CN111663444A - Suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure and construction method - Google Patents

Abstract

The invention provides a composite anchor structure and a construction method of a suspension bridge tunnel anchor and a rock mass anchor. The composite anchorage structure includes a main cable access hole arranged in the bridge position area of the suspension bridge, a scattered cable saddle room, a front anchor room and a rear anchor room which are sequentially constructed through the main cable access hole. A front anchor, an anchor plug, a rear anchor and a plurality of anchor cables are arranged between the anchor chambers. The front anchor is placed on the front anchor surface of the anchor plug, and its area is larger than the front anchor surface of the anchor plug. It is placed on the rear anchor surface of the anchor plug body, and its area is larger than the rear anchor surface of the anchor plug body. Multiple anchor cables pass through the anchor plug body and the rock mass around the anchor plug body from the front anchor body and then are fixed at the rear anchorage through anchors. The main cable of the suspension bridge is pulled from the main cable access hole into the scattered cable saddle room, and then dispersed through the scattered cable saddle and then connected with the corresponding anchor cable. The invention increases the bearing range of the rock mass, improves the bearing capacity of the anchor, can reduce the size of the anchor hole, and can be applied to the rock mass with poor engineering quality.

Description

A suspension bridge tunnel anchor and rock mass anchor composite anchorage structure and construction method

technical field

The invention belongs to the technical field of bridge engineering and relates to an anchorage structure of a suspension bridge, in particular to a composite anchorage structure of a suspension bridge tunnel anchor and a rock mass anchor and a construction method.

Background technique

At present, the anchor structures of suspension bridges mainly include gravity anchors, tunnel anchors, gravity anchors (tunnel anchors) + composite anchors of anchor cables, rock mass anchors, rock mass and reinforced concrete slab anchors and Concrete beam rock anchors, etc. Gravity anchors are used in weak rock foundations, relying on the friction between their own weight and the foundation to resist the pulling force of the main cable. The amount of earth and stone excavation and concrete construction is large, and the impact on the ecological environment is also large. Tunnel anchors are usually built in relatively hard or complete rock mass, and most of the tension in the main cable is transmitted to the surrounding rock through the anchor body. Small, but large-tonnage bridges still require large tunnel anchorages, and the amount of cavern excavation and concrete pouring is also large. The pull-out test of the similar scaled model of the tunnel anchorage shows that most of the main cable tension is transmitted to the surrounding rock only by shear friction through the middle and rear side walls of the anchor body, accounting for about 70% of the main cable tension. , lengthening the anchor body can not greatly improve the bearing capacity of the anchor body, and the surrounding rock itself is not fully supported. The composite anchorage of tunnel anchorage + anchor cable is to transfer part of the load to the rock mass by adding anchor cable at the back of the gravity anchorage or tunnel anchorage. The output of the anchor cable and the anchor body is not easy to coordinate. The durability of the cable is difficult to guarantee, and the force is not uniform.

In order to solve the problems that the output of the anchor cable and the anchor body is not easy to coordinate, and the amount of earth, stone and concrete is large, the patent of the authorized announcement number CN105648921 B discloses a construction method of a suspension bridge rock mass and a reinforced concrete slab composite anchor. A composite anchorage of rock mass and reinforced concrete slab is specifically disclosed in the invention. Through the anchor cable anchored on the reinforced concrete slab, the tension of the main cable of the suspension bridge is directly transmitted to the rock mass, and its performance is safe and reliable, cost saving, and conducive to environmental protection. . Rock mass anchors, rock mass and reinforced concrete slab composite anchors, and concrete beam rock anchors require a large number of anchor cable perforations, which weakens the integrity of the rock mass, and is only suitable for the I-III rock mass with higher engineering quality. And less application, lack of experience.

With the development of the national economy and the needs of traffic engineering construction, double-deck, dual-use, long-span and large-tonnage suspension bridges will emerge. Tonnage level, which puts forward higher requirements for the bearing capacity of the anchor, and the use of the above anchor will inevitably increase the volume of the anchor or increase the number of anchor cables. However, the suspension bridge is limited by the line and topography, and the tunnel anchorage often needs to be built in the IV~V grade rock mass with lower engineering quality. The height of the anchor hole is more than 24m. At this time, it is extremely difficult to form a hole, and there is a great potential safety hazard. The excavation and concrete volume increase greatly, the investment is huge, the construction period is long, and the risk is high.

