 with a diameter approximately equal to the inner diameter of
At both the upper and lower ends of the central hole 11, there are provided inner tube insertion portions 12 having an appropriate length and a diameter into which the end of the inner tube 3 can be inserted, and on the outer periphery of both the upper and lower ends. A screw 13 is provided with a required length so that the ends of the tube 2 can be screwed together, and the position corresponds to the annular space formed by the outer tube 2 and the inner tube 3 when they are connected. A plurality of upper and lower communication holes 14 are formed concentrically and parallel to the axis at appropriate intervals. However, this vertical communication hole 14 is not provided in one place on a straight line passing through the center in the cross section, and the communication hole 14' provided in the opposite position is provided from the upper side to the middle part without penetrating vertically. The liquid ejecting piece 20 is drilled only up to the mounting hole 15. Furthermore, a stepped mounting hole 15 and a stepped bolt hole 16 for inserting and mounting a liquid jet piece are bored in a suitable position in the middle of the rod connecting body 10 in a straight line across the axis, as shown in the third figure. A liquid spouting piece 2 is fitted into the mounting hole 15.
0 consists of a head part 20' having a large diameter so that its outer diameter fits into the mounting hole 15, and a small diameter part 20'' which projects into the central hole 11 by an appropriate length. O-ring packings 23, 23' are interposed between the outer periphery of ' and between the step end face and the mounting hole step to seal the inside and outside. A stepped liquid ejection hole 21 is bored, and a screw hole 22 is connected to the rear end, and a hole of an extremely small diameter (a hole 22) is formed at a position corresponding to the communication hole 14' on the outer tube side during bonding. It has an area that is approximately 1/1600 of the area of the inner tube flow path shown in FIGS. 3 and 4, a diameter of approximately 0.3 to 0.4 mm, and an area that is approximately 1/300 of the total area of the outer tube flow path. ) is bored in the liquid jet hole 21 , and a liquid jet nozzle 24 having an extremely small diameter hole facing the liquid jet hole 21 is located above the part protruding into the central hole 11 . 24' part is bored, and this both liquid injection nozzle 2
4 and 24' are a nozzle piece with a sloped surface formed of an ultra-hard material such as ceramic, and a liquid ejecting piece 2.
0', it is fitted into a previously drilled hole with a reverse slope and is made integral with adhesive. This liquid ejecting piece 20 is fixed integrally by screwing a bolt 17 into a screw hole 22 from a bolt hole 16 located opposite to the mounting hole 15 thereof. In addition, at this time, the liquid injection nozzles 24, 2
4' are preferably fixed toward the chemical solution supply side (upper side in the figure). Seal rings 25 are fitted on the inner circumferential surface of the liquid jet hole 21 at both sides of the liquid jet nozzle 24 communicating with the outer tube to prevent leakage of the liquid. As shown in FIG. 5, the crown cutter attachment piece 30 at the tip of the injection tube rod 10 has an appropriate length that matches the outer diameter of the injection tube, and is divided into an upper half 31 and a lower half 32. The upper half 31 is provided with a connection fitting hole 33 for the inner tube 3 at the center, and a male threaded portion 34 for screwing the outer injection tube is formed on the upper outer periphery. Pipe connection fitting hole 33
A cylinder 36 configuring a part of the shutoff valve 35 is provided at the bottom with a downward opening.
A piston part 37 having a valve element 35' at the tip end of the axis is fitted into the part, and a large number of chemical liquid passage holes 39 on the outer tube side are formed concentrically in the connecting part 31 between the central part and the outer peripheral forming part. A through-hole is formed, and the lower half 32 is connected to the upper half 3.
1', a partition wall 38 is provided which is bored around a through hole 35'' into which the valve element 35' at the tip of the piston 37 in the cylinder 36 fits, forming a part of the shutoff valve 35. A cylindrical piece 40 equipped with a crown cutter bit of a well-known structure is screwed to the lower part.The valve element 35' on the piston 37 side constituting the shutoff valve 35 has an O-ring packing 4 on the outer periphery.
1 is fitted into the through hole 35'' of the partition wall 38, the O-ring packing 41 seals the space between the inside of the cylinder 36 and the inner tube insertion part 33. A communication hole 33' is provided in the hole 33'.Next, a method of applying the construction method of the present invention to actual ground injection will be explained.When the device configured as described above is inserted into the target ground for improvement, it is Rotate the injection tube rod 1 (rotate in the screwing direction at each connection to prevent the threaded portion from loosening and coming off), and press an anti-friction liquid (for example, water) for drilling into the inside of the outer tube 2. The material is then sent to the crown cutter 4 at the tip of the rod, excavated, and penetrated to the required depth.The pressure at this time is as low as that of conventional drilling means (for example, 5 kg/cm ² or less, preferably 2 kg/cm ² or less). A stopper 26 is fitted into the liquid spout hole 21 at the rod connection body 10 portion for liquid passing through the flow path in the outer tube 2, and the seal ring 2
3, 25 and the stopper 26, the liquid injection hole 21
is closed, so the hydraulic pressure acting on this part will not leak to the outside (this is configured in advance), and the shutoff valve 35 in the cutter attachment piece 30 is closed on the outer pipe side. Since the top surface side of the piston 37 is at or near atmospheric pressure relative to the pressure of the liquid flowing through the through hole 39, the pressure difference between the anti-friction liquid pressure acting on the end surface on the protruding side of the valve 35' causes the cylinder to The piston 37 is pushed back into the through hole 35''.
