JPH11193689A - Underground cavity construction method and underground cavity construction thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground cavity constructing method, capable of ensuring safe and low-cost construction in a soft ground by making working pits around an underground cavity before drilled and constructed to reinforce the ground, and provide the underground cavity. SOLUTION: In a construction method, a plurality of working pits are basically constructed outside a cavity-planed ground with a safe and reliable shield machine and a reinforcing soil zone is formed through the working pits along the vicinity of a cavity to drill a predetermined cavity by using a low-cost mountain tunnel technique. The working pits on reinforcement-necessary sides are refilled if required, the working pits are only refilled for reinforcement without forming the reinforcing soil zone or the working pits are utilized as drain pits 18 if the underground cavity should be reinforced with bolts suspended from the working pits or the underground cavity 15 should be constructed in an aquifer. The working pits are connected to the underground cavity after work is completed to construct the integrated underground cavity to be served as effective pits for ventilation 16, evacuation 17 or others.

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 cavity and an underground cavity constructed by the method, and more particularly to a method for safe and inexpensive even on soft ground by reinforcing the periphery before excavating the underground cavity. The present invention relates to an underground cavity construction method and an underground cavity that can be constructed.

[0002]

2. Description of the Related Art In recent years, underground utilization needs have been increasing, and various tests and experiments have been conducted in large underground cavities constructed for testing in preparation for the future. The use of underground has been attracting attention, especially for the use of a deep area of 50 to 100 m underground in an urban area, and excavation suitable for forming a cavity having a diameter of about 20 m for construction of a subway, an underground mall, a tunnel, and the like. Efforts are being made to select a law and to consider working conditions. For excavation of the above-mentioned linear structure, application of a shield method or a mountain tunnel method is generally considered.

[0003] However, the shield method has a problem in that the cost is high even if it is safe and secure. Particularly, when the above-mentioned large cavity is formed, it is not practical to manufacture a shield machine in accordance with the large cavity. That is, it is said that when the excavation diameter of the shield machine becomes large, the weight increases greatly according to the size of the diameter. In addition, production, temporary assembly, transportation, on-site assembly,
This is because manpower and costs increase rapidly in terms of on-site facilities and the like. In addition, although the mountain tunnel method is inexpensive, it has problems such as collapse of the ground and spring water, and there is also a problem that if the auxiliary method is used together, the construction period and construction cost are excessively required.

[0004]

SUMMARY OF THE INVENTION The present invention seeks to solve the problems by effectively utilizing the respective advantages while taking into account the problems of the conventional shield method and mountain tunnel method. First, use a shield machine that is safe and inexpensive to create a pit and a reinforced soil zone for underground cavity excavation work, and then try to excavate the desired underground cavity using an inexpensive mountain tunnel method It is.

[0005]

According to the present invention, a plurality of working pits are basically constructed outside a ground where a cavity is to be formed by a safe and secure shield machine, and a reinforcing soil zone is formed along the periphery of the cavity from the working pit. Is a method of constructing an underground cavity in which a predetermined cavity is excavated by using an inexpensive mountain tunnel method after the formation of the tunnel. Further, it is also considered that the work pit on the side requiring reinforcement is buried as necessary, and that the reinforcement is performed only by burying the work pit without forming a reinforced soil zone. Consideration is also given to reinforcing the underground cavities with suspension bolts from the work pit, and utilizing the work pit as a drainage pit when it is necessary to construct an underground cavity in the aquifer. further,
An underground cavity in which the working pit is connected to the underground cavity after the completion of the construction by the above-described construction method and integrated as an effective pit for ventilation, evacuation, etc. is also included in the scope of the present invention.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for constructing an underground cavity according to the present invention and an underground cavity constructed by the method will be described with reference to the drawings. The construction method shown in FIGS. 1 to 3 shows a basic method of constructing an underground cavity according to the present invention, and will be sequentially described below with reference to the drawings. FIG. 1 shows an excavation situation of a work pit which is a construction to be performed before the main construction of an underground cavity by the construction method according to the present invention. The work pit excavates a plurality of shields 3 at predetermined intervals in a peripheral portion 2 of a ground 1 where an underground cavity in an urban area is to be constructed. The inner diameter of the excavating shield machine is 3 to 3 in consideration of the workability of the construction.
About 5 m is desirable. The pitch and the number of shields to be excavated are determined according to the result of analyzing the scale of the underground cavity to be constructed and the strength of the ground by FEM analysis etc., and may not be specified because it may be only the upper part. is there.

