ECC-poured honeycomb sandwich weak surrounding rock supporting structure and connecting method

Abstract

A honeycomb sandwich weak surrounding rock supporting structure poured with ECC comprises a secondary lining layer, a waterproof layer, a steel arch frame, a primary support sprayed concrete layer and feet-lock bolts, and the steel arch frame is formed by connecting a net structure arch frame and a traditional strip-shaped steel frame. The reticular structure arch frame is formed by vertically and crossly connecting a plurality of sections of honeycomb sandwich annular lines and a plurality of sections of honeycomb sandwich longitudinal lines through tenon-and-mortise structures; the multiple sections of traditional strip-shaped steel frames are connected with the ends of the multiple sections of honeycomb sandwich circumferential lines on the two sides of the net-shaped structure arch frame through connecting devices respectively; engineering cement-based composite materials are poured into the multiple sections of honeycomb sandwich annular lines and the multiple sections of honeycomb sandwich longitudinal lines. According to the technology, the annular lines and the longitudinal lines are connected through the tenon-and-mortise structures, a net-shaped supporting structure is formed, and the connecting performance between supports is enhanced; the ECC is poured into the honeycomb sandwich-shaped steel structure, so that the supporting structure has certain deformation resistance and rigidity for preventing the surrounding rock from being deformed excessively, and the safety and stability of the tunnel structure can be effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering, and in particular to a honeycomb sandwich soft surrounding rock support structure infused with ECC (engineered cement-based composite material) and a connection method. Background Art

[0002] The increase in tunnel construction projects has led to a gradual increase in the number of complex geological types encountered; weak surrounding rock is a geological condition often encountered during tunnel construction. Its existence poses a huge safety hazard to tunnel construction. If the excavation measures are not appropriate, it will often cause landslides and even cause engineering construction safety accidents. Therefore, support devices are needed to support the weak surrounding rock of the tunnel.

[0003] At present, the steel arch frame used in the initial support is connected by a single strip steel. After the steel arch frame is connected into a ring, it is covered with sprayed concrete to form the first layer of initial support. This support form has low rigidity and weak connection performance in the longitudinal direction. When the local force of the soft surrounding rock tunnel is too large, it is easy to cause the single ring arch frame to become unstable and damaged, causing engineering safety accidents. Therefore, the reasonable support structure of the soft surrounding rock tunnel needs to have good connection performance in the circumferential and longitudinal directions, and be able to deform in coordination with the surrounding rock on the basis of having a certain rigidity. In order to increase the support contact area, improve stability and deformation resistance, some construction units have developed honeycomb sandwich tunnel support structures. For example, Chinese patent: A rectangular steel arch frame tunnel support structure combining a honeycomb sandwich structure and steel, application number: 202210338069.X, application date: 2022.04.01, abstract: The present invention discloses a rectangular steel arch frame tunnel support structure combining a honeycomb sandwich structure and steel, comprising a secondary lining layer, a waterproof layer, an initial support shotcrete layer, an upper multi-section honeycomb sandwich structure and a rectangular steel arch frame combining steel, a bottom multi-section traditional strip steel arch frame, and a connection device between locking anchor rods and the steel arch frame. The rectangular steel arch frame formed by combining the upper multi-section honeycomb sandwich structure and the steel section has a rectangular surface, which increases the contact area between the steel arch frame and the surrounding rock, and the surface is a layer of honeycomb sandwich structure. The honeycomb sandwich structure is deformed by the stress of the surrounding rock mass, so that the energy of the surrounding rock can be released. The deformation of the steel arch frame under different tunnel conditions can be met by adjusting the number of honeycomb layers in the honeycomb sandwich structure, so that the support structure has both the ability to coordinate deformation with the surrounding rock and the rigidity to prevent excessive deformation of the surrounding rock, which can effectively solve the problem of deformation and damage in the initial support of high-ground stress soft rock large deformation tunnels.

