Pipeline for crossing fault area

Abstract

The invention belongs to the technical field of pipelines, and particularly relates to a pipeline for a cross-fault area. Comprising a plurality of steel cylinders which are arranged at intervals, a plurality of mounting holes parallel to the axial direction of each steel cylinder are formed in the side wall of each steel cylinder, the mounting holes in the steel cylinders are arranged in a one-to-one alignment mode, a memory metal rod is arranged in each set of aligned mounting holes in a penetrating mode, the memory metal rods are fixedly connected with the steel cylinders, and the memory metal rods are connected with the steel cylinders. A rubber cylinder is fixedly connected between every two adjacent steel cylinders, the memory metal rods are embedded in the side walls of the rubber cylinders, the inner walls of the steel cylinders and the inner walls of the rubber cylinders are coated with integrated first coatings, and the outer walls of the steel cylinders and the outer walls of the rubber cylinders are coated with integrated second coatings. The rubber cylinders are used for flexible connection between the steel cylinders, the displacement can be shared when the cross-fault pipeline has large displacement, the pipeline can adapt to dislocation difference of upper and lower discs, and the pipeline is prevented from being damaged.

Description

Technical Field

[0001] This invention belongs to the field of pipeline technology, and specifically relates to a pipeline for crossing fault zones. Background Technology

[0002] The compression between continental plates creates numerous fault zones. As infrastructure construction expands, the construction of large-scale drainage pipelines inevitably traverses these fault areas. Fault displacement can cause permanent deformation of the strata, potentially leading to cracking, damage, or even collapse of the drainage pipelines. This can also trigger secondary disasters such as floods and environmental pollution, resulting in significant economic losses.

[0003] Under seismic loads, pipelines crossing fault zones may experience various hazard modes, including tensile fracture, local instability, and flexural fatigue fracture. In cases of intersecting faults, the shear forces induced by displacement of the hanging wall and footwall can cause vertical and axial deformation of the pipeline, and may also lead to horizontal torsion. Furthermore, the longitudinal response induced by the earthquake can cause tensile and compressive stresses induced by compressive waves and structural torsional deformation caused by shear waves, ultimately leading to pipeline failure.

[0004] In light of the above, analyzing the interaction mechanism between cross-fault drainage pipelines and surrounding rock, as well as the deformation and failure characteristics of tunnels, and conducting research on seismic resistance measures for drainage pipelines in fault fracture zones, has significant scientific and engineering application value. Currently, large pipelines are mainly concrete pipelines, and the main seismic mitigation measures for large cross-fault pipelines traversing fault fracture zones include the flexible pipe ring method and the flexible joint method.

[0005] The flexible pipe ring method uses highly ductile pipe materials, such as HDPE (high-density polyethylene) pipes. Their extremely high ductility and flexibility allow them to withstand huge tensile and bending deformations without breaking. Even if local buckling occurs, they can still maintain a certain flow capacity.

[0006] The flexible joint method utilizes flexible longitudinal joints, such as spherical joints, to connect pipelines. When a fault tunnel undergoes displacement and deformation, the damage to the tunnel structure tends to concentrate locally or at the longitudinal joints of the segment rings. The flexible joints can absorb deformation and energy, reducing the impact of fault displacement. Flexible joints not only reduce stress on the segments but also increase the overall flexibility of the tunnel within the fault's influence range. Even if fault displacement occurs, the presence of flexible joints will limit tunnel damage to a finite area, thus avoiding overall damage and reducing maintenance and repair costs.

[0007] The wide-shallow trench and loose backfill method involves excavating trenches wider and shallower than usual in fault zones. This provides ample space for future pipeline deformation, preventing the pipeline from being "locked in" by the surrounding hard soil. Loose, uncompacted sand or gravel without large particles is then used for backfilling. This material exerts less constraint on the pipeline, allowing it relatively free movement and bending during fault displacement.

[0008] The above are commonly used anti-faulting measures in cross-fault drainage pipelines, but they still have the following disadvantages and deficiencies: HDPE pipes are flexible pipes, and their structural stability is highly dependent on the lateral support of the surrounding soil. During fault activity, the strata may undergo severe deformation, collapse, or develop cavities, leading to the failure of the pipe's support.

[0009] The main drawback of using concrete pipes for fault crossings is their high brittleness and poor ductility. Fault displacement causes the pipes to experience tensile, bending, and shear deformation. Concrete, being a brittle material, has very small ultimate tensile and bending strains (typically only about 1 / 10 that of steel). Under small forced displacements, it will crack, fracture, or even shatter, unable to absorb or adapt to fault displacement through plastic deformation. Furthermore, concrete pipes have insufficient capacity for joint deformation adaptation. Even with flexible rubber ring joints, the allowable angular and multi-directional displacement is usually limited (generally only a few centimeters to tens of centimeters of deflection and tension). For active faults that may experience displacements of several meters or even greater, conventional joints will fail rapidly, leading to detachment, leakage, or damage.

