CN104847384A - Vibration and noise reduction method for subway intersectional tunnels - Google Patents

Abstract

The invention belongs to the field of rail transit vibration reduction and noise reduction, and relates to a method for vibration reduction and noise reduction of tunnels in subway intervals. In the present invention, a vibration-reducing and noise-reducing material is arranged on the inner side of the segment, and a vibration-reducing and noise-reducing slurry is injected on the outer side of the segment; times the length of the sensitive building; the vibration and noise reduction material inside the segment refers to rubber concrete with a thickness of 3-5cm; the outside of the segment refers to the area below the elevation line of the track bed, and the length along the subway running direction is greater than 2 times the length of the sensitive building; the vibration and noise reduction material on the outside of the segment refers to the vibration and noise reduction slurry, with a thickness of 3-8cm. The invention cuts off the transmission path of the vibration wave by increasing the damping coefficient of the segment, effectively reducing the impact of the vibration on the surrounding environment; and the selected material belongs to waste utilization, which is environmentally friendly, economical, and low in cost; and the construction process is simple.

Description

A Method for Vibration and Noise Reduction in Subway Interval Tunnels

technical field

The invention belongs to the field of rail transit vibration reduction and noise reduction, and relates to a method for vibration reduction and noise reduction of tunnels in subway intervals.

Background technique

Urban rail transit is an ideal means of transport with large capacity, safety, speed, punctuality, convenience and comfort, and has functions such as low energy consumption, less pollution, safety and comfort, and has a special status and role in solving urban traffic problems At present, 38 cities in China have approved the construction of urban subway projects. From now until 2020, it is estimated that about 2.5 trillion yuan will be invested in the construction of urban subway projects. Subway construction will also continue to advance rapidly.

On the other hand, with the improvement of living standards, people's requirements for quality of life are becoming more and more stringent than before, and the environmental vibration problems caused by the rapid development of rail transit have aroused strong reactions from the public. This is mainly because subway lines often pass through densely populated areas of the city, downtown areas with many buildings, scenic spots, and science and technology parks, etc., and the upper part or adjacent areas may be residential buildings, precision instrument rooms, ancient buildings, etc. In areas sensitive to noise, when the subway train is running, the buildings or residents will be affected by the vibration and noise of the foundation or surface caused by it, and the residents and instruments in the building will also be affected by secondary vibration and secondary noise. Impact. In particular, the impact of vibration and noise on the environment after the completion of the subway network will become a public nuisance that cannot be ignored. This impact lasts for 20 hours a day, 365 days a year. In many countries in the world, the vibration and noise of trains have caused damage to buildings along the line and complaints from residents along the line that it affects their lives. For the subway construction period, there are similar vibration complaints and petitions, such as the construction disturbance incident of a certain line in Beijing, which then became a civil disturbance and became a social problem, affecting the construction of rail transit

According to the vibration generation mechanism, propagation law and response characteristics of the vibration object, the existing vibration reduction methods can reduce vibration and noise from three aspects: reducing the intensity of the vibration source, cutting off the vibration transmission path and building vibration isolation. Among them, reducing the intensity of the vibration source is the active control, and cutting off the vibration transmission path and building vibration isolation is the passive control.

Reduce the strength of the vibration source: (1) Use heavy-duty steel rails (above 60kg/m), and use seamless lines as much as possible, reduce the running speed of the train appropriately, rationally configure the axles, smooth the wheels, reduce the unsprung mass of the vehicle, and avoid The vehicle and the track resonate, which can reduce the vibration intensity by 10-15dB vibration.

Cutting off the transmission path: vibration isolation ditch, vibration isolation wall, vibration isolation piles, wave resistance blocks, etc.;

Vibration isolation of the vibration-receiving body: (1) building vibration isolation usually adopts increasing the stiffness and damping of the floor, setting up the floor vibration isolation system, building foundation vibration isolation, room-in-room technology, floating floor, etc.; (2) instrument vibration isolation adopts instrument Vibration isolation foundation, commercial vibration isolation platform, vibration isolation bunker; (3) Old buildings adopt structural maintenance reinforcement, repair, and weak foundation treatment.

At present, most of the vibration reduction is carried out for a specific project. There is a lack of unified design guidelines or specifications. It is imminent to seek economical, reasonable and effective vibration reduction measures. This kind of beneficial exploration enriches the existing vibration reduction measures.

Contents of the invention

In order to overcome the deficiencies in the prior art, the present invention aims to provide a method for reducing vibration and noise in subway interval tunnels, which is an active vibration isolation and noise reduction measure for subway vibration-sensitive areas, which can better reduce vibration caused by vibration. The occurrence of nuisance and nuisance problems caused by noise.

In order to achieve the above object, the present invention provides a method for vibration reduction and noise reduction in subway tunnels, which is characterized in that: a vibration reduction and noise reduction material is provided on the inner side of the segment, and a vibration reduction and noise reduction slurry is injected on the outer side of the segment;

The inner side of the segment refers to the area above the elevation line of the track bed, and the length along the running direction of the subway is greater than twice the length of the sensitive building; the vibration and noise reduction material inside the segment refers to rubber concrete with a thickness of 3-5cm; The damping ratio of free vibration at the first natural frequency of rubber concrete is 2%-4%, and the elastic modulus is 30000-500000MPa;

The outer side of the segment refers to the area below the elevation line of the ballast bed, and the length along the subway running direction is greater than twice the length of the sensitive building; the vibration and noise reduction material on the outer side of the segment refers to the vibration and noise reduction slurry, with a thickness of 3-8cm; the damping and noise-reducing material on the outside of the segment has a damping ratio of 0.1-0.3 for free vibration at the first-order natural frequency, an elastic modulus of 2-5GPa, and an expansion ratio of 2-3.

