CN104594136B - Subway damping vibration-isolating elasticity mixing light railway roadbed controls technique - Google Patents

Abstract

The invention discloses a shock-absorbing, vibration-isolating, elastic-mixed light-weight ballast bed control technology for subways. Since one of the materials of the elastic light-weight concrete layer is a light-weight material containing EPS particles, a vibrator is required in the construction process of the compound ballast bed. / rod makes the concrete dense, but EPS particles are easy to float during the vibration process, which affects the strength uniformity and quality control of the elastic mixed light track bed. The present invention adds different volume ratios of concrete and EPS particles during the concrete forming process. Proportion of polyacrylamide to control the floating of EPS particles. According to the process of the invention, a shock-absorbing and vibration-isolated metro hybrid elastic lightweight track bed can be obtained, which has obvious effects of shock-absorbing and vibration-isolation.

Description

Control technology of elastic hybrid lightweight ballast bed for subway shock absorption and vibration isolation

technical field

The invention relates to a control technology of subway shock-absorbing, vibration-isolation, elastic hybrid light track bed, which is a shock-absorbing and vibration-isolation subway hybrid elastic light track bed.

Background technique

With the acceleration of my country's subway construction and the continuous increase of operating mileage, ensuring the harmony and safety of subway operation is not only an important livelihood project, but also a strategic project for urban development of green economy, which is related to everyone's travel safety. In fact, many potential safety hazards and hazards have appeared in the operation of subways in cities such as Shanghai and Nanjing, such as suspension of operation for maintenance after accumulated settlement and differential settlement seriously exceeding the standard, vibration of subway trains aggravates the danger of water seepage and mud leakage in the lining structure, and even Problems such as the surrounding soil and lining voids are challenges that must be faced in the construction of urban rail transit. Another complaint is that the vibration of subway trains disturbs residents. The vibration caused by the operation of subway trains spreads outwards through the surrounding strata, further inducing secondary vibrations of buildings, which have a negative impact on the structural safety of buildings and the work and daily life of residents. considerable influence.

There are special reasons for these problems, which are determined by the characteristics of shallow buried subways in our country. The buried depth of most subways in my country is about 15m, which belongs to shallow buried subways. The vibration generated during the operation of shallow buried subway trains affects the work and life of residents along the subway lines. Long-term effects have caused the cumulative deformation of the soft soil around the subway to seriously exceed the standard, which has affected the safe operation of the subway and even caused hazards. For example, the maximum cumulative settlement of Shanghai Metro Line 1 is close to 30cm, and the annual maximum settlement difference reaches 3cm, which has seriously threatened the subway. The safe operation of the subway can only be operated at a speed limit, which reduces the operating efficiency of the subway. The buried depth of European and American subways is relatively large, but the corresponding construction cost will be much higher. Due to the complex working conditions faced by shallow-buried subways, on the one hand, the shallow soil layers are mostly Quaternary strata, with many weak soil layers, and the variation of physical and mechanical properties of the soil layers is very complicated; the subway line is long, passing through different soil layers or geology Units will encounter large rivers and lakes at the same time. The subway structure of the large rivers and lakes will inevitably bear high water pressure, and there will be pressurized groundwater. The environment is very complicated. Therefore, the shallow buried subway brings the following problems: ① It is difficult to control the cumulative deformation of the surrounding soft soil, ② The impact of the vibration of the subway train increases the adverse effects of the accumulated deformation and the durable anti-seepage of the lining structure.

In recent years, my country's subway transportation system has developed rapidly. Following the opening of Beijing, Shanghai, and Guangzhou subways, nearly 40 cities have begun or plan to build subways or light rails. Since the urban subway runs through the commercial center and dense residential areas in the city, the impact on the living environment of the surrounding buildings along the line cannot be ignored. The subway usually adopts an integral ballast bed structure. In order to increase the elasticity of the track, the rail fastener adopts a double elastic cushion design, that is, a rubber backing plate with a small static stiffness coefficient is set under the iron backing plate for the fastener between the rail and the sleeper. The following measures are usually taken to reduce the vibration of the vibration source:

1. Use heavy rails above 60kg/m, and use seamless lines as much as possible;

2. Reduce the unsprung mass of the vehicle to avoid resonance between the vehicle and the track, which can reduce the vibration intensity by 10dB±;

3. Appropriately increase the buried depth of the subway, so that the vibration amplitude will increase and attenuate as the distance (depth) increases;

4. Adopt suitable ballast bed and track structure, increase the elasticity of the track, and add a rubber backing plate with a small static stiffness coefficient, the vibration attenuation can reach 5-10dB, but the service life is short, the later vibration damping effect is poor, and it cannot be replaced.

