A tunnel heat preservation layer structure in a seasonal frozen soil area and a construction method

Abstract

This invention relates to the field of tunnel insulation technology, specifically disclosing a tunnel insulation layer structure and construction method for tunnels in seasonally frozen soil areas. The structure includes a tunnel opening, an inner insulation layer, and an outer insulation layer. Backfill soil is required above the tunnel opening. The inner insulation layer is located on the inner wall of the tunnel opening, and the outer insulation layer is located within the backfill soil. Detachable telescopic mechanisms are installed on both sides of the tunnel opening. A protective shell is connected to the other end of each telescopic mechanism, and the outer insulation layer is installed inside the protective shell. Several sets of anchor bolts are installed below the protective shell. The telescopic mechanism includes a telescopic rod, which comprises a fixed rod and a movable rod. The movable rod passes through the fixed rod, which is hinged to a connecting sleeve. The movable rod is hinged to the protective shell. A temporary support assembly is provided between the fixed rod and the movable rod. This invention solves the technical problem that backfill soil tends to shift over time, reducing its protective effect on the tunnel opening and thus shortening its service life.

Description

Technical Field

[0001] This invention relates to the field of tunnel insulation technology, and specifically discloses a tunnel insulation layer structure and construction method in seasonally frozen soil areas. Background Technology

[0002] As the country's transportation becomes more and more developed, highways and tunnels are gradually being built in permafrost areas. After the tunnel is built, due to the low soil temperature, in order to prevent the tunnel opening from being damaged by freezing, it is usually necessary to add a layer of insulation to the backfill soil to reduce the impact of temperature changes on the soil, ensure the stable operation of equipment in the tunnel, provide thermal insulation for the equipment, and prevent the equipment in the tunnel from becoming unusable due to excessively low temperatures.

[0003] The tunnel insulation layer is usually fixed to the outer or inner wall of the tunnel and cannot insulate the backfill soil. The backfill soil is usually divided into a crushed stone layer, a clay waterproof layer, and a planting soil layer. The crushed stone layer has high strength, load-bearing capacity, and good thermal stability, and is mainly used to reinforce the soil and protect the tunnel opening. The clay waterproof layer is mainly used for waterproofing. In permafrost areas, the soil will expand or contract due to temperature changes. When the soil expands and contracts, the backfill soil may shift over time. After the backfill soil shifts, it cannot provide better protection for the tunnel opening, thus reducing the service life of the tunnel opening. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a tunnel insulation layer structure and construction method in seasonally frozen soil areas, so as to solve the technical problem that the backfill soil will shift over time, which reduces the protective effect of the tunnel opening and thus reduces the service life of the tunnel opening.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a tunnel insulation layer structure for seasonally frozen soil areas, comprising a tunnel opening, an inner insulation layer, and an outer insulation layer. Backfill soil is required above the tunnel opening. The inner insulation layer is located on the inner wall of the tunnel opening, and the outer insulation layer is located within the backfill soil. The backfill soil includes a planting soil layer, a clay waterproofing layer, and a gravel layer, arranged from top to bottom in the order of planting soil layer, clay waterproofing layer, and gravel layer. Detachable telescopic mechanisms are provided on both sides of the tunnel opening. The other end of each telescopic mechanism is connected to the outer insulation layer. The outer insulation layer includes a protective shell and insulation material. Several sets of anchor bolts are provided below the protective shell. The telescopic mechanism includes a telescopic rod, which includes a fixed rod and a movable rod. A movable rod is inserted into the fixed rod, which is hinged to the connecting sleeve. A third connecting block is fixedly connected to the tunnel opening, and the connecting sleeve is fitted onto the third connecting block. Two sets of elastic components for increasing friction are provided at the hinge point between the fixed rod and the connecting sleeve. Each elastic component includes a connecting ring, on which a first connecting block is provided, and on the fixed rod a second connecting block. The first connecting block is slidably engaged within the second connecting block. A first spring is provided between the connecting ring and the fixed rod, with both ends fixedly connected to the connecting ring and the fixed rod, respectively. The connecting ring is fitted onto the hinge axis between the fixed rod and the connecting sleeve. A temporary support assembly is provided between the fixed rod and the movable rod. By adjusting the position of the top of the movable rod through the telescopic mechanism, the outer insulation layer is fixed in a designated position, providing insulation for the tunnel opening and part of the backfill soil. This prevents the backfill soil from thermally expanding and contracting, thereby extending the service life of the tunnel opening.

