Composite seepage control structure and method for non-draining tunnel section of tunnel with water head of 50m or more

Abstract

This invention discloses a composite seepage control structure and method for non-drainage sections of tunnels with a head of 50m or more, comprising: an external surrounding rock structure, a consolidation grouting ring, a pressure-bearing lining, transverse drainage components, and a longitudinal pipe assembly; a pressure-bearing lining with a thickness of 40cm or more is installed on the inner wall of the tunnel; the external surrounding rock structure is located outside the pressure-bearing lining; and the consolidation grouting ring is installed outside the external surrounding rock structure. By setting different seepage-proof consolidation grouting rings outside the lining according to the magnitude of the external water load, the drainage volume and external water load are reduced, thereby achieving the purpose of reducing the external water load acting on the tunnel lining structure and avoiding water pollution caused by external water seepage.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a composite seepage control structure and method suitable for non-drainage tunnel sections of tunnels with a water head of 50m or more. Background Technology

[0002] Due to the complex geological structure along the water diversion project route, with some areas featuring well-developed faults and folds, and widespread karst formations, the tunnel construction environment experiences high external water pressure. Inadequate tunnel drainage solutions in these areas can lead to the leakage and loss of water sources crucial for local residents' livelihoods, posing safety hazards to the project. Therefore, ensuring the safety of the tunnel lining structure under high external water pressure during project operation is a critical technical issue that urgently needs to be addressed.

[0003] For tunnels with high external water pressure, the traditional approach is to "block" them by thickening the surrounding rock lining to improve tunnel stability. When the external water pressure is low, thickening the surrounding rock lining under the existing structure can meet the pressure requirements of the external water pressure and achieve tunnel stability.

[0004] For areas with external water pressure exceeding 1.5 MPa, the excessive external water pressure often necessitates the installation of concrete linings with thicknesses far exceeding those specified in water conservancy and hydropower engineering standards. The large volume of concrete required to increase the thickness generates heat during construction, leading to cracks in the lining and endangering the operational safety of the building. Furthermore, thickening the lining structure on the existing structure to resist external water pressure results in high construction costs. Summary of the Invention

[0005] This invention addresses the shortcomings of existing surrounding rock lining structures, such as huge investment, economic inefficiency, and poor structural stability, by providing a composite seepage control structure and method suitable for non-drained tunnel sections with water heads above 50m.

[0006] This invention provides a composite seepage control structure suitable for tunnel sections without drainage head of 50m or more, comprising: external surrounding rock structure, consolidation grouting ring, pressure-bearing lining, transverse drainage components and longitudinal pipe assembly;

[0007] The inner wall of the tunnel is equipped with a pressure-bearing lining with a thickness of more than 40cm; the external surrounding rock structure is set outside the pressure-bearing lining; and a consolidation grouting ring is set outside the external surrounding rock structure.

[0008] A transverse drainage component and a longitudinal pipe assembly are sandwiched between the consolidation grouting ring and the top arch of the pressure-bearing lining; each transverse drainage component is connected to the longitudinal pipe assembly; the outlet of the longitudinal pipe assembly is located outside the tunnel.

[0009] Multiple grouting holes are opened outward in a radial pattern from the tunnel within the consolidation grouting ring.

[0010] For tunnel sections with external water pressure P ≥ 1.5 MPa: full-section consolidation grouting is adopted, with grouting holes having a diameter of φ50; grouting hole depth L = 10m; grouting hole spacing 1.25m; grouting hole row spacing 2.5m;

[0011] For tunnel sections with external water pressure P ≥ 0.5 MPa, the permeability after grouting is 1 Lu to 3 Lu.

[0012] The consolidation grouting material used in the consolidation grouting ring is ordinary Portland cement; the grout concentration is gradually increased from 2:1 to 0.5:1; and the grouting pressure is 1 to 2 times the groundwater pressure.

