Pipe jacking engineering liquid nitrogen freezing hole secondary opening sealing construction device

Abstract

The utility model provides a kind of top pipe engineering liquid nitrogen frozen hole secondary opening sealing construction device including orifice pipe, gate valve, sealing device, drill rod and liquid nitrogen delivery pipe;Orifice pipe, gate valve and sealing device are sequentially communicated and are set, and the three can be communicated to form passage, drill rod is matched with passage and is set, and it can be extended to drilling position by passage and drilled, liquid nitrogen delivery pipe can be matched in sealing device, and cooperate with liquid nitrogen delivery into passage, until delivery into drilling;Orifice pipe and gate valve connection gap use hemp silk to seal;Sealing device and drill rod connection gap use hemp silk to seal.The device structure design is reasonable, and each component is clear in division of labour, and link closely, orifice pipe component realizes orifice positioning and preliminary sealing, sealing component provides main sealing force and pressure monitoring adjustment function, pipeline component satisfies drilling and liquid nitrogen delivery demand, reduces construction difficulty and improves construction efficiency.

Description

Technical Field

[0001] This utility model relates to the field of pipe jacking construction technology, and more specifically, to a secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking projects. Background Technology

[0002] When pipe jacking traverses complex strata (such as water-rich soft soil layers, sand layers, etc.), liquid nitrogen freezing is often used for stratum pre-reinforcement. By injecting liquid nitrogen into the freezing hole, the surrounding soil freezes to form a curtain, which serves to reinforce the soil and prevent water seepage. However, in secondary drilling operations, it is necessary to drill holes again in the already constructed working well wall and other structures to achieve reliable sealing. Existing sealing devices have problems such as poor sealing effect, unreasonable structural design, and difficulty in adapting to the low temperature and high pressure environment of liquid nitrogen. This can easily lead to liquid nitrogen leakage and formation water seepage, affecting the freezing reinforcement effect and even causing safety accidents during pipe jacking construction. Therefore, there is an urgent need for a sealing construction device specifically designed for secondary drilling of liquid nitrogen freezing holes in pipe jacking projects. Summary of the Invention

[0003] In view of this, the present invention proposes a secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering, comprising: a borehole pipe, a gate valve, a sealing device, a drill rod, and a liquid nitrogen delivery pipe; the borehole pipe, the gate valve, and the sealing device are sequentially connected and can form a passage; the drill rod is matched with the passage and can extend through the passage to the drilling position for drilling; the liquid nitrogen delivery pipe is matched and installed in the sealing device and cooperates to deliver liquid nitrogen into the passage until it is delivered into the drilling hole.

[0004] Preferably, the free end of the orifice pipe is provided with a positioning element, which can position the orifice pipe and confirm its installation position on the well wall.

[0005] Preferably, the positioning element is a rebar positioning element.

[0006] Preferably, an annular steel plate is fitted onto the orifice pipe, and the annular steel plate is located on the outer side of the well wall of the orifice pipe. The annular steel plate is connected to the fixing structure on the side of the well wall by bolts, so that the annular steel plate is tightly attached to the well wall, which plays a role in initially fixing the position of the orifice pipe.

[0007] Preferably, the bypass pipeline of the gate valve is further provided with a bypass gate valve, which can be used to monitor pressure changes in the orifice.

[0008] Preferably, the gap between the orifice pipe and the gate valve is sealed with hemp fiber.

[0009] Preferably, hemp fibers are used to seal the gap between the sealing device and the drill rod.

[0010] Preferably, the liquid nitrogen delivery pipe is a stainless steel pipe.

[0011] Preferably, the liquid nitrogen delivery pipe is also equipped with a liquid supply pipe, which connects the liquid nitrogen delivery pipe and the liquid nitrogen supply system, and can deliver the liquid nitrogen to the location to be frozen.

[0012] This utility model provides a secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking projects, which has the following advantages: With superior sealing performance, a multi-layer sealing structure is constructed through the synergistic effect of the orifice pipe, annular steel plate, sealing device and hemp fiber. The annular steel plate blocks the leakage channels inside and outside the well wall, and the sealing device and hemp fiber fill the connection gaps, effectively preventing liquid nitrogen leakage and formation water infiltration. Actual engineering verification shows that the sealing leakage rate is much lower than that of traditional devices, ensuring the effect of liquid nitrogen freezing and consolidating the formation and improving the safety of pipe jacking construction. The structure is rationally designed, with clear division of labor and tight connection among the components. The orifice pipe assembly realizes orifice positioning and initial sealing, the sealing assembly provides the main sealing force and pressure monitoring and adjustment functions, and the pipeline assembly meets the needs of drilling and liquid nitrogen transportation. This design makes the construction process clear, reduces the construction difficulty, improves the construction efficiency, and facilitates operation and maintenance by construction personnel. With strong environmental adaptability, this device can adapt to the requirements of different well wall thicknesses and formation conditions in pipe jacking projects. It can meet diverse construction needs by adjusting parameters such as the length of the orifice pipe and the amount of sealing material filling. At the same time, the stainless steel pipe, sealing device and other components have low temperature resistance and corrosion resistance, and can work stably for a long time in the harsh environment of liquid nitrogen freezing construction. Attached Figure Description