Although these shock-absorbing measures have achieved certain effects, the cumulative deformation of the foundation under the subway caused by long-term periodic vibration has continued to increase, which has threatened the safe operation of the subway and greatly increased the operation and maintenance costs.

In the prior art, the ballast bed is usually poured with C35 concrete, which belongs to the rigid ballast bed and basically has no attenuation effect on train vibration. The basic ballast bed in the general section of the subway project does not adopt any shock-absorbing measures, but only adopts shock-absorbing facilities in the areas where hospitals, workshops, and institutions that require vibration reduction are located, such as floating slab ballast, elastic short sleeper integral ballast Rails, rubber pads and other measures are used for shock absorption, but these measures are difficult to achieve a good shock absorption and vibration isolation effect, the vibration attenuation is 6-10dB, and the service life is limited.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a metro shock-absorbing vibration-isolation elastic hybrid lightweight track bed control process to obtain a shock-absorbing and vibration-isolated subway hybrid elastic lightweight track bed with obvious shock-absorbing isolation vibration effect.

Technical scheme: in order to achieve the above object, the technical scheme adopted in the present invention is:

1. The control technology of subway shock-absorbing, vibration-isolating, elastic-hybrid lightweight ballast bed, including the following steps:

1), determine the volume ratio of concrete and EPS particles in the elastic lightweight concrete layer according to the design requirements of road shock absorption and vibration isolation, and the volume ratio is 3:2 or 3:1 or 4:1; wherein, the concrete is according to According to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm;

2) Mix concrete and EPS particles according to the volume ratio determined in step 1), and use a vibrator or a vibrator to fully mix the concrete and EPS particles evenly; add polypropylene during the mixing process of elastic lightweight concrete Amide, the weight of polyacrylamide is controlled according to the weight of cement when concrete is mixed, specifically: when the volume ratio of concrete and EPS particles is 3:2, the weight of polyacrylamide is 1.1% of the weight of cement; the weight of concrete and EPS particles When the volume ratio is 3:1, the weight of polyacrylamide is 0.8-1.0% of the cement weight; when the volume ratio of concrete and EPS particles is 4:1, the weight of polyacrylamide is 0.6-0.8% of the cement weight;

3) Transport the uniformly mixed elastic lightweight concrete to the site for pouring to form an elastic lightweight concrete layer with a smooth surface.

Further, the elastic lightweight concrete layer has a thickness of 25-30 cm.

Further, the viscosity of polyacrylamide is greater than 50000mpa.S.

Beneficial effects: the subway shock-absorbing vibration-isolation elastic hybrid lightweight track bed control technology provided by the present invention can make the subway shock-absorbing vibration-isolation elastic hybrid light track bed more effectively reduce vibration and vibration isolation, because the function of EPS particles is to absorb the movement of subway trains The generated vibration waves and vibration energy, secondly, due to the large wave impedance difference between EPS particles and concrete, the transmission energy through the base layer of the mixed elastic lightweight ballast bed will be relatively small, so that the vibration energy of the subway is transmitted to the lining of the subway Or the energy on the segment is small; this can effectively block and reduce the energy of the train vibration from being transmitted to the lining structure of the subway, and then transmitted to the surrounding foundation soil by the lining structure, which will have a great impact on the buildings on the surface and the foundation of the subway. Additional vibration or cause secondary vibration, resulting in impact or even harm.

Description of drawings

Fig. 1 is a kind of structural representation of the present invention;

Fig. 2 is a process flow diagram of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, it is a subway shock-absorbing, vibration-isolating, elastic hybrid lightweight track bed, and how to effectively control its quality is the key.

The present invention mainly uses mixed concrete and ESP particles to form an elastic lightweight concrete layer 1 with a thickness of 25 to 30 cm; this elastic lightweight concrete layer 1 is arranged at the bottom of the subway track bed as the foundation track bed, and is compatible with the lining segments 4 of the subway. touch.

The difference in wave impedance between EPS particles and concrete is relatively large, so the transmitted energy will be relatively small, which will attenuate the transmitted vibration energy, and its energy attenuation can reach more than 20dB, which plays an obvious role in shock absorption and vibration isolation. This composite structure ballast bed not only meets the requirements of strength and long-term stability, but also has certain elasticity, and its effect of shock absorption and vibration isolation is obvious.

