CN112252169A - Hollow box-rock anchor combined light ground anchor bridge abutment and construction process thereof - Google Patents
Hollow box-rock anchor combined light ground anchor bridge abutment and construction process thereof Download PDFInfo
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- CN112252169A CN112252169A CN202011295017.6A CN202011295017A CN112252169A CN 112252169 A CN112252169 A CN 112252169A CN 202011295017 A CN202011295017 A CN 202011295017A CN 112252169 A CN112252169 A CN 112252169A
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
- E01D19/02—Piers; Abutments ; Protecting same against drifting ice
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
Abstract
The invention relates to the field of bridge structures, in particular to a hollow box-rock anchor combined light ground anchor abutment and a construction process thereof. The anchor hole is internally provided with a fiber reinforced composite anchor rod, and the vertical prestressed hole and the transverse prestressed hole are both provided with fiber reinforced composite ribs. The combined ground anchor abutment system organically combines the hollow box-shaped ground anchor with the rock anchor, effectively improves the pulling resistance, the sliding resistance and the overturning resistance of the shallow hollow box-shaped ground anchor by utilizing the rock anchor capable of deeply embedding a rock layer, and also overcomes the defects of overlarge anchor body volume and mountain excavation volume, difficult crack control, poor durability, higher manufacturing cost and the like of the traditional gravity type abutment.
Description
Technical Field
The invention relates to the field of bridge structures, in particular to a hollow box-rock anchor combined light ground anchor bridge abutment and a construction process thereof.
Background
The ground anchor type bridge abutment is a key stressed member of the large-span anchor type cable-stayed bridge and must safely bear huge uplift force and horizontal force transmitted by a ground anchor stay cable. Currently, common ground anchor structures can be divided into solid gravity anchors, box-type hollow box anchors and rock anchors.
The solid gravity anchor balances the huge tension transmitted by the inhaul cable by using the dead weight of the masonry volume of the anchor body, has wider application range in the traditional cable bearing bridge, but has the defects of overlarge masonry volume, difficult crack control and higher manufacturing cost; the hollow box-shaped ground anchor is an improvement of a solid gravity anchor, changes the interior of an anchor body from a solid structure into a cavity structure, and fills sand and stone in the cavity as a ballast weight so as to effectively reduce the volume of a masonry. The working principle of the two traditional ground anchors is consistent, the pull force of the inhaul cable is completely resisted by the gravity of the anchor body, and the defects that the mountain excavation square volume and the masonry consumption are too large, the cracking is difficult to control and the manufacturing cost is high due to the fact that the size of the anchor body is too large exist.
The traditional rock anchor system adopts high-strength steel wires or steel strands as anchor rods, common cement mortar as underground anchoring media and a common prestressed tendon anchor as an anchoring system of an exposed tensioning end of the anchor rods. However, the service life of the traditional steel and the common cement mortar is far from being coordinated with the design life of a super-huge bridge for hundreds of years due to low strength and poor corrosion resistance, and the use effect of the traditional steel and the common cement mortar is far from meeting the requirements of stability and durability under the long-term load action.
Disclosure of Invention
The invention provides a hollow box-rock anchor combined light ground anchor abutment and a construction process thereof, aiming at solving the technical problems of difficult crack control, poor stability and durability of a ground anchor and solving the problems, the hollow box-rock anchor combined light ground anchor abutment organically combines the hollow box-rock anchor with the rock anchor, effectively improves the anti-pulling, anti-sliding and anti-overturning capabilities of a shallow hollow box-rock anchor by utilizing the rock anchor capable of deeply embedding a rock layer, and overcomes the defects of overlarge anchor body volume and mountain excavation volume, difficult crack control, poor durability, higher manufacturing cost and the like of the traditional gravity type abutment; meanwhile, fiber reinforced plastic ribs are used as prestressed ribs of the hollow box-shaped ground anchor and an anchor rod of the rock anchor, and an ultra-high performance cement-based material is used as a grouting material of a prestressed hole of the hollow box-shaped ground anchor and a bonding medium of the anchor rod of the rock anchor, so that the structural durability problem of the traditional rock anchor caused by steel bar corrosion and grouting body aging is solved.
The invention relates to a hollow box-rock anchor combined light ground anchor abutment, which comprises a hollow box-shaped ground anchor and a plurality of rock anchors, wherein a plurality of cavities are formed in the hollow box-shaped ground anchor, fillers are arranged in the cavities, a plurality of anchor holes, a plurality of vertical prestressed holes and a plurality of transverse prestressed holes are reserved in the hollow box-shaped ground anchor, anchor rods of the rock anchors are arranged in the anchor holes, vertical prestressed ribs are arranged in the vertical prestressed holes, transverse prestressed ribs are arranged in the transverse prestressed holes, and ultrahigh-performance cement-based composite materials are filled between the vertical prestressed ribs and the vertical prestressed holes as well as between the transverse prestressed ribs and the transverse prestressed holes.
Further, the anchor eye in set up and hold the pipe, the stock of rock anchor is located the holding pipe that corresponds, holds and pours into grout material between pipe and the anchor eye.
Furthermore, the cavity is not in contact with the anchor hole, the vertical prestressed hole and the transverse prestressed hole.
Furthermore, the plurality of anchor holes and the plurality of vertical prestressed holes are vertically arranged along two sides of the width direction of the box body.
Furthermore, the plurality of anchor holes and the plurality of vertical prestressed holes are arranged in a staggered mode.
Furthermore, the transverse prestressed holes are horizontally formed, and the transverse prestressed holes are not in contact with the anchor holes and the vertical prestressed holes.
Furthermore, a plurality of fixed pipes are arranged in the hollow box-shaped ground anchor bridge abutment, and the anchor holes are inner holes of the fixed pipes.
Furthermore, a pre-buried pipe is arranged in the vertical prestressed hole and/or the transverse prestressed hole, and grouting materials are filled between the vertical prestressed tendons and/or the transverse prestressed tendons and the corresponding pre-buried pipes.
A construction process of a hollow box-rock anchor combined light ground anchor bridge abutment comprises the following steps:
firstly, determining the loads to be borne by the box body and the rock anchor respectively;
determining the raw materials and the proportion of the common concrete, and taking the common concrete as the material of the box body;
determining the raw materials and the proportion of the ultra-high performance cement-based composite material, and taking the raw materials and the proportion as grouting materials of the vertical prestressed hole and the transverse prestressed hole;
determining the specific types of the vertical prestressed tendons and the horizontal prestressed tendons;
determining the size of a hollow box-shaped ground anchor bridge abutment and the number of vertical prestressed tendons and transverse prestressed tendons;
thirdly, excavating and drilling a foundation pit according to design requirements, wherein the size of the foundation pit is 40-60cm larger than that of the hollow box-shaped ground anchor abutment;
drilling an anchor hole;
binding a steel bar framework of the box body, pouring concrete to form the box body, and reserving an anchor hole, a vertical prestressed hole and a transverse prestressed hole in the box body;
tensioning the vertical prestressed tendons and the transverse prestressed tendons;
pouring an ultrahigh-performance cement-based composite material into the anchor hole, the vertical prestressed hole and the transverse prestressed hole;
and (6) installing a rock anchor.
Further, the construction process of the hollow box-rock anchor combined light ground anchor bridge abutment comprises the following steps:
fixed pipe is pre-buried in the framework of steel reinforcement to set up in fixed pipe and hold the pipe, fixed pipe and hold and pour into the grout material between the pipe.
The invention has the beneficial effects that the characteristics of the hollow box-shaped ground anchor and the rock anchor are integrated, the box-shaped ground anchor and the rock anchor are combined, the defects of overlarge anchor body volume and mountain excavation volume, difficult crack control, higher manufacturing cost and the like of the traditional hollow box-shaped ground anchor are overcome, and the hollow box-shaped ground anchor has stronger anti-pulling, anti-sliding and anti-overturning capabilities than the traditional hollow box-shaped ground anchor. The invention adopts the fiber reinforced composite material with the characteristics of light weight, high strength, large specific modulus, corrosion resistance, excellent fatigue resistance, low relaxation and the like as the vertical prestressed tendon and the transverse prestressed tendon of the hollow box-shaped ground anchor, can improve the effective prestress of a prestressed system and improve the durability of the bridge abutment of the hollow box-shaped ground anchor. The invention adopts the ultra-high performance cement-based composite material as the grouting material of the vertical prestressed hole and the transverse prestressed hole, so that the prestress can be uniformly applied to the hollow box-shaped ground anchor. The high-performance material prestress system formed by combining the fiber reinforced composite material and the ultrahigh-performance cement-based composite material has the advantages of reliability, high efficiency, wide applicability and strong engineering practicability, and can effectively overcome the defects of difficult guarantee of effective prestress, poor corrosion resistance and fatigue resistance and the like of the traditional steel reinforcement prestress system.
Drawings
FIG. 1 is a front view of the present invention;
FIG. 2 is a top view of FIG. 1;
FIG. 3 is a schematic cross-sectional view of a rock anchor;
fig. 4 is a schematic diagram of a construction process of the rock anchor.
In the figure, the device comprises a box body 1, a box body 2, a rock anchor 3, a vertical prestressed tendon 4, a transverse prestressed tendon 5, a cavity 6, an anchor hole 7, a fixed pipe 8 and a containing pipe.
Detailed Description
As shown in the attached drawings 1-4, the invention discloses a hollow box-rock anchor combined light ground anchor abutment, which comprises a hollow box-shaped ground anchor 1 and a plurality of rock anchors 2, wherein a plurality of cavities 5 are formed in the hollow box-shaped ground anchor 1, fillers are arranged in the cavities 5, a plurality of anchor holes 6, a plurality of vertical prestressed holes and transverse prestressed holes are reserved in the hollow box-shaped ground anchor 1, and rock strata below the hollow box-shaped ground anchor 1 are deeply embedded into the anchor holes 6. The anchor rod of the rock anchor 2 is arranged in the anchor hole 6, the vertical prestressed tendons 3 are arranged in the vertical prestressed holes, and the transverse prestressed tendons 4 are arranged in the transverse prestressed holes. The ultra-high performance cement-based composite material is filled in anchor holes 6 in the anchor rod and the rock stratum, between the vertical prestressed tendons and the vertical prestressed holes and between the transverse prestressed tendons 4 and the transverse prestressed holes. And no bonding medium is arranged between the anchor rod and the anchor hole of the hollow box-shaped ground anchor. The super-high performance cement-based material is active powder concrete or high-density ultrafine particle uniform distribution material. The structure integrates the characteristics of the hollow box-shaped ground anchor and the rock anchor, combines the box-shaped ground anchor with the rock anchor, overcomes the defects of overlarge anchor body volume, overlarge mountain excavation volume, difficult crack control, higher manufacturing cost and the like of the traditional hollow box-shaped ground anchor, and has stronger uplift, skid and overturn resistance compared with the traditional hollow box-shaped ground anchor. The structure adopts the fiber reinforced composite material with the characteristics of light weight, high strength, large specific modulus, corrosion resistance, excellent fatigue resistance, low relaxation and the like as the vertical prestressed tendons 3 and the transverse prestressed tendons 4 of the hollow box-shaped ground anchor, so that the effective prestress of a prestress system can be improved, and the durability of the bridge abutment of the hollow box-shaped ground anchor is improved; the ultra-high performance cement-based composite material is used as the grouting material of the vertical prestressed holes, the transverse prestressed holes and the anchor holes 6, so that the prestress can be uniformly applied to the hollow box-shaped ground anchor. The structure combines the fiber reinforced composite material and the ultra-high performance cement-based composite material to form a high performance material prestress system, has the advantages of reliability and high efficiency, wide applicability and strong engineering practicability, and can effectively overcome the defects of difficult guarantee of effective prestress, poor corrosion resistance and fatigue resistance and the like of the traditional steel reinforcement material prestress system. The connection of the rock anchor 2 and the hollow box-shaped ground anchor 1 can be realized by a nut or other fixing devices. The filler can increase the weight of the hollow box-shaped ground anchor 1, thereby improving the tension of the inhaul cable which can be balanced, and correspondingly reducing the volume of the hollow box-shaped ground anchor 1, thereby reducing the volume of the anchor body and the amount of the mountain excavation. The fiber reinforced plastic rib of the rock anchor system is also used as the vertical prestressed rib of the box-shaped ground anchor web plate, which is beneficial to the crack control of the hollow box-shaped ground anchor concrete.
The anchor eye 6 in set up and hold pipe 8, the stock of rock anchor 2 is located the holding pipe 8 that corresponds, holds and pours the grout material between pipe 8 and the anchor eye 6. Grouting materials are poured between the accommodating pipes 8 and the anchor holes 6 so as to prevent the anchor holes 6 from weakening the shear-resistant bearing capacity of the box body 1. The accommodating tube can be made of PVC tube.
The cavity 5 is not in contact with the anchor hole 6, the vertical prestressed hole and the transverse prestressed hole. The structure can stagger the rock anchor 2, the vertical prestressed tendon 3 and the transverse prestressed tendon 4 with the cavity 5, and is beneficial to the connection of the rock anchor 2, the vertical prestressed tendon 3 and the transverse prestressed tendon 4 with the hollow box-shaped ground anchor 1.
The plurality of anchor holes 6 and the plurality of vertical prestressed holes are vertically arranged along two sides of the width direction of the hollow box-shaped ground anchor 1. The structure is beneficial to the rock anchors 2 in the anchor holes 6 to be uniformly distributed on the hollow box-shaped ground anchor 1, and the huge uplifting force and horizontal force transmitted by the inhaul cable are effectively balanced.
The plurality of anchor holes 6 and the plurality of vertical prestressed holes are arranged in a staggered mode. The structure can lead the rock anchor 2 and the vertical prestressed tendon 3 to be arranged in a staggered way, and effectively improves the combination degree of the hollow box-shaped ground anchor 1 and the rock anchor 2.
The transverse prestressed holes are horizontally formed, and the transverse prestressed holes are not in contact with the anchor holes 6 and the vertical prestressed holes. The structure can lead the transverse prestressed tendons 4, the rock anchors 2 and the vertical prestressed tendons 3 to be arranged in a staggered way, and is beneficial to effectively fixing the transverse prestressed tendons 4.
A plurality of fixing pipes 7 are arranged in the hollow box-shaped ground anchor 1, and the anchor holes 6 are inner holes of the fixing pipes 7. The fixed pipe 7 is a pre-buried pipe, and a corrugated pipe can be adopted.
The vertical prestressed holes and/or the transverse prestressed holes are internally provided with embedded pipes, and grouting materials are filled between the vertical prestressed holes and/or the transverse prestressed holes and the corresponding embedded pipes. Grouting materials are poured between the embedded pipe and the vertical prestressed holes and/or the transverse prestressed holes so as to prevent the vertical prestressed holes and/or the transverse prestressed holes from weakening the shear-resistant bearing capacity of the hollow box-shaped ground anchor 1. The embedded pipe can be a PVC pipe.
The filler is sand and/or stone. The sand and/or the stone can be obtained locally so as to save cost and protect the environment, and the sand and/or the stone has larger weight, so that the hollow box-shaped ground anchor 1 filled with the filler has stronger anti-pulling, anti-sliding and anti-overturning capabilities than the traditional hollow box-shaped ground anchor.
In specific embodiment 1, a construction process of a hollow box-rock anchor combined light ground anchor abutment comprises the following steps:
firstly, determining the loads to be borne by the hollow box-shaped ground anchor 1 and the rock anchor 2 respectively;
determining the raw materials and the proportion of the common concrete, and taking the common concrete as the material of the hollow box-shaped ground anchor 1;
determining the raw materials and the proportion of the ultra-high performance cement-based composite material, and taking the raw materials and the proportion as grouting materials of the vertical prestressed hole and the transverse prestressed hole;
determining materials of the vertical prestressed tendons 3 and the transverse prestressed tendons 4;
determining the raw materials and the proportion of the ultra-high performance cement-based composite material, and taking the raw materials and the proportion as an anchoring bonding medium;
determining the size of the hollow box-shaped ground anchor 1 and the number of the vertical prestressed tendons 3 and the number of the transverse prestressed tendons 4;
determining the number and arrangement mode of anchor rods of the rock anchor 2, the length A of an overground anchoring section, the length B of an overground free section of the anchor rods, the length C of an underground free section, the length D of the underground anchoring section and the length E of a terminal device;
thirdly, excavating and drilling a foundation pit according to design requirements, wherein the size of the foundation pit is 40-60cm larger than that of the box body 1;
drilling an anchor hole in the foundation pit;
binding a steel bar framework of the hollow box-shaped ground anchor 1, pouring concrete to form the hollow box-shaped ground anchor 1, and reserving an anchor hole 6, a vertical prestressed hole and a transverse prestressed hole in the hollow box-shaped ground anchor 1;
installing a rock anchor 2;
pouring an underground anchoring section bonding medium-ultra-high performance cement-based composite material;
stretching the anchor rod and connecting the anchor rod with the hollow box-shaped ground anchor 1
Tensioning the vertical prestressed tendons 3 and the transverse prestressed tendons 4;
and pouring the ultra-high performance cement-based composite material into the vertical prestressed hole and the transverse prestressed hole.
The reserved anchor hole 6 in the hollow box-shaped ground anchor 1 comprises:
In specific embodiment 2, a construction process of a hollow box-rock anchor combined light ground anchor abutment comprises the following steps:
(1) determining the loads to be borne by the hollow box-shaped ground anchor 1 and the rock anchor 2 respectively;
(2) determining the material of the hollow box-shaped ground anchor 1, the prestressed tendon material and the mounting hole grouting material: determining the raw materials and the proportion of the common concrete, and taking the common concrete as the material of the hollow box-shaped ground anchor 1; determining the specific type of the fiber reinforced composite material rib, and taking the specific type as a vertical prestressed rib 3 and a transverse prestressed rib 4; determining the raw materials and the proportion of the ultra-high performance cement-based composite material, and taking the raw materials and the proportion as grouting materials of the vertical prestressed hole and the transverse prestressed hole;
(3) determining the anchor rod material and the anchoring bonding medium of the rock anchor 2: determining the specific type of the fiber reinforced composite material rib, taking the fiber reinforced composite material rib as an anchor rod material, determining the raw materials and the proportion of the ultrahigh-performance cement-based composite material, and taking the ultrahigh-performance cement-based composite material rib as an anchoring bonding medium;
(4) determining a connection mode between the hollow box-shaped ground anchor 1 and the rock anchor 2; the rock anchor is connected with the hollow box-shaped ground anchor 1 through an anchor rod and a locking nut. And reserved anchor holes 6 are arranged for each anchor rod by utilizing a fixed pipe 7 embedded in a web plate of the hollow box-shaped ground anchor. And a containing pipe 8 is arranged outside each bundle of anchor rod reinforcing steel bars in the web area of the hollow box-shaped ground anchor 1, and the containing pipe 8 is not bonded with the anchor rods. Grouting material is poured between the accommodating pipe 8 and the fixing pipe 7 so as to prevent the shear bearing capacity of the web plate from being weakened due to the fact that the anchor holes 6 are oversized. The anchor rods passing through the webs of the hollow box-shaped earth anchor 1 can be regarded as unbonded vertical prestressing tendons.
(5) Designing a hollow box-shaped ground anchor: determining the size of the hollow box-shaped ground anchor 1, the weight of fillers in the cavity, and the number and types of the vertical prestressed tendons 3 and the transverse prestressed tendons 4;
(6) designing a rock anchor: and carrying out material property test research based on the determined anchor rod material and the determined bonding medium. And respectively obtaining the interface bonding strength between the fiber reinforced composite material plastic bar anchor rod and the ultrahigh-performance cement-based material and between the ultrahigh-performance cement-based material and the surrounding rock through a drawing test and a push-out test. Then, based on the test results, a preliminary dimension of the rock anchor 2 is preliminarily drawn up. The key design content comprises the number and arrangement mode of anchor rods of the rock anchor 2, the length A of an overground anchoring section, the overground free section length B of the anchor rods, the length C of an underground free section, the length D of the underground anchoring section and the length E of a tail end device;
(7) prefabricating and installing in an anchor rod factory: arranging accommodating pipes 8 outside each bundle of anchor rod reinforcing steel bars in the area needing to penetrate through the box-shaped ground anchor web, uniformly distributing a plurality of centering frames in the middle section of the fiber reinforced composite plastic rib anchor rod, sequentially penetrating one end of the fiber reinforced composite plastic rib anchor rod through a compression ring, a positioning piece and a ground end anchor cylinder of an anchor, penetrating the fiber reinforced composite plastic rib anchor rod through a corresponding anchor hole 6, and positioning and fixing the fiber reinforced composite plastic rib anchor rod at the rear end of the ground upper end anchor cylinder; the other end of the fiber reinforced composite plastic bar anchor rod is provided with a ground lower end anchorage device, and the structure and the installation sequence of the ground lower end anchorage device are basically the same as those of the ground upper end anchorage device; then pouring the ultra-high performance cement base material into the cavity to the positioning piece ends of the anchor drum at the upper end and the anchor drum at the lower end of the ground, slightly vibrating and compacting after the slurry overflows, fixing the positioning piece, screwing the compression ring, and finally maintaining the ultra-high performance cement base material until the ultra-high performance cement base material reaches the required strength;
(8) and (3) carrying out ex-factory inspection on the anchor rod: after the fiber reinforced composite plastic bar anchor rod is prefabricated and installed in a factory, the fiber reinforced composite plastic bar anchor rod is a fiber reinforced plastic bar-anchor assembly part with anchors arranged at two ends. In order to ensure that the anchor rod can be effectively anchored by the anchoring systems at the two ends, the fiber reinforced plastic rib-anchor assembly part needs to be subjected to tensioning inspection before leaving a factory. And selecting tensioning equipment and a field according to the number and the length of the anchor rods. Before tensioning, the fiber reinforced plastic rib-anchor assembly part needs to be centered so that the anchor cylinders at two ends are positioned on the same horizontal line. An anchoring nut is arranged on the outer side of the anchor cylinder at one end, so that the end is fixed; and pushing the anchor cylinder at the other end by using a jack to apply tension. If the tensile force reaches the designed load, the bearing capacity of the anchoring ends at the two ends can be judged to be qualified;
(9) the combined ground anchor abutment is constructed, installed, tensioned and anchored in site: fig. 4 shows a field construction process of the lightweight ground anchor abutment with the hollow box-rock anchor combination, which comprises the following specific steps: digging a foundation pit and drilling an anchor hole: excavating and drilling a foundation pit according to design requirements, wherein the size of the foundation pit is 40-60cm larger than that of the hollow box-shaped ground anchor 1, and the depth of a hole site is 40-60cm larger than the length of the fiber reinforced plastic bar anchor rod; secondly, pouring concrete of the hollow box-shaped ground anchor 1, tensioning the vertical prestressed tendons 3 and the transverse prestressed tendons 4, and pre-embedding the fillers in the cavity: when binding a common steel bar framework of the hollow box-shaped ground anchor 1, utilizing a corrugated pipe as a vertical prestressed tendon 3 and a transverse prestressed tendon 4, and an anchor rod preformed hole penetrating through a web plate area of the hollow box-shaped ground anchor 1; meanwhile, reserving a position for an overground anchoring end of the rock anchor 2; after the prestressed tendons are tensioned, pouring an ultrahigh-performance cement-based composite material into holes reserved in the vertical prestressed tendons 3 and the transverse prestressed tendons 4; checking whether each anchor rod is damaged or not, timely repairing the damaged anchor rod protection level accessories, installing accessories such as an underground anchoring end conical cap and the like and an anchor rod suspension device, and then putting the fiber reinforced plastic rib-anchor assembly and the grouting pipe into the drill hole to be in place; fourthly, pouring the prepared ultra-high performance cement-based material into the lower section of the hole site through a grouting pipe, and then curing the pouring material until the strength of the pouring material is designed to be removed; tensioning the anchor rod: after the bonding medium of the underground anchoring section reaches the strength required by the design, the integral tensioning is carried out on each fiber reinforced plastic bar anchor rod by using a feed-through jack, and when the tensioning force reaches the design requirement, a locking nut can be screwed down to lock the ground upper end anchorage device; sealing the anchor: before sealing the anchor, pouring an underground free section bonding medium, namely common cement mortar; after the common cement mortar reaches the strength required by the design, pouring an ultrahigh-performance cement-based composite material between the accommodating pipe 8 and the fixed pipe 7; then, an end cover and a protective cover are installed to seal the ground anchoring end.
The above implementation steps have the following features: the ultra-high performance cement-based composite material is used as a bonding anchoring medium for an overground anchoring section, an overground free section, an underground end anchoring section and a tail end device of the fiber reinforced plastic rib anchor rod. The bonding media in the anchor cylinder of the overground anchoring section of the fiber reinforced plastic rib anchor rod and the anchor cylinder of the tail end device are both poured and anchored by using an ultra-high performance cement-based composite material suitable for factory production, and the ultra-high performance cement-based composite material grouting material takes quartz sand with 40-70 meshes as an aggregate and is cured by a hot water bath at the temperature of more than 80 ℃ for 3-5 days, so that the strength can reach 130 MPa. Bonding media of the overground free section, the underground free section and the underground end anchoring section of the fiber reinforced plastic rib anchor rod are all poured by adopting ultrahigh-strength cement-based composite material slurry suitable for an on-site pressure grouting machine, the ultrahigh-strength cement-based composite material adopts non-aggregate grouting material, a nano material is added to improve the flowing property of the grouting material, and the strength of the grouting material can reach 110MPa after the karst cave maintenance simulating the underground environment is adopted for 12-16 days.
The vertical prestressed tendons and the horizontal prestressed tendon preformed holes of the hollow box-shaped ground anchor are filled with ultrahigh-strength cement-based composite material slurry suitable for a field pressure grouting machine. The ultrahigh-strength cement-based composite material selects the aggregate-free grouting material, the nano material is added to improve the flow property of the grouting material, and the strength can reach 110MPa after natural curing for 12-16 days.
The ground anchoring section anchorage device and end device anchorage device of the fiber reinforced plastic rib anchor rod are designed and manufactured aiming at the characteristics of fiber reinforced composite plastic and ultra-high performance cement-based materials, and the characteristics comprise: in a rock anchor system, a plurality of fiber reinforced plastic bar anchor rods are arranged according to the principle of dispersion and symmetry, so that concentrated stress or uneven stress of the bars is avoided, and the reasonable clear distance of each fiber reinforced plastic bar anchor rod is more than one time of the diameter of the bar; the inner walls of the anchor cylinder of the ground anchoring section or the anchor cylinder of the tail end device are both provided with conical cavities, slurry is in a wedge shape after being poured, the bonding anchoring effect of the slurry can be improved, and the reasonable taper range of the conical cavities is 3-15 degrees; the fiber reinforced plastic rib anchor rods at the anchoring section of the anchor cylinder are also provided with inclination angles, the reasonable inclination angle range is 2-12 degrees, the anchoring effect is improved, and meanwhile, the shearing of the rib materials can be avoided; the length of the anchor cylinder is determined by considering the bonding strength of the two materials, the average bonding strength of the multiple fiber reinforced composite plastic ribs and the ultrahigh-performance cement-based material adopted in the embodiment reaches about 20MPa, the theoretical anchoring length is about 250mm, and a certain safety coefficient needs to be considered in the length design of the anchor cylinder; the outer wall of the anchor cylinder of the overground anchoring section or the outer wall of the anchor cylinder of the tail end device is provided with external threads, the external threads are used for fixing and applying jacking force when assemblies in a plant are tensioned, and locking nuts are screwed for load locking after the field rock anchor is tensioned.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. The utility model provides a formula box-rock anchor combination formula light-duty earth anchor abutment that open side which characterized in that: including cavity formula box earth anchor (1) and several rock bolt (2), several cavity (5) are seted up to cavity formula box earth anchor (1) inside, set up the filler in cavity (5), reserve several anchor eye (6) in cavity formula box earth anchor (1), several vertical prestressed hole and the horizontal prestressed hole of several, set up the stock of rock bolt (2) in anchor eye (6), set up vertical prestressed tendons (3) in the vertical prestressed hole, set up horizontal prestressed tendons (4) in the horizontal prestressed hole, all pour into super high performance cement base combined material between vertical prestressed tendons (3) and vertical prestressed hole and between horizontal prestressed tendons (4) and horizontal prestressed hole.
2. A diabolo-box-rock-anchor combination lightweight earth anchor abutment as claimed in claim 1, wherein: the anchor hole (6) in set up and hold pipe (8), the stock of rock anchor (2) is located the holding pipe (8) that corresponds in, fills the grout between holding pipe (8) and anchor hole (6).
3. A diabolo-box-rock-anchor combination lightweight earth anchor abutment as claimed in claim 1, wherein: the cavity (5) is not in contact with the anchor hole (6), the vertical pre-stressed hole and the transverse pre-stressed hole.
4. A diabolo-box-rock-anchor combination lightweight earth anchor abutment as claimed in claim 1, wherein: the plurality of anchor holes (6) and the plurality of vertical prestressed holes are vertically arranged along two sides of the width direction of the hollow box-shaped ground anchor (1).
5. A lightweight earth-anchored abutment of the cavity-type box-rock anchor combination type as claimed in claim 1 or 4, wherein: the plurality of anchor holes (6) and the plurality of vertical prestressed holes are arranged in a staggered mode.
6. A diabolo-box-rock-anchor combination lightweight earth anchor abutment as claimed in claim 1, wherein: the transverse prestressed holes are horizontally formed, and the transverse prestressed holes are not in contact with the anchor holes (6) and the vertical prestressed holes.
7. A diabolo-box-rock-anchor combination lightweight earth anchor abutment as claimed in claim 2, wherein: a plurality of fixing pipes (7) are arranged in the hollow box-shaped ground anchor (1) to form corresponding anchor holes (6).
