CN116537268A - Periodic vibration reduction barrier for foundation pit of rail transit and construction method - Google Patents

Abstract

The invention discloses a foundation pit periodic vibration reduction barrier for rail transit and a construction method thereof, belonging to the technical field of vibration reduction barriers, and comprising a waterproof curtain, a support pile row, a separation layer, a filling soil layer and a post-pouring concrete layer; the support pile rows comprise support piles which are arranged at intervals; the separation layer is arranged between two adjacent support piles and forms a separation structure together with the support piles; the filling soil layer is arranged between the waterproof curtain and the separation structure; the post-cast concrete layer is arranged between two adjacent support piles and is positioned on the outer side of the separation layer. The invention improves on the basis of the existing foundation pit supporting structure, and fills the soil between the waterproof curtain and the supporting pile row by filling the concrete between the supporting piles to form a periodic wave barrier, thereby effectively reducing the environmental vibration caused by public transportation; simple structure, the construction of being convenient for has reduced the construction cost of damping barrier, and has realized the vibration damping effect of preferred, has good economic benefits and use value.

Description

Periodic vibration reduction barrier for foundation pit of rail transit and construction method

Technical Field

The invention belongs to the technical field of vibration reduction barriers, and particularly relates to a foundation pit periodic vibration reduction barrier for rail transit and a construction method.

Background

The environmental vibration caused by the rail transit operation can have adverse effect on surrounding buildings and crowds, and the adverse effect of the environmental vibration caused by the high-speed rail operation can be effectively reduced by adopting proper vibration reduction measures, so that the comfort level of the building structure is improved. TOD mode refers to a public transportation oriented development mode, typically centered on public transportation, with a radius of 400-800m, creating a center square or city center. TOD is characterized by a 'mixed use' integrating office, business, cultural, educational, living and the like, and coordinates contradiction of traffic jam and insufficient land generated in the city development process through land use and traffic policies. In this mode, people have tighter space-time intersections with public transportation, and are not well controlled by environmental vibrations caused by public transportation.

Vibration reduction measures can generally be divided into three categories: active vibration damping at the vibration source, vibration damping of the propagation path (vibration damping barrier), passive vibration damping of the vibration receiving body. Vibration-damping barriers are commonly used for low-frequency vibration-damping measures of high-speed railways, urban rail transit and the like. The vibration reduction barrier comprises measures such as empty ditches, filling ditches, wave resistance blocks (WIB), row piles, hole columns and the like. The depths of the empty trenches and the filling trenches have larger influence on the vibration reduction effect, but in practical engineering, the deep trenches have the problems of large excavation difficulty, high supporting cost and unstable action under the pressure of water and soil; in the row piles and the hole columns, the number of the pile rows has larger influence on the vibration reduction effect, in actual engineering, the pile spacing needs to be reduced as much as possible, the number of the pile rows is increased to improve the vibration reduction effect, the number of the piles is more, and the construction cost is greatly increased; in the wave choke damping method, the vibration damping effect is poor due to the self-vibration effect of the wave choke.

In summary, although the vibration-damping barrier technology has many applications in engineering, there are still problems of blindness in vibration-damping measure design, difficulty in vibration-damping barrier construction, poor vibration-damping effect, high construction cost, and the like.

Disclosure of Invention

The invention aims to provide a periodic vibration reduction barrier for a foundation pit of rail transit and a construction method thereof, which are used for solving the problems of difficult construction, poor vibration reduction effect and high construction cost of the vibration reduction barrier in the background technology.

In order to achieve the above purpose, the present invention provides the following technical solutions:

a foundation pit periodic vibration reduction barrier for rail transit comprises a waterproof curtain, a support pile row, a separation layer, a filling soil layer and a post-pouring concrete layer; the support pile rows comprise support piles which are arranged at intervals; the separation layer is arranged between two adjacent support piles and forms a separation structure together with the support piles; the filling soil layer is arranged between the waterproof curtain and the separation structure; the post-cast concrete layer is arranged between two adjacent support piles and is positioned on the outer side of the separation layer.

Further, the waterproof curtain and the support pile row are of concrete structures.

