Novel cable trench with protection tube

Abstract

The utility model relates to the technical field of cable trenches, in particular to a novel cable trench with a protection tube, which comprises a trench body, a cover plate, a plurality of side tube bank brackets, a cable tube bank and a bottom tube bank pillow, the plurality of side tube bank brackets are fixed on two sides of the side wall of the cable trench, and the side tube bank brackets are arc-shaped brackets; the bottom calandria tube pillows are arranged at the bottom of the groove body side by side to form a tube pillow group, the side calandria supports and the tube pillow group are arranged in the groove body at preset intervals in the length direction of the cable groove, and cable calandria tubes are fixed in the groove body through the side calandria supports and the bottom calandria tube pillows. According to the novel cable trench with the protection pipe, the pipe trench is sustainable, cables are easy to lay, faults are easy to maintain, the cables are easy to replace, and secondary excavation is effectively avoided.

Description

Technical Field

[0001] The present application relates to the technical field of cable trenches, and in particular to a novel cable trench with a protective tube. Background Art

[0002] With the acceleration of urbanization in my country, the coverage and asset size of high-voltage power cables are increasing at an unprecedented rate. Typical power cable trenches include direct burial, drainage pipes, cable trenches, and tunnels. Cable trenches and drainage pipes are particularly common in 110kV power projects. Currently, the most widely used cable trench on the market is a cast-in-place reinforced concrete structure, primarily used for substation outgoing lines, along streets, on curved roads, and in locations with significant ground elevation changes.

[0003] Cable conduits are typically used at intersections of highways and railways, along narrow, busy urban roads, and in areas with minimal road curvature, such as crossing major roadblocks and avoiding specialized underground pipelines. Their advantages include reduced damage from external forces, unaffected cable laying, and simplified cable placement. However, their disadvantages include being unsuitable for areas with significant curvatures, as thermal expansion and contraction of the cable can cause fatigue in the metal sheath, resulting in poor heat dissipation and difficulty in cable replacement.

[0004] Reference Figure 1 The prefabricated pipe structure includes an inner lining layer and an outer layer. The inner lining layer is mainly used as the main loading part for the inserted conductors to protect the cables from moisture and pressure. The outer layer is reinforced concrete with a steel cage built into the concrete to protect the pipes from external factors such as collision and burning. The construction occupies a large area and relies on segmented assembly. The overall rigidity is poor. The docking process at the joints of prefabricated components has inherent defects, and the cables are easily scratched during installation. Both prefabricated cable trenches and prefabricated pipes have defects. The buried pipes and trough boxes are not able to resist external damage. Repeated excavation of cable trenches and trough boxes is difficult, and there is also the problem of difficulty in replacing old cables.

[0005] At the same time, there are many engineering projects that require or cannot lay cables at the same time, and secondary excavation of the backfilled and repaired cable trench is often required; cable trench construction and cable laying on the roadway takes a long time to occupy the road, the construction pressure is high, it is not conducive to traffic relief, and secondary excavation is extremely difficult; traditional concrete-encapsulated drainage pipes are difficult to remove, which limits cable maintenance and joint making. Transition wells must be set up within 50m, which greatly restricts large-scale application on the roadway and limits the advantages of rapid construction and repair of buried pipes. Utility Model Content

[0006] In order to overcome the shortcomings of related technologies, this application provides a new type of cable trench with protective pipes based on the combination of buried pipe technology and pipe laying technology, which is sustainable, easy to lay cables, easy to repair faults, and easy to replace cables.

[0007] The new cable trench with protective pipe provided in this application adopts the following technical solutions:

[0008] The new cable trench with protective pipes includes a trench body, a cover plate, side pipe brackets, cable pipes, and bottom pipe pillows. Multiple side pipe brackets are fixed on both sides of the side walls of the cable trench. The side pipe brackets are configured as arc-shaped brackets. Multiple bottom pipe pillows are arranged side by side at the bottom of the trench body to form a pipe pillow group. The side pipe brackets and the pipe pillow group are arranged in the trench body at preset distances along the length direction of the cable trench. The cable pipes are fixed in the trench body through the side pipe brackets and the bottom pipe pillows.

[0009] Furthermore, the novel cable trench with protective tube adopts a U-shaped cross section.

[0010] Furthermore, the side walls, bottom plate and cover plate of the cable trench are made of reinforced concrete.

