CN212154768U - Construction structure for controlling settlement of shallow-buried underground excavation large-section tunnel - Google Patents

Abstract

A construction structures for controlling shallow dark big section tunnel of digging subsides that buries. The full-section method has the advantages that the excavation surface is large, the stability of surrounding rocks is reduced, the double-side-wall pit guiding method is safe in construction, the speed is low, and the cost is high. The utility model discloses a constitution includes: four fan-shaped caverns enclose synthetic oval structure and lay in ground girder steel (2) on ground, every fan-shaped cavern outdoor all enclose and establish bearing structure, bearing structure be by setting up fan-shaped cavern outside two-layer reinforcing bar net (4) and setting two-layer the reinforcing bar net between lay a plurality of steel bar grating (3) and constitute, ground girder steel on set up a plurality of lock foot stock (1) and pass welding in steel bar grating behind the subaerial hole. The utility model discloses reduce construction risk, construction cost input and economic loss to gain technique and economic, social win-win effect.

Description

Construction structure for controlling settlement of shallow-buried underground excavation large-section tunnel

The technical field is as follows:

the utility model relates to a construction structures for controlling shallow big section tunnel of undercut of burying subsides.

Background art:

the existing construction experience and technical achievements at home and abroad show that the shallow-buried underground tunnel construction method mainly comprises a full-section method, an up-down step method, a single-side wall pit guiding method, a double-side wall pit guiding method and the like according to geological conditions and the size of an excavated tunnel face.

The full face excavation method is also called as a full face tunneling method. A construction method for excavating a section according to tunnel design and excavating in place at one time. The excavation mode mainly comprises three types: namely a new Austrian full-face excavation method, a guard plate full-face excavation method and a heading machine guard plate full-face excavation method. The method is that the cavity is excavated and formed at one time and then lined. When the surrounding rock is stable, has no collapse and block falling risk or has smaller section size, the method is suitable for full-section excavation. The method has the advantages of wide construction field, convenient slag discharging and high tunneling speed.

The bench method is a construction method in which a tunnel upper section (upper bench) is excavated, a tunnel lower section (lower bench) is excavated after the upper bench advances for a certain distance, and the upper bench and the lower bench move in parallel. According to the step length, the method can be divided into a short step, a long step, an ultrashort step (micro step) method and the like.

The single side wall pilot tunnel method is suitable for tunnels with large tunnel span, low flatness rate, poor surrounding rock, general IV-V type surrounding rock and the need of controlling the ground surface subsidence. The construction key points are as follows: 1. dividing the section into a side wall pit guide, an upper step and a lower step; 2. the width of the side wall pilot pit is not more than 0.5 times of the width of the tunnel, and the height is preferably equal to the arching line; 3. the distance between the pilot tunnel and the step is based on the principle that the pilot tunnel construction and the step construction do not interfere with each other; 4. the distance between the upper step and the lower step is drawn up according to the situation of the surrounding rock by referring to a short step method or an ultra-short step method.

The double-side-wall pilot hole method is also called a double-side-wall pilot hole method or a spectacle method. Belongs to a branch of the new Olympic method and is based on the basic principle of the new Olympic method. The cross section is generally divided into four pieces: a left side wall pilot pit, a right side wall pilot pit, upper core soil and a lower step. Pilot pit size the size of the side wall pilot pit should be determined by taking full advantage of the support effect of the step and considering mechanical equipment and construction conditions, but the width should not exceed 1/3 of the maximum span of the section, and the height should be taken as the cambering line. Therefore, the pilot tunnel can be dug and supported for the second time, a working platform does not need to be erected, and the steel support is convenient to erect manually. The distance between the pilot hole and the step is not rigidly specified, but the pilot hole construction and the step construction are not interfered generally as a principle, so that the pilot hole can be excavated in the short tunnel firstly, and then the step can be excavated. The distance between the upper step and the lower step is drawn up according to the surrounding rock condition by referring to the short step method or the ultra-short step method. The staggered distance of the left and right side guide pits is determined according to the principle that the influence of the stress redistribution of the surrounding rock caused by excavating the guide pit on one side cannot affect the guide pit on the other side.

