JP2002357079A - Method for executing underground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propel an underground structure, preventing an adverse effect on a track and a rod by the movement of a friction cutting member when an underpass is constructed by burying a pipe roof, in which the friction cutting member is disposed on a top face and which is composed of a plurality of parallel pipes, between both-side shafts under the track and the road and propelling and burying the underground structure along the underside of the friction cutting member, pushing out the pipe roof. SOLUTION: The top faces of the underground structures E to be buried on the starting shaft B side and the rear end section of the friction cutting member 2 are connected by an adjusting jack 4 while the rear end section of the friction cutting member 2 and unmoved sections in the upper sections of the underground structures are connected previously by a stroke sensor 5. The adjusting jack 4 is shrunk and the friction cutting member 2 is pulled back to the original place side before the movement of the friction cutting member 2 is detected by the stroke sensor 5 and the quantity of the detection reaches a tolerance value or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground structure that crosses a road or a rail immediately below the road or a rail.

[0002]

2. Description of the Related Art As a method of constructing an underground structure serving as an underpass directly under a road or a rail, a conventional underground structure E to be built is installed on both sides of a rail or a road A as shown in FIG. After the starting shaft B and the reaching shaft C are excavated, the pipes 1 each having a rectangular cross section having the friction cut member 2 disposed on the upper surface from the starting shaft B toward the reaching shaft C are press-fitted in parallel. To form a pipe roof P having a width substantially equal to the width of the upper floor portion e of the underground structure E to be buried. Thereafter, the rear end of the friction cut member 2 is fixed to the starting shaft B side, and By extending the propulsion jack 3 supporting the reaction force on the rear wall surface of the starting shaft B in a state where the front end surface of the upper floor portion e of the ready-made underground structure E is in contact with the rear end surface of the roof P, and The ground in front of the underground structure E The underground structure E is propelled along the lower surface of the friction cut member 2 while being excavated and removed by the cutting edge F attached to the opening, and the pipe roof P pushed out to the arrival shaft C side by this propulsion is cut off. A method of constructing a tunnel by replacing a pipe roof P with an underground structure E is known.

In such a tunnel construction method,
The rear end of the friction cut member 2 is fixed to the start shaft B as described above so that the friction cut member 2 does not move to the arrival shaft due to the propulsion of the pipe roof P or the underground structure E. As shown in FIG. 6, the front end of a fixing member H such as a wire rope is integrally connected to a connecting member 6 fixed to the rear end of the friction cut member 2, and the rear end of the fixing member H is connected to a starting shaft. B, and a fixed member H 'is fixed on the rear end of the friction cut member as shown in FIG. 7, and the fixed member H' is fixed to the front wall surface of the starting shaft B. It has a structure that is received at the top.

[0004]

However, even when the fixing means H, H 'as described above is adopted, when the pipe roof P and the underground structure E are propelled along the lower surface of the friction cut member 2, Pipe roof P and underground structure E
The frictional force between the upper surface of the shaft and the lower surface of the friction cut member 2 causes the fixing means H to be pulled by the former fixing means H, so that the rear wall surface of the starting shaft B supporting the rear end of the fixing means H moves forward. The friction cutting member 2 is moved forward while being displaced. According to the latter fixing means H ′, the fixing member H ′ displaces the friction cutting member 2 forward while displacing the front wall surface of the starting shaft B forward. Will be moved.

Therefore, no matter which fixing means is employed,
The movement of the friction cut member 2 cannot be prevented, and when the friction cut member 2 moves, there is a problem that the ground above the friction cut member 2 moves integrally and adversely affects rails and roads on the ground surface side. . Such a problem similarly occurs in the method of propelling the underground structure E by pulling it from the reaching shaft C side as shown in FIG.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and its object is to not only prevent collapse of the front and rear wall surfaces on the starting shaft side, but also to prevent rails and roads on the ground surface from being damaged. It is an object of the present invention to provide a method for constructing an underground structure capable of constructing an underground structure without adverse effects.