SUMMARY OF THE INVENTION

According to the deficiencies of the prior art, the present invention provides a composite anchor structure of a suspension bridge tunnel anchor and a rock mass anchor and a construction method thereof. The composite anchor retains the bearing characteristics of the traditional tunnel anchor body and effectively utilizes the periphery of the anchor plug body. Rock mass, reduce the cross-sectional size of the anchor plug chamber, reduce the amount of excavation and concrete, and correspondingly increase the bearing capacity of the anchor and reduce the project cost.

In order to achieve the above technical purpose, the technical solution provided by the present invention is a composite anchorage structure of a suspension bridge tunnel anchor and a rock mass anchor. The composite anchorage structure includes a main cable access hole arranged in the bridge position area of the suspension bridge. The cable saddle room, the front anchor room and the rear anchor room are formed by the construction of the main cable access hole in sequence. The front anchor body, the anchor plug body, the rear anchor body and a plurality of anchor cables are arranged between the front anchor room and the rear anchor room. , the front anchor is placed on the front anchor surface of the anchor plug body, and its area is larger than the front anchor surface of the anchor plug body, and the rear anchor body is placed on the rear anchor surface of the anchor plug body, and its area is larger than the rear anchor surface of the anchor plug body. The anchor cable passes through the anchor plug body and the rock mass around the anchor plug body from the front anchor body and is fixed on the rear anchor body through the anchor; The saddles are divided into main cable strands with the same number as the anchor cables, and each main cable strand is connected to the corresponding anchor cable through the anchor connector.

A further technical scheme of the present invention: the cross-section of the anchor plug body is in the shape of a city gate or a horseshoe or a circle, and its cross-sectional area gradually increases from the front anchor to the rear anchor surface, forming a wedge-shaped body with a small front and a large rear; the anchor plug The body and the rear anchor body form the tunnel anchor, the front anchor body is separated from the anchor plug body, and forms a rock mass anchor wrapped outside the tunnel anchor with the rear anchor body and the rock mass around the anchor plug body under the action of the anchor cable.

The preferred technical scheme of the present invention: the cross-sections of the front anchor and the rear anchor are the same as the cross-sectional shape of the anchor plug body, the anchor plug body and the rear anchor body are an integrated reinforced concrete structure, and the front anchor body is placed in the anchor Around the front side of the front anchor of the plug body, the rear anchor body and the anchor plug body are connected by an arc-shaped or hemispherical surface body.

The preferred technical scheme of the present invention is that the front anchor chamber is backfilled with concrete in the area where the front anchor body is larger than the front anchor surface of the anchor plug body corresponding to the front anchor chamber; The rock mass between the outer edge of the front anchor and the rear anchor at the periphery of the plug body, and the rock mass between the periphery of the plug body, the connection line between the outer edge of the front anchor and the rear anchor to form a surrounding tunnel anchor. Rock mass anchor; the anchor cable pipe is pre-buried in the anchor plug body, the anchor cable hole is set in the front anchor body, the rock mass around the anchor plug body, the rear anchor body and the front anchor room reinforcement, and the anchor cable is installed in the anchor cable hole. The cable pipe, the anchor cable pipe in the rock body and the anchor cable pipe in the front anchor room reinforcement body are connected in the form of fillet or arc tangent in the front anchor room reinforcement. Multiple anchor cables are connected from the front anchor surface and the front anchor room. The anchor cable pipes of the reinforcement body respectively pass through the anchor plug body and the rock mass around the front reinforcement body and the anchor plug body, and then are fixed on the rear anchor body by means of anchors.

The preferred technical solution of the present invention is that the plurality of anchor cables pass through the anchor cable pipe and the anchor cable holes to the rear anchor room and are anchored on the rear anchor body with anchors, and the front ends of the anchor cables in the tunnel anchor are fixed in the tunnel with anchors. On the front anchor surface of the anchor, the anchor cable in the rock mass anchor is fixed on the front anchor room reinforcement, and each main cable strand is connected with the corresponding anchor through the anchor connector; the front anchor room reinforcement is on the main cable. A reinforced structure formed by backfilling reinforced concrete after the strand and the anchor cable are connected at the front end of the front anchor.

