Novel high-speed railway roadbed structure and vibration reduction method thereof
By designing upper and lower vibration damping plates in the high-speed railway subgrade structure, using periodic structure theory and resonance principle to perform vibration isolation and absorption for vibrations in different frequency segments, the poor vibration isolation effect and construction area in the existing technology are solved. The problem has achieved efficient and economical vibration reduction effect.
Patent Information
- Application Number
- CN202411486538.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2024-12-27
AI Technical Summary
The existing high-speed railway subgrade structure has limited effect in reducing the environmental harm of train vibration. It is difficult for traditional vibration isolation structures to isolate specific frequency segments, and there are problems of vibration energy reflection and increase construction area.
Using a new subgrade structure including upper vibration damping plate and lower vibration damping plate, the materials and dimensions of vibration isolation structural units are determined through field testing and numerical simulation, and the periodic structure theory and resonance principle are used to design for high frequencies above 50Hz and 0- Low-frequency vibration at 50Hz performs vibration isolation and absorption.
It has achieved efficient vibration reduction of the high-speed railway subgrade structure, avoided secondary environmental pollution, strong construction feasibility and high economicality, and has dual effects of vibration isolation and vibration absorption.
Smart Images
Figure CN119194920A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a roadbed structure, in particular to a new type of high-speed railway roadbed structure and a vibration reduction method thereof, and belongs to the field of railway engineering construction. Background Art
[0002] The present invention belongs to the environmental vibration control of high-speed railway operating roadbed. With the increase of high-speed train running speed, the harm of environmental vibration is becoming increasingly prominent. Among them, low-frequency vibration waves have slow natural decay, long propagation distance, and strong destructiveness, which seriously affects the structural safety of nearby sensitive buildings and human health. Therefore, how to effectively and economically reduce such vibration is of great significance.
[0003] Current vibration isolation methods include active vibration isolation and passive vibration isolation. Active vibration isolation includes designing vibration-reducing cushions and optimizing rail roughness. Admittedly, active vibration isolation is the primary task of vibration isolation design. However, due to the actual structural form and objective technical constraints, the effect of active vibration isolation is very limited, and more vibration energy is transmitted and dispersed through the roadbed and foundation. Passive vibration isolation is to set up vibration isolation structures in the roadbed or foundation to block or avoid the impact of vibration waves on sensitive structures. Therefore, in a sense, passive vibration isolation still plays an irreplaceable role in vibration isolation design. At present, there are many vibration isolation structures, such as vibration isolation trenches, walls, piles, etc.
[0004] Defects of the existing technology: First, the trenches, walls and piles in the traditional methods are difficult to isolate vibrations in specific frequency bands, and usually they are all-inclusive and have low vibration isolation efficiency; second, the trenches, walls and piles are mainly vibration isolation structures, and their vibration absorption capacity is poor, so the vibration energy may be reflected back to the roadbed, thereby posing a threat to the stability of the roadbed; finally, the vibration isolation trenches, walls, piles, etc. themselves do not belong to the scope of railway roadbed construction, so the construction of vibration isolation trenches, walls and piles will increase the area occupied by the railway, which may have an impact on the environment along the line, and the vibration isolation trenches, walls and piles only play a vibration isolation role, and the cost of vibration isolation management is relatively high. Summary of the invention
[0005] In order to solve the defects existing in the prior art, the present invention discloses a new type of high-speed railway roadbed structure, and its technical solution is as follows: A new type of high-speed railway roadbed structure, including vibration reduction and isolation, is characterized in that the vibration reduction and isolation includes two parts: the first part is an upper vibration reduction plate on the base bed, which is mainly for high-frequency vibrations above 50 Hz caused by trains; the second part is a "lower vibration reduction plate" under the roadbed, which mainly absorbs low-frequency vibrations of 0-50 Hz and reduces the harm of train operation vibrations to the environment.
[0006] The present invention also discloses a novel high-speed railway subgrade structure vibration reduction method, which is based on the above subgrade structure and includes the following steps: (1) Through on-site testing, the main frequency of vibration f1 of the base surface and the main frequency of ambient vibration f2 are measured; (2) Select the material of the vibration isolation structure unit and measure the main mechanical parameters of the material, including elastic modulus, Poisson's ratio and density; (3) Through the material resonance formula Or the numerical simulation method is used to deduce the size parameters of the vibration isolation structure unit; where k is the rubber stiffness per unit length, and m is the core mass per unit length; (4) Prefabricate vibration isolation structural units according to materials and sizes; (5) Based on the measured vibration acceleration amplitude and referring to the allowable vibration acceleration amplitude, the number of rows n of each type of vibration isolation structural unit is preliminarily determined through numerical simulation.