[0006] Furthermore, the temporary support assembly includes a first locking block, which is fixedly connected to the bottom end of the movable rod. The fixed rod has a first sliding groove, a second sliding groove, and several sets of locking slots. The first locking block is slidably engaged in the first sliding groove, and a movable sleeve is slidably engaged in the second sliding groove. A first movable block is provided on the first locking block, and the first movable block is slidably engaged in the movable sleeve. A second spring is provided inside the movable sleeve, with both ends of the second spring fixedly connected between the bottom end of the movable sleeve and the first movable block, respectively. The temporary support assembly can fix the movable rod at a specified height. After connecting the telescopic rod to the protective shell, it can ensure that the protective shell moves slightly with soil settlement, avoiding voids that could reduce the insulation effect.

[0007] Furthermore, a hinge block is hinged to the bottom of the protective shell. The hinge block is connected to the movable rod via a fixing mechanism. The fixing mechanism includes the hinge block, and the movable rod passes through the hinge block. Two sets of second locking blocks are provided within the hinge block, and two sets of second locking slots are provided on the movable rod. The two sets of second locking blocks are respectively locked into the two sets of second locking slots. Two sets of unidirectional moving components are provided between the movable rod and the hinge block. The fixing mechanism is used to connect the movable rod and the protective shell, preventing the protective shell from separating from the movable rod during use and causing the protective shell to move with the soil layer.

[0008] Furthermore, the unidirectional movement component includes a third locking block, a sliding groove formed within the hinge block, and the third locking block slidably engaging within the sliding groove. A third spring is disposed within the sliding groove, with its two ends respectively fixedly connected to the locking block and the bottom end of the sliding groove. A third locking slot is formed on the movable rod, and the third locking block engages within the third locking slot. The unidirectional movement component fixes the movable rod within the hinge block, preventing the movable rod from separating from the hinge block.

[0009] Furthermore, the protective shell includes a first mating block and a second mating block. The first mating block has several sets of second limiting grooves, and the second mating block has several sets of second limiting blocks. These second limiting blocks are respectively engaged within the second limiting grooves. The insulation material is located between the first and second mating blocks. A U-shaped groove is formed on one side of the first mating block, and a U-shaped block is formed on the other side. The U-shaped block is engaged within the U-shaped groove formed on an adjacent first mating block. The first and second mating blocks are fixed together by several sets of clamping mechanisms. The protective shell is used to fix the insulation material and can prevent backfill soil from damaging the insulation material, reducing its insulation effect, and preventing thermal expansion and contraction of the backfill soil below the outer insulation layer from damaging the tunnel opening and thus reducing its service life.

[0010] Furthermore, the clamping mechanism includes two sets of first fixing blocks, which are respectively fixedly connected to the first mating block and the second mating block. Each of the two sets of first fixing blocks is fixedly connected to a second fixing block. Both sets of first fixing blocks are inserted into a fixing sleeve, and the two sets of second fixing blocks are engaged within the fixing sleeve. A second movable block is provided on the fixing sleeve, and a first limiting block is provided on the second movable block. A first limiting groove is formed on the fixing sleeve, and the first limiting block is slidably engaged within the first limiting groove. One side of the second movable block contacts the second mating block. A rubber block is fixedly connected to the fixing sleeve, and both sides of the rubber block contact the fixing sleeve and the second movable block, respectively. A first rectangular block is provided at one end of the rubber block, and a rectangular groove is formed on the fixing sleeve, within which the first rectangular block is engaged. The clamping mechanism is used to fix the first mating block and the second mating block, enabling them to better protect the insulation material and effectively prevent damage to it.

[0011] Furthermore, both the connecting sleeve and the third connecting block are provided with locking holes, and locking pins are inserted into the two sets of locking holes. The locking pins fix the telescopic rod to the tunnel opening.

[0012] Furthermore, the external insulation layer is positioned between the tunnel opening and the gravel layer, or between the gravel layer and the clay waterproof layer, or between the clay waterproof layer and the planting soil layer, or above the planting soil layer. By changing the position of the external insulation layer, the tunnel opening is protected.

[0013] A method for constructing a tunnel insulation layer in a seasonally frozen soil region includes:

[0014] S1: First, lay an inner insulation layer on the inner wall of the tunnel opening, then put the connecting sleeve on the third connecting block, and then use a pin to fix the connecting sleeve to the third connecting block, so that the telescopic rod is fixed to the tunnel opening;

[0015] S2: Adjust the length of the two sets of telescopic rods so that the top of the movable rod is at the specified height. Then rotate the two sets of telescopic rods to a specified angle with the bottom surface. The connecting ring and the first spring increase the friction between the fixed rod and the connecting sleeve, ensuring that the telescopic rod will not rotate on the connecting sleeve without being affected by external force. By adjusting the length and angle of the telescopic rods, the distance between the tops of the two sets of movable rods is exactly the same as the distance between the two sets of hinge seats on the first mating block, which makes it convenient for the staff to install the first mating block.