The current common method for controlling the deformation of the stratum at the top of the tunnel mainly comprises single-row advanced small conduit grouting, double-row advanced small conduit grouting or large pipe shed grouting.

The full-section method has the advantages that the excavation surface is large, the stability of surrounding rocks is reduced, and the workload of each cycle is large. The construction method has the advantages that the number of the blocks of the excavated section is large, each block is immediately connected with the upper part rod system after being excavated, primary support is immediately applied, and each block is closed, so that deformation hardly develops during construction. The double-side-wall pit guiding method is safe in construction, but is slow in speed and high in cost. Compared with a double-side-wall pit guiding method, the large-section shallow-buried underground excavation tunnel suspension method can save about 3 ten thousand yuan per linear meter, has obvious economic benefit, is favorable for project safety to smoothly complete production, and ensures the construction period.

At present, the common method for controlling the deformation of the stratum at the top of the tunnel mainly comprises single-row advanced small conduit grouting, double-row advanced small conduit grouting or large pipe shed grouting. No matter which advance support mode is adopted, the ground surface has settlement deformation of different degrees during the construction of the shallow tunnel. Meanwhile, due to factors such as tunnel construction management looseness, non-standard technological operation and the like, the actual ground surface settlement deformation far exceeds the design control standard. The utility model discloses the utility model of this worker method is favorable to solving the shallow big section tunnel construction of undercut of burying and arousing the earth's surface and subside deformation and control technological problem.

The utility model has the following contents:

the utility model aims at providing a construction structures for controlling shallow big section tunnel of undercut subsides that buries.

The above purpose is realized by the following technical scheme:

the utility model provides a construction structures for controlling shallow big section tunnel of undercut subsides that buries, characterized by: a construction structures for controlling shallow big section tunnel of secretly digging that buries subsides include that four fan-shaped caverns enclose synthetic oval structure and lay the ground girder steel on ground, every fan-shaped cavern outdoor all enclose and establish bearing structure, bearing structure be by setting up fan-shaped cavern outside two-layer reinforcing bar net and setting two-layer reinforcing bar net between lay a plurality of steel bar grating and constitute, the ground girder steel on set up a plurality of lock foot stock and pass welding in steel bar grating behind the subaerial hole.

The ground steel beam is a structure formed by vertically and crossly welding a transverse steel beam and a longitudinal steel beam.

The construction structure for controlling settlement of the shallow-buried underground excavation large-section tunnel is characterized in that the foot locking anchor rod comprises two steel plates arranged in parallel and a rib plate welded between the two steel plates, one end of the finish-rolled deformed steel bar penetrates through the two steel plates and is in threaded connection with a nut, and a corrugated pipe is sleeved outside the other end of the finish-rolled deformed steel bar.

The construction structure for controlling settlement of the shallow-buried underground excavation large-section tunnel is characterized in that the steel bar grating comprises a plurality of parallel stirrups arranged side by side, a plurality of main reinforcements are arranged at four corners inside the stirrups in a penetrating mode and welded, and two adjacent main reinforcements are welded through connecting reinforcements.

Has the advantages that:

1. the utility model discloses a reduce the earth's surface and subside and warp, adopt the suspension to carry out the construction of shallow big section tunnel of undercut of burying, the suspension is based on the worker's method that the double-side wall pilot tunnel method improves, set up the tie beam at the earth's surface before the tunnel excavation, and reserve drilling on the tie beam, use tie beam drilling to the direction to stratum depths predrilling, in time erect grid bow member or shaped steel bow member behind the tunnel excavation, and be connected the bow member with finish rolling screw-thread steel or prestressed anchorage cable through reserving drilling with the bow member and tie beam, thereby in time apply the earth's surface subside deformation that the big section tunnel excavation arouses.

The utility model discloses the suspension method is to the improvement of two lateral walls pilot tunnel method construction methods, and the earth's surface that can control big section tunnel construction effectively arouses subsides and warp, guarantees that peripheral existing pipeline and building (structure) can not take place to subside the incident that warp the great result in because of the earth's surface.

