Bottom support for controlling deformation of surrounding rock of traffic tunnel and parameter determination method of bottom support

Abstract

The invention belongs to the technical field of surrounding rock supporting, and particularly discloses a bottom support for controlling traffic tunnel surrounding rock deformation and a parameter determination method thereof.The bottom support comprises a pier wall part connected with side wall surrounding rock of a traffic tunnel, the section of the pier wall part is in a right trapezoid shape, and the parameter determination method of the pier wall part comprises the steps that the height of the pier wall part is preset; the pressure borne by the side wall surrounding rock of the traffic tunnel is determined according to the height of the pier wall part and the cavern height of the traffic tunnel; according to the safety coefficient of the traffic tunnel and the pressure borne by the side wall surrounding rock of the traffic tunnel, shear force applied to the pier wall part by the side wall surrounding rock is determined; according to the height of the pier wall part and the shearing force, the upsetting moment applied to the pier wall part by the side wall surrounding rock is determined; and determining the upper bottom width and the lower bottom width of the pier wall part according to the shearing force and the overturning moment. According to the parameter determination method, the optimal size parameter of the pier wall part can be determined, so that the traffic tunnel can be stably supported, the influence of the bottom support on the use of the traffic tunnel can be avoided, and meanwhile, the construction cost can be saved.

Description

Technical Field

[0001] The invention belongs to the technical field of surrounding rock support, and discloses a soleplate for controlling the deformation of surrounding rock of a traffic tunnel and a method for determining its parameters. Background Art

[0002] When a penstock needs to be installed in the lower horizontal section of a water conveyance tunnel of a hydropower project, a temporary traffic tunnel perpendicular to the water conveyance tunnel will be excavated for transporting the penstock. Due to the large diameter of the traffic tunnel and being open on both sides, the unloading and relaxation of the surrounding rock are obvious, resulting in large deformations of the surrounding rock side walls and cracking of the shotcrete layer. Therefore, it is necessary to support the surrounding rock of the traffic tunnel.

[0003] Limited by construction conditions and excessive deformation of the surrounding rock, traditional support measures such as bolts, cables, anchor plates, and steel arch frames cannot be used in the traffic tunnel. Specifically: bolt, cable, and anchor plate supports are difficult to resist large deformations; the installation and fixation of steel arch frame supports have high requirements for technology, equipment, on-site space, and are difficult to construct with high costs. Summary of the Invention

[0004] The purpose of the invention is to provide a soleplate for controlling the deformation of surrounding rock of a traffic tunnel and a method for determining its parameters, so as to solve the technical problem that existing support measures are limited by construction conditions and excessive deformation of the surrounding rock and are difficult to be applied in the traffic tunnel.

[0005] The first aspect of the invention provides a method for determining the parameters of a soleplate for controlling the deformation of surrounding rock of a traffic tunnel. The soleplate includes a pier wall portion connected to the side wall surrounding rock of the traffic tunnel, and the cross-section of the pier wall portion is a right trapezoid. Then, the method for determining the parameters of the pier wall portion includes:

[0006] Step 1: Preset the height of the pier wall portion, and determine the pressure exerted on the side wall surrounding rock of the traffic tunnel according to the height of the pier wall portion and the chamber height of the traffic tunnel;

[0007] Step 2: Determine the shear force exerted by the side wall surrounding rock on the pier wall portion according to the safety factor of the traffic tunnel and the pressure exerted on the side wall surrounding rock of the traffic tunnel;

[0008] Step 3: Determine the overturning moment exerted by the side wall surrounding rock on the pier wall portion according to the height of the pier wall portion and the shear force;

[0009] Step 4: Determine the upper base width and the lower base width of the pier wall portion according to the shear force and the overturning moment.

[0010] Preferably, step 4 is specifically:

[0011] Step 4.1: Construct a first relationship between the shear force and the gravity of the corresponding concrete of the pier wall portion;

[0012] Step 4.2: Establish the second relationship between the overturning moment and the corresponding concrete gravity of the pier wall part;

[0013] Step 4.3: Determine the upper base width and the lower base width of the pier wall part according to the first relationship and the second relationship.

