Prefabricated heat preservation nodular cast iron jacking pipe thermal compensation structure and construction method

Abstract

The invention discloses a thermal compensation structure of a prefabricated heat preservation nodular cast iron pipe jacking and a construction method, and relates to the technical field of pipe jacking construction, the structure comprises a thermal compensation unit arranged between two adjacent sections of prefabricated heat preservation nodular cast iron pipes, and the thermal compensation unit is composed of a connecting pipe, a transition sleeve and a detachable temporary bearing piece; axial sliding sealing fit is formed between the transition sleeve and the connecting pipe and between the transition sleeve and the adjacent prefabricated heat preservation nodular cast iron pipe. The construction method comprises the steps that the prefabricated heat preservation nodular cast iron pipes are jacked section by section, the thermal compensation units are arranged according to the preset intervals, and the temporary jacking piece is dismantled to form thermal compensation fit after jacking is completed. The problem that axial thermal elongation can not be smoothly released in the operation stage of the whole pipeline can be solved, various potential safety hazards of the pipeline are avoided, and stable and safe operation of the pipeline is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of pipe jacking construction technology, specifically to a prefabricated insulated ductile iron pipe jacking thermal compensation structure and construction method. Background Technology

[0002] While prefabricated insulated ductile iron pipes possess a certain degree of self-compensation for thermal expansion and contraction, during pipe jacking construction, the jacking force tightens the socket structures of the previously jacked sections when the next section is jacked in. This squeezes out the pre-reserved gaps between pipe sections used for self-compensation. Even if small gaps remain after construction, these gaps are insufficient in size and unstable in condition, failing to meet thermal compensation requirements. During the entire pipeline operation phase, the axial thermal expansion caused by temperature changes cannot be released due to the lack of effective compensation space. After prolonged use, the pipeline is prone to axial thermal stress, leading to safety hazards such as pipe section bending, joint leakage, and pipe body fracture, seriously affecting operational stability. Currently, no reliable solution to this problem has been developed. Summary of the Invention

[0003] To address the problems mentioned above, this invention provides a prefabricated insulated ductile iron jacking pipe thermal compensation structure and construction method.

[0004] The technical solution of the present invention is as follows: A prefabricated insulated ductile iron jacking pipe thermal compensation structure includes a thermal compensation unit disposed between two adjacent prefabricated insulated ductile iron pipe sections. The thermal compensation unit includes a connecting pipe, a transition sleeve, and a temporary jacking component.

[0005] Specifically, the connecting pipe is located between two adjacent prefabricated insulated ductile iron pipe sections, the transition sleeve is sleeved on the outside of the connecting pipe, and the temporary support is detachably installed between the connecting pipe and the adjacent prefabricated insulated ductile iron pipe. Furthermore, the transition sleeve and the connecting pipe, as well as the transition sleeve and the adjacent prefabricated insulated ductile iron pipe, are all provided with a sealing fit structure that can form axial sliding.

[0006] In the aforementioned thermal compensation unit, preferably, the temporary support component is a split-type annular structure, with the opposite ends of the connecting pipe and the adjacent prefabricated insulated ductile iron pipe respectively abutting against the two ends of the temporary support component, and a gap is reserved between the temporary support component and the inner wall of the transition sleeve for the insertion of the adjustment component.

[0007] Furthermore, the temporary support component includes a support flange, protective gaskets, and bolt assemblies. Two protective gaskets are located at both ends of the support flange, and the bolt assemblies pass through and connect the support flange and the two protective gaskets.

[0008] Furthermore, two support flanges are provided opposite each other, and a sleeve is provided between the two support flanges, with the sleeve fitted onto the outside of the bolt of the bolt assembly.

[0009] In the aforementioned thermal compensation unit, preferably, the transition sleeve is a double-socket sleeve, with the socket structures at both ends forming a sealing fit with the outer wall of the connecting pipe and the outer wall of the adjacent prefabricated insulated ductile iron pipe, respectively.

[0010] In the aforementioned thermal compensation unit, more preferably, the connecting pipe is a double-insertion top pipe, and the inlet structures at both ends of the pipe form a sealing fit with the socket of the adjacent pre-insulated ductile iron pipe and the socket of the transition sleeve, respectively.

