Truss type widening structure of roadbed and design method

Abstract

The invention relates to the technical field of roadbed engineering, in particular to a truss type widening structure of a roadbed and a design method.The widening structure comprises a supporting truss and a replacement foundation, the supporting truss is arranged on one side of the existing roadbed and matched with the existing roadbed, and the replacement foundation is arranged below the supporting truss and matched with the existing roadbed. The replacement filling foundation is used for bearing the supporting truss so as to avoid settlement of the supporting truss, and the supporting truss can bear the upper load so as to avoid structural deformation. The supporting truss of the rigid frame structure is adopted as a main body frame of the widening structure, sufficient rigidity is achieved to resist upper loads, structural deformation can be avoided, and then settlement caused by insufficient rigidity of the structure is avoided; the replacement filling foundation made of the light replacement filling materials is better in bearing performance for the supporting truss and loads above the supporting truss, and the situation that the supporting truss and the loads above the supporting truss compress the replacement filling foundation to cause settlement can be avoided to the maximum extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of roadbed engineering, and in particular to a truss type widening structure of roadbed and a design method thereof. BACKGROUND

[0002] At present, with the wide implementation of new construction or reconstruction and expansion projects of railways and highways, a large number of existing railway and highway roadbed widening projects will inevitably be faced. Under the combined action of the widening filling body and the track and vehicle load, the existing roadbed may produce additional vertical uneven settlement and lateral deformation. The existing widening roadbed often uses similar earthwork filling body to fill, and the earthwork has large self-weight and poor stiffness. On the one hand, the widening filling body will press down the original foundation to cause uneven settlement under the action of self-weight, and on the other hand, the widening filling body itself will also produce obvious uneven settlement due to insufficient stiffness. However, the control requirements of high-speed railway ballastless track on settlement deformation are very strict, and the conventional widening technology is difficult to meet the control requirements of the settlement and deformation of the existing roadbed and the widening roadbed. Therefore, it is necessary to further improve the existing widening structure to overcome the technical problems of uneven settlement. SUMMARY

[0003] The present application aims to overcome the technical problems of the existing earthwork widening filling body, which has large self-weight to press down the original foundation and poor stiffness to easily produce structural deformation and further cause uneven settlement, and provides a truss type widening structure of roadbed and a design method thereof.

[0004] In a first aspect, the present application provides a truss type widening structure of roadbed, which comprises a support truss and a replacement foundation. The support truss is arranged on one side of an existing roadbed and is adapted to the existing roadbed. The replacement foundation is arranged below the support truss and is used to bear the support truss to avoid settlement of the support truss. The support truss can bear the upper load to avoid structural deformation.

[0005] The present application adopts a support truss as the main frame of the widening structure, which can match the slope part of the existing roadbed, and is installed on one side of the existing roadbed to widen the roadbed. The support truss is a rigid frame structure with sufficient rigidity to resist the upper load, so that structural deformation and settlement due to insufficient rigidity of the structure itself can be avoided. The foundation under the support truss is a replacement foundation, that is, the original foundation is excavated and then filled with replacement materials. The replacement materials can be lightweight materials with a smaller specific gravity than the original foundation material before replacement and a larger rigidity than the original foundation material before replacement. In addition, the self-weight of the support truss is lighter than the existing earthwork filler, that is, the replacement foundation has better bearing performance for the support truss and the load thereon, and can maximize the compression of the replacement foundation and the settlement of the support truss and the load thereon.

[0006] Preferably, the support truss is provided with a diagonal brace.

[0007] Specifically, the cross section of the support truss can be designed as a structure similar to a parallelogram, and a diagonal brace structure is arranged at the diagonal position in the parallelogram of the cross section of the support truss, so as to enhance the rigidity, compression resistance and load resistance of the support truss as a whole, and avoid structural deformation of the support truss when subjected to an upper load (such as a road panel, a track on the road surface, a vehicle, etc.), so that the support truss is compressed. The diagonal brace structure can improve the overall mechanical properties of the support truss.

[0008] Preferably, a rigid bottom plate is arranged between the support truss and the replacement foundation.

