A method for constructing a submarine tunnel

Abstract

The invention belongs to the technical field of tunnel construction, and discloses a method for constructing a submarine tunnel. A first grouting liquid is used for splitting grouting to form slurry skeleton cracks in the soil of a weathering trough section to be excavated, and a second grouting liquid is used for infiltration grouting to fill the slurry skeleton cracks formed by the splitting grouting. The second grouting liquid with reduced permeability due to the addition of polypropylene crude fibers is consolidated in the slurry skeleton cracks to form a skeleton structure, which can effectively support the weathering trough section. The first grouting liquid with better permeability due to the addition of no polypropylene crude fibers is infiltrated into the slurry skeleton cracks and then consolidated, which can effectively block the fine gaps of the weathering trough section near the skeleton structure, thereby further reducing the compressibility and permeability coefficient of the weathering trough section. The second grouting pressure is less than the first grouting pressure, which avoids the continued generation of cracks at the tail end of the slurry skeleton cracks during the infiltration grouting, and ensures the filling effect of the first grouting liquid on the fine gaps around the slurry skeleton cracks.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a submarine tunnel construction method. Background Art

[0002] With the rapid development of modern transportation construction, the construction of undersea tunnels has solved the problem of transportation connection across straits, bays, and islands. The huge economic and social benefits it has generated have gradually entered the public eye. However, due to the complex geological and marine environment in which it is located, the construction and maintenance of undersea tunnels are also very obvious difficulties. The prevention and control of seawater infiltration and the earthquake resistance of tunnel structures are the two main technical problems to be solved in the project. Compared with other rock underground projects, undersea tunnels have the following engineering characteristics: (1) They have continuous high water pressure. The groundwater level is the sea level, which is much higher than the rock surface. It has a continuous and stable water pressure, and the replenishment of seawater is infinite, which makes seepage a serious problem. (2) The geological conditions are complex. Although most undersea tunnels are built in hard rock, they often encounter weathering troughs in the bedrock at the bottom of the fjord due to crossing the fjord. The rock mass in the weathering trough is severely weathered, weak and broken, with developed joints and fissures, low strength, high water content, no self-stabilization ability or poor self-stabilization ability. During excavation, water gushing, mud bursting and collapse are prone to occur, making it difficult to ensure construction safety and construction quality.

[0003] Therefore, there is an urgent need for a submarine tunnel construction method to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a submarine tunnel construction method, which can stably support the weathered trough section to be excavated, reduce the permeability coefficient of the weathered trough section to be excavated, effectively ensure the safety of subsequent construction, improve the stability of the tunnel, and reduce the leakage problem of the subsequent tunnel.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A subsea tunnel construction method comprises the following steps:

[0007] S1, splitting grouting, using a first grouting pressure to inject a first grouting liquid into the weathered trough section to be excavated in front of the tunnel face, so that the first grouting liquid splits the soil of the weathered trough section to be excavated to form grout vein skeleton cracks, and the radial extension range of the grout vein skeleton cracks is larger than the radial excavation range of the tunnel;

[0008] S2. Infiltration grouting: using a second grouting pressure to inject a second grouting liquid into the slurry vein skeleton fissures filled with the first grouting liquid, so that the first grouting liquid in the slurry vein skeleton fissures penetrates into the surrounding area of ​​the slurry vein skeleton fissures, and the second grouting liquid fills the slurry vein skeleton fissures. The second grouting pressure is less than the first grouting pressure. The preparation materials of the first grouting liquid and the second grouting liquid both include component A, and the preparation materials of the second grouting liquid also include polypropylene coarse fiber. The first grouting liquid and the second grouting liquid can both be consolidated to form a consolidated body.

[0009] Preferably, the splitting grouting specifically comprises the following steps:

[0010] S11, arranging a plurality of first grouting holes at intervals on the edge of the tunnel face, arranging a plurality of second grouting holes at intervals on the edge of the top arch of the excavated part of the tunnel close to the tunnel face, the second grouting holes extending in a direction close to the weathering trough section to be excavated;

[0011] S12, installing a first orifice pipe in the first grouting hole, wherein a portion of the first orifice pipe is exposed outside the first grouting hole, and installing a second orifice pipe in the second grouting hole, wherein a portion of the second orifice pipe is exposed outside the second grouting hole;

[0012] S13, using the grouting equipment to adopt the first grouting pressure to inject the first grouting liquid into the first grouting hole through the first orifice tube, and inject the first grouting liquid into the second grouting hole through the second orifice tube.

