Construction method for pipeline relocation and special-shaped steel casing used for same

Abstract

The invention discloses a construction method for pipeline relocation and a special-shaped steel casing used for the method. The method comprises the steps that a corresponding special-shaped steel casing is manufactured according to the diameter size of an underground pipeline to be relocated, and vibration sinking parameters of the special-shaped steel casing are determined; the trend of the underground pipeline to be relocated is accurately positioned; sequentially vibrating and sinking the special-shaped steel casing; according to the MJS reinforcement design scheme, pit bottom foundation reinforcement is conducted; earth excavation is conducted in the special-shaped steel pile casing; performing cutover relocation on the underground pipeline to be relocated; and the special-shaped steel pile casing is cut, pulled out and recycled from bottom to top in a blocked and segmented mode. The special-shaped steel casing comprises a first steel casing assembly and a second steel casing assembly, wherein the first steel casing assembly is connected with the second steel casing assembly. According to the method, the large-diameter deeply-buried underground pipeline can be changed, smooth change of the pipeline can be safely, high-efficiently ensured in a high-quality mode, and good economic benefits and social benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of construction machinery technology, and in particular to a construction method for pipeline relocation and a special-shaped steel casing used in this method. Background Technology

[0002] To effectively address the shortage of urban land and promote the intensive use of land resources, the development of underground space resources has become a crucial task for many large and medium-sized cities. Pipeline relocation is a key and challenging aspect of urban underground space resource development, especially for large-diameter pipelines buried at deep depths in soft soil conditions. As is well known, most coastal areas of my country are characterized by silty soft soil layers. Silty soft soil has poor engineering properties, exhibiting typical "five highs and two lows" characteristics: high water content, high rheological properties, high void ratio, high compressibility, high sensitivity, low permeability, and low strength. For the relocation of large-diameter, deeply buried underground pipelines, safely excavating and relocating the pipeline becomes a significant challenge. In silty soft soil environments, shallow excavation depths can be achieved using methods such as tensile steel plates and PC steel pipe piles for retaining walls, typically less than 3 meters. Deeper excavation depths often employ continuous underground reinforcement with internal bracing. However, due to the shape of the underground pipeline and the form of the enclosure structure, none of the above enclosure methods can completely expose the underground pipeline and cannot provide a safe and reliable pipeline cutting and splicing working surface. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a construction method for pipeline relocation and an irregularly shaped steel casing for the method. Engineering practice has proven that using the method and apparatus of the present invention for the relocation of large-diameter, deeply buried underground pipelines can ensure the smooth relocation of pipelines safely, efficiently, and with good economic and social benefits, achieving unexpected technical effects.

[0004] To achieve the above objectives, according to one aspect of the present invention, a construction method for pipeline relocation is provided, comprising: fabricating a corresponding irregularly shaped steel casing according to the diameter of the underground pipeline to be relocated, and determining its vibration and settling parameters; accurately locating the route of the underground pipeline to be relocated; sequentially vibrating and settling the irregularly shaped steel casing; reinforcing the foundation at the bottom of the pit according to the MJS reinforcement design scheme; excavating earthwork inside the irregularly shaped steel casing; relocating the underground pipeline to be relocated by cutting and splicing; and removing and recovering the irregularly shaped steel casing by cutting and splicing from bottom to top in sections, wherein the irregularly shaped steel casing includes at least a first steel casing assembly and a second steel casing assembly, the first steel casing assembly being connected to the second steel casing assembly, the cross-section of the irregularly shaped steel casing being circular, and the bottom of the irregularly shaped steel casing being made into an arched tongue-and-groove shape.

[0005] Optionally, positioning holes are set at equal intervals and symmetrically according to the intersection plane position of the arched tongue and groove of the irregular steel casing and the underground pipeline to be relocated, so as to detect the direction of the underground pipeline to be relocated.

[0006] Optionally, the first steel casing assembly is a single-section arched tongue-and-groove steel casing, and the second steel casing assembly is a single or multiple sections of standard steel casing.

[0007] Optionally, according to the marked direction and position, arched tongue and groove steel casings are placed, and the arched tongue and groove steel casings and standard section steel casings are sunk in sequence until they are all sunk.

[0008] Optionally, after the core sampling of the pile foundation passes the test, the earthwork is excavated in the narrow space of the irregular steel casing until the bottom of the pit is reached, and then the bottom is sealed to create a safe and full-scale cutting and splicing working space.

[0009] Optionally, the arched tongue and groove of the arched tongue and groove steel casing can fit the outer contour of the underground pipeline to be relocated.

[0010] Optionally, the insertion ratio of the irregularly shaped steel casing is 1:0.

[0011] To achieve the above objectives, according to another aspect of the present invention, a non-circular steel casing for the above-described construction method is provided, comprising at least: a first steel casing assembly and a second steel casing assembly, wherein the first steel casing assembly is connected to the second steel casing assembly, wherein the first steel casing assembly is a single-section arched tongue-and-groove steel casing, and the second steel casing assembly is a single or multiple sections of standard steel casing. Optionally, the arched tongue-and-groove steel casing is formed by rolling steel plates and welding the joints, and then symmetrically cutting off both sides of the bottom of the steel casing into an arched tongue-and-groove shape according to the tongue-and-groove dimensions; and the standard steel casing is formed by rolling steel plates, with the rolled steel plates joined by welding.

[0012] Optionally, the cross-section of the irregular steel casing is circular, the bottom of the irregular steel casing is made into an arched tongue and groove shape, and the arched tongue and groove of the irregular steel casing can fit the outer contour of the underground pipeline to be relocated.

[0013] One embodiment of the above invention has the following advantages or beneficial effects:

[0014] 1. This invention is widely applicable to the relocation and construction of underground pipelines in silty soft soil strata in coastal areas, especially for large-diameter deep-buried underground pipelines.

[0015] 2. Using irregularly shaped steel casings for enclosure allows for the complete excavation of the underground pipeline structure, providing a sufficient and safe cutting and splicing operation surface. This facilitates worker operation, reduces the safety risks of cutting and splicing, and helps improve the quality of pipeline cutting and splicing.

[0016] 3. The factory-prefabricated circular steel structure foundation pit retaining wall has reliable rigidity, strength and stability, and low foundation pit safety risk.

[0017] 4. Compared with traditional underground continuous walls and other enclosures, the construction work area is smaller, the noise of mechanical equipment is lower, the dust is less, and the environmental impact is smaller, which greatly reduces the pollution to the environment and is conducive to civilized construction.

[0018] 5. The use of irregularly shaped steel casings for the relocation of large-diameter, deeply buried underground pipelines can greatly reduce construction costs, accelerate project progress, and ensure successful completion within the specified timeframe.

