JPS6047115A - Ground improvement work by freely performing excavation and grouting - Google Patents

Abstract

PURPOSE:To freely perform excavation and grout injection while measuring the electric resistance of the ground by a method in which a swivel for multiple tube, a rotary rod for connection, and a rotary rod for connection with electrode are connected with each other, and a drill edge and a grout monitor are provided at the tip thereof. CONSTITUTION:While turning a tube for excavation, electric current is flowed from an external power source to the terminal of the swivel head each time a given depth is reached to measure the electric resistance of untreated ground, and chemical grout is injected. The chemical grout is injected while turning the rod, and when the injection of chemical grout is discontinued on the way of the injection work, the inner and outer nozzles 37 and 38 are soon closed by recovery force of a rubber valve. Since the chemical grout is not hardened thereby, the injection of chemical grout can be made any time without causing any trouble in the vertical slide action of the piston.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of confirming the range of chemical injection (hereinafter referred to as chemical injection) in ground stabilization work, and adding additional chemical at a desired location whenever the chemical injection condition is insufficient. This relates to a ground improvement method that allows for free excavation and chemical injection.

The method of pouring chemicals into the ground is rapidly developing because it is an effective method for increasing the strength of soft ground or stopping water.

Various ground improvement methods have been used for a long time, but currently, the single pipe method uses a single pipe rondo or a single pipe strainer, and the double pipe double bunker injection method, double pipe or six-pipe method. It can be broadly divided into the multiple pipe construction method, which involves pipe rond injection.

These methods are easy to work with and have the lowest cost because drilling and chemical injection are carried out using the same rod. Complexity is added in hopes of achieving an effect.

On the other hand, in pursuit of simplification or reliability of the drilling of the ground to be improved and the subsequent chemical injection work, many studies have been made regarding injection pipes, and various proposals have actually been made.

However, various factors are intertwined, such as the complexity of the ground layer to be constructed, groundwater trends, types of injection chemicals, injection pressure, injection method, and differences in gel time.
It is difficult to accurately judge the injection status, and there is still no perfected technique for dealing with the injection and the situation after confirming it.

In view of this point, the inventors of the present invention conducted extensive studies and conducted excavation of the ground and chemical injection work using a combination of specific chemical injection pipe devices, and measured the chemical injection area during the construction period. We have established a construction method that allows for additional chemical injection in areas where there is insufficient water.

That is, the present invention provides a multi-pipe swivel having electrical signal terminals, a connecting rotary rod in which cable conduits are arranged in the multi-pipe tubes, and a connecting rotary rod with electrodes in which cable conduits are arranged on the outer wall. When the necessary number of these are connected, and at least two fluid flow paths are secured at the tips of the two, and the fluid is passed only through the outer flow path, the plug is supported upward by the pushing up of the spring, and the excavation '
The fluid is ejected from the side fluid outlet in the direction of the pipe axis to excavate the ground, and when fluid with a fluid pressure that exceeds the upward force of the spring is introduced in one direction, small holes spaced vertically are formed. The plug is pushed down through a hollow piston having a hole, and the drilling fluid outlet is closed, and the fluid flow path passing through the outer flow path is made of rubber pulp with a slit provided in the hollow part of the piston, through the small hole, and on the side of the pipe. A drilled hole that guides a flow path to an inner nozzle whose opening is covered, and guides the inner flow path to an outer nozzle that opens outside the inner nozzle, and simultaneously covers the opening with the slitted sillababer valve. -Relates to a ground improvement method in which excavation and chemical injection are performed alternately while installing a chemical injection monitor and measuring the electrical resistance in the ground.

The configuration of the excavation/chemical injection pipe device used in the construction method of the present invention will be specifically explained below with reference to the drawings.