[0013] Preferably, the stopping condition of the splitting grouting is that the slurry flow rate of the grouting equipment drops below a first preset flow rate.

[0014] Preferably, the infiltration grouting specifically includes:

[0015] The second grouting liquid is injected into the first grouting hole through the first orifice pipe using the grouting equipment and the second grouting liquid is injected into the second grouting hole through the second orifice pipe using the second grouting pressure.

[0016] Preferably, the condition for stopping the injection of the second grouting liquid is that the slurry flow rate of the grouting equipment is less than the second preset flow rate and lasts for a preset time.

[0017] Preferably, along the extension direction of the tunnel, the first grouting hole extends in a direction away from the range of the tunnel to be excavated, and the second grouting hole is arranged perpendicular to the extension direction of the tunnel.

[0018] Preferably, the component A comprises component A1 and component A2;

[0019] The preparation materials of the component A1 include the following components in parts by weight: 40-60 parts of hydrophilic low-viscosity polyester polyol, 35-55 parts of penetrating diluent, 0.5-5 parts of surfactant, and 0.1-2 parts of catalyst;

[0020] The preparation materials of the component A2 include the following components in parts by weight: 50 to 85 parts of isocyanate, 5 to 30 parts of penetrating diluent, and 5 to 35 parts of flame retardant.

[0021] Preferably, step S2 further includes step S3, excavating the weathering trough section to be excavated, and applying a supporting lining on the surface of the tunnel after excavation.

[0022] Preferably, the supporting lining comprises a primary lining applied on the surface of the tunnel, a shock-absorbing layer applied on the surface of the primary lining, and a secondary lining applied on the surface of the shock-absorbing layer.

[0023] Preferably, the shock-absorbing layer is a polymer spray coating, and the primary lining layer and the secondary lining layer are both concrete layers.

[0024] Beneficial effects of the present invention:

[0025] The invention provides a subsea tunnel construction method, which uses a first grouting liquid to split and grout to form slurry vein skeleton cracks in the soil of the weathered trough section to be excavated, and uses a second grouting liquid to perform infiltration grouting to fill the slurry vein skeleton cracks formed by the splitting and grouting. In the process of the first grouting liquid splitting the weathered trough section to be excavated to form the slurry vein skeleton cracks, the surrounding rock of the weathered trough section to be excavated is squeezed to increase the density of the surrounding rock of the weathered trough section to be excavated, thereby reducing the compressibility and permeability coefficient. The second grouting liquid with reduced permeability due to the addition of polypropylene crude fiber is consolidated in the slurry vein skeleton cracks to form a skeleton. The second grouting liquid with added polypropylene crude fiber has high strength after consolidation, which can effectively support the weathering trough section. The first grouting liquid without added polypropylene crude fiber but with better permeability penetrates into the cracks of the slurry skeleton and consolidates, which can effectively block the small gaps of the weathering trough section near the skeleton structure, thereby further reducing the compressibility and permeability coefficient of the weathering trough section. The second grouting pressure is less than the first grouting pressure, which avoids the tail end of the slurry skeleton cracks during the infiltration grouting, and ensures the filling effect of the first grouting liquid on the small gaps around the slurry skeleton cracks. The weathering trough section to be excavated after being reinforced by the first grouting liquid and the second grouting liquid has improved strength and stability, reduced permeability, and avoided water gushing, mud bursting and collapse during subsequent excavation, effectively ensuring the safety of subsequent construction, improving the stability of the tunnel, and avoiding seepage problems in subsequent tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a submarine tunnel construction method provided by an embodiment of the present invention;

[0027] Figure 2 It is a flow chart of splitting grouting of a submarine tunnel construction method provided by an embodiment of the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the tunnel after construction provided by an embodiment of the present invention.

