Drainage structure for tunnel portal of gully intersection shallow-buried bias

Abstract

The utility model provides a kind of shallow-buried bias pressure tunnel portal drainage structure of gully intersection, including mountain, gully structure, bias pressure tunnel and drainage structure, bias pressure tunnel includes open cut section and blind hole section, gully structure includes backfill part and gully part, drainage structure is set in the upstream end of gully part to separate the upstream end of gully part into first drainage ditch and second drainage ditch, and one end of drainage structure is stopped in the downstream end of first drainage ditch, and first drainage ditch is communicated with outside roadbed side ditch by pre-buried pipeline. Thus, through the bias pressure tunnel structure of half open and half dark cooperates gully backfill system, the instability and base hollowing risk of conventional bias pressure retaining wall scheme are avoided, the risk of surrounding rock collapse during tunnel excavation construction is reduced;And the upstream end of gully part is separated into the form of blind ditch and open ditch partition by drainage structure, solve the drainage problem of gully tunnel portal construction period and operation period, and the drainage system can cope with different drainage needs in dry season and wet season.

Description

Technical Field

[0001] This utility model relates to the field of drainage technology for biased tunnels, and in particular to a drainage structure for the entrance of a shallow-buried biased tunnel at the confluence of gullies. Background Technology

[0002] Water damage accidents in tunnels often occur at the intersection of the tunnel entrance and the gully. The flow of water from the gully poses a significant safety risk to the safety of the tunnel structure and the drainage at the entrance.

[0003] For long-distance, shallow-buried tunnels with eccentric pressure located near gullies, the current conventional practice is to install an eccentric retaining wall on the side of the tunnel closest to the gully to address the uneven stress on the tunnel structure caused by topographic eccentricity, thereby preventing shear failure. Simultaneously, counter-pressure backfilling is carried out in the shallow-buried section to reduce the risk of tunnel collapse during excavation. However, this approach has several problems:

[0004] 1. The bearing capacity of the foundation of the eccentric retaining wall is poor, and foundation reinforcement is generally required, which increases the number of procedures and costs of the project; 2. The turbulent flow of the gully carries gravel, which increases the risk of instability of the eccentric retaining wall. At the same time, the turbulent flow can also cause the foundation of the retaining wall to be hollowed out; 3. The backfilling and excavation of long-distance shallow buried eccentric sections increases the risk of collapse during construction and leakage during operation.

[0005] Therefore, it is necessary to propose a drainage structure for the shallow buried biased tunnel entrance at the confluence of gullies to solve or at least alleviate the above-mentioned defects. Utility Model Content

[0006] The main purpose of this utility model is to provide a drainage structure for shallow buried biased tunnel entrances at gully confluences, so as to solve the problem of poor bearing capacity of existing drainage structures for gully tunnel entrances.

[0007] To achieve the above objectives, this utility model provides a drainage structure for a shallow-buried, biased-pressure tunnel entrance at a gully confluence, comprising a mountain, a gully structure, a biased-pressure tunnel, and a drainage structure, wherein the mountain has gullies; wherein,

[0008] The biased tunnel includes an open section and a closed section, and the gully structure includes a backfill section and a gully section; wherein...

[0009] The gully grooves of the mountain and the outside of the tunnel section are both filled with backfill. The gully groove is recessed at the top of the backfill. The upstream end of the gully groove is curved. The drainage structure is set in the upstream end of the gully groove to divide the upstream end of the gully groove into a first drainage ditch and a second drainage ditch that are spaced apart laterally. One end of the drainage structure stops at the downstream end of the first drainage ditch. The first drainage ditch is connected to the roadbed ditch outside the tunnel through a pre-buried pipe. The downstream end of the second drainage ditch is connected to the downstream end of the gully groove.

[0010] Preferably, the drainage structure includes a partition wall and a retaining wall. The partition wall is connected to the upstream end of the gully to divide the upstream end of the gully into the first drainage ditch and the second drainage ditch. The retaining wall is fixed to the end side of the partition wall to block the downstream end of the first drainage ditch.

[0011] Preferably, the first drainage ditch has a drain hole extending vertically, and the bottom end of the drain hole is connected to the pre-buried pipe.

[0012] Preferably, the depth of the first drainage ditch is greater than the depth of the second drainage ditch, and the width of the first drainage ditch is less than the width of the second drainage ditch.

[0013] Preferably, it also includes a corrugated steel plate that extends circumferentially along the open section to connect to the outer side of the open section.

[0014] Preferably, the device further includes a plurality of I-beams spaced apart along the longitudinal direction, the I-beams extending circumferentially along the dark cavity section to connect and be disposed on the outside of the dark cavity section, and one end of the I-beams being connected to the corrugated steel plate.