[0013] Various other advantages and benefits will become apparent 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. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the drilling process of the secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering provided in this embodiment of the utility model; Figure 2 A schematic diagram of the pipe-laying process of the secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering provided in this embodiment of the utility model; 1. Orifice pipe, 2. Gate valve, 3. Sealing device, 4. Drill pipe, 5. Liquid nitrogen delivery pipe (stainless steel pipe), 6. Positioning component, 7. Annular steel plate, 8. Bypass gate valve, 9. Hemp fiber, 10. Liquid supply pipe, 11. Well wall. Detailed Implementation

[0014] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0015] See Figure 1-2 As shown in the figure, this is a secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering provided by an embodiment of the present invention. It includes: a borehole pipe 1, a gate valve 2, a sealing device 3, a drill rod 4, and a liquid nitrogen delivery pipe 5. The borehole pipe 1, the gate valve 2, and the sealing device 3 are sequentially connected and can form a passage. The drill rod 4 is matched with the passage and can extend through the passage to the drilling position for drilling. The liquid nitrogen delivery pipe 5 can be matched and installed in the sealing device 3 and cooperates to deliver liquid nitrogen into the passage until it is delivered into the drilling hole.

[0016] Reference Figure 1 As shown, the free end of the orifice pipe 1 is provided with a positioning element 6, which can position the orifice pipe 1 and confirm its installation position on the well wall 11. Preferably, the positioning element is a steel bar positioning element.

[0017] Reference Figure 1-2 As shown, an annular steel plate 7 is fitted onto the orifice pipe 1. The annular steel plate 7 is located on the outer side of the well wall of the orifice pipe 1. The annular steel plate 7 is connected to the fixing structure on the side of the well wall by bolts, so that the annular steel plate 7 is tightly attached to the well wall, which plays the role of initially fixing the position of the orifice pipe 1.

[0018] Continue to refer to Figure 1-2 As shown, a bypass gate valve 8 is also provided on the bypass pipeline of the gate valve 2, which can be used to monitor pressure changes in the orifice.

[0019] Reference Figure 1-2 As shown, the gap between the orifice pipe 1 and the gate valve 2 is sealed with hemp fibers 9. The gap between the sealing device 3 and the drill rod 4 is also sealed with hemp fibers 9.

[0020] Reference Figure 2 As shown, the liquid nitrogen delivery pipe 5 is a stainless steel pipe.

[0021] Continue to refer to Figure 2As shown, the liquid nitrogen delivery pipe 5 is also equipped with a liquid supply pipe 10, which connects the liquid nitrogen delivery pipe 5 and the liquid nitrogen supply system, and can deliver the liquid nitrogen to the position to be frozen.

[0022] The following provides a detailed explanation of the function of each component in a secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering: I. Device Structure (a) Orifice tube assembly 1) The orifice pipe 1 serves as the connection channel between the freezing hole and the well wall. Its length is adapted to the thickness of the well wall, and it is generally designed to be 500-1000mm. The material is selected as a high-strength and well-sealing pipe (such as seamless steel pipe), which can withstand the soil pressure on the side of the well wall and the force of subsequent construction, providing an installation foundation for the subsequent sealing structure, and guiding the installation direction of the drill rod 4 and the stainless steel pipe 5.

[0023] 2) An annular steel plate 7 is fitted onto the portion of the orifice pipe 1 located on the outer side of the well wall. It has a central hole matching the outer diameter of the orifice pipe 1 and bolt holes along its edges. The annular steel plate 7 is connected to a fixing structure on the side of the well wall (such as a pre-embedded steel plate or anchors within the well wall) via bolts, ensuring the annular steel plate 7 is tightly fitted against the well wall. This serves two purposes: firstly, it initially fixes the position of the orifice pipe, limiting its displacement during construction; secondly, the tight fit between the annular steel plate 7 and the well wall blocks leakage channels along the orifice pipe inside and outside the well wall, thus improving the sealing performance of the orifice.

