CN117932884A - Guardrail retaining wall separation design method for weakening vehicle impact effect - Google Patents
Guardrail retaining wall separation design method for weakening vehicle impact effect Download PDFInfo
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- CN117932884A CN117932884A CN202311783069.1A CN202311783069A CN117932884A CN 117932884 A CN117932884 A CN 117932884A CN 202311783069 A CN202311783069 A CN 202311783069A CN 117932884 A CN117932884 A CN 117932884A
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- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000013461 design Methods 0.000 title claims abstract description 18
- 238000000926 separation method Methods 0.000 title claims abstract description 17
- 230000003313 weakening effect Effects 0.000 title claims abstract description 13
- 230000000694 effects Effects 0.000 title claims abstract description 10
- 230000008859 change Effects 0.000 claims abstract description 12
- 230000008569 process Effects 0.000 claims abstract description 10
- 229910000831 Steel Inorganic materials 0.000 claims description 21
- 239000010959 steel Substances 0.000 claims description 21
- 239000004567 concrete Substances 0.000 claims description 14
- 238000004364 calculation method Methods 0.000 claims description 10
- 230000004888 barrier function Effects 0.000 claims description 9
- 230000005484 gravity Effects 0.000 claims description 6
- 230000033001 locomotion Effects 0.000 claims description 4
- 239000004575 stone Substances 0.000 claims description 4
- 230000001133 acceleration Effects 0.000 claims description 3
- 230000009471 action Effects 0.000 abstract description 3
- 238000010276 construction Methods 0.000 description 2
- 230000003116 impacting effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
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Abstract
The invention discloses a guardrail retaining wall separation design method for weakening the impact effect of a vehicle, wherein a buffer layer is arranged between a guardrail and the retaining wall; the thickness of the buffer layer is delta; the design method of delta comprises the following steps: calculating the lateral change distance delta S of the mass center in the collision process of the vehicle; calculating uniform deceleration a perpendicular to the guardrail during the change of the moving track of the vehicle according to the transverse change distance delta S of the mass center; in the process of calculating the collision guardrail of the vehicle according to the uniform deceleration a, the average impact force P Z transmitted to the guardrail is calculated; estimating a peak impact force P m x ax and a vehicle lateral maximum deceleration a max during a collision from the uniform deceleration a and the average impact force P Z; the thickness of the cushion layer is calculated as Δ from the peak impact force P m x ax and the vehicle transverse direction maximum deceleration a max. The stability and the safety of the fabricated retaining wall structure under the impact action of the wall top guardrail vehicle under the normal use condition are guaranteed, and the potential safety hazard of the roadbed is reduced.
Description
Technical Field
The invention relates to the technical field of roadbed and pavement protection engineering, in particular to a guardrail retaining wall separation design method for weakening the impact effect of vehicles.
Background
The prefabricated retaining wall can be used for newly-built, newly-built and newly-built road sections, is used as road shoulder walls, is often linear engineering, can also be used as old road longitudinal slope elevation, and is used as a temporary retaining wall for a central separation belt. The retaining wall not only needs a large amount, but also has a single structural form and has a prefabricated and assembled foundation. The prefabricated retaining wall is manufactured by prefabricated factory production and standardized maintenance of the retaining wall components through special dies, and is assembled and formed after being transported to a construction site after reaching strength, so that the design standardization, the production process standardization and the site construction mechanization of the retaining wall components are realized, and the retaining wall has good economical efficiency.
However, with increasing traffic in China, accidents of vehicles striking the guard rail at the top of the wall occur, various problems and structural diseases of the road shoulder retaining wall structure are caused, the road shoulder retaining wall is influenced by light people, the durability of the retaining wall is reduced and even the bearing capacity is lost when serious, the roadbed collapses, and the potential safety hazard is large. Therefore, it is necessary to take safety measures in advance, so as to ensure the bearing performance and normal use performance of the retaining wall structure, avoid damaging the retaining wall under the action of the vehicle impacting the guard rail on the top of the wall, ensure the safety of the subgrade and the road surface of the road, and improve the service life of the retaining wall structure. Aiming at the current situation, a guardrail retaining wall separation design method for weakening the impact effect of a vehicle is needed.