[0007]

In order to achieve the above-mentioned object, a method for constructing an underground structure according to the present invention comprises, as described in claim 1, a friction cut member on a top surface immediately below a road or a track. A pipe roof is formed by embedding a plurality of arranged rectangular pipes in parallel, and then the upper floor of the underground structure is made to follow the pipe roof, and the friction cut member is cut while excavating the ground below the pipe roof. In a construction method of an underground structure in which the underground structure is replaced with a pipe roof and an underground structure portion by propelling the underground structure along the lower surface of the friction cut member while being left, the friction cut member is promoted by the pipe roof. When moving in the front-back direction, the friction cut member is moved and adjusted to the original position side by the expansion / contraction means. .

According to a second aspect of the present invention, in the method for constructing an underground structure according to the first aspect, the expansion and contraction means includes a front end and a rear end of a friction cut member and an upper surface of the underground structure or a spacer member. It is characterized by comprising an adjustment jack detachably connected to the upper surface. Furthermore, the invention according to claim 3 is that, in the method for constructing an underground structure according to claim 1, a detecting means for detecting a movement amount of the friction cut member is disposed on a propulsion side of the underground structure. It is characterized by.

Further, in the method for constructing an underground structure according to any one of claims 1 to 3, the invention according to claim 4 is characterized in that the detecting means comprises: A stroke sensor connected to an immovable part on the propulsion side of the object, and when the underground structure is propelled, the adjusting jack is in a no-load state and the pressing force is not applied to the friction cut member, and the underground structure is not acted on. The rod of the adjusting jack is extended in accordance with the propulsion of the underground structure, the amount of movement of the friction cut member generated by the propulsion of the underground structure is detected by the stroke sensor, and the adjusting jack is operated in accordance with the detected amount to operate the friction cut member. Is moved and adjusted to the original position side.

[0010]

A plurality of rectangular cross-section pipes having substantially the same size and the same shape as the upper surface are mounted on the upper surface. To form a pipe roof having a width substantially equal to the width of the upper floor of the underground structure. The friction cut members placed on the upper surfaces of the pipes have their front ends integrally fixed to the front ends of the respective pipes when the pipes are buried, and are separated after the burial. In addition, in order to prevent collapse of the ground on both sides when burying an underground structure at both end sides of the pipe roof, it is desirable to arrange buried pipes side by side.

After forming the pipe roof in this way, an existing underground structure is disposed on the starting shaft side, and the front end surface of the upper floor portion is joined to the rear end surface of the pipe roof in a state of being abutted. Alternatively, the pipe roof is buried in the ground by pushing the pipe roof along the lower surface of the friction cut member toward the reaching shaft side by being propelled forward by the traction means. At this time, in order to excavate the ground in front of the underground structure, a cutting edge for excavating the ground below the pipe roof is mounted on the front end surface of the underground structure in advance, and the ground in front is excavated by the cutting edge. The excavated earth and sand is discharged to the starting shaft through the underground structure.

When the underground structure is propelled forward along with the pipe roof along the lower surface of the friction cut member, the friction cut member slides the upper surface of the pipe roof and the underground structure on the smooth lower surface, and the pipe roof is moved. While moving the underground structure forward, the frictional force of the sliding contact surface causes the underground structure to move forward. In this way, when the friction cut member moves forward due to the propulsion of the underground structure, the friction cut member is moved by the expansion / contraction means before the amount of movement of the friction cut member becomes an amount that affects the rail or road on the ground surface side. It is pulled backward by an amount substantially corresponding to the amount of movement, and moved to the original burying position side.

Each time the friction cut member reaches a movement amount that does not affect the rail or road on the ground surface as the underground structure is propelled, the expansion / contraction means is operated to adjust the movement to the original position side. The underground structure is replaced with a pipe roof, and the underground structure is buried up to the arrival shaft. The expansion / contraction means may be constantly biased in the direction in which the friction cut member is pulled back, so that the friction cut member is hardly moved against the sliding force generated by the promotion of the underground structure or the pipe roof. It can be maintained at the substantially original position, and even if the friction cut member moves, the movement can be easily adjusted to the original position side by the expansion and contraction means.

[0014] The expansion and contraction means may include, for example,
As described in the above paragraph, an adjustment jack is used in which the front and rear ends are integrally connected to the rear end of the friction cut member and the upper surface of the underground structure, respectively. As described in Item 4, a stroke sensor is used in which the front and rear ends are connected to the front end of the jack and an immovable part on the propulsion side of the underground structure, for example, a beam erected between both side walls of the starting shaft. Is preferred.

