Bridge group pile foundation shallow hole blasting vibration reduction structure and method based on vibration reduction holes
阅读说明：本技术 基于减振孔的桥梁群桩基础浅眼***减振结构及方法 (Bridge group pile foundation shallow hole blasting vibration reduction structure and method based on vibration reduction holes ) 是由 龙立敦 王朝国 李少方 陈元忠 张凯 周旭 林文凯 于 2020-07-01 设计创作，主要内容包括：本发明公开了一种基于减振孔的桥梁群桩基础浅眼爆破减振结构及方法,其特征在于,包括掏槽眼(1),在掏槽眼(1)外侧设有周边眼(3),周边眼(3)外侧间距0.08-0.12m的位置设置减振孔(2)。基于隔振孔的桥梁群桩基础施工浅眼爆破减振结构及方法同时实现了高效减振与高效爆破。在实际工程中,结合成本分析,在被保护构筑物仅位于一个方向时,采用隔振孔措施每爆破循环仅增加成本425.6元,能够避免相邻桩基出现护壁或新浇桩身裂缝的安全隐患和质量问题,最终实现工期和施工间接成本的极大节约。(The invention discloses a vibration reduction hole-based shallow hole blasting vibration reduction structure and method for a bridge pile group foundation, which are characterized by comprising an undercut hole (1), wherein peripheral holes (3) are arranged on the outer side of the undercut hole (1), and vibration reduction holes (2) are arranged at positions with the outer side distance of 0.08-0.12m between the peripheral holes (3). The shallow hole blasting vibration reduction structure and method for bridge group pile foundation construction based on the vibration isolation holes simultaneously realize efficient vibration reduction and efficient blasting. In actual engineering, the method combines the analysis, when the protected structure is only positioned in one direction, the cost is only increased by 425.6 yuan per blasting circulation by adopting a vibration isolation hole measure, the potential safety hazard and the quality problem of cracks of a retaining wall or a newly cast pile body of an adjacent pile foundation can be avoided, and the construction period and the construction indirect cost are greatly saved.)
1. The shallow hole blasting vibration reduction structure based on the vibration reduction holes for the bridge pile group foundation is characterized by comprising the cut holes (1), wherein peripheral holes (3) are formed in the outer sides of the cut holes (1), and the vibration reduction holes (2) are formed in the positions, with the distance of 0.08-0.12m, of the outer sides of the peripheral holes (3).
2. The shallow hole blasting vibration reduction structure for the bridge pile group foundation based on the vibration reduction holes as claimed in claim 1, wherein the distance between the vibration reduction holes (2) and the peripheral holes (3) is 0.09-0.11 m.
3. The bridge pile group foundation shallow hole blasting vibration attenuation structure based on the vibration attenuation holes according to claim 1, wherein the vibration attenuation holes (2) are more than 2 and are arranged in an arc shape, and the circle center of the arc shape is the same as that of the blast holes (1) and the peripheral holes (3).
4. The shallow hole blasting vibration reduction structure for bridge pile group foundation based on vibration reduction holes according to claim 3, wherein the distance between the vibration reduction holes (2) is 0.2-0.3 m.
5. The shallow hole blasting vibration reduction structure for the bridge group pile foundation based on the vibration reduction holes as claimed in claim 4, wherein the arc angle of the vibration reduction holes (2) is 120 degrees in the direction of the structure to be protected.
6. The shallow hole blasting vibration reduction structure for the bridge pile group foundation based on the vibration reduction holes as claimed in claim 1, wherein the diameter of the vibration reduction holes (2) is the same as that of the peripheral holes (3).
7. A shock-absorbing hole-based shallow hole blast damping structure according to claim 1, wherein the depth of the shock-absorbing hole (2) is 0.2m greater than the peripheral hole (3).
8. A shallow hole blasting vibration reduction method for a bridge pile group foundation based on vibration reduction holes according to any one of claims 1-6, which is characterized by comprising the following steps:
A. punching a cutting hole (1) at a blasting position according to design requirements;
B. punching peripheral holes (3) on the outer side of the cut hole (1);
C. punching a damping hole (2) on the outer side of the peripheral hole (3) corresponding to the protection direction;
D. explosive is filled in the cut hole (1) and the peripheral hole (3), and the detonation is carried out after the safety is confirmed.
Technical Field
The invention relates to a blasting vibration reduction construction method, in particular to a shallow hole blasting vibration reduction structure and method for a bridge group pile foundation based on vibration reduction holes.
Background
The pile group foundation is the most common foundation form in the design of high piers and high towers of high-speed highway bridges in mountainous areas. The shallow hole blasting manual hole digging construction is used as an efficient and economic digging mode under the limitation of terrain, and is widely applied to pile foundation construction of highway bridge groups in mountainous areas. Engineering practices prove that in the process of blasting operation of a pile foundation, partial energy of explosives is transmitted around in the form of seismic waves to generate a seismic effect, when the seismic effect is strong and the wave velocity is high, the protective walls of adjacent pile holes and newly-poured pile body concrete are adversely affected, cracks appear in the protective walls and the pile body concrete, and finally potential safety hazards and potential quality hazards are formed. Therefore, in the shallow blasting excavation construction process of the bridge pile group foundation, blasting vibration reduction measures are needed to be adopted to control blasting vibration transmitted to adjacent piles.