In the present invention, the resultant force line of the anchor plug body coincides with the resultant force line of the main cable, and the cross-sectional resultant force point of the front anchor body and the cross-section resultant force point of the rear anchor body are both on the main cable force line.

The invention provides a method for constructing a composite anchor structure of a suspension bridge tunnel anchor and a rock mass anchor, which is characterized in that the specific steps are as follows:

(1) Determine the position of the front anchor room according to the design drawings and construction stakeout, excavate the main cable access hole on one or both sides of the mountain slope of the suspension bridge, and excavate the scattered cable saddle room in the shape of a city gate hole by smooth blasting. Front anchor room, front anchor room, anchor room and rear anchor room; the size of the anchor room is constructed according to the size of the anchor plug body and the rear anchor, and the front anchor room starts to expand outward from the bottom of the cable saddle room To be consistent with the width of the front anchor chamber, the width of the rear anchor chamber and the anchor chamber corresponding to the part of the rear anchor are the same, and the section of the anchor chamber is in the shape of a city gate or horseshoe or circle;

(2) Start to carry out shotcrete and grouting reinforcement for the broken surrounding rock of the front anchor room, carry out initial shotcrete support for the front anchor room and anchor body room, grouting local small pipes, and erect steel arch support for the surrounding rock section. Protect the surrounding rock, the surrounding rock of the rear anchor room is reinforced by shotcrete and grouting, and the main cable access hole, the scattered cable saddle room, the front anchor room and the rear anchor room are lined with concrete;

(3) After the excavation of the anchor body room and the rear anchor room is completed and the bottom is cleared, the anchor cable pipe and steel bar are precisely positioned and installed in the anchor body room. Center; pre-embed the grouting pipe between the contact surface of the anchor plug body and the rock mass, install the back anchor surface formwork, pour the micro-expansion concrete layer by layer, vibrate and compact, and cure the concrete to form an integral body composed of the anchor plug body and the back anchor body type anchor structure;

(4) According to the design drawings and construction lofting, make and install steel bars in the front anchorage room, pre-embed steel pipes in the drilled parts, and then pour concrete. After the concrete strength reaches the design strength, drill from the embedded steel pipes to the rear anchor surface by a drilling rig. During the bolt hole, the rock mass with broken rock mass and poor integrity is grouted to strengthen the rock mass to improve the integrity and bearing capacity of the rock mass.

(5) Install the anchor cable in the anchor cable hole. The anchor cable in the rock mass is installed with the anchor cable tube outside the front anchor body to the front anchor room, and then the front anchor room corresponding to the front anchor body is larger than the front anchor surface of the anchor plug body with reinforced concrete. The area is backfilled to form the front anchor chamber reinforcement;

(6) Excavate the foundation of the scatter cable saddle in the scatter cable saddle room, pour the reinforced concrete base of the scatter cable saddle, install the scatter cable saddle after reaching the design strength, and then pull the main cable of the suspension bridge in, and disperse it into the anchor cable through the scatter cable saddle. For the main cable strands with the same number, use anchor connectors to connect the anchor cables to the main cable strands one by one in a one-to-one correspondence;

(7) After the concrete of the anchor plug body reaches the design strength, install the anchor on the surface of the rear anchor body, start from the central anchor cable, and tension the anchor cable layer by layer to the outer ring symmetrically, and use the anchor cable after the single anchor cable reaches its design load. The tool is anchored to the anchor plug body until all the anchor cables are tensioned and anchored. Finally, the anti-corrosion and lubricating oil body of the anchor cable is poured into the anchor cable pipe to complete the construction of the composite anchor structure.