Disclosure of Invention
The aim of the invention can be achieved by the following technical scheme:
a guardrail retaining wall separation design method for weakening the impact effect of a vehicle is provided, and a buffer layer is arranged between a guardrail and the retaining wall; the thickness of the buffer layer is delta; the design method of delta comprises the following steps:
calculating the lateral change distance delta S of the mass center in the collision process of the vehicle; the calculation formula is as follows:
ΔS＝C sinθ+b cosθ-b+Δ
wherein C is the distance from the center of gravity of the vehicle to the front bumper; θ is a vehicle collision angle; b is half the vehicle width;
calculating uniform deceleration a perpendicular to the guardrail during the change of the moving track of the vehicle according to the transverse change distance delta S of the mass center; the calculation formula is as follows:
Wherein v 1 is the vehicle running speed before the guardrail is impacted, v 2 is the vehicle running speed after the guardrail is impacted, and v x is the transverse movement speed before the vehicle impacts the guardrail, namely v x＝v1 sin theta;
In the process of calculating the collision guardrail of the vehicle according to the uniform deceleration a, the average impact force P x transmitted to the guardrail is calculated; the calculation formula is as follows:
Wherein m is the mass of the vehicle; w is the weight of the vehicle; g is gravity acceleration;
Estimating peak impact force during a collision from uniform deceleration a and average impact force P x And a vehicle lateral maximum deceleration a max; wherein/>
According to peak impact forceAnd the vehicle transverse maximum deceleration a max calculates the thickness of the buffer layer as delta; the formula is as follows:
as a further scheme of the invention: peak impact force 2-3 Times the average impact force P x.
As a further scheme of the invention: the buffer layer between the guardrail and the retaining wall adopts a rubble layer meeting the requirements of elastic modulus and hardness.
As a further scheme of the invention: the guardrail adopts the form of concrete anticollision fence, and the bottom is sunk in the road bed.
As a further scheme of the invention: a settlement joint with a 1cm interval is arranged between adjacent guardrails.
As a further scheme of the invention: the bottom of the guardrail is connected with a plurality of steel pipe piles which are longitudinally distributed along the road; and one end of the steel pipe pile is buried into the roadbed, and the other end of the steel pipe pile is buried into the guardrail.
As a further scheme of the invention: concrete cushion blocks are arranged at the bottom of the retaining wall; the concrete cushion block is arranged on the broken stone cushion layer.
The invention has the beneficial effects that:
According to the guardrail retaining wall separation design method, in transverse arrangement, the retaining wall and the guardrail are separated and designed at a certain distance delta, so that the influence of impact load of vehicles on the retaining wall is weakened to a certain extent, the stability and safety of the assembled retaining wall structure under the impact action of the guardrail vehicles on the top of the wall are ensured under the normal use condition, the potential safety hazard of roadbed is reduced, the service life of the retaining wall design is ensured, and the method has important significance for promoting sustainable development of society.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 is a transverse layout of a barrier retaining wall separation design that weakens the impact of a vehicle;
fig. 2 is a schematic view of a vehicle crash barrier model of the invention.
In the figure, 1, a guardrail; 2. a retaining wall; 3. a steel pipe pile; 4. concrete cushion block
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, a number means one or more, a number means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
Referring to fig. 1-2, the present invention is a method for designing a barrier retaining wall separation for weakening the impact of a vehicle, wherein a barrier 1 and a retaining wall 2 are separated by a certain distance delta in a transverse arrangement; the guardrails 1 are in a concrete anti-collision fence form, a settlement joint with a 1cm interval is arranged between adjacent guardrails 1, a buffer layer is arranged behind each guardrail 1, and the thickness is delta; roadbed of a certain depth is buried in the bottom of the guardrail 1, the foundation of the guardrail 1 adopts a steel pipe pile 3 foundation of a specific size, a part of steel pipe piles 3 are buried in the roadbed, a part of steel pipe piles 3 are buried in the concrete guardrail 1, the steel pipe piles 3 are arranged in the transverse direction, and the steel pipe piles are arranged at a certain interval along the longitudinal direction of the road. The bottom of the retaining wall 2 is provided with a concrete cushion block 4; the concrete cushion block 4 is arranged on the broken stone cushion layer.
