JP3421949B2 - 3 hinge buried tunnel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a three-hinge buried tunnel.

[0002]

2. Description of the Related Art Conventionally, a buried type three hinge tunnel is used for an underground crossing an embankment type road, a culvert crossing a river embankment, and the like. In order to construct such a buried tunnel, for example, as shown in FIGS. 4 and 5, a pair of independent foundations 1 extending in the tunnel axial direction is provided at the bottom of the ground to be buried.
Or, after installing the integrated invert foundation 4, a method of assembling the tunnel wall member 2 so as to straddle between the foundations 1 to form a tunnel wall body, and then applying the embankment 3 over the tunnel wall body is generally adopted. It has been implemented. The upper end 21 of the wall members 2 and 2 of the tunnel is hinged, and the lower end 22 is hingedly supported by the groove 11 provided in a part of the foundation. That is, the 3 hinge buried tunnel is
It is a statically fixed structure.

[0003]

However, if the supporting ground on which the foundation 1 rests is relatively soft and the ground bearing capacity is not sufficient, the independent foundation 1 may suffer large settlement or uneven settlement. If the size of the independent foundation is increased to prevent this, the bearing capacity can be obtained, but the large dimensions may induce the inclination of the foundation. Further, in the independent foundation, since the horizontal force of the 3-hinge buried tunnel is resisted by friction between the bottom surface of the foundation 1 and the supporting ground, in soft ground where sufficient slip resistance cannot be obtained,
The foundation 1 may be displaced in the horizontal direction. Conventionally, in such a case, for example, as shown in FIG. 4, the base 1 is composed of an integrated invert foundation 4 to increase the supporting area of the supporting ground to obtain a ground bearing, Is shared by the pulling force of the invert foundation. Also,
In some cases, techniques such as ground improvement and pile foundation are used for reinforcement. However, even if the invert foundation 4 is adopted, the invert foundation 4 must resist a large bending moat generated from the reaction force due to the load of the 3-hinge buried tunnel and the tensile force acting on the invert foundation 3.
The structure of the foundation becomes large-scale and complicated, and there are difficulties in its workability, economy and the like.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and can be applied to relatively soft ground, and can be constructed efficiently and economically.
It is an object to provide a hinge buried tunnel.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a gate-shaped tunnel constructed by connecting the upper ends of a pair of plate members having a folded line or a curved shape by hinges. A three hinge buried tunnel comprising a wall and a foundation for hingedly supporting a lower end of the tunnel wall, the foundation including a base extending inward and outward of the tunnel wall, and an outer base end. A three-hinge buried tunnel of an independent basic type, wherein a wall slab extending in the tunnel axial direction crossing the base slab at an appropriate position is integrally formed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a three-hinge buried tunnel according to the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

<A> Overall Configuration FIG. 1 shows an embodiment in which the present invention is applied to an arched tunnel 1. The arched tunnel 1 is composed of a pair of arcuate plates 2 and 2 assembled in an arch shape, and independent foundations 3 and 3 which transmit the load applied by the pair of arcuate plates 2 and 2 to a supporting ground 6.

<B> Arc Plate Each arc plate 2 is composed of a precast reinforced concrete plate manufactured at a site or a factory. Also, its upper end 2
In FIG. 3A, a three-hinge arch type tunnel is formed by connecting the concrete arc plates 2 and 2 with a hinge 21 and supporting the lower end 2b of the concrete arc plate 2 and the foundation 3 so as to allow a rotational displacement.

<C> Foundation As shown in FIGS. 1 and 2, each foundation 3 is composed of a base plate 5 extending inside and outside the tunnel wall and a wall plate 4 in the tunnel axial direction crossing the base plate 5. Create a substantially L-shaped shape. Supplementally, the base plate 5 having the projecting portions 51 and 52 formed in the horizontal direction is integrally formed so as to protrude to both sides of the lower portion of the wall plate 4, that is, inside and outside the tunnel wall. A vertical projecting portion 53 is provided on the upper surface of the horizontal overhanging portion 51 inside the tunnel wall, and a groove 54 is formed between the vertical projecting portion 53 and the wall plate 4. The lower end 2b of the arc plate 2 is brought into contact with and engaged with the groove 54. And
Rotational displacement is allowed while restraining lateral displacement of the lower end 2b.