[0019] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0020] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein:

[0021] Figure 1 This is a construction method for pipeline relocation according to an embodiment of the present invention;

[0022] Figure 2 This is a plan view of the enclosure of the irregularly shaped steel casing according to an embodiment of the present invention;

[0023] Figure 3 This is an elevation view of the enclosure of the irregularly shaped steel casing according to an embodiment of the present invention;

[0024] Figure 4 This is a simplified diagram of the stress calculation for the irregularly shaped steel casing according to an embodiment of the present invention;

[0025] Figure 5 This is a plan view of the underground pipeline routing and boundary positioning hole layout according to an embodiment of the present invention;

[0026] Figure 6 These are the plan and elevation layout diagrams of the MJS foundation reinforcement at the bottom of the pit according to an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the MJS reinforcement method according to an embodiment of the present invention;

[0028] Figure 8 This is a schematic diagram of earthwork excavation inside the irregularly shaped steel casing according to an embodiment of the present invention;

[0029] Figure 9a , Figure 9b as well as Figure 9c According to embodiments of the present invention, the underground pipeline is cut off, the underground pipeline is relocated and welded, and the relocated underground pipeline is routed.

[0030] Figure 10This is a construction schematic diagram of the process of relocating underground pipelines using irregularly shaped steel casings according to an embodiment of the present invention;

[0031] Figure 11 This is a schematic diagram of the completed relocation of underground pipelines using irregularly shaped steel casings according to an embodiment of the present invention;

[0032] Figure 12 These are engineering example illustrations illustrating the pipeline relocation construction method applied in this invention. Detailed Implementation

[0033] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description. Furthermore, the same or similar reference numerals denote the same or similar structures.

[0034] In current technologies, with the rapid development of underground space, the depth of underground engineering construction is also increasing, simultaneously facing the problem of relocating a large number of large-diameter deep-buried pipelines. To safely and reliably relocate and connect large-diameter deep-buried underground pipelines, a special-shaped steel casing structure for underground pipeline relocation construction technology was studied. The relocation technology was analyzed from aspects such as the inner diameter and tongue-and-groove dimensions of the special-shaped steel casing, wall thickness, settlement excitation force, MJS foundation reinforcement at the pit bottom, and the positioning of the underground pipeline's route boundary. The successful relocation of a DN1600 raw water pipe crossing the shield tunnel axis in the Yinzhou Avenue integrated utility tunnel project verified that this technology is applicable to the engineering application of relocating large-diameter deep-buried underground pipelines in silty soft soil areas, and has good economic and social benefits.

[0035] This invention discloses a pipeline relocation construction method. This method, when used for relocating large-diameter, deeply buried underground pipelines, ensures safe, high-quality, and efficient pipeline relocation, and offers significant economic and social benefits, demonstrating unexpected technical advantages. Furthermore, this invention provides a uniquely shaped steel casing, which can be used in the aforementioned pipeline relocation construction method. This uniquely shaped steel casing structure creatively solves the technical problem of pipeline relocation that this invention aims to address, cleverly excavating and exposing the entire underground pipeline, and creatively providing a safe and reliable pipeline cutting and splicing working surface, resulting in unexpected technical advantages.

[0036] The following text will describe in detail the construction method for pipeline relocation and the irregular steel casing of the present invention.

[0037] Figure 1 This is a construction method for pipeline relocation according to an embodiment of the present invention. Figure 2 This is a plan view of the enclosure of the irregularly shaped steel casing according to an embodiment of the present invention. Figure 3 This is an elevation view of the enclosure of an irregularly shaped steel casing according to an embodiment of the present invention. Figure 4 This is a simplified diagram of the stress calculation for the irregularly shaped steel casing according to an embodiment of the present invention.

[0038] according to Figure 1 As shown in the embodiments of the present invention, the pipeline relocation construction method of the present invention includes the following steps: fabricating a corresponding irregular steel casing according to the diameter of the underground pipeline to be relocated, and determining its vibration and sinking parameters; accurately locating the underground pipeline route; sequentially vibrating and sinking the irregular steel casing; reinforcing the foundation at the bottom of the pit according to the MJS reinforcement design scheme; excavating earthwork inside the irregular steel casing; relocating the underground pipeline by cutting and connecting; and removing and recovering the irregular steel casing by cutting and connecting sections from bottom to top.

[0039] More specifically, the process begins with designing the diameter of the irregularly shaped steel casing and the dimensions of the arched tongue-and-groove joint based on the diameter of the underground pipeline to be relocated. The steel casing is then custom-produced in a factory and transported to the construction site in sections. Next, using an XY-1 drilling rig with a plastic drill bit, the actual route of the underground pipeline is accurately determined without damaging it. The surface fill is then removed, and the pipeline's location is marked on the ground. Based on the ground location, the arched tongue-and-groove steel casing is placed and slowly driven 20-30cm into the soil using a PC200 excavator. A vibratory hammer is then used to symmetrically vibrate and sink the casing, sequentially lowering the arched tongue-and-groove steel casing and standard steel casing sections until all sections are submerged. Finally, the site is leveled, and the foundation at the bottom of the pit is reinforced according to the MJS reinforcement design scheme. After the MJS foundation reinforcement cement reached the design age, core sampling of the pile foundation was conducted. Following successful testing, a 40m extended-arm excavator was used to excavate the earth within the confined space of the steel casing until the bottom of the pit was reached. C20 plain concrete was then used to seal the bottom, creating a safe and adequate cutting surface. Cutting personnel entered the casing to carry out the pipeline cutting work, with the relocated pipeline being led upwards along the casing for cutting. Due to the large diameter, length, and weight of the steel casing, it was impossible to use a vibratory hammer for complete extraction and recovery. Therefore, a segmented, bottom-up cutting and sectioning approach was adopted to recover the steel casing, with backfilling occurring simultaneously until complete recovery. At this point, the relocation of the underground deep-buried pipeline using the irregularly shaped steel casing was fully completed.

[0040] according to Figure 2 and Figure 3 As shown, the irregularly shaped steel casing includes at least a first steel casing assembly and a second steel casing assembly. The first steel casing assembly is connected to the second steel casing assembly. The cross-section of the irregularly shaped steel casing is circular (e.g., ...). Figure 2 As shown), and the bottom of the irregularly shaped steel casing is made into an arched tongue-and-groove shape (as shown). Figure 3(As shown). In this embodiment of the invention, the irregularly shaped steel casing is designed with an arched tongue-and-groove shape. By creating an arched tongue-and-groove that fits the dimensions of the underground pipeline, the steel casing can completely fit the underground pipeline, providing a closed structure for the excavation of the foundation pit. This structure resists water and soil from outside the retaining structure, ensuring the completion of the soil within the foundation pit. Traditional retaining structures, such as Larssen sheet piles, steel pipe piles, bored piles, and diaphragm walls, while providing high retaining strength and ensuring the stability of the foundation pit, cannot perfectly fit the underground pipeline to be relocated. During the excavation process, water and soil will flow into the foundation pit through the gap between the retaining structure and the underground pipeline, compromising the safety and reliability of the foundation pit. In other words, the "irregular" feature of the "irregularly shaped steel casing" used in this invention is that the traditional closed structure at the bottom of the steel casing is adjusted to an arched tongue-and-groove structure. The prerequisite for relocating large-diameter underground pipelines is to excavate the entire pipeline. The arched tongue and groove structure of this invention can perfectly fit the outer contour of the underground pipeline to be relocated. As a retaining structure, the excavation of the soil inside the casing can expose the entire pipeline and prevent soil from flowing into the steel casing, providing a closed and safe operating space for pipeline cutting and splicing.

