JP4794041B2 - How to build a tunnel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for constructing a tunnel, and more particularly to constructing a tunnel in a springy ground.
[0002]
[Prior art]
As is well known, the NATM method is used to excavate a tunnel formed in a rock like a mountain tunnel. When water stoppage is required even during construction with the NATM method, when the face reaches the springy ground, preparatory work such as injecting a waterstop to the front of the face is performed to stop the water. There is a need.
[0003]
[Problems to be solved by the invention]
In such a case, it is necessary to stop the progress of the face and introduce a boring machine into the tunnel to perform drilling and water blocking agent injection from the vicinity of the face to the front of the face. In this method, the number of boring machines that can be installed on the working face is limited, and therefore, the construction period is greatly delayed, the construction becomes extremely complicated, and there is a problem in terms of cost.
[0004]
The present invention has been made in view of the above circumstances, and it is a short construction period compared with a springy natural ground or a soft ground, and a quick stop is performed without increasing the complexity of construction. It is an object of the present invention to provide a method that can be constructed.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
In other words, the tunnel construction method according to claim 1 includes a small tunnel construction step in which a small tunnel having a smaller cross section than a design cross section of the completed tunnel is preliminarily constructed and penetrated through a natural ground where the completed tunnel is to be installed , after the tunnel construction process, he said from the small tunnel, an improved construction in parallel with the row Uchiyama improved process, and the natural ground improvement process on the natural ground of the outside of the building object position of the peripheral wall surface of the finished tunnel And a completed tunnel construction step of constructing the completed tunnel by sequentially excavating the inside of the ground where the improvement work has been performed, and widening the small tunnel, The injection device of the improvement material is installed outside one of the wellheads of the small tunnel, using one end connected to the injection device and the other end side inserted into the small tunnel, Small tunnel In the completed tunnel construction process, the improvement material is injected into the outer ground of the construction target position of the peripheral wall surface of the completed tunnel sequentially from the other wellhead of the other tunnel. It is characterized by excavation of natural ground from one well to one well .
[0006]
With such a configuration, when the small tunnel is widened, the ground has already been improved, so the face can always be stabilized, and it is necessary to stop the face and stop the water. There is no.
[0008]
With such a configuration, the improvement work and the widening of the small tunnel can be performed simultaneously.
[0009]
The tunnel construction method according to claim 2 is the tunnel construction method according to claim 1 , wherein in the ground improvement process, the improvement work is a water stop work, and the improvement material injection device is It is a water material injection facility .
[0010]
This makes it possible to cope well with springy ground.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view during construction of a tunnel (completed tunnel) 1 to which a construction method according to an embodiment of the present invention is applied. This tunnel 1 is formed in the natural ground G including the spring ground, and is formed by widening the small tunnel 2 after constructing the small tunnel 2 as an advanced tunnel. . Hereinafter, the details of the construction procedure of the tunnel 1 will be described.
[0018]
In order to construct the tunnel 1, as shown in FIG. 2, first, a small tunnel 2 is formed for the natural ground G to be installed. The small tunnel 2 has a smaller cross section than the design cross section of the completed tunnel 1 and is constructed using a shield type tunnel boring machine 3. Here, when a springy ground is encountered during excavation of the small tunnel 2, a segment lining for water stoppage is performed so that the water system of the ground is not changed.
[0019]
Then, as shown in FIG. 3, when excavation of the small tunnel 2 is finished, as shown in FIG. ... and through these holes 4, 4,..., A pipe or the like is used to inject a water-stopping agent from the external injection equipment 5 toward the inside of the natural ground G. In this case, the injection target portion 6 of the water-stopping agent is the portion outside the peripheral wall surface 1a of the completed tunnel 1 to be constructed. Thereby, the natural ground G outside the construction target position of the peripheral wall surface 1a of the completed tunnel 1 is improved with water stoppage. Further, in this case, the water-stopping agent is injected only into the place where the spring water is confirmed when drilling the holes 4, 4,..., And the water-stopping agent is not injected into the place where the spring water is not confirmed. .
[0020]
Then, as shown in FIG. 4, when the water stop improvement is completed over a predetermined distance along the small tunnel 2, as shown in FIG. 1, as shown in FIG. The small tunnel 2 is widened by excavating the inside of the portion 7 improved in water stoppage. Thereby, a tunnel having the same cross section as the completed tunnel 1 is formed from one end side of the small tunnel 2. In this case, the NATM construction method is used for widening the small tunnel 2.
