Large-span three-dimensional cable net system, construction method of system and flexible photovoltaic support

Abstract

The invention provides a large-span three-dimensional cable net system, a construction method of the system and a flexible photovoltaic support. The large-span three-dimensional cable net system comprises long-direction installation cables extending in the long-span direction, a plurality of short-span double-layer cable trusses arranged at intervals in the long-span direction and precast piles located at the ends and in the middle. The short-span double-layer cable truss comprises an upper-layer stabilizing cable (arranged in an upward convex arc shape) and a lower-layer pressure-bearing cable (arranged in a downward concave arc shape), and the upper-layer stabilizing cable and the lower-layer pressure-bearing cable are connected through vertically-arranged steel supporting rods to form a plane cable truss structure. The positions of the short-span double-layer cable trusses in the long-span direction correspond to supporting points of the long-direction installation cables, and the long-direction installation cables transversely span the short-span double-layer cable trusses and are connected with the short-span double-layer cable trusses at the top and bottom nodes of the in-span triangular supports. The end prefabricated piles are connected with the triangular support through the pile top stand columns, and the two ends of the triangular support are connected with the length-direction installation cable and the cable-stayed component correspondingly. The adjacent precast piles in the middle are connected through inclined supports which are arranged in a crossed mode. The invention has the characteristics of high adaptability, light weight and easy installation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable net system construction, in particular to a large-span three-dimensional cable net system, a construction method of the system and a flexible photovoltaic support. BACKGROUND

[0002] With the rapid development of renewable energy technology, photovoltaic power generation systems have been widely used in the fields of construction and engineering. Flexible photovoltaic support systems based on tension cables have gradually become one of the important solutions for large-span photovoltaic installation due to their lightweight and strong adaptability. Such systems usually consist of high-strength steel cables, connecting components and photovoltaic modules, and form a stable spatial structure through pre-tensioning to support photovoltaic panels.

[0003] Currently, flexible photovoltaic support systems mainly adopt two structural forms: single-layer cable and double-layer cable. The single-layer cable system directly supports photovoltaic modules through a single layer of prestressed steel cables, which has the advantages of simple structure and low cost. However, in practical applications, due to the small vertical stiffness of the single-layer cable system, it will produce large deformation under the combined action of the self-weight of the photovoltaic modules and wind load, which makes it only suitable for small-span application scenarios.

[0004] To solve the problem of insufficient stiffness of the single-layer cable system, the double-layer cable system emerged. This system adds an arc-shaped bearing cable below the photovoltaic installation cable, and the upper and lower cables work together to enhance the overall stiffness of the structure. This design significantly improves the system's load-carrying capacity for gravity loads, making it suitable for larger-span applications. However, when subjected to upward wind suction, the bearing cable will lose its pre-tension and fail, resulting in significant upward deformation of the system and poor wind suction resistance performance. SUMMARY

[0005] The present application aims to provide a large-span three-dimensional cable net system, a construction method of the system and a flexible photovoltaic support to alleviate the above technical problems in the prior art.

[0006] In a first aspect, the present application provides a large-span three-dimensional cable net system, comprising long-span installation cables extending along the long-span direction, a plurality of short-span double-layer cable trusses arranged along the long-span direction, and precast piles at the end and middle parts. Each short-span double-layer cable truss comprises an upper stable cable and a lower bearing cable, the upper stable cable is arranged in an upward convex arc shape, and the lower bearing cable is arranged in a downward concave arc shape. The upper stable cable and the lower bearing cable are connected by vertically arranged steel struts to form a planar cable truss structure. The position of each short-span double-layer cable truss in the long-span direction corresponds to a support point of the long-span installation cable, the long-span installation cable transversely spans multiple short-span double-layer cable trusses, and is connected to the short-span double-layer cable truss at the top node and the bottom node of the in-span triangle brace; The end precast pile is connected to the triangular support through a pile top column, and the triangular support is connected to the long-span installation cable and the cable-stayed component at two ends; the adjacent precast piles in the middle are connected through the cross arrangement of the inclined support.

[0007] In an optional embodiment, the short-span double-layer cable truss further comprises an in-span intermediate connecting rod, the two ends of the in-span intermediate connecting rod are respectively connected to the upper stable cable and the lower bearing cable, and the in-span intermediate connecting rod is arranged on both sides of the steel support rod in the vertical direction.

[0008] In an optional embodiment, the in-span triangle brace is composed of three rod members to form an inverted triangular structure, the top two nodes of the in-span triangle brace are respectively connected to the long-span installation cable, the bottom node is connected to the lower bearing cable, and the top end of the triangle brace top extension rod is connected to the upper stable cable.

[0009] In an optional embodiment, the top of the end precast pile is provided with a pile top beam, the pile top beam is provided with two pile top columns with different heights, and the two pile top columns are respectively connected to the two end points of the triangular support.

[0010] In an optional embodiment, the triangular support is a triangular rigid frame structure, the top two end points of the triangular support are respectively connected to the long-span installation cable and one end of the cable-stayed component, and the other end of the cable-stayed component extends downward and is connected to the precast pile.

