Roller compacted concrete dam cooling water pipe damage prevention and displacement construction method

Abstract

The present application relates to the field of temperature control of roller compacted concrete dam, in particular to a kind of roller compacted concrete dam cooling water pipe damage prevention and displacement construction method.It includes the following steps:S1, when pouring to design pre-burying cooling water pipe elevation, the layer is carried out static rolling treatment;S2, setting out the layout line type and specific position of cooling water pipe and marking with lime;S3, rubber stick is laid according to the position and line type of cooling water pipe setting;S4, static rolling compaction, rubber stick is pressed into the layer concrete, and U-shaped nail and rubber stick are taken out after rolling compaction;S5, cooling pipe is laid along the pipe groove left by rubber stick;S6, after cooling pipe laying is completed, the next layer of roller compacted concrete construction is carried out.The present application carries out groove processing in advance when laying cooling water pipe layer, then lays cooling pipe in the groove, can effectively prevent the disturbance, extrusion and damage of roller compacted concrete material and construction equipment to cooling water pipe, greatly improves the laying precision and intact rate of cooling water pipe.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology for roller-compacted concrete dams, and in particular to a construction method for preventing damage and relocation of cooling water pipes in roller-compacted concrete dams. Background Technology

[0002] Roller-compacted concrete (RCC) is dry-hard concrete compacted by a vibratory roller. It features high strength, thin-layer construction, rapid compaction, and large-area construction, which is beneficial for improving construction efficiency, shortening the construction period, and reducing investment. However, temperature control and crack prevention in dams has always been a major technical challenge. Common temperature control measures mainly include the selection of raw materials, temperature control at the outlet of the machine, temperature control during transportation and pouring, water cooling, and surface protection. Among these, HDPE plastic water pipe cooling is widely used both domestically and internationally due to its great adaptability and flexibility. It is the most common and direct means of internal temperature control for roller-compacted concrete dams. The quality of the cooling water pipe laying directly affects the temperature control and crack prevention effect of the dam and the overall quality of the dam.

[0003] Currently, the construction process and method for cooling water pipes in roller-compacted concrete (RCC) construction is as follows: static leveling of the already compacted surface → laying of cooling water pipes → joint connection → anchor bar fixing → covering with the next layer of material → compaction. This method involves directly laying the pipes on the already compacted surface, anchoring them with anchor bars, and then covering them with RCC. This construction method has the following drawbacks: 1. The use of equipment such as dump trucks, leveling machines, and vibratory rollers can easily cause displacement, stress deformation, and shear damage to the cooling water pipes; 2. During unloading, leveling, and compaction of concrete, coarse aggregates can easily roll onto the cooling water pipes. During leveling and compaction, large-diameter aggregates can easily puncture, squeeze, or bend the cooling water pipes, causing leaks, reduced flow capacity, or even blockages; 3. After the cooling water pipes are displaced, positioning the drainage holes, grouting holes, and inspection holes during subsequent RCC construction becomes difficult, and the drill rod can easily damage the cooling water pipes. Summary of the Invention

[0004] The purpose of this invention is to address the problem that cooling water pipes are prone to displacement, compression, and damage after installation in the prior art, and to propose a construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams.

[0005] The technical solution of the present invention: a construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams, comprising the following steps: S1. Layer treatment: Layered roller compaction of concrete. When the concrete is poured to the elevation of the pre-embedded cooling water pipe, the layer that has been compacted is subjected to static rolling treatment to ensure that the surface is flat and compacted. S2. Positioning and layout: Lay out the layout line and specific location of the cooling water pipes according to the construction drawings and mark them with white lime. S3. Rubber sheet laying: Prefabricated rubber rods are divided into two types: U-shaped and straight. The diameter of the rubber rod is the same as the diameter of the pre-embedded cooling water pipe. The opening spacing of the U-shaped rubber rod is consistent with the transverse spacing of the cooling pipe circuit. The rubber rods are laid according to the position and line of the cooling water pipe layout. S4. Grooving: After the rubber rods are laid, they are pressed into the concrete layer by static rolling with a road roller. After rolling, the U-shaped nails and rubber rods are removed. S5. Laying cooling pipes: Lay the cooling pipes along the grooves left by the rubber rods and anchor them with U-shaped nails. Cover and protect the pipe ends that protrude from the concrete. S6. Concrete paving and compaction: After the cooling pipes are laid, the next layer of roller-compacted concrete is constructed, and the roller-compacted concrete is paved and compacted in layers.