[0021]
Then, as shown in FIG. 5, the water stop improvement and the widening of the small tunnel 2 proceed simultaneously in a certain direction, and the water stop improvement of the natural ground G along all the small tunnels 2 as shown in FIG. 7 is completed, and the widening excavation of the small tunnel 2 is further advanced, whereby the completed tunnel 1 can be constructed in the natural ground G as shown in FIG.
[0022]
In the construction method of the tunnel 1 described above, a small tunnel 2 having a smaller cross section than the design cross section of the completed tunnel 1 is constructed in advance on a natural ground G on which the completed tunnel 1 is to be installed. Since the improvement work is performed on the natural ground G outside the construction target position of the peripheral wall 1a and then the small tunnel 2 is widened to form the completed tunnel 1, the small tunnel 2 is widened. Sometimes, the excavation target part of the natural ground G can be left in a state of being stopped in advance. As a result, the face can always be stabilized during excavation of the completed tunnel 1, and unlike the prior art, there is no need to stop the face and perform water stop work. Therefore, the construction period can be significantly shortened as compared with the conventional case, and the construction procedure can be simplified, thereby contributing to cost reduction.
[0023]
Moreover, according to the construction method of the tunnel 1 described above, the improvement work from the small tunnel 2 toward the natural ground G is sequentially performed in a certain direction along the small tunnel 2, and at the same time, the natural ground G is applied to the subsequent portion. Since the small tunnel 2 is widened by excavating, the improvement work and the widening of the small tunnel 2 can be performed simultaneously, and the construction period can be further shortened. it can.
[0024]
Moreover, in the construction method of the above-mentioned tunnel 1, since the water stop improvement was performed as the improvement construction to the natural ground G, the rapid construction of the tunnel 1 in the springy ground can be made possible.
[0025]
Furthermore, in this case, when water stop improvement is performed, holes are formed from the small tunnel 2 toward the natural ground G to form the hole portions 4, 4,..., And the spring water from the hole portions 4, 4,. Only when it was confirmed, since the water-stopping agent was injected into the natural ground G through the hole 4, the water-stopping work for the portion that is not the springy natural ground can be omitted, shortening the construction period and reducing the cost. It can contribute to reduction.
[0026]
In addition, since the small tunnel 2 is constructed by the tunnel boring machine 3, the small tunnel 2 can be constructed quickly. Especially, in the spring ground where the shield type tunnel boring machine 3 is used. This can be dealt with by performing segment lining, and there are few restrictions on ground conditions.
[0027]
Furthermore, when the small tunnel 2 is widened, the NATM method is used, so that the small tunnel 2 can be widened economically and quickly. As a result, it is possible to contribute to reduction of the construction period and cost reduction. In addition, since the NATM construction method can be applied to the ground where it has been difficult to apply the NATM construction method, the applicability of the NATM construction method can be increased.
[0028]
In the above embodiment, other configurations may be adopted without departing from the spirit of the present invention.
For example, in the above-described embodiment, the tunnel 1 is constructed in the natural ground G including the springy natural ground. However, the present invention is not limited to this, and the construction method of the tunnel 1 as described above is a soft natural ground. You may make it apply when constructing the tunnel 1 with respect to the natural ground G containing. In this case, for example, a curing agent or the like may be injected instead of the water stop agent.
Moreover, in the said embodiment, although the water stop improvement of the natural ground G and the widening of the small tunnel 2 were performed from the one end side of the small tunnel 2, not only this but these are carried out of the small tunnel 2 You may make it carry out simultaneously from both ends.
[0029]
【The invention's effect】
As described above, in the tunnel construction method according to claim 1, a small tunnel construction in which a small tunnel having a smaller cross section than the design cross section of the completed tunnel is pre-constructed and penetrated to a natural ground where the completed tunnel is to be installed. a step, after the small tunnel construction process, from the small tunnel, and rows Uchiyama improved process improvements construction against natural ground outside the building object position of the peripheral wall surface of the finished tunnel, the natural ground In parallel with the improvement step, the tunnel is constructed by sequentially excavating the inside of the ground where the improvement work has been performed, and widening the small tunnel to build the completed tunnel, and In the natural ground improvement process, an improvement material injection device is installed outside one of the wellheads of the small tunnel, one end is connected to the injection device, and the other end is inserted into the small tunnel use Then, the improvement material is sequentially injected from the other wellhead of the small tunnel toward one of the wellheads to the outer ground of the construction target position of the peripheral wall surface of the completed tunnel. Since natural ground excavation is performed from the other wellhead of the small tunnel toward one of the wellheads, when the small tunnel is widened, the excavation site of the natural ground is already improved in advance. be able to. As a result, the face can be kept stable at all times, and there is no need to stop the face and perform water stop work. In addition, the number of machines that improve ground in the preceding small tunnel can be set in any direction along the extension of the small tunnel, so the number of machines to be installed should be determined appropriately according to the capacity of widening the small tunnel. That's fine. Therefore, there is no waiting for construction of widening excavation for improvement, and it is possible to significantly shorten the construction period and to simplify the construction procedure, thereby reducing costs. Can contribute.