The elastic lightweight concrete layer 1 absorbs the vibration waves and vibration energy generated by the running of the subway locomotive, which can effectively block and reduce the transmission of the vibration energy of the locomotive to the lining structure of the subway, and from the lining structure to the surrounding rock and soil mass. Additional vibrations will be generated on the buildings and subway foundations on the surface, which will affect or even cause harm. The subway construction on soft soil foundations can reduce the cumulative deformation caused by locomotive vibration. As shown in Figure 1, the input vibration shock wave 2 forms an output vibration shock wave 3 after passing through the foundation ballast bed and the subway lining segment 4.

The metro shock-absorbing vibration-isolation elastic hybrid lightweight ballast bed control process specifically includes the following steps:

Embodiment one:

1. Determine the volume ratio of concrete and EPS particles in the mixed elastic lightweight ballast material according to the design requirements of road shock absorption and vibration isolation. The volume ratio of concrete and EPS particles is 3:2. The higher the design requirements for shock absorption and vibration isolation, the EPS The greater the particle content. Concrete is proportioned according to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm;

2. Mix the concrete and EPS particles according to the determined volume ratio, and use a vibrator or a vibrating rod to fully mix the concrete and EPS particles evenly; in order to prevent the vibration during the pouring of the elastic lightweight concrete layer 1 from causing EPS Particles float up and affect the strength and durability of elastic lightweight concrete 1. It is necessary to add polyacrylamide to elastic lightweight concrete 1. When the volume ratio of concrete and EPS particles is 3:2, the weight of polyacrylamide is 1.1 of the weight of cement %; After polyacrylamide is dissolved in water, it should be added slowly during the mixing of lightweight concrete;

3. Transport the uniformly mixed elastic lightweight concrete 1 to the site for pouring. Vibration must be uniform and orderly to make the surface of the elastic lightweight concrete layer 1 smooth, prolong the vibration time, prevent local accumulation of EPS particles, and ensure uniform strength .

Embodiment two:

1. Determine the volume ratio of concrete and EPS particles in the mixed elastic lightweight ballast material according to the design requirements of road shock absorption and vibration isolation. The volume ratio of concrete and EPS particles is 3:1. The higher the design requirements for shock absorption and vibration isolation, the EPS The greater the particle content. Concrete is proportioned according to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm;

2. Mix the concrete and EPS particles according to the determined volume ratio, and use a vibrator or a vibrating rod to fully mix the concrete and EPS particles evenly; in order to prevent the vibration during the pouring of the elastic lightweight concrete layer 1 from causing EPS The particles float up, affecting the strength and durability of the elastic lightweight concrete 1, and it is necessary to add polyacrylamide to the elastic lightweight concrete 1. When the volume ratio of concrete and EPS particles is 3:1, the weight of polyacrylamide is 0.8% of cement. After polyacrylamide is dissolved in water, it should be added slowly during the mixing of lightweight concrete;

3. Transport the uniformly mixed elastic lightweight concrete 1 to the site for pouring. Vibration must be uniform and orderly to make the surface of the elastic lightweight concrete layer 1 smooth, prolong the vibration time, prevent local accumulation of EPS particles, and ensure uniform strength .

Embodiment three

1. Determine the volume ratio of concrete and EPS particles in the mixed elastic lightweight ballast material according to the design requirements of road shock absorption and vibration isolation. The volume ratio of concrete and EPS particles is 3:1. The higher the design requirements for shock absorption and vibration isolation, the EPS The greater the particle content. Concrete is proportioned according to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm;

2. Mix the concrete and EPS particles according to the determined volume ratio, and use a vibrator or a vibrating rod to fully mix the concrete and EPS particles evenly; in order to prevent the vibration during the pouring of the elastic lightweight concrete layer 1 from causing EPS The particles float up, affecting the strength and durability of the elastic lightweight concrete 1, and it is necessary to add polyacrylamide to the elastic lightweight concrete 1. When the volume ratio of concrete and EPS particles is 3:1, the weight of polyacrylamide is 1.0% of cement; after polyacrylamide is dissolved in water, it should be added slowly during the mixing of lightweight concrete;

3. Transport the uniformly mixed elastic lightweight concrete 1 to the site for pouring. Vibration must be uniform and orderly to make the surface of the elastic lightweight concrete layer 1 smooth, prolong the vibration time, prevent local accumulation of EPS particles, and ensure uniform strength .

