A double steel lining - reinforced concrete precast composite structure pressure pipe and its construction method

Abstract

The present invention discloses a double steel lining-reinforced concrete prefabricated composite structure pressure pipe and a construction method thereof, comprising backfill concrete and a prefabricated composite structure, wherein the prefabricated composite structure comprises a steel outer lining, lining concrete, a steel inner lining and a steel bar fixing piece; the backfill concrete is located between a boundary line of a surrounding rock excavation and the prefabricated composite structure, and the prefabricated composite structure comprises a steel inner lining, lining concrete and a steel outer lining from the inside to the outside; circumferential stress-bearing steel bars are arranged in the lining concrete, and the circumferential stress-bearing steel bars are connected to the steel bar fixing piece; the circumferential joints of the steel outer lining are connected by flanges and high-strength bolts; the circumferential joints of the steel inner lining are welded with an inner single-sided groove; a water stop is arranged at the flange joint, and the double steel lining-reinforced concrete prefabricated composite structure solves the stability problem of the steel lining under external water pressure, adopts a double steel lining structure, reduces the thickness of a single-layer steel lining and reduces the weight, can increase the length of a single-section steel lining, and reduces the number of circumferential joints, thereby saving engineering workload and construction period.

Description

Technical Field

[0001] The invention belongs to the field of pressure pipe structures and relates to a double steel lining-reinforced concrete prefabricated composite structure pressure pipe and a construction method thereof. Background Art

[0002] Currently, pumped-storage power stations require significant investment, costing approximately 6,000 yuan per kilowatt-hour, with hub projects accounting for approximately 60% of this cost. High-pressure steel pipes are a common structure in the water supply systems of high-head power stations. Their structure primarily consists of a single steel lining with concrete backfill. To ensure the lining's stability under external water pressure, circumferential stiffening ribs are added to the outside of the lining, representing approximately 15% of the total high-pressure steel pipe volume. The single-line structure requires a thicker steel lining, and double-bevel welds are often used for circumferential joints. However, due to the limited on-site construction space, the outer welds are not only slow to install but also difficult to ensure quality. The unit cost of the penstock lining is as high as 15,000 to 30,000 yuan per ton, two to four times the unit cost of steel reinforcement. Therefore, improvements to the structure of high-pressure water supply steel pipes are necessary for both time and cost considerations. Summary of the Invention

[0003] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a double steel lining-reinforced concrete prefabricated composite structure pressure pipe. This structural form saves the outer annular stiffening ribs and reduces the thickness of the outer backfill concrete. The annular seam of the steel outer lining is connected by flange bolts, and the steel inner lining is connected by an inner single-sided groove welding. The use of a prefabricated structure saves construction period; the contribution of steel bars is taken into account, the total thickness of the steel lining is reduced, etc. The design concept is clear and easy to implement.

[0004] To achieve the above-mentioned object, the present invention adopts a solution as follows: a double steel lining-reinforced concrete prefabricated composite structure pressure pipe, comprising a surrounding rock excavation boundary line, backfill concrete and a prefabricated composite structure, wherein the prefabricated composite structure comprises a steel outer lining, a flange connecting the annular seam of the steel outer lining, high-strength bolts, lining concrete, annular stress-bearing steel bars, a steel inner lining and steel bar fixings;

[0005] The backfill concrete is located between the boundary line of the surrounding rock excavation and the prefabricated composite structure. The prefabricated composite structure is composed of a steel lining, lining concrete, and a steel outer lining from the inside to the outside. Circumferential stress-bearing steel bars are set in the lining concrete and connected to steel bar fixings. The steel bar fixings are welded to the steel lining or steel outer lining.

[0006] The circumferential joints of the steel outer lining are connected by flanges and high-strength bolts; the circumferential joints of the steel inner lining are connected by inner single-sided groove welding; waterstops are set at the flange joints of the two adjacent sections of prefabricated composite structures.

[0007] Backfill concrete and lining concrete are made of micro-expansive concrete, fiber concrete or micro-expansive fiber concrete.

[0008] The waterstop extends radially to the lining concrete.

[0009] The steel bar fixings are studs or lugs, which also serve as anchors for the steel outer lining or steel inner lining and the lining concrete.

[0010] The circumferential stress-bearing steel bars and steel bar fixings are connected by binding.

[0011] The circumferential stress reinforcement adopts single layer or double layer reinforcement.

[0012] Adjacent prefabricated composite structures are connected using F-type tongue and groove connections.

[0013] The waterstop between adjacent prefabricated composite structures adopts water-expanding waterstop.