[0011] In an optional embodiment, the two ends of the cable-stayed component are connected to the triangular support and the precast pile in a hinged manner.

[0012] In an optional embodiment, the long-span installation cable is provided with a node at each installation position corresponding to a photovoltaic module, and the load is transmitted to the cable body through a virtual rod.

[0013] In an optional embodiment, the sag between the upper stable cable and the lower bearing cable is determined in advance through a structural analysis model, and the sag height of the lower bearing cable in the short-span direction is adjustable.

[0014] In a second aspect, the application provides a construction method of a large-span three-dimensional cable net system, comprising: The span of the short-span direction and the long-span direction is determined according to the actual site conditions; According to the span, a structure analysis model is established, the long-direction installation cable extending along the long-span direction, the plurality of short-span double-layer cable trusses arranged along the long-span direction and the prefabricated piles at the end and the middle are arranged in the structure analysis model; each short-span double-layer cable truss comprises an upper stable cable and a lower pressure-bearing cable, the upper stable cable is arranged in an upper convex arc shape, the lower pressure-bearing cable is arranged in a lower concave arc shape, and the upper stable cable and the lower pressure-bearing cable are connected by the vertically arranged steel support rod to form a planar cable truss structure; the long-direction installation cable transversely spans the plurality of short-span double-layer cable trusses and is connected with the short-span double-layer cable trusses at the top node and the bottom node of the inner triangle brace, and the positions of the short-span double-layer cable trusses in the long-span direction correspond to the support points of the long-direction installation cable. According to the initial stress and internal force of the upper stable cable, the lower pressure-bearing cable and the long-direction installation cable, the cross-sectional form and size of the cable body and the steel member connected with the cable body and constituting the overall force system are determined. According to the geological exploration information and the force data of the end node, the sag height of the lower pressure-bearing cable and the cross-sectional parameters of the cable-stayed member are adjusted, the length and the cross-sectional specification of the prefabricated pile are determined, so as to construct the large-span three-dimensional cable net system.

[0015] In a third aspect, the present application provides a flexible photovoltaic support comprising the large-span three-dimensional cable net system of any one of the preceding embodiments, the large-span three-dimensional cable net system being used as a support structure for installing photovoltaic components.

[0016] The large-span three-dimensional cable net system, the construction method of the system and the flexible photovoltaic support provided by the present application effectively reduce the vertical deformation of the long-direction installation cable by arranging the short-span double-layer cable truss as the intermediate support of the long-direction installation cable, improve the overall stiffness and carrying efficiency of the system, and solve the problem of excessive deformation of the traditional single-layer or double-layer cable system under large span; the upper convex stable cable and the lower concave pressure-bearing cable work cooperatively to form a self-balancing force system in combination with the steel support rod, significantly enhance the wind suction resistance, and overcome the defect of poor wind stability of the double-layer cable system; the long-direction cable and the short-span cable truss are spatially linked, the force transmission path is clear, the material is fully utilized, and the problems of high steel consumption and complex node caused by excessive dependence on steel members in the fish-belly type or beam string structure system are avoided; the prefabricated piles at the end and the middle are connected through the triangular support, the cable-stayed member and the cross support, the anchoring reliability is improved and the local stress concentration is reduced, and the overall structure has the characteristics of high adaptability, light weight and easy installation. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1A three-dimensional structural schematic diagram of a large-span three-dimensional cable net system provided by an embodiment of the present application; Figure 2 A short-span double-layer cable truss structure schematic diagram provided by an embodiment of the present application; Figure 3 A long-span structure schematic diagram provided by an embodiment of the present application; Figure 4 An end-column structure schematic diagram provided by an embodiment of the present application; Figure 5 A middle-column structure schematic diagram provided by an embodiment of the present application; Figure 6 A flow chart of a construction method of a large-span three-dimensional cable net system provided by an embodiment of the present application; Figure 7 A flow chart of a specific construction method of a large-span three-dimensional cable net system provided by an embodiment of the present application.

[0019] The drawings show: 1-longitudinal installation cable; 2-upper stabilizing cable; 3-lower pressure-bearing cable; 4-in-span triangular strut; 5-in-span intermediate connecting rod; 6-triangular support; 7-pile top column; 8-pile top beam; 9-precast pile; 10-middle-column X-shaped support; 11-cable-stayed component. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0022] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, thus, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0023] The embodiments of the present application provide a large-span three-dimensional cable net system, referring to Figure 1The structural three-dimensional diagram of the large-span cable net system shown, including the long-span installation cable (also known as the long-span cable) extending along the long-span direction, a plurality of short-span double-layer cable trusses arranged along the long-span direction, and precast piles at the end and middle parts; the system constitutes a spatially cooperative prestressed cable net structure system, which is suitable for large-span photovoltaic support engineering scenarios.

