Casting method for reinforcing quality of top of diaphragm wall

Abstract

The invention relates to the technical field of civil construction engineering construction, in particular to an anti-seepage wall top quality strengthening pouring method which comprises the following steps: S1, conventional stage pouring; s2, system switching is conducted, specifically, when the liquid level of concrete in the slotted hole of the diaphragm wall rises to the preset height away from the elevation of the top face of the guide wall, pouring of the conventional guide pipe vertical lifting method is stopped, and the part, above the top face of the guide wall, of the conventional pouring guide pipe is dismantled; s3, an extended pouring guide pipe is installed, specifically, the extended pouring guide pipe is installed at the original guide pipe position; s4, a sky pump is poured; s5, high-pressure head pouring is maintained; and S6, finishing and dismounting. In the wall top pouring stage, the extended pouring guide pipe is actively lifted and the liquid level height of the concrete in the extended pouring guide pipe is maintained, so that a large enough and stable natural pressure difference is rebuilt and maintained, it is ensured that top smooth pouring of the concrete is completed under the constant and sufficient self-weight pressure, pipe lifting disturbance can be fundamentally avoided, and the construction efficiency is improved. And a dense, uniform and high-quality top section wall body is obtained.

Description

Technical Field

[0001] This invention relates to the field of civil engineering construction technology, and in particular to a method for reinforcing the quality of the top of a seepage-proof wall by pouring concrete. Background Technology

[0002] As a key seepage prevention structure in large-scale water conservancy and hydropower projects, the continuity and uniformity of ultra-deep concrete cutoff walls are of paramount importance. Currently, the "direct-lift method" is commonly used for concrete pouring: a duct with an open bottom is inserted into the bottom of the trench, and concrete is injected through the duct. The difference in the liquid level between the inside and outside of the duct (i.e., the static pressure generated by the weight of the concrete) displaces the mud in the trench, thus forming a continuous wall.

[0003] However, in the construction of walls hundreds of meters deep, the existing conventional tremie pipe method has the following drawbacks when pouring concrete to the top of the wall: when the concrete level approaches the designed top elevation, the difference in liquid level (Δh) between the inside and outside of the tremie pipe decreases sharply, leading to a decrease in the natural pressure (P=ρ) required to propel the concrete flow and compaction. g The concrete level (Δh) is severely insufficient. In order to barely complete the final stage of pouring, construction workers are often forced to adopt the emergency measure of "repeatedly lifting the guide pipe up and down". This operation will seriously disrupt the smooth replacement process of concrete in the trench, and it is very easy for the poured concrete to mix with the wall slurry, forming a weak layer of "mud inclusion" or "loose" with low strength and poor impermeability in the top area of ​​the wall. This is the root cause of the substandard quality of the top of the anti-seepage wall, which often requires a large amount of over-pouring and subsequent manual removal. This not only causes material waste and increased costs, but also affects construction efficiency and overall structural reliability.

[0004] Therefore, there is an urgent need for a method to enhance the quality of the top of the seepage barrier wall by maintaining a sufficient and stable natural pressure head during the top pouring stage, thereby avoiding disturbance during pipe lifting and effectively ensuring the original quality of the top concrete. Summary of the Invention

[0005] The purpose of this invention is to provide a method for reinforcing the top of a seepage-proof wall by pouring concrete, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: a method for reinforcing the top of a seepage-proof wall by casting concrete, comprising the following steps: S1. Conventional stage pouring: The initial and intermediate pouring of concrete in the trench of the anti-seepage wall is carried out using the conventional tremie pipe method. S2. System Switching: When the concrete level in the anti-seepage wall trench rises to the predetermined elevation above the top of the guide wall, stop the conventional duct straight-up method of pouring and remove the conventional pouring duct above the top of the guide wall. S3. Install an extended pouring pipe: Install an extended pouring pipe at the original pipe location; S4. Top pump pouring: Place the outlet of the top pump's delivery pipe inside the port at the top of the extended pouring conduit; S5. Maintain high pressure head during pouring: Under the continuous supply of the super pump, the concrete liquid level in the extended pouring pipe is higher than the concrete liquid level in the anti-seepage wall trench. The concrete in the extended pouring pipe completes the pouring of the top section of the wall through the static pressure generated by the liquid level height difference Δh. S6. End and Dismantling: After pouring is completed, wait for the concrete level in the extended pouring pipe to drop appropriately before dismantling the extended pouring pipe.

[0007] Preferably, the predetermined elevation in step S2 is the switching elevation, which is 2.0 meters to 6.0 meters.

[0008] Preferably, in step S3, the extended casting conduit is constructed using one or more sections.