[0011] This invention also provides a construction method for using the above-mentioned prefabricated insulated ductile iron jacking pipe thermal compensation structure, characterized by comprising the following steps: S1: Carry out pipe jacking construction, and jack in prefabricated insulated ductile iron pipes section by section; S2: Install thermal compensation units between adjacent sections of prefabricated insulated ductile iron pipe at preset intervals. The installation of the thermal compensation units specifically includes: S2.1: Install the connecting pipe to achieve a sealed fit between the jacking end of the connecting pipe and the prefabricated insulated ductile iron pipe that has been jacked in the previous section; S2.2: The transition sleeve is fitted onto the outside of the connecting pipe; S2.3: Install a temporary support at the end of the connecting pipe to be jacked in; S2.4: After jacking in one section of prefabricated insulated ductile iron pipe, a sealed fit is achieved between it and the jacking end of the transition sleeve, and the temporary support is pressed against the end of the connecting pipe through the jacking end; S3: Repeat steps S1 and S2. After the entire jacking pipeline is installed, remove all temporary support components in the thermal compensation unit to ensure that axial sliding thermal compensation fit is formed between the transition sleeve and the connecting pipe, and between the transition sleeve and the adjacent prefabricated insulated ductile iron pipe.

[0012] In the above-mentioned construction method of thermal compensation structure, preferably, the thermal compensation amount of the pipeline between two adjacent thermal compensation units is calculated according to the following formula: Lb=α×Lo×ΔT×K; Where α is the linear expansion coefficient of the prefabricated insulated ductile iron pipe, Lo is the pipeline length between two adjacent thermal compensation units, ΔT is the preset temperature difference, and K is the safety factor.

[0013] More preferably, the safety factor K ranges from 1.2 to 1.5.

[0014] In the above construction method for thermal compensation structure, preferably, the preset spacing in step S1 is 50m-70m.

[0015] The prefabricated insulated ductile iron jacking pipe thermal compensation structure and construction method proposed in this invention solves the problems in existing pipe jacking construction where the jacking force easily squeezes out the reserved thermal compensation gap between pipe sections, or the gap size is insufficient or unstable, failing to meet thermal compensation requirements. This ensures smooth release of axial thermal elongation throughout the pipeline's operation, avoiding safety hazards such as pipe section bending, joint leakage, and pipe body breakage, thus guaranteeing stable and safe pipeline operation. Currently, no domestic manufacturer has developed a similar thermal compensation structure and construction method to solve these problems. Attached Figure Description

[0016] The solutions and advantages of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0017] In the attached diagram: Figure 1 This is a half-sectional view of a prefabricated insulated ductile iron jacking pipe thermal compensation structure in this embodiment; Figure 2 for Figure 1 Enlarged structural diagram of the temporary support component; The components represented by the various reference numerals in the diagram are: 1. First prefabricated insulated ductile iron pipe; 2. Connecting pipe; 3. Temporary support component; 31. Support flange; 32. Protective gasket; 33. Bolt assembly; 34. Sleeve; 35. Rubber sheet; 4. Transition sleeve; 5. Second prefabricated insulated ductile iron pipe. Detailed Implementation

[0018] Example 1: A prefabricated insulated ductile iron jacking pipe thermal compensation structure like Figure 1 As shown, the prefabricated insulated ductile iron jacking pipe thermal compensation structure of this embodiment includes a thermal compensation unit disposed between two adjacent prefabricated insulated ductile iron pipe sections. The thermal compensation unit includes a connecting pipe 2, a transition sleeve 4, and a temporary support component 3.

[0019] The two prefabricated insulated ductile iron pipes are the first prefabricated insulated ductile iron pipe 1 and the second prefabricated insulated ductile iron pipe 5, which are jacked in sequentially. The connecting pipe 2 is located between the first prefabricated insulated ductile iron pipe 1 and the second prefabricated insulated ductile iron pipe 5. The transition sleeve 4 is sleeved on the outside of the connecting pipe 2. The temporary support 3 is detachably installed between the connecting pipe 2 and the second prefabricated insulated ductile iron pipe 5 to maintain the preset gap between the connecting pipe 2 and the second prefabricated insulated ductile iron pipe 5 during the pipe jacking construction stage. The transition sleeve 4 and the connecting pipe 2, as well as the transition sleeve 4 and the second prefabricated insulated ductile iron pipe 5, are all designed with a sealing fit structure that can form axial sliding.

[0020] Specifically, the connecting pipe 2 is a double-insertion jacking pipe with inlet structures at both ends, and the transition sleeve 4 is a double-socket sleeve with socket structures at both ends.