[0004] Applied research has found that in the structure disclosed in the above document, screw holes need to be drilled in the metal plate, and the supporting structure is connected by bolts by construction workers, which has the disadvantages of slow construction, easy installation omissions and stress concentration. Summary of the invention

[0005] The purpose of the present invention is to provide a soft surrounding rock support structure and a connection method of a honeycomb sandwich filled with ECC in order to solve the problems existing in the prior art. On the one hand, the present technology forms a mesh support structure by connecting multiple sections of honeycomb sandwich annular lines and multiple sections of honeycomb sandwich longitudinal lines by mortise and tenon overlap, thereby increasing the support area of ​​the existing support structure, effectively controlling the deformation of the surrounding rock, and preventing excessive deformation of the local surrounding rock; on the other hand, the strength and stiffness of the lining structure are increased by combining the honeycomb sandwich structure with ECC, and the ductility of the support structure damage is increased.

[0006] The present invention is achieved by adopting the following technical solutions: The invention discloses an ECC-injected honeycomb sandwich soft rock support structure, comprising a secondary lining layer, a waterproof layer, a steel arch frame, a primary support shotcrete layer and a locking anchor rod. The support structure is composed of a secondary lining layer, a waterproof layer and a primary support shotcrete layer from the outside to the inside. The steel arch frame is arranged in the primary support shotcrete layer. The locking anchor rod is connected to the steel arch frame and anchored in the surrounding rock by insertion. The steel arch frame is composed of a mesh structure arch frame and a traditional strip steel frame. The mesh structure arch frame is formed by vertically cross-connecting a plurality of sections of honeycomb sandwich annular lines and a plurality of sections of honeycomb sandwich longitudinal lines through a mortise and tenon structure. The plurality of sections of honeycomb sandwich annular lines are bent along their length according to the tunnel hole size. The plurality of sections of traditional strip steel frames are respectively connected to the ends of the plurality of sections of honeycomb sandwich annular lines on both sides of the mesh structure arch frame through connecting devices. The connection device is prefabricated by modifying the traditional connection structure, and one end is provided with a mortise and tenon connection with the end of the multi-segment honeycomb sandwich annular line on both sides of the mesh structure arch, and the other end is fixedly connected with the traditional strip steel frame; the multi-segment honeycomb sandwich annular line and the multi-segment honeycomb sandwich longitudinal line are poured with ECC. The traditional support structure is connected by bolts by construction workers, which has the disadvantages of slow construction, easy defects and stress concentration. In the present invention, each structure is connected by mortise and tenon overlap, eliminating these disadvantages, and there is no need to drill screw holes in the metal plate, reducing the damage to the plate caused by stress concentration, filling ECC in the honeycomb sandwich structure, and the honeycomb sandwich structure and ECC are deformed together by force, with high bearing capacity and good ductility.

[0007] Further preferred: the multi-section honeycomb sandwich circumferential line is composed of a honeycomb sandwich structure rod with a circumferential type I mortise and tenon connection structure at both ends and a longitudinal type II lap structure at the middle, and the multi-section honeycomb sandwich longitudinal line is composed of a honeycomb sandwich structure rod with a longitudinal type III mortise and tenon connection lap structure at both ends, and the longitudinal type III mortise and tenon connection lap structure is mortise-connected with the longitudinal type II lap structure.

[0008] Further preferred: the honeycomb sandwich structure rod comprises two upper and lower metal plates, between which a type I multi-level semi-honeycomb layer and a type II multi-level honeycomb layer are sandwiched; the type I multi-level semi-honeycomb layer is located at the outermost side of the honeycomb sandwich structure rod, comprising half of a honeycomb cell, the honeycomb cell is a hollow structure, and the cross section is a regular hexagon; the type II multi-level honeycomb layer is located inside the honeycomb sandwich structure rod, comprising a plurality of honeycomb cells, the honeycomb cells are a hollow structure, the cross section is a regular hexagon, and a plurality of circular holes are provided on the vertical cell wall and the oblique cell wall to facilitate the flow of ECC in each honeycomb cell. In the honeycomb sandwich structure, increasing the number of multi-level honeycomb layers will greatly increase the rigidity of the honeycomb sandwich structure.

