Tunnel portal section structure suitable for bias and valley terrains
By adopting a combined structure of reinforcement units and drainage units in the tunnel opening section of bias and valley terrain, safety and stability problems during construction are solved, landslides and settlement are prevented, and drainage difficulties are solved, and the tunnel is realized Structural safety and stability.
Patent Information
- Application Number
- CN202420714261.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-09
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-04-09
AI Technical Summary
The existing technology lacks tunnel opening section structures suitable for bias and trench terrain, which makes it difficult to ensure safety and structural stability during construction, and is prone to landslides, structural settlement and drainage problems.
A tunnel opening section structure including a hole door unit, an open hole unit, a bias body reinforcement unit and a valley reinforcement unit was designed. The concrete base layer and steel pipe piles were reinforced by pre-reinforced piles and surface grouting steel pipes, and a concrete base layer and steel pipe piles were installed, and the holes were used. Drain the top ditch, roadbed ditch and water diversion canal to prevent landslides and settlement and solve the problem of drainage difficulties.
It effectively prevents surrounding rock collapse and structural cracking caused by biased terrain, reduces structural settlement, ensures construction safety and tunnel stability, and solves the drainage problem in the valley area.
Smart Images
Figure CN222162623U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of tunnels, in particular to a tunnel portal section structure suitable for biased pressure and valley terrains. Background Art
[0002] Eccentric pressure and gullies are two typical adverse terrains in tunnel engineering. In this case, the tunnel structure is subjected to uneven stress, which is easy to cause tunnel disasters. Eccentric pressure terrain may cause landslides during excavation and cracking of the tunnel lining structure; there is a problem of drainage difficulties in the gully area. At the same time, the surrounding rock of the tunnel entrance section passing through the eccentric pressure and gully terrain is generally weak, which is easy to cause the tunnel portal and open hole structure to sink, and then cause structural cracking.
[0003] The prior art basically does not involve the structure of a tunnel portal section that passes through biased pressure and valley areas at the same time. There is a lack of a technical solution that can effectively ensure the safety of such tunnel portal sections during construction and the stability of the tunnel structure, especially to reduce the settlement and cracking of the tunnel structure, prevent the collapse of the tunnel portal section, and facilitate valley drainage.
[0004] In view of this, it is necessary to propose a tunnel portal section structure suitable for biased pressure and valley terrain to solve or at least alleviate the above defects. Utility Model Content
[0005] The main purpose of the utility model is to provide a tunnel portal section structure suitable for biased pressure and valley terrain, so as to solve the technical problem of how to ensure the safety of such a tunnel portal section structure passing through biased pressure and valley areas at the same time during the construction process and the stability of the tunnel structure.
[0006] To achieve the above-mentioned purpose, the utility model provides a tunnel portal section structure suitable for biased and valley terrain, including a portal unit, an open hole unit, a biased body reinforcement unit arranged at the biased mountain, and a valley reinforcement unit arranged at the valley, wherein:
[0007] The biasing body reinforcement unit includes a plurality of first reinforcement units arranged on the outside of the open hole unit and a plurality of second reinforcement units arranged above the open hole unit and located at the valley position; wherein, the lower end of each of the first reinforcement units extends downward to below the open hole unit, the upper end of the first reinforcement unit extends upward to above the open hole unit, the lower end of each of the second reinforcement units extends downward to above the open hole unit, and the upper end of the second reinforcement unit matches the valley position.
[0008] Preferably, the first reinforcement unit is a pre-reinforced pile, and / or the second reinforcement unit is a surface grouting steel pipe.
[0009] Preferably, it also includes an anti-settling unit arranged below the tunnel entrance section, the anti-settling unit includes a concrete base layer laid below the tunnel entrance section and a plurality of rows of steel pipe piles arranged at intervals laterally along the tunnel entrance section, each row of steel pipe piles includes a plurality of steel pipe piles arranged at intervals along the extension direction of the tunnel entrance section, wherein the upper end of each of the steel pipe piles is located in the concrete base layer, and the lower end of the steel pipe pile extends downward into the bedrock.
[0010] Preferably, the portal unit is an end wall type portal.