The vibration and noise reduction material inside the segments refers to rubber concrete, which attenuates low-frequency vibration waves. Generally, it can be reduced by 5 decibels. Theory and practice show that the farther the natural frequency of the material is from the excitation frequency, the less likely the object is to vibrate. Using flexible rubber concrete to spray on the segment can avoid resonance.

Due to the periodicity of the structure and the continuity of the material, the periodicity of the material density of the periodic structure can be obtained. The Fourier function is used to expand the periodicity of the structure and the periodicity of the material density, and the equations are obtained according to the corresponding boundary conditions. Solve the eigenvalues and eigenvectors of the equations to obtain the function of the elastic wave frequency and the periodic structure parameters. Since this function is periodic, there are frequencies that elastic waves cannot pass through. called the periodic bandgap. Therefore, pasting vibration-damping and noise-reducing materials on the inner side of the segment can effectively reduce the noise caused by the train vibration and its secondary vibration transmitted to the ground surface.

In the present invention, vibration-reducing and noise-reducing materials are arranged on the inner and outer sides of the segment, thereby forming a damping structure and actively isolating the propagation of vibration waves generated by train wheel rails. Generally, it can be reduced by 5-10 decibels. This method forms a complete closed area. On the one hand, it can reduce the transmission of vibration waves generated by the wheel-rail interaction to the surrounding rock-soil medium, thereby reducing the impact on surface buildings and residents. Vibration and noise reduction, the paved area forms a closed acoustic cavity, which reduces the impact of noise on passengers during train operation.

Compared with the prior art, the present invention has the following advantages:

By increasing the damping coefficient of the segment, the propagation path of the vibration wave is cut off, effectively reducing the impact of vibration on the surrounding environment; and the selected material is waste tires, which belong to waste utilization, which is environmentally friendly and economical, and the cost is low; the construction process is simple, Low requirements for alms utensils.

Description of drawings

Fig. 1, structural representation of the present invention.

Figure 2. Schematic diagram of the arrangement along the direction of the train.

Detailed ways:

In order to make the above objects, features and advantages of the present invention more comprehensible, the embodiments of the present invention will be further described in detail below in conjunction with specific implementation methods.

As shown in Figure 1, the inner side of the segment refers to the area above the elevation line of the track bed, and the outer side of the segment refers to the area below the elevation line of the track bed.

As shown in Figure 2, the length along the running direction of the train should be greater than twice the length of the sensitive building.

The vibration and noise reduction material inside the segments refers to rubber concrete, which attenuates low-frequency vibration waves. Generally, it can be reduced by 3 decibels. Rubber concrete consists of cement, sand, stones, admixtures, rubber, and water. The damping ratio of free vibration at the first order natural frequency of the material is 2%-4%, and the elastic modulus is 30000-500000MPa.

The construction process of vibration and noise reduction inside the segment is as follows: firstly, the original segment is cleaned and repaired; then the rubber concrete vibration and noise reduction layer is sprayed, and the spraying requirement is uniform, with a thickness of 3-5cm.

The vibration-damping and noise-reducing material on the outside of the segment can be, but not limited to, polyurethane resin material, which can meet the following conditions: the damping ratio of free vibration at the first-order natural frequency is 0.1-0.3, and the elastic modulus It is 2-5GPa, and the expansion ratio is 2-3.

The construction process of vibration and noise reduction inside the segment is as follows: connect the injection gun and the grouting pump with a high-pressure rubber hose, use a small multifunctional pneumatic grouting pump, and adopt a double-liquid grouting system to install the prepared vibration isolation and noise reduction The material resin is injected into the grouting hole together with the catalyst. According to the nature of the surrounding rock, the grouting pressure is determined to be 5MPa-8MPa. When the grouting pressure reaches 5MPa-8MPa or there is a large area of grout leakage, that is, the amount of grout leakage = the injection amount of the pump, complete the grouting of the current grouting hole.

Claims (1)

1. for a method for subway sectional tunnel vibration and noise reducing, it is characterized in that: vibration and noise reducing material is set in the inner side of section of jurisdiction, outside section of jurisdiction, carry out injection vibration and noise reducing slurries;

Refer to the region of more than railway roadbed elevation line inside described section of jurisdiction, the length along subway circulation direction is greater than the sensitivity building length of 2 times; Inside section of jurisdiction, vibration and noise reducing material refers to rubber concrete, and thickness is 3-5cm; The damping ratio 2%-4% of free vibration under the first natural frequency of rubber concrete, modulus of elasticity is 30000-500000MPa;

Refer to the region of below railway roadbed elevation line outside described section of jurisdiction, the length along subway circulation direction is greater than the sensitivity building length of 2 times; Vibration and noise reducing material outside section of jurisdiction refers to vibration and noise reducing slurries, and thickness is 3-8cm; The damping ratio 0.1 ~ 0.3 of free vibration under the vibration and noise reducing material first natural frequency outside section of jurisdiction, modulus of elasticity is 2-5GPa, and expansion ratio is 2 ~ 3.