[0016] S3: Backfilling and laying of the outer insulation layer: Backfill the gravel layer, clay waterproof layer and planting soil layer in the order from bottom to top. When the backfilling reaches the position of laying the outer insulation layer, stop backfilling and lay the outer insulation layer. At the same time, move the first mating block between the two sets of telescopic rods, then rotate the movable rod and then insert the movable rod into the hinge block to make the movable rod hinged with the first mating block. This facilitates the backfilling of the soil and also makes it easier for the staff to connect the protective shell to the telescopic rod.

[0017] S4: Lay the insulation material inside the first mating block, then move the second mating block above the first mating block and align the limiting block with the limiting groove, then move the second mating block downwards and clamp it onto the first mating block so that the two sets of first fixing blocks come into contact; clamp the second mating block onto the first mating block to protect the outer insulation layer.

[0018] S5: Place the fixing sleeve onto the two sets of first blocks, then rotate the fixing sleeve, and then move the second movable block until it contacts the second mating block. Then move the rubber block to fit the first rectangular block into the rectangular groove, fixing the second movable block. The second movable block mates with the second fixing block to fix the fixing sleeve onto the two sets of first fixing blocks, and then continue backfilling. Completely fix the first mating block and the second mating block, and then backfill with the remaining backfill soil.

[0019] The working principle and beneficial effects of this solution are as follows:

[0020] When the backfill sequence for the tunnel opening is, from bottom to top, a layer of crushed stone, an external insulation layer, a clay waterproofing layer, and a planting soil layer, it is suitable for areas with large temperature differences. This avoids the thermal expansion and contraction of the crushed stone layer due to temperature changes, which can damage the tunnel opening and extend its service life. Conversely, when the backfill sequence is again, this method is suitable for areas with high humidity. The external insulation layer insulates the clay waterproofing layer, extending its lifespan. The waterproof layer protects the tunnel opening for a period of time, preventing groundwater from eroding it. When the tunnel opening is backfilled from bottom to top in the order of gravel layer, clay waterproof layer, planting soil layer, and external insulation layer, it is suitable for low-temperature and high-altitude areas, as it avoids the planting soil layer from changing terrain due to temperature differences during seasonal transitions. When the tunnel opening is backfilled from bottom to top in the order of external insulation layer, gravel layer, clay waterproof layer, and planting soil layer, it can maximize the insulation effect of the tunnel opening, and the protection effect of the tunnel opening is optimal.

[0021] When installing the inner insulation layer, simply attach it to the inner wall of the tunnel opening. For the outer insulation layer, first adjust the angle and length of the telescopic mechanism to reach the designated position and angle. Then, backfill the tunnel opening until the outer insulation layer is laid. Stop backfilling, fix the movable rod to the first mating block using the fixing mechanism, place the insulation material inside the first mating block, and then clip the second mating block onto the first mating block to protect the insulation material. Secure the first and second mating blocks using the clamping mechanism, and then continue backfilling the remaining backfill soil. The combination of the inner and outer insulation layers insulates the tunnel opening and part of the backfill soil, extending the service life of the tunnel opening. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment;

[0023] Figure 2 Exploded view of an embodiment;

[0024] Figure 3 This is an enlarged schematic diagram of region A in the embodiment;

[0025] Figure 4 This is an enlarged schematic diagram of region B in the embodiment;

[0026] Figure 5 This is an enlarged schematic diagram of region C in the embodiment;

[0027] Figure 6 This is a schematic diagram of the internal structure of the telescopic rod in the embodiment;

[0028] Figure 7 This is an enlarged schematic diagram of region D in the embodiment;

[0029] Figure 8 This is a longitudinal sectional view of the tunnel opening in Example 1;

[0030] Figure 9 This is a longitudinal sectional view of the tunnel opening in Example 2;

[0031] Figure 10 This is a longitudinal sectional view of the tunnel opening in Example 3;

[0032] Figure 11 This is a longitudinal sectional view of the tunnel opening in Example 4.

[0033] The following are the markings in the attached diagram: 1. Tunnel opening; 2. Protective shell; 3. First mating block; 4. Second mating block; 8. Second limiting block; 9. Second limiting groove; 10. Third connecting block; 11. Locking pin; 12. Locking hole; 13. U-shaped groove; 14. U-shaped block; 15. Anchor bolt; 16. Outer insulation layer; 17. Inner insulation layer; 18. Crushed stone layer; 19. Clay waterproof layer; 20. Planting soil layer.

