Tunnel intake structure for non-blasting construction under deep water conditions and its construction method

Abstract

The present invention discloses a tunnel inlet structure for non-blasting construction under deep water conditions. It includes a reinforced concrete structure located underwater and a tunnel inlet; the reinforced concrete structure includes inlet side walls, an inlet floor slab, and a concrete panel; the inlet side walls are respectively arranged on both sides of a construction shaft; the inlet floor slab is arranged at the bottom of the construction shaft; the concrete panel is arranged along the mountain slope at the downstream ends of the spaced inlet side walls; one end of the concrete panel is arranged at the connection between the tunnel inlet and the inlet side wall, and the other end extends upward out of the inlet side wall; the tunnel inlet is arranged at the lower part of the inlet side wall; the tunnel inlet is communicated with a trumpet-shaped structure formed by the reinforced concrete structure; a multi-functional vortex-eliminating beam is arranged between the two spaced inlet side walls. The present invention has the advantages of simple underwater construction, high safety, and low investment at the tunnel inlet. The present invention also discloses a construction method for the tunnel inlet structure for non-blasting construction under deep water conditions.

Description

Technical Field

[0001] The present invention relates to a structure and construction method of a tunnel water inlet arranged underwater. More specifically, it is a structure and construction method of a tunnel water inlet for non-explosive construction under deep water conditions, mainly applicable to tunnel construction where the water level during the construction period cannot be lowered below the elevation of the bottom plate of the tunnel inlet, and the excavation support and permanent structure of the inlet need to be carried out underwater. Background Art

[0002] When constructing a new tunnel water inlet in an existing reservoir or natural lake, it is usually necessary to lower the reservoir water level or build a temporary cofferdam at the inlet to block water to ensure dry construction. Since the new tunnel water inlet is located dozens of meters deep below the water surface, emptying or lowering the reservoir water level will bring great negative impacts and losses to society, economy, environment, ecology and tourism. If a deep-water cofferdam is built, due to the high cofferdam, large project volume, difficult anti-seepage treatment, and at the same time, problems such as silt cleaning, excavation, drainage and transportation of the foundation pit need to be considered, the construction is relatively complex and the construction period is long; after the water inlet is completed, the removal of the cofferdam is also relatively difficult and the project cost is high. In some projects (such as the case where the terrain of the tunnel inlet is relatively steep and the geological conditions are poor), due to factors such as terrain, geology and water depth, it is simply impossible to build a cofferdam, and the reservoir cannot be emptied or the water level cannot be lowered, so underwater construction has to be adopted.

[0003] At present, the underwater construction of tunnel inlets often adopts the rock plug blasting method, but the rock plug blasting has the following disadvantages: ① The design requirements for the rock plug are high. If the rock plug is too thick, it is difficult to blast through it at one time; if it is too thin, the structure is not safe. ② The blasting construction technology is difficult, the safety of the excavation chamber is poor, the rupture line of the blasting funnel is not easy to control, and the blasting vibration has a greater impact. ③ The project cost is high. ④ After the rock plug blasting, only the water inlet and the diversion tunnel are penetrated, and the water inlet structure is still rock, and no engineering measures are taken, there is a risk of the safety of the rock mass itself structure.

[0004] Therefore, it is very necessary to develop a structure and method of a tunnel water inlet for non-explosive construction under deep water conditions with small construction vibration impact, low project cost, high construction safety, and capable of directly carrying out underwater construction. Summary of the Invention

[0005] The first object of the present invention is to provide a structure of a tunnel water inlet for non-explosive construction under deep water conditions, with small construction vibration impact, low project cost, high construction safety, capable of directly carrying out underwater construction at the tunnel water inlet, simple construction, high safety, less investment, and does not require lowering the reservoir water level or building a temporary cofferdam at the inlet to block water during construction; it solves the defect that dry construction methods usually need to lower the reservoir water level or build a temporary cofferdam at the inlet to block water in the new tunnel water inlet; effectively solves the underwater construction of the new tunnel water inlet under deep water conditions and the complete set of technologies for the water inlet structure, and is especially applicable to the case where the terrain of the tunnel inlet is relatively steep and the geological conditions are poor.

