CN113700513B - Combined tunnel anchorage structure - Google Patents
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- CN113700513B CN113700513B CN202110886409.8A CN202110886409A CN113700513B CN 113700513 B CN113700513 B CN 113700513B CN 202110886409 A CN202110886409 A CN 202110886409A CN 113700513 B CN113700513 B CN 113700513B
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- 239000011435 rock Substances 0.000 claims abstract description 47
- 239000002131 composite material Substances 0.000 claims abstract description 17
- 238000013461 design Methods 0.000 claims abstract description 15
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 13
- 239000010959 steel Substances 0.000 claims abstract description 13
- 230000005484 gravity Effects 0.000 claims description 46
- 238000010008 shearing Methods 0.000 claims description 19
- 238000009412 basement excavation Methods 0.000 claims description 7
- 239000004567 concrete Substances 0.000 claims description 4
- 238000004873 anchoring Methods 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 150000001875 compounds Chemical class 0.000 claims 1
- 238000010276 construction Methods 0.000 abstract description 11
- 239000002689 soil Substances 0.000 abstract description 3
- 239000000725 suspension Substances 0.000 description 10
- 238000004364 calculation method Methods 0.000 description 9
- 230000001066 destructive effect Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 230000006378 damage Effects 0.000 description 4
- 230000003068 static effect Effects 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000009933 burial Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/008—Anchoring or tensioning means
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/23—Dune restoration or creation; Cliff stabilisation
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- Mining & Mineral Resources (AREA)
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- General Life Sciences & Earth Sciences (AREA)
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- Geology (AREA)
- Piles And Underground Anchors (AREA)
Abstract
The invention discloses a composite tunnel anchor structure which comprises a main cable access hole, a scattered cable chamber and a wedge-shaped chamber, wherein a scattered cable saddle is arranged in the main cable access hole, one end of the scattered cable chamber, which is close to the main cable access hole, is provided with a guide part, the interface of the scattered cable chamber and the wedge-shaped chamber is provided with a steering part, the base surface of the wedge-shaped chamber is provided with an anchor, the scattered cable chamber is internally provided with a front anchor block, the wedge-shaped chamber is internally provided with a rear anchor block, the central axis of the scattered cable chamber coincides with the central axis of the main cable access hole, the included angle between the central axis of the wedge-shaped chamber and the horizontal plane is larger than the incident angle of the main cable, the main cable is dispersed into steel strands from the main cable access hole through the scattered cable saddle, all the steel strands are averagely dispersed into the section of the scattered cable chamber through the guide part and pass through the front anchor block, are averagely dispersed into the section of the wedge-shaped chamber through the steering part, and finally are respectively fixed on the base surface of the wedge-shaped chamber through the anchor block. The invention effectively overcomes the problems of great increase of anchorage design and construction difficulty caused by insufficient surrounding rock and soil strength, and greatly reduces construction cost.
Description
Technical Field
The invention belongs to the technical field of geotechnical engineering, and particularly relates to a composite tunnel anchorage structure which is suitable for various surrounding rock conditions which are extremely susceptible to engineering disturbance and do not meet the bearing design requirement, such as soft rock, loose accumulation body side slopes and the like, and is designed by considering the initial state of the geotechnical and the degree of decline of physical mechanical parameters after deformation and softening, so that the stability of the side slopes before and after bearing the tunnel anchors is evaluated, and the engineering quantity and the engineering cost can be greatly reduced by adopting the composite tunnel anchorage.
Background
Two thirds of China's territories are mountain areas. Because mountain areas have complex geological structures and changeable lithology, the bridge-tunnel proportion of most highways/railways is high, especially 70% -80% in western mountain areas, and bridge construction becomes a serious importance of traffic construction. Suspension bridges are often the first choice for the mountain bridge type because of their excellent crossing ability. The suspension bridge mainly comprises four structures of an anchorage, a stiffening girder, a main cable and a bridge tower, wherein the anchorage is a key for bearing the main cable force of the suspension bridge. Anchorage is generally divided into gravity type (gravity anchor for short) and tunnel type (tunnel anchor for short), and the mechanical model and possible destruction modes are shown in FIG. 1.
The principle of the gravity anchor is that the horizontal component of the main cable tension is balanced by utilizing the base friction force between the basal surface and the ground, so that the gravity anchor body is huge, the construction is generally carried out by adopting modes of slope releasing, vertical enclosing, open caisson and the like on the land, a large construction site is needed, when the mountain area is located at a bridge site, the ground gradient is steep, the mountain is required to be excavated on a large scale, and the high slope protection is arranged, so that the engineering quantity and the engineering difficulty are great, and the ecological environment is destroyed.