[0013] Preferably, it includes: multiple capillary drainage strips and longitudinal drainage pipes; the capillary drainage strips and longitudinal drainage pipes are sandwiched between the consolidated grouting ring and the pressure-bearing lining.

[0014] Preferably, the capillary drainage belt is installed at 180° above the top arch along the transverse direction of the tunnel;

[0015] The longitudinal spacing between adjacent capillary drainage strips is 3m;

[0016] Each capillary drainage band is connected to a longitudinal drainage pipe;

[0017] The longitudinal drainage pipes are symmetrically arranged on both opposite sides of the tunnel and extend longitudinally along the tunnel; the longitudinal drainage pipes lead to the discharge outlets at the tunnel entrance / exit or branch tunnel entrance.

[0018] Preferably, the pressure-bearing lining includes: multiple concrete linings, a waterproof membrane, and a non-woven geotextile; a water-curing polyurethane waterproof coating is applied to the outer wall of the concrete lining; a waterproof membrane is laid on the concrete lining facing outwards from the tunnel; and a non-woven geotextile is applied to the outside of the waterproof membrane.

[0019] Preferably, in tunnel sections where the external water pressure P < 0.5 MPa, the rock mass wave velocity increase rate after grouting is not less than 20%.

[0020] Preferably, for tunnel sections where the external water pressure P < 0.5 MPa: consolidation grouting is only performed on the top arch of the Class V external surrounding rock structure, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50 mm, a hole depth of L = 5 m, and a spacing of 3 m between rows.

[0021] Preferably, for tunnel sections with external water pressure of 0.5MPa≤P<1MPa: consolidation grouting is carried out on the entire cross section, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50mm, a hole depth of L=6m, a spacing of 2m, and a row spacing of 2.5m.

[0022] Preferably, for tunnel sections with external water pressure of 1MPa≤P<1.5Mpa: consolidation grouting is carried out on the entire cross section, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50mm, a hole depth of L=8m, a spacing of 1.5m, and a row spacing of 2.5m.

[0023] Another aspect of the present invention provides a seepage control method for non-drained tunnel sections of tunnels with water heads of 50m or more, comprising the following steps:

[0024] Step S1: Measure the external water head and external water pressure of the tunnel, install a pressure-bearing lining with a thickness of more than 40cm on the inner wall of the tunnel, and install an external surrounding rock structure on the outside of the pressure-bearing lining.

[0025] Step S2: Determine the consolidation grouting area of ​​the tunnel section based on the external water pressure. Within the consolidation grouting area, multiple grouting holes are opened radially outward from the tunnel as the starting point.

[0026] Step S3: After grouting along the grouting hole, a consolidation grouting ring is set on the outside of the external surrounding rock structure, and a transverse drainage component and a longitudinal pipe assembly are sandwiched between the pressure-bearing lining and the consolidation grouting ring.

[0027] For tunnel sections with external water pressure P ≥ 1.5 MPa: full-section consolidation grouting is adopted, with grouting holes having a diameter of φ50; grouting hole depth L = 10m; grouting hole spacing 1.25m; grouting hole row spacing 2.5m;

[0028] For tunnel sections with external water pressure P ≥ 0.5 MPa, the permeability after grouting is 1 Lu to 3 Lu.

[0029] The consolidation grouting material used in the consolidation grouting ring is ordinary Portland cement; the grout concentration is gradually increased from 2:1 to 0.5:1; and the grouting pressure is 1 to 2 times the groundwater pressure.

[0030] Preferably, in tunnel sections where the external water pressure P < 0.5 MPa, the increase in rock mass wave velocity after grouting is not less than 20%;

[0031] More preferably, in tunnel sections where the external water pressure P < 0.5 MPa, the increase rate of rock mass wave velocity after grouting is not less than 20%;

[0032] More preferably, for tunnel sections where the external water pressure P < 0.5 MPa: consolidation grouting is only carried out on the side arch of the Class V external surrounding rock structure, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50 mm, a hole depth of L = 5 m, and a spacing of 3 m between rows;

[0033] More preferably, for tunnel sections with external water pressure of 0.5MPa≤P<1MPa: consolidation grouting is carried out on the entire cross section, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50mm, a hole depth of L=6m, a spacing of 2m, and a row spacing of 2.5m;

[0034] More preferably, for tunnel sections with external water pressure of 1MPa≤P<1.5Mpa: consolidation grouting is carried out on the entire cross section, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50mm, a hole depth of L=8m, a spacing of 1.5m, and a row spacing of 2.5m.

