WO2022116749A1

WO2022116749A1 - Method for reducing vibration speed in tunnel blasting excavation in sensitive urban environment

Info

Publication number: WO2022116749A1
Application number: PCT/CN2021/126725
Authority: WO
Inventors: 高海东; 潘建立; 王学斌; 赵映冠; 李刚; 郭彦兵; 孙磊; 宋发雄; 薛翊国; 郑涛; 王军堂
Original assignee: 中铁十八局集团第一工程有限公司; 中铁十八局集团有限公司
Priority date: 2020-12-01
Filing date: 2021-10-27
Publication date: 2022-06-09
Also published as: CN112504041A; KR20220140899A; CN112504041B

Abstract

A method for reducing vibration speed in tunnel blasting excavation in a sensitive urban environment, comprising the following steps: step 1, performing a blasting control test at a section relatively far away from a sensitive building; step two, using a top CD construction method as an excavation construction method, and determining lining support parameters; step 3, performing top CD pilot tunnel lining design for the III-IV-level surrounding rock, and determining pilot tunnel support parameters; step 4, excavating an upper-bench left pilot tunnel (1) and right pilot tunnel (2) step by step; step five, providing a middle pipe roof before excavation; step 6, uniformly forming a plurality of peripheral holes (4) in the inner walls of the left pilot tunnel and right pilot tunnel; step 7, detonating one electronic detonator for each hole; step 8, controlling the blasting depth; and step 9, filling the peripheral eyes with the explosives. The method reduces the blasting vibration speed, reduces damage to buildings and structures and impact on surrounding residents, and achieves "blasting with imperceptible vibration" and "environment-friendly construction".

Description

A method for reducing the vibration speed of tunnel blasting in sensitive urban environment

technical field

The invention relates to the field of controlled blasting construction of tunnels adjacent to sensitive buildings, in particular to a method for reducing the vibration speed of tunnel blasting and excavation in a sensitive urban environment.

Background technique

The 21st century is the century of large-scale development of underground space. With the continuous expansion of the construction scale of urban underground space in my country, the construction environment has become more and more complex. more common. How to realize fine blasting control of hard rock section, reduce blasting vibration speed to the greatest extent, reduce the impact on surrounding buildings (structures), reduce the impact on the daily life of surrounding residents, and strive to "non-inductive blasting" to improve tunnels The quality of blasting excavation can increase the self-stabilizing ability of surrounding rock and reduce various risks in the process of tunnel construction. There are few domestic and foreign engineering cases that can be referenced, which is worthy of our further in-depth study.

The traditional controlled blasting is mostly to increase the number of perforations, more perforation, less charge, separate charge, and segmented detonation; the more advanced ones currently use digital electronic detonators instead of detonators to reduce blasting vibration. Although the existing technology can reduce the blasting vibration speed to about 0.8 ~ 1.0cm/s, it meets the "safety allowable vibration speed value of general civil buildings: when the main frequency is 10 ~ 50Hz, the safe allowable vibration speed is 2.0 ~ 2.5cm/s" ”, but it still has a certain impact on the nearby sensitive buildings and the daily life of the surrounding residents, bringing more complaints from residents, which is not conducive to the progress of the project construction, and does not implement the concept of green engineering and environmental protection.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for reducing the vibration speed of tunnel blasting and excavation under a sensitive urban environment, so as to solve the problems of high blasting vibration speed, causing damage to buildings (structures), affecting surrounding residents, and causing damage to surrounding rock. .

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

The present invention is a method for reducing the vibration speed of tunnel blasting and excavation in an urban sensitive environment, comprising the following steps:

Step 1: Carry out explosion control tests in sections relatively far away from sensitive buildings, simulate the construction conditions of adjacent sensitive buildings, collect data from the test section, and determine a specific construction plan after evaluating the safety of sensitive buildings;

Step 2: Use the upper CD method as the excavation method to determine the lining support parameters;

Step 3: According to the lining support parameters determined in the second step, carry out the lining design of the CD pilot pit on the surrounding rock of grade III-IV, and determine the support parameters of the pilot pit;

Step 4: Step-by-step implementation of the left pilot hole and the right pilot hole on the upper step. The left pilot hole and the right pilot hole are respectively provided with a city gate type advanced pilot hole, and a hollow space is arranged in the middle of the city gate type advanced pilot hole. Vibration damping hole;

Step 5: Set up a middle pipe shed before excavation, and the empty pipe is not grouted;

Step 6: evenly arrange several peripheral eyes on the inner wall of the left pilot hole and the right pilot hole;

Step 7: install electronic detonators in the peripheral eyes, and install electronic detonators in each of the peripheral eyes;

Step 8: Control the blasting footage, the city gate type advanced pilot hole is advanced twice in a row, and then the top is pressed at one time, and the total footage is ≯ 4 steel frames;

Step 9: Loading explosives in the peripheral eye.