[0011] Preferably, it also includes a drainage unit, which includes a cave roof ditch, a roadbed ditch and a water diversion channel; wherein the cave roof ditch is arranged at the top of the open hole unit and close to the wall of the end wall type tunnel portal, the cave roof ditch is arranged horizontally along the tunnel and has a drainage slope for draining water from the middle to both sides; the roadbed ditch is arranged on the outside of the open hole unit and extends along the extension direction of the open hole unit, the cave roof ditch discharges water into the roadbed ditch through a pipeline assembly; the water diversion channel is used to drain the water accumulated in the valley into the roadbed ditch.
[0012] Preferably, the drainage unit also includes a drainage hole reserved in the end wall type tunnel door, the drainage hole is located on the outside of the open tunnel unit, the water inlet of the drainage hole is flush with the inner end surface of the end wall type tunnel door, the water outlet of the drainage hole is flush with the outer end surface of the end wall type tunnel door, and the drainage slope of the drainage hole is not less than 3%.
[0013] Preferably, the pipe assembly is a double-wall corrugated pipe.
[0014] Preferably, the cross-section of the cave top ditch is W-shaped, and the drainage slope is not less than 10%.
[0015] Preferably, the drainage slope of the water diversion channel is greater than 10%.
[0016] Preferably, the open hole unit includes an open hole structure body and a rammed earth and stone layer, a clay waterproof layer and a cultivated soil layer sequentially covering the open hole structure body. The lining of the open hole structure body includes a reinforced concrete layer, a first mortar leveling layer, a waterproof layer and a second mortar leveling layer sequentially arranged from the inside to the outside along the radial direction of the tunnel.
[0017] Compared with the prior art, the utility model has the following beneficial effects:
[0018] The utility model provides a tunnel portal section structure suitable for biased pressure and valley terrain, including the technical solution of the utility model, which has the following beneficial effects:
[0019] (1) By setting the first reinforcement unit, the influence of the bias pressure of the rock and soil mass on the near-mountain side on the tunnel structure is effectively isolated. At the same time, by setting the second reinforcement unit in the valley with shallow overburden, the safety of the construction process and the stability of the tunnel structure are ensured, and the surrounding rock collapse and tunnel lining cracking that may be caused by the bias pressure can be effectively prevented. For example, the first reinforcement unit is a pre-reinforcement pile, which is arranged perpendicular to the portal and adopts a "pin" structure, and is arranged at the junction of the first-level side slope and仰坡, which can effectively resist the pressure of the soil mass on the side of the bias pressure mountain and protect the open cut tunnel and portal structure.
[0020] (2) By setting the top ditch of the tunnel, the diversion canal, and the drainage holes, the accumulated water in the valley area is effectively drained to the roadbed ditch, which can effectively solve the drainage problem of the tunnel portal in the valley area.
[0021] (3) By setting the concrete base layer and steel pipe piles at the bottom of the open cut tunnel, the settlement of the portal and open cut tunnel structures caused by geological reasons is effectively reduced, thereby preventing the lining structure from cracking due to settlement. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.
[0023] Figure 1 It is a front view schematic diagram of the overall structure in an embodiment of the present invention;
[0024] Figure 2 It is a plane layout schematic diagram of the overall structure in an embodiment of the present invention;
[0025] Figure 3 It is a longitudinal section schematic diagram of the overall structure in an embodiment of the present invention.
[0026] The realization of the purpose, functional characteristics and advantages of the present invention will be further described with reference to the embodiments and the drawings.