[0021] One end of the connecting pipe 2 forms a sealed fit with the socket of the first pre-insulated ductile iron pipe 1, and the other end forms a sealed fit with the socket of one end of the transition sleeve 4. The other end of the transition sleeve 4 forms a sealed fit with the socket of the second pre-insulated ductile iron pipe 5. Through multiple sets of socket fits, a pipeline with good sealing performance is formed between the first pre-insulated ductile iron pipe 1, the connecting pipe 2, the transition sleeve 4, and the second pre-insulated ductile iron pipe 5. All of the above sealing fits are achieved by rubber sealing rings, which are embedded in the sealing grooves of each socket, which can further enhance the sealing reliability.

[0022] To facilitate disassembly and assembly, the temporary support component 3 adopts a split ring structure. Specifically, it can be set as a three-section structure with an equal central angle of 60 degrees, or a four-section structure with an equal central angle of 45 degrees. After disassembly, it can be easily installed and removed from the gap between the transition sleeve 4 and the connecting pipe 2.

[0023] The opposite ends of the connecting pipe 2 and the second prefabricated insulated ductile iron pipe 5 abut against the two ends of the temporary support 3, and a gap is reserved between the temporary support 3 and the inner wall of the transition sleeve 4 for the insertion of the adjustment component. The core function of the temporary support 3 is to accurately maintain the preset gap between the connecting pipe 2 and the second prefabricated insulated ductile iron pipe 2 during the pipe jacking construction stage. After the temporary support 3 is removed after the construction is completed, the preset gap can provide sufficient space for the axial sliding between the transition sleeve 4 and the connecting pipe 2, and between the transition sleeve 4 and the second prefabricated insulated ductile iron pipe 2, thereby ensuring the realization of the thermal compensation function.

[0024] Furthermore, the minimum axial distance between the two sockets of the transition sleeve 4 is greater than the sum of the axial sliding distance between the transition sleeve 4 and the connecting pipe 2 and the axial sliding distance between the transition sleeve 4 and the second pre-insulated ductile iron pipe 5. This ensures that the socket structure at both ends of the transition sleeve 4 maintains a sealed fit with the outer wall of the connecting pipe 2 and the outer wall of the second pre-insulated ductile iron pipe 5 throughout the entire service life of the pipeline, and will not slide into the sliding gap between the connecting pipe 2 and the second pre-insulated ductile iron pipe 5, thus ensuring the pipeline's sealing performance for a long time.

[0025] To facilitate adjustment of the position and clamping force of the temporary support 3 during installation, a gap is reserved between the temporary support 3 and the inner wall of the transition sleeve 4 for the insertion of an adjustment component. In this embodiment, the adjustment component is a multi-segment arc-shaped rubber sheet 35 with the same radius. By inserting arc-shaped rubber sheets 35 of different numbers or thicknesses into the gap, the radial position of the temporary support 3 can be finely adjusted to ensure that its axial end faces are tightly abutted against the opposite end faces of the connecting pipe 2 and the second prefabricated insulated ductile iron pipe 5.

[0026] like Figure 2 As shown, the temporary support member 3 includes a support flange 31 and a protective gasket ring 32 with a split annular structure, as well as a bolt assembly 33 connecting the two.

[0027] Two protective gaskets 32 are provided opposite to each other and are respectively fitted to the axial ends of the support flange 31 to avoid direct contact between the support flange 31 and the end faces of the connecting pipe 2 and the second prefabricated insulated ductile iron pipe 5, which would cause wear. The bolt assembly 33 includes a screw and a nut, which passes through the support flange 31 and the two protective gaskets 32. The support flange 31 and the protective gaskets 32 are detachably connected by tightening the nut. The temporary support component 3 is fixed by inserting an adjusting piece into the gap between the outer wall of the temporary support component 3 and the inner wall of the transition sleeve 4.

[0028] Two support flanges 31 are provided opposite each other, and a sleeve 34 is provided between the two support flanges 31. The sleeve 34 is fitted on the outside of the screw between the two support flanges 31. The two support flanges 31 are symmetrically arranged and, together with the sleeve 34, form a rigid force-bearing structure, which can evenly distribute the jacking force and avoid local stress concentration that could lead to structural deformation, thereby ensuring the stability of the pipeline during the jacking process.

[0029] Example 2: Construction method of a prefabricated insulated ductile iron jacking pipe thermal compensation structure The construction method in this embodiment applies the thermal compensation structure of Embodiment 1, combined with... Figure 1 Specifically, it includes the following steps: S1: Conduct pipe jacking construction, using a pipe jacking machine to jack up prefabricated insulated ductile iron pipes section by section, ensuring that the deviation of the pipeline axis meets the design requirements during the jacking process.