[0010] The damping design of flexible joints distributes fault dislocations evenly across the joints with the greatest deformation. However, the application of flexible joints is limited when the fault width is small. Furthermore, existing research has not yet formed a complete system, and construction schemes are still immature.

[0011] In the case of wide and shallow trenches and loose backfilling, the loose backfill area is prone to uneven settlement due to groundwater erosion or self-consolidation, which may lead to new bending stress or slope changes in the pipeline and affect gravity flow.

[0012] Furthermore, all three methods mentioned above suffer from high costs and complex construction techniques and procedures. A single seismic resistance measure is often insufficient to meet engineering requirements and cannot cope with the damage to pipeline structures caused by fault displacement.

[0013] Based on the above problems, there is an urgent need to design a pipeline for crossing fault regions to solve the problem of uneven settlement across faults. Summary of the Invention

[0014] To address the problems existing in the prior art, this invention provides a pipeline for crossing fault regions, and specifically discloses the following technical solutions: A pipeline for crossing a fault zone includes a plurality of steel cylinders spaced apart. Each steel cylinder has a plurality of mounting holes parallel to its axial direction on its sidewall, and the mounting holes on the plurality of steel cylinders are aligned one-to-one. A shape memory metal rod is inserted into each set of aligned mounting holes, and the shape memory metal rod is fixedly connected to each steel cylinder. A rubber cylinder is fixedly connected between every two adjacent steel cylinders. The shape memory metal rod is embedded in the sidewall of the rubber cylinder. The inner walls of the plurality of steel cylinders and the plurality of rubber cylinders are coated with an integral first coating, and the outer walls of the plurality of steel cylinders and the plurality of rubber cylinders are coated with an integral second coating.

[0015] Furthermore, the spacing between any two adjacent steel cylinders is the same.

[0016] Furthermore, the mounting holes are evenly distributed along the circumference of the steel cylinder.

[0017] Furthermore, the inner wall of the steel cylinder is flush with the inner wall of the rubber cylinder, and the outer wall of the steel cylinder is flush with the outer wall of the rubber cylinder.

[0018] Furthermore, the outer surface of the shape memory metal rod is in close contact with the wall of the mounting hole, and the shape memory metal rod is welded and fixed to the steel cylinder.

[0019] Furthermore, the length of the shape memory metal rod is equal to the total length of all the steel cylinders and all the rubber cylinders.

[0020] Furthermore, both the first coating and the second coating are polyurethane coatings applied using a cross-hatching method.

[0021] Furthermore, the thickness of the first coating is the same as the thickness of the second coating, both being 4-6 mm.

[0022] Furthermore, the rubber cylinder is made of rubber with a shear modulus of 1 MPa and a hardness of 70 (IHRD).

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: As a flexible connection between steel cylinders, the rubber sleeve can distribute the displacement when the pipeline across a fault undergoes large displacement. Even when the ultimate state is reached, the damage to the pipeline structure is only concentrated in a localized area, namely the rubber sleeve, thus avoiding overall pipeline failure. When the fault dislocation is small, the rubber sleeve adapts to the fault dislocation through its own flexibility and ductility. When the fault dislocation is large enough, the rubber sleeve attracts and releases the fault energy through its own destruction. This design allows the pipeline to adapt to the dislocation difference between the upper and lower plates, preventing it from being damaged.

[0024] The shape memory metal rods arranged along the circumference provide the pipeline with a certain amount of additional stiffness, making the pipeline have greater lateral stiffness than ordinary concrete pipe segments under static conditions. Moreover, the arrangement of shape memory metal rods can improve the overall stability of the pipeline when subjected to displacement deformation: when fault displacement occurs, the shape memory metal rods and steel cylinders limit the displacement of the rubber cylinder to a certain extent, so that the pipeline will not experience excessive lateral displacement.

[0025] Under earthquake conditions caused by faults, the composite elastic body composed of steel and rubber cylinders exhibits excellent coordinated deformation performance, which can weaken the constraint force of the surrounding strata on the rest of the pipeline. The energy transmitted to the pipeline structure by an earthquake is a constant value; by dissipating some of this energy through the steel and rubber cylinders, the energy acting on the structure is greatly reduced, thus protecting the overall pipeline structure under earthquake action. After an earthquake, the elastic potential energy stored inside the rubber cylinders allows the pipeline to automatically return to its original position. Furthermore, the shape memory metal rods have excellent fatigue resistance, allowing for multiple deformations without loss of efficiency.