[0011] Furthermore, the side pipe arrangement bracket includes a side vertical beam and an arc-shaped bracket, the side vertical beam and the arc-shaped bracket are formed in one piece, and the side vertical beam is fixedly connected to the side wall of the cable trench by expansion bolts.

[0012] Furthermore, the cable conduits on the side conduit brackets are fixed with binding bands.

[0013] Furthermore, the bottom pipe pillows are arranged in a square shape with arc grooves at the four corners. The bottom pipe pillows are connected by pins, which are arranged in the middle of the side walls of the bottom pipe pillows. The pipe pillow groups are arranged in the trench body at intervals of three meters along the length of the cable trench.

[0014] Furthermore, the cable conduit includes a small tube used for the return line and a large tube at the bottom of the trench. The two arc-shaped grooves at the adjacent corners of the two bottom conduit pillows are merged to form a groove that fits the small tube. The small tube is directly placed on the arc-shaped groove merged at the corners of the two adjacent bottom conduit pillows.

[0015] Furthermore, the remaining gaps in the groove body are filled with sand to fix them.

[0016] Furthermore, the new type of cable trench with protective tube adopts hot welding, and the length of the trench is increased to more than 500 meters.

[0017] Furthermore, the cable conduit is an MPP pipe, an HDPE pipe or a C-PVC pipe.

[0018] In summary, this application includes at least one of the following beneficial technical effects:

[0019] 1. The trench is sustainable, the cables are easy to lay, the faults are easy to repair, the cables are easy to replace, and secondary excavation is effectively avoided.

[0020] 2. The side pipe bracket is optimized from the original straight line to an arc shape, which reduces the wall thickness of the trench, improves space utilization, optimizes the internal clearance and the wall thickness of the structure, and realizes groove optimization.

[0021] 3. The U-shaped cross-section eliminates the need for additional working wells, breaking through the length constraints of cast-in-place buried pipes. The civil engineering can basically achieve the same length of trench and pipe, ensuring the sustainability of the pipeline corridor.

[0022] 4. Cable laying, replacement and emergency repair are not restricted by the working well location, and the cable maintenance work can be carried out directly by entering the trench at any location.

[0023] 5. Flexible joint location setting. The side pipe bracket can be removed at any location of the structure to place the cable joint.

[0024] 6. More convenient construction. This system breaks away from the "pavement demolition - civil construction - cable laying - road repair" construction model and completely separates civil construction from electrical construction. Road repair can proceed directly after conventional civil construction is completed. Since the cable conduits are already fixed in the trench, subsequent cable laying can be carried out at any time as needed, greatly improving construction convenience, shortening construction time, and minimizing the impact on surrounding roads and the environment.

[0025] 7. Better heat dissipation performance. Conventional stacked type is enclosed concrete casting, while U-shaped type is filled with fine sand and has a larger cable accommodation space, which helps to improve the heat dissipation effect and ensure the long-term stable operation of the cable.

[0026] 8. The cable conduit can be directly replaced by opening the trench cover without reserving a spare conduit.

[0027] 9. After the trench is combined, the pipes in the cable trench are in direct contact with the bracket, and the cables are placed in the pipes. The strain fatigue of the cable metal sheath caused by temperature changes is greatly reduced.

[0028] 10. The bracket and pipe fixing method has been improved. The bracket in the trench adopts an arc bracket. Compared with the conventional angle steel bracket, it can better stabilize the center of gravity of the cable in the middle of the bracket. The pipe on the bracket is fixed with a binding belt, which can save the cost of clamps. The pipe pillow group is set in the trench body at intervals of three meters along the length of the cable trench.

[0029] 11. Considering the situation where the cable segments adopt single-point grounding and return line, the small tube used for the return line required for each cable is directly placed on the arc groove merged at the corners of two adjacent bottom pipe pillows, and the remaining gaps in the groove are filled with sand to fix it.

[0030] 12. Pipe connection optimization. The grooved pipes are hot-melt welded, which has the advantages of no misalignment at the connection, full sealing, good longitudinal connection rigidity, and easy modification to increase the current carrying capacity.

[0031] 13. The idea of ​​combining trenches and pipes is adopted to form an overall structure that is soft inside and hard outside. By improving the quality of cable trenches, the protection of pipes and cables is far superior to that of cast-in-place buried pipe encapsulation structures, achieving double insurance in the protection of cables and cable conduits, and realizing the sustainability of trenches. The long length of cable conduits makes it easy to lay and replace cables. The optimization of the trench cross-section makes faults easy to repair, and cable laying can be carried out in the conduit manner. At the same time, the cable trench has the openable characteristics, which is convenient for maintenance and joint making. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is an existing poured concrete pipe construction structure.