[0006] The second object of the present invention is to provide a construction method for the tunnel intake structure constructed without blasting under deep water conditions. Through the underwater non-blasting construction technology, an underwater newly built tunnel intake structure is formed, which is applicable to the construction of newly built tunnels under deep water conditions.

[0007] In order to achieve the first object of the present invention, the technical solution of the present invention is: a tunnel intake structure constructed without blasting under deep water conditions, characterized in that: it is excavated and cast under deep water conditions; the tunnel intake structure constructed without blasting under deep water conditions is in a horn shape;

[0008] The tunnel intake structure constructed without blasting under deep water conditions includes a reinforced concrete structure located underwater and a tunnel inlet;

[0009] The reinforced concrete structure includes intake side walls, an intake bottom slab and a concrete panel;

[0010] The intake side walls are respectively arranged on both sides of the construction shaft;

[0011] The intake bottom slab is arranged at the bottom of the construction shaft and at the bottom of the intake side walls;

[0012] The concrete panel is arranged along the mountain slope at the downstream ends of the spaced intake side walls; one end of the concrete panel is arranged above the tunnel inlet and the other end extends upward beyond the intake side walls;

[0013] The tunnel inlet is arranged at the lower part of the intake side walls and at the outer lower end of the concrete panel;

[0014] The tunnel inlet is connected to the horn-shaped structure surrounded by the reinforced concrete structure;

[0015] The multi-functional vortex-eliminating beam is arranged between the two spaced intake side walls.

[0016] In the above technical solution, there are multiple rows of multi-functional vortex-eliminating beams, and the multiple rows of multi-functional vortex-eliminating beams are arranged at intervals along the longitudinal direction of the intake side walls;

[0017] Each row of multi-functional vortex-eliminating beams includes one or more multi-functional vortex-eliminating beams.

[0018] In the above technical solution, the intake side walls are in a right trapezoidal structure; the length of the upper end of the intake side walls is greater than the length of the lower end.

[0019] In the above technical solution, the bottom slab of the tunnel inlet is flush with the intake bottom slab.

[0020] In the above technical solution, a chute is arranged at the downstream end of the intake side walls; the chute is located at the connection between the intake side walls and the concrete panel;

[0021] The length of the chute is equal to the length of the downstream end of the intake sidewall;

[0022] The trash rack is arranged on the chute and is slidably connected to the chute.

[0023] In order to achieve the second object of the present invention, the technical solution of the present invention is: a construction method for a tunnel intake structure under non-explosive construction under deep water conditions, including the following steps,

[0024] Step 1: Excavate the tunnel inlet slope on the downstream side of the underwater reserved rock sill to form a construction platform; determine the excavation range of the construction shaft on the construction platform according to the dimensions of the tunnel intake structure;

[0025] Step 2: Conduct single-row or double-row curtain grouting around the construction shaft determined in Step 1 to form a closed curtain grouting structure;

[0026] Step 3: Excavate and support the construction shaft within the excavation range of the construction shaft determined in Step 1;

[0027] Before excavation, set a collar around the construction shaft; excavate the construction shaft in the order from top to bottom;

[0028] During the construction of the construction shaft, use systematic bolts and reinforced concrete primary lining for support;

[0029] Step 4: Construct the tunnel intake structure;

[0030] Pour the reinforced concrete structure in the construction shaft in the order from bottom to top and support it through systematic bolts and reinforced concrete primary lining;

[0031] Step 5: Excavate and line and support the tunnel inlet section;

[0032] Excavate the tunnel inlet section at the tunnel inlet and support it through lining;

[0033] Step 6: After the construction of the tunnel inlet section is completed, close the tunnel gate and fill and level the tunnel inlet;

[0034] Step 7: Cut off the steel bars of the initial support on the water-facing side of the construction shaft and open an opening on the upstream side of the curtain grouting structure so that the upstream water can pass through the curtain grouting structure and enter the tunnel intake structure under non-explosive construction under deep water conditions;

[0035] Select a long-arm excavator to demolish the underwater reserved rock sill according to the construction water depth.

[0036] In the above technical solution, in Step 1, the construction platform is above the water level, and the size of the construction platform meets the needs of the construction operation site.

[0037] The deep - water condition described in the present invention refers to that the intake of the newly - built tunnel is located dozens of meters deep below the water surface.