[0014] Preferably, step 4.1 is specifically as follows:

[0015] Determine the friction coefficient of the concrete corresponding to the pier wall part;

[0016] Establish the first relationship between the product of the concrete gravity and the friction coefficient and the shear force.

[0017] Preferably, the first relationship is:

[0018] The shear force is less than or equal to the product of the concrete gravity and the friction coefficient.

[0019] Preferably, step 4.2 is specifically as follows:

[0020] Determine the resistance moment according to the concrete gravity corresponding to the pier wall part;

[0021] Establish the second relationship between the overturning moment and the resistance moment.

[0022] Preferably, the second relationship is:

[0023] The overturning moment is less than or equal to the resistance moment.

[0024] Preferably, the ratio of the height of the pier wall part to the chamber height of the traffic tunnel is 1:5 - 6.

[0025] Preferably, step 2 is specifically as follows:

[0026] Determine the shear force exerted by the sidewall surrounding rock on the pier wall part according to the product of the safety factor of the traffic tunnel and the pressure on the sidewall surrounding rock of the traffic tunnel.

[0027] The second aspect of the present invention provides a base support for controlling the deformation of the surrounding rock of a traffic tunnel, including two support structures, and each support structure includes a connecting part and a pier wall part connected integrally;

[0028] The connecting part is arranged on the bottom surface of the traffic tunnel, one end of the connecting part is connected to the sidewall surrounding rock of the traffic tunnel, and the other end is connected to the connecting part of another support structure;

[0029] The cross-section of the pier wall part is a right trapezoid, and the upper base width and the lower base width of the pier wall part are determined according to the parameter determination method of the base support for controlling the deformation of the surrounding rock of the traffic tunnel; the lower base of the pier wall part is connected to the upper surface of the connecting part, and the right-angled side of the pier wall part is connected to the sidewall surrounding rock.

[0030] Preferably, it further includes a through anchor cable.

[0031] The through anchor cable is perpendicular to the axis of the traffic tunnel, and one end of the through anchor cable is connected to the pier wall part, and the other end penetrates through the side wall surrounding rock.

[0032] The soleplate for controlling the deformation of the surrounding rock of the traffic tunnel and its parameter determination method of the present invention have the following beneficial effects compared with the prior art:

[0033] The parameter determination method of the soleplate for controlling the deformation of the surrounding rock of the traffic tunnel of the present invention can determine the optimal dimension parameters of the pier wall part, so as to not only achieve stable support for the traffic tunnel, but also avoid the soleplate affecting the use of the traffic tunnel, and at the same time save construction costs. Among them, the connecting part of the soleplate can support the side wall surrounding rock of the traffic tunnel, ensure the stability of the bottom of the pier wall and reduce the height of the chamber; the upper pier wall part of the soleplate can limit the large deformation of the side wall surrounding rock; the through anchor cable can play the role of an anchor plate, and the effect of restricting the deformation of the side wall surrounding rock is more significant.

[0034] The parameter determination method of the soleplate for controlling the deformation of the surrounding rock of the traffic tunnel of the present invention has clear concepts and definite parameters, which is convenient for designers to use, plays a good guiding role, and ensures the safety of the project. Description of the Drawings

[0035] Figure 1 It is a schematic diagram of the use state of the traffic tunnel in the embodiment of the present invention.

[0036] Figure 2 It is a flowchart of the parameter determination method of the soleplate for controlling the deformation of the surrounding rock of the traffic tunnel in the embodiment of the present invention.

[0037] Figure 3 It is a schematic diagram of the overall structure of the soleplate in the embodiment of the present invention.

[0038] Figure 4 It is a schematic diagram of the structure of the pier wall part in the embodiment of the present invention.

[0039] In the figure: 1 is the main power house; 2 is the water conveyance tunnel; 3 is the traffic tunnel; 4 is the connecting part; 5 is the pier wall part; 6 is the side wall surrounding rock; 7 is the first through anchor cable; 8 is the second through anchor cable. Detailed Embodiment

[0040] In the following description, specific details such as specific system architectures and technologies are presented for purposes of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from obscuring the description of the present invention.