Further, in the third step, the lining of the guide pit includes initial lining, a plurality of hollow grouting bolts are evenly arranged on the outer side of the initial lining, and supports and secondary linings are arranged on the inner side of the initial lining. The interior of the secondary lining is provided with a road surface, and the hollow grouting bolts are arranged in a plum blossom shape.

Still further, described road surface is arranged successively from top to bottom as asphalt surface layer, cement concrete road panel, road base, concrete inverted arch backfill layer, reinforced concrete inverted arch, described reinforced concrete inverted arch adopts I-beam to build and is in. Surface shotcrete.

Still further, a temporary support is arranged above the road surface, the temporary support is arranged in an inverted T-shaped structure, the center of the temporary support is located on the center line of the lining, and the upper part and the left and right ends of the temporary support are the same as the initial one. The support arch is connected, and the upper part of the temporary support is provided with a medicine roll anchor, and the medicine roll anchor is arranged in a plum blossom shape.

Still further, in the fourth step, the hole depth of the hollow vibration damping hole is the same as the length of the tube shed.

Still further, in the step 6, the distance between the peripheral eyes is ≯ 40cm.

Still further, in the ninth step, the single-hole charge is controlled to be ≯ 1.2kg.

Compared with the prior art, the beneficial technical effects of the present invention:

The invention adopts the upper CD excavation method for the hard rock section adjacent to the sensitive buildings, the step-by-step implementation of the left and right pilot holes on the upper steps, the left and right pilot holes are provided with advanced pilot holes, the advanced middle pipe shed is vibration-damped, the vibration-damping holes are set, and the peripheral holes are densified. , The construction method of electronic detonator single hole and single sound, control of blasting footage, control of single-hole charge, greatly reduces the blasting vibration speed, greatly reduces the damage to buildings (structures) and the impact on surrounding residents, Realize "non-inductive blasting" and "green environmental protection construction"; greatly reduce blasting vibration, reduce damage to surrounding rock, further improve the quality of smooth blasting and the self-supporting capacity of surrounding rock after blasting, reduce tunnel vaulting The possibility of local surrounding rock dropping blocks improves the safety of the tunnel excavation operating environment; shortens the delay time of electronic detonators, and sets double detonators in the bottom hole to reduce blind shots, reduce the explosion rate of electronic detonators, and improve safe use; fine automation Blasting vibration monitoring provides guidance for blasting control.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings.

Fig. 1 is the positional relationship diagram of tunnel construction and adjacent buildings of the present invention;

Fig. 2 is the lining support design drawing of the present invention;

3 is a schematic diagram of the pavement structure of the present invention;

Fig. 4 is the design drawing of guide pit support according to the present invention;

Fig. 5 is the drilling and blasting design drawing of the present invention;

Fig. 6 is the blasting vibration monitoring point layout diagram of the left pilot hole of the present invention;

Fig. 7 is the blasting vibration monitoring point layout diagram of the right pilot hole of the present invention;

Explanation of reference numerals: 1. Left pilot hole; 2. Right pilot hole; 3. Advance pilot hole in the city gate; 301. Hollow vibration damping hole; 4. Peripheral eye; 5. Secondary lining; 6. Support; 7. Preliminary masonry; 8. Hollow grouting bolt; 9. Road surface; 10. Temporary support; 11. Coil bolt; 12. Fifth monitoring point; 13. First monitoring point; 14. Second monitoring point; 15. The third monitoring point; 16. The fourth monitoring point.

Detailed ways

As shown in Figure 1-7, a method for reducing the vibration speed of tunnel blasting in a sensitive urban environment includes the following steps:

Step 2: Use the upper CD method as the excavation method to determine the parameters of the lining support; the specific parameters are set as: D25 hollow grouting bolt @60×120cm, 28cmC25 shotcrete, φ8 steel mesh@20×20cm, 20b work Steel beam@60cm, φ8 steel mesh@20×20cm, 50cmC50 reinforced concrete secondary lining; inverted arch 28cmC25 shotcrete, 20b I-beam@60cm, 55cmC50 reinforced concrete inverted arch;