The middle part of the composite anchor in the present invention is an inverted wedge-shaped anchor plug body with a small front and a large rear, and a cross-section of a city gate hole shape or a circle or a horseshoe shape. The rear end face of the anchor plug body is provided with a rear anchor body with an area larger than the rear end face, and the anchor cables are distributed in the anchor plug body and the rock body around the anchor plug body. The anchor body is integrally poured with reinforced concrete, and the enlarged part of the front anchor chamber beyond the front anchor surface of the anchor plug body is filled with reinforced concrete, and now the front anchor chamber reinforcement is formed. The rock mass between them forms a ring-shaped rock anchor body; the anchor structure in the present invention not only retains the bearing characteristics of the traditional tunnel anchor body, but also effectively utilizes the surrounding rock mass of the anchor plug body, reduces the cross-sectional size of the anchor hole, and reduces the size of the hole. The amount of excavation and concrete increases the bearing capacity of the anchorage accordingly. Under the same surrounding rock level and bearing capacity, the composite anchor is shorter than the traditional tunnel anchor, which can shorten the length of the cavern and reduce the section of the cavern, thereby reducing the amount of excavation and concrete, reducing the project cost and shortening the length of the tunnel. duration.

Description of drawings

Fig. 1 is the vertical sectional view of the anchorage structure in the present invention;

Fig. 2 is A-A sectional view in Fig. 1;

FIG. 3 is a sectional view taken along the line B-B in FIG. 1 .

In the figure: 1—main cable access hole, 2—scatter cable saddle room, 3—front anchor room, 4—front anchor body, 5—anchor plug body, 6—rear anchor body, 7—rear anchor room, 8— Main cable, 9—scatter cable saddle, 10—anchor cable, 11—main cable strand, 12—anchor connector, 13—rock mass, 14—anchorage, 15—anchor cable hole, 16—anchor cable pipe, 17— Front anchor chamber reinforcement.

Detailed ways

The specific embodiments of the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention.

1 to 3 are structural drawings of the composite anchorage of the suspension bridge tunnel anchor and rock mass anchor in the embodiment, which are drawn in a simplified manner, and are only used for clearly and concisely explaining the purpose of the embodiment of the present invention. The following technical solutions shown in the accompanying drawings are specific solutions of the embodiments of the present invention, and are not intended to limit the scope of the claimed invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on those shown in the accompanying drawings The orientation or positional relationship, or the orientation or positional relationship that the product of the invention is usually placed in use, or the orientation or positional relationship that is commonly understood by those skilled in the art, are only for the convenience of describing the present invention and simplifying the description, rather than indicating or It is implied that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the invention.

A composite anchorage structure of a suspension bridge tunnel anchor and a rock mass anchor provided in the embodiment, as shown in FIGS. 1 to 3 , the composite anchorage structure includes a main cable access hole 1 arranged in the bridge position area of the suspension bridge. , the cable saddle room 2, the front anchor room 3 and the rear anchor room 7 are sequentially constructed through the main cable access hole 1, and the front anchor body 4 and the anchor plug body are arranged between the front anchor room 3 and the rear anchor room 7. 5. The rear anchor body 6 and a plurality of anchor cables 10, the cross section of the anchor plug body 5 is in the shape of a city gate or a horseshoe or a circle, and its cross-sectional area gradually increases from the front anchor to the rear anchor surface, forming a small front and a large rear. Wedge-shaped body; the front anchor 4 is placed on the front anchor surface of the anchor plug body 5, and the area is larger than the front anchor surface of the anchor plug body 5, and the rear anchor body 6 is placed on the rear anchor surface of the anchor plug body 5, and the area is larger than the anchor plug The rear anchor surface of the body 5, the front anchor body 4 and the rear anchor body 6 have the same cross-section as the anchor plug body 5, and the contact surface between the rear anchor body 6 and the anchor plug body 5 is an arc or hemispherical surface body. The anchor plug body 5 and the rear anchor body 6 are integrated into a reinforced concrete structure to form a tunnel anchor. The front anchor body 4 is placed around the front side of the front anchor of the anchor plug body 5, and the front anchor body 4 in the front anchor chamber 3 is larger than The area of the front anchor surface of the anchor plug body 5 is backfilled with concrete to form the front anchor chamber reinforcement body 17; a plurality of anchor cables 10 respectively pass through the anchor plug body 5 and the front reinforcement body from the front anchor surface and the anchor cable pipes 16 of the front anchor chamber reinforcement body 17 4 and the rock mass 13 around the anchor plug body 5 are fixed on the rear anchor body 6 through the anchor 14, the front end of the anchor cable 10 in the tunnel anchor is fixed on the front anchor surface of the tunnel anchor with the anchor, the anchor in the rock anchor The cable 10 is fastened to the front anchor chamber reinforcement 17 . A plurality of anchor cables 10 are uniformly distributed in an annular shape in the rock mass 13 between the anchor plug body 5 and the outer edge connecting line of the front anchor body 4 and the rear anchor body 6 of the anchor plug body 5 , and are anchored with the outer periphery of the anchor plug body 5 . The rock mass 13 between the body 4 and the connecting line of the outer edge of the rear anchor body 6 forms a rock mass anchor; the anchor cables distributed in the anchor plug body 5 pass through the anchor cable pipes pre-installed in the anchor plug body 5, and are distributed in the anchor plug body 5. The anchor cables in the rock mass 13 on the periphery of the plug body 5 pass through the anchor cable pipes 16 in the anchor cable holes 15 drilled in the rock mass 13 in advance, and the front ends of the multiple anchor cables 10 are respectively fixed to the front anchor body through the anchors 14. 4, the anchor cable 10 in the rock mass 13 passes through the anchor cable tube 16 in the front anchor room reinforcement 17, the anchor cable tube 16 in the rock mass and the anchor cable tube 16 in the front anchor room reinforcement 17 are in front The anchor chamber reinforcements 17 are connected in a tangential manner with rounded corners or arcs. The main cable 8 of the suspension bridge is pulled from the main cable access hole 1 into the cable saddle room 2 and then dispersed into the same number of main cable strands 11 as the number of anchor cables 10 through the cable saddle 9, and each main cable strand 11 is connected by anchoring respectively. The device 12 is connected to the corresponding anchor cable 10 . The resultant force line of the anchor body 5 is coincident with the resultant force line of the main cable 8 .