[0041] As Figure 1 shown, when a penstock needs to be installed in the lower horizontal section of the diversion tunnel 2 corresponding to the main powerhouse 1 of a hydropower project, a traffic tunnel 3 that vertically penetrates the diversion tunnel 2 is excavated for transporting the penstock. Due to the relatively large diameter of the traffic tunnel 3 and its intersection with multiple diversion tunnels 2, there is a situation where it is open on two sides, and the unloading and relaxation of the sidewall surrounding rock 6 are obvious, resulting in large deformations and shotcrete cracking on the sidewalls of the sidewall surrounding rock 6. Therefore, it is necessary to support the sidewall surrounding rock 6 of the traffic tunnel 3.

[0042] The first aspect of the embodiments of the present invention provides a method for determining the parameters of a bottom support for controlling the deformation of the surrounding rock of a traffic tunnel. As Figures 2 to 4 shown, the bottom support includes a pier wall portion 5 that is in contact with the sidewall surrounding rock 6 of the traffic tunnel 3. The cross-section of the pier wall portion 5 is a right trapezoid. Then, the method for determining the parameters of the pier wall portion 5 in the bottom support includes:

[0043] Step 1: Preset the height of the pier wall portion 5, and determine the pressure exerted on the sidewall surrounding rock 6 of the traffic tunnel 3 based on the height of the pier wall portion 5 and the chamber height of the traffic tunnel 3. Specifically, determine the pressure exerted on the sidewall surrounding rock 6 of the traffic tunnel 3 according to the following formula (1).

[0044] (1)

[0045] In the formula, is the unit weight of the rock of the sidewall surrounding rock 6; is the chamber height (excluding the thickness of the bottom backfill concrete) of the traffic tunnel 3, is the height of the pier wall portion 5.

[0046] Step 2: Determine the shear force exerted by the sidewall surrounding rock 6 on the pier wall portion 5 based on the safety factor of the traffic tunnel 3 and the pressure exerted on the sidewall surrounding rock 6 of the traffic tunnel 3.

[0047] Exemplarily, determine the shear force exerted by the sidewall surrounding rock 6 on the pier wall portion 5 according to the following formula (2).

[0048] (2)

[0049] Step 3. Determine the overturning moment exerted by the sidewall surrounding rock 6 on the pier wall part 5 according to the height and the shear force of the pier wall part 5. .

[0050] Exemplarily, the overturning moment exerted by the sidewall surrounding rock 6 on the pier wall part 5 is determined according to the following formula (3) .

[0051] (3)

[0052] Step 4. Determine the upper bottom width and the lower bottom width of the pier wall part 5 according to the shear force and the overturning moment .

[0053] The specific content of the above Step 4 is as follows:

[0054] Step 4.1. Construct the first relationship between the shear force and the concrete gravity corresponding to the pier wall part 5, specifically:

[0055] Step 4.1.1. Determine the friction coefficient , , of the concrete corresponding to the pier wall part 5, where

[0056] is the friction angle of the concrete corresponding to the pier wall part 5. Step 4.1.2. Construct the first relationship between the product of the concrete gravity and the friction coefficient and the shear force , where the first relationship is: the shear force is less than or equal to the product of the concrete gravity and the friction coefficient

[0057] (4)

[0058] The concrete gravity in the above formula (4) is as shown in formula (5).

[0059] (5)

[0060] In the formula, is the upper bottom width of the pier wall part 5; is the lower bottom width of the pier wall part 5; is the height of the pier wall portion 5; For concrete weight.

[0061] Step 4.2: Construct overturning moment Concrete gravity corresponding to pier wall 5 The second relationship is:

[0062] Step 4.2.1: According to the concrete gravity of pier wall 5 Determine the resisting moment , as shown in formula (6).

[0063] (6)

[0064] Step 4.2.2: Construct overturning moment and resistance torque The second relationship is: Less than or equal to the resistance moment , as shown in formula (7).