[0033] Figure 2 It is a schematic cross-sectional view of the overall structure of this application.

[0034] Explanation of the accompanying symbols: 1. Trench body; 2. Cover plate; 3. Side pipe bracket; 4. Cable pipe; 5. Bottom pipe pillow; 6. Cable trench side wall; 7. Bottom plate; 9. Small pipe; 10. Large pipe; 14. Road structure layer; 11. Reinforced concrete; 12. Trench cover plate; 13. Concrete; 15. Reinforcement cage. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1 This application is described in further detail.

[0036] The embodiment of the present application discloses a new type of cable trench with a protective tube. Figure 1 The new cable trench with protective pipes includes a trench body 1, a cover plate 2, side pipe brackets 3, cable pipes 4, and bottom pipe pillows 5. Multiple side pipe brackets 3 are fixed on both sides of the cable trench side walls 6. The side pipe brackets 3 are configured as arc-shaped brackets. Multiple bottom pipe pillows 5 are arranged side by side at the bottom of the trench body 1 to form a pipe pillow group. The side pipe brackets 3 and the pipe pillow group are arranged in the trench body 1 at a preset distance along the length direction of the cable trench. The cable pipes 4 are fixed in the trench body 1 through the side pipe brackets 3 and the bottom pipe pillows 5.

[0037] The cable trench side wall 6 is perpendicular to the bottom plate 7 , and the cable trench side wall 6 and the bottom plate 7 are integrally formed. The cable trench side wall 6 , the bottom plate 7 and the cover plate 2 are made of reinforced concrete material.

[0038] The side pipe racks 3 include side vertical beams and curved brackets, which are integrally formed. The side vertical beams are fixedly connected to the cable trench sidewalls 6 via expansion bolts. Multiple side pipe racks 3 are fixed to both sides of the cable trench sidewalls 6. In the embodiment of the present application, three side pipe racks 3 are provided on each side of the cable trench sidewalls 6. The side pipe racks 3 are fixedly connected to the cable trench sidewalls 6 via expansion bolts.

[0039] Related Technology: The clearance inside a conventional 110kV cable trench is 1420mm x 1290mm, the trench wall thickness is 240mm, and 100mm long trench feet are set on both sides of the trench bottom. The side pipe bracket 3 inside the trench is 350mm long. The side pipe bracket 3 is optimized from the original straight line to an arc shape, and the length is reduced from 350mm to 290mm. The net width of the cable trench is reduced from 1420mm to 1300mm, and the space utilization rate is improved by 8.5%. The trench wall thickness is reduced from 240mm to 200mm. Considering that the new trench-type buried pipe is mainly subjected to vertical loads, the original trench feet are eliminated. The side pipe bracket 3 adopts an arc bracket. Compared with conventional angle steel brackets, it can better stabilize the center of gravity of the cable in the middle of the bracket. The cable pipes 4 on the side pipe bracket 3 are fixed with binding tape, which can save the cost of clamps. The side pipe rack 3 is used to isolate the cables from external pressure, heavy load or other external forces, and can reduce damage to the cables caused by external factors, such as mechanical damage, chemical corrosion and human damage.

[0040] The new cable trench with protected conduits features a U-shaped cross-section, eliminating the need for additional work pits. This overcomes the limitations of cast-in-place buried conduit lengths and allows for the trench and conduit to be essentially the same length, ensuring the sustainability of the tunnel. Cable laying, replacement, and emergency repairs are not restricted by the location of work pits, allowing direct access to the trench for subsequent cable maintenance at any location. The connector wells can be flexibly positioned. The side conduit brackets (3) can be removed and placed at any point within the structure to accommodate cable connectors. This facilitates construction. By breaking away from the "pavement demolition - civil construction - cable laying - road repair" construction model, civil construction and electrical work can be completely separated. Road repairs can proceed directly after conventional civil construction is completed. Since the cable conduits (4) are already secured within the trench, subsequent cable laying can be performed at any time as needed. This significantly improves construction convenience, reduces construction time, and minimizes impacts on surrounding roads and the environment. It also offers improved heat dissipation. While conventional stacked-type construction utilizes enclosed concrete casting, the U-shaped type utilizes fine sand landfill and provides greater cable accommodation, which improves heat dissipation and ensures long-term, stable cable operation.