[0024] 3) Rebar positioning component 6 is used to determine the installation position of the orifice pipe 1 on the well wall, avoiding conflict between the orifice pipe 1 and the reinforcing bars inside the well wall during installation. A rebar scanner can be used in conjunction with marking components (such as positioning rebars or marking blocks) to mark the accurate installation point of the orifice pipe 1 on the well wall surface, ensuring that the installation position of the orifice pipe 1 meets the design requirements, laying the foundation for subsequent drilling and pipe laying operations.

[0025] (ii) Sealing assembly 1) Gate valve 2, installed at the end of orifice pipe 1, is used to control the connection between the freezing hole and the outside. During drilling, gate valve 2 can be closed to prevent large amounts of slag and water from flowing out of the well wall; during the liquid nitrogen transportation stage, it can precisely control the supply and stop of liquid nitrogen, and also facilitates the testing and maintenance of sealing performance.

[0026] 2) Bypass gate valve 8, used in conjunction with gate valve 2, is installed on the bypass pipeline of gate valve 2. During drilling operations, the pressure changes inside the borehole can be monitored through the bypass gate valve 8 to understand the construction situation inside the borehole in real time; in the sealing test stage, it can realize the bypass circulation of the test medium (such as compressed air, water), which is convenient for testing the sealing effect of the sealing device; during liquid nitrogen transportation, it can also be used to regulate the pressure inside the borehole to ensure construction safety.

[0027] 3) Sealing device 3 is a rigid sealing structure, installed in conjunction with orifice pipes, gate valves, etc. It has an internal sealing chamber that can be filled with sealing material (such as hemp fiber). The sealing material is compacted using mechanical structures (such as glands and bolts) to form a reliable sealing surface. The sealing device can adapt to the low-temperature, high-pressure environment of liquid nitrogen, effectively preventing liquid nitrogen leakage and formation water infiltration. During drilling and pipe laying, it works with drill pipes and stainless steel pipes respectively to meet the sealing requirements at different construction stages.

[0028] 4) Hemp fiber 9, used as a flexible sealing material, is filled in the joints between orifice pipes and gate valves, sealing devices and drill rods (or stainless steel pipes), etc. Hemp fiber has good flexibility and plasticity, capable of filling tiny gaps. Under the mechanical pressure of the sealing device, it tightly adheres to the connection, enhancing the sealing effect. Before use, the hemp fiber can be soaked in oil or otherwise treated for waterproofing to further improve its sealing performance and impermeability.

[0029] (iii) Piping assemblies 1) Drill rod 4 is used during drilling to break up the soil in the well wall and strata, forming a channel for the freezing hole. The diameter and length of the drill rod are adapted to the drilling requirements, and it has sufficient strength and wear resistance to ensure smooth drilling under the drive of the drilling rig, providing a channel for the subsequent installation of stainless steel pipes.

[0030] 2) Stainless steel pipe 5, as the main pipeline for liquid nitrogen transportation, possesses the characteristics of low temperature resistance and corrosion resistance, and can adapt to the environmental requirements of liquid nitrogen freezing construction. After drilling is completed, stainless steel pipe 5 replaces the drill rod and is lowered into the freezing hole. One end of it is connected to the liquid supply pipe to transport liquid nitrogen to the freezing area of ​​the formation; the other end is used in conjunction with the sealing device, which is sealed by filling with hemp fiber to ensure the airtightness during the liquid nitrogen transportation process.

[0031] 3) Liquid supply pipe 10 connects stainless steel pipe 5 to the liquid nitrogen supply system. It uses low-temperature and high-pressure resistant pipe materials (such as low-temperature resistant rubber pipes or stainless steel corrugated pipes) to ensure smooth liquid nitrogen delivery. The connection between liquid supply pipe 10 and stainless steel pipe 5 must be reliably sealed (such as by welding or compression fitting) to prevent liquid nitrogen leakage, while also having a certain degree of flexibility to adapt to displacement and vibration during construction.

[0032] II. Working Principle of a Secondary Opening and Sealing Construction Device for Liquid Nitrogen Freezing Holes in Pipe Jacking Engineering (1) Drilling stage First, the installation position of the orifice pipe 1 on the well wall 11 is determined by the steel reinforcement positioning piece 6. The orifice pipe 1 is inserted into the well wall and fixed with an annular steel plate 7 and bolts, thus initially sealing the orifice pipe 1 with the well wall 11. Then, a gate valve 2, a bypass gate valve 8, and a sealing device 3 are installed sequentially at the end of the orifice pipe 1. Hemp fibers 9 are filled into the gaps between the orifice pipe 1 and the gate valve 2, and between the sealing device 3 and the drill pipe 4, forming a preliminary seal. The drilling rig is started, and the drill pipe 4 passes through the sealing device 3, the gate valve 3, and the orifice pipe 1, drilling into the formation. During the process, the pressure inside the hole is monitored by the bypass gate valve 8, and the sealing device 3 and hemp fibers 9 are used to prevent a large amount of soil and water from overflowing from the well wall, ensuring the smooth progress of the drilling operation.