[0009] Since the support truss is a hollow frame structure, the contact points between the bottom of the support truss and the replacement foundation will be concentrated on the edge frame body of the support truss, which may cause local compression of the replacement foundation and settlement. Therefore, a rigid bottom plate can be arranged between the support truss and the replacement foundation. The rigid bottom plate is a rigid structure, which covers the replacement foundation and makes the load of the support truss uniformly act on the replacement foundation, so that the replacement foundation is uniformly stressed and settlement due to local compression can be avoided.

[0010] Preferably, the width of the rigid bottom plate, the width of the replacement foundation and the width of the bottom of the support truss are consistent.

[0011] Here, the width of the rigid bottom plate, the width of the replaced foundation, and the width of the bottom of the support truss are all the dimensions along the width direction of the existing roadbed, that is, the dimensions on the cross section of the existing roadbed, and the widths of the above three are kept the same, so that the support truss and the rigid bottom plate can completely cover the upper surface of the replaced foundation, the rigid bottom plate, the support truss, and the upper load can be completely and uniformly distributed on the replaced foundation, the stress area of the upper surface of the replaced foundation can be maximally utilized to disperse the load and reduce the pressure on the replaced foundation, and further, the settlement can be avoided as much as possible.

[0012] Preferably, the top of the support truss is provided with a panel assembly, and the height of the upper surface of the panel assembly is consistent with the height of the upper surface of the existing roadbed.

[0013] The installation of the panel assembly on the upper part of the support truss can constitute a pavement structure, which facilitates the installation of a track and other pavement facilities above the pavement for the passage of vehicles and personnel, and makes the upper surface of the panel assembly flush with the upper surface of the existing roadbed, so that the widened structure and the existing roadbed form an integrated widened pavement structure.

[0014] Preferably, the panel assembly comprises a first panel and a second panel arranged in a stack, the lower surface of the first panel is provided with a plurality of first stiffening ribs along the width direction of the roadbed, and the upper surface of the second panel is provided with a plurality of second stiffening ribs along the width direction of the roadbed.

[0015] The double-layer panel structure arranged in a stack and the plurality of stiffening ribs arranged on the panel can significantly improve the rigidity and compression resistance of the panel structure, the stiffening ribs arranged on the lower surface of the upper panel and the upper surface of the lower panel can form flat mounting surfaces on the upper and lower surfaces of the panel assembly, facilitating the installation of facilities above the pavement and the connection with the support truss below; the stiffening ribs can be arranged along the length direction of the roadbed, that is, the length direction of the stiffening ribs is consistent with the length direction of the roadbed, and the cross section of the stiffening rib can be formed into a structure similar to a trapezoid, which has sufficient compression resistance and deformation resistance, can improve the rigidity of the panel, and avoid the deformation of the panel caused by the upper load of the pavement, thereby preventing the pavement from settling.

[0016] Preferably, the support truss comprises a plurality of support trusses, the plurality of support trusses are sequentially spliced along the length direction of the roadbed, the plurality of support trusses are provided with a counterweight and a sliding rail, the sliding rail is arranged along the width direction of the roadbed, and the counterweight can slide along the sliding rail to adjust the center of gravity of the support truss.

[0017] Since the length of the wide roadbed needs to be long, multiple support trusses need to be spliced in sequence in the length direction to form a wide structure, and counterweight blocks and sliding rails are arranged in each support truss, the sliding rails can be arranged in the width direction of the roadbed, that is, the length direction of the sliding rails is consistent with the width direction of the roadbed, by adjusting the position of the counterweight block on the sliding rail, the center of gravity of the support truss is adjusted, specifically, the load on the support truss can be adjusted according to the load on the support truss, if the load on the support truss is far away from the existing roadbed, the position of the counterweight block can be adjusted to be close to the existing roadbed, the center of gravity of the support truss can be adjusted to be close to the middle position of the support truss, and the occurrence of uneven settlement can be further avoided; similarly, if the load on the support truss is close to the existing roadbed, the position of the counterweight block can be adjusted to be far away from the existing roadbed, and the center of gravity of the support truss can also be adjusted to be close to the middle position of the support truss, and the same technical effect of avoiding uneven settlement can be achieved.

[0018] Preferably, the filler in the replacement foundation comprises lightweight concrete.