[0009] Preferably, the extended pouring pipe is connected to the original pipe embedded in the concrete and the two adjacent extended pouring pipes using a special connector.

[0010] Preferably, the top of the extended pouring pipe at the top is higher than the construction ground by a certain height, which is H_extension. Through H_extension, the concrete liquid in the extended pouring pipe forms the minimum effective head that meets the quality requirements: Δh_min.

[0011] Preferably, a concrete level detector is installed inside the top of the uppermost extended pouring pipe.

[0012] Preferably, the delivery pump pipe extends 0.5 meters into the top of the uppermost extended pouring conduit.

[0013] Preferably, the distance between the installation position of the concrete liquid level detector and the top of the uppermost extended pouring pipe is less than 0.5 meters.

[0014] Preferably, the concrete level inside the extended pouring duct is monitored in real time using a concrete level detector.

[0015] Preferably, the liquid level difference Δh is greater than or equal to the minimum effective head Δh_min.

[0016] The present invention discloses the following technical effects: In the top-pouring stage of the wall, this invention actively raises and maintains the liquid level of the concrete in the extended pouring pipe by extending the pouring pipe, thereby reconstructing and maintaining a sufficiently large and stable natural pressure difference. This ensures that the concrete is successfully poured at the top under constant and sufficient self-weight pressure, fundamentally avoiding pipe lifting disturbance and obtaining a dense, uniform, and high-quality top-section wall. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure during the casting process of the present invention; Among them, 1. Conveying pump; 2. Delivery pump pipe; 3. Extended pouring guide pipe; 4. Triangular bracket; 5. Top surface of guide wall; 6. Concrete liquid level detector. Detailed Implementation

[0019] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 Reference Figure 1 This invention provides a method for reinforcing the top of a seepage-proof wall by casting concrete, comprising the following steps: S1. Conventional stage pouring: The initial and intermediate pouring of concrete in the trench of the anti-seepage wall is carried out using the conventional tremie pipe method.

[0022] S2. System Switching: When the concrete level in the anti-seepage wall trench rises to the predetermined elevation of 5 meters above the top surface of the guide wall, the conventional duct straight-up method of pouring is stopped, and the conventional pouring duct above the top surface of the guide wall is removed; the predetermined elevation is the switching height, which is 2.0 meters to 6.0 meters.

[0023] S3. Install extension pouring pipe 3: Install extension pouring pipe 3 at the original pipe position; extension pouring pipe 3 may be one or more sections; extension pouring pipe 3 is connected to the original pipe embedded in the concrete and to two adjacent extension pouring pipes 3 using a special connector.

[0024] The extended pouring pipe 3 is supported by a triangular bracket 4, which enables the extended pouring pipe 3 to be installed vertically.

[0025] The top of the extended pouring pipe 3 at the top is a certain height above the construction ground, which is H_extension. Through H_extension, the concrete liquid in the extended pouring pipe 3 forms the minimum effective head that meets the quality requirements: Δh_min.

[0026] A concrete level detector 6 is installed inside the top of the uppermost extended pouring pipe 3. The distance between the installation position of the concrete level detector 6 and the top of the uppermost extended pouring pipe 3 is less than 0.5 meters. The concrete level detector 6 monitors the pouring level of the concrete in the extended pouring pipe 3 in real time.

[0027] S4. Casting with the top pump 1: Place the outlet of the delivery pump pipe 2 of the top pump 1 into the port at the top of the extended casting conduit 3; the delivery pump pipe 2 extends 0.5 meters into the top of the uppermost extended casting conduit 3.

[0028] The Tianpeng 1 can also be replaced by a truck pump or a boom pump.

[0029] Concrete is poured directly into the extended pouring pipe 3 via the overhead pump 1. By controlling the pumping speed of the overhead pump 1, the concrete is injected continuously and smoothly.

[0030] S5. Maintaining high pressure head during pouring: Under the continuous supply of material from the super pump 1, the concrete liquid level in the extended pouring pipe 3 is higher than the concrete liquid level in the anti-seepage wall trench. The concrete in the extended pouring pipe 3 completes the pouring of the top section of the wall through the static pressure generated by the liquid level height difference Δh.

[0031] By creating a stable and sufficiently large liquid level difference Δh between the high-level liquid level and the liquid level in the tank, and with the liquid level difference Δh ≥ minimum effective head Δh_min, the concrete can smoothly and steadily fill the slot space at the top of the wall and completely replace the mud without any guide pipe lifting operation, until the concrete liquid level reaches the designed top wall elevation.

[0032] S6. End and dismantling: After the pouring is completed, wait for the concrete level in the extended pouring pipe 3 to drop appropriately before dismantling the extended pouring pipe 3.

