Vibration isolation structure and vibration isolation method for super-large-section shallow-buried excavation tunnel

Abstract

The vibration isolation structure comprises a vibration isolation body and vibration isolation layers arranged on the two sides of the vibration isolation body, each vibration isolation layer is of a porous structure, the vibration isolation layers are arranged between the vibration isolation body and surrounding rock, and the thickness of each vibration isolation layer ranges from 5 cm to 10 cm. According to the design, when fluctuation enters the porous structure, pores in the vibration isolation layer can generate multiple scattering and reflection on incident waves, the scattering and reflection processes prolong the propagation path of the fluctuation, increase the interaction time between the fluctuation and the interior of the material, guide the fluctuation energy to be dissipated in the vibration isolation structure, and further reduce the impact on the surrounding environment; by absorbing and dispersing fluctuation energy, the vibration isolation structure remarkably reduces transmission of vibration waves to surrounding buildings, and therefore potential damage to the buildings is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of shallow buried dark excavation construction of underground structures, and more specifically to a vibration isolation method for a shallow buried dark excavation tunnel with an extra-large cross-section. Background Art

[0002] The development of urban underground space often has a certain impact on the surrounding environment. During the blasting and excavation of underground space, the blasting wave is easy to spread from the detonation point to the surrounding area through the rock and soil as the medium. The blasting wave energy is relatively high and is difficult to attenuate in the dense rock and soil. When it spreads to the surrounding buildings, it is easy to spread to the building structure through structures such as pile foundations, causing large building vibrations and poor comfort for personnel. In severe cases, it will also cause irreversible instability and damage to surrounding buildings.

[0003] In response to the above problems, vibration isolation treatment is often carried out by constructing piles and underground continuous walls. The main principle is to reflect the vibration through the difference in physical parameters of reinforced concrete and rock and soil, such as density and strength, and absorb a small amount of vibration energy. However, when the difference in physical parameters between the concrete structure and the surrounding rock is small and the degree of fit between the two is strong, the above method is extremely limited in absorbing the blasting vibration. When the blasting vibration energy is transmitted to the surrounding buildings, the blasting vibration causes the building to vibrate in the horizontal and vertical directions. Once the blasting vibration frequency is equal to or close to the natural frequency of the building, it will cause serious consequences. When the local deformation of the building exceeds the safety value, it will affect the performance and even the safety of the building, such as cracks in the wall, vibration of doors and windows, etc.; secondly, multiple blasting will also cause fatigue damage to buildings with low strength, and the safety factor will be reduced. If there is a concrete structure that has just been poured near the blasting area, the blasting vibration will have a greater impact on it and reduce its strength. In addition, if the foundation conditions of the building are not good, multiple blasting may cause liquefaction of the building foundation and reduce the bearing capacity of the foundation. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a vibration isolation method for a shallow-buried dark-excavated tunnel with an extra-large cross-section, so as to solve the problem that the surrounding buildings are easily damaged during the blasting and excavation process of the underground space.

[0005] The technical solution of the present invention is as follows: A vibration isolation structure for a shallow buried tunnel with an extra-large cross-section, comprising a vibration isolation main body and a vibration isolation layer arranged on both sides of the vibration isolation main body, wherein the vibration isolation layer is a porous structure, and the vibration isolation layer is arranged between the vibration isolation main body and the surrounding rock, and the thickness of the vibration isolation layer is 5 cm to 10 cm.

[0006] Furthermore, the vibration isolation body is a reinforced concrete structure.

[0007] Furthermore, the vibration isolation layer includes a microporous foam rubber layer and a porous rubber layer, one side of the microporous foam rubber layer is in contact with the surrounding rock, and the other side of the microporous foam rubber layer is in contact with the porous rubber layer, a plurality of through holes are arranged in the porous rubber layer, and the plurality of through holes are arranged at equal intervals, and a plurality of notches are arranged on a side of the porous rubber layer away from the microporous foam rubber layer, and the plurality of notches are arranged at equal intervals, and the plurality of notches are staggered with the plurality of through holes.

[0008] Furthermore, the vibration isolation body is a foam concrete vibration isolation layer.