The tunnel anchor can be well combined with engineering geological conditions of an anchor site area, the wedge-shaped anchor is utilized to drive the surrounding rock mass to bear together, the engineering scale of the tunnel anchor is generally far smaller than that of a gravity anchor with the same bearing capacity, and the tunnel anchor is in an anchor structure form which is small in size, free from large-scale excavation, investment-saving and small in influence on surrounding environment. However, the existing tunnel anchors are generally only suitable for being arranged in hard rock bodies with good surrounding rock conditions, the rock bodies where the tunnel anchors are positioned are good in integrity, and huge pulling resistance provided by the clamping effect of the surrounding rock can be fully utilized. And when the development of the rock mass joint structure belongs to broken rock and even clastic rock, surrounding rock is difficult to provide an effective clamping effect for anchorage. If the surrounding rock is worse, even if tunnel anchors are adopted, the design length of the tunnel anchors is greatly increased, and the world-longest tunnel anchors with the length of 159 meters of a certain suspension bridge are taken as an example. Because the construction difficulty of the ultra-long variable cross section anchor room underground excavation is extremely high, the construction safety is difficult to ensure, and the construction efficiency is extremely low, the tunnel anchor is not suitable for the situation.
Aiming at the defects in the prior two anchorage technologies, the patent proposes to construct a novel suspension bridge anchorage, namely a gravity type tunnel anchor, and a mechanical model of the novel suspension bridge anchorage is shown in the following figure 2. The gravity tunnel anchor is designed into two sections of anchors, wherein the upper anchor is a loose cable section, and the lower anchor is a wedge section. The scattered cable section is used for replacing the scattered cable saddle function of the original tunnel anchor, and the main cable steel cable is evenly dispersed to the section of the anchorage; the central axis of the wedge-shaped section is intersected with the horizontal line in a large angle, the gravity can resist the vertical component of the main cable force part, the wedge-shaped appearance can form the clamping effect on surrounding rock to resist the residual vertical component of the main cable force, the horizontal component of the main cable force is resisted by the horizontal shearing-resistant bearing capacity of the surrounding rock at the bottom of the anchorage, and the anti-skid design can be performed by referring to the base friction-slip damage mode of the gravity anchor; furthermore, if the damage mode that the anchorage is pulled out along the main cable force direction is considered, the anchorage burial depth can be adjusted until the anti-pulling design requirement is met. The novel anchorage combines the advantages of the gravity anchor and the tunnel anchor, and is suitable for steep hillside fields and broken rock mass sections.
Referring to the related research results of many scholars on the failure mode of the tunnel anchor, it can be known that the potential fracture surface of the tunnel anchor is the direction represented by the dashed line ① in fig. 1 when the tunnel anchor is loaded to the limit. Based on the above-mentioned basic mechanical analysis of the gravity type tunnel anchor, when two possible failure modes of integral overturning and horizontal sliding of the tunnel anchor can be predicted, a fracture surface represented by a broken line ② in fig. 2 may be generated in the surrounding rock body.
Through Chinese patent network and related paper website search, no patent for bearing a suspension bridge main cable by adopting a composite tunnel anchor exists at present. For the worse surrounding rock conditions of crushing and strong weathervaning, gravity anchors are usually adopted, or ultra-long tunnel anchors are adopted for design, and the requirement of main cable bearing design cannot be met due to the mechanical defects of the anchors, so that engineering design and construction difficulty are increased, engineering quantity is greatly increased, and the risk of side slope instability is caused. Therefore, it is particularly urgent to design a new tunnel anchor that is economical, reliable and safe.
Disclosure of Invention
Aiming at the current defect situations in the application of the current gravity anchor and tunnel anchor engineering, the composite tunnel anchor structure can effectively solve the problems that the broken or broken soft side slope is not easy to bear a main cable and the side slope is easy to unstably bear, well improves the current situations that the current anchor design method is single and engineering measures are conservative, practically improves the engineering structure design level in engineering practice, and can greatly reduce engineering cost.