[0027] Explanation of the reference numerals in the drawings:
[0028] 10. Portal unit; 20. Open cut tunnel unit; 210. Open cut tunnel structure body; 30. Bias body reinforcement unit; 310. First reinforcement unit; 311. Pre-reinforcement pile; 40. Valley reinforcement unit; 50. Anti-settlement unit; 510. Concrete base layer; 520. Steel pipe pile; 60. Drainage unit; 610. Top ditch of the tunnel; 620. Roadbed ditch; 630. Diversion canal; 640. Pipeline assembly; 650. Drainage hole; 70. Bias pressure mountain; 80. Valley. DETAILED DESCRIPTION
[0029] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0031] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as described in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0032] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0033] Please see attached Figures 1 to 3 In one embodiment of the utility model, a tunnel portal section structure suitable for biased and valley terrain includes a portal unit 10, an open hole unit 20, a biased body reinforcement unit 30 arranged at a biased mountain 70, and a valley reinforcement unit 40 arranged at a valley 80, wherein the biased body reinforcement unit 30 includes a plurality of first reinforcement units 310 arranged outside the open hole unit 20 and a plurality of second reinforcement units (not shown in the figure) arranged above the open hole unit 20 and located at the valley 80; wherein the lower end of each of the first reinforcement units 310 extends downward to below the open hole unit 20, the upper end of the first reinforcement unit 310 extends upward to above the open hole unit 20, the lower end of each of the second reinforcement units extends downward to above the open hole unit 20, and the upper end of the second reinforcement unit matches the position of the valley 80.
[0034] As a preferred embodiment, the first reinforcement unit 310 is a pre-reinforced pile 311, and / or the second reinforcement unit is a surface grouting steel pipe (not shown).
[0035] Specifically, Figure 1 As shown, the pre-reinforced piles 311 can be set beside the open hole unit 20 near the mountain side. As a preferred example, the pre-reinforced piles 311 are arranged in two rows and staggered. The top of the pre-reinforced piles 311 is at least 5m higher than the top of the open hole unit 20 and can be slightly lower than the ground; the bottom of the pre-reinforced piles 311 is about 12m below the bottom of the open hole unit 20. Cast-in-place reinforced concrete square piles can be used. Preferably, the cross-section of the pre-reinforced piles 311 along the longitudinal direction of the tunnel is 2m, the cross-section of the pre-reinforced piles 311 along the transverse direction of the tunnel is 3m, and the pile core spacing is 5m. Preferably, the pre-reinforced piles 311 are made of C35 reinforced concrete, and the steel bars are all HRB400 grade. The main force-bearing steel bars are arranged on the side close to the mountain. Furthermore, a connecting beam (not shown in the figure) can be set at the top of the pre-reinforced piles 311 to connect the pre-reinforced piles 311. In order to strengthen the integrity of the connecting beam and the pre-reinforced pile 311, the connecting beam concrete and the pre-reinforced pile 311 concrete are poured together.
[0036] Specifically, when pouring the pre-reinforced pile 311, a retaining wall can be set along the entire length of the pile body. Each section of the retaining wall is 1m long, and its length can be adjusted depending on the soil conditions during excavation. The retaining wall is made of C20 concrete, and its strength, thickness and number of steel bars must be ensured during construction to prevent collapse. The gap reserved for pouring between each section of the retaining wall is no more than 250mm, and the gap should be filled immediately after pouring concrete. The retaining wall structure can be constructed in sections using the reverse method. When pouring the upper section of the retaining wall concrete, the longitudinal steel bars of the section must be reserved so that the retaining wall is connected as a whole, and the overlap length of the two sections of the longitudinal steel bars is 250mm. Each section of the retaining wall template must be vertical, and the positive and negative deviations of the adjacent upper and lower sections shall not exceed 10mm. A pile body lock structure is arranged on the top of the pre-reinforced pile 311 to ensure the safety of the excavation of the reinforcement pile, prevent the wellhead from sinking and the inflow of surface water, and facilitate construction. Preferably, the pile body lock structure adopts C20 reinforced concrete with a thickness of 0.5m.
[0037] The surface grouting steel pipe can be set in the shallower section of the far mountain side. The grouting range is preferably: within the plane width range of the tunnel excavation contour line, the bottom of the surface grouting steel pipe is set 0.5m outside the tunnel arch excavation line or extends into the strongly weathered bedrock at a position of not less than 1.5m; outside the plane width range of the tunnel excavation contour line, when the bedrock is above the bottom of the invert arch, the surface grouting steel pipe extends into the strongly weathered bedrock at a position of not less than 1.5m; when the stratum above the bottom of the invert arch is relatively broken and loose, the grouting steel pipe extends below the bottom of the invert arch at a position of not less than 1.5m. Grouting is carried out using φ89×6mm grouting steel pipes, with a spacing of 1.5m×1.5m, a plum blossom arrangement, and pre-grouting using cement single liquid slurry. Preferably, the grouting pressure is 0.5~1.0MPa, the water-cement ratio W / C=1.0, and the cement is P.042.5 ordinary Portland cement. The specific grouting parameters can be determined according to field tests. During the grouting process, the grouting pressure should be increased slowly step by step, and the grouting sequence should be from the outer circle to the center to prevent serious slurry leakage.
