JP2002371574A - Culvert construction type tunneling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for constructing a high-strength tunnel with no structural defect while aiming at rationality, stability, and safety of works in a culvert construction type tunneling method. SOLUTION: In the culvert construction process, an inner space substantial layer 6, a culvert circumferential wall 7, and an earthen cover layer 8 outside the culvert are formed of a relatively low-strength improved soil D3, a relatively high-strength improved soil D4, and non-improved soil on the ground G respectively. In the inner excavation process, the inner space substantial layer 6 is removed and a culvert inner space part 9 is formed inside the culvert circumferential wall 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of civil engineering and relates to an improvement of a culvert construction type tunnel construction method.

[0002]

2. Description of the Related Art There is a culvert construction type tunnel construction method as one means for constructing a tunnel. According to the existing method, a culvert is prepared in advance, and the culvert is buried and buried. When a tunnel is constructed by such a method, the rigidity of the culvert must be increased because the amount of sediment at the top of the culvert and the additional load due to the strain difference of the embankment act on the culvert as a vertical load. This has caused a decrease in workability and an increase in construction costs.

The method disclosed in Japanese Patent Publication No. Hei 6-39798 has been developed as a countermeasure. In this known method, the inner space of the culvert, the surrounding wall of the culvert, the subgrade,
Embank the general part at the same time. At this time, a material reinforced with a cement-based solidifying material, lime, or the like is used for the culvert peripheral wall, and the culvert peripheral wall has an arch shape. After this, the culvert is constructed by removing the soil inside the culvert by tunnel excavation.

The above-mentioned known construction method is advantageous in terms of construction cost and workability since it is not necessary to provide a concrete wall for earth pressure support for the culvert and it is not necessary to prepare the culvert in advance.

[0005]

[Problems to be solved by the invention]
There is still room for improvement in the method of JP-A-39798. One of them is how to secure construction safety and structural stability when the ground strength is poor. This countermeasure is not found in known methods. The other is due to the simultaneous construction of the culvert wall, the subgrade, and the general section. In such a construction method, the material (earth and sand) in the inner space of the culvert is mixed into the subgrade material (reinforcement material), so that the function and strength of the subgrade decrease. For this reason, it is necessary to carry out a correction work in which the surface layer of the subgrade is shaved later and a subgrade material corresponding to the shaved portion is supplemented. Yet another is due to the formation of the layers in the culvert from soil with insufficient compressive strength. Incidentally, the layers in the culvert support the culvert peripheral wall, which is under the pressure of the covering layer, from inside for a certain period of time to prevent deformation and structural defects. Therefore, when the compressive strength of the layer is insufficient, stress concentrates on the inner peripheral surface side of the top of the culvert peripheral wall, and structural defects such as deformation and cracks are generated. The understrength of the layer also tends to cause the face to collapse when it is removed in the internal excavation process, so that it is difficult to ensure operational safety.

[0006]

SUMMARY OF THE INVENTION In view of the above technical problems, the present invention provides a method for constructing a high-strength tunnel without structural defects while maintaining the rationality, stability, and safety of work in a culvert construction type tunnel method. It is something to offer.

[0007]

The culvert construction type tunnel method according to claim 1 of the present invention is characterized by the following means for achieving the intended object. That is, the method of the present invention according to claim 1 includes a culvert construction step and an internal excavation step, and uses an improved soil and a non-improved soil during the culvert construction step, and uses a relative soil on the ground. Forming the culvert peripheral wall with improved soil of high strength, forming the inner space solid layer inside the culvert with relatively low strength soil, and forming the soil cover layer outside of the culvert with non-improved soil, and internal excavation At the time of the process, the inner cavities are removed to form inner culvert spaces in the culvert peripheral wall.

The culvert construction type tunnel method according to the second aspect of the present invention is characterized by the following means for solving the problem in order to achieve the intended purpose. That is, the construction method of the present invention described in claim 2 includes a foundation excavation step, a road body construction step, a culvert peripheral wall, an internal excavation step, and a subgrade construction step. Excavating to form an excavation groove in the excavated portion, and, in the case of a road body construction process, embedding a part of or all of the excavation groove with the improved soil and embedding a road body having a subgrade recess on the upper surface. Building at the place and filling the recess for roadbed with improved soil to form a recess filling layer, and at the time of the culvert building process, using improved soil and non-improved soil, and On the road body, the culvert peripheral wall is formed by the relatively high strength improved soil, the inner space solid layer inside the culvert is formed by the relatively low strength improved soil, and the soil cover layer outside the culvert is formed by the non-improved soil. That In the case of the internal excavation process, the concave portion filling layer and the inner space solid layer are removed to reproduce the subgrade for the subgrade and to form the inner space of the culvert, and in the subgrade construction process, the subgrade material is used. Is used to construct the subgrade in the subgrade recess.