[0024] Among them, the short-span double-layer cable truss is arranged along the short-span direction and spans the entire short span, serving as a key transverse load-bearing unit supporting the long-span installation cable. Each short-span double-layer cable truss includes an upper stabilizing cable and a lower pressure-bearing cable. The upper stabilizing cable is arranged in an upward convex arc shape and is mainly used to resist upward tension generated under wind suction load, preventing overall instability of the structure; the lower pressure-bearing cable is arranged in a downward concave arc shape and mainly bears the tension deformation generated by vertical loads such as the self-weight of photovoltaic modules, snow load, and downward wind pressure. The two cables are connected by a plurality of vertically arranged steel struts to form a cable truss structure with planar rigidity. See Figure 2 The short-span double-layer cable truss structure diagram shown effectively improves the bending and torsional resistance in the short-span direction and achieves mechanical coupling between the upper and lower cables.

[0025] The position of each short-span double-layer cable truss in the long-span direction corresponds to the support point of the long-span installation cable 1, i.e., the long-span installation cable 1 transversely spans multiple short-span double-layer cable trusses and is physically connected to the short-span double-layer cable truss at the top node and bottom node of the in-span triangle brace 4. See Figure 3 The long-span structure diagram shown, the long-span installation cable 1 continuously extends along the long-span direction, directly bearing the photovoltaic modules and being fixed to the cable body through a special clamp; it is lifted by multiple short-span double-layer cable trusses and anchored to the top node and bottom node of the in-span triangle brace 4, thereby forming a multi-point support force mode, significantly reducing the vertical deflection of the long-span cable under the action of gravity and wind load, and improving the overall stiffness and anti-deformation ability of the system.

[0026] In addition, the system also includes precast piles 9 arranged at the end and middle parts of the structure, serving as the main counterforce foundation of the entire cable net system and bearing complex internal forces transferred by cable tension. See Figure 4 The end frame structure diagram shown, the end precast pile 9 is connected to the triangle bracket 6 through the pile top column 7, and the triangle bracket 6 serves as a key force transmission component with its top two endpoints connected to the long-span installation cable 1 and the inclined cable member 11. This arrangement enables the end node to simultaneously transmit axial tension, bending moment, and shear force, achieving effective anchoring and balancing of cable force.

[0027] Further, see Figure 5The middle structure schematic diagram shows that the middle adjacent precast piles 9 are connected through the cross arranged oblique supports, that is, the middle X-shaped supports 10, which enhances the lateral stiffness and torsional resistance of the middle structure region and prevents the out-of-plane instability phenomenon caused by asymmetric load.

[0028] In summary, the embodiment constructs an efficient, lightweight, and highly adaptive spatial three-dimensional cable net structure system by using the short-span double-layer cable truss as an intermediate support, the long-directional installation cable 1 as a main load-bearing component, and the end and middle structure pile foundation as a counterforce system. After applying bidirectional prestress, the structure forms a self-balanced structure, which can maintain good mechanical properties under various load conditions and their combinations, and is particularly suitable for large photovoltaic power station construction in complex terrain environments such as Gobi, desert, beach, and water surface.

[0029] Further, in an optional embodiment, the short-span double-layer cable truss further includes an intra-span intermediate connecting rod 5, the two ends of which are respectively connected with the upper stable cable 2 and the lower pressure-bearing cable 3 and are arranged on both sides of the steel support rod in the vertical direction. Referring to Figure 2 The short-span double-layer cable truss structure schematic diagram shows that the intra-span intermediate connecting rod 5 is arranged on both sides of the intra-span triangular support 4, which is symmetrically distributed, and its main function is to enhance the lateral stability between the upper and lower cables and prevent local buckling or deviation.

[0030] Further, the two ends of the intra-span intermediate connecting rod 5 are connected in a hinged manner, allowing a certain degree of rotational freedom to adapt to the small displacement changes of the cable body under different load conditions, reduce the accumulation of secondary stress, and improve the durability of the structure. This structure takes into account the structural stiffness and construction tolerance, which helps to improve the overall performance of the short-span double-layer cable truss, especially under temperature changes or long-term service conditions.

[0031] In an embodiment, the intra-span triangular support 4 is composed of three rod members to form an inverted triangular structure, the top two nodes of the intra-span triangular support 4 are connected with the long-directional installation cable 1, the bottom node is connected with the lower pressure-bearing cable 3, and the extension rod member is connected with the upper stable cable 2. Referring to Figure 2 The short-span double-layer cable truss structure schematic diagram shows that the inverted triangular structure has excellent spatial force transmission path and can efficiently disperse the concentrated load of the long-directional installation cable 1 to the upper and lower cable bodies.

[0032] The nodes of the intra-span triangular support 4 are connected in a rigid manner to ensure that the node area has sufficient bending resistance and integrity, avoiding structural failure due to node loosening. This structure not only improves the local stiffness of the short-span cable truss, but also enhances its ability to resist asymmetric load, so that the entire cable net system can maintain geometric stability and force uniformity under the alternating action of wind suction and wind pressure.

[0033] Further, the top of the precast pile 9 arranged at the end is provided with a pile top beam 8, and the pile top beam 8 is provided with two pile top columns 7 with different heights, and the two pile top columns 7 are respectively connected to two end points of the triangular support 6. Referring to Figure 4 The end frame structure diagram shows that the asymmetric arrangement can optimize the included angle between the long-direction installation cable 1 and the cable-stayed member 11 by adjusting the height difference between the two columns.