[0038] As a preferred embodiment, it also includes an anti-settling unit 50 arranged below the tunnel entrance section, the anti-settling unit 50 includes a concrete base layer 510 laid below the tunnel entrance section and a plurality of rows of steel pipe piles (not shown) arranged at intervals laterally along the tunnel entrance section, each row of steel pipe piles includes a plurality of steel pipe piles 520 arranged at intervals along the extension direction of the tunnel entrance section, wherein the upper end of each of the steel pipe piles 520 is located in the concrete base layer 510, and the lower end of the steel pipe pile 520 extends downward into the bedrock.
[0039] It is worth noting that the tunnel section referred to in this application includes the open tunnel unit 20 and the tunnel door unit 10, which are collectively referred to as the tunnel section. When the geology of the tunnel section is poor, in order to prevent the tunnel door and the open tunnel structure from settling and cracking, a concrete base 510 and a steel pipe pile 520 are set at the bottom of the open tunnel. The concrete base 510 preferably uses a C20 plain concrete cushion layer, and the thickness at the thinnest point is not less than 50cm. The top of the steel pipe pile 520 is embedded in the concrete cushion layer by not less than 30cm, and the bottom of the pile is embedded in the stable bedrock by not less than 100cm. The longitudinal spacing of the steel pipe pile 520 along the tunnel is 100cm, and the transverse spacing along the tunnel is 100 to 200cm. Further, in a preferred example, the middle three rows are arranged vertically, and the steel pipe piles near the outside of the tunnel are extended into the foundation at 5, 10, and 15 degrees, respectively, that is, the angles of the steel pipe pile 520 with the vertical direction are 0°, 5°, 10°, and 15° from the center line of the tunnel to the outside. Steel pipe pile 520 adopts φ108×6mm steel pipe, the inside of the pipe is filled with M30 cement mortar, and the outside of the pipe is wrapped with fine stone concrete. The strength of fine stone concrete is not less than C25, and the outer diameter of steel pipe pile 520 is not less than 20cm.
[0040] Furthermore, the portal unit 10 adopts an end wall portal. In a preferred example, the thickness of the end wall portal is set to 160 cm, and C40 concrete is used. A certain inclination angle is set between the portal wall and the bottom of the wall of the end wall portal, and the inclination is preferably 1:0.15. The portal foundation should be placed on a stable foundation, and debris, stagnant water, and soft mud must be cleared away. The base bearing capacity test should be carried out in advance. For example, if the bearing capacity of the portal wall foundation is less than 0.3MPa, the foundation treatment should be carried out first. The use of an end wall portal can resist the longitudinal thrust of the mountain, while supporting the upward slope on the front of the cave entrance, thereby maintaining the stability of the cave entrance.
[0041] As another preferred embodiment, it also includes a drainage unit 60, which includes a cave roof ditch 610, a roadbed ditch 620 and a water diversion channel 630; wherein the cave roof ditch 610 is arranged at the top of the open hole unit 20 and behind the wall close to the end wall type tunnel portal, the cave roof ditch 610 is arranged horizontally along the tunnel and has a drainage slope for draining water from the middle to both sides; the roadbed ditch 620 is arranged on the outside of the open hole unit 20 and extends along the extension direction of the open hole unit 20, the cave roof ditch 610 discharges water into the roadbed ditch 620 through the pipe assembly 640; the water diversion channel 630 is used to drain the accumulated water in the valley 80 into the roadbed ditch 620.