[0029] In the figure:

[0030] 100. Tunnel;

[0031] 1. Cracks in the pulp vein skeleton;

[0032] 2. Support lining;

[0033] 21. Primary lining layer; 22. Shock-absorbing layer; 23. Secondary lining layer. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0038] like Figure 1 As shown, this embodiment provides a subsea tunnel construction method, comprising the following steps:

[0039] S1, splitting grouting, using a first grouting pressure to inject a first grouting liquid into the weathered trough section to be excavated in front of the face, so that the first grouting liquid splits the soil of the weathered trough section to be excavated to form a grouting skeleton fracture 1, and the radial extension range of the grouting skeleton fracture 1 is greater than the radial excavation range of the tunnel 100;

[0040] S2, infiltration grouting, using a second grouting pressure to inject the second grouting liquid into the slurry skeleton fissures 1 filled with the first grouting liquid for infiltration grouting, so that the first grouting liquid in the slurry skeleton fissures 1 penetrates into the surrounding area of ​​the slurry skeleton fissures 1, and the second grouting liquid fills the slurry skeleton fissures 1. The second grouting pressure is less than the first grouting pressure. The preparation materials of the first grouting liquid and the second grouting liquid both include component A, and the preparation materials of the second grouting liquid also include polypropylene crude fiber. The first grouting liquid and the second grouting liquid can both consolidate to form a consolidated body.

[0041] The submarine tunnel construction method provided in this embodiment uses a first grouting liquid to perform splitting grouting to form a slurry skeleton fissure 1 in the soil of the weathered trough section to be excavated, and uses a second grouting liquid to perform infiltration grouting to fill the slurry skeleton fissure 1 formed by the splitting grouting. In the process of splitting the weathered trough section to be excavated to form the slurry skeleton fissure 1, the first grouting liquid squeezes the surrounding rock of the weathered trough section to be excavated, thereby increasing the density of the surrounding rock of the weathered trough section to be excavated, thereby reducing the compressibility and permeability coefficient. The second grouting liquid with reduced permeability due to the addition of polypropylene crude fiber is consolidated in the slurry skeleton fissure 1 to form a skeleton. The second grouting liquid with added polypropylene coarse fiber has high strength after consolidation, which can effectively support the weathering trough section. The first grouting liquid without added polypropylene coarse fiber but with better permeability penetrates into the slurry skeleton fissure 1 and consolidates, which can effectively block the small gaps of the weathering trough section near the skeleton structure, thereby further reducing the compressibility and permeability coefficient of the weathering trough section. The second grouting pressure is less than the first grouting pressure, which avoids the continued generation of cracks at the tail end of the slurry skeleton fissure 1 during the infiltration grouting, and ensures the filling effect of the first grouting liquid on the small gaps around the slurry skeleton fissure 1. The weathering trough section to be excavated after being reinforced by the first grouting liquid and the second grouting liquid has improved strength and stability, reduced permeability, avoided water gushing, mud bursting and collapse during subsequent excavation, effectively ensured the safety of subsequent construction, improved the stability of the tunnel, and avoided seepage problems in the subsequent tunnel 100.

[0042] Optionally, the first grouting pressure is 25MPa to 30MPa, and the second grouting pressure is 20MPa to 25MPa. During construction, the specific values ​​of the first grouting pressure and the second grouting pressure are determined according to the specific geological conditions of the weathering trough section to be excavated.

[0043] Alternatively, if Figure 2 As shown in FIG. 1 , the splitting grouting specifically includes the following steps:

[0044] S11, a plurality of first grouting holes are arranged at intervals on the edge of the tunnel face, and a plurality of second grouting holes are arranged at intervals on the edge of the top arch of the excavated part of the tunnel 100 close to the tunnel face, the second grouting holes extend in a direction close to the weathered trough section to be excavated, the grouting of the weathered trough section to be excavated mainly relies on the first grouting holes arranged on the tunnel face, and the second grouting holes mainly play a supporting role in the grouting of the excavated tunnel 100 section, while taking into account the grouting of the weathered trough section to be excavated;

[0045] S12, installing a first orifice pipe in the first grouting hole, with the first orifice pipe partially exposed outside the first grouting hole, and installing a second orifice pipe in the second grouting hole, with the second orifice pipe partially exposed outside the second grouting hole;

[0046] S13, using the grouting equipment to use the first grouting pressure to inject the first grouting liquid into the first grouting hole through the first orifice pipe, and inject the first grouting liquid into the second grouting hole through the second orifice pipe. Because the slurry diffuses to the surroundings, especially downward, under the action of gravity after being injected into the weathering trough section, it is necessary to give priority to the first grouting hole at the top of the tunnel and the second grouting hole at the top of the tunnel face for grouting operations according to actual conditions. After the splitting grouting and penetration grouting of the first grouting hole at the top of the tunnel and the second grouting hole at the top of the tunnel face are completed, the first grouting hole and the second grouting hole are grouted in turn from top to bottom.