The utility model discloses suspension mechanics principle is clear, and construction process is simple, and maneuverability is strong, and its research of using in the shallow undercut tunnel construction settlement control that buries of big section is feasible.

The utility model discloses reduce construction risk, construction cost input and economic loss to gain technique and economic, social win-win effect.

Description of the drawings:

FIG. 1 is a schematic structural diagram of the present invention;

FIG. 2 is a schematic structural view of a ground steel beam;

FIG. 3 is a schematic structural view of a steel bar grating;

FIG. 4 is an expanded view of the reinforcement grid;

FIG. 5 is a schematic structural view of a foot-locking anchor rod;

FIG. 6 is a schematic structural diagram of construction and pavement of ground steel beams and foot locking anchor rods;

FIG. 7 is a schematic structural diagram of a construction setting advanced small guide pipe;

FIG. 8 is a schematic structural diagram of a No. 1 cavern for construction and excavation;

FIG. 9 is a schematic structural diagram of excavation of No. 2 cavern and No. 3 cavern;

FIG. 10 is a schematic structural diagram of a No. 4 cavern for construction and excavation;

FIG. 11 is a schematic view of the construction of part A secondary lining;

FIG. 12 is a schematic view of the construction of a secondary lining for the part B;

FIG. 13 is a schematic structural view with the support structure removed;

in the figure: 1. locking the anchor rod; 2. a ground steel beam; 3. a steel bar grating; 4. a reinforcing mesh; 5. a number 1 cavern; 6. a No. 2 cavern; 7. a No. 4 cavern; 8. a No. 3 cavern; 9. a longitudinal steel beam; 10. a transverse steel beam; 11. finish rolling the deformed steel bar; 12. a bellows; 13. a steel plate; 14. a rib plate; 15. a base plate; 16. a nut; 17. connecting ribs; 18. a main rib; 19. hooping; 20. leading the small catheter.

The specific implementation mode is as follows:

example 1:

the utility model provides a construction structures for controlling shallow big section tunnel of undercut of burying subsides, a construction structures for controlling shallow big section tunnel of undercut of burying subsides include that four fan-shaped caverns enclose synthetic oval structure and lay at the ground girder steel 2 on ground, every fan-shaped cavern outside all enclose and establish bearing structure, bearing structure be by setting up fan-shaped cavern outside two-layer reinforcing bar net 4 and setting two-layer the reinforcing bar net between lay a plurality of steel bar grating 3 and constitute, the ground girder steel on set up a plurality of lock foot stock 1 and pass welding in steel bar grating after the subaerial hole.

Example 2:

according to the construction structure for controlling the settlement of the shallow-buried underground excavation large-section tunnel in the embodiment 1, the ground steel beam is a structure formed by vertically and crosswise welding the transverse steel beam 9 and the longitudinal steel beam 9.

Example 3:

according to embodiment 1 or 2, the construction structure for controlling settlement of the shallow-buried underground excavation large-section tunnel comprises two steel plates 13 arranged in parallel and a ribbed plate 14 welded between the two steel plates, one end of finish-rolled deformed steel bar 11 penetrates through the two steel plates and is in threaded connection with a nut 16, and a corrugated pipe 12 is sleeved outside the other end of the finish-rolled deformed steel bar.

Example 4:

according to embodiment 1 or 2 or 3, the construction structure for controlling the settlement of the shallow-buried underground excavation large-section tunnel comprises a plurality of stirrups 19 which are arranged in parallel, main reinforcements 18 are arranged at four corners inside the stirrups in a penetrating mode and welded, and connecting reinforcements 17 are welded between every two adjacent main reinforcements.