When the underground structure is propelled, the adjusting jack has a hydraulic circuit in a neutral state, that is, a state in which both sides of the piston are unloaded so that the hydraulic circuit can freely expand and contract, and has a length equal to the amount of propulsion of the underground structure. Extend the rod. As described above by the propulsion of the underground structure, when the friction cut member moves in the propulsion direction due to the frictional force (sliding force) with the pipe roof or the upper surface of the underground structure, the stroke bar of the stroke sensor is moved by the amount of movement. It extends to detect the amount of movement of the friction cut member. Before this movement amount reaches the amount that affects the rails and roads on the ground surface, the adjustment jack is operated in the contraction direction to move the friction cut member to the substantially original position, that is, the detection amount of the stroke sensor is substantially reduced. Pull back to zero position.

Next, the underground structure is propelled and buried again, and when the friction cut member moves during that time, the amount of movement is detected by the stroke sensor, and the friction cut member is restored by the adjustment jack in the same manner as described above. The underground structure is buried while being returned to the position side so that the movement of the friction cut member does not affect the rail or road on the ground surface side. When the underground structure is propelled, the adjusting jack is in a no-load state.However, a load equal to or less than the propulsive force of the propelling jack may be applied to the adjusting jack in a direction in which the rod contracts. In this case, the movement of the friction cut member can be prevented by the adjustment jack, and the friction cut member can be maintained at the substantially original position. Even if the friction cut member moves forward by overcoming the contraction force of the adjustment jack, the adjustment can be performed. By operating the jack in the contracting direction, the jack can be easily moved and adjusted to the original position.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention;
Starting shaft B on both sides of the ground (hereinafter referred to as road A)
And the arrival shaft C is excavated. If the road A is high and there are wide spaces on both sides of the road A via the slope, one side may be the starting side and the other side may be the arrival side.
Next, a pipe roof P is formed by embedding a plurality of rectangular pipes 1 with the cross-sections on which the friction cut members 2 are mounted on the ground D under the road between the starting shaft B and the reaching shaft C in a parallel state.

As is known, the pipe roof P is formed by, for example, pressing the pipe 1 horizontally into the ground D under the road so as to cross the road A from the starting shaft B toward the reaching shaft C. After being buried in the ground between the starting shaft B and the reaching shaft C, the next pipe 1 is press-fitted in parallel using the side surface of the pipe 1 as a guide, and this operation is repeatedly performed to repeat the road A.
The pipe roof P having a predetermined width in the length direction is formed. The pipe 1 is press-fitted while an earth auger (not shown) is inserted into the hollow to excavate and remove the ground in front.

The friction cut member 2 mounted on the upper surface of the pipe 1 is made of a flat strip-shaped steel plate having substantially the same size and shape as the upper surface of the pipe 1, and the front end thereof is formed of the pipe 1.
After being press-fitted in a state where it is integrally fixed to the front end of the upper surface by welding or the like and reaching the reaching shaft C, it is cut off from the front end of the pipe 1 and the fixing to the pipe 1 is released. If the buried length of the pipe roof P is longer than the length of one pipe 1, the next pipe 1 is press-fitted while being connected in series to the pipe 1 having a fixed length. In this case, the front end of the friction cut member 2 mounted on the pipe 1 is fixed only to the leading end, that is, only the tip end of the pipe 1 reaching the arrival shaft C side, and the friction cut member on the next pipe 1 is fixed. 2 has its front end integrated with the rear end of the friction cut member 2 on the preceding pipe 1 by welding or the like. Also,
As shown in FIG. 2, a plurality of overhanging pipes 1 ′ are press-fitted and buried in parallel on both sides of the pipe roof P as necessary, and the overhanging pipes are used to bury the underground structure E when buried. Prevents ground collapse.

Further, the rear end of the friction cut member 2 projects rearward from the front wall of the starting shaft B without being fixed to the rear wall or the front wall of the starting shaft B by fixing means. Therefore, since the fixing means is not provided, the preparation for burying the underground structure E can be efficiently performed.
As before, the friction cut member 2 may be fixed to the starting shaft B using a wire rope or a turnbuckle.

