Tunnel sealing composite flexible waterstop member and construction method thereof

Abstract

The invention discloses a tunnel plugging composite flexible waterstop component and its construction method in the technical field of water conservancy and hydropower engineering. The component comprises an expansion waterstop strip wrapped by a waterproof film, an expansion cement-based material, and a hose penetrating through the waterproof film and the expansion cement-based material and then extending into the expansion waterstop strip. During construction, the expansion cement-based material is located on the upstream and downstream sides of the expansion waterstop strip, the hose is extended to the outside of the plugging formwork and sealed, and the hose is opened after the plugging concrete construction is completed. The waterproof film can prevent the expansion waterstop strip from losing the waterstop effect due to the early expansion caused by the water in the cast concrete or underground water. Subsequently, the hose is used to introduce external water into the expansion waterstop strip, so that the expansion waterstop strip expands first, fills the gap, and achieves the waterstop effect. Then, the expansion cement-based material expands and hardens again, which can reduce the water head acting on the expansion waterstop strip and squeeze the closed hose to avoid the expansion waterstop strip being soaked in water for a long time, thereby improving the durability of the waterstop component.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and in particular to a composite flexible water-stopping component for tunnel sealing and its construction method. Background Technology

[0002] Tunnel sealing is a crucial step in preventing water seepage and ensuring structural safety in water conservancy, hydropower, transportation, and energy projects. From a construction perspective, the rock surface after tunnel excavation is often uneven, with irregular gaps and depressions. These gaps are particularly difficult to completely fill with concrete at the tunnel ceiling, resulting in cavities. Insufficient compaction during concrete pouring can leave air pockets and voids, especially at the ceiling. Poor sealing at the joints of end formwork or supports can lead to grout leakage and localized voids. From a concrete material perspective, the weight of the concrete after pouring causes it to flow and compact downwards, making it difficult for the material at the ceiling to remain in place, thus creating cavities. Hardened concrete undergoes drying shrinkage or creep, especially at the ceiling where restraint is minimal, making it prone to forming cracks in the surrounding rock. Therefore, the tunnel ceiling is a weak point in seepage prevention.

[0003] To ensure the sealing effect, especially for tunnel sealing that needs to retain water, water-stopping facilities are installed around the sealing concrete along the contour of the surrounding rock. The form of these facilities must be selected comprehensively based on the tunnel's function (such as water conveyance, power generation, or diversion), geological conditions (lithology, permeability), water head pressure, and operational requirements.

[0004] Currently, tunnel sealing and waterproofing structures mostly use rubber waterstops or metal waterstops, which are fixedly installed around the surrounding rock. Some structures also use auxiliary materials such as waterstop strips and sealants to enhance the seepage prevention effect. Because these waterproofing structures have relatively poor flexibility and cannot effectively and tightly adhere to the tunnel surrounding rock, they are usually fixed using waterstop grooves or waterstop spurs. Waterstop grooves are rectangular or trapezoidal grooves excavated circumferentially in the tunnel surrounding rock. Waterstop structures are then embedded inside the grooves and backfilled with pre-shrink mortar or similar backfill material. Waterstop spurs are circumferential spur-shaped structures directly arranged on the tunnel surrounding rock. Waterstops are pre-embedded inside the spurs, and mortar anchors are typically used to ensure effective fixation between the spurs and the surrounding rock. Pre-shrink mortar is generally used as the backfill material for the spurs.

[0005] In water-stopping structures using rubber waterstops and metal waterstops, the waterstop groove is small in size, making it difficult to form using blasting methods. Manual excavation is often used, which is difficult, inefficient, time-consuming, and involves high investment. Furthermore, the backfill material construction process is complex, especially at the arch, where quality is difficult to guarantee and construction risks are high. The waterstop stalk construction process is also complex, requiring layered laying and compaction of the backfill material, resulting in slow construction and a long construction period. Similarly, quality is difficult to guarantee at the arch, leading to high construction risks. Regardless of whether it's a waterstop groove or a waterstop stalk, the bond between the backfill material and the tunnel surrounding rock is crucial for the water-stopping effect, and both are subject to the aforementioned risks of cracking due to construction and material issues.