The utility model provides a combined type tunnel anchorage structure, locate in the stratum of side slope sliding surface, including the main cable access hole parallel with main cable incident direction, insert the hole through the main cable and excavate scattered cable room, wedge room in proper order, scattered cable room's average cross-section is A and scattered cable room's lower extreme to length of upper end be a, wedge room's basement area is B and highly is B, install scattered cable saddle in the main cable access hole, scattered cable room is close to main cable access hole's one end is equipped with the guide, scattered cable room and wedge room's interface is equipped with the steering gear, wedge room's basal plane is equipped with the ground tackle, scattered cable room is equipped with preceding anchor block in the wedge room, scattered cable room is equipped with the back anchor block in the wedge room, scattered cable room is overlapped with main cable access hole's central axis direction, scattered cable room's central axis is close to side slope sliding surface and horizontal angle beta is greater than main cable's incident angle delta, scattered cable is scattered into the steel strand wires that the same with main cable quantity and arranging in the interval from main cable access hole through scattered cable saddle, all steel strand wires are scattered cable are evenly to scattered cable room's cross-section and pass through the anchor block to scatter cable room before and pass through anchor block to turn to the wedge, respectively after the averagely pass through the wedge-shaped wire after the wedge is fixed cross-section respectively after the anchor is turned to the wedge is passed through the ground to the wedge respectively;
The anchorage comprises a shearing resistant structure anchored into the basal surface of the wedge-shaped chamber and an anchoring connector connected with each steel strand, wherein the shearing resistant structure comprises a pulling-resistant pile and a shearing-resistant pile/shearing-resistant wall anchored into the lower part of the basal surface of the wedge-shaped chamber, and the shearing-resistant pile/shearing-resistant wall is arranged at the bottom of the wedge-shaped chamber or at one side of the sliding surface of the side slope at the bottom of the wedge-shaped chamber;
When the main cable is designed to bear the force P, n anti-pulling piles with the anti-pulling force of F k are arranged, and the area of the shearing pile/shearing wall with the shearing strength of J is s, the cable scattering chamber and the wedge chamber design parameters meet the following conditions:
nFk+Aaρ+Bbρ≥Psinδ；
sJ≥Pcosδ；
ρ is the density of the concrete poured in the loose cable chamber and the wedge chamber.
Further, the sections of the front anchor block and the rear anchor block are round, oval, rectangular, polygonal or a combination of the shapes, the section area of the front anchor block and the rear anchor block is gradually increased from the front anchor surface to the rear anchor surface, the main cable access hole, the cable scattering chamber and the wedge-shaped chamber all comprise supporting layers attached to the surfaces of the front anchor block and the rear anchor block, and the front anchor block, the rear anchor block and the surrounding supporting layers form a tunnel/gravity anchor wrapped in a rock stratum under the action of a main cable.
Preferably, the included angle is in the range 179 ° -10 °.
Preferably, the guide comprises a honeycomb structure made up of a plurality of sleeves, or a rigid pad of densely packed holes, and the steering comprises a rigid pad of densely packed holes.
Further, the anchor includes a shear structure anchored into the wedge chamber footprint and an anchor connector connected to each steel strand.
Further, the shear structure comprises a shear pile anchored below the base surface of the wedge-shaped chamber, and a shear pile or a shear wall arranged at the bottom of the wedge-shaped chamber or at one side of the bottom of the wedge-shaped chamber close to the sliding surface of the slope.
Further, the shearing resistant structure also comprises a sawtooth-shaped rigid bottom plate, and tooth grooves of the sawtooth-shaped rigid bottom plate are parallel to the side slope sliding surface.
The anchorage integrates various technical means such as a gravity anchor, a tunnel anchor and the like, considers the change of physical and mechanical parameters of rock and soil before and after engineering excavation, and is a novel composite tunnel anchor structure for anchoring a main cable of a suspension bridge and a construction method thereof. According to the method, basic geometric forms, initial states, physical and mechanical parameters of rock and soil after deformation softening and the like of the side slope are obtained through field investigation and indoor experiments, and the novel anchorage structure integrating the advantages of the gravity anchor and the tunnel anchor is adopted to bear the main cable force of the suspension bridge.
The invention establishes a novel anchorage structure bearing suspension bridge main cable force with simple structure and clear mechanics principle, and has the beneficial effects compared with the prior art that: the tunnel/gravity anchor comprises a tunnel anchor of a front anchor block and a gravity anchor of a rear anchor block, not only utilizes the base friction force of the ground surface of the gravity anchor and the ground to balance the horizontal component of the main cable tension, but also utilizes the huge pulling resistance provided by the clamping effect of surrounding rocks around the tunnel anchor, and based on mechanical analysis, the potential fracture surface which can generate horizontal sliding and integral overturning when the tunnel/gravity anchor is carried to the limit can be predicted to be parallel to the base surface of the rear anchor block and symmetrical to the central axis of the base surface of the rear anchor block relative to the main cable access hole.