The valve 35' is separated from the valve 35', that is, the valve is opened, and the liquid is supplied to the cutting portion without any hindrance, thereby facilitating the entry of the injection pipe rod into the excavation. After the injection pipe rod 1 has entered the target depth for ground improvement, the supply of the excavation friction fluid is stopped, and instead of this, two types of well-known coagulation chemicals are added, and the inside of the inner pipe 3 is filled with, for example, a hardening aid solution ( (hereinafter referred to as liquid B), and the main agent liquid for coagulation (hereinafter referred to as liquid A) inside the outer tube 2.
, respectively. When both liquids A and B are supplied to the inner tube 3 side, liquid pressure acts directly on the piston 37 of the stop valve 35 provided in the cutter attachment piece 30 at the tip of the rod 1.
The valve 35' at the tip of the piston 37 is pushed into the through hole 35'' to close the flow to the crown cutter attachment side, and both chemical solutions are supplied to both the inner and outer pipes.
Once the rod is filled, it is ejected from the nozzle toward the ground. When supplying liquid to the rod, if both liquids A and B are kept almost equal and the supply pressure is extremely high (for example, 100 kg/cm ² ), the spaces in both the inner and outer pipes 2 and 3 can be filled. The inflowing liquid pressure acts from the liquid injection nozzle 24' of the liquid injection piece 20 provided on each rod connection body 10 to the stopper plug 26 fitted inside the liquid injection piece 20, and a high-pressure B The liquid instantly blows the stopper 26 into the ground,
The liquid ejection hole 21 opens. Then, the B liquid is ejected from the liquid injection nozzle 24', and the A liquid is ejected from the liquid injection nozzle 24 through the communication hole 14' connected to the outer pipe side, respectively, into the liquid injection hole 21, where they are mixed and at the same time It is injected toward the side at high speed, and as the injection tube rod rotates, the mixed chemical solution is forced into the surrounding ground. This chemical solution is press-fitted into the ground at the same time from each of the plurality of ejection holes 21 provided in the lower half of the injection pipe rod 1 to the corresponding portions. The liquid injection nozzle 2 first flows out into the liquid injection hole 21.
The holes 4 and 24' have extremely small diameters, and the supply pressure of each chemical solution is extremely high, so the flow within the pipe between the respective liquid injection nozzles arranged at appropriate intervals is reduced. The depressurization caused by the pressure loss of the liquid due to this is almost negligible at any position, and as a result, the liquid is ejected under almost the same conditions, and moreover, it is possible to use an extremely small diameter liquid injection nozzle. By passing it through, the pressure head is converted to a velocity head, lowering the injection pressure into the ground,
Since the speed head allows the chemical solution to be injected deep into the body, localized condensation of the chemical solution can be prevented. In this way, by increasing the supply pressure and injecting at a low discharge at the injection part, swelling of the ground does not occur, and the injection range is almost set to prevent excessive chemical injection, and moreover, it is possible to simultaneously inject at multiple positions. Therefore, a large injection range in the vertical direction can be obtained with a single injection operation. When increasing the depth and needing to inject over a wide area vertically, first dig the injection pipe rod to the deepest point, perform the chemical injection operation, and then pull the rod upward as appropriate in the second step. Then, the chemical solution is injected again, and if necessary, the rod of the required size is pulled up again and the chemical solution is injected. By repeating this operation, a wide range of chemical injection work can be carried out in the vertical direction by digging a single injection pipe rod within the range that can be injected from that rod.
It has become possible to significantly improve efficiency compared to conventional construction methods. In addition, in such an operation, after the stopper is pushed out into the ground by the initial injection of chemical liquid, the rod is pulled up and the inside of the liquid spout hole 21 in each liquid spout piece 20 is filled until the rod is pulled up and the next chemical injection is performed at the required location. teeth,
After the supply of both chemicals is stopped, the two chemicals flowing in are mixed in the liquid jet hole 21 and remain condensed, keeping the liquid jet hole 21 in a closed state, so the injection tube rod is pulled up and moved. It acts to prevent earth and sand from entering this hole. After moving upward, when the chemical solution is force-fed and the injection operation begins,
Liquid injection nozzles 24, 24' are connected to the liquid injection hole 21.