[0006] Waterstop strips are typically suitable for low water head conditions, but they are easily crushed under high water pressure. Waterstop strips cannot effectively control immersion time; in tunnels with well-developed groundwater, the waterstop strips will expand prematurely, losing their sealing effect. Before the concrete sealing the tunnel hardens and shrinks, the moisture in the concrete itself will cause the waterstop strips to expand prematurely, significantly reducing their sealing effectiveness. Furthermore, the durability of waterstop strips is only a few years, which is much shorter than the service life of tunnel sealing (up to 150 years in hydroelectric projects). Under high-pressure water or even corrosive water, their durability will be further reduced. Summary of the Invention

[0007] To overcome the aforementioned shortcomings of existing tunnel sealing and water-stopping structures, the technical problem to be solved by this invention is to provide a composite flexible water-stopping component for tunnel sealing that can adapt to uneven tunnel excavation surfaces, control the time for water-stopping to take effect, ensure water-stopping durability, improve water-stopping applicability and construction efficiency, and its construction method.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A composite flexible water-stopping component for tunnel sealing includes an expansion water-stop strip, an expansion cement-based material, a waterproof membrane, and a hose. The expansion cement-based material is disposed on both sides of the expansion water-stop strip and is sealed together by the waterproof membrane. One end of the hose passes through the waterproof membrane and the expansion cement-based material on one side and then extends into the middle of the expansion water-stop strip. The other end is a free end. The contact points between the outer wall of the hose and the surface of the expansion water-stop strip and the waterproof membrane are sealed with sealant.

[0010] Furthermore, the expansion sealing strip is a rubber-based, bentonite-based, or polyurethane-based expansion sealing strip.

[0011] Furthermore, the hose comprises multiple hoses, which are spaced apart along the length of the expansion seal strip.

[0012] Furthermore, the inner diameter of the hose is 3-10mm, and the distance between two adjacent hoses is 0.2-0.5m.

[0013] Furthermore, the waterproof membrane is a PVC membrane, PE membrane, HDPE composite membrane, TPU membrane, PU membrane, or geotextile; the hose is a flexible plastic or rubber hose.

[0014] A construction method for a composite flexible waterstop component for tunnel sealing involves using the aforementioned composite flexible waterstop component. First, the composite flexible waterstop component is fixed to the surrounding rock of the tunnel, ensuring that the expansion waterstop strip is tightly attached to the surrounding rock. The expansion cement-based materials on both sides face the upstream and downstream directions of the tunnel, respectively. Then, the flexible hose extends along the surrounding rock of the tunnel upstream to the outside of the sealing template and is sealed. Finally, after the backfilling of the sealing concrete is completed and the final setting temperature of the concrete reaches a stable temperature, or before the water is blocked in the tunnel sealing section, the seal of the flexible hose is opened, allowing the expansion waterstop strip to connect to the tunnel through the flexible hose.

[0015] Furthermore, before installing the tunnel sealing composite flexible water-stop component, a leveling base layer is first set on the surrounding rock of the tunnel, and then the tunnel sealing composite flexible water-stop component is fixed on the leveling base layer.

[0016] Furthermore, the leveling base layer is made of pre-shrink mortar, cement mortar or epoxy mortar. Both the leveling base layer and the tunnel sealing composite flexible water-stop component are set around the surrounding rock of the tunnel, and the width of the leveling base layer is greater than the width of the tunnel sealing composite flexible water-stop component.

[0017] Furthermore, the tunnel sealing composite flexible water-stop component is fixed to the leveling base layer by adhesive bonding or nailing.

[0018] Furthermore, the hose is initially sealed using mechanical sealing, heat sealing, bending sealing, or tape sealing, and later the hose is cut along the front end of the sealing concrete to open the hose channel.

[0019] The beneficial effects of this invention are:

[0020] 1. This invention combines an expansion waterstop strip with an expansion cement-based material, which can effectively adapt to the uneven rock surface formed by tunnel excavation and fill the gaps, especially the weak parts of the tunnel roof, thereby ensuring the water-stopping effect and greatly reducing the risk of seepage.

[0021] 2. The installation of the composite flexible water-stop component of the present invention does not require excavation of the surrounding rock to set water-stop grooves or water-stop spurs. It can be directly fixed to the surface of the surrounding rock by pasting or nailing, without causing damage to the surrounding rock structure. Moreover, the construction is simple and more efficient.