[0034] By adjusting the column height, the cable system tension angle can be controlled, and then the size and direction of the end horizontal thrust can be adjusted, thereby reducing the adverse effects on the foundation, and the method is especially suitable for sites with poor geological conditions or sites that do not allow large excavation. At the same time, the pile top beam 8 integrates the two pile top columns 7, thereby enhancing the integrity and torsional resistance of the end node and being beneficial to balanced load transmission.

[0035] In an embodiment, the triangular support 6 is a triangular rigid frame structure, the top two end points of which are respectively connected to the long-direction installation cable 1 and one end of the cable-stayed member 11, and the other end of the cable-stayed member 11 extends downward and is connected to the precast pile 9. Referring to Figure 4 The end frame structure diagram shows that the triangular support 6 serves as a core load transmission node and bears the tension from the long-direction installation cable 1 and the reverse tension from the cable-stayed member 11.

[0036] The triangular rigid frame structure is made of high-strength steel and is integrally welded into shape, and has good bending resistance, shear resistance and tensile resistance. The rigid connection characteristics ensure the continuity and reliability of the force flow transmission, and avoid loss of cable force or structural instability due to excessive node deformation. In addition, the structure form is convenient for standardized processing in the factory and rapid installation on site, thereby improving the construction efficiency.

[0037] The two ends of the cable-stayed member 11 are connected to the triangular support 6 and the precast pile 9 in a hinged manner. Referring to Figure 4 The end frame structure diagram shows that one end of the cable-stayed member 11 is connected to the end point of the triangular support 6, and the other end is connected to the side or the top reserved ear plate of the lower precast pile 9.

[0038] The hinged connection can release the rotational constraint, avoid additional bending moment caused by foundation settlement or temperature deformation, and reduce the risk of stress concentration at the node. At the same time, the hinged structure simplifies the on-site installation process and improves the controllability of construction precision. In actual engineering, high-strength bolt hinging or pin shaft connection forms can be selected according to the stress requirements, so as to ensure safety and reliability while taking into account economy.

[0039] Further, the long-direction installation cable 1 is provided with a node at each installation position corresponding to a photovoltaic module, and the load is transmitted to the cable body through a virtual rod. Referring to Figure 3The long-span structure schematic diagram is shown. In the structural modeling analysis process, a calculation node is arranged at every certain distance (for example, 1.6-2.0 meters) along the long direction installation cable 1 to simulate the actual installation interval of the photovoltaic module.

[0040] In the finite element model, a virtual rod (i.e. a virtual rod only transmitting axial force and not participating in actual construction) is arranged between the nodes to guide the dead load, wind load and the like of the photovoltaic module to the long direction installation cable 1 in one direction. The modeling method conforms to the actual stress condition and can accurately reflect the influence of the local load on the cable body, and is particularly helpful for evaluating the deformation response and stress distribution of the long direction cable under the local concentrated load.

[0041] In the optional implementation, the sag between the upper stable cable 2 and the lower bearing cable 3 is determined in advance through the structural analysis model, and the sag of the lower bearing cable 3 in the short span direction is adjustable. The sag mainly depends on the elevation difference of the two end supports and the height of the connection point of the mid-span support rod, and the spatial form is basically fixed after the structure is installed.

[0042] In the design stage, the structural analysis model can be determined by parameterized modeling and iterative analysis, considering the load conditions (dead load, wind pressure, wind suction, snow load and temperature change), deformation limit requirement and component stress ratio requirement, and the initial prestress level of each cable is optimized and determined. In addition, by adjusting the sag of the lower bearing cable 3 (i.e. by adjusting the height of the mid-span support rod or the elevation difference of the end support), the horizontal thrust on the end pile body can be adjusted and controlled, and the collaborative stress optimization of the upper structure and the lower foundation can be realized.

[0043] In summary, the large-span three-dimensional cable net system provided by the application realizes the high unification of structural safety, economy and construction convenience through modular design, efficient force transmission path and parameterized regulation mechanism. The above various optional implementation modes can be flexibly combined and applied according to the specific engineering requirements, and are suitable for photovoltaic support construction requirements under different span, terrain and climate conditions, and have wide application prospect and technical popularization value.

[0044] To construct the above system, the application provides a construction method of a large-span three-dimensional cable net system, as shown in Figure 6 The method comprises the following steps: S610, determining the span of the short span direction and the long span direction according to the actual site conditions.

[0045] This step is mainly to set the initial parameters of the overall layout of the large-span cable net system. Among them, the short-span direction refers to the direction in which the structure forms a basic force unit in a local range, which is the transverse span direction of the double-layer cable truss; the long-span direction refers to the large-span direction of the photovoltaic support extending in the longitudinal direction, which is the direction of the main span of the installation cable. The actual site conditions include topographic features, wind pressure and wind suction load distribution, snow load size, temperature variation range, geological survey data, and project requirements for land use, etc. Engineering boundary conditions.

