Unequal parameter initial support structure of super-large section tunnel

Abstract

The utility model provides a kind of super large section tunnel unequal parameter initial support structure, comprising: several steel arch segments, several steel arch segments are respectively arranged in the stratum surface of surrounding rock, and several steel arch segments are sequentially connected head to tail, to form annular frame structure for supporting surrounding rock;Several connecting pieces, several connecting pieces are respectively arranged between adjacent two steel arch segments, for fixedly connecting adjacent two steel arch segments;Several fixing pieces, respectively threaded in each steel arch segment, for fixing annular frame structure on the stratum surface of surrounding rock. Different strength grades of surrounding rock are supported by the annular frame structure formed by several steel arch segments, so that different cross sections, bearing capacity steel arch segments can be selected for different strength grades of surrounding rock, unnecessary material waste is avoided, and the problem of resource consumption and cost increase caused by excessive support is eliminated.

Description

Technical Field

[0001] This utility model relates to the field of tunnel support technology, and in particular to an unequal-parameter initial support structure for ultra-large cross-section tunnels. Background Technology

[0002] When ultra-large cross-section tunnels pass through mountains, the complexity of the geological structure often results in the coexistence of two or more types of surrounding rock with different strength grades within the same excavation section. For example, one side of the tunnel may be surrounded by Class III surrounding rock with better stability, while the other side may be surrounded by Class IV or even Class V surrounding rock with poorer stability. This significant uneven geological condition poses a severe challenge to the traditional tunnel support design concept.

[0003] In previous tunnel support designs, the core concept of "equal-parameter support" was commonly adopted. This means that within the same tunnel cross-section, the uneven distribution of stress in the surrounding rock is ignored, and uniform support parameters are used, such as steel arches with the same cross-section and spacing. This design method has inherent drawbacks: Firstly, uniform support parameters are often determined based on the overall low strength of the surrounding rock within the cross section. However, this may result in insufficient support strength in the worst sections of the surrounding rock, making it difficult to effectively suppress the deformation of the surrounding rock and posing a risk of local instability or even collapse. Secondly, in order to accommodate the weak surrounding rock within the section, strong support parameters were adopted as a whole. This means that excessive support was implemented in the originally stable and high-bearing-capacity surrounding rock section, resulting in a huge waste of support materials such as steel and concrete, and increasing the project cost. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides an unequal-parameter initial support structure for ultra-large cross-section tunnels, which solves the problems of over-support, material waste, construction redundancy, and potential safety risks in existing ultra-large cross-section tunnel support technologies.

[0005] According to an embodiment of this utility model, an initial support structure for ultra-large cross-section tunnels with unequal parameters, installed in the surrounding rock, includes: Several steel arch frame segments are respectively set on the surface of the surrounding rock strata, and the steel arch frame segments are connected end to end in sequence to form a ring frame structure for supporting the surrounding rock. Several connectors are respectively provided between two adjacent steel arch frame segments for fixing the two adjacent steel arch frame segments; Several fasteners are respectively installed on each steel arch frame segment to fix the ring frame structure to the surface of the surrounding rock strata.

[0006] Compared with existing technologies, this solution has the following advantages: A ring-shaped frame structure is formed by several steel arch segments to support surrounding rock of different strength levels. This allows for the selection of steel arch segments with different cross-sections and load-bearing capacities for different strength levels of surrounding rock. In low-strength surrounding rock sections, steel arch segments with larger cross-sections and stronger load-bearing capacities can be used, providing higher support strength and effectively suppressing surrounding rock deformation. In high-strength surrounding rock sections, steel arch segments with smaller cross-sections can be used, making full use of the stability and load-bearing capacity of the surrounding rock itself, avoiding unnecessary material waste, and eliminating the problems of resource consumption and cost increases caused by over-support. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the Class III and IV surrounding rock support structures in the embodiments of this utility model.

[0008] Figure 2 This is a schematic diagram of the surrounding rock support structure for Class IV and V in the embodiments of this utility model.

[0009] Figure 3 This is a schematic diagram of the steel plate structure in an embodiment of this utility model.

[0010] Figure 4 This is a schematic diagram of the structure after two steel arch frame segments are spliced ​​together in an embodiment of this utility model.