[0065] (7)

[0066] Step 4.3: Determine the upper base width of the pier wall portion 5 based on the first relationship and the second relationship and bottom width Specifically, the upper base width of the pier wall 5 is obtained by combining formula (4) and formula (7) and bottom width .

[0067] The height of the pier wall portion 5 in the embodiment of the present invention is The ratio of the height of the tunnel chamber to the traffic tunnel 3 is 1:5-6, for example, 1:5, 1:5.3, 1:5.5, 1:6, etc.

[0068] For example, the height of the tunnel chamber 3 is , rock mass , concrete weight , the friction angle of the concrete corresponding to the pier wall 5 , safety factor .

[0069] The embodiment of the present invention presets the height of the pier wall portion 5 , then the upper base width of the pier wall 5 is obtained by combining formula (4) and formula (7) and bottom width .

[0070] In the embodiment of the present invention, the above method for determining the parameters of the base support for controlling the deformation of the surrounding rock of the traffic tunnel can determine the optimal dimensional parameters of the pier wall part 5, so as to not only achieve stable support for the traffic tunnel 3, but also avoid the influence of the base support on the use of the traffic tunnel 3, and at the same time save construction costs.

[0071] The method for determining the parameters of the base support for controlling the deformation of the surrounding rock of the traffic tunnel in the present invention has clear concepts and definite parameters, which is convenient for designers to use, plays a very good guiding role, and ensures the safety of the project.

[0072] In the second aspect of the embodiment of the present invention, a base support for controlling the deformation of the surrounding rock of the traffic tunnel is provided, as Figure 3 and Figure 4 shown, including two support structures, each support structure including a connecting part 4 and a pier wall part 5 connected integrally; the integral connection method can be casting. The above connecting part 4 is arranged on the bottom surface of the traffic tunnel 3, one end of the connecting part 4 is connected to the side wall surrounding rock 6 of the traffic tunnel 3, and the other end is connected to the connecting part 4 of another support structure; the thickness of the connecting part 4 only needs to meet the shear load under the maximum design tonnage during the transportation of the traffic tunnel 3, and the present invention does not limit this here. The cross-section of the pier wall part 5 is a right trapezoid, and the upper base width and the lower base width of the pier wall part 5 are determined according to the above method for determining the parameters of the base support for controlling the deformation of the surrounding rock of the traffic tunnel 3; the lower base of the pier wall part 5 is connected to the upper surface of the connecting part 4, and the right-angled side of the pier wall part 5 is connected to the side wall surrounding rock 6.

[0073] In the embodiment of the present invention, in order to improve the stability of the surrounding rock at the intersection of the traffic tunnel 3 and the water diversion tunnel 2, a through anchor cable is also provided, denoted as the first through anchor cable 7; the first through anchor cable 7 is perpendicular to the axis of the traffic tunnel 3, and one end of the first through anchor cable 7 is connected to the pier wall part 5, and the other end passes through the side wall surrounding rock 6. Multiple first through anchor cables 7 can be used, and multiple first through anchor cables 7 are arranged in parallel. In the embodiment of the present invention, multiple parallel through anchor cables are also arranged between adjacent two water diversion tunnels 2, denoted as the second through anchor cables 8, and the second through anchor cables 8 are parallel to the axis of the traffic tunnel 3, so that the square surrounding rock area surrounded by the traffic tunnel 3, the water diversion tunnel 2 and the main power house 1 has a reticulated anchor cable to improve the stability of the surrounding rock.

[0074] The base support of the present invention adopts the method of constructing in two sequences on both sides, that is, first constructing one side support structure, and then constructing the other side support structure, so as to be able to well meet the traffic requirements under the condition of controlling the stability of the surrounding rock.

[0075] The connecting part 4 of the present invention can support the side wall surrounding rock 6 of the traffic tunnel 3, ensure the stability of the pier wall part 5 and reduce the height of the cavern (as a safety margin), and the upper pier wall part 5 can limit the large deformation of the side wall surrounding rock 6; the first through anchor cable 7 can play the role of an anchor plate, and the effect of restricting the deformation of the side wall surrounding rock 6 is more significant.