[0009]

The culvert construction type tunnel method according to the first aspect of the present invention includes a culvert construction step and an internal excavation step. In the culvert construction step of these, the culvert peripheral wall, the inner hollow solid layer inside the culvert, and the soil covering layer outside the culvert are formed simultaneously. In this case, not only the culvert peripheral wall but also the inner hollow solid layer will be made with improved soil,
It is possible to sufficiently secure the strength of the inner layer. This strong inner hollow layer supports the culvert peripheral wall subjected to the heavy pressure of the soil cover layer from the inner side to prevent deformation and cracking of the culvert peripheral wall, so that a culvert without structural defects can be constructed. On the other hand, the inner hollow solid layer is to remove this during the internal excavation process. At this time, the strong inner space solid layer is unlikely to cause collapse of the face, so that safety in operation can be secured. Further, since the inner hollow solid layer has a lower strength than the culvert peripheral wall, it can be easily distinguished from each other, and the removal operation can be easily performed.

A culvert construction type tunnel method according to a second aspect of the present invention includes a foundation excavation step, a road body construction step, a culvert peripheral wall, an internal excavation step, and a roadbed construction step.
In the foundation excavation process, an excavation groove is formed in the ground, and in the subsequent road body construction process, the excavation groove is filled with the improved soil to construct a road body having a subgrade recess. Regarding the road body construction process, the construction of the road body by the improved soil leads to the ground improvement, and the subfloor concave portion formed on the upper surface of the road body becomes a subfloor construction space. In addition, since the recess for the roadbed is filled with the recess filling layer (improved soil), the recess for the roadbed is not deformed in the subsequent process, and foreign matter is not mixed into the recess. Therefore, these processes also contribute to the safe, accurate and stable construction of the culvert and its related parts. Since the culvert construction process and the internal excavation process in this method are substantially the same as those described above, it is possible to construct a culvert without structural defects, and to safely and easily remove the inner hollow solid layer. However, in the internal excavation process, not only is the inner hollow solid layer removed to form the inner space of the culvert,
The concave portion filling layer road is also removed to reproduce the concave portion for the subgrade.
In the subgrade construction step, the subgrade is constructed using the subgrade material in the reproduced subgrade recess.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a culvert construction type tunnel method according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 to FIG. 7 schematically show each step of an embodiment of the method of the present invention. Of these, Figure 1 is the foundation excavation process, Figure 2 is the road body construction process,
Fig. 3 shows the culvert construction process, Fig. 4 shows the internal excavation process, and Fig. 5
6 shows a lining step, FIG. 6 shows a road layer construction step, and FIG. 7 shows a secondary coating step.

In the foundation excavation step shown in FIG. 1, the ground G is excavated to form an open groove 1. Specifically, the ground G is excavated along a predetermined excavation route using a well-known excavating construction machine such as a power shovel, a bulldozer, and a carrier scraper. The cutout groove 1 formed in the ground G in this way has, for example, an isosceles trapezoidal shape whose cross-sectional shape is reversed as shown in the figure.

In the road body construction step shown in FIG. 2, the main part of the cut groove 1 is filled with the improved soil D1 to construct the road body 3 having the roadbed recess 2. The improved soil D1 in this case is, for example, a material obtained by uniformly mixing one or more of cement, lime, and coal ash with soil generated on site. This is carried into the cut groove 1 by a conveyor or the like, and the road body 3 is constructed using a well-known construction machine.
The remaining space of the cut groove 1 is filled with earth and sand, for example, soil generated on site. The backfill layer 4 is thus formed. The backfill layer 4 is on both sides of the road body 3 and fills it. In the road body construction step, the improved soil D2 is filled in the concave portion 2 for the roadbed, and the concave portion filling layer 5 is formed there. The improved soil D2 in this case is similar to the improved soil D1, but has a lower strength than the improved soil D1.

The culvert construction step shown in FIG. 3 is performed after the strength of the road body 3 has developed. The strength of the road body 3 is manifested by natural aging (curing) in which a certain period elapses after its construction. After the strength of the road body 3 has developed, FIG.
As described above, the inner hollow solid layer 6 made of the improved soil D3, the culvert peripheral wall 7 made of the improved soil D4, the primary soil layer 8 made of soil (eg, soil generated on site), and the like are simultaneously formed on the road body 3 and the ground adjacent thereto. Specifically, bulldozer scraper
Using a construction machine such as a rolling machine or a tamping machine, operations such as unwinding, leveling, and compacting are performed to form them simultaneously. The improved soils D3 and D4 used in this case are also made by mixing one or more of cement, lime, and coal ash with the soil generated on site, for example, as described above. However, the improved soil D4 is stronger than the improved soil D3.