[0030] S2: Install thermal compensation units between adjacent sections of prefabricated insulated ductile iron pipe at preset intervals. Typically, one set of thermal compensation units needs to be installed every 50m-70m. This embodiment uses the most common 60m interval. The specific installation work includes: S2.1: Install the connecting pipe 2, insert the inlet end of the connecting pipe 2 into the socket of the first prefabricated insulated ductile iron pipe 1 that has been jacked up in the previous section, and ensure that the inlet end of the connecting pipe 2 and the socket of the first prefabricated insulated ductile iron pipe 1 are sealed together by the rubber sealing ring.

[0031] S2.2: The transition sleeve 4 is sleeved on the outside of the connecting pipe 2 from the end to be jacked in, so that the socket of one end of the transition sleeve 4 is sealed and not tightly fitted with the insertion port of the end to be jacked in of the connecting pipe 2, leaving operating space for the subsequent installation of the temporary support 3.

[0032] S2.3: Install a temporary support at the jacking end of connecting pipe 2: First, assemble the supporting flange 31 and protective gasket 32 ​​of the temporary support component 3 into a split ring structure using bolt assembly 33. Then, install each of its separate parts in sequence at the gap between the transition sleeve 4 and the connecting pipe 2. Next, insert an arc-shaped rubber sheet 35 into the gap between the outer wall of the temporary support component 3 and the inner wall of the transition sleeve 4. Fix the temporary support component 3 by adjusting the number of arc-shaped rubber sheets 35, while ensuring that the jacking end of the temporary support component 3 is tightly fitted with the end face of the connecting pipe 2.

[0033] S2.4: Start the pipe jacking machine to jack up the second prefabricated insulated ductile iron pipe 5 after it has been jacked up, so that the jacking end of the second prefabricated insulated ductile iron pipe 5 comes into contact with the jacking end of the temporary support 3, and continue jacking up until the spigot of the second prefabricated insulated ductile iron pipe 5 is sealed with the socket of the jacking end of the transition sleeve 4. At this time, the second prefabricated insulated ductile iron pipe 5 transmits the jacking force to the first prefabricated insulated ductile iron pipe 1 through the temporary support 3, effectively maintaining the stability of the pipeline.

[0034] S3: Repeat steps S1 and S2 until the entire jacking pipeline is installed. Then, remove the temporary support components 3 in all thermal compensation units by pulling out the arc-shaped rubber sheet 35 and loosening the nuts of the bolt assembly 33. At this time, axial sliding thermal compensation fits are formed between the transition sleeve 4 and the connecting pipe 2, and between the transition sleeve 4 and the adjacent prefabricated insulated ductile iron pipe, in order to cope with the thermal expansion and contraction deformation of the pipeline.

[0035] In this embodiment, the axial length of the transition sleeve 4 is calculated based on the principle of prioritizing thermal compensation requirements while also considering construction operations, as detailed below: First, calculate the thermal compensation amount Lb between two adjacent thermal compensation units: Lb = α × Lo × ΔT × K, where α is the linear expansion coefficient of the prefabricated insulated ductile iron pipe, Lo is the pipeline length between two adjacent thermal compensation units, ΔT is the preset temperature difference, and K is the safety factor.

[0036] Then, determine the minimum length Ls of the transition sleeve to meet the construction operation requirements. This dimension is adjusted according to the specific pipe diameter or construction conditions, and there is no specific limitation.

[0037] Finally, the axial length of the transition sleeve is determined to be L=max(Lb, Ls), that is, the larger value between the heat compensation amount Lb and the minimum length of construction operation Ls is taken to ensure that both the heat compensation requirements are met and the specific construction practice is followed.

[0038] Based on actual field verification, in conventional heating pipeline network projects with dimensions of DN800-DN1600, the minimum value of Ls is 800mm, the commonly used safety factor K ranges from 1.2 to 1.5, and the preset spacing in step S1 is usually 50m-70m.