[0046] In specific implementation, first, the meteorological data and geological survey report data of the project site are obtained, and according to the arrangement requirements of the photovoltaic array and the electrical layout requirements, the appropriate structural span configuration is determined. The span in the short-span direction is generally determined according to the reasonable economic span of the double-layer cable truss to ensure that it has sufficient vertical stiffness to resist gravity and wind suction; the span in the long-span direction is determined according to the distance between topographic obstacles (such as gullies, water bodies) and the position where the anchor point can be arranged. By reasonably dividing the short span and the long span, the entire system can not only meet the large-span spanning capability, but also realize efficient transmission of structural stress.

[0047] S620, a structure analysis model is established according to the span, and a long-direction installation cable extending along the long-span direction, a plurality of short-span double-layer cable trusses arranged at intervals along the long-span direction, and a prefabricated pile located at the end and the middle are arranged in the structure analysis model; wherein each short-span double-layer cable truss includes an upper stabilizing cable and a lower pressure-bearing cable, the upper stabilizing cable is arranged in an upper convex arc shape, the lower pressure-bearing cable is arranged in a lower concave arc shape, and the two are connected by a vertically arranged steel strut to form a planar cable truss structure; the long-direction installation cable transversely spans a plurality of short-span double-layer cable trusses and is connected with the short-span double-layer cable truss at the top node and the bottom node of the inner triangle of the span, and the position of each short-span double-layer cable truss in the long-span direction corresponds to the support point of the long-direction installation cable.

[0048] The above structure analysis model is a numerical calculation model established based on the finite element theory, which is used to simulate the static and dynamic responses of the cable net system. In modeling, the components such as cables, struts, connectors and pile foundations in the actual structure are abstracted into corresponding unit types such as cable elements, beam elements, bar elements, etc., and are given material properties and boundary constraint conditions.

[0049] In the structural analysis model, a plurality of long-directional installation cables arranged in parallel are provided along the long span direction for directly bearing the photovoltaic components and transmitting their loads to the support system. A plurality of short-span double-layer cable trusses are arranged equidistantly or as needed along the long span direction to form a spatial grid-shaped support framework. Each short-span double-layer cable truss is composed of an upper-layer stabilizing cable and a lower-layer pressure-bearing cable: the upper-layer stabilizing cable is in the form of an upwardly arched arc, mainly used for resisting the pulling effect caused by upward wind suction; the lower-layer pressure-bearing cable is in the form of a downwardly hanging curve, mainly used for bearing the vertical pressure trend of the photovoltaic components under the action of self weight and wind pressure. The two layers of cables are connected by a vertically arranged steel strut, which can form a triangular or trapezoidal support configuration (such as an in-span triangular strut) in the span, thereby enhancing the overall stability and cooperative work performance of the cable truss in the plane.

[0050] The long-directional installation cables span all the short-span double-layer cable trusses in space and are physically connected at the in-span triangular strut connection nodes at the top of each cable truss. At this time, the short-span double-layer cable trusses act as intermediate support points of the long-directional installation cables, effectively reducing their deflection deformation under the action of vertical loads. In addition, precast piles are provided at both ends and intermediate positions of the system as the main vertical and horizontal bearing members of the entire cable net system, providing the necessary anchoring counterforce.

[0051] The authenticity of the load transmission path also needs to be considered in the modeling process. For example, virtual connection bars (virtual bars) are provided between the long-directional installation cables according to the actual arrangement position of the photovoltaic components to unidirectionally transmit the component loads to the long-directional cables; at the same time, the rotational degrees of freedom are released at the key nodes to accurately simulate the connection characteristics between the cables, struts and piles. The entire model can be spliced into multiple basic units for overall analysis according to the actual engineering situation, and it is recommended to include at least two complete structural units to reflect the continuity effect.

[0052] S630, according to the initial stress and internal force of the upper-layer stabilizing cable, the lower-layer pressure-bearing cable and the long-directional installation cable, determining the cross-sectional form and size of the cable body and the steel member connecting the cable body and constituting the overall force system.

[0053] The initial stress refers to the tension force pre-applied inside the cable body before the action of external loads, used to form a pre-tightened state of the structure, improve the overall stiffness and control the subsequent deformation. The internal force refers to the axial force, bending moment or shear force generated by each component under the action of single or combined loads such as dead load, wind pressure, wind suction, snow load and temperature change. The steel member connecting the cable body and constituting the overall force system can include steel struts, pile top columns, triangular supports and cable-stayed members.

[0054] In the implementation process, first of all, based on the structural analysis results obtained in S620, the stress state of the upper stable cable, the lower bearing cable and the long direction installation cable under different working conditions is extracted, including the maximum tension, the minimum tension and the stress fluctuation range. According to the mechanical properties of the selected cable material (such as tensile strength and elastic modulus), the cross-sectional parameters of each type of cable body, such as diameter, strand number and sheath form, are preliminarily selected, so that it still meets the specified stress ratio limit value (i.e. the actual stress does not exceed the proportional requirement of the allowable stress) under the most unfavorable load combination.