[0026] The coating uses polyurethane, which has excellent elasticity and fits the flexible structure of the pipe, adapting to cracking and deformation of the substrate. It also has strong adhesion to rubber and metal, providing a firm bond and preventing peeling or detachment. This allows it to deform with the rubber cylinder during faulting without cracking or falling off. The coating is integrally formed without seams, eliminating the risk of leakage and pipe corrosion at joints. The polyurethane coating is non-toxic and can isolate the toxicity of rubber, preventing water pollution. The polyurethane coating features a flexible, wear-resistant film, stable chemical properties, and corrosion resistance, effectively preventing steel corrosion. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0028] Figure 2 This is a top view of the present invention.

[0029] Figure 3 This is a schematic diagram of the assembly of the steel cylinder and the shape memory metal rod in this invention.

[0030] 1-First coating, 2-Memory metal rod, 3-Steel cylinder, 4-Rubber cylinder, 5-Second coating. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Reference Figure 1-3 A pipeline for crossing a fault zone includes several steel cylinders 3 spaced apart. Each steel cylinder 3 has several mounting holes parallel to its axial direction on its side wall, and the mounting holes on the steel cylinders 3 are aligned one by one. A memory metal rod 2 is inserted into each set of aligned mounting holes, and the memory metal rod 2 is fixedly connected to each steel cylinder 3. A rubber cylinder 4 is fixedly connected between every two adjacent steel cylinders 3. The memory metal rod 2 is embedded in the side wall of the rubber cylinder 4. The inner walls of the steel cylinders 3 and the rubber cylinders 4 are coated with an integral first coating 1, and the outer walls of the steel cylinders 3 and the rubber cylinders 4 are coated with an integral second coating 5.

[0033] In this embodiment, the pipe is used to replace the concrete pipe that crosses the fault zone. Both ends of the pipe can be fixedly connected to the concrete pipe. The number of steel cylinders 3 and rubber cylinders 4 required for the pipe can be determined according to the actual length of the fault it crosses.

[0034] In this embodiment, the spacing between any two adjacent steel cylinders 3 is the same.

[0035] In this embodiment, several mounting holes are evenly distributed along the circumference of the steel cylinder 3, which ensures a certain lateral stiffness and also makes the pipe subjected to uniform force in the circumference, so as not to cause large stress concentration in a certain place.

[0036] In this embodiment, the inner wall of the steel cylinder 3 is flush with the inner wall of the rubber cylinder 4, and the outer wall of the steel cylinder 3 is flush with the outer wall of the rubber cylinder 4, so as to form a tube with smooth inner and outer walls without protrusions.

[0037] In this embodiment, the outer surface of the memory metal rod 2 is in close contact with the wall of the mounting hole, and the memory metal rod 2 is welded and fixed to the steel cylinder 3 to prevent the memory metal rod 2 from sliding, rotating and shaking relative to the mounting hole.

[0038] In this implementation, all the shape memory metal rods 2 and steel cylinders 3 are welded together and then the rubber cylinder 4 is cast as a whole. Then, the steel cylinder 3 and the rubber cylinder 4 are tightly bonded together through high temperature and high pressure vulcanization.

[0039] In this embodiment, the length of the shape memory metal rod 2 is equal to the total length of all the steel cylinders 3 and all the rubber cylinders 4.

[0040] In this embodiment, both the first coating 1 and the second coating 5 are polyurethane coatings applied using a cross-hatching method. The polyurethane coating has excellent elasticity, allowing it to adapt to cracking and deformation of the substrate, making the first coating 1 and the second coating 5 less prone to cracking due to pipe deformation and misalignment. The first coating 1 is located on the inner side of the pipe, preventing corrosion of the inner pipe surface and avoiding rubber contamination during water transport; the second coating 5 is located on the outer side of the pipe, primarily for waterproofing and preventing corrosion of the outer pipe wall.

[0041] In this embodiment, the thickness of the first coating 1 is the same as the thickness of the second coating 5, both being 4-6 mm.

[0042] In this embodiment, the rubber cylinder 4 is made of rubber with a shear modulus of 1 MPa and a hardness of 70 (IHRD). The high shear modulus and hardness of the rubber ensure a large shear yield stress. This allows the rubber to undergo significant displacement without failure under fault dislocation conditions. Simultaneously, the rubber possesses excellent energy dissipation properties, enabling it to function as a seismic damping agent. The dimensions of the rubber cylinder 4 are determined based on the actual dimensions of the engineering project.

[0043] Before constructing large-scale drainage pipes, the steel cylinder 3, rubber cylinder 4, and shape memory metal rod 2 need to be prefabricated. The prefabricated components are then assembled to complete the pipe splicing in this invention. During construction, a standardized concrete drainage pipe construction mode is adopted. When the pipe enters the area of ​​fault displacement, the pipe of this invention is used instead, and the pipes are connected by butt-welded pipe joints.