[0011] In the above attached figures: 1. Steel arch frame segment; 2. Connecting parts; 201. Steel plate; 202. Mounting hole; 203. Threaded rod; 204. Nut; 3. Fasteners; 4. Surrounding rock; 5. Support frame. Detailed Implementation

[0012] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0013] This utility model embodiment proposes an initial support structure for ultra-large cross-section tunnels with unequal parameters, installed in the surrounding rock 4, comprising: Several steel arch frame segments 1 are respectively set on the surface of the surrounding rock 4, and the several steel arch frame segments 1 are connected end to end in sequence to form a ring frame structure for supporting the surrounding rock 4. Several connectors 2 are respectively disposed between two adjacent steel arch frame segments 1 for fixing the two adjacent steel arch frame segments 1; Several fasteners 3 are respectively installed in each steel arch frame segment 1 to fix the ring frame structure to the rock surface of the surrounding rock 4.

[0014] In the embodiments of this utility model, such as Figure 1and Figure 2 As shown, the dashed line represents the stratigraphic boundary line. During the initial support phase, the stratigraphic boundary line is determined by drawing the tunnel cross-section through geophysical exploration. Figure 1 The surrounding rock is classified as Class III or IV, 4. Figure 2 For Class IV and V surrounding rock 4, the ring frame structure used to support the surrounding rock 4 consists of several steel arch frame segments 1. During the prefabrication of the steel arch frame segments 1, they can be manufactured in batches according to different classes of surrounding rock 4, allowing for the use of steel arch frame segments 1 with different structures for different classes of surrounding rock 4. In low-strength surrounding rock 4 sections, steel arch frame segments 1 with larger cross-sections and stronger load-bearing capacity can be used, providing higher support strength and effectively suppressing deformation of the surrounding rock 4. In high-strength surrounding rock 4 sections, steel arch frame segments 1 with smaller cross-sections can be used, making full use of the surrounding rock 4. Its own stability and load-bearing capacity avoid unnecessary material waste and eliminate the problems of resource consumption and cost increase caused by excessive support. Through the prefabricated ring frame support structure, steel arch frame segments 1 with different cross sections and load-bearing capacities can be selected for surrounding rock 4 with different strength levels. At the same time, under the action of connectors 2, each steel arch frame segment 1 is fixedly connected to form a stable support structure. With the cooperation of fasteners 3, the formed ring frame structure can be fixed on the surrounding rock 4, ensuring the stability of the ring frame structure after installation.

[0015] At the boundary between different grades of surrounding rock 4, to ensure installation stability, the position of connector 2 should be within the range of high-strength surrounding rock 4. That is, the end of the steel arch segment 1 in the low-strength surrounding rock 4 area should extend into the high-strength surrounding rock 4 through the stratum boundary line. Simultaneously, due to the influence of different grades of surrounding rock 4, such as... Figure 1 and Figure 2 As shown, in Class III and IV surrounding rock 4, the steel arch frame segment 1 preferably uses 8 segments, while in Class IV and V surrounding rock 4, the steel arch frame segment 1 preferably uses 10 segments.

[0016] Based on the above scheme, connector 2 can be a clamp-like fastening structure. Preferably, the structure of connector 2 can be optimized, such as... Figure 3 and Figure 4 As shown, the connector 2 includes two steel plates 201, which are fixedly connected to the ends of two adjacent steel arch frame segments 1, and are also fixedly connected together. The steel plates 201 serve as the base for the connection, and are fixedly connected to the ends of two adjacent steel arch frame segments 1. When the two steel arch frame segments 1 are moved to the installation position, the two pre-welded steel plates 201 will face each other and come together, thus facilitating the fixed connection of the two steel arch frame segments 1. The fixed connection between the steel plates 201 and the steel arch frame segments 1 is by welding, and the two steel plates 201 can also be welded after butt joint.

[0017] However, in order to simplify the assembly steps of the steel arch frame segment 1, the connection method of the two steel plates 201 is optimized. Specifically, each of the two steel plates 201 is provided with at least one mounting hole 202, and a screw 203 is passed through the corresponding mounting hole 202. The screw 203 is threadedly connected to a nut 204.