[0034] Telescopic rod 501, fixed rod 502, movable rod 503, connecting sleeve 504, connecting ring 505, first spring 506, first connecting block 507, second connecting block 508, first locking block 509, first movable block 510, movable sleeve 511, second spring 512, first sliding groove 513, first locking groove 514, second sliding groove 515;

[0035] Hinged block 601, second locking block 602, second locking groove 603, third locking block 604, third spring 605, sliding groove 606, third locking groove 607;

[0036] First fixing block 701, second fixing block 702, fixing sleeve 703, second movable block 704, first limiting block 705, first limiting groove 706, rubber block 707, first rectangular block 708, rectangular groove 709. Detailed Implementation

[0037] The following detailed description illustrates the specific implementation methods:

[0038] Example 1:

[0039] like Figures 1 to 8 As shown, a tunnel insulation layer structure for seasonally frozen soil regions is disclosed, including a tunnel opening 1, an inner insulation layer 17, and an outer insulation layer 16. Backfill soil is required above the tunnel opening 1. The inner insulation layer 17 is located on the inner wall of the tunnel opening 1, and the outer insulation layer 16 is located within the backfill soil. The backfill soil includes a planting soil layer 20, a clay waterproof layer 19, and a gravel layer 18. The planting soil layer 20 is 30 cm thick, and the clay waterproof layer 19 is 60 cm thick. The backfilling sequence of the tunnel opening 1 from bottom to top is gravel layer 18, outer insulation layer 16, clay waterproof layer 19, and planting soil layer 20.

[0040] Telescopic mechanisms are installed on both sides of the tunnel opening 1. Each telescopic mechanism includes a connecting sleeve 504. A first movable block 510 is installed on the tunnel opening 1 and is fitted inside the tunnel opening 1. Both the connecting sleeve 504 and the first movable block 510 have locking holes 12, and locking pins 11 are inserted into the two sets of locking holes 12. A telescopic rod 501 is hinged to the connecting sleeve 504. Elastic components are installed on both sides of the telescopic rod 501, located at the hinge joint between the connecting sleeve 504 and the telescopic rod 501. At this location, the elastic component includes a connecting ring 505, a first spring 506 is disposed between the connecting ring 505 and the telescopic rod 501, the two ends of the first spring 506 are respectively fixedly connected to the connecting ring 505 and the telescopic rod 501, a first connecting block 507 is disposed on the connecting ring 505, and a second connecting block 508 is disposed on the telescopic rod 501, the first connecting block 507 is slidably engaged with the second connecting block 508, and the connecting ring 505 and the first spring 506 are fitted onto the hinge shaft of the hinge seat; the telescopic rod 501 includes a fixed rod 502 and a movable rod 503. The movable rod 503 is inserted into the fixed rod 502. A temporary support assembly is provided between the fixed rod 502 and the movable rod 503. The temporary support assembly includes a first locking block 509, which is trapezoidal and fixedly connected to the lower end of the movable rod 503. A first movable block 510 is provided on the first locking block 509. The fixed rod 502 has a first sliding groove 513, a second sliding groove 515, and several sets of first sliding grooves 513, 514, and 515, respectively. The first locking block 509 is slidably locked in the first sliding groove 513 in the slot 514. The movable sleeve 511 is slidably locked in the second sliding groove 515. The movable sleeve 511 is provided with a limit block. The first movable block 510 is slidably locked in the movable sleeve 511. The movable sleeve 511 is provided with a second spring 512. The second spring 512 is located between the movable sleeve 511 and the first movable block 510. The two ends of the second spring 512 are fixedly connected to the movable sleeve 511 and the first movable block 510 respectively.

[0041] A fixing mechanism is provided at the top of the movable rod 503. The fixing mechanism includes a hinge block 601, which is fitted onto the movable rod 503. Two sets of second locking blocks 602 are provided inside the hinge block 601. Two sets of second locking slots 603 are provided on the movable rod 503. The two sets of second locking blocks 602 are respectively locked into the two sets of second locking slots 603. Two sets of one-way moving components are provided between the movable rod 503 and the hinge sleeve. The one-way moving components include a third locking block 604. A sliding groove 606 is provided on the hinge block 601. The third locking block 604 is slidably locked into the sliding groove 606. A third spring 605 is provided in the sliding groove 606. The two ends of the third spring 605 are fixedly connected to the bottom end of the sliding groove 606 and the third locking block 604, respectively. A third locking slot 607 is provided on the movable rod 503. The third locking block 604 is locked into the third locking slot 607. The hinge seat is hinged to the bottom end of the protective shell 2.