[0009] In addition, the present invention also provides a vibration isolation method for a large-section shallow-buried dark-excavated tunnel, which is applied to the vibration isolation structure of the large-section shallow-buried dark-excavated tunnel, and comprises the following steps:

[0010] S1. Slotting is performed at the designed position of the ground-connected wall to dig out the slot body;

[0011] S2, performing formwork support operations in the trough body, and after the formwork support is completed, setting a steel cage inside the formwork to form a complete steel skeleton;

[0012] S3, pouring concrete in the formwork to form a vibration isolation body, then removing the formwork, and arranging vibration isolation layers on both sides of the vibration isolation body to construct a vibration isolation structure;

[0013] S4. A plurality of embedded vibration exciters are arranged on a side of the vibration isolation structure facing away from the blasting vibration source, and the plurality of embedded vibration exciters are respectively arranged at four equally divided points in the depth direction of the vibration isolation structure.

[0014] Furthermore, before step S1, well point dewatering is first performed near the ground-connected wall, and the distance between the dewatering well and the ground-connected wall is 5m to 10m.

[0015] Furthermore, in step S1, grooving is performed at the designed position of the ground-anchored wall to excavate the groove body, specifically: an excavator is used in conjunction with a grooving bucket to groove at the designed position of the ground-anchored wall, and the groove body is excavated layer by layer in a layered excavation manner, and the single excavation depth is controlled between 0.5m and 1m.

[0016] Furthermore, in step S3, concrete is poured in the formwork to form the vibration isolation body, the formwork is then removed, and the vibration isolation layer having a thickness of 5 cm to 10 cm is provided on both sides of the vibration isolation body.

[0017] Furthermore, the vibration isolation layer is formed by compositely vulcanizing microporous foam rubber and porous rubber through integral vulcanization molding.

[0018] The present invention according to the above scheme has the following beneficial effects:

[0019] (1) The present invention provides a vibration isolation structure for a shallow-buried tunnel with a large cross-section, comprising a vibration isolation body and vibration isolation layers arranged on both sides of the vibration isolation body. The vibration isolation layer is a porous structure and is arranged between the vibration isolation body and the surrounding rock. The thickness of the vibration isolation layer is 5 cm to 10 cm. Such a design, on the basis of traditional underground continuous walls and pile rows, adds a vibration isolation body, and sets a vibration isolation layer with a porous structure on both sides of the vibration isolation body. The vibration isolation layer adopts a porous structure design, which can convert the wave energy into heat energy or other forms of energy through the friction and damping effect of the pores during the propagation of blasting waves, thereby effectively reducing the transmission of waves. Secondly, such a design can also play a regulating role in the reflection and refraction of waves. When the wave enters the porous structure, the pores in the vibration isolation layer will produce multiple scattering and reflection of the incident wave. These scattering and reflection processes extend the propagation path of the wave, increase the interaction time between the wave and the inside of the material, guide the wave energy to dissipate in the vibration isolation structure, and further reduce the impact on the surrounding environment. By absorbing and dispersing the wave energy, the vibration isolation structure significantly reduces the transmission of vibration waves to surrounding buildings, thereby reducing potential damage to buildings.

[0020] (2) The vibration isolation structure of a shallow-buried tunnel with a large cross-section provided by the present invention has a vibration isolation layer with a thickness of 5 cm to 10 cm. This design ensures sufficient energy absorption effect while avoiding the increase of construction difficulty and cost due to the excessive thickness of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 is a schematic diagram of a vibration isolation structure in an embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of a vibration isolation layer in an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the propagation path of the explosion wave propagation line;

[0025] Figure 4 Schematic diagram of secondary peak clipping of vibration fluctuations by an embedded vibrator.

[0026] In the figure, 1, vibration isolation body; 2, vibration isolation layer; 21, microporous foam rubber layer; 22, porous rubber layer; 221, through hole; 222, notch; 3, blasting vibration source; 4, building; 5, embedded exciter. DETAILED DESCRIPTION

[0027] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0028] In order to better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0029] See also Figure 1 to Figure 4 As shown, in a preferred embodiment of the present invention, a vibration isolation structure for a shallow buried tunnel with a particularly large cross-section is provided, comprising a vibration isolation body 1 and vibration isolation layers 2 arranged on both sides of the vibration isolation body 1, the vibration isolation layer 2 being a porous structure, the vibration isolation layer 2 being arranged between the vibration isolation body 1 and the surrounding rock, and the thickness of the vibration isolation layer 2 being 5 cm to 10 cm.