[0035] The beneficial effects that this invention can produce include:

[0036] 1) The composite seepage control structure provided by this invention, applicable to tunnel sections with water heads greater than 50m, utilizes external surrounding rock, consolidation grouting rings, lining structures, and external drainage measures to achieve non-drainage for tunnel sections with external water heads greater than 50m.

[0037] In the water tunnel section, transverse and longitudinal drainage pipes are used to drain and relieve pressure in the arch between the lining and the seepage-proof consolidation grouting ring. Simultaneously, drainage is also carried out outside the lining according to...

[0038] Different anti-seepage consolidation grouting rings 11 are set according to the magnitude of external water load to reduce drainage and external water load. This achieves the purpose of reducing the external water load acting on the tunnel lining structure and avoiding water pollution caused by external water seepage.

[0039] 2) The composite seepage control structure provided by this invention, applicable to non-drained tunnel sections with water heads above 50m, is structurally stable, highly versatile, and has excellent drainage and waterproofing effects. It can effectively reduce the external water load acting on the tunnel lining structure and prevent water pollution caused by external water seepage, thereby improving tunnel safety during operation and ensuring water quality. It is an effective seepage control arrangement for non-drained tunnel sections where groundwater contains pollutants. Attached Figure Description

[0040] Figure 1 This is a cross-sectional schematic diagram of a composite seepage control type applicable to tunnel sections without drainage in an embodiment of the present invention with a water head of 50m or more. The diagram shows a horseshoe-shaped structure.

[0041] Figure 2 This is a schematic diagram of the cross-sectional structure of the lining structure of the composite seepage control structure for tunnel sections without drainage in accordance with water head above 50m, as described in this embodiment of the invention.

[0042] Legend:

[0043] 1. Grouting hole; 11. Consolidated grouting ring; 2. Longitudinal drainage pipe; 3. Capillary drainage strip; 4. Pressure-bearing lining; 5. External surrounding rock structure; 6. Water-cured polyurethane waterproof coating; 7. Waterproof membrane; 8. Buffer layer non-woven geotextile. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0046] Technical means not described in detail in this invention and not used to solve the technical problems of this invention are all set according to common knowledge in the field, and multiple common knowledge setting methods can be implemented.

[0047] See Figures 1-2 The composite seepage control structure provided by this invention, suitable for tunnel sections with water heads above 50m, integrates the external surrounding rock structure 5, the consolidation grouting ring 11, the lining structure, and the external drainage system.

[0048] The composite seepage control structure type for tunnel sections without drainage in the embodiment of the present invention, which is applicable to water heads of 50m or more, includes an external surrounding rock structure 5, consolidation grouting, and lining structure, with the external surrounding rock structure set at the bottom of the tunnel.

[0049] The lining structure of this invention adopts impermeable lining (the lining structure does not have drainage holes). Different anti-seepage consolidation grouting rings 111 are set according to the size of the external water load to reduce the external water load. At the same time, for tunnel sections with an external water head greater than 50m, the transverse and longitudinal drainage pipes 2 of the top arch between the lining and the anti-seepage consolidation grouting ring 11 are used to drain and relieve pressure.

[0050] For tunnel sections with external water head greater than 50m and poor drainage conditions, appropriate thickening of the lining structure should be adopted.

[0051] In one specific embodiment, the pressure-bearing lining 4 (with a horseshoe-shaped cross-section) provided by the present invention uses C30 W10 F150 concrete, and a water-curing polyurethane waterproof coating 6 is sprayed on the surface of the sprayed concrete. The inner surface of the concrete lining is coated with the water-curing polyurethane waterproof coating 6.