At present, researches on blast damping measures mainly focus on two aspects: firstly, weakening the detonation source, such as reducing the maximum dosage, adjusting the differential time and the like; and secondly, changing the physical properties of the propagation medium, such as excavating vibration reduction grooves, vibration isolation holes and the like. However, in a highway project, piers and towers adopting a group pile foundation are often key work of the project, the requirement on the construction period is high, the work efficiency can be reduced and the construction progress can be delayed by adopting a method of reducing the drug amount to realize vibration reduction, the clear distance between the group pile foundation piles is small, the hole depth is large, and a vibration reduction groove can not be used obviously. For the vibration isolation hole, due to the characteristics of pile foundation construction, the position of the vibration isolation hole must be reasonably designed, and the purpose of vibration attenuation can be efficiently realized. The current blasting vibration reduction measures based on vibration reduction holes are mainly applied to tunnel blasting, relevant application is not found in pile group foundation shallow hole blasting construction, and tunnel blasting has no reference significance for bridge pile group foundation construction shallow hole blasting vibration reduction due to the problems of excavation sections, tunnel burial depths, blast hole arrangement schemes, protected structure intervals and the like.
Disclosure of Invention
The invention aims to provide a shallow hole blasting vibration reduction structure and a construction method of a bridge pile group foundation based on vibration reduction holes. The invention has the characteristics of reasonable structural design, small occupied area and good vibration damping effect.
The technical scheme of the invention is as follows: a bridge pile group foundation shallow hole blasting vibration reduction structure based on vibration reduction holes comprises cut holes, peripheral holes are arranged on the outer sides of the cut holes, and vibration reduction holes are arranged at the positions, with the distance of 0.08-0.12m, of the outer sides of the peripheral holes.
In the bridge pile group foundation shallow hole blasting vibration reduction structure based on the vibration reduction holes, the distance between the vibration reduction holes and the peripheral holes is 0.09-0.11 m.
In the bridge pile group foundation shallow hole blasting vibration attenuation structure based on the vibration attenuation holes, more than 2 vibration attenuation holes are arranged in an arc shape, and the circle center of the arc shape is the same as the blast holes and the peripheral holes.
In the bridge pile group foundation shallow hole blasting vibration reduction structure based on the vibration reduction holes, the distance between the vibration reduction holes is 0.2-0.3 m.
In the shallow hole blasting vibration reduction structure for the bridge pile group foundation based on the vibration reduction holes, the arc-shaped angle of the vibration reduction holes is 120 degrees in the direction of the structure to be protected.
According to the bridge pile group foundation shallow hole blasting vibration reduction structure based on the vibration reduction holes, the hole diameter of each vibration reduction hole is the same as that of the peripheral holes.
According to the bridge pile group foundation shallow hole blasting vibration reduction structure based on the vibration reduction holes, the depth of each vibration reduction hole is 0.2m greater than that of the peripheral hole.
The bridge pile group foundation shallow hole blasting vibration reduction method based on the vibration reduction holes comprises the following steps:
A. punching out a cutting hole at a blasting position according to design requirements;
B. punching peripheral holes on the outer sides of the cut holes;
C. punching vibration reduction holes on the outer sides of the peripheral holes corresponding to the protection direction;
D. filling explosive into the cut hole and the peripheral hole, and detonating after safety is confirmed.
The invention has the beneficial effects that: according to the regulations of blasting safety regulations (GB6722-2014), the safe allowable particle vibration speed of underground shallow hole blasting on a traffic tunnel (simulated dado) is 10-20 cm/s, and the allowable particle vibration speed of newly cast mass concrete (simulated pile body concrete) in the 7-day age is 10-12 cm/s. To prove the effectiveness of the method of the invention, the applicant carried out blasting vibration reduction experiments. The experiments were divided into the following two groups:
(1) reference experimental group: the operation is carried out according to the blasting design scheme without any vibration reduction and vibration isolation measures, as shown in figure 2, the left side is a
(2) Vibration isolation hole group: the method is adopted to add a row of vibration isolation holes outside the blasthole and the peripheral holes of the blasting operation hole, the distance between the vibration isolation holes is 0.25m and 0.1m from the peripheral holes, and the charge amount of each blasthole and the arrangement position of the sensor are consistent with the standard experiment set scheme.