[0041] In this embodiment of the invention, the first steel casing assembly can be a single-section arched tongue-and-groove steel casing, and the second steel casing assembly can be a single or multiple sections of standard steel casing.

[0042] In the method described in this embodiment, a corresponding irregularly shaped steel casing is fabricated based on the diameter of the underground pipeline to be relocated, and its vibration settlement parameters are determined. In other words, the diameter of the irregularly shaped steel casing and the dimensions of the arched tongue and groove are designed based on the diameter of the underground pipeline to be relocated. The steel casing is then custom-produced in a factory and transported to the construction site in sections. The parameters of the irregularly shaped steel casing mainly refer to its material, inner diameter, wall thickness, and tongue and groove dimensions. The vibration settlement parameters mainly refer to the excitation force of the vibratory hammer. The MJS foundation reinforcement parameters mainly refer to the pile diameter, cement content, water-cement ratio, lifting speed, and spraying pressure. Generally, the irregularly shaped steel casing is made of Q235B steel. The inner diameter and tongue and groove dimensions can be determined based on the size of the pipeline to be relocated and the operating space. The wall thickness of the irregularly shaped steel casing and the excitation force of the vibratory hammer are determined by calculation. For MJS foundation reinforcement, the pile diameter is 2400mm with an 800mm overlap; the cement content is 45%; the cement used is 42.5 ordinary Portland cement; the water-cement ratio is 1:1; the lifting speed is 30-40mm / min; and the spraying pressure is controlled according to the soil pressure on site.

[0043] More specifically, such as Figure 2 and Figure 3 As shown, the relevant characteristics of the irregularly shaped steel casing and the tongue and groove dimensions are described. In the embodiments of the present invention... Figure 2In the figure, the inner diameter of the irregular steel casing is D, and d is the diameter of the underground pipeline to be relocated (not shown). The size of the inner diameter D of the irregular steel casing is equal to the sum of the diameter d of the underground pipeline to be relocated and the operating space of 1.5m width on each side, which is the following equation 1.

[0044]

[0045] In Equation 1: —Inner diameter of irregularly shaped steel casing

[0046] One change to the diameter of underground pipeline

[0047] In the embodiments of the present invention Figure 3 In the middle, the special-shaped steel casing has an arched tongue and groove structure, the width of which is the diameter of the underground pipeline to be relocated, and the tongue and groove structure dimensions are Equation 2.

[0048]

[0049]

[0050] In Equation 2: —Width of the arched tongue and groove joint at the top of the irregularly shaped steel casing;

[0051] —Width of the lower opening of the arched tongue and groove joint of the irregularly shaped steel casing;

[0052] One change is to alter the diameter of the underground pipeline;

[0053] An irregularly shaped steel casing with an arched diameter.

[0054] The height of the arched tongue and groove joint of the special-shaped steel casing is: the diameter d of the underground pipeline to be relocated, plus a height of 0.9m (including a bottom sealing layer thickness of 0.3m and a bottom operating space of 0.6m), as shown in Equation 3.

[0055]

[0056] In Equation 3: —Height of the arched tongue and groove joint of the steel casing;

[0057] The diameter of the underground pipeline was changed.

[0058] Next, the wall thickness of the irregular steel casing shall be determined by the soil pressure of the relocated underground pipeline burial depth according to the stiffness requirements, and shall meet the relevant provisions of Article 9.4.1 of GB / T 3650-2020 and Article 5.8.6 of the Technical Specification for Building Pile Foundations (JGJ94-2008). Figure 4This is a simplified diagram of the stress calculation for the irregularly shaped steel casing according to an embodiment of the present invention. First, a strength verification is performed. After the irregularly shaped steel casing has sunk to its final position, the point of maximum stress on the casing is the lateral water and soil pressure at the deepest point. The compressive strength of the steel should be greater than the maximum lateral water and soil pressure (see...). Figure 4 As shown in Equation 4.

[0059]

[0060]

[0061] In Equation 4: —Maximum water and soil pressure

[0062] One-sided earth pressure coefficient (0.5)

[0063] The sinking depth of a steel casing

[0064] Maximum compressive stress of a steel casing

[0065] Safety factor (2.0)

[0066] —Inner diameter and wall thickness of steel casing

[0067] —Design value of compressive strength of steel (205) )

[0068] Secondly, local buckling verification.

[0069] According to Article 5.8.6 of the "Technical Specification for Building Pile Foundations" (JGJ94-2008), as shown in Equation 5, when , ;when , .

[0070] In Equation 5: D, t—inner diameter and wall thickness of the steel casing.

[0071] —Elastic modulus of steel (2.06) ), compressive strength design value (205) )

[0072] Secondly, vibration subsidence verification.

[0073] According to Article 9.4.1 of the Technical Specification for Construction of Highway Bridges and Culverts (JTG / T 3650-2020), when the length of the steel casing is greater than 10m and vibration sinking is required, its diameter-to-thickness ratio (D / t) should not be greater than 120.

[0074] The wall thickness of the steel casing must simultaneously meet the maximum value of the above calculation results.

[0075] Finally, the excitation force of the vibratory hammer

[0076] A shaped steel casing exists statically in the soil. Forced vibration of the casing transmits the vibration to the soil particles in contact with it. This causes relative motion between the soil particles, reducing interparticle friction and lowering the static friction force. Under the action of the vibration, the steel casing sinks. This is illustrated in Equation 6 below.

[0077]

[0078]

[0079]

[0080] In Equation 6: , , —Vibration force, reduced static friction resistance, static friction resistance

[0081] —Extreme value of static friction resistance reduction rate (0.05), static friction resistance reduction rate

[0082] —Soil resistance reduction coefficient (0.52)

[0083] —Weight of the vibration system (weight of steel casing + weight of vibratory hammer + weight of clamp), vibration acceleration

[0084] According to the formula, The relationship was used to calculate the reduction rate of static side friction resistance. This allows us to calculate the minimum excitation force required for the steel casing to vibrate and sink.

[0085] In the above method of this invention embodiment, the route of the underground pipeline to be relocated is accurately located. Figure 5 This is a plan view of the underground pipeline route and boundary positioning hole layout according to an embodiment of the present invention. In other words, an XY-1 drilling rig with a plastic drill bit is used to accurately determine the actual route of the underground pipeline without damaging it, and the surface fill soil is removed to mark the pipeline route on the ground. Specifically, positioning holes are set at equal intervals and symmetrically according to the intersection plane of the arched tongue and groove of the irregular steel casing and the underground pipeline to be relocated, thereby detecting the route of the underground pipeline to be relocated.