[0019] The filler of the replacement foundation can specifically adopt lightweight concrete, the specific weight of the lightweight concrete is less than the specific weight of the original foundation material (such as earthwork) before the replacement of the replacement foundation, and the stiffness of the lightweight concrete is greater than the stiffness of the original foundation material (such as earthwork) before the replacement of the replacement foundation, which can improve the bearing performance of the replacement foundation for the support truss and the load thereon, and can maximize the avoidance of the compression of the replacement foundation by the support truss and the load thereon.

[0020] In a second aspect, the present application provides a design method of a truss type wide structure of a roadbed, which is used for designing and checking the truss type wide structure of the roadbed as described above, the support truss is provided with a counterweight block and a sliding rail, a rigid bottom plate is arranged between the support truss and the replacement foundation, a top of the support truss is provided with a panel assembly, and a track and a vehicle are arranged on the panel assembly; the design method comprises zero additional load checking, and the zero additional load checking comprises: S1: respectively calculating the load G1 of the sliding rail, the load G2 of the counterweight block, the load G3 of the original foundation soil of the replacement foundation before replacement, the load G4 of the rigid bottom plate and the load G5 of the replacement foundation per meter along the length direction of the roadbed: ; ; ; ; ; In the above formulas, F1 is the load of the sliding rail, F2 is the load of the counterweight block, D is the distance between the center of gravity of the support truss and the center of gravity of the counterweight block, and G is the specific weight of the counterweight block.1~2 The distance between two adjacent sets of slide rails and counterweights along the length of the roadbed is γ3, where γ3 is the unit weight of the original foundation soil, γ4 is the unit weight of the rigid base plate, γ5 is the unit weight of the replacement foundation, S3 is the area of ​​the original foundation soil in the cross-sectional direction of the roadbed, S4 is the area of ​​the rigid base plate in the cross-sectional direction of the roadbed, and S5 is the area of ​​the replacement foundation in the cross-sectional direction of the roadbed. S2: Calculate the total load G of the sidewall structure, track, and vehicle load per meter along the length of the roadbed: G = G1 + G2 + G4 + G5 + G6 + G7 + G8; Wherein: G6 is the load of the vehicle per linear meter along the length of the roadbed, G7 is the load of the track per linear meter along the length of the roadbed, and G8 is the load of the supporting truss per linear meter along the length of the roadbed. S3: Determine the difference between G and G3. If G≤G3, then the baffle structure has no settlement.

[0021] Preferably, the calculation also includes a total load eccentricity check and a minimum eccentricity check for the most unfavorable load. The total load eccentricity check must satisfy the following formula: G7L7+G8L8=G2L2; The most unfavorable load small eccentricity check must satisfy the following formula: ; Wherein: L7 is the horizontal distance between the load of the panel assembly and the track and the centerline of the rigid base plate; L8 is the horizontal distance between the support truss and the centerline of the rigid base plate; L2 is the horizontal distance between the counterweight and the centerline of the rigid base plate; L6 is the horizontal distance between the load of the vehicle and the centerline of the rigid base plate; and B4 is the width of the rigid base plate.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present application provides a kind of truss type widening structure of subgrade and design method, by adopting support truss as the main frame of widening structure, its shape can match with the slope part of existing subgrade, install in the side of existing subgrade can widen subgrade, support truss is rigid frame structure, with enough rigidity to resist upper load, can avoid structural deformation, and then avoid settlement due to insufficient rigidity of structure itself;The foundation under support truss adopts replacement foundation, that is, the original foundation is excavated, and then filled with replacement material to replace, the replacement material used can be light material, its specific gravity is less than the specific gravity of the original foundation material before replacement of replacement foundation, and the rigidity is greater than the rigidity of the original foundation material before replacement of replacement foundation, and the self weight of support truss is lighter than the existing earthwork filler, that is, the bearing capacity of replacement foundation for support truss and its upper load is better, can avoid the compression of replacement foundation caused by support truss and its upper load to the greatest extent. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the cross-sectional schematic diagram of the truss type widening structure of subgrade and existing subgrade of the present application.

[0024] Figure 2 It is the overhead perspective schematic diagram of the truss type widening structure of subgrade and existing subgrade of the present application.

[0025] Markings in the figure: 1, existing subgrade, 2, support truss, 21, diagonal brace, 22, counterweight, 23, slide rail, 3, replacement foundation, 4, rigid bottom plate, 5, panel assembly, 51, first panel, 52, second panel, 53, first stiffener, 54, second stiffener, 6, track, 7, vehicle. DETAILED DESCRIPTION

[0026] The present application will be further described in conjunction with specific embodiments. However, it should not be understood as limiting the scope of the above-mentioned subject matter of the present application to the following embodiments, and any technology realized based on the content of the present application falls within the scope of the present application.

