Positioning fixture for expanding arch springing in excavation of weak surrounding rock tunnel of high-speed railway

Abstract

The utility model discloses a positioning fixture for expanding an arch foot in excavation of a weak surrounding rock tunnel of a high-speed railway, which comprises an upper chord, a lower chord, a left web member and a right web member which are combined into a trapezoidal truss structure, and the left web member and the right web member are respectively connected to the left side and the right side of the upper chord and the lower chord; the upper chord is of an arc structure with the same radius as the inner contour of the primary support, and the length of the upper chord is equal to the distance from the end point of the line side of the expanded arch springing and the end point of the surrounding rock side of the expanded arch springing to the intersection point of the tangent point of the outer contour of the primary support and the inner contour of the primary support corresponding to the radial direction of the circle center. The lower chord is of a linear structure, and the length of the lower chord is the tangent length from the side end point of the surrounding rock of the expanded arch springing to the outer contour of the primary support; the length of the left web member is the same as the width of the expanded arch foot; and the length of the right web member is the same as the vertical length of the lower chord member and the thickness of the primary support. According to the utility model, the loss caused by irregular expansion of the expansion arch feet is reduced, the potential safety hazard is reduced, and the energy-saving and environment-friendly effects are obvious.

Description

Technical Field

[0001] The utility model relates to the technical field of high-speed railway tunnel construction, and more specifically to a positioning fixture for excavating and expanding an arch foot in a high-speed railway tunnel with soft surrounding rock. Background Art

[0002] During the excavation of soft rock tunnels, there are no special tools to locate the clearance dimensions of the cross-section contour at the arch foot. In the past, mechanical and manual excavation processes used rulers and the workers' proficiency to connect the excavation contours. This resulted in problems such as difficulty in controlling over-excavation and under-excavation, time-consuming and labor-intensive adjustments, inconsistent protective layer sizes, large errors, and severe overconsumption.

[0003] Therefore, when excavating tunnels in soft surrounding rocks, it is urgent to solve the problems of what kind of special device to use to control and position the clearance size of the inner contour of the excavated and expanded arch foot to avoid excessive over-excavation and under-excavation, uneven protective layer size, large errors and serious over-consumption, and slow work efficiency. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a positioning fixture for excavating and expanding the arch foot of a high-speed railway soft surrounding rock tunnel, so as to judge the under-excavation position and improve the excavation accuracy and construction quality.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0006] A positioning fixture for excavating and expanding an arch foot in a soft surrounding rock tunnel for a high-speed railway comprises an upper chord, a lower chord, a left web and a right web assembled into a trapezoidal truss structure, wherein the left web and the right web are respectively connected to the left and right sides of the upper chord and the lower chord; the upper chord is an arc structure with the same radius as the inner contour of an initial support, and the length of the upper chord is the distance between the tangent point between the end point on the line side of the expanded arch foot and the end point on the surrounding rock side of the expanded arch foot and the outer contour of the initial support and the intersection point of the inner contour of the initial support corresponding to the radial direction of the center of the circle; the lower chord is a straight structure, and the length of the lower chord is the length of the tangent line between the end point on the surrounding rock side of the expanded arch foot and the outer contour of the initial support; the length of the left web is the same as the width of the expanded arch foot; the length of the right web is the same as the vertical length of the lower chord and the thickness of the initial support.

[0007] To further optimize the technical solution, a plurality of vertical rods are provided between the upper chord and the lower chord to enhance stability.

[0008] To further optimize the technical solution, diagonal bars are provided between adjacent vertical bars between the upper chord bar and the lower chord bar.

[0009] To further optimize the technical solution, the vertical rod and the lower chord rod are arranged perpendicularly, and the angle between the diagonal rod and the vertical rod is 45°.

[0010] To further optimize the technical solution, the upper chord, lower chord, left web, right web, vertical rods and diagonal rods are all welded with Ф20 steel bars.

[0011] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is as follows.

[0012] The utility model provides a positioning fixture for excavating and expanding the arch foot in a high-speed railway tunnel with soft surrounding rock. The fixture is simple to manufacture and easy to operate. The under-excavation position is judged by the positioning fixture, and the excavation quality and the loss of sprayed concrete caused by over-excavation and under-excavation are effectively controlled. The loss caused by irregular expansion of the expanded arch foot is reduced, the safety hazard is reduced, and the energy-saving and environmental protection effects are remarkable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural diagram of the utility model;

[0014] Figure 2 This is a schematic diagram of the corresponding positions of the inner and outer contours of the initial support at the expanded arch foot of the utility model;

[0015] Figure 3 This is a schematic diagram of on-site measurement and positioning of the utility model.