[0030] In this design, on the basis of the traditional underground continuous wall and pile row, an isolation body 1 is added, and a vibration isolation layer 2 with a porous structure is arranged on both sides of the isolation body 1. The vibration isolation layer 2 adopts a porous structure design, which can convert the wave energy into heat energy or other forms of energy through the friction and damping effect of the pores during the propagation of the blasting wave, thereby effectively reducing the transmission of the wave. Secondly, this design can also play a regulating role in the wave reflection and refraction process. When the wave enters the porous structure, the pores in the vibration isolation layer 2 will produce multiple scattering and reflection of the incident wave. These scattering and reflection processes extend the propagation path of the wave, increase the interaction time between the wave and the inside of the material, guide the wave energy to dissipate in the vibration isolation structure, and further reduce the impact on the surrounding environment. By absorbing and dispersing the wave energy, the vibration isolation structure significantly reduces the transmission of vibration waves to the surrounding buildings 4, thereby reducing the potential damage to the buildings 4.

[0031] It is worth mentioning that the thickness of the vibration isolation layer 2 is 5 cm to 10 cm. This design not only ensures sufficient energy absorption effect, but also avoids the structure being too thick and increasing the construction difficulty and cost.

[0032] In this embodiment, the vibration isolation body 1 is a reinforced concrete structure. More specifically, the vibration isolation body 1 is a foam concrete vibration isolation layer 2 .

[0033] Among them, the vibration isolation body 1 in this embodiment is a foam concrete vibration isolation layer 2. Compared with the surrounding rock and lining, the wave impedance of foam concrete is lower. When the stress wave generated by the penetration and explosion of the precision-guided deep-drilling weapon propagates to the vibration isolation structure with a large degree of wave impedance mismatch, multiple reflections and transmission phenomena will occur in the vibration isolation structure until equilibrium is reached. This process can effectively weaken the effect of stress waves on existing structures. Under the action of external loads, the large number of pores inside the foam concrete diffract the shock wave, weakening the pressure effect of the shock wave on the existing structure and reducing the damage of the shock wave to the existing structure.

[0034] In this embodiment, the vibration isolation layer 2 includes a microporous foam rubber layer 21 and a porous rubber layer 22. One side of the microporous foam rubber layer 21 is in contact with the surrounding rock. The microporous foam rubber layer 21 has good shock absorption performance due to its microporous structure. During the blasting and excavation process, the vibration energy generated is first absorbed and dispersed by the microporous foam rubber layer 21, effectively reducing the propagation intensity of the vibration wave to the surrounding environment; the other side of the microporous foam rubber layer 21 is in contact with the porous rubber layer 22, and a plurality of through holes 221 are arranged in the porous rubber layer 22, and the plurality of through holes 221 are arranged at equal intervals. A plurality of notches 222 are arranged on the side of the porous rubber layer 22 away from the microporous foam rubber layer 21, and the plurality of notches 222 are arranged at equal intervals, and the plurality of notches 222 are staggered with the plurality of through holes 221.

[0035] Specifically, the multiple through holes 221 in the porous rubber layer 22 are arranged at equal intervals. This layout ensures that the shock wave can be evenly absorbed and dispersed during the propagation process. The equally spaced through holes 221 reduce the focusing effect of the shock wave inside the material, thereby reducing the concentration and amplification of the vibration energy. Secondly, a plurality of equally spaced notches 222 are arranged on the side of the porous rubber layer away from the microporous foam rubber layer 21. Each notch 222 is staggered with each through hole 221. The staggered notches 222 and through holes 221 avoid the resonance effect of the shock wave inside the material, further enhancing the vibration isolation effect.