[0007] The present invention also discloses a novel high-speed railway, which is characterized in that it comprises a roadbed, and the roadbed adopts the above-mentioned roadbed structure.
[0008] The present invention also discloses a novel high-speed railway, which is characterized by comprising a roadbed and a roadbed vibration reduction device; the roadbed vibration reduction device is arranged on the roadbed, and the roadbed vibration reduction device adopts the above-mentioned roadbed vibration reduction method to achieve roadbed vibration reduction. Beneficial Effects
[0009] The vibration reduction and isolation roadbed structure proposed by the present invention is improved on the basis of the existing pile-plate structure roadbed structure, which can avoid secondary adverse effects on the environment. Secondly, the upper and lower vibration reduction plates can be prefabricated and then constructed according to the existing pile-plate structure roadbed construction method, so this method has strong feasibility and high economy.
[0010] The new roadbed structure takes into account both high-frequency and low-frequency vibrations, and has vibration isolation and vibration absorption effects. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 The invention discloses a novel high-speed railway roadbed structure, wherein: the vibration damping plate is arranged on the base bed, and the lower vibration damping plate is arranged between the pile foundation and the roadbed; Figure 2 This is a schematic diagram of a vibration-damping concrete slab of the present invention; Figure 3 Schematic diagram of the vibration reduction unit of the present invention; wherein the vibration reduction plate is formed by periodically arranging the vibration reduction units; Figure 4 It is the vibration attenuation curve of the new roadbed at different frequencies; Figure 5 Comparison cloud diagram of vibration reduction effect between new and control roadbed at 4.5Hz; Figure 6 Comparison cloud chart of vibration reduction effect between new and control roadbeds at 25Hz.
[0012] Wherein: track plate (1), upper vibration damping plate (2), base bed (3), roadbed (4), lower vibration damping plate (5), pile foundation (6), foundation (7), concrete (8), rubber (9), iron core (10). DETAILED DESCRIPTION Example 1
[0013] See also Figure 1-3 A new type of high-speed railway subgrade structure includes vibration reduction and isolation, and the vibration reduction and isolation includes two parts: the first part is an upper vibration reduction plate on the subgrade, which is mainly used for high-frequency vibrations above 50 Hz caused by trains; the second part is a lower vibration reduction plate under the subgrade, which mainly absorbs low-frequency vibrations of 0-50 Hz and reduces the harm of train running vibrations to the environment; the track plate is laid on the upper vibration reduction plate, and the subgrade is laid under the upper vibration reduction plate; the subgrade is laid on the lower vibration reduction plate, and pile foundations and foundations are laid under the lower vibration reduction plate; the vibration reduction plate includes concrete (8) and vibration reduction units; the vibration reduction units are periodically arranged in the concrete; the vibration reduction units include a rubber layer (9) and an iron core A (10); the iron core A is arranged in the rubber layer (9) (10), the rubber is a high elastic damping rubber material, and the rubber thickness is determined according to the main vibration frequency of the roadbed and the environmental vibration; the vibration reduction unit has a length a of 0.4-0.8m, a width b of 0.1-0.5m, and a radius r of 0.1-0.3b; the iron core A in the vibration reduction unit is a high-density metal material; the upper vibration reduction plate targets a higher frequency f1 and has a smaller rubber thickness; the lower vibration reduction plate targets a lower frequency f2 and has a larger rubber thickness; if the main vibration frequency of the environmental vibration is more, or the frequency band is wider, the rubber thickness in the vibration reduction plate can take multiple values to meet the purpose of wide-band vibration isolation.
