Support structure of diversion tunnel slag collecting pit

Abstract

The application discloses a supporting structure of a diversion tunnel slag collecting pit, which comprises an advanced radial grouting layer, a steel mesh layer, a shotcrete layer, a concrete lining and a plurality of radial anchor rods, and further comprises a plurality of anti-seismic connecting units, each of which comprises: a center connecting mechanism, one end of which is abutted against the surface of the steel mesh layer, and the other end of which extends into the shotcrete layer and extends out; a plurality of connecting rods, one end of each of the plurality of connecting rods is hinged to the side wall of the same center connecting mechanism, and the other end of each of the plurality of connecting rods is sleeved on the free section of a radial anchor rod; and a tension member, one side of which is fixed with the part of the center connecting mechanism extending out of the shotcrete layer, and the other side of which is pre-pressed and fixed with a steel reinforcement cage in the concrete lining. The application has the beneficial effect of improving the resistance to the vibration effect generated during blasting in the tunnel excavation process.

Description

Technical Field

[0001] This invention relates to the field of tunnel excavation technology. More specifically, this invention relates to a support structure for a slag collection pit in a water diversion tunnel. Background Technology

[0002] The main structure of this project is a water diversion tunnel, with a total length of 4390.945m and a tunnel diameter of D-2.0m. The tunnel also requires a maintenance shaft, 48.7m high, 5.87m long, and 5.20m wide. The shaft will contain an emergency gate (2.5m wide x 2.0m high) and a trash rack (2.5m wide x 2.0m high). This project also includes a permanent adit (No. 1 construction adit), 465.489m long. The geological conditions at the project site fall into two categories: one is lithic tuff, weakly weathered, with alteration along both sides of the joint surfaces. The rock is soft, with well-developed joints, mostly undulating and rough, with some areas being straight and rough or undulating and smooth, slightly open, filled with rock debris or mud, and the rock mass is relatively broken, forming a fragmented structure. The surrounding rock is unstable. Groundwater in the tunnel flows in a drip-to-linear pattern. The estimated normal inflow is 518m³. 3 / d, the surrounding rock category is IV. Another type of lithology is lithic tuff, weakly weathered, with alteration zones on both sides of the joint surfaces. The rock is soft, with well-developed joints, mostly undulating and smooth, slightly open to wide, locally reaching 10cm, filled with rock fragments or muddy material. The rock is broken to relatively broken, forming a fragmented to fractured structure. The surrounding rock is extremely unstable. The groundwater in the cavern flows linearly to inrush. The estimated maximum inrush volume is 1136 m³. 3 / d, the surrounding rock category is V. The saturated compressive strength of the two categories of lithic tuff weakly weathered rocks ranges from 31.2 to 84 MPa. They are soft rocks with heterogeneous rock quality and significant differences.

[0003] During tunnel excavation, blasting technology is also required. The vibration generated during blasting will further adversely affect the lining structure of the slag pit. Conventional support methods include wire mesh, shotcrete, anchor bolts, and concrete lining. To improve seismic performance, the conventional technique is to thicken the lining structure, but this increases the amount of reinforced concrete work and the lateral excavation span of the slag pit, thus increasing the construction difficulty of the tunnel excavation. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0005] To achieve these objectives and other advantages according to the present invention, a support structure for a slag collection pit in a water diversion tunnel is provided, comprising an advanced radial grouting layer, a steel mesh layer, a shotcrete layer, a concrete lining, and multiple radial anchors, and further comprising multiple seismic connection units, each seismic connection unit comprising:

[0006] A central connecting mechanism, one end of which abuts against the surface of the steel mesh layer, and the other end which extends into the shotcrete layer and outwards;

[0007] Multiple connecting rods, one end of which is hinged to the side wall of the same central connecting mechanism, and the other end is respectively sleeved on the free section of multiple radial anchor rods;

[0008] The tension member is fixed on one side to the part of the central connecting mechanism that extends out of the shotcrete layer, and on the other side to the pre-stressed steel cage inside the concrete lining.

[0009] Preferably, the central connecting mechanism includes:

[0010] The center rod has multiple snap-fit ​​edges spaced apart on its outer side wall, and at least one strip-shaped groove is formed on the outer side wall of the center rod;

[0011] A pair of sleeves are respectively sleeved on both ends of the central rod. Multiple snap-fit ​​grooves are spaced apart on the inner sidewall of the sleeve. At least one threaded hole is opened radially on the sidewall of the sleeve. The snap-fit ​​groove snaps into the outside of the snap-fit ​​edge. A bolt is screwed into the threaded hole, and the lower end of the bolt extends into the groove.