[0047] Optionally, the stopping condition of the splitting grouting is that the slurry flow rate of the grouting equipment drops below a first preset flow rate. When the slurry flow rate is less than the first preset flow rate, it means that the splitting speed has been significantly reduced, and the significant reduction in the splitting speed indicates that the density of the surrounding rock of the nearby weathering trough section to be excavated has met the requirements.

[0048] Optionally, the infiltration grouting specifically includes: using a grouting device to use a second grouting pressure to inject a second grouting liquid into the first grouting hole through the first orifice pipe, and injecting the second grouting liquid into the second grouting hole through the second orifice pipe. Specifically, in this embodiment, the preset time is 10 minutes. Through long-term low-pressure infiltration grouting, the first grouting liquid in the slurry skeleton fissure 1 fully penetrates into the nearby small gaps, and the second grouting liquid fills the slurry skeleton fissure 1.

[0049] Optionally, the condition for stopping the injection of the second grouting liquid is that the slurry flow rate is less than the second flow rate and lasts for a preset time.

[0050] Optionally, along the extension direction of the tunnel 100, the first grouting hole extends in a direction away from the range to be excavated of the tunnel 100, and the second grouting hole is arranged perpendicular to the extension direction of the tunnel 100. The second grouting hole is arranged perpendicular to the extension direction of the tunnel 100, which can increase the extension range of the grout skeleton crack 1 and improve the supporting effect of the skeleton structure.

[0051] Optionally, component A includes component A1 and component A2. The preparation materials of component A1 include the following components in parts by weight: 40 to 60 parts of hydrophilic low-viscosity polyester polyol, 35 to 55 parts of penetrating diluent, 0.5 to 5 parts of surfactant, and 0.1 to 2 parts of catalyst. The preparation materials of component A2 include the following components in parts by weight: 50 to 85 parts of isocyanate, 5 to 30 parts of penetrating diluent, and 5 to 35 parts of flame retardant. When in use, component A1 and component A2 are mixed with water to form a first grouting liquid, and component A1, component A2 and polypropylene crude fiber are mixed to form a second grouting liquid. The penetrating diluent is respectively combined with the hydrophilic low-viscosity polyether polyol in component A1 and the isocyanate in component A2, thereby reducing the viscosity of the polymer material formed after mixing component A1 and component A2, improving the permeability, enhancing the consolidation effect between the polymer and the soil, and maintaining chemical stability for a long time. Therefore, by adjusting the weight fraction of the penetrating diluent in the first grouting liquid and the second grouting liquid preparation materials, the permeability of the first grouting liquid and the second grouting liquid can be adjusted. Preferably, the weight fraction of the penetrating diluent in the first grouting liquid preparation material should be greater than the weight fraction of the penetrating diluent in the second grouting liquid preparation material, thereby improving the permeability of the first grouting liquid and ensuring that the first grouting liquid can fully penetrate into the tiny gaps in the weathering trough section near the slurry skeleton cracks 1. The reaction time can be adjusted by adding a catalyst in a certain proportion. The weight percentage of the catalyst in the first grouting liquid preparation material should be less than the weight percentage of the catalyst in the second grouting liquid preparation material, so that the reaction time of the first grouting liquid is longer than that of the second grouting liquid, so as to match the grouting process of splitting grouting first and infiltration grouting later, which can ensure that the first grouting liquid will not solidify before the infiltration grouting is completed and affect the effect of the infiltration grouting, and ensure that the entire grouting process will not be too long. The strength of the solidified body formed by the first grouting liquid and the second grouting liquid will not only not decrease but will slowly increase under the erosion of water, and has extremely high durability. The solidified body also has the advantages of resistance to erosion by chloride salts and sulfates, and can improve the ability of the tunnel 100 to resist seawater corrosion.

[0052] Optionally, after step S2, step S3 is further included, excavating the weathered trough section to be excavated, and applying a supporting lining 2 on the surface of the tunnel 100 after excavation. After the supporting lining 2 is applied, the structure of the tunnel 100 is as follows: Figure 3 shown.

[0053] Optionally, the supporting lining 2 includes a primary lining 21 applied on the surface of the tunnel 100, a shock-absorbing layer 22 applied on the surface of the primary lining 21, and a secondary lining 23 applied on the surface of the shock-absorbing layer 22. Through the buffering and energy-absorbing effects of the shock-absorbing layer 22, the deformation and cracking of the supporting lining 2 when stress is concentrated are reduced, thereby reducing the seismic response of the tunnel 100 and improving the seismic resistance of the tunnel 100 structure.