[0010] As described above, the weight of the arched tunnel 1 and the load thereon are transmitted to the supporting ground 6 via the foundation 3. That is, vertical load V is supported by the vertical ground reaction force q _V acting on the base plate 5 and the wall plate 4, the horizontal load H is horizontal subgrade reaction acting on the sides of the back and the base plate 5 of the wall plate 4 Force q _H
And the frictional force of the bottom surface of the base plate 5, and the sectional force of the foundation generated by these loads is balanced with the distribution shape of the ground reaction force acting on the base plate 5 and the wall plate 4 ( (Fig. 3). Hereinafter, this will be described in detail.

As shown in FIG. 3, the acting force P (vertical force V, horizontal force H) of the fulcrum O is balanced by the ground reaction forces q _V and q _H due to the rigid displacement of the foundation 3. Ground reaction force shown, the base plate _{5 (q V1, q V2)} , the vertical elastic spring (k _V), the wall plate _{4 (q H1, q H 2} ), a horizontal resilient spring (k _H) is This is the type of reaction force considered to be on the ground. In such a case, the balance equation can be expressed as follows. In addition, in FIG. 3A, since it has the overhang portion 52,
The vertical reaction force is shared by the base plates 5 (51 and 52), and the horizontal reaction force is shared by the wall slab 4, thereby simplifying the structural analysis. In the configuration in which the wall slab 4 is inclined as shown in FIG. 3 (c), b2 is provided in b2 as shown in FIG. 3 (d).
The oblique length of the wall slab 4 on the base plate 5 may be applied. At this time,
The wall slab 4 shares not only a horizontal reaction force but also a vertical reaction force.

[0012]

(Equation 1)

Here, b ₁ , b ₂ , and h each represent a master 5
And the height of the wall slab 4 on the inside and outside of the tunnel wall.

If the foundation 3 is rotated counterclockwise by the angle α due to the ground reaction forces q _V and q _H , the elastic spring coefficients k _V (base plate 5) and k _H (wall plate 4) Thus, the following equation is obtained.

[0015]

(Equation 2)

By expanding the equations 1 and 2, q _V1 , q _V2 , q _H1 , q
_By rearranging _H2 and tanα, the following equations 3, 4, and 5 are obtained.

[0017]

(Equation 3)

[0018]

(Equation 4)

[0019]

(Equation 5)

As a special case, for example, when the ground is good, or when the ground is weak and it is required to make the settlement displacement of the base 5 uniform, the base 5
Equation 6 is set so that the reaction force becomes a uniform load distribution.

[0021]

(Equation 6)

By substituting Equation 6 into Equations 3, 4, and 5, the following Equation 7 is obtained.

[0023]

Equation 7

That is, the foundation 3 is settled equally and also displaced equally in the horizontal direction. By rearranging b ₁ , b ₂ , and h using Equation 6, the following Equation 8 is obtained.

[0025]

(Equation 8)

The vertical load V, if given horizontal load H, Formula 1, Formula 6, by Equation 7, q _V supporting ground, because it is possible to determine the q _H, by Equation 8, b _1, b ₂ , h
Can be easily determined. It is also possible to set the cross angle β of the wall slab 4 with respect to the base plate 5 (FIG. 3).
(B), (d)).

On the other hand, in the case where the ground is soft, in order to make the reaction forces q _V1 and q _V2 of the base plate 5 match the ground support force of the base plate 5 with respect to the vertical load V, Dimensions of plate 5,
That is, if the lengths b ₁ and b ₂ of the overhang portion are set as shown in Expression 9 with respect to the span 1 of the three-hinge buried tunnel, that is, the total length of the base plate 5 is reduced to half of the span of the tunnel. In this case, the average stress of the reaction force acting on the base plate 5 is equal to the average vertical stress of the vertical load V on the span of the tunnel, and the foundation 3 opposes the vertical load V of the tunnel regardless of the ground conditions. It becomes possible.