[0042] Specifically, the cave top ditch 610 can be set 3 to 5 meters outside the cave top excavation line, and the longitudinal slope of the cave top ditch 610 is preferably set to 10%. In a preferred embodiment, the cave top ditch 610 is divided into type I cave top ditch 610 and type II cave top ditch 610. The type I cave top ditch 610 is basin-shaped, and the slope of the ditch wall is preferably 1:1, which is suitable for sections with gentle terrain at the cave entrance; the type II cave top ditch 610 is cylindrical, and the slope of the ditch wall is preferably 1:0.3, which is suitable for sections with steep terrain at the cave entrance. As a preferred example, the pipe assembly 640 is a double-wall corrugated pipe, more preferably a φ400HDPE double-wall corrugated pipe, that is, the cave top ditch 610 is connected to the roadbed ditch 620 through a pre-buried φ400HDPE double-wall corrugated pipe to form an unobstructed drainage path.
[0043] In another preferred example, a 400mm diameter HDPE double-wall corrugated pipe is pre-buried downward on the mountain side of the portal unit 10, and the drainage pipe is perpendicular to the cave top ditch 610. A 400mm diameter PVC drainage pipe is pre-buried in the portal wall at the bottom of the drainage pipe and connected to the roadbed ditch 620. The precipitation on the cave top is discharged from the cave top ditch 610 through the vertically downward double-wall corrugated pipe and PVC drainage pipe to the roadbed ditch 620.
[0044] In another preferred example, the cross-section of the cave top ditch 610 is W-shaped, and the drainage slope is not less than 10%.
[0045] Specifically, the purpose of setting the water diversion channel 630 is to divert the water accumulated in the valley 80 to the roadbed ditch 620 so that it can be discharged smoothly. Preferably, the water inlet end of the water diversion channel 630 is set at the valley 80 outside the top water cutoff, and the water diversion channel 630 can be arranged in the transverse direction of the tunnel. After the water accumulated in the valley 80 is gathered in the water diversion channel 630, it is discharged to the roadbed ditch 620 through the water diversion channel 630. Furthermore, the drainage slope of the water diversion channel 630 is greater than 10%, and the cross section of the water diversion channel 630 can adopt a rectangular section.
[0046] In a preferred example, Figure 2 As shown, the water diversion channel 630 adopts a "C"-shaped water diversion channel 630 for drainage. One end of the water diversion channel 630 is connected to the slope platform ditch, and the other end bypasses the top of the slope and is vertically connected to the roadbed ditch 620.
[0047] Furthermore, the drainage unit 60 also includes a drainage hole 650 reserved in the end wall type tunnel door, the drainage hole 650 is located outside the open tunnel unit 20, the water inlet of the drainage hole 650 is flush with the inner end surface of the end wall type tunnel door, and the water outlet of the drainage hole 650 is flush with the outer end surface of the end wall type tunnel door. That is, the drainage hole 650 is provided on the end wall type tunnel door on both sides of the tunnel opening. As a preferred example, the aperture of the drainage hole 650 is set to 10-15 cm, and the drainage slope is 2%-4%, so that the seepage water behind the wall can be timely drained to the outside of the end wall type tunnel door.
[0048] As a preferred embodiment, the open hole unit 20 includes an open hole structure body 210 and a rammed earth and stone layer (not shown in the figure), a clay waterproof layer (not shown in the figure) and a cultivated soil layer (not shown in the figure) sequentially covering the open hole structure body 210. The lining of the open hole structure body 210 includes a reinforced concrete layer, a first mortar leveling layer, a waterproof layer and a second mortar leveling layer sequentially arranged from the inside to the outside along the radial direction of the tunnel.
[0049] Specifically, Figure 3 As shown, as a preferred example, the reinforced concrete layer is a 60cm thick C40 reinforced concrete, the first mortar leveling layer is a 3cm thick M10 mortar leveling layer, the waterproof layer can be a combination of geotextile + waterproof board + geotextile, and the second mortar leveling layer is a 3cm thick M10 mortar leveling layer; preferably, the thickness of the cultivated soil layer is 50cm, and the thickness of the clay waterproof layer is 50cm. It should be noted that the foundation of the open hole structure body 210 should be placed on a stable foundation, and debris, stagnant water, and soft mud must be cleared away, and the base bearing capacity test should be carried out. For example, if the bearing capacity of the foundation of the tunnel wall is less than 0.3MPa, the foundation treatment should be carried out first. The surface of the cultivated soil layer has a certain slope, so that the water can flow smoothly to the cave top ditch 610. Preferably, the slope is 2%.