[0027] In the description of the specific embodiments of the present application, the orientation or positional relationship terms such as "up", "down", "left", "right", "center", "inner", "outer" and the like appear without special indication, which are based on the orientation or positional relationship expressed in the drawings, or the orientation or positional relationship when the product / equipment / device of the present application is usually used. These orientation or positional relationship terms are only for the convenience of describing the present application scheme or simplifying the description in the specific embodiments, for the convenience of the technical personnel to quickly understand the scheme, and are not intended to indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship, therefore it cannot be understood as a limitation on the present application.

[0028] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or overhanging or parallel, but can be slightly inclined or have a deviation. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. Alternatively, it can be simplified to understand that the corresponding device / component / element is arranged in the direction of "horizontal", "vertical", "overhanging", "parallel" and the like, and can have an error / deviation of ±10% relative to the corresponding direction, more preferably an error / deviation of ±8% or less, more preferably an error / deviation of ±6% or less, more preferably an error / deviation of ±5% or less, and more preferably an error / deviation of ±4% or less. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the present application.

[0029] In addition, the terms "first", "second", "third" and the like in the terms are only used to distinguish the same or similar components for description, and should not be understood as emphasizing or implying the relative importance of the specific components.

[0030] In addition, in the description of the embodiments of the present application, "several", "a plurality of", "several" represent at least 2. It can be 2, 3, 4, 5, 6, 7, 8, 9, etc. Any case, it can even be more than 9 cases.

[0031] In addition, in the description of the technical solutions of the present application, unless otherwise specified / limited / limited, the terms "arrangement", "installation", "connection", "connection", "provided with", "laid", "arrangement" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, which can be welding, riveting, bolting, screwing and other commonly used connection means in the art. The connection can be mechanical connection, electrical connection or communication connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the communication between two elements.

[0032] Embodiment 1 The present embodiment provides a truss type widening structure of a roadbed.

[0033] Figure 1 The present embodiment provides a truss type widening structure of a roadbed. Figure 2 The present embodiment provides a truss type widening structure of a roadbed.

[0034] As Figures 1 to 2As shown in the middle, the truss type widening structure of the roadbed of the embodiment comprises a support truss 2 and a replacement foundation 3, the support truss 2 is arranged on one side of the existing roadbed 1 and is matched with the existing roadbed 1, the replacement foundation 3 is arranged below the support truss 2, the replacement foundation 3 is used to bear the support truss 2 to avoid the settlement of the support truss 2, and the support truss 2 can bear the upper load to avoid structural deformation.

[0035] The support truss 2 is used as the main frame of the widening structure, the shape of the support truss 2 can be matched with the slope part of the existing roadbed 1, the support truss 2 is arranged on one side of the existing roadbed 1 to widen the roadbed, the support truss 2 is a rigid frame structure and has sufficient rigidity to resist the upper load, so that structural deformation can be avoided, and settlement caused by insufficient rigidity of the structure itself can be avoided; the foundation below the support truss 2 is the replacement foundation 3, that is, the original foundation is excavated and then filled with replacement materials for replacement, the replacement materials can be lightweight materials, the gravity of the replacement materials is less than that of the original foundation materials before replacement of the replacement foundation 3, the rigidity of the replacement materials is greater than that of the original foundation materials before replacement of the replacement foundation 3, and the self-weight of the support truss 2 is lighter than that of the existing earthwork filler, that is, the replacement foundation 3 has better bearing performance for the support truss 2 and the load thereon, and can most effectively avoid settlement of the support truss 2 and the upper load thereof compressing the replacement foundation 3.

[0036] In the embodiment, the support truss 2 is provided with a diagonal brace 21; specifically, the cross section of the support truss 2 can be designed as a structure similar to a parallelogram, and the diagonal brace 21 structure is arranged at the diagonal position in the parallelogram of the cross section of the support truss 2, so as to enhance the rigidity, compression resistance and load resistance of the support truss 2 as a whole, and avoid structural deformation of the support truss 2 caused by compression when the support truss 2 is subjected to the upper load (such as the road panel, the track 6 on the road surface, the vehicle 7, etc.); the diagonal brace 21 structure can improve the mechanical properties of the support truss 2 as a whole; here, the diagonal brace 21 can be multiple, and the multiple diagonal braces 21 can be arranged in the support trusses 2 along the length direction of the roadbed.