[0086] More specifically, in this embodiment of the invention, in order to ensure that the arched tongue and groove joint of the irregular steel casing can accurately "ride" directly above the underground pipeline to be relocated, the specific direction and boundary of the underground pipeline to be relocated must be accurately determined before the irregular steel casing vibrates and sinks.

[0087] Here, we will first discuss the selection of positioning equipment.

[0088] For example, one XY-1 drilling rig can be used for positioning boreholes. A Φ108mm drill bit is used for drilling into the soil. An alloy drill bit is used for drilling up to 2 meters above the underground pipeline to be relocated, while a plastic drill bit is used within 2 meters of the underground pipeline to be relocated, ensuring that the operating underground pipeline is not damaged. A theodolite with a light is used for borehole surveying.

[0089] Regarding "positioning hole positioning," embodiments of the present invention can use pipeline geophysical survey results and pipeline diameter data to lay out the underground pipeline route and boundaries on the ground. Based on the intersection plane of the arched tongue and groove joint of the special-shaped steel casing and the pipeline, the geophysical boundary of the pipeline is laid out on the ground. For example, a positioning hole is set at 15cm intervals, and multiple positioning holes can be set both inside and outside the pipeline boundary, for example, 2-3 positioning holes, to accurately determine the specific boundary of the underground pipeline to be relocated. Figure 5 As shown.

[0090] Regarding the "Drilling and Precise Positioning Results of the Positioning Hole," the following steps should be followed:

[0091] 1) Fix the drilling rig according to the positioning hole position. For example, use a Φ108mm alloy drill bit to open the hole, and drill into the soft soil layer within 2m of the underground pipeline to be relocated. For example, use a Φ108mm plastic drill bit to drill.

[0092] 2) To ensure the verticality of the borehole, the verticality and horizontality of the drill rod should be repeatedly checked during the first 5m of drilling, the position of the drilling rig should be adjusted, and decompression drilling should be adopted.

[0093] 3) When drilling encounters resistance and cannot continue, do not increase drilling pressure or forcefully drill. Instead, compare the results with the pipeline exploration results, check whether the plastic drill bit has reached the pipeline burial depth, and record the borehole plane coordinates and drilling depth.

[0094] 4) When the drilling depth exceeds the burial depth of the pipeline exploration results by 3m or more, drilling should be stopped and the boundary of the underground pipeline corresponding to that location should be determined.

[0095] 5) Based on the drill bit's contact with the underground pipeline to be relocated, determine the specific route and boundary location of the pipeline, with an error margin of 10cm-15cm. Furthermore, analyze and fit the pipeline route and boundary using computer-aided design (CAD) software based on the pipeline diameter; and

[0096] 6) Based on the actual pipeline route and boundary location determined by precise analysis, mark the layout on site.

[0097] In the above method of this invention embodiment, the irregularly shaped steel casing is vibrated and sunk sequentially. In other words, according to the marked ground alignment, an arched tongue-and-groove steel casing is placed, and a PC200 excavator is used to slowly press it into the soil layer, for example, 20cm to 30cm. Then, a vibratory hammer is used to symmetrically vibrate and sunk it, sequentially sinking the arched tongue-and-groove steel casing and the standard section steel casing until all are sunk. In this step, the vibratory sinking equipment is first selected. Two tracked excavators with high-frequency hydraulic vibratory pile drivers are used for the vibratory sinking of the irregularly shaped steel casing. The specifications of the vibratory hammer are selected based on the calculated excitation force of the vibratory hammer, and the excavator specifications are PC-800. The specific vibratory sinking of the irregularly shaped steel casing includes the following steps:

[0098] 1) Clear the miscellaneous fill soil at the relocation site of the underground pipeline to be relocated, level the site for the first section of the sunken steel casing, mark the precise exploration plane position of the underground pipeline boundary, and place the arched tongue and groove of the irregular steel casing in place according to the precisely located underground pipeline boundary.

[0099] 2) Use a PC-200 excavator to evenly press the first arched tongue-and-groove steel casing down to a certain distance in the soil, for example, 20cm-30cm;

[0100] 3) The vibratory hammer of the vibratory pile driver should be symmetrically arranged at two points along the diameter direction of the irregular steel casing, and the vibratory pile driver should be positioned according to the position of the vibratory hammer;

[0101] 4) In the initial stage of sinking of the irregular steel casing, the excitation force of the vibratory hammer is set to 30% of the design value to allow the irregular steel casing to sink slowly. At the same time, the position of the tongue and groove opening plane of the irregular steel casing is measured to ensure that the tongue and groove are in the predetermined position.

[0102] 5) After the tongue and groove joints of the irregular steel casing have completely sunk, increase the excitation force of the vibratory hammer to the design value, maintain a uniform sinking speed, and continuously measure the tilt of the irregular steel casing. During the sinking process, if the tilt deviation is greater than, for example, 10cm, the vibratory pile driver should be stopped to adjust the deviation of the irregular steel casing.

[0103] 6) Each section of the irregularly shaped steel casing can be 2m long. Each section is welded together using CO2 shielded welding with ER304 stainless steel welding wire. The joints of the irregularly shaped steel casing are beveled during factory production, and a retaining steel plate is installed on the preceding section.

[0104] 7) When the tongue and groove joint of the shaped steel casing sinks to the top of the underground pipeline to be relocated, observe the sinking speed of the shaped steel casing. If the sinking speed changes abruptly, vibration sinking should be stopped to prevent the shaped steel casing from damaging the underground pipeline; and

[0105] 8) After the irregular steel casing stops sinking, check whether the depth of the irregular steel casing has reached the burial depth of the pipeline.

[0106] In this method, attention should also be paid to sinking assistance and deviation prevention. For example, 1) to assist the irregular steel casing in sinking smoothly, mechanical hydraulic grease is evenly applied around the irregular steel casing; 2) 10# channel steel is welded along the diameter direction inside the irregular steel casing to form a cross-symmetry, which is cut off as it sinks to prevent the elliptic deformation of the irregular steel casing; 3) the attitude of the irregular steel casing is monitored in real time, and the data is fed back in a timely manner. The position of the vibratory hammer and the magnitude of the excitation force are adjusted according to the monitoring data; and 4) the excitation force of the vibratory hammer is kept stable, and the excitation force is adjusted step by step, without sudden, rapid or fast adjustments.

[0107] In the method described above in this embodiment of the invention, the foundation at the bottom of the pit is reinforced according to the MJS reinforcement design scheme. In this step, the MJS foundation reinforcement parameters mainly refer to the pile diameter, cement content, water-cement ratio, lifting speed, and spraying pressure. For example, the pile diameter for MJS foundation reinforcement is 2400mm with an 800mm overlap; the cement content is 45%; the cement used is 42.5 ordinary Portland cement; the water-cement ratio is 1:1; the lifting speed is 30-40mm / min; and the spraying pressure is controlled according to the on-site soil pressure. Figure 6 These are the plan and elevation layout diagrams of the MJS foundation reinforcement at the bottom of the pit according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the MJS reinforcement method according to an embodiment of the present invention.