To horizontally slide the tunnel/gravity anchor, three components are overcome: 1. the anchorage and the horizontal component of static friction force generated by the total weight of the rock mass area between the side of the anchorage close to the side slope and the fracture surface; 2. shearing force of the shear resistant structure at the bottom of the anchorage; 3. the horizontal component of the friction force between the surrounding rock and the surface of the front anchor block, so that the horizontal destructive force required by the horizontal sliding of the tunnel/gravity anchor is larger than the destructive force required in the scheme of arranging the gravity anchor near the side slope (without the friction force between the surrounding rock and the anchor).
To topple the tunnel/gravity anchor as a whole, three components must be overcome: 1. the anchorage and the horizontal component of static friction force generated by the total weight of the rock mass area between one side of the anchorage close to the side slope and the fracture surface, and the total weight of the rock mass area on the upper surface of the front anchor block; 2. pile pulling force of the shear structure at the bottom of the anchorage; 3. the extrusion force of the surrounding rock and the upper surface of the front anchor block, so that the destructive force required by the integral overturning of the tunnel/gravity anchor is larger than the destructive force required in the scheme of arranging the gravity anchor near the side slope (the total gravity of the rock above the anchor and the gravity of the anchor).
Therefore, the total volume of the anchorage is smaller than that of a pure gravity anchorage, the excavation amount of an anchor chamber is reduced, and the problem of structural instability caused by the dead weight of the gravity anchorage to scraps or broken soft slopes is avoided.
The pure tunnel anchor can achieve the same anti-overturning and anti-sliding capacity only by enlarging the total volume of surrounding rocks in the area of the covered fracture surface in the broken line ① to be equal to the total volume of surrounding rocks in the area between the fracture surfaces of the overturning fracture and the sliding fracture in the invention, so that the length of the tunnel to be excavated is extremely long, and the engineering quantity is larger than that of the invention.
Drawings
FIG. 1 is a schematic diagram of a failure mode of a purely gravitational anchor;
FIG. 2 is a schematic diagram of a failure mode of a pure tunnel anchor;
FIG. 3 is a layout of a composite tunnel anchor structure in example 1;
FIG. 4 is a graph showing angles between the central axes of the front anchor block and the rear anchor block and the horizontal plane of the composite tunnel anchor structure in example 1;
FIG. 5 is a schematic diagram of the failure mode of the composite tunnel anchor structure of example 1;
FIG. 6- (a) (b) is a graph of conventional tunnel anchor calculation results;
fig. 7- (c) (d) is a graph of the calculation results of the composite tunnel anchor structure.
The specific embodiment is as follows:
The following examples are set forth in order to provide those of ordinary skill with a more thorough understanding and appreciation of the present invention and are not to be construed in any way as limiting the scope of the claimed invention.
