Shallow-buried collapsible loess tunnel supporting structure

Abstract

The utility model provides a shallow-buried collapsible loess tunnel supporting structure, and belongs to the technical research field of tunnel engineering. In order to overcome the defects in the prior art, the steel supports are additionally arranged, the steel supports are installed below the steel arch frame, and then the inclined piles are embedded into the steel supports; thus, when pressure transmitted by surrounding rock of a tunnel hole wall acts on the steel supports through the steel arch, load borne by the steel supports is shared by the inclined piles, the capacity of the tunnel for bearing the pressure of the surrounding rock is improved, and the structure of the inclined piles and the steel arch can greatly reduce shearing force and bending moment caused by transverse load pressure of the tunnel soil wall, so that the bearing capacity of the tunnel is improved. The vertical load pressure borne by the vault can be reduced through the inclined piles, and the vault is effectively prevented from sinking.

Description

Technical Field

[0001] The utility model belongs to the research field of tunnel engineering technology, and specifically relates to a shallow buried collapsible loess tunnel support structure. Background Art

[0002] With the acceleration of urbanization, underground space development has become the focus of urban development. Tunnel construction has become an important underground project to meet the development needs of transportation in western my country. However, the western region is mostly loess, and the construction of mountain tunnels and underground subway projects in loess areas faces challenges. During the excavation of shallow collapsible loess tunnels, the soil at the top of the tunnel will settle under the action of its own weight. If the settlement is serious, the force on the tunnel rock will be too concentrated. During the excavation of shallow collapsible loess tunnels, the tunnel often collapses due to stress concentration, leading to safety accidents, which is not conducive to the smooth progress of loess tunnel excavation. The existing initial tunnel support structure cannot control tunnel deformation well. Therefore, it is of great significance to study how to ensure the stability of collapsible loess at the top of shallow tunnels.

[0003] The patent with publication number CN115628077A discloses a reinforcement support structure for a collapsible loess tunnel, including: a steel mesh fitted with the tunnel soil wall, and a steel arch frame is provided on the other side of the steel mesh, a plurality of anchor rods are interspersed on the steel arch frame and the steel mesh, one end of the anchor rod is inserted into the tunnel soil wall, the other end of the anchor rod is threadedly connected with a fixing bolt, and the fixing bolt abuts against the side of the steel arch frame away from the steel mesh, a plurality of support frames are also provided between the steel arch frame and the steel mesh, the support frame includes a first support rod and a second support rod, one end of the first support rod and the second support rod are both abutted against the steel mesh, the other ends of the first support rod and the second support rod are both abutted against the steel arch frame, and the first support rod and the second support rod are arranged inclined relative to each other. When in use, the support frame can further enhance the supporting stability of the supporting structure. When the steel arch frame is fixed by fixing bolts and anchor rods, the support frame can also be fixed between the steel arch frame and the steel mesh. The first support rod and the second support rod are arranged obliquely to each other, forming a stable structure of an approximate triangle between the steel mesh and the steel arch frame, thereby enhancing the tightening effect between the steel arch frame and the steel mesh to reduce the phenomenon of the arch top sinking. Among them, the first plug hole and the second plug hole are provided on the anchor rod to connect the anchor rod to the support frame.

[0004] However, in the above technical solution, the support frame is hinged by the first support rod and the second support rod, and the two are fixed between the anchor rods by a fixing mechanism arranged at both ends of the third support rod; in actual use, the supporting force of the hinged part of the first support rod and the second support rod is poor. First, due to the limitation of the distance between the anchor rods, the lengths of the first support rod and the second support rod are relatively short, and the first support rod and the second support rod are hinged, and the supporting force of the hinged part of the two is poor. In the case of the vault sinking, the hinged part of the first support rod and the second support rod cannot effectively support the steel mesh, that is, it cannot withstand the pressure at different positions of the tunnel; second: the fixing effect of the first fixing mechanism and the second fixing mechanism respectively arranged at both ends of the third support rod is poor. In actual use, when the support frame is subjected to the pressure of the vault sinking, the gear in the first fixing mechanism is very easy to be damaged under the condition of excessive force, thereby causing the first support rod to be displaced, and the support frame loses its supporting function. Utility Model Content

[0005] The purpose of the utility model is to overcome the problems of the prior art. The technical idea adopted by the utility model is: to add steel supports and install the steel supports under the steel arch frame, and then embed the inclined piles into the steel supports; in this way, the pressure from the surrounding rock of the tunnel wall acts on the steel supports through the steel arch frame, and the load borne by the steel supports is shared by the inclined piles, so as to improve the ability of the tunnel to withstand the surrounding rock pressure. The structure of the inclined piles and the steel arch frame can greatly reduce the shear force and bending moment caused by the lateral load pressure of the tunnel soil wall, and at the same time, the vertical load pressure borne by the arch can be reduced through the inclined piles, thereby effectively preventing the arch from sinking.