[0009] Further preferred: the annular type I mortise and tenon connection structure arranged at both ends of the honeycomb sandwich structure rod is a protruding type I multi-level semi-honeycomb layer and a protruding type II multi-level semi-honeycomb layer, that is, the length of the type I multi-level semi-honeycomb layer and the protruding type II multi-level semi-honeycomb layer of the honeycomb sandwich structure rod is longer than the metal plate.

[0010] Further preferred: the longitudinal type II overlap structure is a structure in which tenons are arranged on the honeycomb sandwich structure rod, and the height of the honeycomb-like layer of the longitudinal type II overlap structure is only half of the height of the honeycomb-like layer of the honeycomb sandwich structure rod.

[0011] Further preferred: the longitudinal type III mortise and tenon connection overlap structure arranged at both ends of the honeycomb sandwich structure rod is a protruding type I multi-level quasi-semi-honeycomb layer and a protruding type II multi-level quasi-semi-honeycomb layer, that is, the length of the type I multi-level quasi-semi-honeycomb layer and the protruding type II multi-level quasi-semi-honeycomb layer of the honeycomb sandwich structure rod is longer than the metal plate, and the height of the honeycomb layer of the longitudinal type III mortise and tenon connection overlap structure is only half of the height of the honeycomb layer of the honeycomb sandwich structure rod.

[0012] Further preferred: the ECC (engineered cement-based composite material) is made of cement, sand, fly ash, blast furnace slag, silica fume, polycarboxylic acid high-efficiency water reducer, polyethylene fiber and water, and requires a 28-day compressive strength of not less than 50 MPa, a tensile strength of not less than 6 MPa, and an ultimate tensile strain of not less than 5%.

[0013] The connection method of the ECC-injected honeycomb sandwich weak surrounding rock support structure is to first inject ECC from the annular type I mortise and tenon connection structure into the multi-segment honeycomb sandwich annular line from bottom to top, and when the casting surface reaches the longitudinal type II overlap structure, two multi-segment honeycomb sandwich longitudinal lines connected by mortise and tenon are overlapped onto the longitudinal type II overlap structure, and ECC is injected into the multi-segment honeycomb sandwich longitudinal lines from the longitudinal type III mortise and tenon connection overlap structures at both ends; the casting process is layered from bottom to top according to the casting port position of the multi-segment honeycomb sandwich structure rod, and when the casting surface reaches the casting port, the current casting port is blocked, and then another casting port is cast until the casting of the entire ring is completed.

[0014] Compared with the prior art, the advantages of the present invention are: 1. The circumferential line and longitudinal line of the steel arch frame are prefabricated components with simple structure and easy manufacturing. They are connected by mortise and tenon joints to form a mesh support structure. The construction process is simple and there is no need to drill screw holes in the metal plate, which reduces the damage to the plate caused by stress concentration, enhances the connection performance between the circumferential supports, increases the support area of ​​the existing support structure, and can effectively control the deformation of the surrounding rock.

[0015] 2. The steel arch frame is composed of a multi-section honeycomb sandwich structure infused with ECC and a multi-section strip steel arch frame at the bottom, which gives full play to the advantages of ECC's high ductility, high rigidity, good durability and strong crack width control ability, increases the rigidity and ductility of the steel arch frame, and can better resist the deformation of the surrounding rock; it has the effect of increasing the strength and rigidity of the primary support structure of the tunnel and effectively controlling the displacement deformation, and can increase the ductility of the steel arch frame structure damage; the circular holes on the vertical cell walls and oblique cell walls in the type II multi-level semi-honeycomb layer can make it more convenient for ECC to flow and fill in the honeycomb layer and ensure its density, while the type I multi-level semi-honeycomb layer can prevent ECC from flowing out from both sides, reducing the waste of ECC during grouting; it is suitable for the characteristics of large deformation in the upper part and small deformation in the lower part of the tunnel structure, which can save materials and improve economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The schematic diagram of the structure of the soft surrounding rock support structure with honeycomb core and ECC poured in it; Figure 2 It is a schematic diagram of the connection of a plurality of sections of honeycomb sandwich core circumferential lines and a plurality of sections of honeycomb sandwich core longitudinal lines; Figure 3 It is a structural schematic diagram of a multi-section honeycomb sandwich circumferential line; Figure 4 It is a schematic diagram of the structure of a multi-section honeycomb sandwich longitudinal line; The names corresponding to the numbers in the figure are: 1. Secondary lining layer; 2. Waterproof layer; 3. Multi-section honeycomb sandwich circumferential line; 31. Circumferential type I mortise and tenon connection structure; 32. Longitudinal type II lap joint structure; 33. Honeycomb sandwich structure; 331. Type I multi-level semi-honeycomb layer; 332. Type II multi-level semi-honeycomb layer; 333. Metal plate; 4. Multi-section honeycomb sandwich longitudinal line; 41. Longitudinal type III mortise and tenon connection lap joint structure; 5. Traditional strip steel frame; 6. Primary support shotcrete layer; 7. Locking foot anchor rod; 8. Connection device. DETAILED DESCRIPTION