[0022] 3. This invention uses a waterproof membrane and a flexible hose to control the time it takes for the water-stopping strip to take effect, thus avoiding premature expansion of the water-stopping strip due to moisture in the poured concrete or groundwater, which would cause it to lose its water-stopping effect and effectively ensure the quality of the water-stopping.

[0023] 4. The expansive cement-based material used in this invention can not only assist in seepage prevention, but also reduce the water head acting on the expansive waterstop strip. At the same time, the expansive cement-based material can seal the flexible hose after expansion, preventing the expansive waterstop strip from being immersed in water for a long time, which greatly improves the durability of the composite flexible waterstop component. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the composite flexible waterstop component for tunnel sealing according to the present invention;

[0025] Figure 2 This is a radial view of the installation of the composite flexible water-stopping component for tunnel sealing according to the present invention;

[0026] Figure 3 This is an axial view of the installation of the composite flexible water-stopping component for tunnel sealing according to the present invention.

[0027] The markings in the diagram are as follows: 1-Expansion waterstop strip, 2-Expansion cement-based material, 3-Waterproof membrane, 4-Hose, 5-Tunnel surrounding rock, 6-Sealing concrete, 7-Leveling base layer, 8-Sealant. Detailed Implementation

[0028] The invention will be further described below with reference to the accompanying drawings.

[0029] It should be noted that if this invention uses directional terms such as up, down, left, right, front, and back, these are for describing the relative positions of components and are not specific references to the absolute positions of related components or the relationships between them. They are only used to explain the relative positional relationships and movements of components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. If this invention uses terms related to quantity such as "many," "multiple," or "several," these specifically refer to two or more.

[0030] like Figure 1As shown, the present invention provides a composite flexible water-stopping component for tunnel sealing, comprising an expandable water-stopping strip 1, an expandable cement-based material 2, a waterproof membrane 3, and a flexible hose 4. The expandable cement-based material 2 is disposed on both sides of the expandable water-stopping strip 1 and is sealed together by the waterproof membrane 3. One end of the flexible hose 4 passes through the waterproof membrane 3 and one side of the expandable cement-based material 2 and extends into the middle of the expandable water-stopping strip 1, while the other end is a free end. The contact points between the outer wall of the flexible hose 4 and the surface of the expandable water-stopping strip 1 and the waterproof membrane are sealed with sealant 8. The expandable water-stopping strip 1 is made of a material that can elastically expand after absorbing water. It can be made of rubber-based, bentonite-based, or polyurethane-based materials. After expansion, it can fill irregular voids in the surrounding rock of the tunnel, thereby achieving a water-stopping effect. The expandable cement-based material 2 refers to a material that can produce volume expansion during the hardening process after adding an expanding agent to an ordinary cement-based system. The expanding agent includes anhydrous tetracalcium aluminate sulfate, aluminum powder, aluminate slag, or calcium sulfate, etc. The waterproof membrane 3 can be made of PVC membrane, PE membrane, HDPE composite membrane, TPU membrane, PU membrane, or geotextile, as long as it can seal the internal expansion waterstop strip 1 and expansion cement-based material 2. The hose 4 is a flexible plastic or rubber hose, mainly used for water passage and air venting.

[0031] The working principle of the composite flexible waterstop component for tunnel sealing of the present invention is as follows: A waterproof film 3 is used to wrap the expansion waterstop strip 1 and the expansion cement-based material 2, which prevents the expansion waterstop strip 1 from expanding prematurely and losing its water-stopping effect due to moisture in the poured concrete or groundwater. After the concrete is poured, water is introduced into the expansion waterstop strip 1 through a hose 4, causing it to expand first, fill the gaps, and achieve a water-stopping effect. At the same time, the hose 4 is used to expel air from the gaps. After the expansion waterstop strip 1 has fully expanded, water will enter the expansion cement-based material 2 on both sides, causing it to expand as well. The expanded and hardened expansion cement-based material 2 reduces the water head acting on the expansion waterstop strip 1, and after expansion, it can compress and seal the hose 4, preventing the expansion waterstop strip 1 from being damaged by long-term immersion in water, thus greatly improving the durability of the composite flexible waterstop component.