[0054] Optionally, the shock-absorbing layer 22 is a polymer spray coating, and the primary lining layer 21 and the secondary lining layer 23 are both concrete layers. Specifically, in this embodiment, the thickness of the primary lining layer 21 is 25 cm, the thickness of the shock-absorbing layer 22 is 10 cm, and the thickness of the secondary lining layer 23 is 45 cm.

[0055] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for constructing a submarine tunnel, characterized in that: The steps include: S1, splitting grouting, using a first grouting pressure to inject a first grouting liquid into the weathered trough section to be excavated in front of the face, so that the first grouting liquid splits the soil of the weathered trough section to be excavated, forming a grout vein skeleton crack (1), and the radial extension range of the grout vein skeleton crack (1) is greater than the radial excavation range of the tunnel (100); S2, infiltration grouting, using a second grouting pressure to inject a second grouting liquid into the grouting skeleton fissure (1) filled with the first grouting liquid, so that the first grouting liquid in the grouting skeleton fissure (1) penetrates into the surrounding area of ​​the grouting skeleton fissure (1), and the second grouting liquid fills the grouting skeleton fissure (1), the second grouting pressure is less than the first grouting pressure, the preparation materials of the first grouting liquid and the second grouting liquid both include component A, the preparation materials of the second grouting liquid also include polypropylene coarse fiber, and the first grouting liquid and the second grouting liquid can both be consolidated to form a consolidated body; The splitting grouting specifically comprises the following steps: S11, arranging a plurality of first grouting holes at intervals on the edge of the tunnel face, arranging a plurality of second grouting holes at intervals on the edge of the top arch of the excavated portion of the tunnel (100) close to the tunnel face, the second grouting holes extending in a direction close to the weathering trough section to be excavated; S12, installing a first orifice pipe in the first grouting hole, wherein a portion of the first orifice pipe is exposed outside the first grouting hole, and installing a second orifice pipe in the second grouting hole, wherein a portion of the second orifice pipe is exposed outside the second grouting hole; S13, using a grouting device to inject the first grouting liquid into the first grouting hole through the first orifice pipe at the first grouting pressure, and injecting the first grouting liquid into the second grouting hole through the second orifice pipe; The component A comprises component A1 and component A2; The preparation materials of the component A1 include the following components in parts by weight: 40-60 parts of hydrophilic low-viscosity polyester polyol, 35-55 parts of penetrating diluent, 0.5-5 parts of surfactant, and 0.1-2 parts of catalyst; The preparation materials of the component A2 include the following components in parts by weight: 50-85 parts of isocyanate, 5-30 parts of penetrating diluent, and 5-35 parts of flame retardant.

2. The method for constructing a submarine tunnel according to claim 1, characterized in that: The stopping condition of the splitting grouting is that the slurry flow rate of the grouting equipment drops below a first preset flow rate.

3. The method for constructing a submarine tunnel according to claim 1, characterized in that: The infiltration grouting specifically comprises: The second grouting liquid is injected into the first grouting hole through the first orifice pipe using the grouting equipment and the second grouting liquid is injected into the second grouting hole through the second orifice pipe using the second grouting pressure.

4. The method for constructing a submarine tunnel according to claim 3, characterized in that: The condition for stopping the injection of the second grouting liquid is that the slurry discharge flow rate of the grouting equipment is less than the second preset flow rate and lasts for a preset time.

5. The method for constructing a submarine tunnel according to claim 1, characterized in that: Along the extension direction of the tunnel (100), the first grouting hole extends in a direction away from a range to be excavated of the tunnel (100), and the second grouting hole is arranged perpendicular to the extension direction of the tunnel (100).

6. The method for constructing a submarine tunnel according to claim 1, characterized in that: The method further comprises step S3 after step S2, excavating the weathered trough section to be excavated, and applying a supporting lining (2) on the surface of the tunnel (100) after excavation.

7. The method for constructing a submarine tunnel according to claim 6, characterized in that: The supporting lining (2) comprises a primary lining (21) applied on the surface of the tunnel (100), a shock absorbing layer (22) applied on the surface of the primary lining (21), and a secondary lining (23) applied on the surface of the shock absorbing layer (22).

8. The method for constructing a submarine tunnel according to claim 7, characterized in that: The shock-absorbing layer (22) is a polymer spray layer, and the primary lining layer (21) and the secondary lining layer (23) are both concrete layers.

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