After the pipe roof P is formed in the ground under the road between the starting shaft B and the reaching shaft C, the thickness of the upper floor e in the starting shaft B is slightly smaller than the thickness of the pipe roof P. A prefabricated underground structure E having a width substantially equal to that of the pipe roof P is installed, and a front end surface of the upper floor portion e is subjected to a friction cut in which the upper surface of the upper floor portion e is placed on the pipe roof P. The pipe 2 is joined to the rear end face of the pipe roof P so as to be in contact with the lower surface of the rear end portion of the member 2 and a plurality of propulsion jacks 3 are interposed between the rear end face of the underground structure E and the rear end face of the starting shaft B. .

The underground structure E is provided with a cutting edge F for excavating the ground on the lower surface side of the pipe roof P at the front end opening, and a position adjusting mechanism G for the friction cut member 2 on the upper surface side. Have been.

The position adjusting mechanism G of the friction cut member 2 comprises expansion / contraction means including an adjustment jack 4 and detection means including a stroke sensor 5, and the adjustment jack 4 is provided with an underground structure in its length direction. As shown in FIG. 3, the front end of the rod 4a is fixed to the rear end of the friction cut member 2 projecting from the starting shaft B as shown in FIG. It is joined or detachably connected to the connecting member 6, and the rear end of the cylinder portion 5b is connected to the rear end of the underground structure E or the intermediate portion in the longitudinal direction, or not shown, but behind the underground structure E. It is detachably connected to a support member 7 detachably fixed to a spacer member interposed between the end face and the propulsion jack 3. The connecting member 6 is made of a rectangular bar that is long in the width direction of the pipe roof P, and the lower surface thereof is fixed to the upper surface of all the friction cut members 2 that constitute the pipe roof P, so that all of the friction cut members 2 are fixed. Are connected integrally.

On the other hand, a stroke sensor 5 as a detecting means
The stroke rod 5a is detachably connected to and supported by the cylinder 5b and is fixed to a stationary part 8 formed of a beam which is fixed between both side walls of the starting shaft B. The stroke rod 5a projects elastically from the cylinder 5b. The front end is detachably connected to a projecting piece 6a projecting from the upper surface of the connecting member 6.

The position adjusting mechanism G thus configured
May be provided only at a central portion in the width direction of the underground structure E, but a plurality of position adjustment mechanisms G are provided at predetermined intervals in the width direction of the underground structure E. By arranging the position adjusting mechanisms G at a plurality of positions in the width direction between the friction cut member 2 and the underground structure E in this manner, it is possible to increase the amount of movement of the underground structure E in the front-rear direction. Even when the underground structure E tilts to the side, the displacement can be detected and the position can be corrected.
The adjusting jack 4 is configured to measure the stroke amount (shrinkage amount) of the rod 4a by an appropriate measuring device (not shown).

After arranging the plurality of position adjusting mechanisms G on the upper surface side of the underground structure E as described above, when the rod of the propulsion jack 3 is extended, the underground structure E frictionally contacts the upper surface of the upper floor portion e. While sliding against the lower surface of the cutting member 2 and excavating the ground in front by the cutting edge F, the vehicle moves forward,
The pipe roof P is also pushed forward at the front end face of the upper floor e of the underground structure E, and slides on the lower surface of the friction cut member 2 to project its front end toward the arrival shaft C according to the amount of forward movement of the underground structure E. Let it. When the pipe roof P projecting toward the arrival shaft C reaches a certain length, the projecting portion of each pipe 1 is cut off and removed. The earth and sand excavated by the cutting edge F is discharged and removed through the underground structure E into the starting shaft B at the rear.

When the underground structure E is pressed into the ground and propelled by extending the rod of the propulsion jack 3, the adjustment jack 4 in the position adjustment mechanism G is set in a neutral state, that is, in a no-load state, and the rod is free. To be able to expand and contract. Therefore, when the underground structure E is pushed into the ground, it contracts by a length equal to the propulsion amount of the underground structure E, and the pipe roof P reaches the underground structure E integrally with the underground structure E by the propulsion of the underground structure E. Move to the shaft C side.

The movement of the underground structure E and the pipe roof P is performed using the friction cut member 2 as a guide while sliding the upper surface against the lower surface of the friction cut member 2. Due to the frictional force (sliding force) between the underground structure E and the upper surface of the pipe roof P, the underground structure E and the pipe roof P slip the friction cut member 2 forward with respect to the lower surface of the friction cut member 2. To slide.