[0015] Preferably, it also includes a plurality of pipe sheds, which are arranged longitudinally and are spaced apart around the I-beam along the circumferential direction of the dark hole section.

[0016] Preferably, the upper surface of the backfill section is provided with a clay waterproof layer.

[0017] Preferably, the clay waterproof layer has a slope that is inclined toward the gully portion.

[0018] Preferably, the pre-embedded pipe is an HDPE pipe.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This utility model provides a drainage structure for a shallow-buried biased tunnel entrance at a gully confluence, comprising a mountain, a gully structure, a biased tunnel, and a drainage structure. The mountain has gullies, and the biased tunnel includes an open section and a closed section. The gully structure includes a backfill section and a gully section. The gullies and open sections of the mountain are filled with backfill. The gully section is recessed at the top of the backfill section, and the upstream end of the gully section is curved. The drainage structure is located in the upstream end of the gully section to divide the upstream end of the gully section into a first drainage ditch and a second drainage ditch arranged laterally. One end of the drainage structure is stopped at the downstream end of the first drainage ditch. The first drainage ditch is connected to the roadbed ditch outside the tunnel through a pre-buried pipe, and the downstream end of the second drainage ditch is connected to the downstream end of the gully section. By eliminating the conventional eccentric retaining wall, and using a semi-open, semi-closed eccentric tunnel structure in conjunction with a gully backfilling system, the risks of instability and foundation erosion associated with conventional eccentric retaining wall schemes are avoided. This also reduces the risk of rockfall during tunnel excavation and the risk of tunnel lining cracking and leakage during operation. Furthermore, by dividing the upstream end of the gully section into open and closed drainage sections, the drainage problem at the tunnel entrance during construction and operation is solved. This drainage system can meet the different drainage needs during dry and wet seasons without affecting the safety and use of the tunnel. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a schematic elevation view of the overall structure in one embodiment of the present utility model;

[0023] Figure 2 This is a plan view of the overall structure in one embodiment of the present utility model;

[0024] Figure 3 This is a schematic diagram illustrating the application scenarios of this utility model during drainage in dry and wet seasons.

[0025] The purpose, features, and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0026] Explanation of icon numbers:

[0027] 10. Mountain; 20. Gully structure; 210. Backfill section; 220. Gully section; 221. First drainage ditch; 2211. Embedded pipe; 2212. Drainage hole; 222. Second drainage ditch; 30. Biased tunnel; 310. Open tunnel section; 311. Corrugated steel plate; 320. Closed tunnel section; 321. I-beam; 322. Pipe shed; 40. Drainage structure; 410. Separation wall; 420. Water retaining wall. Detailed Implementation

[0028] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0031] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0032] Please see the appendix Figure 1-3 This utility model provides an embodiment of a drainage structure 40 for a shallow-buried biased tunnel entrance at a gully confluence, comprising a mountain 10, a gully structure 20, a biased tunnel 30, and a drainage structure 40. The mountain 10 has gully channels. First, it should be noted that in this application, "longitudinal" refers to the extension direction of the biased tunnel 30, and "transverse" refers to the width direction of the biased tunnel 30. The specific design is as follows:

[0033] The biased tunnel 30 includes an open section 310 and a closed section 320. The gully structure 20 includes a backfill section 210 and a gully section 220. The gully groove of the mountain 10 and the outside of the open section 310 are filled with the backfill section 210. The gully section 220 is recessed at the top of the backfill section 210. The upstream end of the gully section 220 is curved. The drainage structure 40 is set in the upstream end of the gully section 220 to divide the upstream end of the gully section 220 into a first drainage ditch 221 and a second drainage ditch 222 arranged laterally. One end of the drainage structure 40 is stopped at the downstream end of the first drainage ditch 221. The first drainage ditch 221 is connected to the roadbed ditch outside the tunnel through a pre-buried pipe 2211. The downstream end of the second drainage ditch 222 is connected to the downstream end of the gully section 220.

[0034] Specifically, the drainage structure 40 at the shallow buried biased tunnel entrance at the confluence of gullies in this application includes a mountain 10, a gully structure 20, a biased tunnel 30, and a drainage structure 40. This application is mainly applied to the entrance of a long-distance shallow buried biased tunnel at the confluence of gullies. Therefore, the mountain 10 where it is located has a gully groove for constructing the gully structure 20. Under the biased terrain conditions, the risk of rock collapse during excavation increases, and the tunnel lining structure is subjected to uneven stress with severe asymmetry in load on the left and right sides, which can easily cause cracking and leakage in the tunnel lining. In severe cases, it can cause shear failure of the tunnel structure. Therefore, the biased tunnel 30 adopts a semi-open and semi-closed structure, including an open section 310 and a closed section 320. This reduces the slope height, which is beneficial to construction safety and effectively reduces the risk of collapse during tunnel construction due to shallow overburden. Mechanical excavation is used to avoid the disturbance of the surrounding rock caused by traditional blasting excavation, reduce construction risks, and minimize the impact on the surrounding environment.