FIG. 2 shows a construction state of ground reinforcement from the excavated work pit 3. In the reinforcement work from inside the shield, as shown in the figure, the reinforcing member 4 from each work pit 3 is constructed around the underground cavity construction ground 2 so as to reinforce it, thereby forming the reinforcing soil zone 5. One method is to alternately intersect with the reinforcing member 4 from the adjacent work pit 3 so as to complement each other. Reinforcing member 4
Examples thereof include mortar piles, steel pipes, lock bolts, and the like, but there is no limitation on adopting these as long as they have a function of establishing the purpose of use.

When the reinforced soil zone 5 is formed around the underground cavity construction ground 1, as shown in FIG. 3, the main work for constructing the underground cavity is performed. The underground cavity construction ground 1 has the reinforcing soil zone 5 formed in the ground as described above.
It becomes possible to adopt an inexpensive construction method such as the ATM construction method or mechanical excavation. In the case of the NATM method, a predetermined space 6 is divided and excavated in several steps by an ordinary method, and then concrete 7 is sprayed on the excavation surface, and the concrete 7 is
After completing the construction, complete the secondary lining. Also, in the case of mechanical excavation of a backhoe or the like, the construction can be completed by applying a normal construction method in which a predetermined excavation is performed by a machine and then lining is performed.

FIG. 4 is for introducing another example of the ground reinforcement shown in FIG. 2 described above. In the example shown in FIG. 4 (a), as shown in the figure, the reinforcing member 4 from the work pit 3 is constructed to reinforce the ground over the upper part 9 of the adjacent work pit 3 in a specific direction. This is an embodiment that can improve the performance. In another example shown in FIG. 4 (b), the reinforcing member 4 is extended from 31 of the working pits on both sides and constructed, and the reinforcing member 4 is not extended and constructed from the working pit adjacent thereto. This is still another embodiment in which the efficiency of work for reinforcing the ground over the upper part 9 of the adjacent work pit 3 with the reinforcing member can be improved.

The examples shown in FIGS. 5 to 7 introduce various embodiments of utilization development after excavation of a work pit. The example shown in FIG. 5 is an example in which the working pit 3 is used to protect the upper part of the underground cavity 6 when the ground 1 to be excavated is a soft layer in the case of the reinforcement example introduced in FIG.
This is an example in which a reinforcing shield 10 having rigidity is formed by being buried in the upper part 10 of the base member. This example can be adopted for the purpose of reducing the lining thickness when excavating an underground cavity.

The example shown in FIG. 6 is also an example in which the ground 1 to be excavated is a soft layer, and is an example in which only the work pit 3 is used to reinforce an underground cavity without constructing the reinforcing member 4. A reinforcing shield 10 having rigidity by being buried back after the construction of the underground cavity is formed above the underground cavity 6. This example can also be adopted for the purpose of reducing the lining thickness when excavating an underground cavity.

The example of FIG. 7 differs from the other examples in the reinforcing method. That is, the work pit 3 corresponding to the upper part of the underground cavity
The ground support is provided from one of the above to the lining concrete 11 of the underground cavity through the suspension bolts 12, and the work pit is not backfilled but only the work pits 3 on both sides thereof are backfilled. .

FIG. 8 shows an example in which the working pit is not used to reinforce the excavated ground, but is used when the ground for constructing the underground cavity is the aquifer 13. In this case, it is used to collect water from the aquifer 13 into the work pit 14 and then discharge the water to the outside so that no spring water is generated in the work section when promoting the excavation of the underground cavity. Is what it is.