[0028]

[Equation 9]

By substituting the above relational expressions into Expressions 3, 4, and 5, the following Expression 10 is obtained.

[0030]

(Equation 10)

From equation (10), if the vertical load V, the horizontal load H, and the elastic spring coefficients k _V and k _{H of the} supporting ground are given,
By appropriately setting the dimensions of the wall slab 4 and the intersection angles (l (b _{1 ,} b ₂ ), h, β) of the wall slab 4 with respect to the base plate 5, the reaction forces q _V1 , q _V2 , q _H1 , q with and _{H 2} smaller than bearing capacity, the rotation angle of the basic 3 (tan [alpha) it can be seen that to a small value that does not hinder the practical. Further, in Expression 10, when tan α is negative, it means that the base 5 is inclined downward toward the center of the span of the tunnel.

As shown in Equation 9, b ₁ and b ₂ can be set to 1/4 or less of the span 1 of the three-hinge buried tunnel, respectively. As a result, the sectional force such as bending moment can be reduced, and the plate thickness of the base plate 5 can be reduced (see FIG. 4). Further, the wall slab 4 also helps to equalize the distribution of vertical stress generated in the base slab 5 by resisting the horizontal reaction force, thereby preventing uneven settlement and preventing a stable foundation form as an independent foundation. Is provided. And, with this basic form, the height of the inner space of the buried tunnel can be reduced to a necessary minimum.

The foundation 3 can be produced directly at the construction site as a cast-in-place RC structure, but can be supplied as a precast version of an RC secondary product depending on the construction circumstances.
In this case, if the projecting portion of the base plate 5 to the outside of the tunnel wall is omitted and the shape shown in FIG.

[0034]

As described above, the present invention can stably support a 3-hinge buried tunnel on an independent foundation having a base plate and a wall plate even in a relatively soft ground, that is, the vertical load can be reduced. The slab is mainly supported by vertical ground reaction force, and the horizontal load mainly supports the horizontal ground reaction force acting on the back of the wall slab, and the reaction force is suppressed by the support area and the moment generated by these reaction forces As well as adjusting the displacement of the foundation by adjusting the distribution of the ground reaction force acting on the base and wall slabs, not only making the foundation thinner and more stable, but also independent As a basis, the structure is simplified, shortening the construction period and reducing the construction cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an arched three-hinge buried tunnel according to the present invention.

FIG. 2 is an explanatory view of a foundation according to the present invention.

FIG. 3 is a conceptual diagram showing a configuration of a foundation and a load acting thereon.

FIG. 4 is an explanatory view of a conventional arched three-hinge buried tunnel;

FIG. 5 is an explanatory diagram of a ramen-type three-hinge buried tunnel according to the related art.

Continuation of front page (56) References JP-A-9-228399 (JP, A) JP-A-11-323974 (JP, A) JP-A 7-150898 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) E02D 29/045-29/055

Claims (4)

(57) [Claims] 1. A gate-shaped tunnel wall assembled by connecting hinges between upper ends of a pair of plate members having a folding line or a curved shape, and a foundation supporting a lower end of the tunnel wall with a hinge. A hinge buried tunnel, wherein the foundation is of an independent foundation type, a base plate extending inward and outward of the tunnel wall, and a tunnel axial direction crossing the base plate at an appropriate position including an outer base plate end And a wall slab extending inwardly, and water generated at a lower end of the tunnel wall is formed.
The flat load is mainly the horizontal ground reaction force acting on the back of the wall slab.
A three-hinge buried tunnel, characterized by being supported by: Wherein said group version, the length of the inner projecting portion of the tunnel wall, characterized by comprising the following one quarter of the span of the tunnel, 3 hinge buried tunnel according to claim 1 . Wherein the group version, the length of the overhang portion of the outer tunnel wall, characterized by comprising one following quarter of the span of the tunnel, according to claim 1 or claim 2 3 hinge buried tunnel. Wherein said underlying, cross angle with respect to ground reaction force acting on said wall plate and the base plate is the dimension of group version and wall plate to be less than bearing capacity of the supporting ground and wall plate of the base plate The three-hinge buried tunnel according to any one of claims 1 to 3, characterized in that: