Shallow-buried excavation large-section subway station supporting device and using method

Abstract

The shallow-buried excavation large-section subway station supporting device comprises an anchoring head, a grouting pipe, a plurality of bearing plates, a plurality of anchor cables and a tensioning disc, the anchoring head is used for being buried and fixed in an anchor hole, a grouting cavity is formed in the anchoring head, the anchoring head is provided with a plurality of grouting holes, the grouting holes penetrate through the anchoring head in the thickness direction, and the bearing plates are arranged on the bearing plates. The grouting cavity is communicated with the anchor hole; one end of the grouting pipe is communicated with the grouting cavity, and the other end is positioned at the orifice of the anchor hole; all the bearing plates are coaxially arranged on the grouting pipe in a sleeving mode at intervals, and the bearing plate closest to the anchoring head is fixedly connected with the anchoring head; every two adjacent bearing plates are connected through a plurality of anchor cables, and the ends, away from the anchoring heads, of the anchor cables extend out of the anchor holes; the tensioning disc is arranged at the hole opening of the anchor hole and connected with all the anchor cables, the diameter of the tensioning disc is larger than the hole diameter of the hole opening of the anchor hole, and the tensioning disc is used for tensioning all the anchor cables. The problem that an existing support is not ideal in effect when coping with super-large sections and complex geological conditions can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of side wall support for dark-excavated large-span subway stations, and in particular to a shallowly buried dark-excavated large-section subway station support device. Background Art

[0002] In the construction of subway stations, the shallow buried tunneling method has become a widely used method because it can effectively control surface settlement and surrounding rock stability. Especially for situations with abundant groundwater and complex geological conditions, the shallow buried tunneling method ensures the safety and economy of construction through technical means such as advanced support, improved strata, and grouting reinforcement.

[0003] The strata in the above scene are, from top to bottom, the artificial fill layer of the Quaternary Holocene and the sedimentary rock layer of the Shaximiao Formation of the Middle Jurassic. The rock and soil characteristics of each layer are described as follows:

[0004] (1) Quaternary Holocene:

[0005] Miscellaneous fill: As the station is located in the city center, human activities are intense, and the miscellaneous fill is mostly mottled, mainly domestic garbage and construction waste, with a slightly dense structure and slightly wet. It is mainly distributed in the demolition area of ​​the residential area and along the original roads, with a small distribution range.

[0006] Plain fill soil: purple-brown, mainly clay soil intercalated with sandstone and mudstone (blocks), with block content of 25-45%, particle size of 200-1000mm, crushed stone content of 10-30%, particle size of 20-200mm, structure is generally slightly dense to medium dense, slightly wet;

[0007] (2) Middle Jurassic Shaximiao Formation: It is a set of fluvial-lacustrine clastic rocks in a strongly oxidizing environment, consisting of positive sedimentary rhythmic layers of sandstone and mudstone of varying thickness, including:

[0008] Sandy mudstone: mainly purple-red in color, with clay minerals as the main mineral component, silt mud structure, medium-thick layered structure, moderately weathered rock mass with undeveloped cracks, relatively complete rock mass, and relatively hard rock. Its saturated compressive strength is between 4.56 and 9.83 MPa, and the standard value of saturated compressive strength is 6.67 MPa. Combined with the actual situation of the entire layer on the site, it is comprehensively determined to be soft rock, and the basic quality grade of the rock mass is IV.

[0009] Sandstone: Gray to purple-gray, fine to medium-grained, thick-layered structure; the main mineral components are quartz and feldspar, containing a small amount of mica and clay minerals, mostly calcareous cementation, partially argillaceous cementation, hard rock, relatively complete rock mass, its saturated compressive strength is between 20.50 and 37.00 MPa, and the standard value of saturated compressive strength is 26.50 MPa. Combined with the actual situation of the whole layer of the site, it is comprehensively determined that it is a relatively soft rock, and the basic quality grade of the rock mass is IV. The thickness of the strongly weathered zone of bedrock along the line is generally 0.30 to 2.30 m. The rock mass in the strongly weathered zone of bedrock is broken, weathering fissures are developed, the rock mass is soft, and the basic quality grade of the rock mass is V.

[0010] The surrounding rock of the tunnel is mainly composed of relatively complete block mosaic structure sandy mudstone intercalated with thin sandstone. The groundwater outflow state is generally wet or drip-like (partially linear flow), and the normal unit water inflow of the tunnel is predicted to be 9.1L / min·10m. The basic classification of the surrounding rock is level IV, and the surrounding rock level is level IV after correction. The thickness of the moderately weathered bedrock at the top of the tunnel is about 26.9~37.5m, which is greater than 2.5h=26.82m. It is a deep buried tunnel with good tunneling conditions. However, through the evaluation of the stability of the tunnel arch and side walls, it is concluded that the surrounding rock of this section of the tunnel is mainly composed of medium-thick sandstone intercalated with thin sandy mudstone, and the rock formation is 290°∠6°. According to the analysis of the structural plane stereographic projection diagram: when excavating the left side of the tunnel wall, the phenomenon of block falling is prone to occur locally; after excavation, the right side wall may collapse. During tunnel excavation, the observation of the air-facing structural surface appearing on the side wall and the heading face should be strengthened, and attention should be paid to removing loose rock blocks, and monitoring and support work should be strengthened. When the tunnel vault is unsupported, it is prone to large collapse. Due to the small inclination of the rock layer, the thin layer of sandy mudstone (sandstone) remaining in the arch is prone to block falling and large collapse.

[0011] At the same time, the station is located in the city center and the construction of the station will be close to existing buildings. In order to reduce the impact of the construction of the large-span underground subway station on adjacent buildings and prevent damage to buildings due to soil displacement, high-strength support is required for the construction of the large-span underground subway station.

[0012] It can be seen from the above that the underground soil layers in the above scenarios are often uneven, and the physical and mechanical properties of different soil layers vary greatly. High-strength support is required for the above soil layers, and it is also necessary to adopt different and adaptive support parameters for different soil layers. However, for subway stations with large spans, the existing technology has limitations in the design and implementation of support structures, especially when dealing with super-large sections and complex geological conditions. The support effect is often not ideal, resulting in extended construction periods, increased costs and increased safety risks. Summary of the invention

[0013] The purpose of the present invention is to provide a shallow buried and dark excavated large-section subway station support device to solve the problem that the existing support is not ideal when dealing with super-large sections and complex geological conditions.

[0014] The present invention is achieved through the following technical solutions:

[0015] A shallow buried and dark excavated large-section subway station support device comprises: an anchor head, the anchor head is used to be buried and fixed in an anchor hole, a grouting cavity is opened inside the anchor head, the anchor head is opened with a plurality of grouting holes, the grouting holes penetrate the anchor head along the thickness direction so that the grouting cavity is connected with the anchor hole; a grouting pipe, one end of the grouting pipe is connected with the grouting cavity, and the other end is located at the orifice of the anchor hole; a plurality of bearing plates, all of which are coaxially sleeved on the grouting pipe at intervals, and a bearing plate closest to the anchor head is fixedly connected with the anchor head; a plurality of anchor cables, two adjacent bearing plates are connected by a plurality of anchor cables, and one end of the anchor cable away from the anchor head extends to the outside of the anchor hole; a tensioning disk, the tensioning disk is arranged at the orifice of the anchor hole and connected with all the anchor cables, the diameter of the tensioning disk is larger than the aperture of the orifice of the anchor hole, and the tensioning disk is used to tighten all the anchor cables.