FIG. 1 shows a triple tube swivel, in which two terminals 1 are provided at the head thereof and insulated from the surroundings by an insulator 12. This terminal 1 is connected by a sliding brush 4 to a rotating terminal 6 provided on the outside of an electrode spindle which is rotatable about an axis and held watertight inside the tube part, and is also connected to a rotating terminal g- A lead wire (not shown) is drawn out from the inside of the swivel and connected to a suitable connection terminal such as a cable connector at the lower end of the swivel via a cable conduit (not shown) provided at the center of the swivel shaft.

The middle tube 5 is intended to ultimately form a fluid flow path 7 between it and the swivel mantle tube 6, and its top portion forms a closed path above the fluid intake port 8. There is.

A coaxial inner tube 9 is disposed inside the middle tube 5, forming a second fluid flow path 10 between it and the middle tube 5, and the top portion of the inner tube 9 is connected to the second fluid intake port 11. also forms a closed circuit at the top.

The middle tube 5 and inner tube 9 are fitted with O-rings 16. at appropriate locations. The ends of the swivel outer tube, middle tube, and inner tube are rotatably or watertightly supported by a ball bearing 14, a U-cup 15, and an oil seal 16.
Plugs or sockets are processed for connection to heavy pipes).

It is easier to connect the cable connectors when connecting the injection pipe rod by leaving a slight margin in the length of the connecting parts at the end of the cables, such as cable connectors (not shown). Although the injection pipe rod 17 is shown, the cable conduit located at the center of the axis is omitted to simplify the drawing. Both end edges of the outer tube 18, middle tube 19, and inner tube 20 that connect the injection tube rod 17 are processed with sockets and plugs so that they can be connected to other members in a continuous manner.

FIG. 6 shows an electrode-equipped injection tube rod 22 in which an electrode 21 is provided on the outer wall of the injection tube, and the illustration of the cable conduit is omitted as in FIG. 2. In this case as well, the ends of the aux tube, middle tube, and inner tube that make up the rod are processed into sockets and plugs in the same way as in FIG. 2.

In the case of FIG. 6, one lead wire drawn out from the cable conduit passes through the middle tube and extends to the outer tube, and is connected to the electrode 21 terminal on the outer wall of the outer tube.

Figure 4 shows a state in which the piston of the drilling/chemical injection monitor 26 attached to the tip of the chemical injection pipe as described above is not pressed down (left side).
This is a cross-sectional view of the pressed down state (right side).

The upper part is connected to the middle tube plug 24 and the outer tube socket 25, respectively, by the injection tube rod 2 with an electrode.
It is designed to be connected to 2.

When the piston 26 is not pushed down in this drilling/chemical injection monitor 26, that is, when the piston 26 is not pushed down, the fluid is not passed through the inner fluid flow path 28, or the piston 26 is pushed down against the expansion force of the spring 29.
The fluid enters the fluid passage 28 under pressure that cannot push down the fluid passage 28.
, the fluid passing through the outer fluid flow path 27 is directly guided downward along the monitor axis direction, passes through the chamber 62, flows out downward from the drilling fluid spout 61, and acts as a fluid during ground excavation. .

In addition, when performing ground stabilization construction according to the design, if fluid is introduced into the inner fluid flow path 28 at a pressure higher than the expansion force of the spring 29, the piston 26 will gradually descend and the 4
All 30 close the drilling fluid spout 31 .

On the other hand, since the piston 26 has a cavity 35 on its inside and small holes 34, 36 are bored in its wall, the fluid filling the chamber 62 when the piston 26 descends It is filled with a small hole 64, a cavity 65, and a small hole 66. An inner nozzle 37 is provided at a position on the outer tube wall facing the small hole 66.

The fluid that has passed through the inner fluid flow path 28 of the piston 26 is moved along the arrow to the inner nozzle, /I
The outer nozzle 68 adjacent to /67 is reached.

The openings of the inner nozzle 67 and the outer nozzle 68 are closed by a rubber pulp 39 with a slit, but when the pressurized fluid passes through both nozzles and hits the surface of the rubber pulp 690, the slit opens and both liquids flow. While merging in a merging chamber 41 formed inside the nozzle cap 40, the ink is jetted to the outside from the opening of the nozzle camp 40.