Step 4: The left pilot hole 1 and the right pilot hole 2 are implemented step by step. The left pilot hole 1 and the right pilot hole 2 are respectively set with a 4.5×3.5m (width×height) city gate type advanced pilot hole 3 , two rows of φ100 hollow vibration damping holes 301 are arranged in the middle of the city gate type advanced pilot hole 3, the layer spacing is 0.3m, the row spacing is 0.5m, and the hole depth is the same as the length of the tube shed;

Step 5: Set up a middle pipe shed before excavation, without grouting for empty pipes, taking into account the effects of advanced support and vibration reduction;

Step 6: Evenly arrange several peripheral eyes 4 on the inner walls of the left guide hole 1 and the right guide hole 2, and the distance between the peripheral eyes 4 is ≯ 40cm;

Step 7: install the electronic detonator in the peripheral eye 4, and install the electronic detonator in each of the peripheral eye 4;

Step 8: Control the blasting footage, the city gate type advanced pilot hole 3 is advanced twice in a row, and then the top is pressed at one time, and the total footage is ≯ 4 steel frames;

Step 9: Fill the peripheral eye 4 with explosives, control the single-hole charge ≯ 1.2kg; shorten the delay time of the electronic detonator, set up double detonators in the bottom hole, reduce blind shots, reduce the explosion rate of the electronic detonator, and improve the safety of use. .

Specifically, in the first step, the distance between adjacent buildings and the tunnel D1 is 6m, D2 is 22m, D3 is 12m, D4 is 20.1m, D5 is 23.8m, and the minimum distance is only 6m.

In the third step, the lining of the pilot pit includes a preliminary lining 7, a plurality of hollow grouting bolts 8 are evenly arranged on the outer side of the initial lining 7, and a support 6 and a secondary lining are arranged on the inner side of the initial lining 7. 5. The interior of the secondary lining 5 is provided with a road surface 9, the hollow grouting bolt 8 is a D25 anti-corrosion hollow grouting bolt, the length is 350cm, and the longitudinal and circumferential spacing is 60 (longitudinal) * 120 (ring), Adopt plum-blossom-shaped arrangement; described initial build 7 adopts steel bar with a diameter of 8cm and a spacing of 20*20cm to build a steel mesh, and sprays 28cm-thick C25 shotcrete on the steel mesh; described support 6 uses 20b I-beam, Set the spacing of 60cm to form a main support frame, then use steel bars with a diameter of 8cm and a spacing of 20*20cm to build a steel mesh, and coat the steel mesh with a composite waterproof layer; the secondary lining 5 is used in the The inner side of support 6 is sprayed with 50cm thick C50 reinforced concrete.

Described road surface 9 is arranged successively from top to bottom as asphalt surface layer 91, cement concrete road panel 92, road base 93, concrete inverted arch backfill 94, reinforced concrete inverted arch 95, and described reinforced concrete inverted arch 95 adopts 20b I-shaped Steel construction, the spacing is set to 60cm, and 28cm thick C25 shotcrete is set on the surface; the asphalt surface layer 91 is set to 10cm, the cement concrete pavement panel 92 is set to 26cm, the road base 93 is set to 20cm, the Concrete inverted arch backfill layer 94 adopts C15 concrete inverted arch backfill, and described reinforced concrete inverted arch 95 adopts C50 reinforced concrete inverted arch, and size is set to 55cm.

A temporary support 10 is arranged above the road surface 9. The temporary support 10 is arranged in an inverted T-shaped structure. The center of the temporary support 10 is located on the center line of the lining. The initial support arch frame is connected, and the temporary support adopts I20b I-beam@60cm, builds a φ6.5 steel mesh (20*20cm) around the I-beam, and sprays C25 shotcrete with a thickness of 22cm; the temporary support 10 The upper part is provided with a medicine roll anchor 11, the length of the medicine roll anchor 11 is 200cm, the longitudinal and circumferential distances are 60*120cm, and the arrangement is in a plum blossom shape.

The present invention completes the controlled blasting construction of tunnels adjacent to sensitive buildings through the above steps. One shot and one measurement. In the controlled blasting test section, the construction conditions of adjacent sensitive buildings are simulated, and automatic blasting monitoring points are arranged along the 6m line on the side of the building, each 10m away. , collect the data of the test section; the outer side of the left pilot hole 1 is provided with a fifth monitoring point 12, and the outer side of the right pilot hole 2 is arranged with a first monitoring point 13, a second monitoring point 14, and a third monitoring point at equal intervals 15 and the fourth monitoring point 16, according to the data sample analysis, the blasting vibration speed of 90% of the blasting monitoring points is 0.3cm/s, which is much lower than the standard value of 2.0cm/s, and has little impact on the surrounding buildings.