[0108] Specifically, the layout of the MJS foundation reinforcement at the bottom of the pit is determined based on the burial depth of the underground pipeline to be relocated, ensuring the stability of the pit bottom against uplift. Generally, the reinforcement depth below the pit bottom inside the irregular steel casing is 3m, and the reinforcement depth around the irregular steel casing outside the pit above the pit bottom is (h+0.5m), where h is the height of the arched tongue and groove joint of the irregular steel casing. The pile diameter is 2400mm, the overlap is 900mm, the cement content is 45%, and PO 42.5 grade ordinary Portland cement is used. See [link to MJS foundation reinforcement layout details] for details. Figure 6 .

[0109] More specifically, the first step is to select the appropriate MJS reinforcement equipment. For example, an MJS-65CVH main unit, an XY-2 pilot hole drilling rig, and a post-grouting support system could be used. Specific reinforcement steps may include pilot hole construction and grout mixing. Pilot hole construction may include the following steps:

[0110] (1) Drilling rig and drill rod parameters. For example, an XY-2 drilling rig equipped with a directional cutting drill bit is used for pre-drilling, and the drilling diameter can be 200 mm;

[0111] (2) During the pre-drilling process, monitor the verticality of the borehole and the stability of the strata at all times, and correct deviations in a timely manner;

[0112] (3) High-quality drilling mud should be used for wall protection during the pre-drilling process. For example, the mud viscosity should be ≥20s, and the specific gravity should be 1.20-1.25.

[0113] (4) Drilling must be carried out in accordance with technical parameters to ensure that the center of the hole is less than 100mm from the center of the pile, the depth is more than 1m greater than the design depth, and the verticality error is less than 1 / 150.

[0114] The shotcrete mixing process may include the following steps:

[0115] (1) The main unit is in place smoothly, all system equipment is connected and debugged to ensure that the MJS grouting equipment is in normal working condition;

[0116] (2) After the pilot hole is completed, slowly lower the MJS drill rod into the hole to the designed depth. If resistance is encountered during lowering, open the cutting water nozzle and use the cylindrical drill bit to drill and lower the rod.

[0117] (3) When lowering and connecting the MJS drill pipe, carefully check the condition of the sealing ring at the interface, clean any debris from the sealing ring promptly, and replace any damaged rings immediately. During the lowering process, pay attention to whether the soil pressure and the pressure monitoring display are consistent;

[0118] (4) The sludge discharge pipe should be tested to ensure it is working properly. First, turn on the reverse suction air pump and reverse suction water pump to check that the sludge discharge is normal. Then turn on the high-pressure cement pump, use 10MPa high-pressure water jet to lift, and open the sludge discharge valve to check that the sludge discharge water is in a normal state.

[0119] (5) MJS lifting rod shotcrete reinforcement: After the borehole is lowered back to the designed depth, high-pressure cement grout is sprayed and lifted upwards at a uniform speed of 40 mm / min. If a sudden change in monitoring pressure is encountered during the spraying process, the grouting pressure should be adjusted in time;

[0120] (6) After raising one section of the drill rod, switch the cement grout to clean water. When the clean water reaches the drill bit position, shut off the back-suction air, back-suction water, and grouting systems to ensure that there is no cement grout residue in the disassembled borehole; and

[0121] (7) The MJS propeller angle of the bottom reinforcement range of the steel casing can be 360°.

[0122] In the above method of this embodiment of the invention, earthwork excavation is carried out inside the irregularly shaped steel casing. Figure 8 This is a schematic diagram of earthwork excavation inside an irregularly shaped steel casing according to an embodiment of the present invention. First, the excavation equipment is selected: due to the small diameter of the steel casing and the deep excavation depth, ordinary excavators cannot excavate to the bottom of the casing. A 40-meter extended-arm PC-800 excavator can be used for earthwork excavation inside the steel casing. The specific earthwork excavation may include the following steps:

[0123] (1) The long-arm excavator selects the mechanical position according to the diameter of the steel casing and the excavation depth to ensure that the bucket can excavate to the bottom of the well;

[0124] (2) Excavate the soil inside the irregular steel casing in layers and blocks. The depth of each layer can be 2-3m. First, excavate the soil in the center of the irregular steel casing, and then excavate the soil on the side of the irregular steel casing.

[0125] (3) Excavated soil shall be directly loaded onto trucks and transported away. It is strictly forbidden to pile soil or materials within 1 meter of the perimeter of the irregular steel casing.

[0126] (4) When the earthwork is excavated to the top of the underground pipeline to be relocated, the bucket of the long-arm excavator is replaced with a narrow small bucket of 0.6m (length) * 0.5m (width) * 0.5m (height), and the excavator position is adjusted to be consistent with the direction of the underground pipeline to be relocated, so as to ensure that the soil between the underground pipeline to be relocated and the special-shaped steel casing can be excavated smoothly.

[0127] (5) If the soil directly beneath the underground pipeline to be relocated cannot be excavated using a long-arm excavator, after the soil between the underground pipeline and the irregular steel casing has been excavated, the soil directly beneath the pipeline should be manually removed and piled in the gap, and then transported to the surface using a long-arm excavator; and

[0128] (6) After the earthwork is excavated to the bottom of the underground pipeline, for example, 0.9m, the excavation is stopped, the elevation is checked, and C35 plain concrete is poured to seal the bottom. The thickness of the seal can be, for example, 0.3m.

[0129] like Figure 8 As shown, the excavator can excavate to the bottom and remove the soil between the underground pipeline to be relocated and the special-shaped steel casing, thereby excavating and exposing the entire underground pipeline to be relocated, thus providing a safe and reliable pipeline cutting and splicing working face.

[0130] In the above method of this invention embodiment, the underground pipeline to be relocated is cut and relocated. Figure 9a , Figure 9b as well as Figure 9c This invention relates to the removal, relocation, and welding of underground pipelines, as well as the relocated pipeline route, according to embodiments of the present invention. Specifically, after the excavation and sealing of the earthwork within the irregularly shaped steel casing are completed, the cutting and relocation work of the underground pipeline to be relocated is carried out. For example, the following points should be noted in the steps of this method:

[0131] 1. Before the relocation and cutting of the pipeline, the relevant shutdown procedures must be completed in advance with the property owner's consent. The cutting operation can only be carried out after the residual medium in the pipeline has been drained.

[0132] 2. Generally, large-diameter pipes to be relocated are made of steel. Cutting is done using oxy-acetylene welding, and welding uses carbon dioxide shielded welding, electric arc welding, etc. For other pipe materials, cutting and welding equipment will be selected based on the material of the pipe.

[0133] 3. Before welding the underground pipeline to be relocated, use oxy-acetylene welding to bevel the pipe opening. After beveling, use an angle grinder to clean the weld slag and other debris at the pipe opening to ensure the metallic luster of the bevel.

[0134] 4. When welding pipes, use hoisting positioning welding. Weld one point at the top and bottom of the pipe, and one point on the side, for a total of 4 points.