[0033] In the top pouring stage of the wall, this invention actively raises and maintains the liquid level of the concrete inside the extended pouring pipe 3 by extending the pouring pipe 3, thereby reconstructing and maintaining a sufficiently large and stable natural pressure difference. This ensures that the concrete is successfully poured at the top under constant and sufficient self-weight pressure, fundamentally avoiding pipe lifting disturbance and obtaining a dense, uniform, and high-quality top wall section.

[0034] In this invention, when the conventional duct straight-up method reaches the top area of ​​the wall, the original duct is replaced with a vertically extended pouring duct 3 with its top above the ground. Concrete is poured directly and continuously from the top port of the extended pouring duct 3, thereby actively establishing and maintaining a concrete column in the extended pouring duct 3 that is much higher than the liquid level in the groove. The strong and stable static pressure generated by the significantly increased liquid level height difference Δh is used to complete the pouring of the top section of the wall.

[0035] Example 2 Based on Example 1, the construction of the anti-seepage wall of a reservoir dam was carried out.

[0036] 1. Project Overview: A certain reservoir dam requires the construction of a 100-meter-deep plastic concrete cutoff wall, with a designed top elevation of ±0.00m (flush with the top surface of the guide wall). The design strength of the concrete is C15.

[0037] 2. Determination of design parameters: Minimum effective head (Δh_min): Based on concrete properties and experience from similar projects, the minimum liquid level difference Δh_min that needs to be maintained to ensure top compaction is determined to be 3.0 meters.

[0038] Switching height: 2.0 meters is the set height. That is, the system will switch when the concrete level in the tank rises to 2.0 meters from the design top wall (±0.00m).

[0039] Height of extended pouring pipe 3 (H_extended): To ensure sufficient rise space for the liquid level in the extended pouring pipe 3 during the entire top pouring process to maintain Δh_min, and considering operational safety margin, the design H_extended is 6.0 meters (i.e., the top of the uppermost extended pouring pipe 3 is 6 meters above the ground).

[0040] 3. Construction steps: Step 1 (Conventional Pouring): Concrete is poured using the conventional tremie pipe method, with close monitoring of the liquid level in the tank.

[0041] Step Two (Switching and Installation): When the monitoring shows that the liquid level in the tank has risen to -2.0m (i.e., 2 meters from the top of the wall), stop the regular pouring. Quickly remove the guide pipe above the top surface 5 of the guide wall, and install and connect the 6-meter-high vertical extension pouring guide pipe 3 with the concrete liquid level detector 6 at the top. Ensure that the lower part of the extension pouring guide pipe 3 at the bottom is reliably connected and sealed to the original guide pipe.

[0042] Step 3 (Top Pump 1): Call in a 52-meter boom concrete top pump, align the outlet of the delivery pump pipe 2 with the outlet and insert it into the top port of the extended pouring pipe 3 about 0.5 meters.

[0043] Step 4 (High-pressure head pouring): ① Start the overhead pump 1 and pour concrete into the extended pouring pipe 3 at a stable speed.

[0044] ② The concrete quickly fills the extended pouring pipe 3, and the liquid level inside the extended pouring pipe 3 rises rapidly; the operational objective is to maintain the liquid level inside the extended pouring pipe 3 at a position at least 3.0 meters higher than the liquid level in the current tank.

[0045] For example, if the initial liquid level in the tank is -2.0m, the liquid level inside the extended pouring guide pipe 3 should reach approximately +1.0m (1 meter above ground) or higher. This height can be detected by the concrete liquid level detector 6, and the pumping pressure and feed rate of the overhead pump 1 can be adjusted based on the detected concrete liquid level height.

[0046] ③ Under this stable high pressure difference (Δh ≥ 3.0m), the concrete settles smoothly, replacing the mud in the trench, causing the liquid level in the trench to rise continuously and slowly.

[0047] Key operational points: Throughout the entire process, it is strictly forbidden to lift or disassemble the extended pouring guide pipe 3. The on-site supervisor uses data from the concrete level gauge 6 to determine the height of the concrete pouring level inside the guide pipe. The operator of the overhead pump 1 only needs to maintain continuous and uniform material supply according to the on-site supervisor's instructions, ensuring Δh ≥ Δh_min.

[0048] Compared with the conventional catheter-directed method, the present invention has the following significant technical advantages: 1. Completely eliminates potential quality problems: By establishing and maintaining a constant and sufficient natural pressure head (Δh), the "lifting" operation that is forced to be carried out at the end of the traditional method is completely avoided, thereby fundamentally eliminating common quality problems such as "mud inclusion" and "looseness" of the concrete at the top of the wall caused by the disturbance of lifting the pipe.