[0016] Optionally, the number of the bearing plates is 3, including a primary bearing plate, a secondary bearing plate and a tertiary bearing plate, the primary bearing plate, the secondary bearing plate and the tertiary bearing plate are sequentially arranged in a direction away from the anchor head, and the primary bearing plate is fixedly connected to the anchor head; the primary bearing plate is provided with a plurality of primary anchor cable holes, the primary anchor cable holes penetrate the primary bearing plate in a thickness direction, all the primary anchor cable holes are provided in a circular ring shape with the grouting pipe as the axis, and the radius of the circle line where the primary anchor cable holes are located is the first radius; the secondary bearing plate is provided with a plurality of secondary Anchor cable holes, the secondary anchor cable holes penetrate the secondary bearing plate along the thickness direction, all the secondary anchor cable holes are opened in a circular ring shape with the grouting pipe as the axis, and the radius of the circle line where the secondary anchor cable holes are located is the second radius; the tertiary bearing plate is provided with a plurality of tertiary anchor cable holes, the tertiary anchor cable holes penetrate the tertiary bearing plate along the thickness direction, all the tertiary anchor cable holes are opened in a circular ring shape with the grouting pipe as the axis, and the radius of the circle line where the tertiary anchor cable holes are located is the third radius; the primary anchor cable holes, the secondary anchor cable holes and the tertiary anchor cable holes are all used for passing and anchoring the anchor cables.

[0017] Optionally, the first radius>the second radius>the third radius.

[0018] Optionally, the secondary bearing plate has multiple secondary through-holes, and all of the secondary through-holes correspond one-to-one with all of the primary anchor holes; the tertiary bearing plate has multiple tertiary through-holes, and all of the tertiary through-holes correspond one-to-one with all of the primary anchor holes and all of the secondary anchor holes.

[0019] Optionally, the anchor cables include multiple first-level anchor cables, multiple second-level anchor cables and multiple third-level anchor cables; the first-level anchor cables correspond one-to-one to the first-level anchor cable holes; the second-level anchor cables correspond one-to-one to the second-level anchor cable holes; the third-level anchor cables correspond one-to-one to the third-level anchor cable holes; one end of the first-level anchor cable is passed through and anchored in the corresponding first-level anchor cable hole, and the other end is passed through and anchored in the corresponding second-level through-hole, and then passed through the corresponding third-level through-hole, and connected to the tensioning disk; one end of the second-level anchor cable is passed through and anchored in the corresponding second-level anchor cable hole, and the other end is passed through and anchored in the corresponding third-level through-hole, and then connected to the tensioning disk; one end of the third-level anchor cable is passed through and anchored in the corresponding third-level anchor cable hole, and the other end is connected to the tensioning disk.

[0020] Optionally, the first-level anchor cable, the second-level anchor cable and the third-level anchor cable are all sheathed with PE pipes.

[0021] Optionally, the anchor cable anchoring point is located on both sides of the corresponding bearing plate and is tightly covered with a sealing cover, and the sealing cover is filled with anti-slip grease; the anchor cable anchoring point is located on the longer side of the two sides of the corresponding bearing plate and is wrapped with a sealing tape, and the sealing tape covers the corresponding end of the sealing cover.

[0022] Optionally, a positioning plate is provided between the tertiary bearing plate and the tensioning plate, the positioning plate is coaxially mounted on the grouting pipe, the positioning plate has a plurality of positioning holes, all of the positioning holes correspond one-to-one with all of the primary anchor holes, all of the secondary anchor holes and all of the tertiary anchor holes; the primary anchor cable, the secondary anchor cable and the tertiary anchor cable are respectively passed through the corresponding positioning holes.

[0023] Optionally, an end surface of the anchor head away from the bearing plate is configured as a conical surface.

[0024] A method for using a shallow buried and dark excavated large-section subway station support device comprises the following steps:

[0025] The anchor hole is drilled by a drilling rig;

[0026] Inserting the anchor head into the anchor hole until the anchor head is located at the bottom of the anchor hole;

[0027] Injecting cement mortar through the grouting pipe until the cement mortar overflows the anchor hole;

[0028] After the cement mortar reaches a first strength, installing the tensioning plate;

[0029] After the cement mortar reaches the second strength, all the anchor cables are tensioned and fixed by the tensioning disk.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The present invention provides a shallow buried dark excavation large-section subway station support device. By arranging an anchor head, the whole device can be conveniently inserted into the anchor hole. By arranging the anchor head, a grouting cavity and a grouting hole are opened, and a grouting pipe is arranged. One end of the grouting pipe is connected with the grouting cavity, and the other end is located at the hole mouth of the anchor hole. After the anchor head is inserted into the bottom of the anchor hole, cement mortar is injected into the inside through the grouting pipe, so that the cement mortar diffuses outward from the grouting cavity through the grouting hole, and gradually fills the anchor hole from the bottom, so as to gradually press out the gas and mud impurities in the anchor hole from the anchor hole, thereby ensuring the casting effect. On this basis, by arranging Multiple bearing plates are arranged to cope with the number of soil layer types, and the bearing plates are arranged at the boundaries of different soil layer types respectively. Then, multiple anchor cables are arranged to anchor two adjacent bearing plates by using the anchor cables, so as to distinguish the tensioning force of the anchor cables corresponding to the corresponding bearing plates according to the soil layer types in the future; the anchor cables are tensioned by arranging tensioning plates, and structural support is provided for fixing the tensioned anchor cables; through the mutual cooperation of the above-mentioned features, the shallow buried and dark-excavated large-section subway station support device can effectively solve the problem that the existing support is not ideal when dealing with super-large sections and complex geological conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0033] Figure 1 A schematic diagram of a shallow buried, dark-excavated, large-section subway station support device provided by an embodiment of the present invention;

[0034] Figure 2 A partially enlarged schematic diagram of a shallow buried, dark-excavated, large-section subway station support device provided by an embodiment of the present invention;

[0035] Figures 3 to 5 A schematic diagram of a three-level bearing plate of a shallow buried and dark excavated large-section subway station support device provided by an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of a positioning plate of a shallow buried and dark excavated large-section subway station support device provided in an embodiment of the present invention.

[0037] Marks and corresponding parts names in the attached drawings:

[0038] 1-anchor hole; 10-anchor head; 11-grouting cavity; 12-grouting hole; 20-grouting pipe; 30-bearing plate; 31-first-level bearing plate; 311-first-level anchor hole; 32-second-level bearing plate; 321-second-level anchor hole; 322-second-level perforation; 33-third-level bearing plate; 331-third-level anchor hole; 332-third-level perforation; 40-anchor; 401-sealing cover; 402-sealing tape; 41-first-level anchor; 42-second-level anchor; 43-third-level anchor; 50-tensioning plate; 60-positioning plate; 61-positioning hole. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0040] Please refer to Figures 1 to 6 The embodiment of the present invention provides a shallow buried dark excavation large cross-section subway station support device, comprising: an anchor head 10, the anchor head 10 is used to be buried and fixed in an anchor hole 1, a grouting cavity 11 is opened inside the anchor head 10, the anchor head 10 is opened with a plurality of grouting holes 12, the grouting holes 12 pass through the anchor head 10 along the thickness direction, so that the grouting cavity 11 is connected with the anchor hole 1; a second grouting pipe 20, one end of the grouting pipe 20 is connected with the grouting cavity 11, and the other end is located at the orifice of the anchor hole 1; a third plurality of bearing plates 30, all of the bearing plates 30 0 interval coaxial sleeve is arranged on the grouting pipe 20, and the bearing plate 30 closest to the anchor head 10 is fixedly connected to the anchor head 10; the fourth includes multiple anchor cables 40, and two adjacent bearing plates 30 are connected by multiple anchor cables 40, and one end of the anchor cable 40 away from the anchor head 10 extends to the outside of the anchor hole 1; the fifth includes a tensioning disk 50, which is arranged at the hole mouth of the anchor hole 1 and is connected to all the anchor cables 40, and the diameter of the tensioning disk 50 is larger than the aperture of the hole mouth of the anchor hole 1, and the tensioning disk 50 is used to tighten all the anchor cables 40.