[0135] 5. During the welding process, the shape and size of the molten pool remain basically consistent, the molten iron in the pool is clear and bright, and the molten hole penetrates into the base material on each side by 0.5mm-1mm.

[0136] Furthermore, in the aforementioned pit bottom foundation reinforcement and underground pipeline relocation steps, after the MJS foundation reinforcement cement reaches the design age, core sampling of the pile foundation is conducted. Once the test is passed, a 40m extended-arm excavator is used to excavate the earthwork within the confined space of the steel casing until the bottom of the pit is reached. C20 plain concrete is then used to seal the bottom, creating a safe and adequate cutting work surface. Cutting personnel enter the casing to carry out the pipeline cutting work, with the relocated pipeline being led upwards along the casing for the cutting. In other words, after the pile foundation core sampling is passed, earthwork is excavated within the confined space of the irregularly shaped steel casing until the bottom of the pit is reached, followed by sealing the bottom to create a safe and adequate cutting work space. The arched tongue and groove joint of the arched steel casing can fit snugly against the outer contour of the underground pipeline to be relocated.

[0137] Furthermore, in this embodiment of the invention, the insertion ratio of the irregularly shaped steel casing is 1:0. The insertion ratio refers to the ratio of the length of the vertical retaining structure above the bottom of the pit to the length below the bottom of the pit. This insertion ratio serves as a safety reserve factor to counteract soil inflow at the bottom of the pit. Traditional retaining structures typically have an insertion ratio of 1:1. The irregularly shaped steel casing, as a retaining structure for pit excavation, creatively improves the insertion ratio to 1:0, requiring almost no safety reserve. To address the soil inflow problem, the pit bottom is reinforced with MJS, fully utilizing the excellent soil strength effect after MJS reinforcement, ensuring sufficient strength of the soil at the pit bottom to resist soil inflow. Calculations show that the reinforcement range and depth in this invention sufficiently meet the requirements (see above).

[0138] In other words, an insertion ratio of 1:0 means almost no safety margin. This 1:0 ratio is unique to foundation pit excavation in coastal soft soil areas and is being used for the first time. Other traditional foundation pit retaining structures use a certain insertion ratio as a safety margin against lateral displacement. This ratio setting is an innovative first-time application. Compared to the traditional 1:1 ratio, a 1:0 insertion ratio saves on retaining structure materials and reduces costs. Secondly, the retaining structure does not need to be inserted too deeply, reducing the difficulty of driving it in, avoiding uncertainties, and facilitating rapid on-site relocation. Furthermore, the shallower driving depth reduces disturbance to deeper soil layers, lowering the risk of foundation pit deformation and providing unexpected technical benefits. Moreover, the 1:0 insertion ratio retaining structure can provide a new approach for the construction of structures such as stormwater and sewage wells in municipal engineering, expanding its application scope and scenarios.

[0139] In the above-described method of this invention embodiment, the irregularly shaped steel casing is removed and recovered by cutting and splicing sections from bottom to top. This is because the irregularly shaped steel casing has a large diameter, long length, and heavy weight, making it impossible to pull it out and recover it as a whole using a vibratory hammer. Therefore, the irregularly shaped steel casing is recovered by cutting and splicing sections from bottom to top, with backfilling occurring as the sections are cut, until the entire casing is recovered. Specifically, for example, the outer bottom of the irregularly shaped steel casing is reinforced by MJS for 3 meters, and the inner bottom of the irregularly shaped steel casing is sealed with C35 plain concrete for 0.5 meters. Due to the consolidation of the concrete and the weight of the irregularly shaped steel casing, it cannot be pulled out as a whole. The steel casing is recovered using a "bottom-up, section-by-section cutting, layer-by-layer backfilling" method, with the recovery range being the height from the top of the relocated underground pipeline to the ground level. Furthermore, the section cutting dimensions of the irregularly shaped steel casing are 0.5m (length) * 0.4m (width). Before cutting, a talcum powder pen is used to mark the inner wall of the irregularly shaped steel casing according to the cutting dimensions using a grid pattern. In addition, oxy-acetylene welding is used to cut off the irregularly shaped steel casing. After each section is cut off, soil is backfilled along the side wall inside the irregularly shaped steel casing up to the outer wall of the relocated underground pipeline, and the soil is compacted. After one layer (e.g., 0.5m) of the irregularly shaped steel casing is cut off, the backfilled soil is compacted again.

[0140] With this, the relocation of underground deep-buried pipelines using irregularly shaped steel casings has been completed.

[0141] To better understand this invention, it will be based on Figure 10 and Figure 11 This invention provides a general overview of the process of relocating underground pipelines using irregularly shaped steel casings, as described in this embodiment. Figure 10 This is a construction schematic diagram of the process of relocating underground pipelines using irregularly shaped steel casings according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the completed relocation of underground pipelines using irregularly shaped steel casings according to an embodiment of the present invention.

[0142] The external structure of the irregular-shaped steel casing is formed by sequentially sinking and welding one or more standard steel casings and one arched tongue-and-groove steel casing. The irregular-shaped steel casing has a circular cross-section, and its bottom is made into an arched tongue-and-groove shape, which fits snugly against the outer contour of the underground pipeline to be relocated. The arched steel casing is sunk to the depth of the underground pipeline to be relocated, the soil at the bottom and above the casing is reinforced, and the soil inside the casing is excavated, using the casing wall as a retaining wall to resist water and soil pressure. After the excavation and sealing of the pit are completed, a reliable working surface is provided for the safe, high-quality, and efficient cutting and splicing of the underground pipeline.

[0143] After the irregularly shaped steel casing is lowered to the design elevation, there is a gap at the junction of the arched tongue-and-groove steel casing and the underground pipeline, preventing a seamless fit. This area is prone to soil inrush. The MJS foundation reinforcement method is used to reinforce the soil at this location, ensuring the surrounding soil is compacted and preventing water and soil from flowing into the steel casing, thus avoiding safety accidents. In this way, the arched tongue-and-groove structure of the present invention can perfectly fit the outer contour of the underground pipeline to be relocated. Excavating the soil inside the casing as a retaining structure exposes the entire pipeline and prevents soil from flowing into the steel casing. This provides a closed and safe operating space for pipeline cutting and splicing, resisting water and soil from outside the retaining structure. It ensures that the soil in the foundation pit can be completely excavated to expose the underground pipeline and provides a safe and reliable space for pipeline cutting and splicing, thereby solving the technical problem to be addressed by the present invention and bringing unexpected technical effects.

[0144] Due to the small diameter of the irregularly shaped steel casing and the deep excavation depth, traditional excavation equipment faces difficulties and low construction efficiency. To address this issue, we adopted a 40-meter extended-arm excavator for excavation. Compared to traditional equipment, the extended-arm excavator improved construction efficiency and safety. The soil at the bottom of the underground pipeline was excavated manually, solving the problem of inaccessibility by mechanical equipment and preventing damage to the pipeline and over-excavation by mechanical equipment.