[0006] Preferably, in S3, U-shaped nails are used for anchoring at every 2m interval and at the port position.

[0007] Preferably, in step S4, the removed U-shaped nails and rubber rods are cleaned for subsequent compaction, and the groove surface is cleaned with a brush. The entire grooving process should be completed before the concrete at this level sets.

[0008] Preferably, in S5, the cooling pipes are laid from downstream to upstream along the compaction strips according to the roller-compacted concrete construction, without crossing the dam section.

[0009] Preferably, in S5, the interfaces of two adjacent cooling pipe sections are connected using a heat fusion joint.

[0010] Preferably, in S6, the cooling pipe is in a water-flow state during the unloading and compaction process, with a water pressure of not less than 0.8 MPa, so as to reduce the pressure difference between the inside and outside of the pipe.

[0011] Preferably, the water temperature through the cooling pipe is set according to the concrete temperature, and the temperature difference between the two should not exceed 20°C to prevent micro-cracks around the cooling pipe.

[0012] Compared with the prior art, the present invention has the following beneficial technical effects: by pre-treating the cooling water pipe laying layer according to the layout position, and then laying the cooling water pipe in the trench, it can effectively prevent the disturbance, squeezing and damage of the cooling water pipe by the compacted concrete material and construction equipment, and greatly improve the laying accuracy and integrity rate of the cooling water pipe. Attached Figure Description

[0013] Figure 1 Plan layout for cooling pipe installation; Figures 2-4 Diagram showing the construction process of embedding cooling pipes in the groove of a rubber rod. Detailed Implementation

[0014] Example 1; as Figures 1-4 As shown, the present invention proposes a construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams, comprising the following steps: S1. Layer treatment: Layered roller compaction of concrete. When the concrete is poured to the elevation of the pre-embedded cooling water pipe, the layer that has been compacted is subjected to static rolling treatment to ensure that the surface is flat and compacted. If the layer is soft and brittle, or if the surface is churning, it is treated locally and then statically rolled again. During high temperature periods, the surface loses water and hardens quickly. Spraying to keep it moist can be used to extend the workable time. S2. Positioning and layout: Using a total station and measuring tape, lay out the layout line and specific location of the cooling water pipes according to the construction drawings and mark them with white lime. S3. Rubber Sheet (PE Rod) Laying: PE rod is a highly crystalline, non-polar thermoplastic material with good chemical stability, as well as high rigidity, toughness, and mechanical strength. PE rods are prefabricated by professional manufacturers according to actual needs. Generally, two sets of 3-5 cooling water pipe circuit lengths are prefabricated, which can be recycled during construction. The prefabricated rubber rods are divided into U-shaped and straight types. The diameter of the rubber rod is the same as the diameter of the pre-embedded cooling water pipe. The opening spacing of the U-shaped rubber rod is consistent with the lateral spacing of the cooling pipe circuit. The rubber rods are laid according to the layout position and line of the cooling water pipe. S4. Grooving: After the rubber rods are laid, they are pressed into the concrete layer by static rolling with a road roller. If the rubber rods deviate significantly from the anchoring position during rolling, they should be corrected in time and the grooves should be re-pressed. After rolling, the U-shaped nails and rubber rods are removed. S5. Laying Cooling Pipes: Lay the cooling pipes along the grooves left by the rubber rods and anchor them with U-shaped nails to prevent displacement of the pipes during subsequent compaction. Cover and protect the pipe ends that protrude from the concrete. After the pipes are laid, conduct a water flow test to check for blockages or leaks. Create images and records of the circuit numbers, coordinates, elevations, and joint locations. Adjust the drilling distances before drilling drainage holes, grouting holes, and inspection holes to avoid these locations, and predict pipe positions in the drilling area. S6. Concrete paving and compaction: After the cooling pipes are laid, the next layer of roller-compacted concrete is constructed. The roller-compacted concrete is paved and compacted in layers. When pouring to the next layer of cooling system control layer, the cooling pipes are arranged in the same way.

