Shield end reinforcing structure

Abstract

The utility model discloses a shield end reinforcing method and a shield end reinforcing structure. The shield end reinforcing method is realized through surrounding environment investigation, enclosure construction, site leveling, cast-in-situ bored pile construction, front retaining wall and side retaining wall construction, plain concrete backfilling, shield tunneling and greening protection. Comprising a cast-in-situ bored pile, a front retaining wall, a side retaining wall and shield tunneling machine holes, the cast-in-situ bored pile is arranged below the front retaining wall, the two shield tunneling machine holes are formed in the front retaining wall, and the center line of a shield tunnel left line of the shield tunneling machine hole on the left side is parallel to the center line of a shield tunnel right line of the shield tunneling machine hole on the right side; the shield tunneling machine hole in the left side and the shield tunneling machine hole in the right side are located in the same horizontal plane, and plain concrete is backfilled in the front retaining wall and the side retaining walls. The shield end reinforcing structure has small influence on the built underground tunnel, reduces the tunnel entering risk of the shield tunnel in the shallow-buried unsymmetrical-pressure section, reduces interference and damage to a mountain, and avoids water and soil loss caused by construction in the flood season, so that the safety requirement is met, and safe tunnel entering of the shield tunneling machine is achieved.

Description

Technical Field

[0001] The utility model relates to the field of tunnel construction, in particular to a shield end reinforcement structure. Background Art

[0002] With the development of more and more underground tunnel space, we have to face the situation of implementing shield tunnels under complex conditions such as adjacent to existing underground tunnels (including railway tunnels, subway tunnels, urban underground tunnels, etc.), mountain bias, partial leakage, and poor surrounding rock grade at the entrance. Due to the high protection requirements of the adjacent existing underground tunnel structure, it is difficult to enter the shield tunnel with mountain bias and partial leakage, and the construction risk of shield tunnel at the entrance section with poor surrounding rock grade is high, which poses a great challenge to the implementation of shield tunnels.

[0003] Based on the above situation, the utility model proposes a shield end reinforcement method and structure to effectively solve the above problems. Utility Model Content

[0004] In order to solve the problems existing in the background technology, the utility model provides a shield end reinforcement structure.

[0005] The utility model adopts the following technical solutions:

[0006] A shield end reinforcement structure comprises bored cast-in-place piles, a front retaining wall, a side retaining wall and a shield machine hole, wherein bored cast-in-place piles are arranged below the front retaining wall, and two shield machine holes are arranged in the front retaining wall, and the center line of the left line of the shield tunnel of the left shield machine hole is arranged parallel to the center line of the right line of the shield tunnel of the right shield machine hole, and the shield machine hole on the left is the same size as the shield machine hole on the right and is on the same horizontal plane, and the front retaining wall and the side retaining wall are backfilled with plain concrete.

[0007] Furthermore, the side retaining wall is a sloped surface.

[0008] Furthermore, a steel mesh is provided 45 mm away from the upper top surface of the plain concrete.

[0009] Furthermore, the field line between the front retaining wall and the bored piles is formed by the leveled ground.

[0010] Furthermore, a railway tunnel is provided under the ground line on one side of the front retaining wall.

[0011] Furthermore, the outer edges of the shield machines of the two shield machine holes are at the same horizontal height.

[0012] Furthermore, the front retaining wall and the side retaining wall are cast as an integrated structure.

[0013] A shield end reinforcement structure is realized by the following method, comprising the following steps:

[0014] Step 1: Investigation of surrounding environment: engineering geological data, existing structures and surrounding environment. Existing structures refer to data of existing railway tunnels nearby; data include bearing capacity limit, normal use limit, durability, etc.

[0015] Step 2: Construction enclosure and site leveling: After the surrounding environment survey is completed, construction enclosure is built, and vegetation and loose soil on the ground inside the enclosure are removed. After clearing the surface, mechanical compaction and site leveling are carried out; site line 1 is the ground surface after the surface is cleaned and leveled.

[0016] Step three: construct bored cast-in-place piles. The spacing and length of bored cast-in-place piles can be comprehensively determined based on the actual situation of the stratum and the requirements for the bearing capacity of the foundation. The comprehensive values ​​include the bearing capacity (including instability) calculation values ​​of structural components, fatigue verification values ​​of components that directly bear repeated loads, seismic bearing capacity calculation values ​​when there are seismic fortification requirements, and overturning, sliding, and floating verification values ​​of necessary structures.