[0012] The central ring is movably sleeved on the central rod and located between a pair of sleeves.

[0013] Preferably, the connecting rod includes:

[0014] The telescopic rod has a pair of connecting rings at each end, one of which is hinged to the central ring;

[0015] The connecting cylinder is shaped like a small middle section and a large two ends. The connecting cylinder is sleeved on the free section of the radial anchor rod. A rotating ring is movably sleeved in the middle part of the connecting cylinder. The rotating ring is hinged to another connecting ring.

[0016] Preferably, the end of the sleeve located inside the reinforcing cage is provided with at least one pair of lugs, and the surface of the lugs is provided with an annular groove;

[0017] The tensile component includes:

[0018] At least one steel plate having at least one pair of threaded holes, a guide cylinder correspondingly provided on the surface of the steel plate facing the lug, the guide cylinder having threaded holes inside, the lug and the threaded holes being fixedly connected by bolts and nuts, and the steel plate abutting against one or more reinforcing bars of the reinforcing cage;

[0019] At least one pair of springs, the springs being sleeved inside the guide cylinder, with the other end of the springs abutting against the annular groove.

[0020] Preferably, the depth of the advanced radial grouting layer injection is greater than 2m, and the spacing and row are [not specified].

[0021] Preferably, the radial anchor bolts are longer than 1.5m, with a spacing and row spacing of 0.6 to 0.8m and a diameter of 22mm.

[0022] Preferably, the thickness of the sprayed concrete layer is 12cm.

[0023] Preferably, the number of connecting rods located on the same central connecting mechanism is 4 to 6.

[0024] The present invention offers at least the following advantages: it significantly improves resistance to vibrations generated during blasting without thickening the lining structure. Compared to existing technologies, it avoids increasing the amount of reinforced concrete work and the transverse excavation span of the slag pit, thereby reducing the difficulty of tunnel excavation.

[0025] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0026] Figure 1 This is a circumferential sectional view of the support structure according to one of the technical solutions of the present invention;

[0027] Figure 2 This is a front view of the seismic connection unit according to one of the technical solutions of the present invention;

[0028] Figure 3 This is a top view of the seismic connection unit according to one of the technical solutions of the present invention;

[0029] Figure 4 This is a detailed view of the connecting cylinder according to one of the technical solutions of the present invention;

[0030] Figure 5 This is a detailed view of the tension member according to one of the technical solutions of the present invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0032] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0033] like Figures 1-5 As shown in the attached figures, the meanings of the reference numerals are as follows: 1. Advanced radial grouting layer; 2. Steel mesh layer; 3. Shotcrete layer; 4. Concrete lining; 5. Radial anchor bolt; 6. Central connection mechanism; 7. Connecting rod; 8. Tensioning component; 61. Central rod; 62. Snap-fit ​​edge; 63. Groove; 64. Sleeve sleeve; 65. Central ring; 71. Telescopic rod body; 72. Connecting ring; 73. Connecting sleeve; 74. Rotating ring; 66. Lug; 81. Steel plate; 82. Guide cylinder; 83. Spring.

[0034] like Figures 1-5 As shown, this invention provides a support structure for a slag collection pit in a water diversion tunnel, including an advanced radial grouting layer 1, a steel mesh layer 2, a shotcrete layer 3, a concrete lining 4, and multiple radial anchors 5. The depth of the advanced radial grouting layer 1 is greater than 2m. The radial anchors 5 are longer than 1.5m, with a spacing and row spacing of 0.6-0.8m and a diameter of 22mm. The thickness of the shotcrete layer 3 is 12cm. The advanced radial grouting layer 1, steel mesh layer 2, shotcrete layer 3, concrete lining 4, and multiple radial anchors 5 are conventional support structures in the prior art and will not be described in detail here. This solution improves the existing support structure for rock types IV and V. The purpose is to enhance resistance to the vibration effects generated during blasting when using blasting technology during tunnel excavation.