When the friction cut member 2 moves,
The stroke bar 5a of the stroke sensor 5 supported by the immovable portion 8 extends by a length equal to the amount of movement, and detects the amount of extension (extension length) by the stroke sensor 5 and is installed on the starting shaft B side. Is input electrically to the adjusted control unit (not shown). Before the underground structure E is completely pushed into the ground, when the amount of movement of the friction cut member 2 reaches the maximum allowable limit which does not affect the rails on the ground surface or the road A, the adjustment is performed. A signal is sent from the control unit to the adjusting jack 4 to supply pressure oil to the adjusting jack 4 in the direction in which the rod 4a contracts, and the rod 4a is contracted by a length substantially equal to the above-mentioned set amount. The frictional cut member 2 is pulled back backward by taking a reaction force to E, and returned to the original embedding position. The position adjustment of the friction cut member 2 by the adjustment jack 4 may be performed while the underground structure E is being propelled by the propulsion jack 3, or may be performed while the propulsion of the underground structure E is stopped. Good.

Thus, the underground structure E is buried in a penetrating state between the starting shaft B and the reaching shaft C. The length between the starting shaft B and the reaching shaft C, that is, the underground structure E is formed. When the length of the underground passage is long, the underground structure E, which is obtained by dividing the underpass in the length direction, is pushed forward by the propulsion jack 3 while sequentially joining and connecting the underground structures E in series back and forth. When the rod 4a of the adjusting jack 4 cannot be further contracted by the propulsion of the underground structure E, the support member 7 connecting and supporting the rear end of the adjusting jack 4 is moved to the upper surface of the underground structure E. And the cylinder portion 4b of the adjusting jack 4 is moved backward while extending the rod 4a with the connecting member 6 of the friction cut member 2 as a fulcrum, and is moved to a position where the rod 4a is extended to the maximum. The upper surface of the underground structures E, or to fix the support member 7 on the upper surface of the spacer member.

In this case, if the extension amount of the rod 4a of the adjustment jack 4 is equal to the length of one underground structure E,
When a series of underground structures E are propelled and buried by the length of one underground structure E, the support member 7 is moved to the upper surface of the underground structure E on the rear side or the upper surface of the spacer member, and the rod is moved. What is necessary is just to fix it with 4a extended to the maximum,
If the extension amount of the rod 4a of the adjusting jack 4 is a length obtained by dividing the length of one underground structure E into several parts, every time the rod 4a contracts to the use limit, the support member 7 is moved backward by the contraction amount. The position may be changed and the rod 4a may be extended to the maximum, and fixed to the upper surface of the underground structure E or the upper surface of the spacer member.

Next, a method for adjusting the position of the friction cut member 2 will be described in detail with reference to the flowchart of FIG. In this description, the adjusting jack 4 has a length such that its rod 4a can expand and contract by an amount corresponding to the length of one underground structure E. First, when promoting the start of the underground construction E is advance by measuring the initial value S ₀ of the stroke amount of the stroke sensor 5 with keep this adjustment jack 4 in the unloaded state. After a while
The rod of the propulsion jack 3 is extended to push the underground structure E into the ground, propelling while excavating the ground in front along the lower surface of the friction cut member 2, and moving the pipe roof P toward the reaching shaft C side. Extrude according to.
At this time, the rod 4a of the adjusting jack 4 contracts by the same amount as the propulsion amount of the underground structure E, and the contraction amount (stroke) L
Is measured.

[0033] As described above by promoting the underground structures E, the friction cutting member 2 is moved, the amount of movement is measured by the stroke sensor 5, the measured quantity (measured value) above from S ₁ initial measured value S _{The value} after subtracting ₀ is
If it is below the allowable value that does not affect the rail or the road A (usually about 3 mm), the propulsion and burial of the underground structure E is continued. When the length of one underground structure E is propelled and buried in this state, the pushing of the underground structure E by the propulsion jack 4 is stopped, and the next underground structure E is inserted into the underground structure E. And the underground structure E is propelled again.

On the other hand, when the measured amount S ₁ -initial value S ₀ of the friction cut member 2 becomes 3 mm or more while the underground structure E is being pushed by the length of one, the adjusting jack 4 is moved to the rod 4a. Is actuated by applying a load in the contracting direction to take a reaction force on the underground structure E to draw the friction cut member 2 rearward. The amount of pulling is detected as the amount of contraction of the stroke bar 5a of the stroke sensor 5, and the measured value S ₂ −the initial value S ₀ is −2 mm or less, that is, up to + −2 mm of the length of the initial value S _0. When the friction cut member 2 is pulled rearward, the adjusting jack 4
To no-load condition again. The position adjustment of the friction cut member 2 by the adjustment jack 4 is repeatedly performed until the underground structure E is propelled by one piece underground.