[0017] For permanent design conditions, transient design conditions and seismic design conditions, when expressed in terms of forces, the ultimate limit state expressions for structural members shall be:

[0018] γ0S≤R

[0019] R=R(f c ,f s ,a k , ...) / γ Rd

[0020] Where: r0 is the structural importance coefficient: in the permanent design condition and the transient design condition, for the structural components with the safety level of level 1, it should not be less than 1.1; for the structural components with the safety level of level 2, it should not be less than 1.0; for the structural components with the safety level of level 3, it should not be less than 0.9; for the earthquake design condition, it should be 1.0;

[0021] S is the design value of the effect of the action combination under the ultimate bearing capacity state: for the permanent design condition and the transient design condition, it should be calculated according to the basic combination of actions; for the seismic design condition, it should be calculated according to the seismic combination of actions;

[0022] R is the design value of the resistance of the structural member;

[0023] R(■) is the resistance function of the structural member;

[0024] rRd is the uncertainty coefficient of the resistance model of the structural component: it is 1.0 for static design, and a value greater than 1.0 is taken according to the specific situation for structural components with greater uncertainty; the seismic adjustment coefficient of bearing capacity rRE is used instead of rRd for seismic design;

[0025] fc and fs are the design strength values ​​of concrete and steel bars;

[0026] ak is the standard value of the geometric parameter. When the variability of the geometric parameter has a significant adverse effect on the structural performance, an additional value should be added or subtracted.

[0027] Step 4: Construct the front retaining wall and the side retaining wall: after the bored pile construction is completed and tested to meet the requirements, excavate the foundation of the front retaining wall and the side retaining wall to form a temporary slope, and then cast the front retaining wall and the side retaining wall; the front retaining wall and the side retaining wall are cast as a whole at the same time, and the front retaining wall and the side retaining wall fall on a stable foundation; if the bearing capacity cannot meet the requirements, the foundation needs to be treated; the bearing capacity requirements must comply with the Code for Design of Concrete Structures GB 50010-2010.

[0028] Step 5. Plain concrete backfill: After the retaining wall reaches a certain strength, the front retaining wall and the inner side of the side retaining wall are backfilled with plain concrete to make it dense; a layer of steel mesh is set 45mm on the top surface of the plain concrete backfill reinforcement body. The specifications and spacing of the steel bars used can be determined according to the actual situation on site.

[0029] Step 6: Shield tunneling: After the strength of the plain concrete backfill is reached, the shield tunneling begins to advance and the lining segments are installed;

[0030] Step 7: Greening protection: The top of the plain concrete backfill reinforcement is backfilled with planting soil and greening protection is carried out to make the greening coordinated with the surrounding natural environment.

[0031] Furthermore, the existing railway tunnel data includes the railway tunnel location, structural dimensions, burial depth, and existing deformation data.

[0032] Furthermore, the surrounding environment refers to the topography, existing pipelines, and existing buildings and structures around the proposed site for the shield tunnel.

[0033] The utility model provides a shield end reinforcement method and structure: with little impact on existing underground tunnels, the risk of shield tunneling in shallow buried biased areas is reduced, while interference and damage to the mountain can be reduced, and soil erosion caused by construction during the flood season can be avoided, so that the permanent deformation of the existing underground tunnel caused by the implementation of the shield tunnel meets safety requirements, and the shield machine can enter the tunnel safely. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0035] Figure 2 It is a schematic diagram of the front retaining wall elevation of the utility model.

[0036] Figure 3 It is a cross-sectional schematic diagram of the utility model.

[0037] The serial numbers marked in the figure are as follows: 1-yard line, 2-bored cast-in-place piles, 3-front retaining wall, 4-side retaining wall, 5-plain concrete, 6-center line of left line of shield tunnel, 7-center line of right line of shield tunnel, 8-center line of railway tunnel, 9-ground line, 10-railway tunnel, 11-shield machine hole, 12-outer edge line of shield machine. DETAILED DESCRIPTION

[0038] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] Refer to the attached Figure 1-3 , a shield end reinforcement method, comprising the following steps:

[0040] Step 1: Investigation of surrounding environment: clarify the engineering geology, existing structures and surrounding environment. Existing structures refer to the existing railway tunnels nearby, including the location, structural dimensions, burial depth and existing deformation of the railway tunnels. The surrounding environment refers to the topography around the proposed shield tunnel site, existing pipelines (if any) and existing buildings (if any).

[0041] Step 2: Construction enclosure and site leveling: After the surrounding environment survey is completed, construction enclosure is built, and vegetation and loose soil on the ground inside the enclosure are removed. After clearing the surface, mechanical compaction and site leveling are carried out; site line 1 is the ground surface after the surface is cleaned and leveled.

[0042] Step three: construct bored cast-in-place piles 2. The spacing and pile length of the bored cast-in-place piles 2 can be comprehensively determined based on the actual situation of the stratum and the requirements for the foundation bearing capacity.

[0043] Step 4, construct the front retaining wall 3 and the side retaining wall 4: after the construction of the bored piles 2 is completed and tested to meet the requirements, the foundations of the front retaining wall 3 and the side retaining wall 4 are excavated to form a temporary slope, and then the front retaining wall 3 and the side retaining wall 4 are cast; the front retaining wall 3 and the side retaining wall 4 are cast as a whole at the same time. The front retaining wall 3 and the side retaining wall 4 should fall on a stable foundation. If the bearing capacity cannot meet the requirements, the foundation needs to be treated.