[0041] The shallow buried dark excavation large-section subway station support device provided in the present embodiment can be conveniently inserted into the anchor hole 1 by setting the anchor head 10, and the grouting cavity 11 and the grouting hole 12 are opened by setting the anchor head 10, and the grouting pipe 20 is set, so that one end of the grouting pipe 20 is connected with the grouting cavity 11, and the other end is located at the hole mouth of the anchor hole 1. After the anchor head 10 is inserted into the bottom of the anchor hole 1, cement mortar is injected into the inside through the grouting pipe 20, so that the cement mortar diffuses outward from the grouting cavity 11 through the grouting hole 12, and gradually fills the anchor hole 1 from the bottom, so as to gradually press out the gas and mud impurities in the anchor hole 1 from the anchor hole 1, thereby ensuring the casting effect; on this basis, By setting a plurality of bearing plates 30, the number of soil layer types can be coped with, and the bearing plates 30 are respectively arranged at the boundaries of different soil layer types, and then by setting a plurality of anchor cables 40, two adjacent bearing plates 30 are anchored by the anchor cables 40, so as to distinguish the tensioning force of the anchor cables 40 corresponding to the corresponding bearing plates 30 according to the soil layer types in the subsequent process; by setting a tensioning plate 50, the anchor cables 40 are tensioned, and a structural support for fixing the tensioned anchor cables 40 is provided; through the mutual cooperation of the above-mentioned features, the shallow buried and dark-excavated large-section subway station support device can effectively solve the problem that the existing support is not ideal when dealing with super-large sections and complex geological conditions.

[0042] In order to further explain the specific structure of the bearing plate 30, there are three bearing plates 30, including a primary bearing plate 31, a secondary bearing plate 32 and a tertiary bearing plate 33. The primary bearing plate 31, the secondary bearing plate 32 and the tertiary bearing plate 33 are arranged in sequence in the direction away from the anchor head 10, and the primary bearing plate 31 is fixedly connected to the anchor head 10; the primary bearing plate 31 is provided with a plurality of primary anchor holes 311, and the primary anchor holes 311 penetrate the primary bearing plate 31 along the thickness direction, and all the primary anchor holes 311 are opened in a circular ring shape with the grouting pipe 20 as the axis, and the radius of the circle line where the primary anchor holes 311 are located is the first radius; the secondary bearing plate 32 A plurality of secondary anchor holes 321 are provided, and the secondary anchor holes 321 penetrate the secondary bearing plate 32 along the thickness direction, and all the secondary anchor holes 321 are provided in a circular ring shape with the grouting pipe 20 as the axis, and the radius of the circle line where the secondary anchor holes 321 are located is the second radius; a plurality of tertiary anchor holes 331 are provided on the tertiary bearing plate 33, and the tertiary anchor holes 331 penetrate the tertiary bearing plate 33 along the thickness direction, and all the tertiary anchor holes 331 are provided in a circular ring shape with the grouting pipe 20 as the axis, and the radius of the circle line where the tertiary anchor holes 331 are located is the third radius; the primary anchor hole 311, the secondary anchor hole 321 and the tertiary anchor hole 331 are all used for passing and anchoring the anchor cable 40.

[0043] In order to prevent the anchor cables 40 from being entangled with each other, the first radius>the second radius>the third radius.

[0044] In order to avoid unnecessary obstruction and friction between the anchor cable 40 and the unanchored supporting plate 30, the secondary supporting plate 32 is provided with a plurality of secondary through-holes 322, and all of the secondary through-holes 322 correspond one-to-one with all of the primary anchor cable holes 311; the tertiary supporting plate 33 is provided with a plurality of tertiary through-holes 332, and all of the tertiary through-holes 332 correspond one-to-one with all of the primary anchor cable holes 311 and all of the secondary anchor cable holes 321.

[0045] In order to further explain the anchor cable 40, the anchor cable 40 includes a plurality of primary anchor cables 41, a plurality of secondary anchor cables 42 and a plurality of tertiary anchor cables 43; the primary anchor cables 41 correspond to the primary anchor cable holes 311 one by one; the secondary anchor cables 42 correspond to the secondary anchor cable holes 321 one by one; the tertiary anchor cables 43 correspond to the tertiary anchor cable holes 331 one by one; one end of the primary anchor cable 41 is passed through and anchored to the corresponding primary anchor cable hole 311, and the other end is passed through It is arranged and anchored in the corresponding secondary through-hole 322, and then passes through the corresponding tertiary through-hole 332, and is connected to the tensioning disk 50; one end of the secondary anchor cable 42 is arranged and anchored in the corresponding secondary anchor cable hole 321, and the other end is arranged and anchored in the corresponding tertiary through-hole 332, and is then connected to the tensioning disk 50; one end of the tertiary anchor cable 43 is arranged and anchored in the corresponding tertiary anchor cable hole 331, and the other end is connected to the tensioning disk 50.