[0042] The outer insulation layer 16 includes a protective shell 2 and insulation material. The protective shell 2 includes a first mating block 3 and a second mating block 4. A hinge seat is hinged to the first mating block 3. The first mating block 3 has several sets of second limiting grooves 9. The second mating block 4 has several sets of second limiting blocks 8, which are respectively engaged in the several sets of second limiting grooves 9. A U-shaped groove 13 is provided on one side of the first mating block 3, and a U-shaped block 14 is provided on the other side of the first mating block 3. The U-shaped block 14 is engaged in the U-shaped groove 13 on the adjacent first mating block 3. Several sets of anchor rods 15 are provided below the first mating block 3, and the anchor rods 15 are all inserted into the backfill soil. Several sets of clamping mechanisms are provided between the first mating block and the second mating block 4. The clamping mechanism includes a first fixing block 701. The first mating block 3 and the second mating block 4 are both provided with a first fixing block 701. The two sets of first mating blocks 3 are both provided with a second fixing block 701. The fixed block 702 has two sets of first fixed blocks 701 that form a cylinder after contact. A fixed sleeve 703 is fitted on the two sets of first fixed blocks 701. Two sets of LU-shaped grooves 13 are opened in the fixed sleeve 703. The two sets of second fixed blocks 702 are respectively slidably locked in the two sets of LU-shaped grooves 13. A second movable block 704 is provided on the fixed sleeve 703. A first limiting block 705 is provided on the second movable block 704. A first limiting groove 706 is opened on the fixed sleeve 703. The first limiting block 705 is slidably locked in the first limiting groove 706 and contacts the second mating block 4. A rubber block 707 is fixedly connected to the fixed sleeve 703. The rubber block 707 is locked in the gap between the fixed sleeve 703 and the second movable block 704. A first rectangular block 708 is provided at one end of the rubber block 707. A rectangular groove 709 is opened on the fixed sleeve 703. The first rectangular block 708 is locked in the rectangular groove 709.

[0043] In practice:

[0044] S1: First, lay an inner insulation layer 17 on the inner wall of the tunnel opening 1. Then, put the connecting sleeve 504 on the third connecting block 10, align the connecting sleeve 504 and the locking hole 12 on the third connecting block 10, and then insert the locking pin 11 into the locking hole 12 to fix the connecting sleeve 504 and the third connecting block 10, thereby fixing the telescopic rod 501 to the tunnel opening 1.

[0045] S2: Adjust the length of the two sets of telescopic rods 501. First, rotate the movable rod 503 to cause the first locking block 509 to separate from the locking slot and move into the first sliding groove 513. When the first locking block 509 moves, it causes the first movable block 510 to move. The first movable block 510 slides in the movable sleeve 511, while compressing the second spring 512. Then, move the movable rod 503 upward, causing the first locking block 509 to slide on the first sliding groove 513. The first locking block 509 causes the movable sleeve 511 to slide on the second sliding groove 515 until the top of the movable rod 503 is at the specified height. Then, release the movable rod 503, and the spring slowly returns to its initial state, causing... The first movable block 510 slides within the movable sleeve 511. The first movable block 510 drives the first locking block 509 and the movable rod 503 to rotate, causing the first locking block 509 to separate from the first sliding groove 513 until it is locked into the groove. Through the cooperation of the first locking block 509 and the groove, the movable rod 503 is fixed in the fixed rod 502. Then, the two sets of telescopic rods 501 are rotated to form a specified angle with the bottom surface. The first spring 506 is always in a compressed state. The connecting ring 505 and the first spring 506 are used to increase the friction between the fixed rod 502 and the connecting sleeve 504, ensuring that the telescopic rod 501 will not rotate on the connecting sleeve 504 without being affected by external force. The temporary support assembly ensures that when the movable rod 503 is not connected to the protective shell 2, the movable rod 503 will not rise or fall within the fixed rod 502. When the movable rod 503 is connected to the protective shell 2, the movable rod 503 can move with the movement of the protective shell 2, thus avoiding the separation of the protective shell 2 and the movable rod 503 due to uncontrollable factors during use, which would reduce the insulation effect of the insulation layer on the tunnel opening 1.