[0035] Therefore, multiple seismic connection units are set, each of which includes:

[0036] The central connecting mechanism 6 has one end abutting against the surface of the steel mesh layer 2 and the other end extending into and out of the shotcrete layer 3; the central connecting mechanism 6 can establish a connection relationship between the radial anchor 5, the shotcrete layer 3, and the concrete lining 4 to resist the arc-shaped vibration wave generated during blasting.

[0037] Multiple connecting rods 7 are provided, with one end of each connecting rod 7 hinged to the side wall of the same central connecting mechanism 6, and the other end respectively fitted onto the free sections of multiple radial anchor rods 5. Since during blasting excavation, holes are usually pre-embedded according to the pre-calculated number, diameter, location, and amount of explosives, and then ignited for blasting, the resulting shock waves are multi-point overlapping and mixed. Therefore, multiple connecting rods 7 are set to connect to the same central connecting mechanism 6 to resist the shock waves that are enhanced by multi-point overlapping and mixed.

[0038] Since the spacing and row spacing of the radial anchor bolts 5 are both 0.6 to 0.8 m, the number of connecting rods 7 located on the same central connecting mechanism 6 is preferably 4 to 6. If there are fewer than 4, although the vibration resistance is good, the construction time and cost will increase. If there are more than 6, the vibration resistance is insufficient, especially for rock types of surrounding rock categories IV and V.

[0039] The tension member 8 is fixed on one side to the portion of the central connecting mechanism 6 extending out of the shotcrete layer 3, and on the other side to the reinforcing cage within the concrete lining 4. During construction, the central connecting mechanism 6, connecting rod 7, etc., need to be installed and fixed to the reinforcing cage before concrete is poured. Since the central connecting mechanism 6, connecting rod 7, etc., are prone to displacement during concrete pouring, the tension member 8 is provided for appropriate pre-fixation and to generate a certain pre-pressure, ensuring that the central connecting mechanism 6 abuts against the steel mesh layer 2 and the reinforcing cage.

[0040] In the above technical solution, without changing the existing commonly used support structure, a seismic connection unit is added to establish a connection between the radial anchor rod 5, the shotcrete layer 3, and the concrete lining 4, in order to resist the arc-shaped seismic waves generated during blasting. Multiple connecting rods 7 are set to connect to the same central connecting mechanism 6 to resist the seismic waves that are reinforced by multiple overlapping points. By setting the seismic connection unit, the increased workload is only a simple installation operation, without the need to thicken the lining structure, that is, without increasing the amount of reinforced concrete work or the transverse excavation span of the slag pit. This significantly reduces the construction difficulty of the tunnel excavation, improves construction efficiency, and saves construction time.

[0041] In another technical solution, the central connecting mechanism 6 includes:

[0042] The center rod 61 has multiple snap-fit ​​edges 62 spaced apart on its outer side wall, and at least one strip-shaped groove 63 is formed on the outer side wall of the center rod 61.

[0043] A pair of sleeves 64 are respectively fitted onto both ends of the central rod 61. The inner sidewall of each sleeve 64 is provided with multiple locking grooves spaced apart. At least one threaded hole is opened radially on the sidewall of each sleeve 64. The locking groove is engaged with the outside of the locking ridge 62. A bolt is screwed into the threaded hole, and the lower end of the bolt extends into the groove 63. The sleeve 64 is fitted onto the central rod 61 along the length direction of the locking ridge 62. After reaching the required length, the bolt is rotated downward along the threaded hole until the lower end of the bolt extends into the groove 63, thereby realizing the connection and fixation between the sleeve 64 and the central rod 61.

[0044] The central ring 65 is movably sleeved on the central rod 61 and located between a pair of sleeves 64.

[0045] In the above technical solution, the tunnel wall is not as smooth as the walls of ordinary furniture, and the distribution of the radial anchor bolts 5 is not as precise as the pre-calculated distances and positions, resulting in certain errors. Therefore, the connection method of the center rod 61 and the sleeve 64 is adjustable to adapt to different distances. Additionally, the center ring 65 can be adjusted to different angles.

[0046] In another technical solution, the connecting rod 7 includes:

[0047] The telescopic rod 71 has a pair of connecting rings 72 at each end, one of which is hinged to the central ring 65; the length of the telescopic rod 71 is adjustable to accommodate radial anchors 5 at different distances.