[0015] Example 2; as Figures 1-4As shown, this invention proposes a construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams. Compared to Embodiment 1, this embodiment provides supplementary descriptions of each step. Specifically, in S3, U-shaped nails are used for anchoring at 2m intervals and at the port positions to prevent displacement of the rubber rods during the grooving process. In S4, the removed U-shaped nails and rubber rods are cleaned for subsequent rolling, and the groove surface is cleaned with a brush. The entire grooving process should be completed before the concrete at this level sets to prevent ineffective grooving. In S5, when laying HDPE polyethylene cooling pipes, the process proceeds from downstream to upstream along the rolling strips according to the roller-compacted concrete construction, without crossing dam sections. The joints of adjacent cooling pipe sections are connected using a heat-fusion joint. After the joints cool, a visual inspection is performed, requiring uniform flanges and no misalignment. In S6, the cooling pipes are in a water-flow state during the unloading and compaction process, with a water pressure of not less than 0.8MPa, in order to reduce the pressure difference between the inside and outside of the pipes. The water temperature passing through the cooling pipes is set according to the concrete temperature, and the temperature difference between the two should not exceed 20℃ to prevent micro-cracks around the cooling pipes.

[0016] In summary, this invention pre-treats the cooling water pipes according to the marked positions before laying them, and then lays the cooling water pipes within the trenches. This effectively prevents disturbance, compression, and damage to the cooling water pipes caused by compacted concrete materials and construction equipment, significantly improving the laying accuracy and integrity of the cooling water pipes. The technical solution of this invention has been successfully applied in the Heihe Huangzangsi Hydropower Project, demonstrating excellent practical results. It effectively prevents disturbance to the cooling water pipes by compaction equipment and improves the laying accuracy of the cooling water pipes.

[0017] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams, characterized in that, Includes the following steps: S1. Layer treatment: Layered roller compaction of concrete. When the concrete is poured to the elevation of the pre-embedded cooling water pipe, the layer that has been compacted is subjected to static rolling treatment to ensure that the surface is flat and compacted. S2. Positioning and layout: Lay out the layout line and specific location of the cooling water pipes according to the construction drawings and mark them with white lime. S3. Rubber sheet laying: Prefabricated rubber rods are divided into two types: U-shaped and straight. The diameter of the rubber rod is the same as the diameter of the pre-embedded cooling water pipe. The opening spacing of the U-shaped rubber rod is consistent with the transverse spacing of the cooling pipe circuit. The rubber rods are laid according to the position and line of the cooling water pipe layout. S4. Grooving: After the rubber rods are laid, they are pressed into the concrete layer by static rolling with a road roller. After rolling, the U-shaped nails and rubber rods are removed. S5. Laying cooling pipes: Lay the cooling pipes along the grooves left by the rubber rods and anchor them with U-shaped nails. Cover and protect the pipe ends that protrude from the concrete. S6. Concrete paving and compaction: After the cooling pipes are laid, the next layer of roller-compacted concrete is constructed, and the roller-compacted concrete is paved and compacted in layers.

2. The construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams according to claim 1, characterized in that, In S3, U-shaped nails are used for anchoring at every 2m interval and at the port position.

3. The construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams according to claim 1, characterized in that, In S4, the removed U-shaped nails and rubber rods are cleaned for subsequent compaction, and the groove surface is cleaned with a brush. The entire grooving process should be completed before the concrete at this level sets.

4. The construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams according to claim 1, characterized in that, In S5, the cooling pipes are laid from downstream to upstream along the compaction strips, depending on the roller-compacted concrete construction, and do not cross the dam section.

5. The construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams according to claim 1, characterized in that, In S5, the interfaces of two adjacent cooling pipe sections are connected using a heat fusion joint.

6. The construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams according to claim 1, characterized in that, In S6, the cooling pipes are in a water-flow state during the unloading and compaction process, with a water pressure of not less than 0.8MPa, in order to reduce the pressure difference between the inside and outside of the pipes.

7. The construction method for preventing damage and displacement of cooling water pipes in roller-compacted concrete dams according to claim 6, characterized in that, The water temperature through the cooling pipes is set according to the concrete temperature, and the temperature difference between the two should not exceed 20°C to prevent micro-cracks around the cooling pipes.

Images