[0014] The construction method of the double steel lining-reinforced concrete prefabricated composite pressure pipe of the present invention comprises the following steps:

[0015] 1) After the excavation of the water pipe cavern is completed, a grouting pipe is reserved on the rock wall;

[0016] 2) Construction of consolidation slurry pipe;

[0017] 3) Install the prefabricated composite structure and construct the annular joints of the steel outer lining and the steel inner lining of the prefabricated composite structure;

[0018] 4) Construction backfill concrete;

[0019] 5) Construction backfill grouting and contact grouting;

[0020] Construction step 4) is carried out alternately with construction step 3).

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The double steel lining-reinforced concrete precast composite structure solves the problem of steel lining stability under external water pressure, eliminating the original structure's circumferential stiffeners. The steel outer lining uses flanges and high-strength bolts for circumferential joints, while the steel inner lining uses single-sided groove welding on the inside for circumferential joints. This solves the problem of construction difficulties caused by the narrow welding space on the outside. The double steel lining structure reduces the thickness and weight of the single-layer steel lining, increases the length of a single steel lining section, and reduces the number of circumferential joints. The installation of circumferential stress-bearing steel bars can effectively reduce the total thickness of the steel lining and lower the unit cost of the pressure pipe. The steel bar fixings can also serve as anchoring components, effectively bonding the steel outer lining / steel inner lining to the lining concrete, ensuring the smooth transmission of radial axial force. The precast composite structure uses prefabricated components, which shortens the construction period. This structure not only saves engineering work and construction time, but is also easy to implement on site, saving overall project costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is a cross-sectional schematic diagram of the present invention;

[0024] Figure 2 This is a schematic cross-sectional view of the prefabricated composite structure 3 of the present invention;

[0025] Figure 3 This is a three-dimensional front view of the prefabricated composite structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the tongue-and-groove connection of three prefabricated composite structures of the present invention;

[0027] Figure 5 Schematic diagram of the circumferential single-sided groove welding of the steel liner of the present invention;

[0028] In the attached figure: 1- boundary line of surrounding rock excavation; 2- backfill concrete; 3- prefabricated composite structure; 31- steel outer lining; 32- lining concrete; 33- circumferential stress-bearing steel bars; 34- steel inner lining; 35- flange; 36- high-strength bolts; 37- steel bar fixings; 38- circumferential joint; 39- waterstop. DETAILED DESCRIPTION

[0029] The present invention will be described in further detail below with reference to the accompanying drawings.

[0030] See also Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 The double steel lining-reinforced concrete prefabricated composite structure pressure pipe of the present invention includes a surrounding rock excavation boundary line 1, backfill concrete 2 and a prefabricated composite structure 3. The prefabricated composite structure 3 includes a steel outer lining 31, a flange 35 connecting the circumferential seam of the steel outer lining 31, high-strength bolts 36, lining concrete 32, circumferential stress-bearing steel bars 33, a steel inner lining 34 and steel bar fixing parts 37.

[0031] The backfill concrete 2 is located between the boundary line 1 of the surrounding rock excavation and the prefabricated composite structure 3. The prefabricated composite structure 3 is composed of a steel lining 34, a lining concrete 32 and a steel outer lining 31 from the inside to the outside. Circumferential stress-bearing steel bars 33 are arranged in the lining concrete 32, and the circumferential stress-bearing steel bars 33 are connected to steel bar fixings 37. The steel bar fixings 37 are welded to the steel lining 34 or the steel outer lining 31. The circumferential joint of the steel outer lining 31 is connected by a flange 35 and a high-strength bolt 36. The circumferential joint 38 of the steel lining 34 is connected by an inner single-sided groove weld, such as Figure 5 The flange joints of the two adjacent prefabricated composite structures 3 are provided with a waterstop 39, as shown Figure 4 As shown,.

[0032] The backfill concrete 2 and the lining concrete 32 are made of micro-expansive concrete, fiber concrete or micro-expansive fiber concrete.

[0033] The steel bar fixing member 37 adopts a stud or an ear plate, which also serves as an anchor for the steel outer lining 31 / steel inner lining 34 and the lining concrete 32. The circumferential stress reinforcement 32 and the steel bar fixing member 37 are connected by binding. The circumferential stress reinforcement 32 adopts a single layer of reinforcement or a double layer of reinforcement.

[0034] Adjacent prefabricated composite structures 3 are connected by F-type tongue-and-groove connections, and the waterstops between adjacent prefabricated composite structures 3 are water-expandable waterstops.

[0035] The steel outer lining 31 and the steel inner lining 34 are made of ordinary steel or high-strength steel, and the stress-bearing steel bars 32 are made of HRB400 steel.

[0036] The double steel lining-reinforced concrete prefabricated composite structure pressure pipe of the present invention comprises the following steps:

[0037] 1) After the excavation of the water pipe cavern is completed, a grouting pipe is reserved on the rock wall;

[0038] 2) Construction of consolidation slurry pipe;

[0039] 3) Installing the prefabricated composite structure 3, and constructing the circumferential seams of the steel outer lining 31 and the steel inner lining 34 of the prefabricated composite structure 3;

[0040] 4) Construction backfill concrete 2;

[0041] 5) Construction backfill grouting and contact grouting;

[0042] 6) Construction step 4) and construction step 3) can be carried out alternately.