The following is a detailed description of the construction method of the suspension bridge tunnel anchor and rock mass anchor composite anchorage structure in the present invention with reference to specific engineering examples, which include composite anchorages arranged on one side or both sides of the suspension bridge. The engineering geological conditions and physical and mechanical parameters of rock mass and concrete are as follows: schist, flaky structure, weak weathering to strong weathering, poor integrity of rock mass, relatively broken to broken, underdeveloped groundwater, unfavorable structural surface without control, rock mass engineering Most of the quality grades are grade IV, and local grades are V; the weight of rock mass γ=2.48g/cm ³ , the saturated uniaxial compressive strength of rock mass R _c =15～30MPa, and the average value of deformation modulus of rock mass E _o =7.5MPa , Poisson’s ratio μ=0.27, rock mass allowable bearing capacity [fa ]=0.75MPa; rock mass shear strength _f ’=0.85, c=0.55MPa, shear strength f=0.45; rock mass and concrete shear strength f'=0.75, c=0.50MPa, shear strength f=0.40. A single main cable bears 2.7×10 ⁵ kN, 109 main cable strands, 127 strands, galvanized high-strength steel wire: diameter Φ5mm, standard strength R _j ^b =1960MPa, PPWS method construction. Anchor body concrete: design code C40, micro-expansion; 109 anchor cable pipes, all of which are seamless steel pipes, the inner diameter of the pipe is φ12cm, and the material of the anchor cable pipe is Q345.

Anchor structure and size: the length of the main cable access section is 25m, the length of the cable saddle room is 5m, the shape of the gate hole: width × height = 7m × 8m; the anchor body: the shape of the gate hole, the length is 45m (including the length of the rear anchor 5m); front anchor room, city gate shape, length 10m; front anchor surface: city gate shape, width × height = 6m × 8m (corresponding tunnel anchor rear anchor surface: city gate shape, width × height = 7.8m × 9.8 m); rear anchor room: length 2.5m; rear anchor body: thickness 8.71m, curved surface body in the shape of city gate, width × height = 16.24m × 18.24m, radius of curved body 9.12m, and the side and curved surface of the anchor plug body The arc radius of the cut is 2.00m; the front anchor body: 3m thick, the shape of the city gate, width × height = 14m × 16m; the angle between the main cable and the anchor body and the horizontal plane is ∠37°.