[0033] (2) Lowering the pipe stage After drilling to the designed depth, drill rod 4 is removed, and stainless steel pipe 5 is installed and lowered into the freezing hole. Hemp fiber 9 is refilled at the connection gap between stainless steel pipe 5, borehole pipe 1, and sealing device 3. The mechanical structure of sealing device 3 compacts the hemp fiber 9, forming a reliable seal. One end of stainless steel pipe 5 is connected to liquid supply pipe 10. Gate valve 2 is closed, and test medium (such as compressed air) is introduced into the hole through bypass gate valve 8 for pressure testing to check the sealing performance. If the pressure is stable, the seal is good, and liquid nitrogen freezing can proceed. If leakage is found, the amount of hemp fiber 9 or the sealing device is adjusted until the seal is satisfactory. During liquid nitrogen freezing, the delivery of liquid nitrogen and the pressure inside the hole are controlled by gate valve 3 and bypass gate valve 8. Liquid nitrogen is delivered to the stratum using stainless steel pipe 5 to achieve soil freezing and reinforcement.

[0034] This utility model provides a secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking projects, which has the following advantages: With superior sealing performance, a multi-layer sealing structure is constructed through the synergistic effect of the orifice pipe, annular steel plate, sealing device and hemp fiber. The annular steel plate blocks the leakage channels inside and outside the well wall, and the sealing device and hemp fiber fill the connection gaps, effectively preventing liquid nitrogen leakage and formation water infiltration. Actual engineering verification shows that the sealing leakage rate is much lower than that of traditional devices, ensuring the effect of liquid nitrogen freezing and consolidating the formation and improving the safety of pipe jacking construction. The structure is rationally designed, with clear division of labor and tight connection among the components. The orifice pipe assembly realizes orifice positioning and initial sealing, the sealing assembly provides the main sealing force and pressure monitoring and adjustment functions, and the pipeline assembly meets the needs of drilling and liquid nitrogen transportation. This design makes the construction process clear, reduces the construction difficulty, improves the construction efficiency, and facilitates operation and maintenance by construction personnel. With strong environmental adaptability, this device can adapt to the requirements of different well wall thicknesses and formation conditions in pipe jacking projects. It can meet diverse construction needs by adjusting parameters such as the length of the orifice pipe and the amount of sealing material filling. At the same time, the stainless steel pipe, sealing device and other components have low temperature resistance and corrosion resistance, and can work stably for a long time in the harsh environment of liquid nitrogen freezing construction.

[0035] It should be noted that in the description of this utility model, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0036] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0037] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering, characterized in that, include: The system comprises an orifice pipe, a gate valve, a sealing device, a drill rod, and a liquid nitrogen delivery pipe. The orifice pipe, the gate valve, and the sealing device are sequentially connected to form a passage. The drill rod is configured to extend through the passage to the drilling location for drilling. The liquid nitrogen delivery pipe is fitted within the sealing device and works to deliver liquid nitrogen into the passage until it reaches the borehole. The gap between the orifice pipe and the gate valve is sealed with hemp fibers. The gap between the sealing device and the drill rod is also sealed with hemp fibers.

2. The secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering according to claim 1, characterized in that, The free end of the orifice pipe is equipped with a positioning element, which can position the orifice pipe and confirm its installation position on the well wall.

3. The secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering according to claim 1, characterized in that, An annular steel plate is fitted onto the orifice pipe. The annular steel plate is located on the outer side of the well wall of the orifice pipe. The annular steel plate is connected to the fixing structure on the side of the well wall by bolts, so that the annular steel plate is tightly attached to the well wall, which plays a role in initially fixing the position of the orifice pipe.

4. The secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering according to claim 1, characterized in that, The bypass pipeline of the gate valve is also equipped with a bypass gate valve, which can be used to monitor pressure changes in the orifice.

5. The secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering according to claim 1, characterized in that, The liquid nitrogen delivery pipe is made of stainless steel.

6. The secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering according to claim 1, characterized in that, The liquid nitrogen delivery pipe is also equipped with a liquid supply pipe, which connects the liquid nitrogen delivery pipe and the liquid nitrogen supply system, and can deliver the liquid nitrogen to the location to be frozen.

7. The secondary opening and sealing construction device for liquid nitrogen freezing holes in pipe jacking engineering according to claim 2, characterized in that, The positioning component is a rebar positioning component.

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