Example 1:
As shown in fig. 3, a composite tunnel anchorage structure is arranged in a rock stratum 14 of a slope sliding surface 1, and comprises a main cable access hole 2 parallel to the incidence direction of a main cable 11, a loose cable chamber 3 and a wedge-shaped chamber 4 which are formed by sequentially excavating the main cable access hole 2, wherein the average sectional area of the loose cable chamber 3 is a=30m 2, the length from the lower end to the upper end of the loose cable chamber 3 is a=10m, the base area of the wedge-shaped chamber 4 is b=50m 2, the height of the wedge-shaped chamber is b=20m, a chamber surrounding rock supporting layer 13 is manufactured by adopting modes such as anchor spraying after the excavation of the main cable access hole 2, the loose cable saddle 5 is arranged in the main cable access hole 2, a guide piece 6 is arranged at one end of the loose cable chamber 3 close to the main cable access hole 2, the guide piece 6 comprises a honeycomb structure formed by a plurality of sleeves or a rigid pad plate densely distributed with holes, the interface between the loose cable chamber 3 and the wedge-shaped chamber 4 is provided with a steering piece 7, the steering piece 7 comprises a rigid backing plate with densely distributed holes, the base surface of the wedge-shaped chamber 4 is provided with an anchorage device 8, the loose cable chamber 3 is internally provided with a front anchorage block 9, the wedge-shaped chamber 4 is internally provided with a rear anchorage block 10, the loose cable chamber 3 coincides with the central axis direction of the main cable access hole 2, the included angle between the central axis of the main cable access hole 2 and the horizontal plane is delta, the included angle between the central axis of the wedge-shaped chamber 4, which is close to one side of the slope sliding surface 1, and the horizontal plane is beta, beta=60 DEG is larger than the incident angle delta=30 DEG of the main cable 11, the cross sections of the front anchorage block 9 and the rear anchorage block 10 are round, elliptic, rectangular, polygonal, or a combination of the shapes, the cross section areas of the front anchorage block 9 and the rear anchorage surface are gradually increased, the support layers 13 of the main cable access hole 2, the loose cable chamber 3 and the wedge-shaped chamber 4 are attached to the surfaces of the front anchorage block 9 and the rear anchorage block 10, the front anchor block 9, the rear anchor block 10 and the surrounding supporting layer 13 form a tunnel/gravity anchor wrapped in a rock stratum 14 under the action of the tensile stress of the main cable 11, the main cable 11 is dispersed into steel strands 12 which are arranged side by side at intervals with the same number as the main cable 11 from the main cable access hole 2 through the cable dispersing saddle 5, all the steel strands 12 are evenly dispersed into the section of the cable dispersing chamber 3 through the guide piece 6 and pass through the front anchor block 9, are turned through the turning piece 7 and evenly dispersed into the section of the wedge-shaped chamber 4, and finally pass through the rear anchor block 10 and are respectively fixed on the basal surface of the wedge-shaped chamber 4 through the anchor 8.
As shown in fig. 4, the included angle β ranges from 179 ° to 30 °, in this embodiment β=60°, and the front anchor block 9 and the rear anchor block 10 are both reinforced concrete structures. The anchorage means 8 comprises a shear structure anchored into the floor of the wedge-shaped chamber 4 and an anchor connector connected to each steel strand 12, in particular as an option the shear structure comprises a shear pile 15 anchored into the underside of the wedge-shaped chamber 4 and a shear pile or wall 16, the shear pile or wall 16 being arranged at the bottom of the wedge-shaped chamber 4 or at the side of the wedge-shaped chamber 4 against the slope sliding surface 1.
When the main cable 11 is designed to bear a force p=10000 tons, and n anti-pulling piles 15 with a pulling resistance of F k are arranged, and the area of the shear piles/shear walls 16 with a shear strength of 2Mpa is s, the design parameters of the cable scattering chamber 3 and the wedge chamber 4 meet the following conditions:
nFk+Aaρ+Bbρ≥Psinδ；
sJ≥Pcosδ；
ρ is the density of the concrete poured in the loose cable chamber 3 and the wedge-shaped chamber 4, ρ=2.5 tons/m 3;
From the calculation n= (psinδ -aaρ -Bb ρ)/(F k = (5000-750-2500) +.150=11.6+.12;
S＝Pcosδ÷J＝8660÷2＝43.3m2；
from the above, when the casting volume of the cable dispersing chamber 3 and the wedge-shaped chamber 4 reaches 1300m 3, the requirement that the stress of the designed main cable reaches 10000 tons can be met by arranging the anti-pulling piles and the shear walls.
Alternatively, the shear structure further comprises a serrated rigid base plate with tooth slots parallel to the slope sliding surface 1.
(1) If the front anchor block 9 and the rear anchor block 10 are both plain concrete and no shear-resistant structure is arranged, the sections of the composite tunnel anchor structure and the pure tunnel anchor model are both semicircular and rectangular, the areas are equal, other calculation parameters and calculation results are shown in table 1 under the condition that main design parameters such as surrounding rock category, main cable force and burial depth are the same, the cloud chart of the calculation results is shown in fig. 6, and the damage schematic chart is shown in fig. 5.
Table 1: numerical simulation calculation parameters and calculation results (size: m; stress: MPa) of composite tunnel anchor structure and pure tunnel anchor
As shown in fig. 5, the tunnel/gravity anchor of the present invention includes a tunnel anchor of a front anchor block and a gravity anchor of a rear anchor block, which use the base friction force between the ground and the ground to balance the horizontal component of the main cable tension, and use the huge pulling resistance provided by the "clamping effect" of surrounding rocks around the tunnel anchor, based on mechanical analysis, it can be predicted that the potential fracture surface ② that slides horizontally when the tunnel/gravity anchor is loaded to the limit is parallel to the base surface of the rear anchor block, and the potential fracture surface ② that is integrally tipped when the tunnel/gravity anchor is loaded to the limit is symmetrical to the base surface of the rear anchor block with respect to the central axis of the main cable access hole.