[0038] The present invention has the following advantages:

[0039] Aiming at the problem of difficult underwater construction at the tunnel intake, the present invention combines the permanent structure of the intake with the construction shaft. Before the excavation of the construction shaft, curtain grouting is adopted for seepage prevention treatment to reduce the seepage after the shaft excavation; during the shaft excavation process, the method of excavating and supporting simultaneously is adopted to effectively ensure the construction safety; a rock sill is reserved and non - blasting underwater excavation and removal are carried out after the completion of the permanent structure construction. This intake structure and construction method not only meet the requirements of underwater dry - land construction but also ensure the structural safety.

[0040] A tunnel intake structure and construction technical method proposed by the present invention is simple in construction, high in safety, less in investment, can effectively avoid a series of problems brought by blasting excavation, and provides a new idea for underwater non - blasting excavation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is the longitudinal sectional view of the excavation, support and structure of the tunnel intake of the present invention.

[0042] Figure 2 It is the transverse sectional view of the excavation, support and structure of the tunnel intake of the present invention.

[0043] Figure 3 It is the three - dimensional structure schematic diagram of the tunnel intake structure under non - blasting construction under deep - water conditions of the present invention.

[0044] In Figure 1 , A1 represents the upstream of the tunnel; A2 represents the downstream of the tunnel; A3 represents the water level during the construction period; the arrow A4 represents the water flow direction;

[0045] In the figure, 1 - construction platform, 2 - construction shaft, 3 - curtain grouting, 4 - systematic anchor rod, 5 - primary reinforced concrete lining, 6 - underwater reserved rock sill, 7 - reinforced concrete structure, 7.1 - intake side wall, 7.11 - chute, 7.2 - intake bottom slab, 7.3 - concrete panel, 8 - tunnel inlet, 9 - multi - functional vortex - eliminating beam, 10 - trash rack. DETAILED DESCRIPTION OF THE INVENTION

[0046] The following will describe in detail the implementation of the present invention with reference to the attached drawings. However, they do not constitute a limitation to the present invention and are only for illustration purposes. At the same time, the advantages of the present invention will be made clearer and easier to understand through the description.

[0047] Referring to the attached drawings, it can be seen that: a tunnel intake structure under non - blasting construction under deep - water conditions is formed by excavation and pouring under deep - water conditions; the tunnel intake structure under non - blasting construction under deep - water conditions is in a trumpet shape;

[0048] The tunnel intake structure for non-explosive construction under deep water conditions includes a reinforced concrete structure 7 located underwater and a tunnel inlet 8;

[0049] The reinforced concrete structure 7 includes an intake side wall 7.1, an intake bottom plate 7.2, and a concrete panel 7.3;

[0050] The intake side walls 7.1 are respectively arranged on both sides of the construction shaft 2;

[0051] The intake bottom plate 7.2 is arranged at the bottom of the construction shaft 2 and at the bottom of the intake side walls 7.1;

[0052] The concrete panel 7.3 is arranged along the mountain slope at the downstream ends of the spaced intake side walls 7.1; One end of the concrete panel 7.3 is arranged above the tunnel inlet 8, and the other end extends upward beyond the intake side walls 7.1;

[0053] The tunnel inlet 8 is arranged at the lower part of the intake side walls 7.1 and at the outer lower end of the concrete panel 7.3;

[0054] The tunnel inlet 8 is connected to the trumpet-shaped structure formed by the reinforced concrete structure 7;

[0055] The multi-functional vortex-eliminating beam 9 is arranged between two spaced intake side walls 7.1 (as Figure 2 , Figure 3 shown).

[0056] Furthermore, there are multiple rows of the multi-functional vortex-eliminating beam 9, and the multiple rows of the multi-functional vortex-eliminating beam 9 are arranged at intervals longitudinally along the intake side walls 7.1;

[0057] Each row of the multi-functional vortex-eliminating beam 9 includes one or more multi-functional vortex-eliminating beams 9. The number of the multi-functional vortex-eliminating beams 9 in each row of the multi-functional vortex-eliminating beam 9 is the same or different (as Figure 3 shown), and the multi-functional vortex-eliminating beam 9 is used to support the reinforced concrete structure 7 and eliminate vortices at the same time.

[0058] Furthermore, the intake side walls 7.1 are in a right trapezoidal structure; The length of the upper end of the intake side walls 7.1 is greater than the length of the lower end; The concrete panel 7.3 is inclined.