[0037] In the embodiment, the rigid bottom plate 4 is arranged between the support truss 2 and the replacement foundation 3; since the support truss 2 is a hollow frame structure, the force points between the bottom of the support truss 2 and the replacement foundation 3 are concentrated on the side frame bodies of the support truss 2, and the replacement foundation 3 may be locally compressed and settled at the force points; therefore, the rigid bottom plate 4 is arranged between the support truss 2 and the replacement foundation 3, the rigid bottom plate 4 is a rigid structure as a whole, and the replacement foundation 3 is covered by the rigid bottom plate 4, so that the load of the support truss 2 is uniformly applied to the replacement foundation 3, the replacement foundation 3 is uniformly stressed, and local compression and settlement of the replacement foundation 3 can be avoided; here, the rigid bottom plate 4 can be a reinforced concrete bottom plate, and the reinforced concrete bottom plate can be installed on the construction site and cast in place by using reinforced concrete; of course, the rigid bottom plate 4 can also be made of other materials, as long as the material is rigid and can bear the upper load without deformation, and the present application does not make specific limitations in this regard.

[0038] Alternatively, the width of the rigid bottom plate 4, the width of the replacement foundation 3 and the width of the bottom of the support truss 2 are kept consistent; here, the width of the rigid bottom plate 4, the width of the replacement foundation 3 and the width of the bottom of the support truss 2 are all the dimensions along the width direction of the existing roadbed 1, that is, the dimensions on the cross section of the existing roadbed 1, and the widths of the above three (the rigid bottom plate 4, the replacement foundation 3 and the bottom of the support truss 2) are kept the same, so that the support truss 2 and the rigid bottom plate 4 can completely cover the upper surface of the replacement foundation 3, the rigid bottom plate 4, the support truss 2 and the upper load can be completely and uniformly distributed on the replacement foundation 3, the stress area of the upper surface of the replacement foundation 3 can be maximally utilized to disperse the load, the pressure on the replacement foundation 3 can be reduced, and settlement can be avoided as much as possible.

[0039] Similarly, a plurality of support trusses 2 can be arranged in sequence in the length direction of the roadbed, and the rigid bottom plate 4 is arranged below each support truss 2, and the rigid bottom plate 4 can also cover the replacement foundation 3 below in the length direction of the roadbed, so that the replacement foundation 3 is uniformly stressed at each position and uneven settlement is avoided.

[0040] In the embodiment, the top of the support truss 2 is provided with a panel assembly 5, and the height of the upper surface of the panel assembly 5 is consistent with the height of the upper surface of the existing roadbed 1; the panel assembly 5 is installed on the upper part of the support truss 2 to form a road surface structure, which facilitates the installation of a track 6 and other road surface facilities above the road surface to facilitate the passage of vehicles 7 and personnel, and the upper surface of the panel assembly 5 is flush with the upper surface of the existing roadbed 1, so that the widened structure and the existing roadbed 1 form an integrated widened road surface structure.

[0041] In the embodiment, the panel assembly 5 comprises a first panel 51 and a second panel 52 arranged in a stacked manner, the lower surface of the first panel 51 is provided with a plurality of first stiffening ribs 53 along the width direction of the roadbed, and the upper surface of the second panel 52 is provided with a plurality of second stiffening ribs 54 along the width direction of the roadbed; the double-layer panel structure arranged in a stacked manner and the plurality of stiffening ribs arranged on the panel can significantly improve the rigidity and compression resistance of the panel structure, the stiffening ribs arranged on the lower surface of the upper panel and the upper surface of the lower panel can form flat mounting surfaces on the upper and lower surfaces of the panel assembly 5, facilitating the installation of the facilities above the pavement and the connection with the support truss 2 below; the stiffening ribs can be arranged along the length direction of the roadbed, that is, the length direction of the stiffening ribs is consistent with the length direction of the roadbed, and the cross section of the stiffening ribs can be formed in a trapezoidal structure, which has sufficient compression resistance and deformation resistance and can improve the rigidity of the panel to avoid deformation of the panel caused by the load above the pavement, resulting in pavement settlement.