8. A diabolo-box-rock-anchor combination lightweight earth anchor abutment as claimed in claim 1, wherein: the vertical prestressed holes and/or the transverse prestressed holes are internally provided with embedded pipes, and grouting materials are filled between the vertical prestressed tendons (3) and/or the transverse prestressed tendons (4) and the corresponding embedded pipes.
9. The construction process of the lightweight ground anchor abutment of the hollow box-rock anchor combination type as claimed in claim 1, wherein: the method comprises the following steps:
firstly, determining the loads to be borne by the hollow box-shaped ground anchor (1) and the rock anchor (2) respectively;
secondly, determining the raw materials and the proportion of the common concrete, and taking the common concrete as the material of the hollow box-shaped ground anchor (1);
determining the raw materials and the proportion of the ultra-high performance cement-based composite material, and taking the raw materials and the proportion as grouting materials of the vertical prestressed hole and the transverse prestressed hole;
determining materials of the vertical prestressed tendons (3) and the transverse prestressed tendons (4);
determining the raw materials and the proportion of the ultra-high performance cement-based composite material, and taking the raw materials and the proportion as an anchoring bonding medium;
determining the size of the hollow box-shaped ground anchor (1), and determining the number of vertical stress tendons (3) and transverse stress tendons (4);
determining the number and arrangement mode of anchor rods of the rock anchor (2), the length A of an overground anchoring section, the overground free section length B of the anchor rods, the underground free section length C, the underground anchoring section length D and the length E of a tail end device;
thirdly, excavating and drilling a foundation pit according to design requirements, wherein the size of the foundation pit is 40-60cm larger than that of the hollow box-shaped ground anchor (1);
drilling an anchor hole in the foundation pit;
binding a steel bar framework of the hollow box-shaped ground anchor (1), pouring concrete to form the hollow box-shaped ground anchor (1), and reserving an anchor hole (6), a vertical prestressed hole and a transverse prestressed hole in the hollow box-shaped ground anchor (1);
installing a rock anchor (2);
pouring an underground anchoring section bonding medium-ultra-high performance cement-based composite material;
stretching the anchor rod, and connecting the anchor rod with the hollow box-shaped ground anchor (1);
tensioning the vertical prestressed tendons (3) and the transverse prestressed tendons (4);
and pouring the ultra-high performance cement-based composite material into the vertical prestressed hole and the transverse prestressed hole.
10. The process for constructing a lightweight earth anchor abutment of the hollow box-rock anchor combination type as claimed in claim 9, wherein: the reserved anchor hole (6) in the hollow box-shaped ground anchor (1) comprises:
fixed pipe (7) are pre-buried in steel reinforcement framework to set up in fixed pipe (7) and hold pipe (8), fixed pipe (7) and hold and pour into the grout between pipe (8).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113502744A (en) * | 2021-06-15 | 2021-10-15 | 中交第二航务工程局有限公司 | Ground anchor type abutment construction method |
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| US5208932A (en) * | 1990-04-25 | 1993-05-11 | Societe Centrale D'etudes Et De Realisations Routieres-Scetauroute | Cable-stay bridge and method for construction thereof |
| US20060200920A1 (en) * | 2005-03-11 | 2006-09-14 | Sang-Hyo Kim | Method of constructing partially earth-anchored cable-stayed bridge using thermal prestressing technique |
| CN208023388U (en) * | 2017-11-30 | 2018-10-30 | 中国电建集团西北勘测设计研究院有限公司 | A kind of only tower unequal span partly anchor stayed-cable bridge |
| CN111254966A (en) * | 2020-03-16 | 2020-06-09 | 浙江省交通规划设计研究院有限公司 | Mountain abutment and pier column foundation structure and construction method thereof |
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| US5208932A (en) * | 1990-04-25 | 1993-05-11 | Societe Centrale D'etudes Et De Realisations Routieres-Scetauroute | Cable-stay bridge and method for construction thereof |
| US20060200920A1 (en) * | 2005-03-11 | 2006-09-14 | Sang-Hyo Kim | Method of constructing partially earth-anchored cable-stayed bridge using thermal prestressing technique |
| CN208023388U (en) * | 2017-11-30 | 2018-10-30 | 中国电建集团西北勘测设计研究院有限公司 | A kind of only tower unequal span partly anchor stayed-cable bridge |
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| CN113502744A (en) * | 2021-06-15 | 2021-10-15 | 中交第二航务工程局有限公司 | Ground anchor type abutment construction method |
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