[0017] The technical solutions in the invention are clearly and completely described below in conjunction with the embodiments. The described embodiments are only a part of the present invention, rather than all the embodiments. Example

[0018] A honeycomb sandwich soft surrounding rock support structure with ECC injection, comprising a secondary lining layer 1, a waterproof layer 2, a steel arch frame, a primary support shotcrete layer 6 and a locking anchor rod 7. The support structure is composed of the secondary lining layer 1, the waterproof layer 2 and the primary support shotcrete layer 6 from the outside to the inside. The steel arch frame is arranged in the primary support shotcrete layer 6. The locking anchor rod 7 is connected to the steel arch frame and anchored in the surrounding rock by insertion. The steel arch frame is composed of a mesh structure arch frame and a traditional strip steel frame 5. The mesh structure arch frame is formed by vertically cross-connecting a multi-section honeycomb sandwich annular line 3 and a multi-section honeycomb sandwich longitudinal line 4 through a mortise and tenon structure. The multi-section honeycomb sandwich annular line 3 is curved along its length according to the tunnel hole size; the multi-section traditional strip steel frame 5 is respectively connected to the end of the multi-section honeycomb sandwich annular line 3 on both sides of the mesh structure arch frame through a connecting device 8. The connecting device 8 is prefabricated by modifying the traditional connecting structure, and one end of it is provided with a mortise and tenon connection with the end of the multi-segment honeycomb sandwich annular line 3 on both sides of the mesh structure arch frame, and the other end is fixedly connected to the traditional strip steel frame 5; ECC is poured into the multi-segment honeycomb sandwich annular line 3 and the multi-segment honeycomb sandwich longitudinal line 4.

[0019] The multi-section honeycomb sandwich annular line 3 is composed of a honeycomb sandwich structure rod 33 with an annular type I mortise and tenon connection structure 31 at both ends and a longitudinal type II lap structure 32 in the middle. The multi-section honeycomb sandwich longitudinal line 4 is composed of a honeycomb sandwich structure rod 33 with longitudinal type III mortise and tenon connection lap structures 41 at both ends. The longitudinal type III mortise and tenon connection lap structure 41 is mortise-and-tenon connected to the longitudinal type II lap structure 32.

[0020] The honeycomb sandwich structure rod 33 includes two upper and lower metal plates 333, and a type I multi-level semi-honeycomb layer 331 and a type II multi-level honeycomb layer 332 are sandwiched between the upper and lower metal plates 333; the type I multi-level semi-honeycomb layer 331 is located at the outermost side of the honeycomb sandwich structure rod 33, including half of a honeycomb cell, the honeycomb cell is a hollow structure, and the cross section is a regular hexagon; the type II multi-level honeycomb layer 332 is located inside the honeycomb sandwich structure rod 33, including multiple honeycomb cells, the honeycomb cells are hollow structures, the cross section is a regular hexagon, and multiple circular holes are provided on the vertical cell walls and the oblique cell walls to facilitate the flow of ECC in each honeycomb cell. In the honeycomb sandwich structure, increasing the number of layers of the multi-level honeycomb layer will greatly increase the rigidity of the honeycomb sandwich structure.