[0042] Specifically, the first panel 51 and the second panel 52 can both be orthotropic steel panels, the material of the first stiffening rib 53 and the material of the second stiffening rib 54 can both be steel, the first stiffening rib 53 can be fixed on the lower surface of the first panel 51 by welding, and the second stiffening rib 54 can be fixed on the upper surface of the second panel 52 by welding; of course, the first panel 51, the second panel 52, the first stiffening rib 53 and the second stiffening rib 54 can also be made of other rigid materials; and the specific structure of the panel assembly 5 can also be other forms of compression-resistant panels other than orthotropic steel panels, which are not limited in the present application.

[0043] In the embodiment, the wide structure comprises a plurality of support trusses 2, the plurality of support trusses 2 are sequentially spliced along the length direction of the roadbed, the plurality of support trusses 2 are provided with a counterweight 22 and a sliding rail 23, the sliding rail 23 is arranged along the width direction of the roadbed, and the counterweight 22 can slide along the sliding rail 23 to adjust the center of gravity of the support truss 2.

[0044] Since the length of the wide roadbed is usually long, a plurality of support trusses 2 need to be sequentially spliced in the length direction to form a wide structure, and the counterweight 22 and the slide rail 23 are arranged in each support truss 2. The slide rail 23 can be arranged in the width direction of the roadbed, that is, the length direction of the slide rail 23 is consistent with the width direction of the roadbed. By adjusting the position of the counterweight 22 on the slide rail 23, the center of gravity of the support truss 2 is adjusted. Specifically, the load on the support truss 2 can be adjusted. If the load on the support truss 2 is far away from the existing roadbed 1, the position of the counterweight 22 can be adjusted to be close to the existing roadbed 1, that is, the center of gravity of the support truss 2 can be adjusted to be close to the middle position of the support truss 2, so that the uneven settlement can be further avoided. Similarly, if the load on the support truss 2 is close to the existing roadbed 1, the position of the counterweight 22 can be adjusted to be far away from the existing roadbed 1, that is, the center of gravity of the support truss 2 can be adjusted to be close to the middle position of the support truss 2, so that the uneven settlement can be avoided.

[0045] Alternatively, the filler in the replacement foundation 3 includes lightweight concrete. The filler in the replacement foundation 3 can be lightweight concrete. The specific gravity of the lightweight concrete is less than that of the original foundation material (such as earthwork) before the replacement of the replacement foundation 3, and the stiffness of the lightweight concrete is greater than that of the original foundation material (such as earthwork) before the replacement of the replacement foundation 3. The load-bearing performance of the replacement foundation 3 for the support truss 2 and the load thereon can be improved, and the settlement of the replacement foundation 3 caused by the compression of the support truss 2 and the load thereon can be avoided to the greatest extent. Of course, other materials suitable for use as fillers in the replacement foundation 3 can also replace the lightweight concrete, and the present application does not make specific limitations in this regard.

[0046] Embodiment 2 The embodiment provides a design method of a truss type wide structure of a roadbed.

[0047] The design method of the truss type wide structure of the roadbed can be used to design and calculate the truss type wide structure of the roadbed in embodiment 1. The support truss 2 is provided with the counterweight 22 and the slide rail 23. The support truss 2 and the replacement foundation 3 are provided with the rigid bottom plate 4. The top of the support truss 2 is provided with the panel assembly 5. The panel assembly 5 is provided with the track 6 and the vehicle 7.

[0048] The design method includes zero additional load calculation, and the zero additional load calculation includes the following steps. S1: respectively calculating the load G1 of the slide rail 23, the load G2 of the counterweight 22, the load G3 of the original foundation soil of the replacement foundation 3 before replacement, the load G4 of the rigid bottom plate 4 and the load G5 of the replacement foundation 3 per meter along the length direction of the roadbed: ; ; ; ; ; In the above formulas: F1 is the load of the slide rail 23, F2 is the load of the counterweight block 22, D 1~2 is the distance between the two groups of slide rails 23 and counterweight blocks 22 adjacent in the length direction of the roadbed, γ3 is the unit weight of the original ground soil, γ4 is the unit weight of the rigid bottom plate 4, γ5 is the unit weight of the replacement foundation 3, S3 is the area of the ground soil in the cross-sectional direction of the roadbed, S4 is the area of the rigid bottom plate 4 in the cross-sectional direction of the roadbed, and S5 is the area of the replacement foundation 3 in the cross-sectional direction of the roadbed; S2: Calculate the total load G of the retaining structure and the loads of the track 6 and the vehicle 7 per meter in the length direction of the roadbed: G=G1+G2+G4+G5+G6+G7+G8; Wherein: G6 is the load of the vehicle 7 per meter in the length direction of the roadbed, G7 is the load of the track 6 per meter in the length direction of the roadbed, and G8 is the load of the support truss 2 per meter in the length direction of the roadbed.