[0035] The gully structure 20 includes a backfill section 210 and a gully section 220. The backfill section 210 is the backfill soil used for the outer side of the tunnel section 310 after excavation and construction, as well as the gully channel. Backfilling can reduce tunnel bias pressure. The backfill soil can be used from the tunnel excavation. During backfilling, the gully section 220 is reserved to serve as a drainage system. When constructing the gully section 220, a bend is formed at the upstream end of the gully section 220 to create a curved shape. The drainage structure 40 is located at this curved section of the gully section 220. For details, please refer to the appendix. Figure 2Under the separation effect of the drainage structure 40, a first drainage ditch 221 and a second drainage ditch 222 are formed. The first drainage ditch 221 is the concave bank side away from the biased tunnel 30, and the second drainage ditch 222 is the convex bank side close to the biased tunnel 30. It is worth mentioning that one end of the drainage structure 40 also extends laterally to block the downstream end of the first drainage ditch 221. Thus, the water flowing into the first drainage ditch 221 is blocked in the first drainage ditch 221. The water is discharged by connecting the pre-buried pipe 2211 inside the first drainage ditch 221 with the roadbed ditch outside the tunnel, which forms a culvert drainage scheme. The water flowing into the second drainage ditch 222 flows directly to the downstream end of the gully section 220 and is finally diverted to the external ditch. This forms a combination of culvert and open ditch. The setting of the culvert reduces the size of the open ditch, reduces permanent land use, and is conducive to ecological restoration.

[0036] In a preferred embodiment of the present invention, the drainage structure 40 includes a partition wall 410 and a water-retaining wall 420. The partition wall 410 is connected to the upstream end of the gully section 220 to divide the upstream end of the gully section 220 into the first drainage ditch 221 and the second drainage ditch 222. The water-retaining wall 420 is fixed to the end side of the partition wall 410 to block the downstream end of the first drainage ditch 221.

[0037] It should be noted that the partition wall 410 is used to separate the first drainage ditch 221 and the second drainage ditch 222 which are arranged laterally, and the water retaining wall 420 is used to block the downstream end of the first drainage ditch 221 to limit the flow direction of water in the first drainage ditch 221, so as to facilitate the flow out through the pre-buried pipe 2211.

[0038] In a preferred embodiment of the present invention, a drain hole 2212 extending vertically is provided in the first drainage ditch 221, and the bottom end of the drain hole 2212 is connected to the pre-embedded pipe 2211.

[0039] It should be noted that a drain hole 2212 is provided to facilitate the diversion of water to the pre-embedded pipe 2211, and then discharge it through the pre-embedded pipe 2211. The pre-embedded pipe 2211 can be made of HDPE pipe, which has strong flow capacity and good flexibility, good resistance to deformation and impact, and is easy to install and transport. It is worth mentioning that the pre-embedded pipe is encased in C20 concrete, and the pre-embedded pipe 2211 can also solve the drainage problem during construction.

[0040] In a preferred embodiment of the present invention, the depth of the first drainage ditch 221 is greater than the depth of the second drainage ditch 222, and the width of the first drainage ditch 221 is less than the width of the second drainage ditch 222.

[0041] It is worth noting that by forming a structure in which the first drainage ditch 221 is deep and narrow, and the second drainage ditch 222 is shallow and wide, this application achieves the separation of surface water and sediment water through the setting of bends and partition walls 410. Influenced by factors such as centrifugal force, the water flow creates scouring on the outside of the bend, while sediment accumulates on the inside. Therefore, most of the sediment water flows through the shallow and wide second drainage ditch 222, while most of the surface water flows through the deep and narrow first drainage ditch 221. This significantly reduces the impact of surface water flow. The probability of blockage of the pre-buried pipe 2211 is reduced; and a large amount of water is discharged through the pre-buried pipe 2211, which reduces the scouring of the concrete structure by the torrent. Since the inner side of the bend is located near the tunnel, the inner ditch is wide and shallow, and the flow velocity is slow. The silt and sand on the inner shallow beach can prevent the torrent from scouring the tunnel cover soil, which plays a protective role and reduces the impact of the torrent on the drainage ditch structure and the tunnel structure. The setting of the open ditch (second drainage ditch 222) can also solve the problem of the surge in drainage volume during the high water season and prevent impurities from clogging the drainage pipe.

[0042] Furthermore, it also includes a corrugated steel plate 311, which extends circumferentially along the open section 310 to connect to the outer side of the open section 310.