[0052] A waterproof membrane 7 is installed on the outer surface of the lining, and a buffer layer of non-woven geotextile 8 is laid on the outside of the waterproof membrane 7. Lining structural joints.

[0053] One copper waterstop and one rubber waterstop are required at each location, and the structural joints are filled with polysulfide sealant.

[0054] The consolidation grouting methods of this invention are classified according to the magnitude of external water pressure:

[0055] 1) For tunnel sections with external water pressure P < 0.5 MPa: only the five-sided arch of the Class V external surrounding rock structure is reinforced with grouting. The grouting hole diameter is φ50 mm, the hole depth is L = 5 m, and the spacing between rows is 3 m.

[0056] 2) For tunnel sections with external water pressure of 0.5MPa≤P<1MPa: the entire cross-section is grouted for consolidation. The grouting holes have a diameter of φ50mm, a depth of L=6m, a spacing of 2m, and a row spacing of 2.5m.

[0057] 3) For tunnel sections with external water pressure of 1MPa≤P<1.5Mpa: the entire cross-section is grouted for consolidation. The grouting holes have a diameter of φ50mm, a depth of L=8m, a spacing of 1.5m, and a row spacing of 2.5m.

[0058] 4) For tunnel sections with external water pressure P≥1.5MPa: the entire cross-section is grouted for consolidation. The grouting hole diameter is φ50mm, the hole depth is L=10m, the spacing is 1.25m, and the row spacing is 2.5m.

[0059] The consolidation grouting material of the present invention uses ordinary silicate cement, and the grout concentration is gradually controlled from 2:1 to 0.5:1. The grouting pressure is 1 to 2 times the groundwater pressure.

[0060] For tunnel sections with external water pressure P < 0.5 MPa, the increase in rock mass wave velocity after grouting should be no less than 20%. For tunnel sections with external water pressure P ≥ 0.5 MPa...

[0061] For a 0.5 MPa tunnel section, the permeability after irrigation is 1 Lu to 3 Lu.

[0062] The present invention provides transverse and longitudinal drainage and pressure relief in the arch between the pressure-bearing lining 4 and the seepage-proof consolidation grouting ring 11.

[0063] A capillary drainage strip 3 is installed laterally at the top arch 180, with a longitudinal drainage spacing of 3m. The capillary drainage strip 3 is connected to the longitudinal drainage pipe 2, and the longitudinal drainage pipe 2 discharges to the nearest tunnel entrance or exit or branch tunnel entrance.

[0064] First, the external water pressure is initially reduced by the external surrounding rock structure 5;

[0065] Subsequently, a consolidation grouting ring 11 is formed through the consolidation grouting hole 1 (distinguishing between external water head of 0.5MPa or more, 1.0 or more, and 1.5 or more) to bear the water head portion exceeding 50m, further reducing the external water pressure;

[0066] Secondly, a reinforced concrete lining with a thickness of more than 40cm is constructed to withstand external water head of 50m and below, and the lining is used to achieve structural self-waterproofing.

[0067] Finally, external drainage measures are added to discharge the infiltrated water containing pollutants to the tunnel entrance and exit through capillary drainage belt 3 and PVC drainage pipe, thereby reducing the external water load on the tunnel lining structure and preventing water pollution caused by external water infiltration.

[0068] This invention comprehensively utilizes measures such as external surrounding rock, consolidation grouting rings, lining structure, and external drainage. For non-drainage tunnel sections with an external water head greater than 50m, transverse and longitudinal drainage pipes are installed in the arch between the lining and the anti-seepage consolidation grouting ring to release pressure. At the same time, different anti-seepage consolidation grouting rings are set outside the lining according to the size of the external water load to reduce the drainage volume and external water load, thereby achieving the purpose of reducing the external water load acting on the tunnel lining structure and avoiding water pollution caused by external water seepage.