[0049] The specific parameter values of G6, G7, and G8 can be obtained by estimation and measurement.

[0050] S3: Determine the size between G and G3, that is, the total load G of the retaining structure and the loads of the track 6 and the vehicle 7 per meter in the length direction of the roadbed should be less than or equal to the load G3 of the original ground soil, so as to ensure that the additional load is not greater than zero and avoid additional vertical uneven settlement and lateral deformation. Specifically, if G≤G3, the retaining structure will not settle; if G>G3, the retaining structure will settle, and then the above design parameters need to be adjusted and substituted into the above formulas for recalculation until G≤G3 is obtained.

[0051] In this embodiment, the design method further includes total load eccentricity checking and most unfavorable load small eccentricity checking. The total load eccentricity checking needs to satisfy the following formula: G7L7+G8L8=G2L2; The most unfavorable load small eccentricity checking needs to satisfy the following formula: ; Wherein: L7 is the horizontal distance between the load of the panel assembly 5 and the track 6 and the center line of the rigid bottom plate 4, L8 is the horizontal distance between the support truss 2 and the center line of the rigid bottom plate 4, L2 is the horizontal distance between the counterweight block 22 and the center line of the rigid bottom plate 4, L6 is the horizontal distance between the load of the vehicle 7 and the center line of the rigid bottom plate 4, and B4 is the width of the rigid bottom plate 4.

[0052] If the above two equations are not satisfied after substituting the parameters for total load eccentricity verification and minimum eccentricity verification under the most unfavorable load, the design parameters need to be readjusted until the above two equations are satisfied after substituting the parameters for verification.

[0053] It should be noted that during the calculation process, all the above parameters must be calculated using the same units; otherwise, calculation errors will occur. Specifically, for example, the units of G, G1, G2, G3, G4, G5, G6, G7, and G8 are kN / m, and the units of F1 and F2 are kN. 1~2 The unit for γ1 is m, and the units for γ3, γ4, and γ5 are kN / m. 3 The units for S3, S4, and S5 are meters. 2 The units for L2, L6, L7, L8, and B4 are in meters (m). If the units need to be changed for calculation, the units of all parameters must be changed synchronously to unify the dimensions.

[0054] In summary, this invention provides a truss-type widening structure for roadbeds and its design method. By using a supporting truss as the main frame of the widening structure, its shape can match the slope of the existing roadbed. Installed on one side of the existing roadbed, it can widen the roadbed. The supporting truss is a rigid frame structure with sufficient stiffness to resist the upper load, avoiding structural deformation and thus preventing settlement due to insufficient structural stiffness. The foundation below the supporting truss adopts a replacement foundation, which involves excavating the original foundation and replacing it with replacement material. The replacement material can be a lightweight material with a lower density than the original foundation material before replacement, and a higher stiffness than the original foundation material before replacement. Furthermore, the self-weight of the supporting truss is lighter than that of existing earth and rock fill. In other words, the replacement foundation has better bearing capacity for the supporting truss and the load above it, minimizing the risk of settlement caused by the supporting truss and the upper load compressing the replacement foundation.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A truss-type side-width structure for roadbed, characterized in that, It includes a support truss (2) and a replacement foundation (3). The support truss (2) is located on one side of the existing roadbed (1) and is adapted to the existing roadbed (1). The replacement foundation (3) is located below the support truss (2). The replacement foundation (3) is used to support the support truss (2) to prevent the support truss (2) from settling. The support truss (2) can withstand the upper load to prevent structural deformation.

2. The truss-type side-width structure of the roadbed according to claim 1, characterized in that, The supporting truss (2) is provided with diagonal bracing (21).

