CN113739656B

CN113739656B - Stone blasting excavation method under deep foundation pit supporting beam

Info

Publication number: CN113739656B
Application number: CN202111102815.7A
Authority: CN
Inventors: 钱起飞; 高杨; 王建鹏; 黄国荣; 胡俊
Original assignee: First Construction Co Ltd of China Construction Eighth Engineering Division Co Ltd
Current assignee: First Construction Co Ltd of China Construction Eighth Engineering Division Co Ltd
Priority date: 2021-09-22
Filing date: 2021-09-22
Publication date: 2023-01-24
Anticipated expiration: 2041-09-22
Also published as: CN113739656A

Abstract

The invention relates to the technical field of building construction, in particular to a blasting excavation method for a stone below a deep foundation pit supporting beam, which comprises the following steps: cleaning a working surface, hole distribution/drilling, hole inspection, charging, filling, connecting a blasting network, blasting safety protection and blasting warning/initiation. The beneficial effects are that: the blasting method provided by the invention can effectively protect the supporting beam through the reserved broken stone protective layer, has good blasting effect, small size of broken stones generated by blasting, easy shoveling and cleaning, lower construction cost compared with mechanical excavation, more economical initiating explosive devices compared with expanding agents used in static blasting, safer compared with the traditional blasting method, and can effectively prevent fragments generated by blasting from splashing and effectively reduce blasting dust, thereby meeting the requirement of environmental protection.

Description

Stone blasting excavation method under deep foundation pit supporting beam

Technical Field

The invention relates to the technical field of building construction, in particular to a method for blasting and excavating below a deep foundation pit supporting beam by stone.

Background

With the development of city construction process in China, the bottom buildings of major business circles are gradually replaced by super high-rise buildings, and the super high-rise buildings also start to play an indispensable role in the city construction process. In the process of super high-rise building construction, along with the increase of underground space development and utilization, the depth of the foundation pit of the building is deeper and deeper. In the excavation construction process of the ultra-deep foundation pit, a supporting system of an inner support and a supporting pile is generally adopted, the operation space provided by the ultra-deep foundation pit under the supporting system is narrow, large construction machinery is difficult to enter, and the mechanical excavation is difficult to deploy; the construction efficiency of manual direct excavation is low, the labor intensity of workers is high, and the air supply is long; expensive expanding agents are needed for manual static blasting excavation, and construction cost is high; and the influence on a supporting system during blasting is difficult to effectively control in the traditional blasting excavation mode, the flyrock generated by blasting is difficult to effectively protect, and the safety and the reliability are low. Therefore, an effective excavation method for the stone below the supporting beam in the ultra-deep foundation pit is needed.

Disclosure of Invention

The invention aims to provide a blasting excavation method for a stone below a support beam of a deep foundation pit, which aims to solve the problem that the stone below an inner support beam of the ultra-deep foundation pit is difficult to excavate in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a method for blasting and excavating below stone of a deep foundation pit supporting beam comprises the following steps:

s1, cleaning a working surface: before blasting construction and after each round of blasting circulation, timely cleaning away dregs on a rock working surface to be blasted, wherein the left thickness of the dregs is not more than 50mm, and reserving a broken stone protective layer which is not less than 300mm below a supporting beam fixed by an upright column above a blasting position for protecting the supporting beam during cleaning;

s2, hole distribution/drilling: when arranging blast holes on the front side surface of the rock to be blasted, a quincunx hole arrangement mode is adopted, constructors use a total station to carry out paying-off and hole arrangement, the hole depth of the blast holes is 3.0m, the hole pitch is 1.5m, the row pitch is 0.8m, the blast holes adopt a drilling mode of inclining downwards, and the inclination angle between the blast holes and the rock structure surface is controlled within the range from 60 degrees to 70 degrees;

s3, hole inspection: the gun stick is adopted to check the depth and the drilling angle of the blast hole, the blast hole beyond the designed depth is filled with drilling powder slag, the powder slag is slowly released during filling to avoid being blocked into a waste hole, the blast hole with the depth not reaching the standard is drilled and deepened again, the accumulated water in the blast hole is blown clean by a high-pressure pipe, and the blast hole which still does not reach the standard after being repaired is processed by adopting a mode of selecting a nearby position to drill again after being abandoned;

s4, charging: the explosive is loaded at intervals, the amount of explosive in a single hole is 3kg, the detonator is completely inserted into one third of the upper part of the explosive cartridge, the detonator wire is wound around the explosive cartridge for one circle to prevent the detonator from being pulled out in the explosive loading process, and then the explosive cartridge is lightly pressed into the bottom of the blast hole by a gun barrel;