[0049] 2. Significantly improves the quality of the top section: The continuous and strong static pressure fully compresses the concrete at the top of the wall, effectively expelling internal water and air bubbles, and making the aggregate distribution more uniform. This significantly improves the density, strength, and impermeability of the concrete in this section, ensuring the overall continuity of the wall quality.

[0050] 3. Simple and reliable construction operation: The principle of the method for reinforcing the top of the seepage barrier wall according to the present invention is clear. It only requires the addition of two steps to the existing process: "replacing the extended pouring pipe 3" and "using the top pump 1 for top grouting". The top pump 1 is a general equipment for commercial concrete pouring. It is easy to operate, the material supply is continuous and controllable, the construction process is smooth, there are no special requirements for workers' skills, and it is easy to promote and apply in various construction sites.

[0051] 4. Significant economic benefits: Because the original quality of the concrete at the top of the wall is guaranteed, the amount of "over-pouring" concrete required to obtain a qualified wall can be greatly reduced (usually by more than 50%), saving material costs; at the same time, it reduces the mechanical and labor costs of removing inferior concrete later, shortens the construction period, and the overall economic benefits are obvious.

[0052] 5. Controllable parameters and stable quality: By scientifically designing and extending the height of the pouring guide pipe 3 (H_extension) and switching the height, the effective pressure head Δh can be quantitatively controlled, so that the construction quality changes from "relying on experience" to "being guaranteed by parameters", and the quality reproducibility is good.

[0053] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0054] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for reinforcing the top of a seepage-proof wall by casting concrete, characterized in that: Includes the following steps: S1. Conventional stage pouring: The initial and intermediate pouring of concrete in the trench of the anti-seepage wall is carried out using the conventional tremie pipe method. S2. System switching: When the concrete liquid level in the anti-seepage wall trench rises to the predetermined height from the top surface (5) of the guide wall, stop the pouring of the conventional duct straight-up method and remove the conventional pouring duct above the top surface (5) of the guide wall. S3. Install extended pouring pipe (3): Install extended pouring pipe (3) at the original pipe position; S4. Casting with the super pump (1): Place the outlet of the super pump (1) delivery pipe (2) inside the port at the top of the extended casting conduit (3); S5. Maintain high pressure head during pouring: Under the continuous supply of the super pump (1), the concrete liquid level in the extended pouring pipe (3) is higher than the concrete liquid level in the anti-seepage wall groove. The concrete in the extended pouring pipe (3) completes the pouring of the top section of the wall through the static pressure generated by the liquid level height difference Δh. S6. End and dismantling: After the pouring is completed, wait for the concrete level in the extended pouring pipe (3) to drop appropriately, then dismantle the extended pouring pipe (3).

2. The method for reinforcing the top of the seepage-proof wall according to claim 1, characterized in that: The elevation preset height in step S2 is the switching height, which is 2.0 meters to 6.0 meters.

3. The method for reinforcing the top of the seepage-proof wall according to claim 1, characterized in that: In step S3, the extended casting conduit (3) is made of one or more sections.

4. The method for reinforcing the top of the seepage-proof wall according to claim 3, characterized in that: The extended pouring pipe (3) is connected to the original pipe embedded in the concrete and the two adjacent extended pouring pipes (3) by a special connector.

5. The method for reinforcing the top of the seepage-proof wall according to claim 4, characterized in that: The top of the extended pouring pipe (3) at the top is a certain height above the construction ground. This height is: H_extended. Through H_extended, the concrete liquid in the extended pouring pipe (3) forms the minimum effective head that meets the quality requirements: Δh_min.

6. The method for reinforcing the top of the seepage-proof wall according to claim 5, characterized in that: A concrete level detector (6) is installed inside the top of the extended pouring pipe (3) at the top.

7. The method for reinforcing the top of the seepage-proof wall according to claim 5, characterized in that: The delivery pump pipe (2) extends 0.5 meters into the top of the uppermost extended pouring pipe (3).

8. The method for reinforcing the top of the seepage-proof wall according to claim 6, characterized in that: The distance between the installation position of the concrete liquid level detector (6) and the top of the uppermost extended pouring pipe (3) is less than 0.5 meters.

9. The method for reinforcing the top of the seepage-proof wall according to claim 6, characterized in that: The concrete level in the extended pouring pipe (3) is monitored in real time by a concrete level detector (6).

10. The method for reinforcing the top of the seepage-proof wall according to claim 5, characterized in that: The liquid level difference Δh ≥ the minimum effective head Δh_min.

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