3. The truss-type side-width structure of the roadbed according to claim 1, characterized in that, A rigid base plate (4) is provided between the supporting truss (2) and the replacement foundation (3).

4. The truss-type side-width structure of the roadbed according to claim 3, characterized in that, The width of the rigid base plate (4), the width of the replacement foundation (3), and the width of the bottom of the supporting truss (2) are consistent.

5. The truss-type side-width structure of the roadbed according to claim 1, characterized in that, The top of the supporting truss (2) is provided with a panel assembly (5), and the height of the upper surface of the panel assembly (5) is the same as the height of the upper surface of the existing roadbed (1).

6. The truss-type side-width structure of the roadbed according to claim 5, characterized in that, The panel assembly (5) includes a first panel (51) and a second panel (52) stacked on top of each other. The lower surface of the first panel (51) is provided with a plurality of first stiffening ribs (53) along the width direction of the roadbed, and the upper surface of the second panel (52) is provided with a plurality of second stiffening ribs (54) along the width direction of the roadbed.

7. The truss-type side-width structure of the roadbed according to claim 1, characterized in that, It includes several support trusses (2), which are spliced ​​together in sequence along the length of the roadbed. Each of the support trusses (2) is provided with a counterweight (22) and a slide rail (23). The slide rail (23) is set along the width of the roadbed. The counterweight (22) can slide along the slide rail (23) to adjust the center of gravity of the support truss (2).

8. The truss-type side-width structure of the roadbed according to any one of claims 1 to 7, characterized in that, The filler material in the replacement foundation (3) includes lightweight concrete.

9. A design method for a truss-type side-width structure of a roadbed, characterized in that, The truss-type side-width structure for designing and verifying the roadbed according to any one of claims 1 to 8, wherein the supporting truss (2) is provided with a counterweight (22) and a slide rail (23), a rigid base plate (4) is provided between the supporting truss (2) and the replacement foundation (3), a panel assembly (5) is provided on the top of the supporting truss (2), and a track (6) and a vehicle (7) are provided on the panel assembly (5); the design method includes zero-additional-load verification, the zero-additional-load verification including: S1: Calculate the load G1 of the slide rail (23) per meter along the length of the roadbed, the load G2 of the counterweight block (22), the load G3 of the original foundation soil of the replacement foundation (3) before replacement, the load G4 of the rigid base plate (4), and the load G5 of the replacement foundation (3): ； ； ； ； ； In the above formulas: F1 is the load of the slide rail (23), F2 is the load of the counterweight (22), and D 1~2 The distance between two adjacent sets of the slide rails (23) and the counterweight (22) along the length direction of the roadbed, γ3 is the unit weight of the original foundation soil, γ4 is the unit weight of the rigid base plate (4), γ5 is the unit weight of the replacement foundation (3), S3 is the area of ​​the original foundation soil in the cross-sectional direction of the roadbed, S4 is the area of ​​the rigid base plate (4) in the cross-sectional direction of the roadbed, and S5 is the area of ​​the replacement foundation (3) in the cross-sectional direction of the roadbed. S2: Calculate the total load G of the sidewall structure and track (6) and vehicle (7) loads per meter along the length of the roadbed: G = G1 + G2 + G4 + G5 + G6 + G7 + G8; Wherein: G6 is the load of the vehicle (7) per meter along the length of the roadbed, G7 is the load of the track (6) per meter along the length of the roadbed, and G8 is the load of the support truss (2) per meter along the length of the roadbed. S3: Determine the difference between G and G3. If G≤G3, then the baffle structure has no settlement.

10. The design method for the truss-type side-width structure of the roadbed according to claim 9, characterized in that, It also includes total load eccentricity check and minimum eccentricity check for the most unfavorable load. The total load eccentricity check must satisfy the following formula: G7L7+G8L8=G2L2; The most unfavorable load small eccentricity check must satisfy the following formula: ； Wherein: L7 is the horizontal distance between the load of the panel assembly (5) and the track (6) and the center line of the rigid base plate (4), L8 is the horizontal distance between the support truss (2) and the center line of the rigid base plate (4), L2 is the horizontal distance between the counterweight (22) and the center line of the rigid base plate (4), L6 is the horizontal distance between the load of the vehicle (7) and the center line of the rigid base plate (4), and B4 is the width of the rigid base plate (4).

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