[0145] In short, underground pipelines are cut, relocated, and welded inside irregularly shaped steel casings. Figure 10 The underground pipeline's route has changed, and the underground pipeline has been successfully relocated (e.g.) Figure 11 (As shown).

[0146] This invention is suitable for the relocation of underground pipelines in silty soft soil strata in coastal areas, especially for large-diameter, deeply buried underground pipelines. Compared with traditional retaining methods that cannot relocate underground pipelines, this method offers significant advantages such as low construction risk, high safety, low cost, and short construction period. Moreover, engineering practice has proven that, compared with adjusting the route or burial depth of the project, the use of irregularly shaped steel casing retaining structures for relocating conflicting large-diameter, deeply buried underground pipelines offers the following advantages in terms of construction period, economic benefits, and social benefits:

[0147] 1. Compared to not relocating conflicting pipelines, relocating them can be achieved by adjusting the route or burial depth of the proposed project. However, adjusting the route involves policy reviews and approvals from multiple departments, including planning, land use, and environmental impact assessment, significantly increasing the construction time. Using specially shaped steel casings to enclose conflicting large-diameter, deeply buried underground pipelines greatly shortens the construction time.

[0148] 2. Economic and social benefits

[0149] By relocating the conflicting large-diameter, deeply buried underground pipelines, the increased engineering costs caused by adjustments to the route and burial depth of the planned project were avoided. At the same time, the impact of project changes on the social environment was reduced, resulting in good economic and social benefits.

[0150] Next, this invention will further illustrate the creative improvement of its construction method by using a pipeline relocation construction method from a certain project. Using the method of this invention, a DN1600 large-diameter raw water pipe in a certain city was successfully relocated, ensuring that the normal water supply for citizens was not affected, while also guaranteeing the normal advancement of the tunnel boring machine, without impacting the overall investment, schedule, or progress of the project. Figure 12 These are engineering example illustrations illustrating the pipeline relocation construction method applied in this invention.

[0151] In this engineering example, the strata traversed are mainly ②2 layers of silty clay, ③1 layer of silt, ③2 layers of silty clay, ④1 layer of silty clay, ④2 layers of clay, and ⑤1 layer of clay.

[0152] The relocation of a DN1600 raw water pipe, which crosses the tunnel boring machine (TBM) axis, involves the use of a special-shaped steel casing. The pipe has a diameter of 1600mm, a wall thickness of 18mm, and is made of steel. This pipe is one of the main raw water supply pipelines in the city. The conflict location is approximately 135m south of the No. 10 starting shaft. The bottom elevation of the raw water pipe is -7.24m, the top elevation of the TBM is -7.04m, and the conflict range between the TBM and the raw water pipe is 20cm. Technical parameters for the relocation of the special-shaped steel casing:

[0153] 1. The inner diameter of the steel casing is D = 4.6m;

[0154] 2. Steel casing tongue and groove dimensions: b_1=2.0m; b_2=2.4m;

[0155] 3. Steel casing wall thickness: t=40mm;

[0156] 4. Vibratory hammer excitation force requirement: P_0 ≥ 689.43kN;

[0157] 5. MJS reinforcement parameters: pile diameter 2400mm, overlap 900mm, cement content 45%, cement is PO 42.5 grade ordinary Portland cement.

[0158] 6. MJS reinforcement range: 3m above and below the bottom of the pit.

[0159] like Figure 12 As shown, normal water supply was restored after the underground pipeline relocation was completed. The method of this invention has economic and social benefits, as well as unexpected technical effects. First, regarding the economic benefits:

[0160] The application of the special-shaped steel casing enclosure construction technology for the relocation of large-diameter deep-buried underground pipelines in this project successfully relocated the DN1600 large-diameter raw water pipe, avoiding the increase in project costs caused by adjustments to the project route and burial depth. It did not affect the overall investment, construction period, or progress of the project. Compared with the tens of millions of yuan increase in investment for the relocation of the project route, the relocation of the raw water pipe only cost a few hundred thousand yuan and greatly shortened the construction period. The city's pipeline "clearance" campaign is progressing steadily.

[0161] Secondly, regarding the social impact:

[0162] This section of the DN1600 large-diameter raw water pipe is one of the main water supply pipelines in the city's main urban area. It only took 5 days from the removal of the raw water pipe to the completion of the relocation and restoration of normal water supply, ensuring that the normal water use of residents in the main urban area was not affected and avoiding adverse negative impacts caused by water problems for residents.

[0163] Next, this invention will describe the irregularly shaped steel casing used in the pipeline relocation construction method described above. In an embodiment of this invention, the irregularly shaped steel casing includes at least: a first steel casing assembly and a second steel casing assembly, the first steel casing assembly being connected to the second steel casing assembly, wherein the first steel casing assembly is a single-section arched tongue-and-groove steel casing, and the second steel casing assembly is a single or multiple sections of standard steel casing. Specifically, as described above... Figure 2 and Figure 3 As shown, where Figure 2 This is a plan view of the enclosure of the irregularly shaped steel casing according to an embodiment of the present invention. Figure 3 This is an elevation view of the enclosure of an irregularly shaped steel casing according to an embodiment of the present invention.

[0164] In this embodiment of the invention, the arched tongue-and-groove steel casing is formed by rolling steel plates into a circle and welding the joints. Then, according to the tongue-and-groove dimensions, the bottom two sides of the irregularly shaped steel casing are symmetrically cut into an arched tongue-and-groove shape. The standard steel casing is formed by rolling steel plates into a circle, and the rolled steel plates are connected by welding the joints. In this embodiment of the invention, the insertion ratio of the irregularly shaped steel casing is 1:0. 6. The irregularly shaped steel casing according to claim 1, characterized in that the inner diameter of the irregularly shaped steel casing is larger than the diameter of the underground pipeline to be relocated. According to the present invention... Figure 2 and Figure 3 In this embodiment of the invention, the arched tongue and groove height h of the irregularly shaped steel casing is greater than the diameter (not shown) of the underground pipeline to be relocated; the inner diameter D of the irregularly shaped steel casing is greater than the diameter of the underground pipeline to be relocated; the arched tongue and groove of the irregularly shaped steel casing includes the upper width of the arched tongue and groove. and the width of the bottom of the arched tongue and groove The width of the arched tongue and groove top opening Smaller than the bottom width of the arched tongue and groove The arched diameter of the irregularly shaped steel casing Equal to the width of the arched tongue and groove top of the irregular steel casing .

[0165] like Figure 2 As shown, the cross-section of the irregularly shaped steel casing is circular, and as... Figure 3 As shown, the bottom of the irregularly shaped steel casing is made into an arched tongue and groove that fits the dimensions of the underground pipeline to be relocated, thus allowing the irregularly shaped steel casing to fit completely into the underground pipeline. In other words, the cross-section of the irregularly shaped steel casing is circular, the bottom of the irregularly shaped steel casing is made into an arched tongue and groove shape, and the arched tongue and groove of the irregularly shaped steel casing can fit the outer contour of the underground pipeline to be relocated. In this invention, the cross-section of the irregularly shaped steel casing is circular, and the irregular shape refers to the arched tongue and groove form of the bottom of the steel casing, creatively improving upon the traditional steel casing (which is a flat-mouth form).