Example 5:

a construction method of a construction structure for controlling settlement of a shallow-buried underground excavation large-section tunnel comprises the following steps:

(1) constructing a ground surface concrete cross beam and a steel longitudinal beam, and reserving tie rod holes on the tie beams;

(2) constructing a ground beam, burying finish rolling deformed steel bars, arranging small tunnel arch conduit pipes 20, arranging one row of grids every two trusses, drilling holes in a staggered mode at the interval of 100 plus slab 200mm on the pipe wall, controlling the grouting pressure to be 0.4-0.6MPa, controlling the diameter of a grouting body to be not less than 0.5m, and arranging a grout stop plug at an orifice to prevent grout from leaking;

(3) before a secondary lining structure is constructed, phi 42 water gas pipes are pre-embedded in the vault and the side wall during primary support construction, the annular distance is 3m, the longitudinal distance is 3m, the primary support is arranged in a quincunx shape, the grouting depth is 0.5m behind the primary support, cement slurry is injected after the primary support is closed to a certain length, and the grouting pressure is 0.4-0.6 MPa;

(4) when the second lining is molded, phi 42 water gas pipes are pre-embedded in the vault and the side wall, the annular distance is 3m, the longitudinal distance is 3m, the second lining is arranged in a quincunx shape, high-strength non-shrinkage slurry is injected after the second lining is pressed, and the grouting pressure is 0.1-0.3 MPa;

(5) excavating a No. 1 chamber, constructing primary support, arranging a foot locking anchor rod, connecting a primary support structure and finish-rolled deformed steel bars;

(6) excavating a cavity No. 2 and a cavity No. 3, constructing primary support, constructing a grouting anchor pipe, connecting a primary support structure and finish-rolled deformed steel, wherein the longitudinal step distance between the cavity No. 1 and the cavity No. 2 and between the cavity No. 2 and the cavity No. 3 is not less than 15 m;

(7) excavating a No. 4 chamber, and constructing primary support, wherein the longitudinal step distance between the No. 3 chamber and the No. 4 chamber is not less than 15 m;

(8) grouting from the grouting anchor pipe into the supporting structure;

(9) according to the division of the demolition section, applying prestress to finish-rolled deformed steel bars in batches, then demolishing a lower part of a temporary middle partition wall, demolishing for one time, wherein the demolition length is not more than 8m, leveling, paving a waterproof layer, finally performing secondary lining on a bottom plate of the part A and a part of side walls, and after the arch bottom structure reaches the design strength, back-supporting the temporary middle partition wall to the structural bottom plate;

(10) the temporary facing arch and the middle partition wall are broken in sections, the length of one-time breaking is not more than 8m, a B part side wall is subjected to secondary lining, and a ring is formed in a closed mode;

(11) and after the two liners reach the designed strength, removing all temporary supporting members.

Claims (4)

1. The utility model provides a construction structures for controlling shallow big section tunnel of undercut subsides that buries, characterized by: a construction structures for controlling shallow big section tunnel of secretly digging that buries subsides include that four fan-shaped caverns enclose synthetic oval structure and lay the ground girder steel on ground, every fan-shaped cavern outdoor all enclose and establish bearing structure, bearing structure be by setting up fan-shaped cavern outside two-layer reinforcing bar net and setting two-layer reinforcing bar net between lay a plurality of steel bar grating and constitute, the ground girder steel on set up a plurality of lock foot stock and pass welding in steel bar grating behind the subaerial hole.

2. The construction structure for controlling the settlement of the shallow-buried underground excavated large-section tunnel according to claim 1, which is characterized in that: the ground steel beam is a structure formed by vertically and crossly welding a transverse steel beam and a longitudinal steel beam.

3. The construction structure for controlling the settlement of the shallow-buried underground excavated large-section tunnel according to claim 2, wherein: the foot locking anchor rod comprises two steel plates arranged in parallel and a rib plate welded between the two steel plates, one end of finish-rolled deformed steel bar penetrates through the two steel plates and is in threaded connection with a nut, and a corrugated pipe is sleeved outside the other end of the finish-rolled deformed steel bar.

4. The construction structure for controlling the settlement of the shallow-buried underground excavated large-section tunnel according to claim 3, wherein: the steel bar grating comprises a plurality of stirrups which are arranged in parallel, a plurality of main reinforcements are arranged at four corners inside the stirrups in a penetrating mode and welded, and connecting reinforcements are welded between every two adjacent main reinforcements.

Images