[0046] In order to prevent the anchor cables 40 from sticking to each other, the first-level anchor cable 41 , the second-level anchor cable 42 and the third-level anchor cable 43 are all sheathed with PE tubes.

[0047] In order to further improve the structural strength of the anchoring point of the anchor cable 40, the anchoring point of the anchor cable 40 located on both sides of the corresponding bearing plate 30 is tightly covered with a sealing cover 401, and the sealing cover 401 is filled with anti-slip grease; the anchoring point of the anchor cable 40 is located on the longer side of the two sides of the corresponding bearing plate 30, and the sealing tape 402 covers the corresponding end of the sealing cover 401.

[0048] In order to further avoid unnecessary adhesion or entanglement between the anchor cables 40, a positioning plate 60 is provided between the tertiary bearing plate 33 and the tensioning plate 50. The positioning plate 60 is coaxially mounted with the grouting pipe 20. The positioning plate 60 has a plurality of positioning holes 61. All of the positioning holes 61 correspond one-to-one with all of the primary anchor holes 311, all of the secondary anchor holes 321 and all of the tertiary anchor holes 331; the primary anchor cable 41, the secondary anchor cable 42, and the tertiary anchor cable 43 are respectively passed through the corresponding positioning holes 61.

[0049] In order to facilitate lowering the device, the end surface of the anchor head 10 away from the bearing plate 30 is set to be a cone surface.

[0050] The embodiment of the present invention further provides a method for using any one of the shallow buried dark excavation large cross-section subway station support devices as described above, comprising the following steps:

[0051] S1, drilling an anchor hole 1 by using a drilling rig;

[0052] S2, inserting the anchor head 10 into the anchor hole 1 until the anchor head is located at the bottom of the anchor hole 1;

[0053] S3, injecting cement mortar through the grouting pipe 20 until the cement mortar overflows the anchor hole 1;

[0054] S4, after the cement mortar reaches the first strength, installing the tensioning plate 50;

[0055] S5. After the cement mortar reaches the second strength, all the anchor cables are tensioned and fixed by the tensioning disk 50.

[0056] Specifically, the steps include:

[0057] The first step: dry drilling with a down-the-hole drill.

[0058] The second step: the drilling rig is positioned and centered, the incident angle is adjusted, and the drilling angle is 20° with the horizontal direction. After the positioning is checked and confirmed to be correct, the drilling rig is started; the drilling depth is required to be 0.5m greater than the design depth to ensure that the anchor depth meets the design requirements and serves as the sediment section; when drilling holes for anchor cables, the horizontal deviation between holes is allowed to be ±10mm, the vertical deviation is allowed to be ±50mm, the drilling inclination deviation is allowed to be ±1°, and the final hole depth should be 50cm greater than the design hole depth. The hole must be cleaned thoroughly after the hole is completed.

[0059] The third step: anchor cable production and installation. The anchor cable in the anchoring section must be kept clean and rust-free to ensure good bonding with the gripping mortar. The free section of the prestressed anchor rod should be treated with asphalt paint or PE casing after rust removal. The external anchor head should be coated with anti-corrosion materials or wrapped with concrete. The steel strand should be coated with epoxy resin for anti-corrosion, and the coating thickness should be greater than 0.3mm.