[0018] During installation, the operator only needs to align the mounting holes 202 of the two steel plates 201, insert the screw 203, and then tighten the nut 204 to complete the connection. The operation is simple and requires little technical skill from the operator. It is suitable for the rapid assembly of steel arch frame segments 1 in tunnels with limited space and complex environments. Moreover, unlike the permanent connection formed by welding, the connection through the screw 203 is detachable. If contour errors are found during installation, the screw 203 can be loosened for fine adjustment and repositioning.

[0019] Moreover, the steel plate 201 is rectangular and has four mounting holes 202. The four mounting holes 202 are located at the corners of the steel plate 201. The four mounting holes 202 are arranged at the four corners of the rectangle. When the screw 203 is tightened, the force can be evenly transmitted through the entire contact surface of the steel plate 201, effectively resisting the bending moment, axial force and shear force that may occur at the connection of the steel arch frame segment 1, preventing the connection node from warping or rotating, and ensuring the rigid connection of the node.

[0020] Specifically, such as Figure 1 and Figure 2 As shown, the fixing component 3 is a locking anchor rod. The locking anchor rod passes through the steel arch frame segment 1 and is installed inside the surrounding rock 4. After the tunnel is excavated, the stress of the surrounding rock 4 is released, and the arch foot position bears huge vertical pressure and horizontal thrust. The locking anchor rod passes through the steel arch frame segment 1 and the shallow surrounding rock 4, transferring its anchoring force to the deep, undisturbed, stable rock mass, thereby improving the bearing capacity and safety of the entire support system.

[0021] Specifically, such as Figure 2 As shown, the support structure also includes a support frame 5, which is arranged radially along the surrounding rock 4 and supported between two opposing steel arch frame segments 1. The support frame 5 can be arranged at multiple angles radially along the surrounding rock 4 to cope with the most unfavorable loads from different directions. It is preferably supported between the top steel arch frame segment 1 and the bottom steel arch frame segment 1, which effectively improves the overall rigidity of the ring frame structure.

[0022] Meanwhile, the support frame 5 includes several support frame segments, which are connected end to end in sequence to form a complete support frame 5. This realizes the modular design of the support frame 5. Each support frame segment is lightweight and easy to transport, and is standardized and prefabricated in the factory to ensure processing quality.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A non-parameter initial support structure for ultra-large cross-section tunnels, installed in the surrounding rock (4), characterized in that, include: Several steel arch frame segments (1) are respectively set on the rock surface of the surrounding rock (4), and the several steel arch frame segments (1) are connected end to end in sequence to form a ring frame structure for supporting the surrounding rock (4). Different cross sections and bearing capacities of steel arch frame segments (1) are used for the surrounding rock (4) with different strength grades. A plurality of connectors (2) are respectively disposed between two adjacent steel arch frame segments (1) for fixing the two adjacent steel arch frame segments (1). Several fasteners (3) are respectively installed on each of the steel arch frame segments (1) to fix the ring frame structure to the rock surface of the surrounding rock (4).

2. The initial support structure for ultra-large cross-section tunnels with unequal parameters according to claim 1, characterized in that, The connector (2) includes two steel plates (201), which are fixedly connected to the ends of two adjacent steel arch frame segments (1) and are fixedly connected together.

3. The initial support structure for ultra-large cross-section tunnels with unequal parameters according to claim 2, characterized in that, Both steel plates (201) are provided with at least one mounting hole (202), and a screw (203) is provided between the mounting holes (202), and a nut (204) is threaded onto the screw (203).

4. The initial support structure for ultra-large cross-section tunnels with unequal parameters according to claim 3, characterized in that, The steel plate (201) is rectangular, and there are four mounting holes (202), which are located at the corners of the steel plate (201).

5. The initial support structure for ultra-large cross-section tunnels with unequal parameters according to claim 1, characterized in that, The fixing component (3) is a foot anchor rod, which passes through the steel arch frame segment (1) and is installed inside the surrounding rock (4).

6. The initial support structure for ultra-large cross-section tunnels with unequal parameters according to claim 1, characterized in that, The support structure also includes a support frame (5), which is arranged radially along the surrounding rock (4) and supported between two opposing steel arch frame segments (1).

7. The initial support structure for ultra-large cross-section tunnels with unequal parameters according to claim 6, characterized in that, The support frame (5) includes several support frame segments, which are connected end to end in sequence.

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