[0059] Furthermore, the bottom plate of the tunnel inlet 8 is flush with the intake bottom plate 7.2 (as Figure 2 , Figure 3 shown).

[0060] Even further, a chute 7.11 is arranged at the downstream end of the intake side walls 7.1; The chute 7.11 is arranged along the downstream end of the intake side walls 7.1; The chute 7.11 is parallel to the concrete panel 7.3 and is located on the upstream side of the concrete panel 7.3;

[0061] The chute 7.11 is located at the connection between the side wall 7.1 of the water inlet and the concrete panel 7.3; the concrete panel 7.3 provides support and limit for the trash rack 10.

[0062] The length of the chute 7.11 is equal to the length of the downstream end of the side wall 7.1 of the water inlet.

[0063] The trash rack 10 is arranged on the chute 7.11 and is slidably connected to the chute 7.11 (as Figure 3 shown), and the trash rack 10 is used for intercepting and treating the upstream water flow of the tunnel water inlet structure under deep water conditions during non-explosive construction.

[0064] Referring to the attached drawings, it can be seen that the construction method of the tunnel water inlet structure under deep water conditions during non-explosive construction includes the following steps.

[0065] Step 1: Excavate the open cut on the downstream side of the underwater reserved rock sill 6 and the tunnel inlet slope to form a construction platform 1; determine the excavation range of the construction shaft on the construction platform 1 according to the dimensions of the tunnel water inlet structure; the rock sill 6 provides support and waterproof function for the construction shaft 2 to ensure construction safety during construction.

[0066] Step 2: Conduct single-row or double-row curtain grouting around the construction shaft determined in Step 1 to form a closed curtain grouting structure 3, and the curtain grouting structure 3 provides anti-seepage function for the construction shaft 2 to ensure construction safety during construction.

[0067] Step 3: Excavate and support the construction shaft 2 within the excavation range of the construction shaft determined in Step 1.

[0068] Before excavation, set a collar around the construction shaft; excavate the construction shaft 2 in the order from top to bottom.

[0069] During the construction of the construction shaft, use systematic rock bolts 4 and reinforced concrete primary lining 5 for support.

[0070] Step 4: Construct the tunnel water inlet structure.

[0071] Pour the reinforced concrete structure 7 in the construction shaft 2 in the order from bottom to top and support it through systematic rock bolts 4 and reinforced concrete primary lining 5.

[0072] Step 5: Excavate and support the lining of the tunnel inlet section.

[0073] Excavate the tunnel inlet section at the tunnel inlet 8 and support it through lining.

[0074] Step 6: After the construction of the tunnel inlet section is completed, close the tunnel gate and fill and level the tunnel inlet 8 with water.

[0075] Step 7: Cut the steel bars of the initial support on the upstream side of the construction shaft 2, and open an opening on the upstream side of the curtain grouting structure 3 so that the upstream water flow can pass through the curtain grouting structure 3 and enter the tunnel intake structure constructed without blasting under deep water conditions;

[0076] Select a long-arm excavator to demolish the underwater reserved rock sill 6 according to the construction water depth, so as to facilitate the upstream water flow to enter the tunnel intake structure constructed without blasting under deep water conditions (as shown in Figure 1 , Figure 2 , Figure 3 ).

[0077] Furthermore, in Step 1, the top elevation of the construction platform 1 should be above the construction period control water level and consider the safety super elevation according to the "Code for Design of Cofferdams in Water Resources and Hydropower Projects" (as shown in Figure 1 ), that is, the construction platform 1 is above the water level, and the size of the construction platform 1 needs to meet the requirements of the construction operation site.

[0078] In order to more clearly illustrate the advantages of the intake structure and its construction method without blasting under deep water conditions described in the present invention compared with the prior art, the staff compared these two technical solutions, and the comparison results are shown in Table 1 below:

[0079] Table 1 Comparison Results

[0080]

[0081] As can be seen from Table 1 above: Compared with the prior art, the intake structure and its construction method without blasting under deep water conditions described in the present invention have simple construction procedures, high safety performance, and low project investment.

[0082] Embodiment

[0083] Now, taking the application of the present invention to the tunnel intake construction of a certain reservoir in Hubei as an example, the present invention will be described in detail. It also has guiding significance for the construction of the tunnel intake structure without blasting under other deep water conditions of the present invention.