Further, the separation layer comprises a steel plate net, transverse press bars and a concrete layer; the two sides of the steel plate net are aligned with the supporting piles; the transverse pressing ribs are fixedly arranged on the steel plate net, and both ends of the transverse pressing ribs are inserted into the supporting piles and are welded with the steel bars in the supporting piles; the concrete layer is sprayed on the steel plate net.

Further, the outer side surface of the post-cast concrete layer far away from the waterproof curtain is flush with the outer end of the support pile, and transverse ribs are arranged at intervals inside the post-cast concrete layer.

Further, both ends of the transverse ribs are inserted into the support piles and are welded with the steel bars in the support piles.

Further, the supporting piles are provided with anchor bars corresponding to the transverse bars, and the transverse bars are fixedly connected with the anchor bars.

Further, an outer side template is arranged on the outer side of the post-cast concrete layer, and the outer side template is fixedly connected with the support pile.

Further, the effective thickness of the waterproof curtain is the same as the equivalent thickness of the post-cast concrete layer, the support pile row and the separation layer after being combined.

Further, the waterproof curtain top surface, the support pile row top surface, the filling soil layer top surface, the post-cast concrete layer top surface and the separation layer top surface are all flush.

A construction method of a foundation pit periodic vibration reduction barrier for rail transit comprises the following steps:

step one, supporting pile row construction and waterproof curtain construction are sequentially carried out;

step two, constructing a separation layer;

step three, constructing a post-pouring concrete layer, namely binding transverse ribs, fixedly connecting two ends of the transverse ribs with the support piles, erecting an outer side template, connecting the outer side template with the support piles, pouring concrete, and removing the outer side template after concrete molding;

and step four, backfilling the residual foundation pit fertilizer grooves to complete the integral construction of the periodic vibration reduction barrier.

The invention has the following beneficial effects:

1. according to the foundation pit periodic vibration reduction barrier for the rail transit and the construction method, improvement is carried out on the basis of an existing foundation pit supporting structure, concrete is filled between supporting piles, soil is filled between the waterproof curtain and supporting pile rows, a periodic wave barrier is formed, and environmental vibration caused by public transit is effectively reduced.

2. The foundation pit periodic vibration reduction barrier for the rail transit and the construction method thereof have the advantages of simple structure, convenience in construction, reduction in construction cost of the vibration reduction barrier, realization of a better vibration reduction effect, and good economic benefit and use value.

3. According to the foundation pit periodic vibration reduction barrier for the rail transit and the construction method, provided by the invention, the effective vibration reduction frequency range of the foundation pit periodic vibration reduction barrier can be quantified by utilizing the periodic structure theory, so that the accurate control of a main frequency band is realized; the blindness problem of the traditional wave barrier path vibration reduction measure design is effectively solved.

Drawings

FIG. 1 is a schematic view of the overall structure of a vibration reduction barrier according to the present invention;

FIG. 2 is a cross-sectional view of the view A-A of FIG. 1 in accordance with the present invention;

FIG. 3 is a schematic layout of spacer and support piles according to the present invention;

fig. 4 is a schematic diagram of a connection between a post-cast concrete layer and a support pile according to the present invention.

In the figure: 1-waterproof curtain, 2-support pile row, 3-separation layer, 4-filling soil layer and 5-post-pouring concrete layer.

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.

As shown in fig. 1 and 2, the foundation pit periodic vibration reduction barrier for rail transit provided by the invention comprises a waterproof curtain 1, a support pile row 2, a separation layer 3, a filling soil layer 4 and a post-pouring concrete layer 5; the support pile row 2 comprises support piles which are arranged at intervals; the separation layer 3 is arranged between two adjacent support piles, and the support piles and the separation layer 3 form a separation structure together; the filling soil layer 4 is arranged between the waterproof curtain 1 and the separation structure; the post-cast concrete layer 5 is arranged between two adjacent support piles and is positioned at the outer side of the separation layer 3 far away from the waterproof curtain 1; the waterproof curtain 1, the support pile row 2, the filling soil layer 4, the post-cast concrete layer 5 and the separation layer 3 form a foundation pit periodic vibration reduction barrier together.