[0166] In other words, the "irregular" feature of the "irregularly shaped steel casing" in this invention embodiment is that the traditional closed structure at the bottom of the steel casing is adjusted to an arched tongue-and-groove structure. Since the relocation of deep-buried large-diameter pipelines requires the complete excavation of the underground pipeline to be relocated, the arched tongue-and-groove structure of this invention can perfectly fit the outer contour of the underground pipeline to be relocated. As a retaining structure, excavating the soil inside the casing can completely expose the underground pipeline to be relocated and prevent soil from flowing into the steel casing, providing a closed and safe operating space for the cutting and splicing of the pipeline to be relocated.

[0167] More specifically, large-diameter underground pipelines are often buried at great depths, and relocation requires excavating and excavating to expose the pipeline. This raises the question of how to conduct safe and reliable excavation. In coastal areas with soft soil, foundation pit excavation is a particularly dangerous sub-project, involving multiple major risk sources. Inadequate retaining structures can lead to significant foundation pit deformation, or even collapse. Traditional retaining structures, such as Larssen sheet piles, steel pipe piles, bored piles, and diaphragm walls, while providing high strength and ensuring foundation pit stability, cannot perfectly fit the underground pipeline to be relocated. During excavation, water and soil can seep into the foundation pit through gaps in the seal between the retaining structure and the underground pipeline, compromising the safety and reliability of the foundation pit. The "irregularly shaped steel casing" of the present invention, by making an arched tongue and groove that fits the size of the underground pipeline to be relocated, can completely fit the underground pipeline to be relocated, providing a closed structure for the excavation of the foundation pit, which is used to resist the water and soil outside the retaining structure, ensuring that the soil in the foundation pit can be completely excavated to expose the underground pipeline, and providing a safe and reliable space for the cutting and splicing of the underground pipeline to be relocated. Thus, it creatively overcomes the technical difficulties in the prior art and brings unexpected technical effects. For specific technical effects, please refer to the technical effects mentioned in the above method.

[0168] Furthermore, the technical features of the irregularly shaped steel casing described in the pipeline relocation construction method are naturally included in the description of the installation of the irregularly shaped steel casing. In other words, the irregularly shaped steel casing includes the technical features of the installation involved in the description of the aforementioned pipeline relocation construction method.

[0169] Engineering practice has proven that, compared with adjusting the route or burial depth of the project to be constructed, the use of irregularly shaped steel casings for the protection of large-diameter, deeply buried underground pipelines in conflict situations has significant advantages in terms of construction period, economic and social benefits, and has unexpected technical effects.

[0170] Compared to not relocating conflicting pipelines, relocating them by adjusting the route or burial depth of the proposed project can significantly increase construction time. Adjusting the route involves policy reviews and approvals from multiple departments, including planning, land use, and environmental impact assessments. Using specially shaped steel casings to enclose conflicting large-diameter, deeply buried underground pipelines greatly shortens the construction time. Furthermore, it avoids increased engineering costs caused by adjusting the route and burial depth of the proposed project, while also reducing the social and environmental impact of project changes, resulting in good economic and social benefits.

[0171] Compared to traditional retaining methods such as Larssen steel plates, PC steel pipe piles, and diaphragm walls, shaped steel casing retaining systems can fit snugly against large-diameter, deeply buried underground pipelines, completely excavating and exposing the underground pipeline, providing a safe and reliable cutting and splicing space for pipeline relocation. Shaped steel casing retaining systems are custom-made in the factory, resulting in high structural strength and safe, convenient, and efficient construction. In terms of civilized construction, shaped steel casing retaining systems offer advantages such as a smaller construction work area, lower noise from machinery, and less dust generation.

[0172] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A construction method for pipeline relocation, comprising: According to the diameter of the underground pipeline to be relocated, a corresponding irregular steel casing is made, and its vibration settlement parameters are determined. Accurately locate the route of underground pipelines to be relocated; The irregularly shaped steel casing was vibrated and lowered sequentially. Based on the MJS reinforcement design scheme, the foundation at the bottom of the pit was reinforced. Earthwork excavation was carried out inside the irregularly shaped steel casing; Carry out the relocation and connection of underground pipelines to be relocated; as well as The irregularly shaped steel casing is removed and recycled by cutting and splicing sections from bottom to top. The irregularly shaped steel casing includes at least a first steel casing assembly and a second steel casing assembly. The first steel casing assembly is connected to the second steel casing assembly. The cross-section of the irregularly shaped steel casing is circular, and the bottom of the irregularly shaped steel casing is made into an arched tongue and groove shape.

2. The construction method according to claim 1, further comprising: Based on the intersection plane position of the arched tongue and groove of the irregular steel casing and the underground pipeline to be relocated, positioning holes are set at equal intervals and symmetrically to detect the direction of the underground pipeline to be relocated.

3. The construction method according to claim 1, characterized in that, The first steel casing assembly is a single-section arched tongue-and-groove steel casing, and the second steel casing assembly is a single or multiple sections of standard steel casing.

4. The construction method according to claim 3, further comprising: According to the marked direction and position, place the arched tongue and groove steel casing, and sink the arched tongue and groove steel casing and the standard section steel casing in sequence until they are all sunk.

5. The construction method according to claim 1, further comprising: After the core sampling of the pile foundation is deemed qualified, the earthwork is excavated in the narrow space of the irregularly shaped steel casing until the bottom of the pit is reached. Then the bottom is sealed to create a safe and full-scale cutting and splicing working space.

6. The construction method according to claim 3, further comprising: The arched tongue and groove joint of the arched steel casing can fit the outer contour of the underground pipeline to be relocated.

7. The construction method according to claim 1, characterized in that: The insertion ratio of the irregularly shaped steel casing is 1:

0.

8. A shaped steel casing for use in the construction method of claims 1-7, comprising at least: A first steel casing assembly and a second steel casing assembly are connected together. The first steel casing assembly is a single-section arched tongue-and-groove steel casing, and the second steel casing assembly is a single or multiple sections of standard steel casing.

9. The irregularly shaped steel casing according to claim 1, characterized in that, The arched tongue-and-groove steel casing is formed by rolling steel plates and welding the joints. The bottom sides of the irregular steel casing are symmetrically cut into an arched tongue-and-groove shape according to the tongue-and-groove dimensions. The standard steel casing is formed by rolling steel plates and welding the rolled steel plates together.

10. The irregularly shaped steel casing according to claim 1, characterized in that, The cross-section of the irregularly shaped steel casing is circular, and the bottom of the irregularly shaped steel casing is made into an arched tongue and groove shape, and the arched tongue and groove of the irregularly shaped steel casing can fit the outer contour of the underground pipeline to be relocated.

Images