[0069] For tunnels under external water pressure, when the pressure is low, the surrounding rock lining is sufficient to withstand the pressure and stabilize the tunnel. However, for tunnels with high external water pressure, the concrete lining often needs to be installed to a thickness far exceeding that specified in the relevant specifications for water conservancy and hydropower projects. But this approach inevitably leads to cracks due to the heat generated during the construction of large volumes of concrete, which endangers the operational safety of the structure. At the same time, relying solely on the lining structure to resist external water pressure is not economically viable and lacks economic rationality.

[0070] This invention features a stable structure, strong versatility, and excellent drainage and waterproofing effects. It effectively reduces the external water load acting on the tunnel lining structure and prevents water pollution caused by external water seepage, thereby improving tunnel safety during operation and ensuring water quality. It is an effective seepage control arrangement suitable for non-drained tunnel sections where groundwater contains pollutants. Example

[0071] Unless otherwise specified, all materials used in the following embodiments were obtained through commercial channels; the following embodiments used [materials / treatments].

[0072] Unless otherwise specified, the construction and grouting methods are all commonly used methods in this field.

[0073] See Figures 1-2 This embodiment uses a horseshoe-shaped tunnel as an example for illustration. During construction, the external water head and external water pressure of the tunnel are first measured. The external water head of this section is 56.5m and the external water pressure is 1.85MPa. Based on these parameters, the seepage control structure is determined, including: external surrounding rock structure, consolidation grouting ring, pressure-bearing lining, transverse drainage components and longitudinal pipe assembly.

[0074] The inner wall of the tunnel section is equipped with a 48cm thick pressure-bearing lining; the pressure-bearing lining is made of reinforced concrete; the external surrounding rock structure is set outside the pressure-bearing lining; a consolidation grouting ring is set outside the external surrounding rock structure.

[0075] Based on the external water head and pressure of the tunnel, a consolidation grouting ring is to be installed throughout the entire tunnel cross-section. Grouting holes are to be drilled through the consolidation grouting ring, the pressure-bearing lining, and the external surrounding rock structure. These grouting holes are elongated, with multiple effluent outlets on their inner sides. The hole diameter is φ50mm; the hole depth L = 10m; the hole spacing is 1.25m; the row spacing is 2.5m; and the post-grouting permeability is 1Lu to 3Lu. The grout concentration is gradually increased from 2:1 to 0.5:1; the grouting pressure is twice the groundwater pressure.

[0076] Capillary drainage strips and longitudinal drainage pipes are sandwiched between the consolidated grouting ring and the pressure-bearing lining.

[0077] Capillary drainage belts are installed transversely along the tunnel at a position 180° above the top arch;

[0078] The longitudinal spacing between adjacent capillary drainage strips is 3m;

[0079] Each capillary drainage band is connected to a longitudinal drainage pipe;

[0080] The longitudinal drainage pipes are symmetrically installed on both opposite sides of the tunnel and extend longitudinally along the tunnel; the longitudinal drainage pipes lead to the discharge outlets at the tunnel entrance / exit or branch tunnel entrance.

[0081] The pressure-bearing lining includes: multiple concrete linings, a waterproof membrane, and a non-woven geotextile; a water-curing polyurethane waterproof coating is applied to the outer wall of the concrete lining; a waterproof membrane is laid on the side of the concrete lining facing outward from the tunnel; and a non-woven geotextile is applied to the outside of the waterproof membrane.