[0076] The above are only several embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the relevant art can make some changes or modifications within the scope of the technical solution of the present invention by using the disclosed technical content, which are equivalent to equivalent embodiments and all fall within the scope of the technical solution.

Claims

1. A method for determining parameters of a bottom support for controlling the deformation of surrounding rocks in a traffic tunnel, characterized in that The bottom support includes a pier wall part connected to the side wall surrounding rock of the traffic tunnel. The cross-section of the pier wall part is a right trapezoid. The method for determining the parameters of the pier wall part includes: Step 1: Preset the height of the pier wall part, and determine the pressure exerted on the side wall surrounding rock of the traffic tunnel according to the height of the pier wall part and the chamber height of the traffic tunnel. Step 2: Determine the shear force exerted by the side wall surrounding rock on the pier wall part according to the safety factor of the traffic tunnel and the pressure exerted on the side wall surrounding rock of the traffic tunnel. Step 3: Determine the overturning moment exerted by the side wall surrounding rock on the pier wall part according to the height of the pier wall part and the shear force. Step 4: Determine the upper base width and the lower base width of the pier wall part according to the shear force and the overturning moment.

2. The method for determining the parameters of the bottom support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 1, characterized in that Step 4 is specifically as follows: Step 4.1: Construct a first relationship between the shear force and the concrete gravity corresponding to the pier wall part. Step 4.2: Construct a second relationship between the overturning moment and the concrete gravity corresponding to the pier wall part. Step 4.3: Determine the upper base width and the lower base width of the pier wall part according to the first relationship and the second relationship.

3. The method for determining the parameters of the bottom support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 2, characterized in that Step 4.1 is specifically as follows: Determine the friction coefficient of the concrete corresponding to the pier wall part. Construct a first relationship between the product of the concrete gravity and the friction coefficient and the shear force.

4. The method for determining the parameters of the base support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 3, characterized in that, The first relationship is: The shear force is less than or equal to the product of the concrete gravity and the friction coefficient.

5. The method for determining the parameters of the bottom support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 2, characterized in that, Step 4.2 is specifically as follows: Determine the resistance moment according to the concrete gravity corresponding to the pier wall part. Construct a second relationship between the overturning moment and the resistance moment.

6. The method for determining the parameters of the base support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 5, characterized in that, The second relationship is: The overturning moment is less than or equal to the resistance moment.

7. The method for determining the parameters of the base support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 1, characterized in that The ratio of the height of the pier wall part to the chamber height of the traffic tunnel is 1:5 - 6.

8. The method for determining the parameters of the bottom support for controlling the deformation of the surrounding rock of a traffic tunnel according to claim 1, characterized in that, Step 2 is specifically as follows: Determine the shear force exerted by the side wall surrounding rock on the pier wall part according to the product of the safety factor of the traffic tunnel and the pressure exerted on the side wall surrounding rock of the traffic tunnel.

9. A bottom support for controlling the deformation of surrounding rock in a traffic tunnel, characterized in that, It includes two support structures, and each support structure includes a connecting part and a pier wall part connected integrally. The connecting part is arranged on the bottom surface of the traffic tunnel. One end of the connecting part is connected to the side wall surrounding rock of the traffic tunnel, and the other end is connected to the connecting part of another support structure. The cross-section of the pier wall part is a right trapezoid. The upper base width and the lower base width of the pier wall part are determined according to the method for determining the parameters of the bottom support for controlling the deformation of the surrounding rock of the traffic tunnel according to any one of claims 1 - 8. The lower base of the pier wall part is connected to the upper surface of the connecting part, and the right-angle side of the pier wall part is connected to the side wall surrounding rock.

10. The base support for controlling the deformation of surrounding rock in a traffic tunnel according to claim 9, characterized in that It further includes a through anchor cable. The through anchor cable is perpendicular to the axis of the traffic tunnel, and one end of the through anchor cable is connected to the pier wall part, and the other end passes through the side wall surrounding rock.

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