JPH10152830A - Method of examining underground of underground structure, and method of examining and repairing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To visually observe the state of the underground without boring a structure by progressing a metal pipe toward an underground structure by the application of a pipe bender, and inserting a micro television camera into the ground through the metal pipe. SOLUTION: A ground 4 is drilled to a prescribed depth by drilling water and excavation by a top bit, and a casing pipe 1 is penetrated. A pipe bender 4 is inserted and set in the resulting shaft. A metal pipe 5 is then pushed into the insert hole 4c of a die part 4b through the holder hole 4a of the pipe bender 4. The pipe 5 is bent during passing and circularly progressed in a horizontal part 5A. The top end reaches the lower end surface of a foundation 2. A television camera 8 is protruded from the top of the metal pipe 5 to project the state to a television on the ground. When a cavity 9 is confirmed, the camera 8 is recovered, and grout injection is performed by use of an injection passage. The injection is performed while extracting air from the cavity 9. Thus, an examination can be performed without having a bad effect on a structure, and a repairing can be successively performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of investigating and repairing a foundation of an underground structure such as a footing foundation, and more particularly, to examining the presence or absence of a cavity in the foundation, and depending on the result of the investigation. The present invention relates to a method for repairing the base plate following the investigation.

[0002]

2. Description of the Related Art A large earthquake that hit the southern part of Hyogo prefecture on the early morning of January 17, 1995 caused heavy damage to many concrete structures. It has been found that there is a danger of erosion and cavitation caused by the fluidization phenomenon. Investigation of the ground under the footing foundation can be performed, for example, by piercing the foundation, providing an insertion hole, and inserting a television camera under the foundation through the insertion hole.

[0003]

However, the method of perforating and investigating the footing foundation is not preferable because it may reduce the strength of the footing foundation.

An object of the present invention is to provide a survey method that allows a visual observation of the condition of an underlayer without drilling an underground structure such as a footing foundation.

Another object of the present invention is to provide an inspection and repair method which can repair the base plate after the base plate has been checked and, depending on the result of the check, subsequently to the search.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a metal pipe is formed from a vertical direction to a horizontal direction by applying a pipe bender in a lower part of a shaft excavated and formed near an outer side of an underground structure to be surveyed. While bending, the horizontal portion of the metal tube is propelled underground toward the underground structure so that the tip of the metal tube reaches the foundation of the structure, and then the metal tube is passed through the metal tube. A base plate for an underground structure, wherein a subminiature television camera is inserted into the base plate, and the presence or absence of a cavity in the base plate is determined by visually observing an image transmitted from the TV camera. According to the survey method.

In the present invention, the propulsion of the metal pipe in the horizontal direction is performed by excavating a tip bit provided at the tip of the metal pipe and drilling water spouted from the injection hole of the bit. Guided by drilling, the rotation of the tip bit and the supply of drilling water,
The distal end may be formed from the ground through a hollow flexible shaft connected to the rear end surface of the bit, and the hollow portion of the hollow shaft and the injection hole of the distal bit connected to the hollow portion may be used as an insertion path for a television camera.

Further, the horizontal portion of the metal tube can be propelled in an arc or a straight line in the ground.

If the result of the investigation according to the investigation method of the present invention reveals that there is a cavity, the foundation plate is repaired by injecting and filling grout into the cavity using a metal tube, following the above investigation. Can be done.

The grout may be injected and filled into the cavity through a hollow portion of the hollow shaft for driving the tip bit and an injection hole of the tip bit connected thereto.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 to FIG. 8 show an embodiment of an investigation method and an investigation repair method of the present invention using a circular arc propulsion system in the order of steps.

FIG. 1 schematically shows a process of setting up a casing pipe 1 and excavating a shaft 1A. The casing pipe 1 is located at a position slightly deviated outward from the underground structure to be investigated, for example, the footing foundation 2.
By drilling water drilled from the tip and drilling the tip bit, it penetrates to a predetermined depth while drilling the ground 3,
The lower end is fully open.