[0032] In actual construction, the surfaces requiring sealing are generally quite long. Therefore, to ensure that the entire composite flexible waterstop component can absorb water and expand uniformly, multiple hoses 4 need to be installed, spaced apart along the length of the expansion waterstop strip 1. The specific parameters of the hoses 4 can be selected according to the actual project conditions, mainly including the inner and outer diameters and the spacing between them. The inner diameter of the hoses 4 mainly considers the smoothness of water flow and air venting, as well as whether the expanded cement-based material 2 can squeeze and seal the hoses 4 after expansion. The outer diameter or thickness of the hoses 4 mainly considers that they will not be squeezed and sealed by the concrete during concrete pouring. The spacing of the hoses 4 considers whether the expansion waterstop strip 1 can absorb water and expand uniformly. Based on the current requirements for tunnel plug waterstop structures in water conservancy projects and after extensive testing and verification, the preferred solution provided by this invention is that the inner diameter of the hoses 4 is 3-10mm, and the spacing between two adjacent hoses 4 is 0.2-0.5m. This ensures that the expansion waterstop strip 1 can expand uniformly, and that the expanded cement-based material 2, after expansion and curing, can squeeze and seal the hoses 4.

[0033] To facilitate construction by those skilled in the art, this invention also provides a construction method for a composite flexible waterstop component for tunnel sealing, comprising the following steps: First, the composite flexible waterstop component for tunnel sealing is fixed to the surrounding rock 5 of the tunnel, with the expansion waterstop strip 1 tightly attached to the surrounding rock 5, and the expansion cement-based material 2 on both sides facing the upstream and downstream directions of the tunnel, respectively. Then, the flexible hose 4 is extended along the surrounding rock 5 towards the outside of the sealing template and sealed. Finally, after the backfilling of the sealing concrete 6 is completed and the final setting temperature of the concrete reaches a stable temperature, or before the water is blocked in the tunnel sealing section, the seal of the flexible hose 4 is opened, allowing the expansion waterstop strip 1 to connect with the tunnel through the flexible hose 4. The formed structure is as follows. Figure 2 , Figure 3 As shown, the expansive cement-based material 2 is only placed on the upstream and downstream sides of the expansive waterstop strip 1, with its inner and outer sides directly contacting the sealing concrete 6 and the surrounding rock of the tunnel 5, so that the expansive waterstop strip 1 mainly expands inward and outward after absorbing water. Before pouring the sealing concrete 6, the hose 4 is sealed to prevent water from the tunnel from entering the expansive waterstop strip 1 and causing it to expand prematurely. After sealing is completed, the hose 4 is opened, and water from the tunnel enters the hose 4. Since the contact points between the hose 4 and the surface of the expansive waterstop strip 1 and the waterproof membrane 3 are sealed with sealant 8, external water preferentially enters the expansive waterstop strip 1 through the hose 4, causing it to expand upon contact with water, filling all irregular surfaces, cavities, and gaps at the joint, and generating huge contact pressure to achieve a water-stopping effect. After the expansive waterstop strip 1 expands, the water slowly penetrates into the expansive cement-based material 2 on both sides, causing it to harden upon contact with water. The expanded and hardened expanded cement-based material 2 can reduce the water head acting on the expanded waterstop strip 1, while squeezing the closed hose 4 to prevent the expanded waterstop strip 1 from being damaged by long-term immersion in water, thus greatly improving the durability of the composite flexible waterstop component.

[0034] In the specific construction process, the present invention also provides the following preferred solutions:

[0035] To minimize the impact of irregular surfaces on the surrounding rock 5 of the tunnel on the installation of the composite flexible waterstop component and its subsequent water-stopping effect, a leveling base layer 7 can be first installed on the surrounding rock 5 before installing the composite flexible waterstop component. The composite flexible waterstop component can then be fixed onto the leveling base layer 7. The leveling base layer 7 can be made of pre-shrink mortar, cement mortar, or epoxy mortar. During construction, its surface should be made as flat and smoothly transitioned as possible, and the width of the leveling base layer 7 should be greater than the width of the composite flexible waterstop component.

[0036] To ensure a good water-stopping effect throughout the entire perimeter of the sealing concrete 6, the leveling base layer 7 and the tunnel sealing composite flexible water-stop component should ideally both be arranged around the surrounding rock of the tunnel 5. The tunnel sealing composite flexible water-stop component can be fixed to the leveling base layer 7 by adhesive or nails during installation.