Incidentally, regarding the strength (uniaxial compressive strength) of each of the improved soils D1 to D4, the expression D2 ≦ D3 ≦ D4 and D2
It is desirable to satisfy the following expression: ≦ D3 ≦ D1. This relationship may vary depending on the strength required for the foundation and the strength required for the culvert peripheral wall 7, but D2 and D3
Does not exceed the intensity of D1 or D4.

In the inner excavation step shown in FIG. 4, the recessed portion filling layer 5 and the inner space filling layer 6 are removed to reproduce the roadbed recessed portion 2 and to form the culvert inner space 9. Specifically, the recessed filling layer 5 and the inner layer 6 are cut off by using a well-known excavating machine, and the cut-out layers are transported to the outside by a well-known soil transportation means. In this case, the recess filling layer 5 and the inner space filling layer 6 made of the improved soils D2 and D3 described above have high safety from the viewpoint of strength.

In the lining step shown in FIG. 5, a lining layer 10 is formed on the inner surface of the culvert peripheral wall 7. The liner layer 10 is typically made of reinforced concrete (RC), but may be made of any other material such as unreinforced concrete, precast concrete, resin, or the like.

In the step of constructing a subgrade shown in FIG. 6, a subgrade 11 and a subgrade 12 are formed on the subgrade recess 2 and a pavement 13 is formed thereon. The roadbed 11 is formed of a well-known material such as crushed stone, high-quality sand, and cement processing, and the roadbed 12 is formed of a non-plastic material (known) such as crushed stone and cement processing. The pavement 13 is like asphalt pavement or concrete pavement. In this case, since the road layer construction step also forms the subgrade 11, the sublayer construction step is also included.

In the secondary embankment step shown in FIG. 7, a secondary embankment layer 14 is formed on the primary embankment layer 8. That is, the secondary embankment layer 14 is formed on the primary embankment layer 8 using a well-known construction machine. The secondary embankment layer 14 is also made of, for example, on-site generated soil. This secondary embankment process may be omitted in some cases.

FIGS. 8 to 10 schematically show the main steps of another embodiment of the method of the present invention. In this embodiment, since the culvert is constructed directly on the strong ground G, the above-described foundation excavation step and the road body construction step are not adopted. Hereinafter, this embodiment will be described.

In the culvert construction process shown in FIG. 8, on the ground G, the inner hollow solid layer 6 is formed with the improved soil D 3 and the culvert peripheral wall 7.
Is formed from the improved soil D4, and the primary covering layer 8 is formed from the non-improved soil (eg, soil generated on site).

At the time of the internal excavation step shown in FIG. 9, the inner hollow solid layer 6 is removed in the same manner as described above to form the culvert inner space 9. When forming the inner space 9 of the culvert,
Are simultaneously formed.

In the following, the lining step and the road layer construction step are performed in the same manner as described above, and the secondary embankment step similar to the above is performed as necessary. Thus, the tunnel is completed as shown in FIG.

FIGS. 11 to 12 schematically show the main steps of another embodiment of the present invention. This embodiment improves the ground G and improves the ground G
Build a culvert on top of Therefore, in this embodiment, a ground improvement step, a culvert construction step, an internal excavation step, and other steps are performed as described below.

In the ground improvement step shown in FIG. 11, the ground G is improved and strengthened by well-known ground improvement means such as compaction, forced consolidation, consolidation, and replacement. To give specific examples of consolidation and substitution,
One is the injection of cement-based modifiers and the other is concrete replacement.

After the ground G is improved, the above-described culvert construction process, internal excavation process, lining process, and road layer construction process are performed, and the above-described secondary embankment process is performed as necessary. Or Of these, in the case of the internal excavation step, not only the culvert inner space 9 but also the roadbed recess 2 are formed at the same time. Thus, the tunnel is completed as shown in FIG.

[0028]

The culvert construction tunnel method according to the present invention has the following effects.

In the culvert construction step, not only the peripheral wall of the culvert but also the inner solid layer is made of the improved soil and its strength is sufficiently ensured, so that a culvert without structural defects can be constructed.

The strong inner hollow layer is unlikely to cause collapse of the face when it is removed, so that operational safety can be ensured. Further, since the inner hollow layer has a lower strength than the culvert peripheral wall, the inner layer can be easily distinguished from each other and can be easily removed.

The ground improved in the ground improvement step can withstand the culvert load built here, and stably supports the culvert. Therefore, the subsequent steps are stably performed and the culvert is stabilized from the foundation.