The waterproof curtain 1 and the support pile row 2 are both of concrete structures. One side of the waterproof curtain 1 is the soil body outside the foundation pit, the pile diameter is 0.85m, and the minimum thickness is 0.6m; the pile diameter of the support pile is 1m, and the center distance of the piles is determined by the design requirement of the support; the clearance between the waterproof curtain 1 and the support pile is 0.6m. The top of the support pile row 2 is provided with a crown beam, and is connected with a stable stratum outside the foundation pit through an anchor cable.

The periodic vibration reduction barrier consists of two periodic units, wherein the support pile row 2, the separation layer 3, the filling soil layer 4 and the post-pouring concrete layer 5 are one periodic unit, and the waterproof curtain 1 and the soil body outside the foundation pit (the same thickness as the filling soil layer) are the other periodic units, so that the effective thickness of the waterproof curtain 1 is the same as the equivalent thickness of the post-pouring concrete layer 5, the support pile row 2 and the separation layer 3 after being combined, and the thickness values of all the structures are analyzed and designed according to vibration characteristics. In general, the thickness of the post-cast concrete layer 5 is set to be half of the diameter of the support pile, namely, the equivalent thickness of the support pile is ensured to be equivalent to the effective thickness of the waterproof curtain 1.

The top surfaces of the waterproof curtain 1, the supporting pile row 2, the filling soil layer 4, the post-pouring concrete layer 5 and the separation layer 3 are all flush.

As shown in fig. 3, the separation layer 3 comprises a steel plate net, transverse press bars and a concrete layer, wherein two sides of the steel plate net are aligned with the supporting piles; the transverse pressing ribs are fixedly arranged on the steel plate net, and both ends of the transverse pressing ribs are inserted into the supporting piles and are welded with the steel bars in the supporting piles so as to ensure the fixation of the steel plate net; the concrete layer is sprayed on the steel plate net. Preferably, the thickness of the separation layer 3 is 8cm. The spacer layer 3 simultaneously serves as an inner formwork for the post-cast concrete layer 5.

The outer side surface of the post-cast concrete layer 5 far away from the waterproof curtain 1 is flush with the outer end of the support pile, and transverse ribs are arranged at intervals inside the post-cast concrete layer. As a preferable mode, two ends of the transverse rib are inserted into the support pile and are welded with the steel bars in the support pile. As another preferable mode, as shown in fig. 4, the supporting piles are provided with anchor bars corresponding to the transverse bars, and the transverse bars are fixedly connected with the anchor bars. More preferably, the thickness of the post-cast concrete layer 5 is the same as the radius of the support pile, the top surface of the post-cast concrete layer is level with the top surface of the support pile, and the overall height of the post-cast concrete layer is 5m. The outside of post-cast concrete layer 5 sets up outside template for its pouring shaping, outside template links firmly with the support stake, and the outside of outside template can adopt the bracing to consolidate.

A construction method of a foundation pit periodic vibration reduction barrier for rail transit comprises the following steps:

sequentially constructing the support pile row 2 and the waterproof curtain 1, wherein the waterproof curtain 1 adopts an adaptive deep mixing pile construction mode according to geological conditions to form a waterproof curtain 1 with the effective thickness of 0.6m, so that the waterproof curtain 1 at least reaches a ground continuous wall effect within the range of 5m below the ground, the support pile row 2 is firstly manufactured, the waterproof curtain 1 is firstly manufactured, the range of the waterproof curtain 1 is reduced, the influence of soil disturbance of the support pile construction is avoided, and the waterproof and vibration reduction effects are ensured;

step two, constructing a separation layer 3, namely firstly, drilling small holes of ∅ mm and not less than 100mm in depth on pile bodies at two sides with an electric drill along with the construction progress of a foundation pit, then inserting two ends of transverse pressing ribs of the separation layer 3 into the small holes, welding the transverse pressing ribs with the steel bars in the piles, and spraying a concrete layer until the foundation pit is excavated to a designed elevation;

thirdly, post-pouring concrete layer 5 construction, namely backfilling a foundation pit fertilizer groove to a position 5m below the natural ground, binding transverse ribs, fixedly connecting two ends of the transverse ribs with supporting piles, erecting an outer side template, connecting the outer side template with the supporting piles, pouring concrete, and removing the outer side template after concrete molding;

and step four, backfilling the foundation pit fertilizer grooves with the depth of 5m, and completing the integral construction of the periodic vibration reduction barrier.