[0082] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A seepage control method applicable to non-drained tunnel sections of tunnels with water heads above 50m, characterized in that, Includes the following steps: Step S1: Measure the external water head and external water pressure of the tunnel, install a pressure-bearing lining with a thickness of more than 40cm on the inner wall of the tunnel, and install an external surrounding rock structure on the outside of the pressure-bearing lining. Step S2: Determine the consolidation grouting zone of the tunnel cross-section based on the external water pressure, and within the consolidation grouting zone, take the tunnel as the starting point. Multiple grouting holes are opened in a radial pattern, radiating outwards from the point. Step S3: After grouting along the grouting hole, a consolidation grouting ring is set on the outside of the external surrounding rock structure, and a transverse drainage component and a longitudinal pipe assembly are sandwiched between the pressure-bearing lining and the consolidation grouting ring. For tunnel sections with external water pressure P ≥ 1.5 MPa: full-section consolidation grouting is adopted, and the diameter of the grouting holes is φ50 mm; the depth of the grouting holes is L = 10 m; Grouting hole spacing: 1.25m; Grouting hole row spacing: 2.5m; For tunnel sections with external water pressure P ≥ 0.5 MPa, the permeability after grouting is 1 Lu to 3 Lu. The consolidation grouting material used in the consolidation grouting ring is ordinary Portland cement; the grout concentration is gradually increased from 2:1 to 0.5:1; the grouting pressure is 1 to 2 times the groundwater pressure. For tunnel sections with external water pressure P < 0.5 MPa, the increase in rock mass wave velocity after grouting shall not be less than 20%. For tunnel sections with external water pressure P < 0.5 MPa: consolidation grouting is only carried out on the side arch of the Class V external surrounding rock structure, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50 mm, a hole depth of L = 5 m, and a spacing of 3 m between rows; For tunnel sections with external water pressure of 0.5MPa≤P<1MPa: consolidation grouting is carried out on the entire cross section, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50mm, a hole depth of L=6m, a spacing of 2m, and a row spacing of 2.5m; For tunnel sections with external water pressure of 1MPa≤P<1.5MPa: consolidation grouting is carried out on the entire cross section, and a consolidation grouting ring is set up; the grouting holes opened in the consolidation grouting ring have a diameter of φ50mm, a hole depth of L=8m, a spacing of 1.5m, and a row spacing of 2.5m; The seepage control structure applicable to the non-drainage tunnel section of tunnels with a water head of 50m or more includes: external surrounding rock structure, consolidation grouting ring, pressure-bearing lining, transverse drainage components and longitudinal pipe assembly. The inner wall of the tunnel is equipped with a pressure-bearing lining with a thickness of more than 40cm; the external surrounding rock structure is set outside the pressure-bearing lining; and a consolidation grouting ring is set outside the external surrounding rock structure. A transverse drainage component and a longitudinal pipe assembly are sandwiched between the consolidation grouting ring and the top arch of the pressure-bearing lining; each transverse drainage component is connected to the longitudinal pipe assembly; the outlet of the longitudinal pipe assembly is located outside the tunnel. Multiple grouting holes are opened outward in a radial pattern from the tunnel within the consolidation grouting ring.

2. The seepage control method for tunnel sections without drainage in accordance with claim 1, characterized in that, include: Multiple capillary drainage strips and longitudinal drainage pipes are installed between the consolidated grouting ring and the pressure-bearing lining.

3. The seepage control method for tunnel sections without drainage in accordance with claim 2, applicable to water heads above 50m, is characterized by... It lies in, Capillary drainage belts extend laterally along the tunnel at the top arch, 180 degrees. o The capillary drainage belts are installed at a distance of 3m from each other. Each capillary drainage strip is connected to a longitudinal drainage pipe; The longitudinal drainage pipes are symmetrically arranged on both opposite sides of the tunnel and extend longitudinally along the tunnel; the longitudinal drainage pipes lead to the discharge outlets at the tunnel entrance / exit or branch tunnel entrance.

4. The seepage control method for tunnel sections without drainage in accordance with claim 1, applicable to water heads above 50m, is characterized in that, The pressure-bearing lining includes: multiple concrete linings, a waterproof membrane, and a non-woven geotextile; a water-curing polyurethane waterproof coating is applied to the outer wall of the concrete lining; a waterproof membrane is laid on the outside of the concrete lining facing the tunnel; and a non-woven geotextile is applied to the outside of the waterproof membrane.

Images