[0044] As a flexible connection between the steel cylinders 3, the rubber cylinder 4 can distribute the displacement when the pipeline across the fault undergoes large displacement. Even when the ultimate state is reached, the damage to the pipeline structure is only concentrated in a local part of the structure, namely the rubber cylinder, thus avoiding overall pipeline failure. When the fault dislocation is small, the rubber cylinder 4 adapts to the fault dislocation through its own flexibility and ductility. When the fault dislocation is large enough, the rubber cylinder 4 attracts and releases the fault energy through its own destruction. This design allows the pipeline to adapt to the dislocation difference between the upper and lower plates, preventing it from being damaged.

[0045] The shape memory metal rods 2 arranged along the circumference provide the pipeline with a certain additional stiffness, making the pipeline have greater lateral stiffness than ordinary concrete pipelines under static conditions. Moreover, the arrangement of shape memory metal rods 2 can improve the overall stability of the pipeline when subjected to displacement deformation: when fault displacement occurs, the shape memory metal rods 2 and steel cylinder 3 limit the displacement of rubber cylinder 4 to a certain extent, so that the pipeline will not undergo excessive lateral displacement.

[0046] Under earthquake conditions caused by faults, the composite elastic body composed of steel cylinder 3 and rubber cylinder 4 exhibits excellent coordinated deformation performance, which can weaken the constraint force of the surrounding strata on the rest of the pipeline. The energy transmitted to the pipeline structure system by an earthquake is a constant value. A portion of this energy is dissipated through the energy dissipation of steel cylinder 3 and rubber cylinder 4, significantly reducing the energy acting on the structure and thus protecting the overall pipeline structure under earthquake conditions. After an earthquake, the elastic potential energy stored inside rubber cylinder 4 allows the pipeline to automatically return to its original position. Furthermore, the shape memory metal rod 2 has excellent fatigue resistance, allowing for multiple deformations without loss of efficiency.

[0047] The coating uses polyurethane, which has excellent elasticity and fits the flexible structure of the pipe, adapting to cracking and deformation of the substrate. It also has strong adhesion to rubber and metal, ensuring a firm bond and preventing peeling or detachment. This allows it to deform with the rubber sleeve during faulting without cracking or falling off. The coating is integrally formed without seams, eliminating the risk of leakage and pipe corrosion at joints. The polyurethane coating is non-toxic and can isolate the toxicity of rubber, preventing water pollution. The polyurethane coating features a flexible, wear-resistant film, stable chemical properties, and corrosion resistance, effectively preventing steel corrosion.

[0048] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A pipeline for crossing fault zones, characterized in that, The device includes several steel cylinders spaced apart. Each steel cylinder has several mounting holes parallel to its axial direction on its side wall, and the mounting holes on the steel cylinders are aligned one-to-one. A memory metal rod is inserted into each set of aligned mounting holes, and the memory metal rod is fixedly connected to each steel cylinder. A rubber cylinder is fixedly connected between every two adjacent steel cylinders. The memory metal rod is embedded in the side wall of the rubber cylinder. The inner walls of the steel cylinders and the rubber cylinders are coated with an integral first coating, and the outer walls of the steel cylinders and the rubber cylinders are coated with an integral second coating.

2. A pipeline for crossing fault regions according to claim 1, characterized in that, The spacing between any two adjacent steel cylinders is the same.

3. A pipeline for crossing fault zones according to claim 1, characterized in that, The mounting holes are evenly distributed along the circumference of the steel cylinder.

4. A pipeline for crossing fault zones according to claim 1, characterized in that, The inner wall of the steel cylinder is flush with the inner wall of the rubber cylinder, and the outer wall of the steel cylinder is flush with the outer wall of the rubber cylinder.

5. A pipeline for crossing fault zones according to claim 1, characterized in that, The outer surface of the shape memory metal rod is in close contact with the wall of the mounting hole, and the shape memory metal rod is welded and fixed to the steel cylinder.

6. A pipeline for crossing fault regions according to claim 1, characterized in that, The length of the shape memory metal rod is equal to the total length of all the steel cylinders and all the rubber cylinders.

7. A pipeline for crossing fault regions according to claim 1, characterized in that, Both the first coating and the second coating are polyurethane coatings applied using a cross-hatching method.

8. A pipeline for crossing fault regions according to claim 7, characterized in that, The thickness of the first coating is the same as that of the second coating, both being 4-6 mm.

9. A pipeline for crossing fault regions according to claim 1, characterized in that, The rubber cylinder is made of rubber with a shear modulus of 1 MPa and a hardness of 70 IHRD.

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