Specifically, in some embodiments, the guardrails 11 are in the form of concrete anti-collision guardrails, the longitudinal length of each cast-in-situ guardrail 1 is 15-30m, a settlement joint with a 1cm interval is arranged between adjacent guardrails 11, and delta soil layer with a certain thickness is arranged behind each guardrail 11 for buffering; the roadbed with a certain depth is buried at the bottom of the guardrail 11 by about 10cm, the foundation of the guardrail 11 is based by adopting steel pipe piles 33 with specific dimensions (such as steel pipe piles 3 with the diameter of 140mm and the thickness of 4.5 mm), a part of the steel pipe piles 33 are buried in the roadbed by about 1.3m, a part of the steel pipe piles 33 are buried in the concrete guardrail 1 by about 0.4m, one steel pipe pile 33 is arranged in the transverse direction, and one steel pipe pile 33 is arranged at certain intervals (generally 1 m) along the longitudinal direction of the road.
The soil layer buffer thickness delta is a value obtained according to a motion track of a vehicle which obliquely collides with the guardrail 1 at a certain angle theta and then turns to slide along the guardrail 1 for a certain distance, and the impact force P of the vehicle collision process can be obtained by multiple real-vehicle full-scale collision tests or simulation calculation and analysis by combining with fig. 2; the design method of delta comprises the following steps:
calculating the lateral change distance delta S of the mass center in the collision process of the vehicle; the calculation formula is as follows:
ΔS＝C sinθ+b cosθ-b+Δ
wherein C is the distance from the center of gravity of the vehicle to the front bumper; θ is a vehicle collision angle; b is half the vehicle width;
calculating the change period of the vehicle running track according to the centroid transverse change distance delta S, wherein the uniform deceleration a perpendicular to the guardrail 1 is known from a kinematic equation; the calculation formula is as follows:
Wherein v 1 is the vehicle running speed before the guardrail 1 is impacted, v 2 is the vehicle running speed after the guardrail 1 is impacted, and v x is the transverse movement speed before the guardrail 1 is impacted, namely v x＝v1 sin theta;
In the process of calculating the collision guardrail 1 of the vehicle according to the uniform deceleration a, the average impact force P x transmitted to the guardrail 1 is calculated; the calculation formula is as follows:
Wherein m is the mass of the vehicle; w is the weight of the vehicle; g is gravity acceleration;
Estimating peak impact force during a collision from uniform deceleration a and average impact force P x And a vehicle lateral maximum deceleration a max; wherein/>
According to peak impact forceAnd the vehicle transverse maximum deceleration a max calculates the thickness of the buffer layer as delta; the formula is as follows:
it should be noted that, considering that the impact force is generally an average impact force of 0.2-0.3 seconds during a collision, peak impact force occurs during this process About 2-3 times the average impact force P x; the relation between the collision force and the time is generally sinusoidal, and the vehicle transverse maximum deceleration/>, then
The buffer layer between the guard rail 1 and the retaining wall 2 adopts a rubble layer meeting the requirements of elastic modulus and hardness. Generally, it is desirable to use a gravel clay having a high modulus of elasticity and a high hardness.
A part of the reduced kinetic energy of the impacting vehicle is converted into structural internal energy of the vehicle, the structural internal energy causes deformation damage of the vehicle, and the other part of the reduced kinetic energy is sequentially transmitted to structures such as the guardrail 1, the steel pipe piles 3, the roadbed, the retaining wall 2 and the like and is converted into structural internal energy to cause stress and deformation of the structural internal energy; the structures with larger absorption internal energy are roadbed, retaining wall 2, concrete cushion block 4 and the like in sequence, while the internal energy absorbed by the guard rail 1 and the steel pipe pile 3 is smaller, on one hand, due to the small structural body quantity, and on the other hand, due to the fact that the functions of the guard rail 1 and the steel pipe pile are mainly force transmission structures rather than stress structures; therefore, in order to weaken the impact effect of the vehicle and increase the anti-overturning capacity of the retaining wall 2 after the impact, the foundation of the retaining wall 2 adopts a gravelly cushion layer with larger strength, and the root part of the retaining wall is provided with a foundation reinforced concrete cushion block 4.