[0041] The bottom pipe pillows 5 are arranged in a square shape, with arc grooves at the four corners. The bottom pipe pillows 5 are connected by pins, which are arranged in the middle of the side walls of the bottom pipe pillows 5. The pipe pillow groups are arranged in the trench body 1 at intervals of three meters along the length of the cable trench. The cable pipes 4 include small tubes 9 for the return line and large tubes 10 at the bottom of the trench. The two arc grooves at the adjacent corners of the two bottom pipe pillows 5 are combined to form a groove that fits with the small tubes 9. In the embodiment of the present application, four bottom pipe pillows 5 are arranged on the bottom plate 7. The bottom pipe pillows 5 are connected by pins, and a pipe pillow group is arranged every three meters. Considering the situation where the cable segment adopts single-point grounding plus return line, the small tubes 9 used for the return line required for each cable are directly placed on the arc grooves combined at the corners of two adjacent bottom pipe pillows 5, and the remaining gaps in the trench are filled with sand and fixed. The cross-sectional view of the embodiment of the present application shows a total of ten large tubes 10 and three small tubes 9.

[0042] Cable conduits 4 preferably use MPP, HDPE, or C-PVC. By physically comparing these three types of conduits based on density, tensile strength, insulation, friction coefficient, corrosion resistance, and low / high temperature resistance, as well as their reliability, general construction methods, cost-effectiveness, and environmental friendliness, the three aforementioned cable conduits 4, which align with the principles of cost-effectiveness, durability, and reliability, were selected for this embodiment.

[0043] The existing technology uses concrete pouring to fix the drainage pipes in order to enhance their fixation. The present application adopts sand filling for fixation. Due to the sand filling fixation method, it is easy to maintain. Since the conventional drainage pipe type cannot replace the cable drainage pipe 4, a spare pipe must be reserved for each cable loop. The new cable trench with protective pipe is more convenient to replace the cable drainage pipe 4. The cable drainage pipe 4 can be directly replaced by uncovering the trench cover 2. The 12 200mm (inner diameter) cable drainage pipes 4 of the conventional three-circuit drainage pipe are reduced to 10 200mm (inner diameter) cable drainage pipes 4, which can reduce project investment, benefit environmental protection, and reduce waste.

[0044] The new cable trench with protective tube adopts hot welding to connect the cable conduit and 4 pipes. Its advantages are no staggered joints, full sealing, good longitudinal connection rigidity, and easy to improve the current carrying capacity.

[0045] Typically, roadway conduit is constructed in sections of 40 meters with a 5-meter cable trench, or 80 meters with a 10-meter cable trench. Given the traffic impact of roadway excavation and the length of cables required for repairs by operators, this new trench-type conduit with protective tube cable trench can increase the length of conventional 40-meter conduit to over 500 meters, accelerating roadway trench construction and road repairs while minimizing secondary excavation.

[0046] Preferably, 500 meters of drainage pipes are added with a 20-meter-long cable trench without supports, and the trench is fixed with sand to facilitate the use of joints during later emergency repairs, which can be used as a pipe end transition well.

[0047] Taking into account the height difference between the top of the grooved pipe end and the bottom of the joint well, a pipe mouth expansion arc section needs to be set at both ends of the joint well. According to the overall simulation calculation, it is about 6 meters long, increasing the original 11-meter length of the conventional single-loop joint well to 18 meters. The expansion arc section is added with two sets of cable fixing clamps to strengthen the stability of the cable laying position, which is selected as the joint well type.

[0048] The structural dimensions of the transition pit are consistent with those of the new cable trench with protective pipes. There are some minor differences in cable laying. For example, in a pit with a small angle bend, such as a 90° bend, the pipes on both sides of the trench wall and the pipe pillows 5 at the bottom of the trench are not considered for installation. Alternatively, when laying cables in the future, one end of the trench can be selected and the corresponding pipe removed to transform it into a transition pit or intermediate joint pit.

[0049] The cable trench + conduit arrangement offers slightly better current carrying capacity than the buried conduit arrangement, but inferior to the three-circuit cable trench. By adjusting the arrangement, this arrangement can achieve 937A for one circuit and 662A for the other two circuits under unequal loads. Under equal loads, the three circuits can reach 843A.

[0050] In addition, the trench + pipe type is adopted, and the trench can be replaced with materials with high water content to reduce the thermal resistance coefficient. The idle pipes can be filled with water to reduce the ambient ground temperature.