As described above, when the friction cut member 2 moves forward when the underground structure E is propelled or buried, the position is adjusted by pulling it toward the original position by the adjusting jack 4. The object E may be displaced to one side due to a change in the geological condition of the front ground or the pressing force of the plurality of propulsion jacks 3. In this case, the friction cut member disposed on the other side is used. 2 moves forward, while the friction cut member 2 disposed on one side moves rearward.

Therefore, on the side where the friction cut member 2 moves forward, the position of the friction cut member 2 is moved back to the original position by the position adjusting mechanism G provided on the friction cut member 2 side as described above. Position adjustment is performed by pulling back, and on the side where the friction cut member 2 moves rearward, the friction cut member 2 is pushed forward to the original position side by the position adjustment mechanism G disposed on the friction cut member 2 side. In this way, the position is adjusted.

[0037] That is, when the friction cutting member 2 is moved rearward, the amount of shrinkage is measured as a measured quantity stroke rod 5a of the stroke sensor 5 is contracted, the measured quantity (measured value) the initial measured values from S ₁ The value obtained by subtracting S ₀ is 3 mm
If below, the propulsion and burial of underground structure E is continued and
When the distance is equal to or more than mm, the adjustment jack 4 is extended and the friction cut member 2 side disposed on one side is pushed forward toward the original position. When the amount of extension of the adjustment jack 4 reaches the initial measured value S ₀ , the adjustment jack 4 is again put in a no-load state, and the propulsion of the underground structure E is continued.

When the underground structure E is propelled, the adjusting jack 4 is in a no-load state.
At any time, a load equal to or less than the propulsion force of the propulsion jack 3 may be urged in the direction in which the rod 4a contracts, so that when the underground structure E is propelled, Even if the friction cut member 2 attempts to move forward due to the forward movement with the pipe roof P, the movement can be prevented by the adjusting jack 4, and the contraction force (load) of the adjusting jack 4 is further reduced. When the friction cut member 2 moves forward due to overcoming, the contraction force of the adjustment jack 4 is increased to adjust the position of the adjustment jack 4 to return to the original position.

In the above embodiment, the adjusting jack 4 is used as the expansion and contraction means in the position adjustment mechanism G. However, a screw mechanism or a traction means may be employed.
Further, without using the stroke sensor 5 as the detecting means, for example, on the upper surface of the friction cut member 2 protruding from the starting shaft B, the rails and the road A are affected rearward (projecting direction) from the front wall surface of the starting shaft B. A mark line is provided in the width direction at a portion having the above-mentioned allowable value (approximately 3 mm) which does not affect the entire length of the friction cut member 2 or at a desired portion such as both side portions. When the line is hidden in the front wall of the starting shaft B by the movement of the friction cutting member 2 forward, the adjusting jack 4 is contracted to move the friction cutting member 2 from the front wall of the starting shaft B to the rear. It may be configured to operate until it is exposed.

[0040]

As described above, according to the method for constructing an underground structure according to the present invention, as described in claim 1, a plurality of friction cut members having a friction cut member disposed on an upper surface immediately below a road or a track. After the pipe roof was formed by burying rectangular pipes in parallel, the upper floor of the underground structure was made to follow this pipe roof, and the ground under the pipe roof was excavated while excavating the ground below the pipe roof. In a construction method of an underground structure in which a pipe roof is replaced with an underground structure by propelling a structure along the lower surface of the friction cut member, the friction cut member may affect a road or a rail by the promotion of the pipe roof. When the friction cut member is moved back and forth by an unacceptable amount, It since characterized in,
Without causing collapse of the front and rear walls on the starting shaft side, and furthermore, the lateral movement and relaxation of the ground above the underground structure,
The underground structure can be surely constructed without preventing collapse or the like and without adversely affecting rails and roads on the ground surface.