The specific construction steps are as follows:

(1) Determine the position of the front anchor room according to the design drawings and construction stakeout, excavate the main cable access hole 1 on the side slope of the suspension bridge or on both sides, and excavate the scattered cable saddle room in the shape of a city gate hole by smooth blasting. 2. Front anchor chamber 3, front anchor chamber, anchor chamber and rear anchor chamber 7; the size of the anchor chamber is constructed according to the size of the anchor plug body and the rear anchor, and the front anchor chamber is constructed from the cable saddle chamber. The bottom begins to expand outward to the same width as the front anchor chamber, the rear anchor chamber and the anchor chamber correspond to the part width of the rear anchor, and the cross section of the anchor chamber is in the shape of a city gate or horseshoe or circle; for the front anchor chamber 3 The broken surrounding rock is reinforced by shotcrete and grouting, the anchor plug body chamber is supported by initial shotcrete, the local small conduit is grouted, the surrounding rock section is erected with steel arches to support the surrounding rock, and the surrounding rock of the rear anchor chamber 7 is shot Anchor and grouting reinforcement, main cable access hole 1, scattered cable saddle room 2, front anchor room 3 and rear anchor room 7 are lined with concrete;

(2) After the excavation of the anchor body chamber 5 and the rear anchor body 5 is completed and the bottom is cleared, accurately locate and install 27 anchor cable pipes 16 and steel bars in the rear anchor body 5 and the anchor plug chamber 5. The radial straight line extends to the front anchor surface, and the resultant force is at the center of the cable saddle 9 . The grouting pipe is pre-buried between the contact surface of the anchor body 5 and the rock mass 13, the rear anchor surface formwork is installed, the micro-expanded concrete is poured in layers and integrated, and the curing concrete is formed by the anchor body 5 and the rear anchor body 6. The one-piece anchor plug body.

(3) According to the design drawings and construction stakeout, make and install steel bars in the front anchor 4, pre-embed steel pipes with an inner diameter of φ15cm at the drilling site, and the number of holes is 82, and then pour concrete. After the strength of the concrete reaches the design strength, pass the drilling rig. The anchor cable hole 13 is drilled from the embedded steel pipe to the rear anchor surface, during which the rock mass with broken rock mass and poor integrity is grouted and strengthened, so as to improve the integrity and bearing capacity of the rock mass.

(4) Install the anchor cable 10 in the anchor cable hole 13, install the anchor cable tube 10 outside the front anchor body 4 to the front anchor chamber 3 in the rock mass, and then fill the enlarged part of the front anchor chamber 3 with reinforced concrete, The front anchor chamber reinforcement 17 is formed.

(5) Excavate the foundation of the scattered cable saddle 9 in the scattered cable saddle room 2, pour the reinforced concrete base of the scattered cable saddle 9, install the scattered cable saddle 9 after reaching the design strength, and then pull the main cable 8 of the suspension bridge into, through the scattered cable The saddle 9 is divided into 109 main cable strands 11, and the anchor cables 10 are connected to the main cable strands 11 one by one with an anchor connector;

(6) After the concrete of the anchor plug body 5 reaches the design strength, install the P-type anchor on the surface of the rear anchor body 6, start from the central anchor cable, and stretch the anchor cable layer by layer symmetrically to the outer ring, and a single anchor cable reaches its design. After loading, the anchors 14 are used to anchor to the anchor plug body until all the anchor cables are tensioned and anchored, and finally the anti-corrosion and lubricating oil body of the anchor cables is poured into the anchor cable pipe 16 .

In this embodiment, the anchor plug body with the smaller cross-sectional size in the anchorage is wrapped by the rock mass, and the anchor plug body is separated from the front anchor body, which retains the bearing mechanism of the traditional tunnel anchor. Under the action of the back anchor, the tunnel anchor and the rock mass anchor can bear together, the outer edge of the back anchor increases the bearing area of the anchor, and the stress diffusion effect of the arc body overcomes the fact that the plate (beam) anchor only uses positive The limitation of the front rock mass bearing reduces the stress concentration of the surrounding rock and further expands the bearing range of the surrounding rock. The composite anchorage can be built in the surrounding rock with poor lithology. Although there are a large number of anchor cable holes, it is less than the traditional tunnel anchor hole excavation and concrete amount, the project cost is low, the construction period is short, and the construction risk is small.