The experiment adopts a TC-4850 Blasting vibration meter produced by Chengdu Zhongzhong Ke measurement and control Limited company to carry out Blasting vibration test, the tester is provided with an X, Y and Z three-dimensional integrated speed sensor and three-vector synthesis analysis software (shooting vibration analysis CBVA) software matched with the X, Y and Z three-dimensional integrated speed sensor. The experimental results are as follows:
(1) figure 3 shows the blast vibration waveform
(2) The maximum vibration speed and frequency are shown in Table 1
Table 1 blasting vibration test results
Tab.1 Result of Blasting Vibration Test
As can be seen from Table 1, the vibration frequency generated by the underground shallow-hole blasting is large, the half-wave dominant frequency is above 50Hz, the natural vibration frequency of the structure is usually low, and the influence of the vibration wave frequency on the adjacent pile foundations is small, so that the vibration wave speed is only used as an index for measuring the blasting influence. As can be seen from table 1 and fig. 3, before any vibration reduction measures are taken, the maximum value of the vibration wave speed transmitted to the adjacent pile hole retaining wall by the manual hole digging shallow hole blasting operation reaches 40.82cm/s, which is slightly larger than the theoretical value calculated by the sarofsky formula, and the vibration speed of the mass point is far higher than the allowable mass point for the safety of newly poured mass concrete in a traffic tunnel and 7 days of age specified by blasting safety regulations (GB6722-2014), and the necessity of taking the vibration reduction measures is also proved. By adding the vibration isolation hole measures, the maximum wave velocity is reduced to 8.78cm/s, the reduction amplitude reaches 78.5 percent, and the requirement of blasting in blasting safety regulations (GB6722-2014) on safe allowable particle vibration velocity of traffic tunnels and newly cast mass concrete in 7-day age is basically met.
Experiments prove that the design of the vibration isolation holes is the key for achieving the vibration reduction requirement, the vibration isolation hole setting parameters can be adaptively set according to the shallow hole blasting scheme of actual pile foundation excavation, the vibration isolation hole is suitable for the vibration reduction scenes of pile foundation blasting construction of different pile diameters and geology, and the same hole diameters as the peripheral holes and the undercut holes are adopted without adding extra drilling equipment and materials. Meanwhile, as the explosive charging structures of the cutting holes and the peripheral holes are not changed, the explosive source is not weakened, the blasting effect is good, and the shallow hole blasting vibration reduction structure and method for bridge grouped pile foundation construction based on the vibration isolation holes simultaneously realize high-efficiency vibration reduction and high-efficiency blasting. In actual engineering, the method combines the analysis, when the protected structure is only positioned in one direction, the cost is only increased by 425.6 yuan per blasting circulation by adopting a vibration isolation hole measure, the potential safety hazard and the quality problem of cracks of a retaining wall or a newly cast pile body of an adjacent pile foundation can be avoided, and the construction period and the construction indirect cost are greatly saved.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a reference experimental plan view;
fig. 3 is a diagram of a burst vibration waveform.
Detailed Description
The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.
Example 1 of the invention:
a bridge pile group foundation shallow hole blasting vibration reduction structure based on vibration reduction holes is shown in figure 1 and comprises cut holes 1, peripheral holes 3 are arranged on the outer sides of the cut holes 1, and vibration reduction holes 2 are arranged at the positions, with the distance of 0.08-0.12m, of the outer sides of the peripheral holes 3.
The distance between the vibration reduction holes 2 and the peripheral holes 3 is 0.09-0.11m, and the vibration reduction effect is ideal.
The damping holes 2 are more than 2 and are arranged in an arc shape, and the circle center of the arc shape is the same as that of the blastholes 1 and the peripheral holes 3. In a better setting scheme, the distance between the vibration reduction holes 2 is 0.2-0.3 m. The arc angle of the vibration reduction hole 2 is 120 degrees in the direction of a structure to be protected.
In order to realize the vibration damping effect, the diameter of the vibration damping hole 2 is the same as that of the peripheral hole 3, and the depth of the vibration damping hole 2 is 0.2m greater than that of the peripheral hole 3.
The bridge pile group foundation shallow hole blasting vibration reduction method based on the vibration reduction holes comprises the following steps:
A. punching a cutting hole 1 at a blasting position according to design requirements;
B. punching peripheral holes 3 on the outer sides of the cutting holes 1;
C. punching a damping hole 2 outside the peripheral hole 3 corresponding to the protection direction;
D. explosive is filled in the cut hole 1 and the peripheral hole 3, and the detonation is carried out after the safety is confirmed.
Example 2 of the invention:
a bridge pile group foundation shallow hole blasting vibration reduction structure based on vibration reduction holes is shown in figure 1 and comprises cut holes 1, peripheral holes 3 are arranged on the outer sides of the cut holes 1, and vibration reduction holes 2 are arranged at the positions, with the distance of 0.1m, of the outer sides of the peripheral holes 3.
The damping holes 2 are more than 2 and are arranged in an arc shape, and the circle center of the arc shape is the same as that of the blastholes 1 and the peripheral holes 3. In a more preferable arrangement, the distance between the vibration damping holes 2 is 0.25 m. The arc angle of the vibration reduction hole 2 is 120 degrees in the direction of a structure to be protected.
In order to realize the vibration damping effect, the diameter of the vibration damping hole 2 is the same as that of the peripheral hole 3, and the depth of the vibration damping hole 2 is 0.2m greater than that of the peripheral hole 3.
The method for damping shallow hole blasting of the bridge pile group foundation based on the damping holes is as in embodiment 1.
The above description is only for the purpose of illustrating the present invention and the appended claims, and the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
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