Working principle: a periodic vibration reduction barrier is one of periodic structures, and refers to a structure formed by periodically repeating a typical unit (or unit cell) composed of two or more materials in space. The periodic structure has a remarkable feature that elastic waves of some specific frequencies cannot propagate in the periodic structure. In a finite periodic structure, waves within the band gap range are similarly suppressed or attenuated during propagation, and the band gap of the corresponding periodic structure is referred to as the "attenuation domain". The invention utilizes the waterproof curtain 1, the filling soil layer 4, the post-pouring concrete layer 5 and the support piles to form a periodic vibration reduction barrier together, namely a limited periodic structure, and has good vibration reduction effect on vibration in a specific frequency band.

Finally, it should be noted that: the foregoing description is only illustrative of the preferred embodiments of the present invention, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements or changes may be made without departing from the spirit and principles of the present invention.

Claims (10)

1. The foundation pit periodic vibration reduction barrier for the rail transit is characterized by comprising a waterproof curtain (1), a support pile row (2), a separation layer (3), a filling soil layer (4) and a post-pouring concrete layer (5); the support pile row (2) comprises support piles which are arranged at intervals; the separation layer (3) is arranged between two adjacent support piles and forms a separation structure together with the support piles; the filling soil layer (4) is arranged between the waterproof curtain (1) and the separation structure; the post-cast concrete layer (5) is arranged between two adjacent support piles and is positioned on the outer side of the separation layer (3).

2. The foundation pit periodic vibration reduction barrier for rail transit according to claim 1, wherein the waterproof curtain (1) and the supporting pile row (2) are both of a concrete structure.

3. A foundation pit periodic vibration reduction barrier for rail transit according to claim 1, wherein the separation layer (3) comprises a steel sheet mesh, transverse tendons and concrete layers; the two sides of the steel plate net are aligned with the supporting piles; the transverse pressing ribs are fixedly arranged on the steel plate net, and both ends of the transverse pressing ribs are inserted into the supporting piles and are welded with the steel bars in the supporting piles; the concrete layer is sprayed on the steel plate net.

4. The foundation pit periodic vibration reduction barrier for rail transit according to claim 1, wherein the outer side surface of the post-cast concrete layer (5) far away from the waterproof curtain (1) is flush with the outer end of the support pile, and transverse ribs are arranged at intervals inside the post-cast concrete layer.

5. The periodic vibration reduction barrier for a foundation pit for rail transit according to claim 4, wherein both ends of the transverse ribs are inserted into the supporting piles and are welded with the reinforcing steel bars in the supporting piles.

6. The periodic vibration reduction barrier for a foundation pit for rail transit according to claim 4, wherein the supporting piles are provided with anchor bars corresponding to the transverse bars, and the transverse bars are fixedly connected with the anchor bars.

7. A foundation pit periodic vibration reduction barrier for rail transit according to claim 1, wherein an outer form is provided on the outer side of the post-cast concrete layer (5), said outer form being fixedly connected to a support pile.

8. The foundation pit periodic vibration reduction barrier for rail transit according to claim 1, wherein the effective thickness of the waterproof curtain (1) is the same as the equivalent thickness of the post-cast concrete layer (5), the support pile row (2) and the separation layer (3) after being combined.

9. The foundation pit periodic vibration reduction barrier for rail transit according to claim 1, wherein the top surface of the waterproof curtain (1), the top surface of the support pile row (2), the top surface of the filling soil layer (4), the top surface of the post-cast concrete layer (5) and the top surface of the separation layer (3) are all flush.

10. The construction method of a foundation pit periodic vibration reduction barrier for rail transit according to any one of claims 1 to 9, comprising the steps of:

step one, sequentially constructing a support pile row (2) and a waterproof curtain (1);

step two, constructing a separation layer (3);

step three, constructing a post-pouring concrete layer (5), firstly binding transverse ribs, fixedly connecting two ends of the transverse ribs with the support piles, then erecting an outer side template, connecting the outer side template with the support piles, pouring concrete, and removing the outer side template after concrete molding;

and step four, backfilling the residual foundation pit fertilizer grooves to complete the integral construction of the periodic vibration reduction barrier.