[0060] The fourth step: grouting. The anchor cable grouting adopts the return grouting from the bottom of the hole to the hole mouth. The first grouting pressure is not less than 0.4Mpa, and the second grouting pressure is not less than 1Mpa. The grouting material is a cement mortar with a water-cement ratio of 0.4-0.45, a cement-sand ratio of 1:1, and a strength of M30. The anchor cable and the steel strand are placed in the bottom of the hole at the same time, and the pipe mouth is 150mm away from the bottom of the hole. The grouting speed is controlled at about 100L / min. When the mud and impurities in the hole are replaced by the cement slurry and overflow from the hole mouth, the first grouting is completed. After the first grouting slurry reaches the initial setting strength, the second grouting is carried out, and an appropriate amount of early strength agent is added if necessary.

[0061] Step 5: The anchor and the pad should be installed coaxially with the anchor cable body. After the anchor cable body is locked, the axial angle deviation should be ≤±5°. The excess anchor cable body of the anchor head should be cut by cold cutting, and the length retained outside the anchor should be ≥5cm.

[0062] Step 6: Tensioning and locking. After the anchor cable grouting reaches the designed strength, the tensioning and locking operation can be carried out. The prestressing of the anchor cable should be prestressed according to the requirements of the drawings, and the operation must meet the following process quality requirements. The rod axis is vertical, and the axis of the jack should be kept as close to the axis of the anchor cable as possible when installing the jack.

[0063] The load is applied gradually in stages. The last tensioning will increase the load to 1.05 times the design load and be held for observation for 10 to 15 minutes. If there is no change in deformation, the anchor cable remains in its original state, and the pressure gauge pointer on the oil pump does not return, it can be unloaded to the design load and locked.

[0064] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A shallow buried and dark excavated large-section subway station support device, characterized in that: include: An anchor head (10), the anchor head (10) is used to be embedded in and fixed in an anchor hole, a grouting cavity (11) is formed inside the anchor head (10), a plurality of grouting holes (12) are formed in the anchor head (10), and the grouting holes (12) penetrate the anchor head (10) in a thickness direction so that the grouting cavity (11) is connected to the anchor hole; A grouting pipe (20), one end of which is in communication with the grouting cavity (11), and the other end of which is located at the opening of the anchor hole; A plurality of bearing plates (30), all of which are spaced and coaxially sleeved on the grouting pipe (20), and a bearing plate (30) closest to the anchor head (10) is fixedly connected to the anchor head (10); A plurality of anchor cables (40), wherein two adjacent bearing plates (30) are connected by the plurality of anchor cables (40), and one end of the anchor cable (40) away from the anchor head (10) extends outside the anchor hole; A tensioning disk (50) is arranged at the opening of the anchor hole and is connected to all the anchor cables (40). The diameter of the tensioning disk (50) is larger than the aperture of the anchor hole. The tensioning disk (50) is used to tighten all the anchor cables (40).

2. The shallow buried and dark excavated large-section subway station support device according to claim 1 is characterized in that: The number of the bearing plates (30) is three, including a primary bearing plate (31), a secondary bearing plate (32) and a tertiary bearing plate (33); the primary bearing plate (31), the secondary bearing plate (32) and the tertiary bearing plate (33) are arranged in sequence in a direction away from the anchor head (10); the primary bearing plate (31) is fixedly connected to the anchor head (10); The first-level bearing plate (31) is provided with a plurality of first-level anchor holes (311), the first-level anchor holes (311) penetrate the first-level bearing plate (31) in the thickness direction, all the first-level anchor holes (311) are provided in a circular ring shape with the grouting pipe (20) as the axis, and the radius of the circular line where the first-level anchor holes (311) are located is a first radius; The secondary bearing plate (32) is provided with a plurality of secondary anchor cable holes (321), the secondary anchor cable holes (321) penetrate the secondary bearing plate (32) in the thickness direction, all the secondary anchor cable holes (321) are formed in a circular ring shape with the grouting pipe (20) as the axis, and the radius of the circular line where the secondary anchor cable holes (321) are located is the second radius; The third-level bearing plate (33) is provided with a plurality of third-level anchor cable holes (331), the third-level anchor cable holes (331) penetrate the third-level bearing plate (33) in the thickness direction, all the third-level anchor cable holes (331) are provided in a circular ring shape with the grouting pipe (20) as the axis, and the radius of the circular line where the third-level anchor cable holes (331) are located is a third radius; The first-level anchor cable hole (311), the second-level anchor cable hole (321) and the third-level anchor cable hole (331) are all used for passing and anchoring the anchor cable (40).