The above description is only an embodiment of the present invention, and its description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims (6)

1. The utility model provides a suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure which characterized in that: the composite anchorage structure comprises a main cable access hole (1) arranged in a bridge site area of a suspension bridge, a scattered cable saddle chamber (2), a front anchor chamber (3) and a rear anchor chamber (7) which are formed by sequentially constructing the main cable access hole (1), a front anchor solid (4), an anchor plug body (5), a rear anchor body (6) and a plurality of anchor cables (10) are arranged between the front anchor chamber (3) and the rear anchor chamber (7), the front anchor solid (4) is arranged on the front anchor surface of the anchor plug body (5), the area of the front anchor solid is larger than that of the front anchor surface of the anchor plug body (5), the rear anchor body (6) is arranged on the rear anchor surface of the anchor plug body (5), the area of the rear anchor solid is larger than that of the rear anchor surface of the anchor plug body (5), and the plurality of anchor cables (10) pass through rock masses (5) and (13) around the anchor plug body (5) from the front anchor body (4) and are fixed on the rear anchor body (6) through an anchorage device (14); main cables (8) of the suspension bridge are led into the cable-scattering saddle chamber (2) from the main cable access hole (1) and then are scattered into main cable strands (11) with the same number as the anchor cables (10) through the cable-scattering saddle (9), and each main cable strand (11) is connected with the corresponding anchor cable (10) through the anchoring connector (12).

2. The suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure of claim 1, characterized in that: the cross section of the anchor plug body (5) is in an urban portal shape, a horseshoe shape or a circular shape, and the cross section area of the anchor plug body is gradually increased from the front anchor surface to the rear anchor surface to form a wedge-shaped body with a small front part and a large rear part; the anchor plug body (5) and the rear anchor body (6) form a tunnel anchor, the front anchor body (4) is separated from the anchor plug body (5), and the front anchor body, the rear anchor body (6) and rock mass (13) around the anchor plug body (5) form a rock mass anchor wrapped outside the tunnel anchor under the action of the anchor cable (10).

3. The suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure of claim 1 or 2, characterized in that: the cross sections of the front anchor body (4) and the rear anchor body (6) are the same as the cross section of the anchor plug body (5), the anchor plug body (5) and the rear anchor body (6) are of an integrated reinforced concrete structure, the front anchor body (4) is arranged around the front side of the front anchor surface of the anchor plug body (5), and the rear anchor body (6) is connected with the anchor plug body (5) through an arc-shaped or hemispherical curved surface body.

4. The suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure of claim 2, characterized in that: backfilling concrete in a region of the front anchor chamber (3) corresponding to the front anchor solid (4) and larger than the front anchor surface of the anchor plug body (5) to form a front anchor chamber reinforcing body (17); the anchor cables (10) are uniformly distributed in an annular shape in a rock mass (13) between the anchor plug body (5) and the outer edge connecting lines of the front anchor body (4) and the rear anchor body (6) on the periphery of the anchor plug body (5), and form a rock mass anchor wrapped outside the tunnel anchor with the rock mass (13) on the periphery of the anchor plug body (5) and between the front anchor body (4) and the outer edge connecting lines of the rear anchor body (6); anchor cable pipes (16) are pre-buried in the anchor plug body (5), anchor cable holes (15) are formed in the front anchor body (4), rock mass (13) around the anchor plug body (5), the rear anchor body (6) and the front anchor chamber reinforcing body (17), the anchor cable pipes (16) are installed in the anchor cable holes (15), the anchor cable pipes (16) in the rock mass (13) and the anchor cable pipes (16) in the front anchor chamber reinforcing body (17) are connected in the front anchor chamber reinforcing body (17) in a fillet or arc tangent mode, and a plurality of anchor cables (10) penetrate through the anchor plug body (5) and the rock mass (13) around the front anchor body (4) and the anchor plug body (5) respectively and then are fixed on the rear anchor body (6) through the anchor (14).