[0006] Based on the above technical ideas, the technical solution adopted by the utility model is:

[0007] A shallow buried collapsible loess tunnel support structure, comprising a steel arch frame, and further comprising:

[0008] Steel support, including: inclined pile limiting holes and steel arch connection holes;

[0009] The steel support is connected to the steel arch frame through the steel arch frame connecting hole, and is connected to the inclined pile through the inclined pile limiting hole.

[0010] To further limit the above technical solution, preferably, the steel support is a square structure.

[0011] As a further limitation of the above technical solution, the inclined pile limiting hole is an inclined elliptical through hole.

[0012] A further limitation of the above technical solution is that the steel support is arranged in a steel support groove and is connected to the frame foot of the steel arch frame.

[0013] A further limitation of the above technical solution further includes a fixed frame structure; the fixed frame structure includes the fixed frame structure including a crossbeam;

[0014] Through holes are respectively provided at both ends of the crossbeam for fixing inclined piles.

[0015] The fixed frame structure in the above technical solution further includes a longitudinal connecting beam;

[0016] The longitudinal connecting beam is connected to the transverse beam.

[0017] Beneficial effects of the utility model:

[0018] The utility model increases steel supports and installs the steel supports under the steel arch frame, and then embeds the inclined piles into the steel supports; in this way, the pressure from the surrounding rock of the tunnel wall acts on the steel supports through the steel arch frame, and the load borne by the steel supports is shared by the inclined piles, so as to improve the tunnel's ability to withstand the surrounding rock pressure. The structure of the inclined piles and the steel arch frame can greatly reduce the shear force and bending moment caused by the lateral load pressure of the tunnel soil wall, and at the same time, the vertical load pressure borne by the arch crown can be reduced through the inclined piles, thereby effectively preventing the arch crown from sinking.

[0019] The utility model combines inclined piles with the traditional support system. Compared with vertical piles, vertical piles are difficult to directly offset the larger horizontal loads and vertical loads on the steel supports. However, under the same load, inclined piles can withstand a larger axial force than vertical piles, that is, the single pile bearing capacity of inclined piles is greater than that of vertical piles. The use of inclined piles can reduce the shear force and bending moment caused by lateral loads, and can effectively solve the deformation and instability problem of shallow buried collapsible loess.

[0020] The steel support provided by the utility model has a simple structure, is easy to manufacture and install, and can be applied to various tunnel projects.

[0021] Moreover, in practical applications, a plurality of inclined piles can be arranged along the tunnel direction, and the plurality of inclined piles are respectively connected to the steel arch frame through steel supports, so that the ability of the inclined piles to withstand the surrounding rock pressure can be further improved.

[0022] The utility model also provides a fixed frame structure, which includes a crossbeam and a longitudinal connecting beam, the crossbeam and the longitudinal connecting beam are connected and arranged perpendicular to each other; when in use, through holes are respectively provided at both ends of the crossbeam, so that the inclined piles can be connected to the crossbeam through the through holes;

[0023] In actual use, multiple inclined piles are arranged in the direction of the tunnel, one end of each of the inclined piles is fixed on the steel support, and the other end passes through the through hole and is fixed by the crossbeam. In this way, both ends of each inclined pile are respectively fixed by the steel support and the fixed frame structure, ensuring the horizontal and vertical connection between the multiple inclined piles, while improving the stability of the inclined piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a schematic diagram of the structure of a shallow buried collapsible loess tunnel support structure proposed by the utility model;

[0026] Figure 2 It is a schematic diagram of the structure of the reinforcement anchor;

[0027] Figure 3 This is a structural diagram of the steel support.

[0028] Figure 4 It is a top view of the surface frame;

[0029] Among them, 1. lining; 2. waterproof layer; 3. steel arch frame; 31. reserved hole; 4. steel support; 41. inclined pile limit hole; 42. steel arch frame connection hole; 5. inclined pile; 6. reinforcement anchor rod; 61. grouting port; 62. sealing plug; 7. fixing screw; 8. mud drill bit; 9. cross beam; 10. longitudinal connecting beam. DETAILED DESCRIPTION

[0030] In the description of the present invention, it should be understood that the terms "length direction", "upper", "lower", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present utility model clearer, the technical solution in the embodiments of the present utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the present utility model.

[0033] Example 1

[0034] like Figure 1 As shown, a shallow buried collapsible loess tunnel support structure provided by the utility model includes a steel arch frame 3, a steel support 4, an inclined pile 5 and an anchor rod 6.

[0035] In actual implementation, at the foot position of the steel arch frame 3, steel support grooves are excavated outward on both sides of the tunnel bottom, so that two steel supports 4 can be installed respectively under the feet on both sides of the steel arch frame 3 to fix the inclined piles 5.

[0036] The steel support 4 is a square structure, including inclined pile limiting holes 41 and steel arch connection holes 42 .

[0037] The inclined pile limiting hole 41 is an inclined elliptical through hole.

[0038] It should be noted that the embodiment of the utility model does not limit the inclination angle of the inclined pile limiting hole 41. The embodiment of the utility model is described by taking the inclination angle of the inclined elliptical through hole 41 in the vertical direction as 15° as an example.