s5, filling: filling the blast hole after the charging to form a filling section, wherein the filling material uses sandy clay, when water exists in the blast hole, fine sand grains and a woven mesh are used for filling, the filling length is not less than 25 times of the diameter of the blast hole, simultaneously, a gun stick is used for tamping every 20cm of filling, and the step S4 are alternately carried out until the construction of the corresponding blast hole is finished;

s6, connecting a blasting network: after all blast holes are filled and plugged, connecting the detonator wire into a blasting network, and then connecting the blasting network to a detonating line;

s7, blasting safety protection: adopting a steel plate with the thickness of 2cm to carry out integral protection on the rock structure surface at the blasting position, wherein the overlapping area between the steel plates is not less than 20cm, the steel plate covering area extends outwards to be not less than 1.0m away from the blasting area, the inclination angle between the steel plate and the ground is not more than 75 degrees, and then covering a slag soil layer with the thickness of not less than 500mm and not less than the height of the highest blast hole on the back surface of the steel plate to carry out protection;

s8, blasting warning/detonation: and (3) starting warning before the detonation lasts for 30min, evacuating personnel and vehicles in the blasting area to the safe area, then enabling the detonator to reach a detonation point, checking a detonation network and a detonation device, then connecting a detonation wire into a detonator to complete the detonation operation after receiving a detonation command within a preset detonation time, and entering the next round of blasting circulation after the detonation is completed.

Preferably, the number of the S4 traditional Chinese medicine rolls 9 is two, and the medicine loading of the medicine rolls 9 arranged at the bottom of the blast hole 5 accounts for 17-35% of the total medicine loading of a single hole.

Preferably, the adjacent cartridges 9 in S5 are isolated by air spacer, and the specific method is to cut the PVC pipe into the corresponding length of the spacer after filling the first section of explosive 9, then insert the PVC pipe into the blast hole 5, then fill the second section of cartridges 9, sequentially complete the setting of each section of cartridge 9 and the setting of the air spacer, and finally plug the orifice of the blast hole 5 by using the method in S4.

Preferably, the depth of the blast hole 5 in the S2 is changed to 2.0m, and the loading amount of the single hole in the S4 is changed to 2kg, so that the excavation time in the blasting circulation is shortened.

Compared with the prior art, the invention has the beneficial effects that: the blasting method provided by the invention can effectively protect the supporting beam through the reserved broken stone protective layer, has good blasting effect, small size of broken stones generated by blasting, easy shoveling and cleaning, lower construction cost compared with mechanical excavation, more economical initiating explosive devices compared with expanding agents used in static blasting, safer compared with the traditional blasting method, and can effectively prevent fragments generated by blasting from splashing and effectively reduce blasting dust, thereby meeting the requirement of environmental protection.

Drawings

FIG. 1 is a schematic view of a blast hole arrangement according to the present invention;

fig. 2 is a schematic diagram of the explosion protection of the present invention.

In the figure: 1. rock to be blasted; 2. a column; 3. a support beam; 4. a macadam protection layer; 5. blast holes; 6. a rock structural surface; 7. a steel plate; 8. a slag soil layer; 9. medicated rolls; 10. and (6) plugging the section.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art without creative efforts based on the technical solutions of the present invention belong to the protection scope of the present invention.

Referring to fig. 1 to 2, the present invention provides a technical solution: a method for blasting and excavating below stone of a deep foundation pit supporting beam comprises the following steps:

s1, cleaning a working surface: before blasting construction and after each round of blasting circulation, timely cleaning away dregs on the working surface of the rock 1 to be blasted, wherein the remaining thickness of the dregs is not more than 50mm, reserving a broken stone protective layer 4 which is not less than 300mm below a supporting beam 3 fixed by an upright post 2 above a blasting position for protecting the supporting beam 3 during cleaning, the width of the supporting beam is 1m, and the net thickness of the rock 1 to be blasted below the supporting beam 3 is 3.8m;

s2, hole distribution/drilling: when arranging blast holes 5 on the front side surface of the rock 1 to be blasted, a quincunx hole arrangement mode is adopted, constructors use a total station to carry out paying-off and hole arrangement, the hole depth of each blast hole 5 is 3.0m, the hole distance is 1.5m, the row distance is 0.8m, the hole diameter is 76mm, each blast hole 5 adopts a drilling mode of inclining downwards, and the inclination angle between each blast hole 5 and the rock structure surface 6 is controlled within the range of 60-70 degrees;

s3, hole inspection: the depth and the drilling angle of the blast hole 5 are checked by adopting a gun rod, the blast hole beyond the designed depth is filled with drilling powder slag, the powder slag is slowly released during filling to avoid being clamped into a waste hole, the blast hole 5 with the depth not reaching the standard is drilled and deepened again, a high-wind pressure pipe is adopted to blow off accumulated water in the blast hole 5, and the blast hole 5 which still does not reach the standard after repair is treated by selecting a nearby position after abandonment and drilling again;