The invention minimizes the blasting vibration speed, reduces the damage to buildings (structures) and the impact on surrounding residents, and realizes "non-inductive blasting" and "green environmental protection construction"; reduces blasting vibration and reduces the impact on surrounding rocks. damage, improve the quality of smooth blasting and the self-supporting capacity of the surrounding rock after blasting, so that the surrounding rock around the tunnel is not damaged or less damaged, and it is not easy to drop blocks or collapse.

The above-mentioned embodiments are only to describe the preferred mode of the present invention, but not to limit the scope of the present invention. Without departing from the design spirit of the present invention, those of ordinary skill in the art can Variations and improvements should fall within the protection scope determined by the claims of the present invention.

Claims

A method for reducing the vibration speed of tunnel blasting and excavation in a sensitive urban environment, comprising the following steps:

Step 1: Carry out explosion control tests in sections relatively far away from sensitive buildings, simulate the construction conditions of adjacent sensitive buildings, collect data from the test section, and determine a specific construction plan after evaluating the safety of sensitive buildings;

Step 2: Use the upper CD method as the excavation method to determine the lining support parameters;

Step 3: According to the lining support parameters determined in the second step, carry out the lining design of the CD pilot pit on the surrounding rock of grade III-IV, and determine the support parameters of the pilot pit;

Step 4: Step-by-step implementation of the left pilot hole (1) and the right pilot hole (2) on the upper steps, and the gate hole type advanced pilot hole (3) is respectively set in the left pilot hole (1) and the right pilot hole (2). ), and a hollow vibration damping hole (301) is arranged in the middle of the city gate hole-type advanced pilot hole (3);

Step 5: Set up a middle pipe shed before excavation, and the empty pipe is not grouted;

Step 6: evenly arranging several peripheral eyes (4) on the inner walls of the left guide hole (1) and the right guide hole (2);

Step 7: installing electronic detonators in the peripheral eyes (4), and installing electronic detonators in each of the peripheral eyes (4);

Step 8: Control the blasting footage, the city gate type advanced pilot hole (3) is advanced twice in a row, and then the top is pressed at one time, and the total footage is ≯ 4 steel frames;

Step 9: Fill the peripheral eye (4) with explosives.
The method for reducing the vibration speed of tunnel blasting and excavation in urban sensitive environment according to claim 1, characterized in that: in the step 3, the lining of the pilot pit comprises a preliminary masonry (7), and the preliminary masonry (7) A plurality of hollow grouting bolts (8) are evenly arranged on the outer side of the primary lining (7), a support (6) and a secondary lining (5) are arranged on the inner side of the primary lining (7), and the inner lining (5) is provided with a support (6) and a secondary lining (5). There is a road surface (9), and the hollow grouting bolts (8) are arranged in a plum blossom shape.
The method for reducing the vibration speed of tunnel blasting and excavation in an urban sensitive environment according to claim 2, characterized in that: the road surface (9) is sequentially arranged from top to bottom as an asphalt surface layer (91), a cement concrete road surface ( 92), pavement base (93), concrete inverted arch backfill layer (94), reinforced concrete inverted arch (95), described reinforced concrete inverted arch (95) adopts I-beam to build and spray concrete on the surface.
The method for reducing the vibration speed of tunnel blasting excavation in an urban sensitive environment according to claim 2, characterized in that: a temporary support (10) is arranged above the road surface (9), and the temporary support (10) is arranged as Inverted T-shaped structure, the center of the temporary support (10) is located on the center line of the lining, the upper part and the left and right ends of the temporary support (10) are connected with the primary support arch, the upper part of the temporary support (10) A medicine roll anchor (11) is provided, and the medicine roll anchor (11) is arranged in a plum blossom shape.
The method for reducing the vibration speed of tunnel blasting and excavation in urban sensitive environment according to claim 1, characterized in that: in the step 4, the hole depth of the hollow vibration damping hole (301) is the same as the length of the pipe shed.
The method for reducing the vibration speed of tunnel blasting and excavation in an urban sensitive environment according to claim 1, characterized in that: in the step 6, the distance between the peripheral eyes (4) is ≯ 40cm.
The method for reducing the vibration speed of tunnel blasting and excavation in an urban sensitive environment according to claim 1, characterized in that: in the ninth step, the single-hole charge is controlled to be ≯ 1.2kg.