[0048] The connecting cylinder 73, which is smaller in the middle and larger at both ends, is sleeved on the free section of the radial anchor rod 5. A rotating ring 74 is movably sleeved in the middle of the connecting cylinder 73, and the rotating ring 74 is hinged to another connecting ring 72. This cylindrical sleeve design prevents the telescopic rod 71 from detaching from the radial anchor rod 5 during concrete pouring.

[0049] In another technical solution, the end of the sleeve 64 located inside the steel cage is provided with at least a pair of lugs 66, and the surface of the lugs 66 is provided with an annular groove.

[0050] The tension member 8 includes:

[0051] At least one steel plate 81 is provided with at least one pair of threaded holes. A guide cylinder 82 is provided on the surface of the steel plate 81 facing the lug 66. The guide cylinder 82 is provided with threaded holes. The lug 66 and the threaded holes are fixedly connected by bolts and nuts. The steel plate 81 abuts against one or more reinforcing bars of the reinforcing cage.

[0052] At least one pair of springs 83 are sleeved inside the guide cylinder 82, and the other end of the springs 83 abuts against the annular groove.

[0053] In the above technical solution, by setting lug 66, steel plate 81, spring 83 and pre-compressing connection and fixation with the steel cage, the central connecting mechanism 6 is pre-compressed and positioned, reducing the displacement of the central connecting mechanism 6 during concrete pouring and thus affecting its vibration resistance function.

[0054] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A support structure for a slag collection pit in a water diversion tunnel, comprising an advanced radial grouting layer, a steel mesh layer, a shotcrete layer, a concrete lining, and multiple radial anchor bolts, characterized in that, It also includes multiple seismic connection units, each of which includes: A central connecting mechanism, one end of which abuts against the surface of the steel mesh layer, and the other end which extends into the shotcrete layer and outwards; Multiple connecting rods, one end of which is hinged to the side wall of the same central connecting mechanism, and the other end is respectively sleeved on the free section of multiple radial anchor rods; The tension member is fixed on one side to the part of the central connecting mechanism that extends out of the shotcrete layer, and on the other side to the steel cage in the concrete lining for pre-compression. The central connection mechanism includes: The center rod has multiple snap-fit ​​edges spaced apart on its outer side wall, and at least one strip-shaped groove is formed on the outer side wall of the center rod; A pair of sleeves are respectively sleeved on both ends of the central rod. Multiple snap-fit ​​grooves are spaced apart on the inner sidewall of the sleeve. At least one threaded hole is opened radially on the sidewall of the sleeve. The snap-fit ​​groove snaps into the outside of the snap-fit ​​edge. A bolt is screwed into the threaded hole, and the lower end of the bolt extends into the groove. A central ring, which is movably sleeved on the central rod and located between a pair of sleeve cylinders; The connecting rod includes: The telescopic rod has a pair of connecting rings at each end, one of which is hinged to the central ring; The connecting cylinder is shaped like a small middle section and a large two ends. The connecting cylinder is sleeved on the free section of the radial anchor rod. A rotating ring is movably sleeved in the middle part of the connecting cylinder. The rotating ring is hinged to another connecting ring. The end of the sleeve located inside the steel cage is provided with at least one pair of lugs, and the surface of the lugs is provided with an annular groove. The tensile component includes: At least one steel plate having at least one pair of threaded holes, a guide cylinder correspondingly provided on the surface of the steel plate facing the lug, the guide cylinder having threaded holes inside, the lug and the threaded holes being fixedly connected by bolts and nuts, and the steel plate abutting against one or more reinforcing bars of the reinforcing cage; At least one pair of springs, the springs being sleeved inside the guide cylinder, with the other end of the springs abutting against the annular groove.

2. The support structure for the slag collection pit of the water diversion tunnel as described in claim 1, characterized in that, The depth of the advanced radial grouting layer injection is greater than 2 m, with spacing and rows.

3. The support structure for the slag collection pit of the water diversion tunnel as described in claim 1, characterized in that, The radial anchor bolts are longer than 1.5 m, with a spacing and row spacing of 0.6~0.8 m and a diameter of 22 mm.

4. The support structure for the slag collection pit of the water diversion tunnel as described in claim 1, characterized in that, The thickness of the shotcrete layer is 12 cm.

5. The support structure for the slag collection pit of the water diversion tunnel as described in claim 1, characterized in that, The number of connecting rods located on the same central connecting mechanism is 4 to 6.

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