To horizontally slide the tunnel/gravity anchor, three components are overcome: 1. the anchorage and the horizontal component of static friction force generated by the total weight of the rock mass area between the side of the anchorage close to the side slope and the fracture surface ②; 2. shearing force of the shear resistant structure at the bottom of the anchorage; 3. the horizontal component of the friction force between the surrounding rock and the surface of the front anchor block, so that the horizontal destructive force required by the horizontal sliding of the tunnel/gravity anchor is larger than the destructive force required in the scheme of arranging the gravity anchor near the side slope (without the friction force between the surrounding rock and the anchor).
To topple the tunnel/gravity anchor as a whole, three components must be overcome: 1. the anchorage and the horizontal component of static friction force generated by the total weight of the rock mass area between the side of the anchorage close to the side slope and the fracture surface ②, and the total weight of the rock mass area on the upper surface of the front anchor block; 2. pile pulling force of the shear structure at the bottom of the anchorage; 3. the extrusion force of the surrounding rock and the upper surface of the front anchor block, so that the destructive force required by the integral overturning of the tunnel/gravity anchor is larger than the destructive force required in the scheme of arranging the gravity anchor near the side slope (the total gravity of the rock above the anchor and the gravity of the anchor).
Therefore, the shear-resistant structure is arranged in the invention, so that the total volume of the anchorage is far smaller than that of a pure gravity anchorage, the excavation amount of an anchor chamber is reduced, the problem of structural instability caused by the dead weight of the gravity anchorage to scraps or broken weak slopes is avoided, and the technical effect is far beyond expectations and is remarkable.
The pure tunnel anchor is required to expand the total volume of surrounding rock in the area of the covered fracture surface in the broken line ① to be equal to the total volume of surrounding rock in the area between the fracture surfaces ② of the overturning fracture and the sliding fracture in the invention so as to achieve the same anti-overturning and anti-sliding capacity, so that the length of the tunnel to be excavated is extremely long, and the engineering quantity is larger than that of the invention. As the results of the calculation in table 1, the length and the volume of the composite tunnel anchor structure of the invention are smaller than those of the pure tunnel anchor model.
Claims (4)
1. The utility model provides a compound tunnel anchorage structure, locate in rock stratum (14) of side slope sliding surface (1), its characterized in that, including main cable access hole (2) parallel with main cable (11) incident direction, through main cable access hole (2) excavation in proper order formation loose cable room (3), wedge room (4), the average sectional area of loose cable room (3) is A and the length of loose cable room (3) lower extreme to upper end is a, the area of the basement of wedge room (4) is B and highly is B, install loose cable saddle (5) in main cable access hole (2), the one end that loose cable room (3) is close to main cable access hole (2) is equipped with direction (6), the interface of loose cable room (3) and wedge room (4) is equipped with steering gear (7), the basal plane of wedge room (4) is equipped with ground tackle (8), be equipped with preceding anchor piece (9) in the loose cable room (3), be equipped with back anchor piece (10) in the wedge room (4), loose cable room (3) and the central axis direction of main cable access hole (2) are close to main cable (2) the inclined angle of incidence of angle that is big side (11) is close to main cable (1), the main cables (11) are scattered into steel strands (12) which are arranged side by side at intervals and have the same number as the main cables (11) from the main cable access holes (2) through the cable scattering saddles (5), all the steel strands (12) are evenly scattered into the section of the cable scattering chamber (3) through the guide piece (6) and pass through the front anchor block (9), are turned through the turning piece (7) and evenly scattered into the section of the wedge-shaped chamber (4), and finally pass through the rear anchor block (10) and are respectively fixed on the basal surface of the wedge-shaped chamber (4) through the anchors (8);
the anchorage device (8) comprises a shearing resistant structure anchored into the basal surface of the wedge-shaped chamber (4) and an anchoring connector connected with each steel strand (12), wherein the shearing resistant structure comprises a pulling pile (15) and a shearing pile/shearing wall (16) anchored into the lower part of the basal surface of the wedge-shaped chamber (4), and the shearing pile/shearing wall (16) is arranged at the bottom of the wedge-shaped chamber (4) or at one side of the bottom of the wedge-shaped chamber (4) close to the side slope sliding surface (1);
When the main cable (11) is designed to bear a force P, and n anti-pulling piles (15) with the pulling resistance Fk are arranged, and the area of the arranged shear piles/shear walls (16) with the shear strength J is s, the design parameters of the cable scattering chamber (3) and the wedge-shaped chamber (4) meet the following conditions:
nFk+Aaρ+Bbρ≥Psinδ；
sJ≥Pcosδ；
ρ is the density of the concrete poured in the loose cable chamber (3) and the wedge-shaped chamber (4);
the included angle beta is 60 degrees.