Embodiment four:

1. Determine the volume ratio of concrete and EPS particles in the mixed elastic lightweight ballast material according to the design requirements of road shock absorption and vibration isolation. The volume ratio of concrete and EPS particles is 4:1. Concrete is proportioned according to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm;

2. Mix the concrete and EPS particles according to the determined volume ratio, and use a vibrator or a vibrating rod to fully mix the concrete and EPS particles evenly; in order to prevent the vibration during the pouring of the elastic lightweight concrete layer 1 from causing EPS The particles float up, affecting the strength and durability of the elastic lightweight concrete 1, and it is necessary to add polyacrylamide to the elastic lightweight concrete 1. When the volume ratio of concrete and EPS particles is 4:1, the weight of polyacrylamide is 0.6% of cement. After polyacrylamide is dissolved in water, it should be added slowly during the mixing of lightweight concrete;

3. Transport the uniformly mixed elastic lightweight concrete 1 to the site for pouring. Vibration must be uniform and orderly to make the surface of the elastic lightweight concrete layer 1 smooth, prolong the vibration time, prevent local accumulation of EPS particles, and ensure uniform strength .

Embodiment five:

1. Determine the volume ratio of concrete and EPS particles in the mixed elastic lightweight ballast material according to the design requirements of road shock absorption and vibration isolation. The volume ratio of concrete and EPS particles is 4:1. Concrete is proportioned according to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm;

2. Mix the concrete and EPS particles according to the determined volume ratio, and use a vibrator or a vibrating rod to fully mix the concrete and EPS particles evenly; in order to prevent the vibration during the pouring of the elastic lightweight concrete layer 1 from causing EPS The particles float up, affecting the strength and durability of the elastic lightweight concrete 1, and it is necessary to add polyacrylamide to the elastic lightweight concrete 1. When the volume ratio of concrete and EPS particles is 4:1, the weight of polyacrylamide is 0.8% of cement; after dissolving polyacrylamide with appropriate amount of water, it should be added slowly during the mixing of lightweight concrete;

3. Transport the uniformly mixed elastic lightweight concrete 1 to the site for pouring. Vibration must be uniform and orderly to make the surface of the elastic lightweight concrete layer 1 smooth, prolong the vibration time, prevent local accumulation of EPS particles, and ensure uniform strength .

The larger the proportion of polyacrylamide, the smaller the floating amount of EPS particles, the more uniform the distribution, and the better the quality. However, the increase of the proportion of polyacrylamide will only cause the fluidity of the concrete to be slightly poorer. Properly prolonging the vibration time can solve this problem .

The amount of polyacrylamide has a certain correlation with the amount of EPS particles. As the amount of EPS particles increases, the amount of polyacrylamide also increases appropriately. Add the optimal amount of polyacrylamide: (1) when the volume ratio of concrete and EPS particles is 3:2, the weight of polyacrylamide is 1.1% of the cement weight; (2) the volume ratio of concrete and EPS particles is 3:1 (3) When the volume ratio of concrete and EPS particles is 4:1, the weight of polyacrylamide is 0.6-0.8% of the cement weight.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (2)

1. The metro shock-absorbing vibration-isolation elastic hybrid lightweight ballast bed control technology is characterized in that it includes the following steps: 1), determine the volume ratio of concrete and EPS particles in the elastic lightweight concrete layer according to the design requirements of shock absorption and vibration isolation along the subway line, the volume ratio is 3:2 or 3:1 or 4:1; wherein, the concrete According to the requirements of C35, the density of EPS particles is 12-15kg/m ³ , and the particle size of EPS particles is 1-2mm; 2) Mix concrete and EPS particles according to the volume ratio determined in step 1), and use a vibrator or a vibrator to fully mix the concrete and EPS particles evenly; add polypropylene during the mixing process of elastic lightweight concrete Amide, the weight of polyacrylamide is controlled according to the weight of cement when concrete is mixed, specifically: when the volume ratio of concrete and EPS particles is 3:2, the weight of polyacrylamide is 1.1% of the weight of cement; the weight of concrete and EPS particles When the volume ratio is 3:1, the weight of polyacrylamide is 0.8-1.0% of the cement weight; when the volume ratio of concrete and EPS particles is 4:1, the weight of polyacrylamide is 0.6-0.8% of the cement weight; 3) Transport the uniformly mixed elastic lightweight concrete to the site for pouring to form an elastic lightweight concrete layer with a smooth surface; The viscosity of polyacrylamide is greater than 50000mpa.S. 2. The shock-absorbing, vibration-isolating, elastic-mixed lightweight track bed control process for subways according to claim 1, characterized in that: the elastic lightweight concrete layer has a thickness of 25-30 cm.