[0051] The implementation principle of a new type of cable trench with protective tube in this application is as follows:

[0052] The recommended fixed laying methods for cables are as follows:

[0053] (1) Open working wells are backfilled with sand and fixed, including turning working wells and intermediate transition wells;

[0054] (2) Waterproof and fireproof plugs are installed at both ends of the cable tube, and there is no filling in the tube;

[0055] (3) According to calculations, a curved transition section should be set where the pipe mouth enters the intermediate joint well, with a length of not less than 2.7m;

[0056] (4) Two cable fixing clamps are set on each side of each phase cable joint in the intermediate joint well;

[0057] (5) Fill the entire joint well with sand for fixation.

[0058] The combination of cable trench and U-shaped cable conduit offers the advantages of sustainable tunnel construction, easy cable laying, easy troubleshooting, and easy cable replacement. This represents a new cable construction method and revolutionizes cable laying methods. The trench and conduit are constructed in one go throughout their lifecycle, eliminating the need for repeated road excavation for the cable trench. This overcomes the length constraints of cast-in-place buried conduits (generally 40m sections), eliminating the need for additional work pits, and civil engineering can essentially achieve the same length for the trench and conduit. Cable laying, replacement, and repairs are not restricted by work pit locations, allowing flexible joint well placement and single-section trench and conduit installations up to 900m. The reinforced concrete trench is exterior-rigid and interior-flexible, significantly enhancing its resistance to external forces and ground subsidence compared to cast-in-place buried conduits. Low-thermal-resistance materials or water can be injected into the conduit, providing a variety of methods for increasing current carrying capacity.

[0059] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A new type of cable trench with protective tube, characterized by: The utility model comprises a groove body (1), a cover plate (2), a side pipe bracket (3), a cable pipe (4), and a bottom pipe pillow (5), wherein a plurality of side pipe brackets (3) are fixed on both sides of the side wall (6) of the cable groove, the side pipe brackets (3) are configured as arc-shaped brackets, and a plurality of bottom pipe pillows (5) are arranged side by side at the bottom of the groove body (1) to form a pipe pillow group, the side pipe brackets and the pipe pillow group are arranged in the groove body (1) at a preset distance along the length direction of the cable groove, and the cable pipe (4) is fixed in the groove body through the side pipe brackets (3) and the bottom pipe pillow (5).

2. The novel cable trench with protective tube according to claim 1 is characterized in that: The novel cable trench with protective tube adopts a U-shaped cross section.

3. The novel cable trench with protective tube according to claim 1 is characterized in that: The cable trench sidewalls (6), bottom plate (7) and cover plate (2) are made of reinforced concrete.

4. The novel cable trench with protective tube according to claim 2 is characterized in that: The side pipe rack bracket (3) comprises a side vertical beam and an arc-shaped bracket, the side vertical beam and the arc-shaped bracket are integrally formed, and the side vertical beam is fixedly connected to the cable trench side wall (6) via expansion bolts.

5. The novel cable trench with protective tube according to claim 4 is characterized in that: The cable drain pipe (4) on the side drain pipe bracket (3) is fixed with a binding belt.

6. The novel cable trench with protective tube according to claim 5 is characterized in that: The bottom pipe pillows (5) are arranged in a square shape, with arc grooves arranged at the four corners. The bottom pipe pillows (5) are connected by pins, which are arranged in the middle of the side walls of the bottom pipe pillows (5). The pipe pillow groups are arranged in the groove body (1) at intervals of three meters along the length direction of the cable trench.

7. The novel cable trench with protective tube according to claim 6 is characterized in that: The cable conduit (4) includes a small tube (9) used for the return line and a large tube (10) at the bottom of the trench. Two arc-shaped grooves at the adjacent corners of the two bottom conduit pillows (5) are combined to form a groove that fits the small tube (9). The small tube (9) is directly placed on the arc-shaped grooves at the corners of the two adjacent bottom conduit pillows (5).

8. The novel cable trench with protective tube according to claim 7 is characterized in that: The remaining spaces in the groove body (1) are filled with sand and fixed.

9. The novel cable trench with protective tube according to claim 8 is characterized in that: The new type of cable trench with protective tube adopts hot welding, and the length of the trench is increased to more than 500 meters.

10. The novel cable trench with protective tube according to claim 9 is characterized in that: The cable conduit (4) is an MPP pipe, an HDPE pipe or a C-PVC pipe.

Images