Shield arch protection structure for shallow buried stratum

Abstract

The utility model relates to a shield arch protection structure for a shallow buried stratum. A traditional shield top anti-floating structure usually adopts a flat plate form, and the adverse effect of backfilling and pressing in the later period on a shield is not considered, so that the structure is relatively single. The device comprises an arch ring, a plurality of bearing platforms and a plurality of pile foundations, the pile foundations are vertically arranged at intervals and symmetrically arranged on the two sides of a shield, and the root of each pile foundation is provided with an expanded end which is used for balancing the buoyancy effect of underground water on the shield; the bearing platforms are transversely arranged on the tops of the pile foundations correspondingly, the bottom ends of the arch rings are arranged on the upper end faces of the bearing platforms correspondingly, and the arch rings are used for bearing later-period planned filling loads. The anti-floating and load-bearing composite board has the anti-floating and load-bearing functions, and overcomes the unicity of the prior art.

Description

Technical Field

[0001] The utility model relates to the technical field of shield construction, in particular to a shield arch protection structure used in shallow buried strata. Background Art

[0002] Today, infrastructure construction has entered a peak period. According to statistics, 96% of subway sections across the country are constructed using the shield method. Water conservancy, hydropower, municipal pipelines and other projects also use shield construction. After more than 20 years of experience accumulation, shield machines are adaptable to a wide range of strata.

[0003] However, when the shield is excavating in composite strata or hard rock strata, the buoyancy of the shield segments is greater than their own weight. Therefore, the segments that have been grouting and have not yet solidified and have just separated from the shield tail will often float partially or as a whole, which manifests as segment misalignment, cracks, breakage, and even axis deviation. This will cause quality defects such as vertical segment floating and horizontal displacement of the formed tunnel axis exceeding the limit. Severe exceeding the limit will also have a certain adverse impact on the later operation.

[0004] At present, due to factors such as topography, connection conditions, and construction safety, the line selection sets the shield section through the shallow buried stratum section, which will cause the risk of roof collapse during the construction period, structural floating and backfill pressure during the operation period. The traditional shield top anti-floating structure often adopts a flat plate form, and does not consider the adverse effects of backfill pressure on the shield in the later stage, and the structure is relatively simple.

[0005] Therefore, there is an urgent need for a shield arch structure that can have both anti-floating and load-bearing functions. Summary of the invention

[0006] The utility model aims to provide a shield arch protection structure for shallow buried strata, so as to at least solve the problem of single structure in the prior art.

[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0008] A shield arch structure for shallow buried strata, comprising an arch ring, a plurality of caps and a plurality of pile foundations, wherein the plurality of pile foundations are vertically spaced and symmetrically arranged on both sides of the shield, and the roots of the pile foundations are provided with enlarged ends for balancing the buoyancy of groundwater on the shield;

[0009] The caps are laterally arranged on the tops of the plurality of pile foundations, and the bottom ends of the arch rings are arranged on the upper end surfaces of the caps. The arch rings are used to bear the backfill loads planned in the later stage.

[0010] Furthermore, the top of the pile foundation must be roughened and leveled, and a concrete cushion layer must be laid.

[0011] Furthermore, the trench core must be backfilled before the shield passes through the shallow trench core.

[0012] Furthermore, the distance between the backfill line of the trench core backfill during the construction period and the top surface of the shield is not less than 1.5 times the diameter of the shield.

[0013] Furthermore, there are at least two supporting platforms.

[0014] Furthermore, joint steel bars are reserved on the upper end surface of the foundation.

[0015] Furthermore, the upper end surface of the pedestal is connected to the bottom end of the arch ring by casting.

[0016] Furthermore, the area below the arch foot outside the arch ring is backfilled with mortar-laid stone slabs.

[0017] Furthermore, the area above the outer arch foot of the arch ring is backfilled with plain soil to the planned line.

[0018] Furthermore, after the arch ring is cast and reaches the designed strength, the gap above the backfill line during the construction period and below the arch portion of the arch ring is backfilled and compacted with the plain soil.

[0019] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0020] 1. The utility model adopts a concrete arch protection structure with an arch ring, a cap and a pile foundation integrated from top to bottom. The force bearing and transmission mechanism is clear, the load distribution is reasonable, and it has both anti-floating and load-bearing functions, overcoming the singleness of the existing technology.

[0021] 2. The utility model can not only bear the backfill soil pressure load generated by the development needs in the later stage through the upper arch ring, and reduce the additional load effect of the backfill soil on the shield; it can also overcome the floating effect of groundwater on the shield during the operation period through the enlarged end of the lower pile foundation, thereby achieving anti-pullout effect. At the same time, the utility model can be quickly poured and constructed on site, the construction is easy, and the overall rigidity, strength and durability are strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, drawings of other embodiments can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of the utility model installed around the shield;

[0024] Figure 2 yes Figure 1 Left view of;

[0025] Figure 3 yes Figure 1 A top view of

[0026] The symbols in the figure are:

[0027] 1-arch ring, 2-capping platform, 3-pile foundation, 4-shield, 5-plain soil, 6-mortared stone, 7-concrete cushion. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the relevant drawings. The drawings provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0029] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Example:

[0032] like Figure 1-3 As shown, a shield arch structure for shallow buried strata has clear force and force transmission mechanisms, reasonable load distribution, and dual functions of anti-floating and load-bearing. It is easy to cast on site and has strong overall stiffness, strength and durability. The structure includes an arch ring 1, two pedestals 2 and a plurality of pile foundations 3. The plurality of pile foundations 3 are vertically equidistantly spaced and symmetrically arranged on both sides of the shield 4. The roots of the pile foundations 3 adopt an enlarged end form to balance the buoyancy of groundwater on the shield 4, thereby achieving anti-pullout effect.