[0055] For steel members connected with the cable body and jointly constituting the overall force system, such as the in-span triangular brace, the in-span intermediate connecting rod, the pile top column, the triangular support, etc., appropriate cross-sectional forms (such as circular pipes, H-shaped steel, angle steel, etc.) and geometric sizes also need to be selected according to their internal force response in the model (mainly axial force and bending moment). The design of these components should ensure that they do not yield, destabilize or fatigue under complex stress conditions.

[0056] The initial stress setting of the above-mentioned cable body is coupled with its final cross-sectional size. If the selected cross-section under the current initial stress condition cannot meet the stress ratio requirement, the initial stress size needs to be adjusted, and the structure deformation is recalculated to see if it still meets the limit value. In practical application, this process may need to be iterated and optimized several times until both the deformation control and the component strength double objectives are met.

[0057] S640, according to the geological exploration information and the end node force data, adjusting the sag height of the lower bearing cable and the cross-sectional parameters of the cable-stayed member, determining the length and cross-sectional size of the precast pile to construct the large-span three-dimensional cable net system.

[0058] The above-mentioned geological exploration information includes soil distribution, groundwater level, soil physical and mechanical parameters (such as friction angle, cohesion, bearing capacity characteristic value), etc. The end node force data refers to the axial tension, horizontal thrust, bending moment and shear force at the top of the pile extracted from the structural analysis model.

[0059] In specific implementation, first of all, the stress mechanism at the end of the short span direction is analyzed. Since the lower bearing cable is arranged in a concave arc shape, a large horizontal tension will be generated at its two ends, which is transmitted to the precast pile through the pile top structure. By adjusting the sag height of the lower bearing cable, i.e. changing its vertical span ratio, the size of the horizontal component force can be adjusted: increasing the sag degree can reduce the horizontal force, but it will increase the risk of vertical deformation; reducing the sag will increase the horizontal force and require higher uplift and anti-sliding requirements for the pile foundation.

[0060] Meanwhile, the cable-stayed member is arranged between the two piles at the end portion to form a cable-stayed system in a diagonal direction, which is used to balance the partial bending moment and the horizontal shear force. By adjusting the cross-sectional parameters (such as diameter, wall thickness, material grade, etc.) of the cable-stayed member, the rigidity and load-carrying capacity thereof can be controlled, thereby affecting the bending moment distribution on the pile body. Preferably, the cable-stayed member can be made of high-strength steel strand or steel bar, and the connection mode thereof is preferably hinged or semi-rigid, so as to adapt to the deformation coordination requirement.

[0061] After comprehensively considering the above factors, in combination with the side resistance and end resistance characteristics of each soil layer in the geological exploration data, the pile foundation bearing capacity is calculated. The calculation contents include but are not limited to: compressive bearing capacity, uplift bearing capacity (considering the uplift working condition), bending bearing capacity (resisting bending moment), crack bearing capacity (for concrete piles), and horizontal bearing capacity (resisting wind-induced horizontal thrust). According to the calculation results, the total length, cross-sectional shape (such as circular, square), size (such as diameter or side length) and reinforcement scheme (if applicable) of the precast pile are finally determined to ensure its safety and reliability throughout its life cycle.

[0062] In summary, the complete construction process of the large-span three-dimensional cable net system is completed, and the new type of flexible photovoltaic support system with high efficiency, low material consumption and strong adaptability is realized.

[0063] Further, the embodiment of the present application provides a specific construction method of a large-span three-dimensional cable net system, which is applied to the large-span three-dimensional cable net system of the foregoing embodiment. The large-span three-dimensional cable net system includes long-span cables, short-span upper-layer cables and lower-layer cables, and end and middle piles. The short-span upper-layer cables and the lower-layer cables are connected through intra-span triangular braces and intra-span intermediate connecting rods. The long-span cables are connected with two top end points of the intra-span triangular braces. The end and middle piles are connected with the triangular braces through pile top columns. Two end points of the triangular braces are connected with the long-span cables. The two middle piles are connected through X-shaped supports. The two piles in the end pile are connected through a top beam. Two pile top columns with different heights are arranged on the beam and connected with the long-span cables.

[0064] Referring to Figure 7 The design method of the large-span three-dimensional cable net system specifically includes the following steps: S710, the span and load working condition of the short-span and long-span directions are determined according to the actual site condition.

[0065] S720, the stress conditions of each component of the large-span three-dimensional cable net system are determined by modeling and analyzing the structure according to the span and load working condition.

[0066] In the analysis model, virtual rods are arranged between the long-span cables according to the actual position of the photovoltaic components. The photovoltaic component load is unidirectionally guided to the long-span cables. The long-span cables are provided with nodes at each virtual rod position and the rotational freedom is released.

[0067] It should be noted that two short-span double-layer cable trusses, short-span and medium-span are a unit, and the number of units can be arbitrarily spliced according to the actual site conditions, and two units can be analyzed during modeling and analysis. The nodes of the in-span triangular brace are rigidly connected, and the ends of the in-span intermediate connecting rod are hingedly connected. The ends of the cable-stayed cable can be hingedly connected or rigidly connected. The two end points of the top of the triangular support can be hingedly connected or rigidly connected.