There is no particular problem if the penetration depth of the casing pipe 1 is slightly smaller than this, as long as it is substantially equal to the burial depth of the footing foundation 2, but it is appropriate to slightly increase the depth as shown in FIG.

It is preferable that the erected position of the casing pipe 1 is as close to the footing foundation 2 as possible. In order to avoid this, it is desirable to set an interval of at least about 1 m.

After the casing pipe 1 is built and the shaft 1A is formed therein, as shown in FIGS. 2A and 2B, the pipe bender 4 is inserted and installed in the shaft 1A.

The pipe bender 4 includes a tubular holder 4a having an outer diameter that can be inserted into the shaft 1A and a die part 4b fixed to the lower end of the holder 4a. The metal part is pushed through the die part 4b and bent. Insertion hole 4c is formed.

The insertion hole 4c is provided with a curved portion 4c ₂ of the predetermined curvature of the straight portion 4c ₁ of the holder and concentric addition to bottom to top,
Metal tube is subject to bending during the passage of the curved portion 4c _2.

As shown in FIG. 2 (b), the pipe bender 4 is positioned so that the curved portion 4c ₂ of the die portion 4c is curved toward the footing foundation 2 when inserted and installed in the shaft 1A. later, fixedly supported on the ground via a suitable support means (not shown) at the holder aerial part 4a ₁ projecting to the ground.

After the pipe bender 4 is inserted and installed in the shaft 1A, the metal pipe 5 for arc propulsion passes through the holder 4a of the pipe bender 4 as shown in FIGS.
2b, the metal tube 5 is forcibly pushed in by applying a hydraulic jack or the like into the insertion hole 4c, whereby the metal tube 5 is subjected to a bending process while passing through the insertion hole 4c as shown in FIG. An arc is propelled in the ground at the lateral portion 5A while changing the direction.

A tip bit 6 is provided at the tip of the metal tube 5 as shown in FIG. 9 for performing circular arc propulsion in the ground 2 with good directionality and smoothness. By giving rotation from the ground through 7, even if it hits a hard ground, it can easily pass through.

Further, a hollow shaft is used as the flexible shaft 7, and drilling water is injected from the injection hole 6a of the tip bit 6 through the hollow portion 7a of the shaft 7, so that the circular arc propulsion can be performed more smoothly and with good directionality. It is possible to do.

By continuing the arc propulsion of the metal tube 5, the tip 5a of the metal tube 5 eventually reaches the lower end surface of the footing foundation 2 as shown in FIG.

The position and depth of the footing foundation 2 can be known in advance by looking at the design drawings at the time of construction. Therefore, the pipe bender 4 and the footing foundation 2 which are the starting bases for arc propulsion
In the case of constructing a distance of up to 2 m, for example, it is sufficient that the minimum horizontal linear distance required for arc propulsion is about 2 to 3 m. Thus, in this case, a tube bender 4 having a radius of curvature of approximately 1.0 to 1.5 m may be applied.

The tip 5a of the metal tube 5 is
After reaching the lower end face, the rotation of the tip bit 6 and the injection of drilling water are stopped.

Next, a very small television camera 8 is provided by using a supply passage for drilling water, for example, a hollow portion 7a of a flexible shaft 7 and an injection hole 6a of a tip bit 6 connected thereto.
(Outer diameter of about 5 mm) is inserted to the tip of the tip bit 6 while being supported and fixed to the tip of the rigid flexible wire 8a, while the metal tube 5 is slightly withdrawn from the television camera 8 in a free state. As shown in FIG. 4, the television camera 8 can be made to protrude forward from the tip 5a of the metal tube 5.

Since the television camera 8 displays the situation under the footing foundation 2 on a monitor television set on the ground, the presence or absence of a cavity under the footing foundation 2 can be determined by visually observing this image. Incidentally, when there is no cavity, substantially nothing is displayed on the monitor television, but when the cavity 9 is generated as shown in the figure, the cavity 9 itself is displayed.