[0033] The two caps 2 are transversely arranged on the top of a plurality of pile foundations 3, and the bottom ends of the arch rings 1 are arranged on the upper end surfaces of the caps 2. The arch rings 1 are used to bear the fill load planned in the later stage.

[0034] Furthermore, before setting the cap 2, the top of the pile foundation 3 must be roughened and leveled, and a concrete cushion layer 7 must be laid.

[0035] Before the shield 4 passes through the shallow buried trench core, the trench core must be backfilled, and the distance between the backfill line and the top surface of the shield 4 during the construction period should not be less than 1.5 times the diameter of the shield 4.

[0036] in, Figure 1 The straight line crossing the arch ring 1 is the backfill line during the construction period.

[0037] The arch ring 1 and the base 2 are both made of concrete.

[0038] A joint steel bar is reserved on the upper end surface of the pedestal 2, and the upper end surface of the pedestal 2 is connected to the bottom end of the arch ring 1 by casting the joint steel bar.

[0039] Furthermore, the area below the outer arch foot of the arch ring 1 is backfilled with mortar-laid stone 6, and the area above the outer arch foot of the arch ring 1 is backfilled with plain soil 5 to the planned line.

[0040] After the arch ring 1 is poured and reaches the designed strength, the gap above the backfill line during the construction period and below the arch part of the arch ring 1 is backfilled densely with plain soil 5 without leaving any gaps.

[0041] When groundwater rises or backfill soil is heavily loaded, the arch structure of this embodiment and the shield 4 can transfer and conduct pressure through the plain soil 5 buffer layer to avoid structural damage caused by rigid contact between the arch structure of this embodiment and the shield 4.

[0042] The installation process of this embodiment is as follows:

[0043] After the construction of shield section 4 is completed, pile foundation 3 is constructed from bottom to top;

[0044] After the pile foundation 3 reaches the designed strength, the top is roughened and leveled, and a concrete cushion layer 7 is laid. After the laying is completed, the cap 2 is constructed, and the joint steel bars are reserved on the top surface of the cap 2;

[0045] The bottom end of the arch ring 1 is connected to the top surface of the cap 2 by pouring the joint steel bars;

[0046] After the arch ring 1 is poured and reaches the designed strength, the gap above the backfill line during the construction period and below the arch portion of the arch ring 1 is backfilled with plain soil 5 to be dense without leaving any gaps;

[0047] Finally, mortar-laid stone slabs 6 are used to backfill below the arch foot outside the arch ring 1, and plain soil 5 is used to backfill above the arch foot to the planned line.

[0048] The above specific examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. For those skilled in the art of the present invention, some simple deductions, deformations or substitutions can be made based on the idea of ​​the present invention.

Claims

1. A shield arch structure for shallow buried strata, characterized in that: The structure comprises an arch ring (1), a plurality of caps (2) and a plurality of pile foundations (3), wherein the plurality of pile foundations (3) are vertically spaced and symmetrically arranged on both sides of a shield (4), and the roots of the pile foundations (3) are provided with enlarged ends for balancing the buoyancy effect of groundwater on the shield (4); The caps (2) are transversely arranged on the tops of the plurality of pile foundations (3), the bottom ends of the arch rings (1) are arranged on the upper end surfaces of the caps (2), and the arch rings (1) are used to bear the fill load planned in the later stage.

2. The shield arch structure for shallow buried strata according to claim 1, characterized in that: The top of the pile foundation (3) must be roughened and leveled, and a concrete cushion layer (7) must be laid.

3. The shield arch structure for shallow buried strata according to claim 1, characterized in that: The trench core must be backfilled before the shield (4) passes through the shallow buried trench core.

4. The shield arch structure for shallow buried strata according to claim 3 is characterized by: The distance between the backfill line during the construction period of the trench core backfill and the top surface of the shield (4) is not less than 1.5 times the diameter of the shield (4).

5. The shield arch structure for shallow buried strata according to claim 1, characterized in that: There are at least two supporting platforms (2).

6. The shield arch structure for shallow buried strata according to claim 1, characterized in that: A joint steel bar is reserved on the upper end surface of the cap (2).

7. The shield arch structure for shallow buried strata according to claim 1, characterized in that: The upper end surface of the pedestal (2) is cast in connection with the bottom end of the arch ring (1).

8. The shield arch structure for shallow buried strata according to claim 1, characterized in that: The arch ring (1) is backfilled below the outer arch foot with mortar-laid stone slabs (6).

9. The shield arch structure for shallow buried strata according to claim 4, characterized in that: Plain soil (5) is used to backfill above the outer arch foot of the arch ring (1) to the planned line.

10. The shield arch structure for shallow buried strata according to claim 9, characterized in that: After the arch ring (1) is poured and reaches the designed strength, the gap above the backfill line during the construction period and below the arch portion of the arch ring (1) is backfilled and compacted with the plain soil (5).

Images