[0068] S730, according to the stress state of each component, adjust the initial stress of the upper cable, the lower cable and the long-span cable, so that the structure meets the deformation limit value requirement under the single working condition and the combined working condition of dead load, wind pressure, wind suction, snow load and temperature load.

[0069] It should be noted that the deformation limit value requirement includes the deformation under single working condition and the deformation under combined working condition, and the local deformation should also be less than the deformation limit value requirement of the photovoltaic module.

[0070] S740, according to the initial stress of the cable and the internal force of other steel components, determine the cross-sectional form and cross-sectional size of the cable and other steel components, so that the components meet the stress ratio limit value requirement.

[0071] It should be noted that the initial stress of the cable and the internal force under the stress state are related to the material and cross-sectional size of the cable. After the initial stress determined in step S730 meets the deformation limit value requirement, if the stress ratio requirement cannot be met in step S740, the cross section of the cable should be adjusted, and the initial stress size should be returned to step S730 for adjustment, and the deformation size should be calculated.

[0072] S750, according to the geology survey data and the stress state of the end nodes, adjust the sag height of the lower cable of the short-span and the cross-sectional form and cross-sectional size of the cable-stayed component, determine the length and cross-sectional size of the precast pile, so that the precast pile meets the requirements of compression bearing capacity, uplift bearing capacity, bending bearing capacity, crack bearing capacity and horizontal bearing capacity.

[0073] It should be noted that in the short-span direction, the two piles connected at the top and bottom of the cable-stayed component are balanced by the cable-stayed component. The horizontal force on the two end piles can be adjusted by adjusting the sag height of the lower cable of the short-span, and the bending moment on the two end piles can be adjusted by adjusting the cross-sectional form and cross-sectional size of the cable-stayed component. In summary, the double-layer cable truss arranged in short spans has superior load-bearing performance, can effectively bear gravity load and wind suction load, can provide reliable support for the long-direction installation cable, makes the force transmission path of the three-dimensional cable net clear, the structure efficient, and the overall deformation well controlled, and is conducive to ensuring the power generation efficiency of the photovoltaic panel. The system fully utilizes the tensile performance of the cable material and the load-bearing advantage of the steel compression strut, significantly reduces the amount of steel compared to the traditional photovoltaic support, and thus reduces the construction cost. In addition to the cable system arrangement, only steel components are used at key positions such as the pile top support and the cable truss strut, and the component size is optimized through standardized design, so that the length and weight of the largest component are reasonably controlled, which is conducive to standardized processing in the factory and facilitates on-site installation. In addition, the system has good adaptability and expandability, and can flexibly adjust the number of units and be spliced and combined according to the site conditions and span requirements in actual engineering, realize the structural arrangement of various spans and forms, and have practicability and economy.

[0074] Further, the present application also provides a flexible photovoltaic support comprising the large-span three-dimensional cable net system of any one of the preceding embodiments, which is used as a support structure for installing photovoltaic components.

[0075] In practical application, the flexible photovoltaic support uses a spatial cable net as the main load-bearing system to replace the traditional rigid beam-column type support structure. A plurality of installation cables arranged in parallel are arranged in the long-span direction, which are used to directly bear the photovoltaic components and realize the fixation and positioning of the components through clamps or connecting pieces. The installation cables span a large distance in the longitudinal direction to form a continuous panel area, which meets the arrangement requirements of large-scale photovoltaic arrays.

[0076] In order to control the deformation of the installation cable under the action of vertical load, short-span double-layer cable trusses are arranged in the long-span direction at intervals as intermediate support structures of the installation cable. Each short-span double-layer cable truss is composed of an upper stable cable and a lower pressure-bearing cable: the upper stable cable is in an upward convex arc shape and is mainly used to resist the upward tension caused by wind suction load; the lower pressure-bearing cable is in a downward concave arc shape and bears the vertical pressure trend of the photovoltaic components under the action of self weight and wind pressure. The two layers of cables are connected by vertical steel struts to form a triangular or trapezoidal configuration in the span, which enhances the in-plane stiffness and realizes cooperative force bearing.

[0077] The installation cable horizontally spans a plurality of short-span double-layer cable trusses in space and is connected to each cable truss at the node position at the top of the cable truss. At this time, the short-span cable truss not only bears its own in-plane load, but also acts as an elastic support for the long-direction installation cable, effectively reducing its calculated span and deflection, thereby ensuring the flatness and structural safety of the photovoltaic components during operation.

[0078] The dead load, wind load, snow load and the like of the photovoltaic module are firstly transmitted to the short-span double-layer cable truss through the installation cable, and then transmitted to the precast piles at the end and the middle through the pile top column, and finally dispersed into the ground soil by the pile foundation. The whole system forms a self-balancing spatial force mechanism with high structural efficiency and stability.

[0079] Since the main force member is a high-strength steel cable, the tensile performance of the material is fully utilized, and the overall steel consumption is significantly lower than that of the traditional steel structure support, which has good economy. At the same time, except for the pile top connection part, the support rod and the local reinforcing member, the rest of the structural units are flexible cable bodies, which are small in size, light in weight, easy to prefabricate in the factory, transport and install on site, and suitable for areas with poor transportation or sensitive ecology such as Gobi, desert, beach and water area.