[0014] a is taken as 0.4-0.8m; b is taken as 0.1-0.5m; the iron core in the vibration reduction unit is made of iron or other high-density metal materials, and the radius r is taken as 0.1-0.3b; the rubber is a high-elasticity damping rubber material, and the thickness is determined based on the main vibration frequency of the roadbed and environmental vibration. Example 2
[0015] A novel high-speed railway subgrade structure vibration reduction method, based on the above subgrade structure, comprises the following steps: (1) Acceleration sensors are placed on the surface of the subgrade and at a certain distance (10-30m) from the roadbed. When a train passes by, the sensor data is collected to obtain a vibration time history curve. The vibration time history curve is subjected to Fourier transform to obtain the main vibration frequencies f1 and f'1, which correspond to the vibration of the subgrade surface and a certain distance from the roadbed, respectively. The test position is changed and the above two steps are repeated twice to obtain three sets of vibration main frequency data f1, f2, f3, and f'1, f'2, f'3. The average value fa of f1, f2, and f3 is taken as the main vibration frequency of the subgrade surface, and the average value fb of f'1, f'2, and f'3 is taken as the main vibration frequency of the environment. (2) Select vibration isolation structural unit materials, such as concrete, rubber, and iron, and make three batches of specimens, a total of 9 specimens; select the MTS-815 testing machine to test the first batch of concrete specimens, and obtain the stress-strain curve and transverse and longitudinal deformation values; solve the elastic modulus E1 of the material based on the stress-strain curve; solve the Poisson's ratio v1 of the material based on the transverse and longitudinal deformation values of the specimens; repeat the above steps, test the second and third batches of concrete specimens respectively, and obtain the elastic modulus E2 and E3, as well as the Poisson's ratio v2 and v3. Take the average value Ea of E1, E2, and E3 as the elastic modulus of concrete, and take the average value va of v1, v2, and v3 as the Poisson's ratio of concrete; select the MTSInsight 30 testing machine, repeat the above test steps, test the rubber specimens, and calculate the rubber elastic modulus Eb and Poisson's ratio vb; select the INSTRON 1346 testing machine, repeat the above test steps, measure the iron specimens, and calculate the elastic modulus Ec and Poisson's ratio vc of iron; (3) Calculate the masses m1, m2, and m3 of the three groups of concrete samples by weighing; calculate the volumes V1, V2, and V3 of the concrete samples according to the standard sample dimensions; calculate the densities r1, r2, and r3 of the concrete samples; take the average value ra of r1, r2, and r3 as the concrete density; repeat the above steps to calculate the density rb of rubber and the density rc of iron; (4) Calculate the structural natural frequency using the formula Or numerical simulation method, using the control variable method, to deduce the core radius r and rubber thickness d; where k is the rubber stiffness per unit length, and m is the core mass per unit length; (5) Prefabricate vibration isolation structural units according to material dimensions.
[0016] (6) The vibration isolation structural units in the surface layer of the subgrade are arranged in a full-paving manner; the vibration isolation structural units in the road subgrade are arranged from both ends to the middle, and the number of arrangements is n; (7) Select several test points at different distances from the railway, and test the ground vibration acceleration amplitude A1, A2, A3... when the train passes by; determine the maximum vibration acceleration values B1, B2, B3... allowed at different distances according to the environmental vibration standards related to train operation; let the target attenuation coefficient Wn =(An-Bn) / Bn, n=1,2,3…; Through numerical simulation, when no vibration isolation structure unit is set up, the vibration acceleration values Aa, Ab, Ac… of measuring points at different distances are calculated; n takes the initial value 2 for simulation, and calculates the acceleration values Ba, Bb, Bc… of the corresponding measuring points; calculates the simulation attenuation coefficient M n =(Aa-Ba) / Ba,n=1,2,3…;Comparison W n and M n Size value, for any value of n, when W n > M n When n is n+2, the above steps are repeated until W n < M n Until establishment.
[0017] Figure 4-6 They are respectively vibration attenuation curves at different frequencies of the new roadbed obtained by using the vibration reduction method and vibration reduction structure of the present invention; a contrast cloud diagram of vibration reduction effects between the new and control roadbeds at 4.5 Hz; and a contrast cloud diagram of vibration reduction effects between the new and control roadbeds at 25 Hz.
[0018] The present invention is designed based on the local resonance mechanism in the periodic structure theory. According to the periodic structure energy band theory, a band gap is generated in a specific frequency band. The vibration wave in the band gap cannot propagate in the periodically arranged vibration reduction structure, thereby achieving the purpose of vibration isolation. Secondly, according to the resonance principle, the energy of the isolated vibration wave will gradually transfer to the "iron core" vibrator and finally be absorbed by the "rubber layer". Therefore, the vibration reduction and isolation roadbed structure has both vibration isolation and vibration absorption effects.