In the above method for constructing an underground structure, the invention according to claim 2 is characterized in that the expansion and contraction means is detachably connected to the rear end of the friction cut member and the upper surface of the underground structure, respectively. When the friction cut member is moved forward by the propulsion of the underground structure, the adjustment jack is contracted before the movement amount exceeds the allowable range, so that the front and rear walls of the starting shaft are adjusted. The reaction force can be received on the underground structure side without any influence on the friction cutting member, and the friction cut member can be easily and reliably moved to the original position and adjusted.

In addition, during the propulsion of the underground structure, the adjusting jack is always urged in a direction in which the rod contracts with a load less than the propulsive force of the propelling jack, so that the friction cut member is moved forward. In addition, even if the adjustment jack is moved, the contraction force of the adjustment jack is increased, whereby the adjustment jack can be easily pulled back to the original position to perform the position adjustment.

According to the third aspect of the present invention, since the detecting means for detecting the amount of movement of the friction cut member is provided on the propulsion side of the underground structure, the friction cut member can be mounted on the road or rail on the ground surface side. The amount of movement of the friction cut member can be measured so that the friction cut member does not move beyond the allowable range, and the adjustment jack can be operated according to the amount of movement to return the friction cut member to the original position.

The detecting means comprises a stroke sensor having front and rear ends connected to a front end of the adjusting jack and an immovable part on the propulsion side of the underground structure, respectively. When the underground structure is propelled, the above adjustment jack is put in a no-load state and the underground structure is propelled without applying a pressing force to the friction cut member, and the movement amount of the friction cut member generated by the propulsion is measured by the stroke sensor. It is characterized by detecting and operating the adjustment jack according to the detected amount to move and adjust the friction cut member to the original position side, so that the adjustment jack or the adjustment jack using the upper surface of the underground structure The stroke sensor can be installed compactly and the preparation work for burying underground structures can be performed efficiently. Yes, when embedded, the stroke sensor strokes in synchronism with the amount of movement of the friction cut member, allowing accurate detection of the amount of movement easily and also allowing easy and reliable adjustment of the position of the friction cut member using the adjustment jack. It is.

[Brief description of the drawings]

FIG. 1 is a simplified longitudinal side view showing the propulsion and burial of an underground structure

FIG. 2 is a simplified longitudinal front view thereof,

FIG. 3 is a longitudinal side view of a starting shaft portion provided with a position adjusting mechanism,

FIG. 4 is a longitudinal sectional side view showing a state in which an underground structure is propelled by a certain length in the ground,

FIG. 5 is a flowchart for adjusting the position of a friction cut member.

FIG. 6 is a simplified vertical side view showing a conventional example,

FIG. 7 is a simplified vertical side view showing another conventional example,

FIG. 8 is a simplified vertical side view showing still another conventional example.

[Explanation of symbols]

 Reference Signs List A road or rail B starting shaft C reaching shaft E underground structure P pipe roof G position adjustment mechanism 1 pipe 2 friction cut member 3 propulsion jack 4 adjustment jack 5 stroke sensor 8 immovable part

Claims (4)

[Claims] 1. A pipe roof is formed by embedding a plurality of rectangular pipes having a friction cut member disposed on an upper surface thereof in parallel in a state directly below a road or a track.
The underfloor structure is propelled along the lower surface of the friction cut member with the friction cut member remaining while excavating the lower ground of the pipe roof with the upper floor portion of the underground structure following the pipe roof. In the method of constructing an underground structure for replacing a roof and an underground structure, when the friction cut member moves in the front-rear direction due to the promotion of the pipe roof, the friction cut member is moved and adjusted to the original position side by the expansion / contraction means. Characteristic construction method of underground structure. 2. The expansion / contraction means is an adjustment jack having front and rear ends connected to a rear end of a friction cut member and an upper surface of an underground structure or an upper surface of a spacer member, respectively. The method for constructing an underground structure according to item 1. 3. The underground structure construction method according to claim 1, wherein a detecting means for detecting an amount of movement of the friction cut member is provided on a propulsion side of the underground structure. 4. The detecting means comprises a stroke sensor having front and rear ends connected to a front end of the adjusting jack and an immovable portion on the propulsion side of the underground structure, respectively. The underground structure is propelled without applying a pressing force to the friction cut member in a no-load state, and the movement amount of the friction cut member generated by the propulsion is detected by the stroke sensor, and according to the detected amount, The method according to claim 1, wherein the adjusting jack is operated to move and adjust the friction cut member to the original position.