The foundation excavation step and the road body construction step precede the culvert construction step. In the road body construction process, the construction of the road body with the improved soil leads to the ground improvement, and the subfloor recess formed on the upper surface of the road body serves as a subgrade construction space. In addition, since the recess for the roadbed is filled with the recess filling layer (improved soil), the recess for the roadbed is not deformed in the subsequent process, and foreign matter is not mixed in the recess. Therefore, these processes also contribute to the safe, accurate, and stable construction of the culvert and its related parts, and there is no irrationality in which correction work must be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a foundation excavation step of an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing a road body construction step of the embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically showing a culvert construction step of one embodiment of the method of the present invention.

FIG. 4 is a cross-sectional view schematically showing an internal excavation step of the embodiment of the present invention.

FIG. 5 is a cross-sectional view schematically showing a lining step of the embodiment of the method of the present invention.

FIG. 6 is a cross-sectional view schematically showing a road layer building step of the embodiment of the present invention.

FIG. 7 is a sectional view schematically showing a secondary embankment step of the embodiment of the present invention.

FIG. 8 is a cross-sectional view schematically showing a culvert construction step of another embodiment of the method of the present invention.

FIG. 9 is a cross-sectional view schematically showing an internal excavation step of another embodiment of the method of the present invention.

FIG. 10 is a sectional view schematically showing another embodiment of the present invention after the secondary embankment step.

FIG. 11 is a cross-sectional view schematically showing a ground improvement step of another embodiment of the present invention method other than the above.

FIG. 12 is a cross-sectional view schematically showing a state after the secondary embankment step in another embodiment of the present invention method.

[Explanation of symbols]

 G Ground 1 Open cut ditch 2 Subgrade recess 3 Road body (improved soil D1) 4 Backfill layer 5 Recess filling layer (improved soil D2) 6 Inner air filled layer (improved soil D3) 7 Culvert peripheral wall (improved soil D4) 8 Primary covering layer 9 Inner space of culvert 10 Lining layer 11 Subgrade 12 Subgrade 13 Pavement 14 Secondary covering layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiraoka sequentially, 4-33 Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture Chugoku Electric Power Co., Inc. (72) Kyohei Yamada 4-33, Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture Chugoku Electric Power Co., Ltd. (72) Inventor Shinichi Yoshiji 4-33 Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture Chugoku Electric Power Co., Inc. (72) Inventor Ryuji Nakamoto 4-33 Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture Chugoku Electric Power Company (72) Inventor Shigeo Matsukage 4-33, Komachi, Naka-ku, Hiroshima-shi, Hiroshima Chugoku Electric Power Co., Inc. (72) Inventor Yasuhiro Oda 4-33, Komachi, Naka-ku, Hiroshima-shi, Hiroshima Chugoku Electric Power Co., Inc. (72) Inventor Koji Ninomiya 4-9-9 Akasaka, Minato-ku, Tokyo Inside Japan Land Development Co., Ltd. (72) Inventor Kenji Mada 4-9-1-9 Akasaka, Minato-ku Tokyo, Japan Inside Japan Land Development Co. 2) Inventor Koichi Tashiro 4-9-9 Akasaka, Minato-ku, Tokyo Inside Japan Land Development Co., Ltd. (72) Inventor Takeo Takahashi 1-7-1, Kyobashi 1-chome, Chuo-ku, Tokyo Inside Todaken Construction Co., Ltd. (72) Inventor Junichi Usui 1-7-1 Kyobashi, Chuo-ku, Tokyo F-term (reference) 2D055 AA07 BA07 BB02 CA01 DA11 LA18 2D063 BA05 BA31

Claims (2)

[Claims] A culvert construction step and an internal excavation step;
Using improved soil and non-improved soil, and on the ground, further improve the culvert peripheral wall with relatively high strength improved soil, and further improve the inner hollow solid layer inside the culvert with relatively low strength improved soil. A culvert construction type tunneling method characterized by forming soil covering layers outside of the culvert with soil, and, in the case of an internal excavation process, removing an inner hollow solid layer and forming an inner space of the culvert in a culvert peripheral wall. . 2. A base digging process, a road body building process, a culvert peripheral wall, an internal digging process, and a subgrade building process. When forming a groove, and during the road body construction step, part or all of the excavated groove is filled with improved soil to build a road body with a subgrade recess on the upper surface at the embedding location, and Filling the concave portion with the improved soil to form a concave portion filling layer, and at the time of the culvert construction step, use the improved soil and the non-improved soil, and relatively on the road after the strength is developed Forming the surrounding wall of the culvert with the improved soil with high strength, forming the inner layer of the inner space inside the culvert with the improved soil with relatively low strength, and forming the overburden layer on the outer side of the culvert with non-improved soil. When is concave The filling layer and the inner layer are removed to reproduce the subgrade recess and to form the inner space of the culvert, and at the time of the subgrade construction step, the roadbed material is used to fill the subgrade recess. A culvert construction type tunnel method characterized by building a floor.