The foregoing describes one embodiment of the present invention in detail, but the description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. All such equivalent changes and modifications as come within the scope of the following claims are intended to be embraced therein.
Claims (7)
1. A guardrail retaining wall separation design method for weakening the impact effect of a vehicle is characterized in that a buffer layer is arranged between a guardrail (1) and a retaining wall (2) in transverse arrangement; the thickness of the buffer layer is delta; the design method of delta comprises the following steps:
calculating the lateral change distance delta S of the mass center in the collision process of the vehicle; the calculation formula is as follows:
ΔS＝Csinθ+bcosθ-b+Δ
wherein C is the distance from the center of gravity of the vehicle to the front bumper; θ is a vehicle collision angle; b is half the vehicle width;
Calculating uniform deceleration a perpendicular to the guardrail (1) during the change of the vehicle running track according to the centroid transverse change distance delta S; the calculation formula is as follows:
Wherein v 1 is the vehicle running speed before the guardrail (1) is impacted, v 2 is the vehicle running speed after the guardrail (1) is impacted, and v x is the transverse movement speed before the guardrail (1) is impacted, namely v x＝v1 sin theta;
In the process of calculating the collision guardrail (1) of the vehicle according to the uniform deceleration a, the average impact force P x transmitted to the guardrail (1) is calculated; the calculation formula is as follows:
Wherein m is the mass of the vehicle; w is the weight of the vehicle; g is gravity acceleration;
Estimating peak impact force during a collision from uniform deceleration a and average impact force P x And a vehicle lateral maximum deceleration a max; wherein/>
According to peak impact forceAnd the vehicle transverse maximum deceleration a max calculates the thickness of the buffer layer as delta; the formula is as follows:
2. the method for designing a barrier retaining wall separation for attenuating vehicular impact according to claim 1, wherein the peak impact force 2-3 Times the average impact force P x.
3. The method for designing a barrier retaining wall separation for weakening the impact of a vehicle according to claim 1, wherein the buffer layer between the barrier (1) and the retaining wall (2) is a crushed stone layer satisfying the elastic modulus and hardness requirements.
4. The method for designing a barrier retaining wall separation for weakening the impact of a vehicle according to claim 1, wherein the barrier (1) is in the form of a concrete bumper and the bottom is sunk into the subgrade.
5. The guardrail retaining wall separation design method for weakening the impact of a vehicle according to claim 1 is characterized in that a settlement joint with a distance of 1cm is arranged between adjacent guardrails (1).
6. The guardrail retaining wall separation design method for weakening the impact effect of vehicles according to claim 1 is characterized in that the bottom of the guardrail (1) is connected with a plurality of steel pipe piles (3) which are longitudinally distributed along a road; one end of the steel pipe pile (3) is buried into the roadbed, and the other end of the steel pipe pile is buried into the guardrail (1).
7. The guardrail retaining wall separation design method for weakening the impact effect of a vehicle according to claim 1, wherein the bottom of the retaining wall (2) is provided with a concrete pad (4); the concrete cushion block (4) is arranged on the broken stone cushion layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311783069.1A CN117932884A (en) | 2023-12-22 | 2023-12-22 | Guardrail retaining wall separation design method for weakening vehicle impact effect |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311783069.1A CN117932884A (en) | 2023-12-22 | 2023-12-22 | Guardrail retaining wall separation design method for weakening vehicle impact effect |
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| CN117932884A true CN117932884A (en) | 2024-04-26 |
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| CN202311783069.1A Pending CN117932884A (en) | 2023-12-22 | 2023-12-22 | Guardrail retaining wall separation design method for weakening vehicle impact effect |
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- 2023-12-22 CN CN202311783069.1A patent/CN117932884A/en active Pending
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