[0084] In this embodiment, a certain reservoir in Hubei has been in operation for more than 50 years. During the process of danger removal and reinforcement, the original culvert under the dam was blocked, and a new tunnel was built on the right bank mountain body of the dam. The slope of the mountain body on the upstream side of the tunnel inlet is relatively steep, with an average slope of about 40°. The bank slope bedrock is exposed, consisting of argillaceous siltstone and sandy claystone. The rock strata dip south-southwest with an inclination angle of about 17°. The bank slope is an inclined to transverse slope. The water level during the construction period of the reservoir is 12 m higher than the bottom elevation of the tunnel intake. At the same time, due to topographical conditions, it is impossible to build a temporary water retaining cofferdam, and it is impossible to use the conventional rock plug blasting method for construction. Or even if the rock plug blasting method is used for construction, it will greatly increase the project investment cost.

[0085] Now, the underwater non-explosion construction structure and method of the present invention are adopted to construct the tunnel inlet structure under deep water conditions in this embodiment.

[0086] As Figure 1 , Figure 2 shown, in this embodiment, the construction method of the tunnel inlet structure for non-explosion construction under deep water conditions of the present invention is adopted to construct the tunnel inlet structure of a reservoir in Hubei, including the following steps:

[0087] Step (1): Excavate the construction platform 1 according to the slope ratio of the slope excavation. The length and width of the construction platform 1 need to be determined in combination with the dimensions of the inlet structure and the construction shaft, and at the same time, the thickness of the reserved rock sill 6 should be satisfied; the elevation of the construction platform 1 is determined according to the top elevation of the reserved rock sill 6, and the safety super elevation needs to be considered in accordance with the "Design Code for Cofferdams in Water Conservancy and Hydropower Projects".

[0088] Step (2): Determine the scope of the construction shaft 2 at the construction platform 1 formed in step (1). The size of the construction shaft 2 is determined according to the dimensions of the inlet structure; curtain grouting is carried out 3 - 5 m outside the side line range of the construction shaft 2 to form a closed curtain grouting structure 3. The number of grouting rows is determined according to the permeability of the rock formation, and the grouting depth penetrates into the relatively impermeable layer and shall not be higher than the bottom elevation of the inlet structure.

[0089] Step (3): Excavate the construction shaft 2. Before excavation, lock the mouth around the construction shaft 2. The excavation is carried out by using a milling excavator in cooperation with an excavator, and the method of excavating while supporting is adopted during the excavation process. System bolts 4 and reinforced concrete primary lining 5 are used for support.

[0090] Step (4): Pour the reinforced concrete structure 7 of the tunnel inlet in the construction shaft 2 formed in step (3). The multi-functional vortex-eliminating beam 9 structure can support and connect the reinforced concrete structure 7, and at the same time play a role in eliminating vortices.

[0091] Step (5): Carry out the excavation of the tunnel inlet 8 and the tunnel.

[0092] Step (6): After the tunnel construction is completed, close the tunnel gate and carry out water filling and pressure equalization for the tunnel inlet 8.

[0093] Step (7): Install the trash rack 10.

[0094] Step (8): Cut off the steel bars of the initial support on the side of the shaft facing the water surface, and select a long-arm excavator to carry out underwater removal of the rock sill according to the construction water depth (where the underwater removal method of the rock sill is an existing technology).

[0095] Conclusion: In this embodiment, the method of the present invention is adopted to construct the tunnel inlet structure of a reservoir in Hubei. The construction procedure is simple and efficient, without the need for special blasting design and special approval, and there is no need to monitor the blasting vibration velocity during the construction process, saving time cost and investment cost; in this embodiment, mechanical excavation construction is adopted by the inventive method, with higher safety; the project investment of this embodiment using the method of the present invention is about 3.69 million yuan, and the project investment of the same construction using the existing blasting construction method is about 4.98 million yuan. Compared with the blasting construction method, the technical solution of this embodiment through the inventive construction method is innovative and saves about 35% of the project investment, achieving commercial success.

[0096] Other parts not described belong to the prior art.