[0016] Among them: 1. Upper chord, 2. Lower chord, 3. Left web, 4. Right web, 5. Vertical rod, 6. Diagonal rod, 7. Expanded arch foot, 8. Initial support outer contour, 9. Initial support inner contour, 10. Center of circle, 11. Tangent point, 12. Staff, 13. Surrounding rock. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] A positioning fixture for excavating and expanding the arch foot in soft rock tunnels of high-speed railways, combined with Figures 1 to 2 As shown, it includes an upper chord 1, a lower chord 2, a left web 3 and a right web 4. The upper chord 1, the lower chord 2, the left web 3 and the right web 4 are combined into an irregular trapezoidal truss structure, and the left web 3 and the right web 4 are connected to the left and right sides of the upper chord 1 and the lower chord 2 respectively.

[0019] The upper chord 1 is an arc structure with the same radius as the initial support inner contour 9. The length of the upper chord 1 is the distance between the end point on the line side of the expanded arch foot 7 and the end point on the surrounding rock 13 side of the expanded arch foot 7 to the intersection of the tangent point 11 of the initial support outer contour 8 and the initial support inner contour 9 corresponding to the radial direction of the center 10 of the circle.

[0020] The lower chord 2 is a straight structure, and the length of the lower chord 2 is the tangent length from the end point of the surrounding rock 13 of the expanded arch foot 7 to the initial support outer contour 8.

[0021] The length of the left web member 3 is the same as the width of the expanded arch foot 7, and the length of the right web member 4 is the same as the vertical length of the lower chord 2 and the initial support thickness.

[0022] Several vertical rods 5 are arranged between the upper chord rod 1 and the lower chord rod 2, and diagonal rods 6 are arranged between adjacent vertical rods 5. The vertical rods 5 are arranged perpendicular to the lower chord rod 2, and the angle between the diagonal rod 6 and the vertical rod 5 is 45°. By arranging the vertical rods 5 and the diagonal rods 6 between the upper chord rod 1 and the lower chord rod 2, the stability of the positioning fixture is improved.

[0023] The upper chord 1, the lower chord 2, the left web 3, the right web 4, the vertical rod 5 and the diagonal rod 6 are all welded with Ф20 steel bars.

[0024] The schematic diagram of on-site measurement and positioning of the utility model is as follows Figure 3 As shown, when the worker 12 is working on site, he holds a positioning fixture with the upper chord of the positioning fixture facing the line side, and inserts it into the excavation section of the expanded arch foot for measurement and positioning, so as to determine the under-excavation position and make adjustments, so as to effectively control the excavation quality and the loss of sprayed concrete caused by over-excavation and under-excavation.

Claims

1. A positioning fixture for excavating and enlarging the arch foot in soft rock tunnels for high-speed railways, characterized by: The invention comprises an upper chord (1), a lower chord (2), a left web (3) and a right web (4) which are combined into a trapezoidal truss structure, wherein the left web (3) and the right web (4) are respectively connected to the left and right sides of the upper chord (1) and the lower chord (2); the upper chord (1) is an arc structure with the same radius as the inner contour (9) of the initial support, and the length of the upper chord (1) is from the end point on the line side of the expanded arch foot (7) and the end point on the surrounding rock (13) side of the expanded arch foot (7) to the outer wheel of the initial support. The distance between the tangent point (11) of the profile (8) and the intersection point of the initial support inner profile (9) corresponding to the radial direction of the circle center (10); the lower chord (2) is a straight structure, and the length of the lower chord (2) is the tangent length from the side end point of the expanded arch foot surrounding rock (13) to the initial support outer profile (8); the length of the left web (3) is the same as the width of the expanded arch foot (7); the length of the right web (4) is the same as the vertical length of the lower chord (2) and the initial support thickness.

2. The positioning fixture for excavating and expanding the arch foot of a high-speed railway tunnel with soft surrounding rock according to claim 1 is characterized by: A plurality of vertical rods (5) for enhancing stability are provided between the upper chord (1) and the lower chord (2).

3. The positioning fixture for excavating and expanding the arch foot of a high-speed railway tunnel with soft surrounding rock according to claim 2 is characterized by: Diagonal bars (6) are provided between adjacent vertical bars (5) between the upper chord bar (1) and the lower chord bar (2).

4. The positioning fixture for excavating and expanding the arch foot of a high-speed railway tunnel with soft surrounding rock according to claim 2, characterized in that: The vertical rod (5) and the lower chord rod (2) are arranged vertically, and the angle between the diagonal rod (6) and the vertical rod (5) is 45 degrees.

5. The positioning fixture for excavating and enlarging the arch foot of a high-speed railway tunnel with soft surrounding rock according to claim 3, characterized in that: The upper chord (1), the lower chord (2), the left web (3), the right web (4), the vertical rod (5) and the diagonal rod (6) are all welded with Ф20 steel bars.

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