[0019] The vibration reduction and isolation of the new high-speed railway roadbed structure of the present invention mainly includes two parts. The first part is the "upper vibration reduction plate" on the base bed, which is mainly used for high-frequency vibrations above 50Hz caused by trains. Long-term high-frequency vibrations may cause the fine particles of the roadbed to loosen and accelerate the damage of the roadbed. The second part is the "lower vibration reduction plate" under the roadbed, which mainly absorbs low-frequency vibrations of 0-50Hz and reduces the harm of train running vibrations to the environment.
[0020] Finally, the vibration reduction and isolation roadbed structure proposed by the present invention is improved on the basis of the existing pile-plate roadbed structure, so the present invention can avoid secondary adverse effects on the environment. Secondly, the upper and lower vibration reduction plates can be prefabricated and then constructed according to the existing pile-plate roadbed construction method, so this method is highly feasible and economical.
[0021] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.
Claims
1. A new type of high-speed railway subgrade structure, including vibration reduction and isolation, characterized by: The vibration reduction and isolation includes two parts: the first part is the upper vibration reduction plate on the base bed, which is mainly used for high-frequency vibrations above 50Hz caused by trains; the second part is the lower vibration reduction plate under the roadbed, which mainly absorbs low-frequency vibrations of 0-50Hz and reduces the harm of train operation vibrations to the environment.
2. The new high-speed railway subgrade structure according to claim 1 is characterized by: The track plate is laid on the upper vibration damping plate, and the base bed is laid under the upper vibration damping plate; the roadbed is laid on the lower vibration damping plate, and the pile foundation and the foundation are laid under the lower vibration damping plate.
3. The new high-speed railway subgrade structure according to claim 1 is characterized by: The vibration damping plate comprises concrete (8) and vibration damping units; the vibration damping units are periodically arranged in the concrete.
4. The new high-speed railway subgrade structure according to claim 3 is characterized by: The vibration reduction unit comprises a rubber layer (9) and an iron core A (10); the iron core A (10) is arranged in the rubber layer (9); the rubber is a high elastic belt damping rubber material; and the thickness of the rubber is determined by calculation based on the main vibration frequency of the roadbed and the environmental vibration.
5. The new high-speed railway subgrade structure according to claim 3 is characterized by: The vibration reduction unit has a length a of 0.4-0.8 m, a width b of 0.1-0.5 m, and a radius r of 0.1-0.3b; the iron core A in the vibration reduction unit is made of high-density metal material.
6. The new high-speed railway subgrade structure according to claim 4 is characterized by: The upper vibration damping plate targets a higher frequency f1 and has a smaller rubber thickness; the lower vibration damping plate targets a lower frequency f2 and has a larger rubber thickness; if the main vibration frequencies of the ambient vibration are high or the frequency band is wide, the rubber thickness in the vibration damping plate can take multiple values to meet the purpose of wide-band vibration isolation.
7. A novel high-speed railway subgrade structure vibration reduction method, the method is based on the subgrade structure according to any one of claims 1 to 6, and is characterized by: The steps include: (1) Through on-site testing, the main frequency of vibration f1 of the base surface and the main frequency of ambient vibration f2 are measured; (2) Select the material of the vibration isolation structure unit and measure the main mechanical parameters of the material, including elastic modulus, Poisson's ratio and density; (3) Through the material resonance formula Or the numerical simulation method is used to deduce the size parameters of the vibration isolation structure unit; where k is the rubber stiffness per unit length, and m is the core mass per unit length; (4) Prefabricate vibration isolation structural units according to materials and sizes; (5) Based on the measured vibration acceleration amplitude and referring to the allowable vibration acceleration amplitude, the number of rows n of each type of vibration isolation structural unit is preliminarily determined through numerical simulation.
8. A new type of high-speed railway, characterized by: It comprises a roadbed, and the roadbed adopts the roadbed structure described in any one of claims 1-6.
9. A new type of high-speed railway, characterized by: It comprises a roadbed and a roadbed vibration reduction device; the roadbed vibration reduction device is arranged on the roadbed, and the roadbed vibration reduction device adopts the roadbed vibration reduction method described in claim 7 to achieve roadbed vibration reduction.