[0043] It should be noted that when excavating the open tunnel section 310, the slope ratio is 1:0.3, and corrugated steel plate 311 is installed as a protective arch. Corrugated steel plate 311 (especially in the open tunnel section 310) can effectively adapt to the construction environment and functional requirements of the open tunnel due to its material properties and structural advantages. A single 8mm thick 400cm*150cm corrugated steel plate 311 is used, and its total longitudinal length is compatible with the excavation cycle length of the closed tunnel.

[0044] Furthermore, it also includes a plurality of I-beams 321 arranged longitudinally at intervals, the I-beams 321 extending circumferentially along the dark cavity section 320 to connect and be disposed on the outside of the dark cavity section 320, and one end of the I-beams 321 being connected to the corrugated steel plate 311.

[0045] It should be understood that the 321 I-beam support is a common form of initial support. It is a steel arch support system that is set at intervals. I20 321 I-beams can be used, with a longitudinal spacing of 50cm. One end is connected to the corrugated steel plate 311 of the open tunnel section 310, and the other end rests on the tunnel arch foot. After the inner side is reinforced with steel mesh, a layer of C20 concrete is sprayed on top to form the initial support of the tunnel.

[0046] Furthermore, it also includes multiple pipe sheds 322, which are arranged longitudinally and are spaced apart around the I-beam 321 along the circumferential direction of the dark hole section 320.

[0047] It should be noted that the pipe roof 322 is used as an advanced support measure. Usually, the pipe roof 322 is constructed first, and then the tunnel section is constructed. The Φ108 pipe roof 322 is used, and the end of the pipe roof 322 is connected to a double-layer advanced small guide pipe. This is a technology well known to those skilled in the art, so it will not be described in detail here. The secondary lining can be made of 60cm thick C40 reinforced concrete. The above data are applied to the embodiments of this application. Those skilled in the art can also set the specific dimensions according to the actual situation.

[0048] Furthermore, a clay waterproofing layer is provided on the upper surface of the backfill section 210.

[0049] It should be noted that the clay waterproof layer is used to prevent surface water from seeping into the ground, and it can be set to be 50cm thick.

[0050] Furthermore, the clay waterproof layer has a slope that is inclined toward the gully portion 220.

[0051] It is understandable that a slope is formed to facilitate the introduction of surface water into the drainage system of the gully section 220 for drainage. Preferably, a longitudinal slope of 2% and a transverse slope of 1:10 can be formed. Specific parameters can be selected by those skilled in the art according to actual needs.

[0052] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A drainage structure for the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies, characterized in that, This includes a mountain, gully structures, a biased tunnel, and drainage structures; the mountain has gullies. The biased tunnel includes an open section and a closed section, and the gully structure includes a backfill section and a gully section; wherein... The gully grooves of the mountain and the outside of the tunnel section are both filled with backfill. The gully groove is recessed at the top of the backfill. The upstream end of the gully groove is curved. The drainage structure is set in the upstream end of the gully groove to divide the upstream end of the gully groove into a first drainage ditch and a second drainage ditch that are spaced apart laterally. One end of the drainage structure stops at the downstream end of the first drainage ditch. The first drainage ditch is connected to the roadbed ditch outside the tunnel through a pre-buried pipe. The downstream end of the second drainage ditch is connected to the downstream end of the gully groove.

2. The drainage structure at the shallow-buried, biased tunnel entrance at the confluence of gullies according to claim 1, characterized in that, The drainage structure includes a partition wall and a retaining wall. The partition wall is connected to the upstream end of the gully to divide the upstream end of the gully into the first drainage ditch and the second drainage ditch. The retaining wall is fixed to the end side of the partition wall to block the downstream end of the first drainage ditch.

3. The drainage structure at the shallow-buried, biased tunnel entrance at the confluence of gullies according to claim 2, characterized in that, The first drainage ditch has a vertically extending drainage hole, and the bottom end of the drainage hole is connected to the pre-buried pipe.

4. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 2, characterized in that, The depth of the first drainage ditch is greater than the depth of the second drainage ditch, and the width of the first drainage ditch is less than the width of the second drainage ditch.

5. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 1, characterized in that, It also includes a corrugated steel plate that extends circumferentially along the open section to connect to the outside of the open section.

6. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 5, characterized in that, It also includes multiple I-beams spaced longitudinally, the I-beams extending circumferentially along the dark cavity section to connect and be disposed on the outside of the dark cavity section, and one end of the I-beams being connected to the corrugated steel plate.

7. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 6, characterized in that, It also includes multiple pipe sheds, which are arranged longitudinally and are spaced apart around the I-beam along the circumference of the dark hole section.

8. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 1, characterized in that, A clay waterproof layer is provided on the upper surface of the backfill section.

9. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 8, characterized in that, The clay waterproof layer has a slope that is inclined toward the gully section.

10. The drainage structure at the entrance of a shallow-buried, biased-pressure tunnel at the confluence of gullies according to claim 1, characterized in that, The pre-buried pipes are made of HDPE.

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