2. The composite tunnel anchorage structure according to claim 1, wherein the cross sections of the front anchor block (9) and the rear anchor block (10) are round, oval, rectangular, polygonal, or a combination of the above shapes, the cross sectional areas of the front anchor block and the rear anchor block gradually increase from the front anchor surface to the rear anchor surface, the main cable access hole (2), the cable scattering chamber (3) and the wedge-shaped chamber (4) comprise supporting layers (13) attached to the surfaces of the front anchor block (9) and the rear anchor block (10), and the front anchor block (9) and the rear anchor block (10) and the surrounding supporting layers (13) form a tunnel/gravity anchor wrapped in the rock layer (14) under the action of the main cable (11).
3. A composite tunnel anchorage according to claim 1, wherein the guide (6) comprises a honeycomb structure of a plurality of sleeves, or a rigid pad of densely packed holes, and the deflector (7) comprises a rigid pad of densely packed holes.
4. The composite tunnel anchorage structure according to claim 1, wherein the shear resistant structure further comprises a serrated rigid base plate having tooth slots parallel to the side slope sliding surface (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110886409.8A CN113700513B (en) | 2021-08-03 | 2021-08-03 | Combined tunnel anchorage structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110886409.8A CN113700513B (en) | 2021-08-03 | 2021-08-03 | Combined tunnel anchorage structure |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2656883A1 (en) * | 1990-01-11 | 1991-07-12 | Freyssinet Int Stup | IMPROVEMENTS ON BRIDGE BRIDGES AND MORE ESPECIALLY THEIR BRIDGES, PYLONES AND APRON. |
| CN108867378A (en) * | 2018-09-17 | 2018-11-23 | 四川省铁路产业投资集团有限责任公司 | A kind of Techniques of Tunnel-Type Anchorage for Suspension Bridge and construction method |
| CN110629671A (en) * | 2019-10-31 | 2019-12-31 | 中铁大桥勘测设计院集团有限公司 | Suspension bridge anchorage and construction method thereof |
| CN211395370U (en) * | 2019-10-31 | 2020-09-01 | 中铁大桥勘测设计院集团有限公司 | Suspension bridge anchorage |
| CN111663444A (en) * | 2020-06-28 | 2020-09-15 | 长江水利委员会长江科学院 | Suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure and construction method |
| CN113089482A (en) * | 2021-05-17 | 2021-07-09 | 湖南科技大学 | Double-hole single-anchor system and construction method thereof |
-
2021
- 2021-08-03 CN CN202110886409.8A patent/CN113700513B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2656883A1 (en) * | 1990-01-11 | 1991-07-12 | Freyssinet Int Stup | IMPROVEMENTS ON BRIDGE BRIDGES AND MORE ESPECIALLY THEIR BRIDGES, PYLONES AND APRON. |
| CN108867378A (en) * | 2018-09-17 | 2018-11-23 | 四川省铁路产业投资集团有限责任公司 | A kind of Techniques of Tunnel-Type Anchorage for Suspension Bridge and construction method |
| CN110629671A (en) * | 2019-10-31 | 2019-12-31 | 中铁大桥勘测设计院集团有限公司 | Suspension bridge anchorage and construction method thereof |
| CN211395370U (en) * | 2019-10-31 | 2020-09-01 | 中铁大桥勘测设计院集团有限公司 | Suspension bridge anchorage |
| CN111663444A (en) * | 2020-06-28 | 2020-09-15 | 长江水利委员会长江科学院 | Suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure and construction method |
| CN113089482A (en) * | 2021-05-17 | 2021-07-09 | 湖南科技大学 | Double-hole single-anchor system and construction method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 抗拔桩在人防地下室工程中的应用;杨瀛;;宁夏工程技术(第01期);81~83 * |
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