Since the chemical injection pipe device used in the construction method of the present invention has the above-described configuration, even if chemical injection must be interrupted in the middle of the chemical injection work, the inner nozzle 67 and the outer nozzle 68 has the advantage that it immediately closes due to the restoring force of the rubber pulp, so that the two liquids do not come into contact and solidify inside the monitor, and similarly, slime does not enter from the outside and contaminate the inside of the monitor. .

The construction method of the present invention can perform the following construction using the above-mentioned equipment.

That is, first, while excavating while rotating the tube, each time (continuously) a desired depth is reached, a current with a voltage of about 6 to 12 V is applied from an external power source to terminal 1 of the swivel head. After measuring the electrical resistance of the treated ground and injecting the chemical, measure the electrical resistance again and determine the injection area based on the degree of decrease in resistance.If necessary, add to the area where the chemical has been injected. By injecting, you can ensure the completeness of the injection.When injecting into the ground, the rod is usually rotated (at this time, of course, the monitor at the end of the rod also rotates). However, when additional chemical injection is performed as a result of resistance measurement, if the area that requires additional chemical injection is small, it is possible to stop the rotation of the rod and perform construction in a specific direction. Many of the differential pressure valve type double-pipe chemical injection pipes in which the chemical injection is performed after the ground has been excavated, but in any case, once the chemical liquid has been injected, the spring type or other valve sliding part is However, the monitor used in the method of the present invention can
The chemical liquid that comes into contact with the valve is essentially the same as water, and since the chemical liquid does not solidify here, it can be repeated as many times as necessary without causing any problems to the vertical sliding of the piston. It has the following advantages.

Water may be used as the liquid to be sent out when excavating, but for example, a slow-hardening chemical solution with a long gel time of about 10 to 20 minutes can be used as the cutting medium to loosen the soil around the hole being drilled. After preliminary curing and stabilization, chemical injection, which is the original construction process, can be performed.

Furthermore, with the method of the present invention, it is possible to once drill a hole to a predetermined depth and then perform the chemical injection work while pulling the chemical injection pipe toward the ground surface. It is also possible to lower it. In this case, one leaf is always used to deal with new soil, so favorable results are likely to be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the swivel according to the present invention, and FIG.
The figure is a sectional view of the injection pipe rod, and FIG. 4 is a sectional view of the monitor. 1...Terminal, 5...Middle tube, 8...Fluid intake port, 9...Inner tube, 11...Fluid intake port, 17...Injection tube rod, 22...With electrode Injection rod, 26... piston, 60... plug, 34.
36...Small hole, 37...Inner nozzle, 68...
・Outer nozzle, 69...Rubber valve, 41...
・Merge room. Agent Patent Attorney Sanro Kimura Figure 2 Figure 3 1 17 =65-

Claims (1)

[Claims] The required number of multiple pipe swivels with electrical signal terminals, connecting rotary ronds with cable conduits arranged in multiple pipes, and connecting rotary ronds with electrodes with electrodes and cable conduits arranged on the outer wall. At least 2
When the fluid flow path for the liquid is secured and the fluid is passed only through the outer flow path, the plug is supported upward by the pushing up of the spring, and the fluid is spouted in the direction of the pipe axis from the drilling fluid outlet formed by this. When excavating the ground and introducing a fluid with a pressure higher than the pushing up force of the spring in one direction, the plug is pushed down through a hollow piston having small holes spaced apart above and below. The fluid outlet is closed and a small hole is formed in the fluid flow path passing through the outer flow path, and the fluid passes through the hollow part of the piston and the small hole to the inner nozzle, which is provided on the side of the tube and whose opening is covered with a rubber valve with a slit. A ground improvement method in which a flow path is guided, and an inner flow path is guided to an outer nozzle that opens outside the inner nozzle, and the opening is simultaneously covered with the slitted sillababer valve.