[0021] The annular type I mortise and tenon connection structure 31 arranged at both ends of the honeycomb sandwich structure rod 33 is a protruding type I multi-level semi-honeycomb layer 331 and a protruding type II multi-level semi-honeycomb layer 332, that is, the length of the type I multi-level semi-honeycomb layer 331 and the protruding type II multi-level semi-honeycomb layer 332 of the honeycomb sandwich structure rod 33 is longer than the metal plate 333.

[0022] The longitudinal II-type overlap structure 32 is a structure in which a tenon is arranged on the honeycomb sandwich structure rod 33 , and the height of the honeycomb-like layer of the longitudinal II-type overlap structure 32 is only half of the height of the honeycomb-like layer of the honeycomb sandwich structure rod 33 .

[0023] The longitudinal type III mortise and tenon connection overlap structure 41 arranged at both ends of the honeycomb sandwich structure rod 33 is a protruding type I multi-level semi-honeycomb layer 331 and a protruding type II multi-level semi-honeycomb layer 332, that is, the length of the type I multi-level semi-honeycomb layer 331 and the protruding type II multi-level semi-honeycomb layer 332 of the honeycomb sandwich structure rod 33 is longer than the metal plate 333, and the height of the honeycomb layer of the longitudinal type III mortise and tenon connection overlap structure 41 is only half of the height of the honeycomb layer of the honeycomb sandwich structure rod 33.

[0024] The ECC (engineered cement-based composite material) is prepared from cement, sand, fly ash, blast furnace slag, silica fume, polycarboxylic acid high-efficiency water-reducing agent, polyethylene fiber and water. The prepared engineering cement-based composite material (ECC) is required to have a 28-day compressive strength of not less than 50 MPa, a tensile strength of not less than 6 MPa, and an ultimate tensile strain of not less than 5%.

[0025] The ECC pouring is firstly pouring ECC from the annular type I mortise and tenon connection structure 31 into the multi-segment honeycomb sandwich annular line 3 from bottom to top, and when the pouring surface reaches the longitudinal type II overlap structure 32, two multi-segment honeycomb sandwich longitudinal lines 4 connected by mortise and tenon connection are overlapped onto the longitudinal type II overlap structure 32, and ECC is poured into the multi-segment honeycomb sandwich longitudinal lines 4 from the longitudinal type III mortise and tenon connection overlap structures 41 at both ends; the pouring process is layered pouring from bottom to top according to the pouring port position of the multi-segment honeycomb sandwich structure rod, and when the pouring surface reaches the pouring port, the current pouring port is blocked, and then another pouring port is poured until the whole ring is poured.

[0026] The above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A soft rock support structure of a perfused ECC honeycomb sandwich, comprising a secondary lining layer (1), a waterproof layer (2), a steel arch frame, a primary support shotcrete layer (6) and a locking anchor rod (7), wherein the support structure is, from the outside to the inside, a secondary lining layer (1), a waterproof layer (2) and a primary support shotcrete layer (6), the steel arch frame is arranged in the primary support shotcrete layer (6), and the locking anchor rod (7) is connected to the steel arch frame and inserted and anchored in the surrounding rock, characterized in that: The steel arch frame is composed of a mesh structure arch frame and a traditional strip steel frame (5) connected together. The mesh structure arch frame is formed by vertically cross-connecting a plurality of sections of honeycomb sandwich annular lines (3) and a plurality of sections of honeycomb sandwich longitudinal lines (4) through a mortise and tenon structure. The plurality of sections of honeycomb sandwich annular lines (3) are curved along their length according to the size of the tunnel hole. The plurality of sections of traditional strip steel frames (5) are respectively connected to the ends of the plurality of sections of honeycomb sandwich annular lines (3) on both sides of the mesh structure arch frame through connecting devices (8). ECC is poured into the plurality of sections of honeycomb sandwich annular lines (3) and the plurality of sections of honeycomb sandwich longitudinal lines (4).

2. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 1 is characterized by: The multi-segment honeycomb sandwich circumferential line (3) is composed of honeycomb sandwich structure rods (33) having circumferential type I mortise and tenon connection structures (31) at both ends and a longitudinal type II overlap structure (32) at the middle. The multi-segment honeycomb sandwich longitudinal line (4) is composed of honeycomb sandwich structure rods (33) having longitudinal type III mortise and tenon connection overlap structures (41) at both ends. The longitudinal type III mortise and tenon connection overlap structures (41) are connected to the longitudinal type II overlap structures (32) by mortise and tenon connection.

3. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 2 is characterized by: The honeycomb sandwich structure rod (33) comprises an upper and lower metal plate (333), between which a type I multi-level semi-honeycomb layer (331) and a type II multi-level honeycomb layer (332) are sandwiched; the type I multi-level semi-honeycomb layer (331) is located at the outermost side of the honeycomb sandwich structure rod (33), and comprises half of a honeycomb cell, the honeycomb cell is a hollow structure, and the cross section is a regular hexagon; the type II multi-level honeycomb layer (332) is located inside the honeycomb sandwich structure rod (33), and comprises a plurality of honeycomb cells, the honeycomb cells are a hollow structure, and the cross section is a regular hexagon, and a plurality of circular holes are provided on the vertical cell wall and the oblique cell wall.

4. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 3 is characterized by: The annular type I mortise and tenon connection structures (31) arranged at both ends of the honeycomb sandwich structure rod (33) are a protruding type I multi-level semi-honeycomb layer (331) and a protruding type II multi-level semi-honeycomb layer (332), that is, the length of the type I multi-level semi-honeycomb layer (331) and the protruding type II multi-level semi-honeycomb layer (332) of the honeycomb sandwich structure rod (33) is longer than the metal plate (333).

5. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 3 is characterized by: The longitudinal type II overlap structure (32) is a structure in which a tenon is arranged on the honeycomb sandwich structure rod (33), and the height of the honeycomb-like layer of the longitudinal type II overlap structure (32) is only half of the height of the honeycomb-like layer of the honeycomb sandwich structure rod (33).

6. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 2 is characterized by: The longitudinal type III mortise and tenon joint overlap structures (41) arranged at both ends of the honeycomb sandwich structure rod (33) are a protruding type I multi-level quasi-semi-honeycomb layer (331) and a protruding type II multi-level quasi-semi-honeycomb layer (332), that is, the length of the type I multi-level quasi-semi-honeycomb layer (331) and the protruding type II multi-level quasi-semi-honeycomb layer (332) of the honeycomb sandwich structure rod (33) is longer than the metal plate (333), and the height of the quasi-honeycomb layer of the longitudinal type III mortise and tenon joint overlap structures (41) is only half of the height of the quasi-honeycomb layer of the honeycomb sandwich structure rod (33).

7. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 1 is characterized by: The ECC is composed of cement, sand, fly ash, blast furnace slag, silica fume, polycarboxylic acid high-efficiency water reducing agent, polyethylene fiber and water, and requires a 28-day compressive strength of not less than 50 MPa, a tensile strength of not less than 6 MPa, and an ultimate tensile strain of not less than 5%.

8. The ECC-injected honeycomb sandwich weak surrounding rock support structure according to claim 1, characterized in that: The pouring of ECC is to first pour ECC from the circumferential type I mortise and tenon connection structure (31) from bottom to top into the multi-segment honeycomb sandwich circumferential line (3); when the pouring surface reaches the longitudinal type II overlap structure (32), two multi-segment honeycomb sandwich longitudinal lines (4) connected by mortise and tenon connection are overlapped onto the longitudinal type II overlap structure (32); and ECC is poured into the multi-segment honeycomb sandwich longitudinal lines (4) from the longitudinal type III mortise and tenon connection overlap structures (41) at both ends; the pouring process is layered pouring from bottom to top according to the pouring port position of the multi-segment honeycomb sandwich structure rod; when the pouring surface reaches the pouring port, the current pouring port is blocked, and then another pouring port is poured until the pouring of the entire ring is completed.

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