[0030]
Moreover, the improvement construction and the widening of the small tunnel can be performed simultaneously, and the construction period can be further shortened.
[0031]
According to the tunnel construction method according to claim 2 , in the natural ground improvement process, the improvement work is a water stop work, and the improvement material injection device is a water stop material injection facility. Rapid construction of tunnels in natural mountains can be made possible.
[0032]
Further , according to the tunnel construction method according to the embodiment of the present invention, when improving the water stoppage, a hole is formed by drilling from a small tunnel toward a natural ground, and spring water from the hole is formed. Only when it was confirmed, the water-stopping agent was injected into the natural ground through the hole, so it was possible to omit the water-stopping work on the part that was not a springy natural ground, shortening the construction period and reducing the cost. Can contribute.
[0033]
Further , according to the tunnel construction method according to the embodiment of the present invention, since the small tunnel is constructed by the tunnel boring machine, the small tunnel can be rapidly constructed. In this case, the shield type tunnel boring is also performed. If a machine is used, it can be dealt with by carrying out segment lining even in springy ground, so it is highly applicable to ground conditions.
[0034]
Further , according to the tunnel construction method according to the embodiment of the present invention , the NATM method is used when widening a small tunnel, so that the widening of the small tunnel can be performed economically and quickly. As a result, it is possible to contribute to reduction of the construction period and cost reduction. Furthermore, since it is possible to apply the NATM construction method to the ground where it has been difficult to apply the NATM construction method, the applicability of the NATM construction method can be increased.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an embodiment of the present invention, and is a sectional elevation view showing a state of the next step of FIG. 4 in a tunnel in the middle of construction.
FIG. 2 is a process diagram showing a tunnel construction method according to an embodiment of the present invention, and is a sectional elevation view showing a situation when a small tunnel is constructed on a natural ground.
FIG. 3 is a diagram showing the next step of FIG. 2 and is an elevational sectional view showing a state in which the construction of the small tunnel is completed.
4 is a view showing the next step of FIG. 3, and is an elevational sectional view showing a situation when water stop improvement is sequentially performed from one end side of a small tunnel toward a natural mountain. FIG.
FIG. 5 is a view showing the next step of FIG. 1 and is an elevational sectional view showing a state when further excavation of a portion of the natural ground where water stoppage has been improved further proceeds.
6 is an elevational sectional view showing a next process of FIG. 5; FIG.
FIG. 7 is a diagram showing the next step of FIG. 6 and is an elevational sectional view showing a state when the construction of the tunnel is completed.
[Explanation of symbols]
1 tunnel (completed tunnel)
1a Perimeter wall 2 Small tunnel 3 Tunnel boring machine 4 Hole G Jiyama

Claims (2)

A small tunnel construction process in which a small tunnel having a smaller cross section than the design cross section of the completed tunnel is preliminarily constructed and penetrated to a natural ground where the completed tunnel is to be installed ;
After the small tunnel construction process, from the small tunnel, and rows Uchiyama improved process improvements construction against natural ground outside the building object position of the peripheral wall surface of the finished tunnel,
In parallel with the natural ground improvement step, a completed tunnel construction step of excavating the inside of the portion of the natural ground where the improvement work has been performed, and widening the small tunnel to construct the complete tunnel, Prepared,
In the natural ground improvement process, an improvement material injection device is installed outside one of the wellheads of the small tunnel, one end is connected to the injection device, and the other end is inserted into the small tunnel. Using a pipe, the improvement material is injected into the outer ground of the construction target position of the peripheral wall surface of the completed tunnel sequentially from the other wellhead of the small tunnel toward one wellhead,
In the completed tunnel construction step, a tunnel construction method is characterized in that a natural ground is excavated from the other wellhead of the small tunnel to one wellhead . A tunnel construction method according to claim 1,
In the natural ground improvement process, the improvement construction is a water stop construction, and the improvement material injection device is a water stop material injection facility .

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