[0036] In addition, an embodiment of the present invention further provides a vibration isolation method for a large-section shallow-buried dark-excavated tunnel, which is applied to the vibration isolation structure of the large-section shallow-buried dark-excavated tunnel described above, and includes the following steps:

[0037] S1. Slotting is performed at the designed position of the ground-connected wall to dig out the slot body;

[0038] Specifically, in step S1, a slotting process is performed at the designed position of the ground-connected wall to dig out the slot body, specifically: an excavator is used with a slotting bucket to dig out the slot at the designed position of the ground-connected wall, and the slot body is dug out layer by layer in a layered excavation manner, and the single excavation depth is controlled between 0.5m and 1m. Among them, the single excavation depth is controlled between 0.5m and 1m, which can reduce the instability of the excavator during the excavation process and reduce the risk of side wall collapse caused by excessive excavation depth, thereby improving construction safety. Secondly, reasonable control of the excavation depth can reduce the disturbance to the surrounding soil, reduce the impact on surrounding buildings 4 and underground pipelines, and reduce environmental problems that may be caused during the construction process.

[0039] The layered excavation method can ensure that each layer of the trough structure has enough time to stabilize before the next layer is excavated, reducing structural deformation or damage caused by excessive excavation speed.

[0040] S2. Perform formwork support operations in the trough body. After the formwork support is completed, a steel cage is set inside the formwork to form a complete steel skeleton;

[0041] S3, pouring concrete in the formwork to form a vibration isolation body 1, then removing the formwork, and setting vibration isolation layers 2 on both sides of the vibration isolation body 1 to construct a vibration isolation structure;

[0042] In step S3 , concrete is poured in the formwork to form the vibration isolation body 1 , the formwork is then removed, and a vibration isolation layer 2 with a thickness of 5 cm to 10 cm is provided on both sides of the vibration isolation body 1 .

[0043] In this embodiment, the thickness of the vibration isolation layer 2 is preferably 10 cm. The inventors found that after the thickness of the vibration isolation layer 2 reaches 10 cm, continuing to increase the thickness of the vibration isolation layer 2 cannot effectively reduce the pressure and stress peaks, because the vibration isolation layer 2 mainly plays an energy-consuming and vibration-reducing role through plastic deformation. When the dynamic load remains unchanged, the deformation degree and dissipated energy of the vibration isolation layer 2 of different thicknesses are similar. After the thickness of the vibration isolation layer 2 exceeds 10 cm, the reduction in the pressure and stress peaks decreases. Considering the construction difficulty and cost economy, the optimal thickness of the vibration isolation layer 2 is 10 cm.

[0044] S4. A plurality of embedded vibration exciters 5 are arranged on the side of the vibration isolation structure facing away from the blasting vibration source 3, and the plurality of embedded vibration exciters 5 are respectively arranged at four equally divided points in the depth direction of the vibration isolation structure. With such a design, the embedded vibration exciters 5 can generate reverse vibration waves that interfere with the vibration waves passing through the vibration isolation structure, thereby achieving secondary peak clipping of the vibration fluctuations. Such interference effect can significantly reduce the amplitude of the vibration waves, thereby reducing the impact of the vibration on surrounding buildings.

[0045] Specifically, by designing a vibration isolation structure and combining the vibration isolation structure with an embedded vibration exciter 5 arranged on the outside of the vibration isolation structure, the vibration fluctuations passing through the vibration isolation structure are secondary peak-cut by the embedded vibration exciter 5, thereby reducing the adverse effects of vibration fluctuations on surrounding buildings during shallow buried tunnel blasting construction in urban spaces.

[0046] In this embodiment, a plurality of embedded vibrators 5 are arranged at four equally divided points in the depth direction of the vibration isolation structure. This arrangement can ensure that the reverse vibration waves generated by the embedded vibrators 5 can evenly cover the depth range of the entire vibration isolation structure, thereby achieving comprehensive peak clipping of the vibration fluctuations. In addition, the selection of the four equally divided points also takes into account the propagation characteristics of the vibration waves in the vibration isolation structure. In the depth direction, the vibration waves will gradually attenuate due to the damping of the structure and the absorption of the material. By setting the vibrators at four equally divided points, it can be ensured that there are sufficient reverse vibration waves at each depth level to interfere with the original vibration waves, thereby maximizing the peak clipping effect.