[0037] When arranging the hose 4, it can be fixed along the tunnel surrounding rock 5 using clamps or similar means. To prevent the hose 4 from being flattened during the pouring of the sealing concrete 6, a hose of appropriate thickness can be selected, or a steel pipe jacket can be added to the part passing through the sealing concrete 6. The hose 4 can be initially sealed using mechanical sealing, heat sealing, bending sealing, or tape sealing. Later, the hose 4 can be cut along the front end of the sealing concrete 6 to open the hose channel, so that water can flow through the opening of the hose 4 into the expansion sealing strip 1.

Claims

1. A composite flexible water-stopping component for tunnel sealing, characterized in that: The device includes an expansion waterstop strip (1), an expansion cement-based material (2), a waterproof membrane (3), and a hose (4). The expansion cement-based material (2) is placed on both sides of the expansion waterstop strip (1) and the two are sealed together by the waterproof membrane (3). One end of the hose (4) passes through the waterproof membrane (3) and the expansion cement-based material (2) on one side and then extends into the middle of the expansion waterstop strip (1). The other end is a free end. The outer wall of the hose (4) is sealed to the surface of the expansion waterstop strip (1) and the waterproof membrane at the contact point by the sealant (8).

2. The composite flexible water-stopping component for tunnel sealing as described in claim 1, characterized in that: The expansion waterstop strip (1) is a rubber-based, bentonite-based, or polyurethane-based expansion waterstop strip.

3. The composite flexible water-stopping component for tunnel sealing as described in claim 1, characterized in that: The hose (4) comprises multiple hoses, which are spaced apart along the length of the expansion seal strip (1).

4. The composite flexible water-stopping component for tunnel sealing as described in claim 3, characterized in that: The inner diameter of the hose (4) is 3-10mm, and the distance between two adjacent hoses (4) is 0.2-0.5m.

5. The composite flexible water-stopping component for tunnel sealing as described in claim 1, characterized in that: The waterproof membrane (3) is a PVC membrane, PE membrane, HDPE composite membrane, TPU membrane, PU membrane or geotextile; the hose (4) is a flexible plastic or rubber hose.

6. A construction method for a composite flexible water-stopping component for tunnel sealing, characterized in that: Using the tunnel sealing composite flexible water-stop component as described in any one of claims 1-5, first fix the tunnel sealing composite flexible water-stop component on the surrounding rock (5) of the tunnel, so that the expansion water-stop strip (1) is tightly attached to the surrounding rock (5) of the tunnel, and the expansion cement-based material (2) on both sides faces the upstream and downstream directions of the tunnel, then extend the hose (4) along the surrounding rock (5) of the tunnel to the outside of the sealing template and seal it. Finally, after the backfilling of the sealing concrete (6) is completed and the final setting temperature of the concrete reaches a stable temperature, or before the water is blocked in the tunnel sealing section, open the seal of the hose (4) so ​​that the expansion water-stop strip (1) is connected to the tunnel through the hose (4).

7. The construction method of a composite flexible water-stopping component for tunnel sealing as described in claim 6, characterized in that: Before installing the tunnel sealing composite flexible water-stop component, a leveling base layer (7) is first set on the surrounding rock (5) of the tunnel, and then the tunnel sealing composite flexible water-stop component is fixed on the leveling base layer (7).

8. The construction method of a composite flexible water-stopping component for tunnel sealing as described in claim 7, characterized in that: The leveling base layer (7) is made of pre-shrink mortar, cement mortar or epoxy mortar. The leveling base layer (7) and the tunnel sealing composite flexible water-stop component are both set around the surrounding rock (5) of the tunnel, and the width of the leveling base layer (7) is greater than the width of the tunnel sealing composite flexible water-stop component.

9. The construction method of a composite flexible water-stopping component for tunnel sealing as described in claim 8, characterized in that: The tunnel sealing composite flexible water-stop component is fixed to the leveling base layer (7) by adhesive bonding or nailing.

10. The construction method of a composite flexible water-stopping component for tunnel sealing as described in claim 6, characterized in that: The hose (4) is initially sealed by mechanical sealing, heat sealing, bending sealing or tape sealing, and later the hose (4) is cut off along the front end of the sealing concrete (6) to open the hose channel.

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