[0050] In addition, temporary slope protection at the cave entrance can be achieved by using anchor net spraying. Preferably, 3m long φ22 mortar anchors are used, with a spacing of 1.2m and a plum blossom shape. φ8 steel mesh is used, with a grid of 25cm×25cm and C25 sprayed concrete with an average thickness of 10cm. Permanent protection of the back slope can be achieved by using pipe net spraying combined with greening protection.
[0051] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. A tunnel portal structure suitable for biased and valley terrain, It is characterized in that It includes a tunnel gate unit, an open tunnel unit, a biased body reinforcement unit located at the biased mountain, and a valley reinforcement unit located at the valley, wherein: The biasing body reinforcement unit includes a plurality of first reinforcement units arranged on the outside of the open hole unit and a plurality of second reinforcement units arranged above the open hole unit and located at the valley position; wherein, the lower end of each of the first reinforcement units extends downward to below the open hole unit, the upper end of the first reinforcement unit extends upward to above the open hole unit, the lower end of each of the second reinforcement units extends downward to above the open hole unit, and the upper end of the second reinforcement unit matches the valley position.
2. The tunnel portal section structure suitable for biased and valley terrain according to claim 1, It is characterized in that The first reinforcement unit is a pre-reinforced pile, and / or the second reinforcement unit is a surface grouting steel pipe.
3. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 1, It is characterized in that It also includes an anti-settling unit arranged below the tunnel entrance section, the anti-settling unit includes a concrete base layer laid below the tunnel entrance section and a plurality of rows of steel pipe piles arranged at intervals laterally along the tunnel entrance section, each row of steel pipe piles includes a plurality of steel pipe piles arranged at intervals along the extension direction of the tunnel entrance section, wherein the upper end of each of the steel pipe piles is located in the concrete base layer, and the lower end of the steel pipe pile extends downward into the bedrock.
4. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 3, It is characterized in that The portal unit adopts an end wall type portal.
5. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 4, It is characterized in that It also includes a drainage unit, which includes a cave roof ditch, a roadbed ditch and a water diversion channel; wherein the cave roof ditch is arranged at the top of the open tunnel unit and close to the wall of the end wall type tunnel portal, the cave roof ditch is arranged horizontally along the tunnel and has a drainage slope for draining water from the middle to both sides; the roadbed ditch is arranged on the outside of the open tunnel unit and extends along the extension direction of the open tunnel unit, the cave roof ditch discharges water into the roadbed ditch through a pipeline assembly; the water diversion channel is used to drain the water accumulated in the valley into the roadbed ditch.
6. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 5, It is characterized in that The drainage unit also includes a drainage hole reserved in the end wall type tunnel door, the drainage hole is located on the outside of the open tunnel unit, the water inlet of the drainage hole is flush with the inner end surface of the end wall type tunnel door, the water outlet of the drainage hole is flush with the outer end surface of the end wall type tunnel door, and the drainage slope of the drainage hole is not less than 3%.
7. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 5, It is characterized in that The pipeline component is a double-wall corrugated pipe.
8. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 5, It is characterized in that The cross section of the cave top ditch is W-shaped, and the drainage slope is not less than 10%.
9. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 5, It is characterized in that The drainage slope of the water diversion channel is greater than 10%.
10. The tunnel portal section structure suitable for biased pressure and valley terrain according to claim 1, It is characterized in that The open hole unit includes an open hole structure body and a rammed earth and stone layer, a clay waterproof layer and a cultivated soil layer sequentially covering the open hole structure body. The lining of the open hole structure body includes a reinforced concrete layer, a first mortar leveling layer, a waterproof layer and a second mortar leveling layer sequentially arranged from the inside to the outside along the radial direction of the tunnel.