When there is a cavity, the width of the cavity 9 in the vertical direction can be confirmed. That is, since the tip 5a of the metal tube 5 moves on the locus of an arc when the tube 5 advances or retreats, the vertical position changes. Therefore, by moving the television camera 8 accompanying the vertical movement of the metal tube tip 5a, ,
When the occurrence of the cavity 9 is confirmed as in the illustrated embodiment in which the vertical width of the cavity 9 can be visually checked, the television camera 8 is pulled out and collected, and then the drilling water is removed as shown in FIG. By injecting grout, for example, cement milk 10 into the cavity 9 by using the injection passage, the base substrate can be restored to a state without the cavity 9.

The injection and filling of the cement milk 10
It is preferable to carry out air removal from the inside. For example, if a metal pipe (not shown) is circularly propelled to the cavity 9 by applying the same means as in FIGS. Can be used as an air vent.

After the injection and filling of the cement milk 10 into the cavity 9, the metal tube 5 is operated by, for example, a hydraulic jack while the injection and filling of the cement milk 10 is continued as shown in FIG. After the tip of the metal tube 5 reaches near the lower end of the lower end of the tube bender 4 by this extraction, the injection and filling of the cement milk is stopped, and then the extraction is continued to further remove the metal tube 5. Collect on the ground.

Further, as shown in FIG.
Pipe bender 4 is pulled out to the ground and collected.
As shown in FIG. 8, the casing pipe 1 is pulled out and collected while the cement milk 10 is injected and filled into the casing pipe 1 through the hose 11, thereby completing the investigation and the repair as shown in FIG.

In the arc propulsion system, since the television camera 8 can be moved in the vertical direction, even when the cavity 9 is small in size near the footing foundation 2 as shown in FIG. , This can be easily found and a reliable investigation is possible.

In the present invention, the horizontal portion 5 of the metal tube 5 is used.
A may be propelled in a straight line as shown in FIGS.

In the case of linear propulsion, as shown in FIGS. 10 and 11, a metal pipe 5 'may be bent at the bottom of the shaft 1A' so as to change the direction of the metal pipe 5 'from the vertical direction to the horizontal direction by 90 °. The applicable tube bender 4 'is applied.
As shown in the figure, bending rolls 4 are provided on both sides of the bent portion of the pipe.
The case where a plurality of a's are installed in parallel is shown. Other configurations have substantially no difference from the case of the arc propulsion described above.

In the case of linear propulsion, the tip 5a 'of the horizontal portion 5A' of the metal tube 5 'moves forward and backward in the horizontal direction as the tube 5' advances and retreats. It is convenient.

As shown in FIGS. 12 and 13, when the cavity 9 'is confirmed, grout, for example, cement milk 10' is injected and filled into the cavity 9 'from the tip 5a' of the metal tube 5 '. The ground can be restored to a state without voids. The injection and filling of the cement milk may be performed through the hollow portion 7a of the flexible shaft 7 and the injection hole 6a of the tip bit 6 connected thereto, as in the embodiment shown in FIGS.

On the other hand, when the occurrence of a cavity is not confirmed, as shown in FIGS.
Through the step a ′, the grout, for example, the cement milk 10 ′ can be step-injected to improve and improve the foundation.

In the present invention, it is necessary that the metal pipes 5, 5 ', especially the part to be bent, be able to withstand the bending work. For example, cold drawn steel pipes, stainless steel pipes and other copper (including alloys) ) It is preferable to use one pipe or the like. The portion not subjected to bending may be used by appropriately adding a rigid fixed-length tube.

The inner diameter of the metal tube must be large enough to insert the TV camera directly or through a hollow portion of a hollow flexible shaft for driving the bit when the bit is provided. Usually, those having a diameter of about 20 to 50 mmφ are used.