FIG. 9 shows a completed state of the underground cavity 15 constructed by the above-described construction method introduced so far.
The working pit 3 constructed in advance around the underground cavity 15 is 1
By refilling the part, it is used as a ground reinforcement shield 10, and some working pits are constructed as an integrated underground cavity by excavating and connecting to some underground cavities without backfilling. In this case, the working pit which is not backfilled is formed as a ventilation pit 16, an evacuation pit 17 and a drain pit 18 as shown in the figure, and is associated with the underground cavity 6 and the inclined pit 19, etc., each of which is completed as an underground construction. doing. As described in detail above, the method of constructing an underground cavity according to the present invention uses a shield machine that is easy to manufacture, inexpensive, and easy to handle before constructing the underground cavity. The construction of the underground cavity is carried out by reinforcing the surrounding ground and then using the inexpensive mountain tunnel construction method. is there.

[0015]

According to the present invention, basically, a plurality of working pits are constructed outside the ground where the cavity is to be formed with a safe and secure shield machine, and a reinforcing soil zone is formed from the working pit along the periphery of the cavity. This is a method of constructing an underground cavity for excavating a predetermined cavity using a cheap mountain tunnel method. And if necessary, bury work pits on the side that needs reinforcement,
Reinforcement is only for embedding work pits and does not form a reinforced soil zone, and it is necessary to reinforce underground cavities with suspension bolts from work pits or to build underground cavities in aquifers The work pit is used as a drain pit, and after the completion of the above construction method, the work pit is connected to the underground cavity, and it is an underground cavity integrated as an effective pit for ventilation, evacuation, etc. The following various effects can be obtained. (1) The underground cavity can be constructed inexpensively and safely by the pre-formation of the reinforcing soil zone, and it can follow the cross section change. (2) It can be applied without difficulty in urban areas. (3) Reinforcement soil zone is ground condition, underground cavity size,
It can be freely selected according to groundwater conditions. (4) The working pit can be used as a pit for evacuation, drainage, ventilation, etc., and no extra space is required in the underground cavity.

[Brief description of the drawings]

Fig. 1 Construction situation diagram of working pit

FIG. 2 is a diagram showing formation of a reinforcing soil zone.

Fig. 3 Excavation drawing of the underground cavity body

FIG. 4 is another formation diagram of the reinforcing soil zone.

FIG. 5: Reinforcement diagram of work pit

FIG. 6 is a diagram showing another use of the work pit for reinforcement.

FIG. 7: Underground cavity reinforcement diagram of working pit

FIG. 8: Utilization diagram of working pit as drainage pit

Fig. 9 Underground cavity completed

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground 2 Underground cavity construction ground 3 Working pit 4 Reinforcement member 5 Reinforced soil zone 6 Space 7 Shotcrete 8 Rock bolt 10 Reinforcement shield 11 Lining concrete 12 Hanging bolt 13 Aquifer 14 Working pit 15 Underground cavity 16 Ventilation pit 17 Evacuation pit 18 Drain pit 19 Shaft pit

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Hiroshi Ishikawa 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation

Claims (6)

[Claims] 1. A plurality of working pits are constructed outside a ground formation scheduled ground by a shield machine, a reinforcing soil zone is formed from the working pits along the periphery of the cavities, and a predetermined cavity is formed by using a mountain tunnel method. How to construct the underground cavity to be excavated. 2. The method for constructing an underground cavity according to claim 1, wherein a work pit on the side requiring reinforcement is buried. 3. The method for constructing an underground cavity according to claim 1, wherein the formation of the reinforcing soil zone on the side requiring reinforcement is performed only by embedding a working pit. 4. The method for constructing an underground cavity according to claim 1, wherein the underground cavity is reinforced with a suspension bolt from a work pit. 5. The method for constructing an underground cavity according to claim 1, wherein the work pit is used as a drainage pit for an aquifer. 6. An effective pit for ventilation, evacuation, etc. by connecting a part of a work pit to an underground cavity.
5. An underground cavity constructed by the method for constructing an underground cavity according to any one of 5.