[0044] Step 5: Backfill with plain concrete 5: After the retaining wall strength reaches the requirement, backfill the front retaining wall 3 and the inner side of the side retaining wall 4 with plain concrete 5 to make it dense. A layer of steel mesh is set 45mm above the top surface of the backfilled reinforced concrete 5. The specifications and spacing of the steel bars used can be determined according to the actual situation on site.

[0045] Step 6: Shield tunneling: After the strength of the plain concrete 5 backfill reinforcement reaches the required level, the shield tunneling begins to advance and the lining segments are installed;

[0046] Step 7: Greening protection: The top of the plain concrete 5 is backfilled with planting soil and greened for protection, so that the greening is coordinated with the surrounding natural environment.

[0047] A shield end reinforcement structure includes bored cast-in-place piles 2, a front retaining wall 3, a side retaining wall 4 and a shield machine hole 11, wherein bored cast-in-place piles 2 are arranged below the front retaining wall 3, and two shield machine holes 11 are arranged in the front retaining wall 3. The shield machine holes 11 include two, and the left line center line 6 of the shield tunnel of the left shield machine hole 11 is parallel to the right line center line 7 of the shield tunnel of the right shield machine hole 11, and the left shield machine hole 11 is the same size as the right shield machine hole 11 and is on the same horizontal plane, and the front retaining wall 3 and the side retaining wall 4 are backfilled with plain concrete 5.

[0048] The side retaining wall 4 is a slope surface.

[0049] A steel mesh is provided 45 mm away from the upper top surface of the plain concrete 5 .

[0050] The area between the front retaining wall 3 and the bored piles 11 is a field line formed by the leveled ground.

[0051] A railway tunnel 10 is arranged under the ground line on one side of the front retaining wall 3. In the figure, reference numeral 8 is the center line of the railway tunnel, which is used to show the center position of the railway tunnel.

[0052] The outer edges 12 of the two shield machine holes 11 are at the same level.

[0053] The front retaining wall 3 and the side retaining wall 4 are cast as an integrated structure.

[0054] Bored pile is a common deep foundation construction method. It forms pile holes through mechanical drilling, and then pours concrete in the holes (usually placing steel cages first) to form the pile body. Use drilling machinery to drill holes of a certain diameter in the ground. After these holes reach the designed depth, they are used to place steel cages and pour concrete. Construction steps: The positioning drill must be horizontal and stable, ensuring that the overhead crane, turntable, and pile core are in a plumb line; reasonably design the drill bit, add a guard ring on the upper part to make the drill bit rotate smoothly; set a guide device on the active drill rod to prevent excessive shaking; check the verticality of the drill rod frequently.

[0055] Lining segments are precast concrete components used for tunnel lining. They play an important role in tunnel construction. Lining segments are mainly used in underground projects such as tunnels, subways, water conservancy channels, etc. to prevent surrounding rock deformation or collapse. They are installed along the perimeter of the tunnel body to form a permanent support structure. Lining segments are usually prefabricated in factories or construction sites, and then transported to the tunnel construction site for assembly. According to different materials and manufacturing processes, they can be divided into metal segments, reinforced concrete segments and other types.

[0056] The site line refers to the relatively flat ground elevation line formed after excavation and filling. The site line is determined during site leveling. Site leveling refers to the transformation of the original ground into a plane that meets the needs of construction, production, and life by excavating high and filling low. This process involves the calculation of earthwork volume and earthwork balance adjustment.

[0057] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A shield end reinforcement structure, characterized in that: It includes bored cast-in-place piles, a front retaining wall, a side retaining wall and a shield machine hole. Bored cast-in-place piles are arranged under the front retaining wall. Two shield machine holes are arranged in the front retaining wall. The center line of the left line of the shield tunnel of the left shield machine hole is parallel to the center line of the right line of the shield tunnel of the right shield machine hole. The shield machine hole on the left is the same size as the shield machine hole on the right and is on the same horizontal plane. The front retaining wall and the side retaining wall are backfilled with plain concrete, and the side retaining wall is a slope surface.

2. A shield end reinforcement structure according to claim 1, characterized in that: A steel mesh is provided 45 mm from the upper surface of the plain concrete.

3. A shield end reinforcement structure according to claim 1, characterized in that: The area between the front retaining wall and the bored cast-in-place piles is a field line formed by the leveled ground.

4. A shield end reinforcement structure according to claim 1, characterized in that: A railway tunnel is arranged under the ground line on one side of the front retaining wall.

5. The shield end reinforcement structure according to claim 1, characterized in that: The outer edges of the two shield machine holes are at the same horizontal height.

6. A shield end reinforcement structure according to claim 1, characterized in that: The front retaining wall and the side retaining wall are cast as an integrated structure.

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