For pushing (propelling) or pulling (retreating) the metal tube, for example, a hydraulic jack is operated to reciprocate the chuck mechanism on the metal tube.
What is necessary is just to repeat repeatedly the pipe | tube restraint of the chuck mechanism and release from a tube restraint.

The present invention can be applied to the investigation of the foundation of a footing foundation and the investigation of the foundation of an underground structure.

[0042]

According to the present invention, it is possible to visually observe the condition of the foundation board through a television camera without drilling any through holes in an underground structure such as a footing foundation. The foundation can be inspected without any adverse effect on the strength of the underground structure, and depending on the result of the investigation, the foundation can be repaired following the investigation.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a shaft forming step showing an embodiment of an investigation method of an arc propulsion system according to the present invention.

FIG. 2 is a view showing steps from installation of a tube bender to insertion of a metal tube in the order of (a), (b) and (c).

FIG. 3 is a diagram showing a situation at the end of the arc propulsion of the metal tube.

FIG. 4 is a diagram showing a situation when the television camera is inserted.

FIG. 5 is a view showing a state at the time of injecting and filling cement milk into the cavity.

FIG. 6 is a drawing showing the state of pulling out and collecting the metal tube in the process (a)
It is a figure divided and shown to (b).

FIG. 7 is a diagram showing the state of filling and filling cement milk into the shaft.

FIG. 8 is a diagram showing a situation at the end of the inspection and repair.

FIG. 9 is a vertical sectional view showing a state of excavation guidance by the tip bit.

FIG. 10 is a view showing a straight propulsion type metal pipe insertion state according to the present invention.

FIG. 11 is a view showing a state in which the tip of the metal tube has reached a cavity.

FIG. 12 is a view showing a filling state of cement milk into the cavity.

FIG. 13 is a diagram showing a situation at the time of termination.

FIG. 14 is a diagram showing a situation in the middle of the ground improvement process when there is no cavity.

FIG. 15 is a diagram showing a situation at the time of termination.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing pipe 1A Vertical shaft 2 Footing foundation 3 Ground 4 Pipe bender 4a Tubular holder 4b Dice part 4c Insertion hole 5 Metal pipe 6 Tip bit 6a Injection hole 7 Flexible shaft 7a Hollow part 8 Television camera 9 Cavity 10 Cement milk 11 Hose

Claims (6)

[Claims] In a lower part of a shaft excavated near an outer side of an underground structure to be surveyed, a metal pipe is bent from a vertical direction to a horizontal direction by applying a pipe bender. The protruding part of the metal tube is pushed toward the underground structure in the ground so that the tip of the metal tube reaches the base plate of the structure. A method for investigating an underlayer of an underground structure, comprising: inserting a camera and visually observing an image transmitted from the television camera to determine the presence or absence of a cavity in the underlayer. 2. The underground propulsion of the horizontal portion of the metal tube,
The drill is guided by drilling of a tip bit provided at the tip of the metal pipe and drilling water spouted from the injection hole of the bit. 3. The investigation according to claim 2, wherein the inspection is performed from the ground through a hollow flexible shaft connected to a rear end face, and a hollow portion of the hollow shaft and a nozzle hole of a tip bit connected to the hollow portion are used as an insertion passage of a television camera. Method. 3. The inspection method according to claim 1, wherein the lateral portion of the metal tube is propelled in an arc shape under the ground. 4. The investigation method according to claim 1, wherein the metal pipe is propelled linearly under the ground in a horizontal direction. 5. As a result of a survey according to the survey method described in claim 1, when it is determined that there is a cavity, grout is injected and filled into the cavity by using the metal tube following the survey. Characteristic investigation and repair method. 6. If the inspection according to the inspection method according to claim 2 reveals that there is a cavity, the inspection is continued through the hollow portion of the hollow shaft and the injection hole of the tip bit connected thereto. An investigation and repair method characterized by injecting grout into a cavity.