[0046] S3: First, backfill the crushed stone layer 18, then pause the backfilling and lay the outer insulation layer 16. Move the first mating block 3 between the two sets of telescopic rods 501, align the movable rod 503 with the hinge block 601, and then rotate the movable rod 503. At this time, the first locking block 509 separates from the slot and moves into the first sliding groove 513. Then, the movable rod 503 is locked into the hinge block 601. When the movable rod 503 is locked into the hinge block 601, the movable block first pushes the third locking block 604, causing the third locking block 604 to slide in the sliding groove 606 until... The third locking block 604 is fully positioned within the sliding groove 606, simultaneously compressing the third spring 605. When the movable block moves to the point where the third locking block 604 aligns with the third locking groove 607, the third spring 605 returns to its initial state, causing the third locking block 604 to slide within the sliding groove 606, thus locking the third locking block 604 into the third locking groove 607. This fixes the movable rod 503 to the hinge block 601, allowing the movable rod 503 to hinge with the first mating block 3. Simultaneously, the U-shaped block 14 is locked into the U-shaped groove 13 on the adjacent first mating block 3. The telescopic rod 501 is fixed to the protective shell 2 via a fixing mechanism, ensuring that the protective shell 2, telescopic rod 501, and tunnel opening 1 are securely connected. This guarantees that the outer insulation layer 16 is always positioned above the tunnel opening 1, providing insulation for the tunnel opening 1 and part of the backfill soil, thereby extending the service life of the tunnel opening 1.

[0047] S4: Several sets of anchor rods 15 are driven into the gravel layer 18 and fixedly connected to the first mating block 3. Then, the insulation material is laid inside the first mating block 3. Next, the second mating block 4 is moved above the first mating block 3 so that the limiting block is aligned with the limiting groove. Then, the second mating block 4 is moved downward and clamped onto the first mating block 3 so that the two sets of first fixing blocks 701 are in contact. The second mating block 4 is initially clamped onto the first mating block 3 to protect the insulation material. The anchor rods 15 are used to fix the outer insulation layer 16 and play an auxiliary fixing role to prevent the expansion rod 501 from failing to fix the outer insulation layer 16 above the tunnel opening 1 due to insufficient strength.

[0048] S5: Align the LU-shaped groove 13 on the fixing sleeve 703 with the second fixing block 702, then fit the fixing sleeve 703 onto the two sets of first movable blocks 510, so that the second fixing block 702 slides in the LU-shaped groove 13. Then rotate the fixing sleeve 703 to drive the second fixing block 702 to slide in the LU-shaped groove 13, so that the fixing sleeve 703 is fixed on the first fixing block 701. Then move the second movable block 704 to drive the first limiting block 705 to slide up the first limiting groove 706. The mechanism moves the second movable block 704 to contact the second mating block 4, then moves the rubber block 707 to engage it in the gap between the fixing sleeve 703 and the second movable block 704. The first rectangular block 708 is then engaged in the rectangular groove 709, fixing the second movable block 704. The second movable block 704 engages with the second fixing block 702, fixing the fixing sleeve 703 to the two sets of first fixing blocks 701. Then, the clay waterproof layer 19 and the planting soil layer 20 are backfilled sequentially. The clamping mechanism is used to fix the first mating block 3 and the second mating block 4, preventing the planting soil above the outer insulation layer 16 from shifting due to thermal expansion and contraction, which would cause the second mating block 4 to move, separating the first mating block 3 from the second mating block 4, damaging the insulation material, reducing the insulation effect of the outer insulation layer 16, and thus reducing the service life of the tunnel opening 1.

[0049] Crushed stone material has high strength and load-bearing capacity, so crushed stone layer 18 is suitable for laying at the bottom to serve as a foundation. Crushed stone layer 18 is not easily affected by temperature changes. This embodiment is suitable for areas with large temperature differences, avoiding thermal expansion and contraction of crushed stone layer 18 due to large temperature differences, which could damage the tunnel opening 1 and thus improve the service life of tunnel opening 1. At the same time, it can protect the electrical appliances in the tunnel so that they can be used normally. A clay waterproof layer 19 is set above the outer insulation layer 16. The clay waterproof layer 19 has good impermeability and can effectively prevent water penetration. It can prevent groundwater from penetrating the outer insulation layer 16 and eroding the outer insulation layer 16, which would reduce the service life of the outer insulation layer 16.

[0050] Example 2:

[0051] The difference from Example 1 is that: Figures 1 to 7 and Figure 9 As shown,

[0052] The backfilling sequence of the tunnel opening 1 from bottom to top is as follows: gravel layer 18, clay waterproof layer 19, external insulation layer 16, and planting soil layer 20.

[0053] In S3, the gravel layer 18 and the clay waterproof layer 19 are backfilled in sequence first, and then the backfilling is paused and the external insulation layer 16 is laid.