Due to the high-speed jet ejected from the container, this coagulated agent is blown open like a stopper, and does not interfere with the injection operation. The pitch of the liquid ejection holes provided in the injection tube rod can be set arbitrarily, but in some cases, the intervals may be set relatively large, and during the second injection of chemical liquid, the pitch of the liquid ejection holes may be set as desired. If the rod is pulled up by, for example, 1/2 of the set pitch, it is effective because a small number of liquid ejection holes can be arranged without difficulty and the chemical liquid can be effectively injected over a wide range. The structure of the liquid ejecting part is not limited to the above embodiment. For example, as shown in FIG. Liquid injection nozzle pieces 27, 2 each having an independent extremely small diameter hole with respect to the flow path
7' is installed so that the liquids ejected from both liquid injection nozzle pieces are mixed and ejected outward at the same time, and a stopper 25' is fitted into the hole forming this mixing part. Can be implemented. In the construction method of the present invention, as described above, it goes without saying that the injection pipe rod can be used by digging and inserting it not only in the vertical direction but also in the lateral direction. Effects of the invention: As described above, according to the method of the present invention, extremely small diameter liquid injection nozzles are arranged in the liquid injection holes provided in multiple stages in the injection pipe rod so as to communicate with each liquid A and B. By supplying each chemical solution at high pressure,
The pressure drop in the pipeline is negligible, the liquid is mixed at each multi-stage liquid ejection hole, the pressure head is converted to a velocity head, and the chemical liquid can be injected over a wide range without difficulty. Moreover, it eliminates problems such as swelling of the ground due to injection,
Rational drug injection became possible. Furthermore, according to the method of the present invention, by raising and moving the injection tube rod vertically within the required range, it becomes possible to inject chemicals over a wide range by arranging a small number of liquid ejection holes. By reducing the number of places where injection pipe rods are driven, the purpose of the work can be accomplished.As a result, work efficiency has been significantly improved, and ground improvement can now be carried out economically. Furthermore, the rod connecting body of the injection pipe rod to be transferred can be connected to the intermediate outer pipe by welding as necessary, and even with such a configuration, if a failure occurs at the liquid ejection part, Since the liquid spout piece can be removed and repaired, work can be carried out without any problems.

[Brief explanation of drawings]

The drawings show one embodiment of the equipment used in the chemical injection method of the present invention, in which Fig. 1 shows the whole, Fig. 2 is a vertical cross-sectional view showing the connection part of the injection pipe rod, and Fig. 3 4 is an enlarged detailed view of the liquid spouting part, FIG. 4 is a view taken along line A-A in FIG. 3, FIG. It is another example figure of a spout part. DESCRIPTION OF SYMBOLS 1... Injection tube rod, 2... Outer tube, 3... Inner tube, 4... Cutting blade for drilling, 10... Rod connection body, 11... Center hole, 12, 33... Inner tube insertion part , 13...Screw, 14...Upper and lower communication hole, 14'
...Communication hole, 15...Mounting hole, 16...Bolt hole, 17...Bolt, 20...Liquid spout piece, 21...
...liquid spout hole, 26...stopping plug, 24, 24'...
Liquid injection nozzle, 27, 27'...Liquid injection nozzle piece,
30... cutter attachment piece, 35... closing piece,
35'...Valve, 35''...Through hole, 36...Cylinder, 37...Piston.

Claims (1)

[Claims] 1. Pipe lines communicating with the inner tube are fitted at appropriate intervals in the middle of the double tube type drug injection rod, and the tubes are connected to the outer tube by screwing or welding. A rod connection body with a large number of upper and lower communication holes communicating with the annular passage is arranged,
The tip of the rod is equipped with a shutoff valve that closes the liquid outlet leading from the outer tube to the cutting blade when the valve opens and closes due to the injection pressure difference between the inner and outer pipes and the pressure on the inner pipe increases. The rod connection body is equipped with a very small diameter injection nozzle that crosses the axis and communicates with the inner tube side and the outer tube side, and has a stopper that blows out and separates when the pressure inside the tube exceeds a certain pressure. Using a multi-stage simultaneous injection device equipped with a liquid spout piece having a fitted liquid spout hole, first close the liquid spout holes at each stage, open the stop valve at the tip of the rod, and then A low-pressure drilling anti-friction liquid is supplied to the cutting blade through the hole to insert the hole to the injection depth, and then the liquid pressure on the inner pipe side is increased to close the shutoff valve. The curing aid is supplied in approximately equal amounts at extremely high pressure to the pipes, and the stopper of each liquid jet hole arranged in multiple stages is discharged into the ground, thereby maintaining the primary pressure at the injection nozzle part at a high pressure. This multi-stage simultaneous injection method is characterized by the fact that the chemical liquid injected at each stage is injected into the ground in approximately the same amount, and the chemical liquid can be uniformly injected over a wide range all at once.