[0047] In this embodiment, before step S1, well point dewatering is first performed near the ground-connected wall. The distance between the dewatering well and the ground-connected wall is 5m to 10m, which can effectively lower the groundwater level and avoid adverse effects on the construction of the ground-connected wall.

[0048] In this embodiment, the vibration isolation layer 2 is formed by integrally vulcanizing and compounding microporous foam rubber and porous rubber.

[0049] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

[0050] The above is an exemplary description of the present invention in conjunction with the accompanying drawings. It is obvious that the implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A vibration isolation structure for a shallow buried dark-excavated tunnel with a large cross-section, characterized in that: include: A vibration isolation body and vibration isolation layers arranged on both sides of the vibration isolation body, wherein the vibration isolation layer is a porous structure, the vibration isolation layer is arranged between the vibration isolation body and the surrounding rock, and the thickness of the vibration isolation layer is 5cm-10cm.

2. The vibration isolation structure of a shallow-buried tunnel with a large cross-section as claimed in claim 1, characterized in that: The vibration isolation body is a reinforced concrete structure.

3. The vibration isolation structure of a shallow-buried tunnel with a large cross-section as claimed in claim 1, characterized in that: The vibration isolation layer includes a microporous foam rubber layer and a porous rubber layer, one side of the microporous foam rubber layer is in contact with the surrounding rock, and the other side of the microporous foam rubber layer is in contact with the porous rubber layer, a plurality of through holes are arranged in the porous rubber layer, and the plurality of through holes are arranged at equal intervals, and a plurality of notches are arranged on a side of the porous rubber layer away from the microporous foam rubber layer, and the plurality of notches are arranged at equal intervals, and the plurality of notches are staggered with the plurality of through holes.

4. The vibration isolation structure of a shallow-buried tunnel with a large cross-section as claimed in claim 1, characterized in that: The vibration isolation body is a foam concrete vibration isolation layer.

5. A vibration isolation method for a large-section shallow-buried dark-excavated tunnel, applied to the vibration isolation structure for a large-section shallow-buried dark-excavated tunnel as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Slotting is performed at the designed position of the ground-connected wall to dig out the slot body; S2, performing formwork support operations in the trough body, and after the formwork support is completed, setting a steel cage inside the formwork to form a complete steel skeleton; S3. pouring concrete in the formwork to form a vibration isolation body, then removing the formwork, and arranging vibration isolation layers on both sides of the vibration isolation body to construct a vibration isolation structure.

6. A vibration isolation method for a shallow-buried tunnel with a large cross-section as claimed in claim 5, characterized in that: Also includes: S4. A plurality of embedded vibration exciters are arranged on a side of the vibration isolation structure facing away from the blasting vibration source, and the plurality of embedded vibration exciters are respectively arranged at four equally divided points in the depth direction of the vibration isolation structure.

7. A vibration isolation method for a shallow-buried tunnel with a large cross-section as claimed in claim 5, characterized in that: Before step S1, firstly perform well point dewatering near the ground-connected wall, and the distance between the dewatering well and the ground-connected wall is 5m~10m.

8. The vibration isolation method for a shallow-buried tunnel with a large cross-section as claimed in claim 5, characterized in that: In step S1, slotting is performed at the designed position of the ground-anchored wall to excavate the slot body. Specifically, an excavator is used with a slotting bucket to slot at the designed position of the ground-anchored wall, and the slot body is excavated layer by layer using a layered excavation method. The single excavation depth is controlled between 0.5m and 1m.

9. A vibration isolation method for a shallow-buried tunnel with a large cross-section as claimed in claim 5, characterized in that: In step S3, concrete is poured into the formwork to form the vibration isolation body, the formwork is then removed, and the vibration isolation layer having a thickness of 5 cm to 10 cm is provided on both sides of the vibration isolation body.

10. A vibration isolation method for a shallow-buried tunnel with a large cross-section as claimed in claim 9, characterized in that: The vibration isolation layer is formed by integrally vulcanizing and compounding microporous foam rubber and porous rubber.

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