[0039] A specific and commonly used example is: Given that the coefficient of linear expansion of a pre-insulated ductile iron pipe is α = 11.8 × 10⁻⁶. -6 / ℃, the pipeline length between two adjacent thermal compensation units is selected as the median value Lo=60m, the preset temperature difference is selected as ΔT=40℃ based on the local minimum winter temperature of -10℃ and maximum summer medium temperature of 30℃, and the safety factor is selected as the median value K=1.3. Then the thermal compensation amount of the pipeline between two adjacent thermal compensation units is Lb=11.8×10 -6 / ℃×60m×40℃×1.3≈36.8mm. According to the formula L=max(36.8mm, 800mm), the transition sleeve with an axial length of 800mm is finally selected, which can meet both the heat compensation requirements and the specific construction requirements.

Claims

1. A prefabricated insulated ductile iron jacking pipe thermal compensation structure, characterized in that, This includes a thermal compensation unit installed between two adjacent prefabricated insulated ductile iron pipe sections; The thermal compensation unit includes a connecting pipe (2), a transition sleeve (4) and a temporary support component (3). The connecting pipe (2) is located between two adjacent prefabricated insulated ductile iron pipe sections, and the transition sleeve (4) is sleeved on the outside of the connecting pipe (2). The temporary support member (3) is detachably installed between the connecting pipe (2) and the adjacent prefabricated insulated ductile iron pipe, and the transition sleeve (4) and the connecting pipe (2), and the transition sleeve (4) and the adjacent prefabricated insulated ductile iron pipe are both provided with a sealing fit structure that can form an axial sliding.

2. The prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 1, characterized in that, The temporary support component (3) is a split-type ring structure; The opposite ends of the connecting pipe (2) and the adjacent prefabricated insulated ductile iron pipe respectively abut against the two ends of the temporary support (3), and a gap is reserved between the temporary support (3) and the inner wall of the transition sleeve (4) for the insertion of the adjustment component.

3. The prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 2, characterized in that, The temporary support component (3) includes a support flange (31), a protective gasket (32), and a bolt assembly (33). The protective gaskets (32) are provided at both ends of the support flange (31), and the bolt assembly (33) passes through and connects the support flange (31) and the two protective gaskets (32).

4. The prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 3, characterized in that, Two support flanges (31) are provided opposite each other, and a sleeve (34) is provided between the two support flanges (31). The sleeve (34) is sleeved on the outside of the bolt of the bolt assembly (33).

5. The prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 1, characterized in that, The transition sleeve (4) is a double-socket sleeve, and the socket structures at both ends of the sleeve form a sealing fit with the outer wall of the connecting pipe (2) and the outer wall of the adjacent prefabricated insulated ductile iron pipe, respectively.

6. The prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 5, characterized in that, The connecting pipe (2) is a double-insertion top pipe, and the inlet structures at both ends of the pipe form a sealed fit with the socket of the adjacent prefabricated insulated ductile iron pipe and the socket of the transition sleeve (4).

7. A construction method for using a prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Carry out pipe jacking construction, and jack in prefabricated insulated ductile iron pipes section by section; S2: Heat compensation units are installed between adjacent sections of prefabricated insulated ductile iron pipe at preset intervals. The installation of the heat compensation units specifically includes: S2.1: Install the connecting pipe (2) so that the jacking end of the connecting pipe (2) is sealed to the prefabricated insulated ductile iron pipe that has been jacked in the previous section; S2.2: The transition sleeve (4) is fitted onto the outside of the connecting tube (2); S2.3: Install a temporary support (3) at the end of the connecting pipe (2) to be jacked in; S2.4: After jacking in one section of prefabricated insulated ductile iron pipe, make it seal with the jacking end of the transition sleeve (4), and press the temporary support (3) against the pipe end of the connecting pipe (2) through the jacking end; S3: Repeat S1 and S2. After the entire jacking pipeline is installed, remove the temporary support components (3) in all thermal compensation units so that the transition sleeve (4) and the connecting pipe (2) and the transition sleeve (4) and the adjacent prefabricated insulated ductile iron pipe can form an axial sliding thermal compensation fit.

8. The construction method of a prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 7, characterized in that, The heat compensation amount Lb for the pipeline between two adjacent heat compensation units is calculated using the following formula: Lb = α × Lo × ΔT × K; Where α is the linear expansion coefficient of the prefabricated insulated ductile iron pipe, Lo is the pipeline length between two adjacent thermal compensation units, ΔT is the preset temperature difference, and K is the safety factor.

9. The construction method of a prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 8, characterized in that, The safety factor ranges from 1.2 to 1.

5.

10. The construction method of a prefabricated insulated ductile iron jacking pipe thermal compensation structure as described in claim 7, characterized in that, The preset spacing in step S1 is 50m-70m.

Images