[0043] The present invention is characterized in the following aspects:

[0044] The double steel lining-reinforced concrete precast composite structure solves the problem of steel lining stability under external water pressure, eliminating the need for circumferential stiffeners in a single steel lining structure. The circumferential joints of the steel outer lining 31 are connected using flanges and high-strength bolts, with waterstops installed at the flange joints. The circumferential joints of the steel inner lining 34 are welded using a single-sided groove weld on the inside, resolving the construction difficulties caused by the limited space for welding on the outside. The double steel lining structure reduces the thickness and weight of the steel outer lining 31 or steel inner lining 34 compared to a single steel lining structure, allowing the length of a single steel lining section to be increased, thereby reducing the number of circumferential joints. The circumferential force-bearing reinforcement 33 effectively reduces the combined thickness of the steel outer lining 31 and steel inner lining 34. The reinforcement fasteners 37 effectively bond the steel outer lining 31 and steel inner lining 34 to the lining concrete 32, ensuring smooth transmission of radial axial forces. The precast composite structure 3 uses prefabricated components, shortening the construction period. This invention not only saves engineering effort and construction time, but also facilitates on-site implementation.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. A person skilled in the art may modify or substitute equivalents for the specific implementation schemes of the present invention. Any modifications or equivalent substitutions that do not deviate from the spirit and principles of the present invention are intended to be within the scope of protection of the claims of the present invention.

Claims

1. A double steel lining-reinforced concrete prefabricated composite structure pressure pipe, characterized in that: The invention comprises a surrounding rock excavation boundary line (1), backfill concrete (2) and a prefabricated composite structure (3), wherein the prefabricated composite structure (3) comprises a steel outer lining (31), a flange (35) connecting the circumferential seam of the steel outer lining (31), high-strength bolts (36), lining concrete (32), circumferential stress-bearing steel bars (33), a steel inner lining (34) and steel bar fixing parts (37); The backfill concrete (2) is located between the boundary line of the surrounding rock excavation (1) and the prefabricated composite structure (3), and the prefabricated composite structure (3) is composed of a steel lining (34), lining concrete (32), and a steel outer lining (31) from the inner side to the outer side; a circumferential stress-bearing steel bar (33) is arranged in the lining concrete (32), and the circumferential stress-bearing steel bar (33) is connected to a steel bar fixing member (37); and the steel bar fixing member (37) is welded to the steel lining (34) or the steel outer lining (31); The circumferential joint of the steel outer lining (31) is connected by a flange (35) and a high-strength bolt (36); the circumferential joint (38) of the steel inner lining (34) is connected by an inner single-sided groove welding; a water stop (39) is provided at the flange joint of two adjacent sections of the prefabricated composite structure (3); the water stop (39) radially extends to the lining concrete (32); the steel bar fixing member (37) adopts a bolt or an ear plate, and serves as an anchor member for the steel outer lining (31) or the steel inner lining (34) and the lining concrete (32); and the adjacent prefabricated composite structures (3) are connected by an F-type tongue and groove.

2. The double steel lining-reinforced concrete prefabricated composite structure pressure pipe according to claim 1 is characterized in that: The backfill concrete (2) and the lining concrete (32) are made of micro-expansion concrete, fiber concrete or micro-expansion fiber concrete.

3. The double steel lining-reinforced concrete prefabricated composite structure pressure pipe according to claim 1 is characterized in that: The annular stressed steel bars (32) and the steel bar fixing members (37) are connected by binding.

4. The double steel lining-reinforced concrete prefabricated composite structure pressure pipe according to claim 1, characterized in that: The hoop-type stress-bearing reinforcement (32) adopts single-layer reinforcement or double-layer reinforcement.

5. The double steel lining-reinforced concrete prefabricated composite structure pressure pipe according to claim 1, characterized in that: The waterstop between adjacent prefabricated composite structures (3) adopts a water-expanding waterstop.

6. The construction method of the double steel lining-reinforced concrete prefabricated composite pressure pipe according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) After the excavation of the water pipe cavern is completed, a grouting pipe is reserved on the rock wall; 2) Construction of consolidation slurry pipe; 3) installing the prefabricated composite structure (3), and constructing the circumferential seams of the steel outer lining (31) and the circumferential seams of the steel inner lining (34) of the prefabricated composite structure (3); 4) Construction backfill concrete (2); 5) Construction of backfill grouting and contact grouting.

7. The construction method according to claim 6, characterized in that: Construction step 4) is carried out alternately with construction step 3).

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