[0039] In actual use, two inclined piles 5 are driven into the tunnel soil from the ground through the inclined pile limiting holes 41 at an angle of about 15° from the vertical direction with the tunnel as the center. The two inclined piles 5 form a group. In actual application, multiple steel arch frames 3 can be set, and each steel arch frame 3 is combined with a group of inclined piles, so that the pressure from the surrounding rock of the tunnel wall can be greatly increased.

[0040] The steel arch connection hole 42 is a threaded hole so as to be threadedly connected to the steel arch 3 .

[0041] In actual use, the steel arch frame 3 is arranged along the tunnel, and the fixing screws 7 penetrate the steel arch frame 3 and are connected to the steel arch frame connecting holes 42 , so that the steel arch frame 3 is fixedly arranged on the steel support 4 .

[0042] The steel arch frame 3 is provided with a plurality of reserved holes which are arranged at equal intervals, so that a plurality of reinforcing anchor rods 6 can pass through, so that the plurality of reinforcing anchor rods 6 are arranged at equal intervals on the steel arch frame 3 .

[0043] The reinforcement anchor rod 6 is a grouting anchor rod with a central cavity; specifically, a mud drill bit 8 is provided at the front end of the reinforcement anchor rod 6, and a grouting port 61 is provided at the end thereof, and a sealing plug 62 is provided on the grouting port 61. When in use, mud is injected into the central cavity of the anchor rod 6 from the grouting port 61, and after the mud is filled, the mud filled inside the anchor rod 6 is sealed by the sealing plug 62.

[0044] A waterproof layer 2 is arranged on the inner side of the lower end of the steel arch frame 3 , and a lining 1 is laid on the inner side of the lower end of the waterproof layer 2 .

[0045] Specifically, the waterproof layer 2 is made of cement mortar and is arranged inside the steel arch 3 .

[0046] The lining 1 is a sprayed concrete layer applied on the inner side of the water stop piles of the waterproof layer 2.

[0047] Example 2

[0048] Based on the above embodiment, different from the above embodiment 1, the shallow buried collapsible loess tunnel support structure provided by the embodiment of the utility model further includes a fixed frame structure, wherein the fixed frame structure includes a cross beam 9 and a longitudinal connecting beam 10 .

[0049] The crossbeam 9 is used to fix the inclined piles 5. In practical applications, a through hole is respectively provided at both ends of the crossbeam 9 to fix the ends of a group of inclined piles.

[0050] The longitudinal connecting beam 10 is connected to the transverse beam 9 so as to connect each group of inclined piles, thereby ensuring the transverse and longitudinal connection between each inclined pile and improving the stability of the inclined pile 5.

[0051] Implementation Cases:

[0052] Step 1: Use the double side wall pilot method to excavate the tunnel, and after excavating the two side walls of the tunnel, excavate the steel support grooves on both sides of the tunnel bottom outwards;

[0053] Step 2: embed the two steel supports 4 into the steel support notches on both sides of the tunnel bottom, pour reinforced concrete at the upper end of the tunnel, complete the pouring of the cross beam 9 and the longitudinal connecting beam 10, and at the same time drive the inclined piles 5 from the ground surface so that the inclined piles 5 pass through the inclined pile limit holes 41 and are driven into the tunnel soil;

[0054] Step 3: excavate the remaining part of the tunnel, then construct the steel arch frame 3, set the steel arch frame 3 along the prefabricated tunnel and fix it on the steel support 4 by fixing screws 7;

[0055] Step 4: construct a waterproof layer 2 along the steel arch frame 3, and then construct a lining 1 along the water stop piles.

[0056] Step 5: Finally, the reinforcement anchor rod 6 is driven into the surrounding rock through the lining 1, the waterproof layer 2 and the steel arch frame 3, and then the anchor rod 6 is grouted through the grouting hole 61. After the grouting hole 61 is filled, it is sealed through the sealing plug 62.

[0057] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A shallow buried collapsible loess tunnel support structure, comprising a steel arch frame (3), characterized in that: Also includes: The steel support (4) comprises: an inclined pile limiting hole (41) and a steel arch connection hole (42); The steel support (4) is connected to the steel arch frame (3) through the steel arch frame connection hole (42), and is connected to the inclined pile (5) through the inclined pile limit hole (41).

2. A shallow buried collapsible loess tunnel support structure according to claim 1, characterized in that: The steel support (4) is a square structure.

3. A shallow buried collapsible loess tunnel support structure according to claim 2, characterized in that: The inclined pile limiting hole (41) is an inclined elliptical through hole.

4. A shallow buried collapsible loess tunnel support structure according to claim 3, characterized in that: The steel support (4) is arranged in a steel support notch and is connected to a support foot of the steel arch frame (3).

5. The shallow buried collapsible loess tunnel support structure according to claim 1 is characterized in that: Also includes: A fixed frame structure; the fixed frame structure comprises a crossbeam (9); Through holes are respectively provided at both ends of the crossbeam (9) for fixing the inclined piles (5).

6. A shallow buried collapsible loess tunnel support structure according to claim 1, characterized in that: The fixed frame structure also includes a longitudinal connecting beam (10); The longitudinal connecting beam (10) is connected to the cross beam (9).

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