5. The suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure of claim 2, characterized in that: the anchor cables (10) penetrate through the anchor cable pipes and the anchor cable holes to the rear anchor chamber (7) and are anchored on the rear anchoring body (6) through anchor devices, the front ends of the anchor cables (10) in the tunnel anchor are fixed on the front anchor surface of the tunnel anchor through anchor devices (14), the anchor cables (10) in the rock anchor are fixed on the front anchor chamber reinforcing body (17), and each main cable strand (11) is connected with the corresponding anchor device (14) through an anchoring connector (12); the front anchor chamber reinforcing body (17) is a reinforcing structure formed by backfilling reinforced concrete after the main cable strands (11) and the anchor cables (10) are connected on the front end face of the front anchor body (4).

6. A construction method of a suspension bridge tunnel anchor and rock mass anchor combined type anchorage structure is characterized by comprising the following specific steps:

(1) determining the position of a front anchor chamber according to a design drawing and construction lofting, excavating a main cable access hole on a single-side or double-side mountain slope of the suspension bridge, and excavating an urban portal-shaped cable saddle scattering chamber, a front anchor solid chamber, an anchor body chamber and a rear anchor chamber by smooth blasting; the size of the anchor body chamber is constructed according to the size of the anchor plug body and the size of the rear anchor body, the front anchor chamber is expanded from the bottom of the cable saddle chamber to be consistent with the width of the front anchor solid chamber, the rear anchor chamber is consistent with the width of the part of the anchor body chamber corresponding to the rear anchor body, and the cross section of the anchor body chamber is in an urban portal shape, a horseshoe shape or a circular shape;

(2) carrying out shotcreting and grouting reinforcement on the broken surrounding rock of the front anchor chamber, carrying out primary shotcreting support on the front anchor solid chamber and the anchor body chamber, grouting local small ducts, erecting a steel arch frame on the surrounding rock section to support the surrounding rock, carrying out shotcreting and grouting reinforcement on the surrounding rock of the rear anchor chamber, and lining a main cable with concrete for connecting the main cable into the hole, the cable saddle chamber, the front anchor chamber and the rear anchor chamber;

(3) after the excavation of the anchor body chamber and the rear anchor chamber is finished and the bottom is cleaned, an anchor cable pipe and a steel bar are accurately positioned and installed in the anchor body chamber, the anchor cable pipe extends to the front anchor surface in a radial straight line mode, and the resultant force point is located in the center of the cable scattering saddle; embedding a grouting pipe between the anchor plug body and the rock contact surface, installing a rear anchor surface template, integrally pouring micro-expansion concrete in a layered mode, vibrating tightly, and curing the concrete to form an integrated anchor body structure consisting of the anchor plug body and a rear anchor body;

(4) according to design drawings and construction layout, indoor reinforcing steel bars of the front anchoring body are manufactured and installed, steel pipes are embedded in drilling positions, concrete is poured, after the strength of the concrete reaches design strength, anchor cable holes are drilled from the embedded steel pipes to the rear anchoring face through a drilling machine, and the rock body is broken and is reinforced through grouting during the process, so that the integrity and the bearing capacity of the rock body are improved.

(5) Installing an anchor cable in the anchor cable hole, installing an anchor cable pipe outside the front anchoring body in the rock mass to a front anchoring chamber, and backfilling a region, corresponding to the front anchoring body, of the front anchoring chamber, which is larger than the front anchoring surface of the anchor plug body by using reinforced concrete to form a front anchoring chamber reinforcing body;

(6) excavating a cable saddle foundation in a cable saddle dispersing chamber, pouring a cable saddle reinforced concrete base, installing a cable saddle after the cable saddle reaches the design strength, drawing a main cable of the suspension bridge, dispersing the cable saddle into main cable strands with the same number as the anchor cables, and connecting the anchor cables with the main cable strands one by using anchor connectors;

(7) after the anchor plug body concrete reaches the design strength, an anchor is installed on the surface of the rear anchor body, the anchor cables are symmetrically stretched from the center anchor cable to the outer ring layer by layer, after a single anchor cable reaches the design load, the single anchor cable is anchored to the anchor plug body by the anchor until all the anchor cables are stretched and anchored, and finally, oil bodies for corrosion prevention and lubrication of the anchor cables are poured into the anchor cable pipes, so that the construction of the composite anchor structure is completed.

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