3. The shallow buried and dark excavated large-section subway station support device according to claim 2 is characterized in that: The first radius>the second radius>the third radius.

4. The shallow buried and dark excavated large-section subway station support device according to claim 3 is characterized in that: The secondary bearing plate (32) is provided with a plurality of secondary through-holes (322), and all the secondary through-holes (322) correspond one-to-one to all the primary anchor cable holes (311); The third-level bearing plate (33) is provided with a plurality of third-level through holes (332), and all the third-level through holes (332) correspond one-to-one to all the first-level anchor cable holes (311) and all the second-level anchor cable holes (321).

5. The shallow buried and dark excavated large-section subway station support device according to claim 4 is characterized in that: The anchor cables (40) include a plurality of primary anchor cables (41), a plurality of secondary anchor cables (42) and a plurality of tertiary anchor cables (43); The first-level anchor cables (41) correspond to the first-level anchor cable holes (311) one by one; The secondary anchor cables (42) correspond one to one with the secondary anchor cable holes (321); The third-level anchor cables (43) correspond one to one with the third-level anchor cable holes (331); One end of the primary anchor cable (41) is passed through and anchored to the corresponding primary anchor cable hole (311), and the other end is passed through and anchored to the corresponding secondary through hole (322), and then passes through the corresponding tertiary through hole (332) and is connected to the tensioning plate (50); One end of the secondary anchor cable (42) is passed through and anchored to the corresponding secondary anchor cable hole (321), and the other end is passed through and anchored to the corresponding tertiary through hole (332), and then connected to the tensioning plate (50); One end of the tertiary anchor cable (43) is passed through and anchored to the corresponding tertiary anchor cable hole (331), and the other end is connected to the tensioning plate (50).

6. The shallow buried and dark excavated large-section subway station support device according to claim 5 is characterized in that: The first-level anchor cable (41), the second-level anchor cable (42) and the third-level anchor cable (43) are all sheathed with PE pipes.

7. The shallow buried and dark excavated large-section subway station support device according to claim 6 is characterized in that: The anchoring part of the anchor cable (40) located on both sides of the corresponding bearing plate (30) is tightly covered with a sealing cover (401), and the sealing cover (401) is filled with anti-slip grease; The anchoring point of the anchor cable (40) is located on the longer side of the two sides of the corresponding bearing plate (30), and a sealing tape (402) is wrapped around it, and the sealing tape (402) covers the end of the corresponding sealing cover (401).

8. The shallow buried and dark excavated large-section subway station support device according to claim 7 is characterized in that: A positioning plate (60) is provided between the third-level bearing plate (33) and the tensioning plate (50), the positioning plate (60) is coaxially mounted with the grouting pipe (20), the positioning plate (60) is provided with a plurality of positioning holes (61), and all the positioning holes (61) correspond one-to-one with all the first-level anchor holes (311), all the second-level anchor holes (321) and all the third-level anchor holes (331); The first-level anchor cable (41), the second-level anchor cable (42), and the third-level anchor cable (43) are respectively inserted into the corresponding positioning holes (61).

9. The shallow buried and dark excavated large-section subway station support device according to claim 8 is characterized in that: An end surface of the anchor head (10) that is away from the bearing plate (30) is arranged as a conical surface.

10. A method for using the shallow buried dark excavation large cross-section subway station support device as claimed in any one of claims 1 to 9, characterized in that: The steps include: The anchor hole is drilled by a drilling rig; Inserting the anchor head (10) into the anchor hole until the anchor head is located at the bottom of the anchor hole; Injecting cement mortar through the grouting pipe (20) until the cement mortar overflows the anchor hole; After the cement mortar reaches a first strength, the tensioning plate (50) is installed; After the cement mortar reaches the second strength, all the anchor cables are tensioned and fixed through the tensioning plate (50).

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