Claims

1. A construction method for the inlet structure of a tunnel under non-explosive construction in deep water conditions, characterized in that: It is excavated and cast under deep - water conditions; the intake structure of the tunnel under non - blasting construction in deep - water conditions is trumpet - shaped; The intake structure of the tunnel under non - blasting construction in deep - water conditions includes a reinforced concrete structure (7) located underwater and a tunnel inlet (8); The reinforced concrete structure (7) includes intake side walls (7.1), an intake bottom slab (7.2), and a concrete panel (7.3); The intake side walls (7.1) are respectively arranged on both sides of the construction shaft (2); the intake bottom slab (7.2) is arranged at the bottom of the construction shaft (2) and is located at the bottom of the intake side walls (7.1); The concrete panel (7.3) is arranged along the mountain slope at the downstream ends of the spaced intake side walls (7.1); one end of the concrete panel (7.3) is arranged above the tunnel inlet (8), and the other end extends upward beyond the intake side walls (7.1); The tunnel inlet (8) is arranged at the lower part of the intake side walls (7.1) and is located at the outer lower end of the concrete panel (7.3); The tunnel inlet (8) is connected to the trumpet - shaped structure formed by the reinforced concrete structure (7); The multi - functional vortex - eliminating beam (9) is arranged between the two spaced intake side walls (7.1); A chute (7.11) is arranged at the downstream end of the intake side walls (7.1); the chute (7.11) is located at the connection between the intake side walls (7.1) and the concrete panel (7.3); The length of the chute (7.11) is equal to the length of the downstream end of the intake side walls (7.1); The trash rack (10) is arranged on the chute (7.11) and is slidably connected to the chute (7.11); The described construction method includes the following steps, Step 1: Excavate the surface of the tunnel inlet slope on the downstream side of the underwater reserved rock sill (6) to form a construction platform (1); determine the excavation range of the construction shaft on the construction platform (1) according to the dimensions of the intake structure of the tunnel; Step 2: Conduct single - row or double - row curtain grouting around the construction shaft determined in Step 1 to form a closed curtain grouting structure (3); Step 3: Excavate and support the construction shaft (2) within the excavation range of the construction shaft determined in Step 1; Before excavation, set a collar around the construction shaft; excavate the construction shaft (2) in the order from top to bottom; During the construction of the construction shaft, use systematic rock bolts (4) and a reinforced concrete primary lining (5) for support; Step 4: Construct the intake structure of the tunnel; Pour the reinforced concrete structure (7) in the construction shaft (2) in the order from bottom to top and support it with systematic rock bolts (4) and a reinforced concrete primary lining (5); Step 5: Excavate and line and support the tunnel inlet section; Excavate the tunnel inlet section at the tunnel inlet (8) and line and support it; Step 6: After the construction of the tunnel inlet section is completed, close the tunnel gate and conduct water filling and pressure equalization for the tunnel inlet (8); Step 7: Cut off the steel bars of the initial support on the water - facing side of the construction shaft (2) and open an opening on the upstream side of the curtain grouting structure (3) so that the upstream water can pass through the curtain grouting structure (3) and enter the intake structure of the tunnel under non - blasting construction in deep - water conditions; Select a long - arm excavator to demolish the underwater reserved rock sill (6) according to the construction water depth.

2. The construction method of the tunnel water inlet structure for non-blasting construction under deep water conditions according to claim 1, characterized in that: The multi-functional vortex-eliminating beams (9) have multiple rows, and the multiple rows of multi-functional vortex-eliminating beams (9) are arranged at intervals along the longitudinal direction of the water inlet side wall (7.1); Each row of multi-functional vortex-eliminating beams (9) includes one or more multi-functional vortex-eliminating beams (9).

3. The construction method of the tunnel water inlet structure for non-blasting construction under deep water conditions according to claim 1 or 2, characterized in that: The water inlet side wall (7.1) has a right trapezoidal structure; the length of the upper end of the water inlet side wall (7.1) is greater than the length of the lower end.

4. The construction method of the tunnel water inlet structure for non-blasting construction under deep water conditions according to claim 3, characterized in that: The bottom plate of the tunnel inlet (8) is flush with the water inlet bottom plate (7.2).

5. The construction method of the tunnel inlet structure for non-explosive construction under deep water conditions according to claim 1, characterized in that: In the first step, the construction platform (1) is above the water level, and the size of the construction platform (1) meets the needs of the construction operation site.

Images