[0054] In S5, then continue to backfill the planting soil layer 20 in sequence.

[0055] This embodiment is suitable for areas with high humidity. The outer insulation layer 16 can insulate the clay waterproof layer 19, preventing the clay waterproof layer 19 from slowly moving due to thermal expansion and contraction. After a long period of time, it will not be able to provide waterproof protection for the tunnel opening 1. It can more effectively prevent groundwater from eroding the tunnel opening 1, thereby extending the life of the tunnel opening 1.

[0056] Example 3:

[0057] The difference from Example 1 is that: Figures 1 to 7 and Figure 10 As shown,

[0058] The backfilling sequence of the tunnel opening 1 from bottom to top is as follows: gravel layer 18, clay waterproof layer 19, planting soil layer 20, and external insulation layer 16.

[0059] In S3, the gravel layer 18, the clay waterproof layer 19, and the planting soil layer 20 are backfilled in sequence, and then the outer insulation layer 16 is laid.

[0060] In S5, backfilling is not required.

[0061] This embodiment is suitable for low-temperature and cold regions. Since the planting soil layer 20 is prone to significant topographic changes during seasonal transitions, the use of the outer insulation layer 16 for insulation can prevent significant topographic changes in the planting soil layer 20.

[0062] Example 4:

[0063] The difference from Example 1 is that: Figures 1 to 7 and Figure 11 As shown,

[0064] The backfilling sequence of the tunnel opening 1 from bottom to top is: external insulation layer 16, crushed stone layer 18, clay waterproof layer 19, and planting soil layer 20.

[0065] In this embodiment, no telescopic mechanism or fixing mechanism is provided. The outer insulation layer 16 is directly fixed above the tunnel opening 1 through the protective shell 2. There is no need to use a telescopic mechanism or fixing mechanism to fix the protective shell 2. It is only necessary to fix the protective shell 2 above the tunnel opening 1. There is also no need to use anchor rods 15.

[0066] This embodiment can protect the use of electrical appliances inside the tunnel and has the best heat preservation effect on the open section 1 of the tunnel.

[0067] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics in the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or its practicality.

Claims

1. A tunnel heat preservation layer structure in a seasonally frozen ground region, characterized by: The system includes a tunnel opening, an inner insulation layer, and an outer insulation layer. Backfill soil is required above the tunnel opening. The inner insulation layer is located on the inner wall of the tunnel opening, and the outer insulation layer is located within the backfill soil. The backfill soil includes a planting soil layer, a clay waterproofing layer, and a gravel layer, arranged from top to bottom in the order of planting soil, clay waterproofing layer, and gravel layer. Detachable telescopic mechanisms are installed on both sides of the tunnel opening. The other end of each telescopic mechanism is connected to the outer insulation layer, which includes a protective shell and insulation material. Several sets of anchor bolts are installed below the protective shell. The telescopic mechanism includes a telescopic rod, which includes a fixed rod and a movable rod. The movable rod is inserted into the fixed rod, and the fixed rod is hinged. A third connecting block is fixedly connected to the tunnel opening and attached to the connecting sleeve. The connecting sleeve is fitted onto the third connecting block. Two sets of elastic components for increasing friction are provided at the hinge point between the fixed rod and the connecting sleeve. Each elastic component includes a connecting ring, on which a first connecting block is provided, and on the fixed rod a second connecting block. The first connecting block is slidably fitted into the second connecting block. A first spring is provided between the connecting ring and the fixed rod, with both ends of the first spring fixedly connected to the connecting ring and the fixed rod, respectively. The connecting ring is fitted onto the hinge axis between the fixed rod and the connecting sleeve. A temporary support component is provided between the fixed rod and the movable rod.

2. The thermal insulation layer structure for tunnels in seasonally frozen soil areas according to claim 1, characterized in that: The temporary support assembly includes a first locking block, which is fixedly connected to the bottom end of the movable rod. The fixed rod has a first sliding groove, a second sliding groove, and several sets of locking slots. The first locking block is slidably locked in the first sliding groove. A movable sleeve is slidably locked in the second sliding groove. A first movable block is provided on the first locking block. The first movable block is slidably locked in the movable sleeve. A second spring is provided in the movable sleeve. The two ends of the second spring are respectively fixedly connected between the bottom end of the movable sleeve and the first movable block.