[0080] In summary, the flexible photovoltaic support realizes a new support form with large span, low material consumption and high adaptability by introducing a large-span three-dimensional cable net system. Not only does it solve the problems of insufficient rigidity, weak wind resistance and low material utilization of traditional flexible supports, but also provides a feasible technical path for the construction of large-scale photovoltaic power stations in complex terrain conditions.

[0081] In the description of the present application, it should be further pointed out that unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection" and "connection" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0082] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A large-span three-dimensional cable net system, characterized in that, It includes a long installation cable extending along the long span direction, multiple short-span double-layer cable trusses spaced apart along the long span direction, and precast piles located at the ends and the middle. The short-span double-layer cable truss is arranged along the short-span direction and spans the entire short-span. Each short-span double-layer cable truss includes an upper stabilizing cable and a lower bearing cable. The upper stabilizing cable is arranged in an upward convex arc shape, and the lower bearing cable is arranged in a downward concave arc shape. The upper stabilizing cable and the lower bearing cable are connected by vertically arranged steel struts to form a planar cable truss structure. The position of each of the short-span double-layer cable trusses in the long span direction corresponds to the support point of the long-direction installation cable. The long-direction installation cable laterally spans multiple short-span double-layer cable trusses and connects to the short-span double-layer cable trusses at the top and bottom nodes of the triangular brace within the span. The precast piles at the ends are connected to the triangular brackets via pile top columns. The two ends of the triangular brackets are respectively connected to the longitudinal installation cable and the inclined tie member. The adjacent precast piles in the middle are connected by cross-set inclined supports.

2. The large-span three-dimensional cable net system according to claim 1, characterized in that, The short-span double-layer cable truss also includes an inner-span intermediate connecting rod, the two ends of which are connected to the upper-layer stabilizing cable and the lower-layer bearing cable, respectively, and are arranged on both sides of the steel strut in a vertical direction.

3. The large-span three-dimensional cable net system according to claim 2, characterized in that, The inner span triangular brace consists of three rods forming an inverted triangle structure. The top two nodes of the inner span triangular brace are connected to the longitudinal installation cable, the bottom node is connected to the lower bearing cable, and the top of the extended rod of the triangular brace is connected to the upper stabilizing cable.

4. The large-span three-dimensional cable net system according to claim 3, characterized in that, The top of the precast pile at the end is provided with a pile top beam, and two pile top columns of different heights are provided on the pile top beam. The two pile top columns are respectively connected to the two ends of the triangular bracket.

5. The large-span three-dimensional cable net system according to claim 1 or 4, characterized in that, The triangular bracket is a triangular rigid frame structure, with its two top ends connected to one end of the longitudinal installation cable and one end of the inclined tie member, respectively. The other end of the inclined tie member extends downward and connects to the precast pile.

6. The large-span three-dimensional cable net system according to claim 5, characterized in that, The two ends of the cable-stayed member are connected to the triangular bracket and the precast pile by hinges.

7. The large-span three-dimensional cable net system according to claim 1, characterized in that, The longitudinal installation cable has nodes at the installation positions corresponding to each photovoltaic module, and the load is transferred to the cable body through virtual rods.

8. The large-span three-dimensional cable net system according to claim 1, characterized in that, The sag between the upper stabilizing cable and the lower bearing cable is predetermined by the structural analysis model, and the sag height of the lower bearing cable in the short span direction is adjustable.

9. A method for constructing a large-span three-dimensional cable net system, characterized in that, include: The spans in the short and long span directions are determined based on the actual site conditions. A structural analysis model is established based on the span. In this model, a long-span installation cable extending along the long span direction, multiple short-span double-layer cable trusses spaced apart along the long span direction, and precast piles located at the ends and middle are arranged. Each short-span double-layer cable truss includes an upper stabilizing cable and a lower bearing cable. The upper stabilizing cable is arranged in an upwardly convex arc shape, and the lower bearing cable is arranged in a downwardly concave arc shape. The two are connected by vertically arranged steel struts to form a planar cable truss structure. The long-span installation cable laterally spans multiple short-span double-layer cable trusses and connects to the short-span double-layer cable trusses at the top and bottom nodes of the triangular braces within the span. The position of each short-span double-layer cable truss in the long span direction corresponds to the support point of the long-span installation cable. Based on the initial stress and internal force of the upper stabilizing cable, the lower bearing cable, and the longitudinal installation cable, determine the cross-sectional shape and dimensions of the cable body and the steel components that connect the cable body and form the overall force-bearing system. Based on geological survey information and end node stress data, the sag height of the lower bearing cable and the cross-sectional parameters of the cable-stayed member are adjusted to determine the length and cross-sectional specifications of the precast piles in order to construct a large-span three-dimensional cable net system.

10. A flexible photovoltaic support structure, characterized in that, The system includes the large-span three-dimensional cable net system as described in any one of claims 1 to 8, wherein the large-span three-dimensional cable net system serves as a support structure for installing photovoltaic modules.

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