3. The thermal insulation layer structure for tunnels in seasonally frozen soil areas according to claim 2, characterized in that: A hinge block is hinged to the bottom of the protective shell. The hinge block is connected to the movable rod through a fixing mechanism. The fixing mechanism includes the hinge block. The movable rod is inserted into the hinge block. Two sets of second locking blocks are provided in the hinge block. Two sets of second locking slots are opened on the movable rod. The two sets of second locking blocks are respectively locked into the two sets of second locking slots. Two sets of unidirectional moving components are provided between the movable rod and the hinge block.

4. The thermal insulation layer structure for tunnels in seasonally frozen soil areas according to claim 3, characterized in that: The unidirectional moving component includes a third locking block, a sliding groove is provided in the hinge block, the third locking block is slidably locked in the sliding groove, a third spring is provided in the sliding groove, the two ends of the third spring are respectively fixedly connected to the locking block and the bottom end of the sliding groove, a third locking slot is provided on the movable rod, and the third locking block is locked in the third locking slot.

5. The tunnel insulation layer structure in seasonally frozen soil areas according to claim 4, characterized in that: The protective shell includes a first mating block and a second mating block. The first mating block has several sets of second limiting grooves, and the second mating block has several sets of second limiting blocks. The several sets of second limiting blocks are respectively fitted into the several sets of second limiting grooves. The thermal insulation material is located between the first mating block and the second mating block. A U-shaped groove is provided on one side of the first mating block, and a U-shaped block is provided on the other side of the first mating block. The U-shaped block is fitted into the U-shaped groove provided on the adjacent first mating block. The first mating block and the second mating block are fixed together by several sets of clamping mechanisms.

6. The thermal insulation layer structure for tunnels in seasonally frozen soil areas according to claim 5, characterized in that: The clamping mechanism includes two sets of first fixing blocks, which are respectively fixedly connected to the first mating block and the second mating block. Each of the two sets of first fixing blocks is fixedly connected to a second fixing block. Both sets of first fixing blocks are inserted into a fixing sleeve. The two sets of second fixing blocks are engaged within the fixing sleeve. A second movable block is provided on the fixing sleeve, and a first limiting block is provided on the second movable block. A first limiting groove is provided on the fixing sleeve, and the first limiting block is slidably engaged within the first limiting groove. One side of the second movable block contacts the second mating block. A rubber block is fixedly connected to the fixing sleeve, and both sides of the rubber block contact the fixing sleeve and the second movable block, respectively. A first rectangular block is provided at one end of the rubber block, and a rectangular groove is provided on the fixing sleeve, where the first rectangular block is engaged.

7. The thermal insulation layer structure for tunnels in seasonally frozen soil areas according to claim 6, characterized in that: Both the connecting sleeve and the third connecting block have locking holes, and locking pins are inserted into the two sets of locking holes.

8. The thermal insulation layer structure for tunnels in seasonally frozen soil areas according to claim 7, characterized in that: The external insulation layer is located between the tunnel opening and the gravel layer, or between the gravel layer and the clay waterproof layer, or between the clay waterproof layer and the planting soil layer, or above the planting soil layer.

9. A method for constructing a tunnel insulation layer in seasonally frozen soil areas, comprising: S1: First, lay an inner insulation layer on the inner wall of the tunnel opening, then put the connecting sleeve on the third connecting block, and then use a pin to fix the connecting sleeve to the third connecting block, so that the telescopic rod is fixed to the tunnel opening; S2: Adjust the length of the two sets of telescopic rods so that the top of the movable rod is at the specified height. Then rotate the two sets of telescopic rods to a specified angle with the bottom surface. The connecting ring and the first spring increase the friction between the fixed rod and the connecting sleeve, ensuring that the telescopic rod will not rotate on the connecting sleeve without being affected by external force. S3: Backfilling and laying of the outer insulation layer: Backfill the gravel layer, clay waterproof layer and planting soil layer in the order from bottom to top. When the backfilling reaches the position of laying the outer insulation layer, stop backfilling and lay the outer insulation layer. At the same time, move the first mating block between the two sets of telescopic rods, then rotate the movable rod and then insert the movable rod into the hinge block so that the movable rod is hinged to the first mating block. S4: Lay the insulation material inside the first mating block, then move the second mating block above the first mating block and align the limiting block with the limiting groove, then move the second mating block downwards and clamp the second mating block onto the first mating block so that the two sets of first fixing blocks come into contact. S5: Place the fixing sleeve on the two sets of first blocks, then rotate the fixing sleeve, then move the second movable block to make the second movable block contact the second mating block, then move the rubber block to clamp the first rectangular block into the rectangular groove, fix the second movable block, the second movable block cooperates with the second fixing block to fix the fixing sleeve on the two sets of first fixing blocks, and then continue backfilling.

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