s4, charging: the explosive is of an interval loading structure, the amount of explosive in a single hole is 3kg, a detonator is completely inserted into one third of the upper part of a cartridge 9, a detonator wire is wound around the cartridge 9 for one circle to prevent the detonator from being pulled out in the loading process, then a gun rod is adopted to lightly press the cartridge 9 into the bottom of a blast hole 5, the explosive is a No. 2 rock emulsion explosive, the diameter is 32mm, the length of the single cartridge is 20cm, the weight is 0.2kg, and the explosive is bundled into a cartridge to form the cartridge 9;

s5, filling: filling the blast holes 5 after the charging is finished to form filling sections 10, wherein the filling material is sand clay, when water exists in the blast holes 5, fine sand grains and a woven net are used for filling, the filling length is not less than 25 times of the diameter of the blast holes 5, and simultaneously, a gun rod is used for tamping every 20cm of filling, and the step S4 are alternately carried out until the construction of the corresponding blast holes 5 is finished;

s6, connecting a blasting network: after all the blast holes 5 are filled and filled, the detonator wires are connected to form an explosion network and then connected to a detonating line;

s7, blasting safety protection: the rock structure surface 6 of the blasting position is integrally protected by adopting a steel plate 7 with the thickness of 2cm, the specification of the steel plate is 6 multiplied by 3m, the overlapping area between the steel plates 7 is not less than 20cm, the outer side surface of the steel plate 7 can be welded with a support rib, a support plate or a support frame which is in contact with the ground to prevent the steel plate 7 from sliding, the covering area of the steel plate 7 extends outwards to be not less than 1.0m away from the blasting area, the inclination angle between the steel plate 7 and the ground is not more than 75 degrees, and then the back of the steel plate 7 is covered with a slag soil layer 8 which is not less than 500mm thick and is not less than the height of the highest blast hole 5 for protection;

s8, blasting warning/detonation: and (3) starting warning before 30min of blasting, evacuating personnel and vehicles in the blasting area to the safe area, then enabling the blaster to reach a blasting point, checking a blasting network and a blasting apparatus, then connecting a blasting wire into a blasting machine to complete blasting operation after receiving a blasting command in preset blasting time, and entering the next blasting cycle after blasting is completed.

The blasting method provided by the invention can also be optimized in the following way: s4, two traditional Chinese medicine rolls 9 are adopted, and the medicine loading amount of the medicine roll 9 arranged at the bottom of the blast hole 5 accounts for 17-35% of the total medicine loading amount of a single hole; s5, isolating adjacent cartridges 9 by adopting air separation sections, wherein the specific method comprises the steps of cutting a PVC pipe with the diameter of 64mm into the length of 0.5m after filling the first section of explosive 9, then inserting the PVC pipe into the blast hole 5, then filling the second section of cartridges 9, sequentially finishing the setting of each section of cartridge 9 and the setting of the air separation sections, and finally filling the orifice of the blast hole 5 by using the mode in S4; the depth of the blast hole 5 in the S2 is changed to 2.0m, and meanwhile the loading of the single hole in the S4 is changed to 2kg, so that the excavation time in the blasting circulation is shortened.

Blasting effect: the unique blast hole design and arrangement mode and the air space charging structure ensure that the explosion energy of the explosive is uniformly distributed in the rock mass, the rock mass after explosion is moderate, most of the rock mass is concentrated between 10cm and 30cm, and particularly in the blast hole filling section, the rock mass rate is obviously reduced, and only individual rock fragments with the mass of more than 50cm exist; the supporting beam 3 has no obvious damage, and is particularly characterized by having no obvious cracks; blasting vibration of key buildings (structures) around the blasting area is less than 3m/s, and the related regulations are met.

The blasting method provided by the invention can effectively protect the supporting beam 3 through the reserved broken stone protective layer 4, the arrangement mode of the blast holes 5 adopted by the blasting method is good in blasting effect, the broken stones generated by blasting are small in size and easy to shovel, the construction cost is lower compared with mechanical excavation, the used blasting articles are more economical compared with an expanding agent used in static blasting, and the blasting method is safer compared with the traditional blasting method, meanwhile, the arrangement mode of the blast holes 5 used by the blasting method and the protection of the steel plate 7 and the slag soil layer 8 are adopted, the fragments generated by blasting can be effectively prevented from splashing, blasting dust can be effectively reduced, and the blasting method meets the requirement of environmental protection, so that the blasting method has high practical value.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A method for blasting and excavating below stone of a deep foundation pit supporting beam is characterized by comprising the following steps:

s1, cleaning a working surface: before blasting construction and after each round of blasting circulation, timely cleaning away dregs on the working surface of the rock (1) to be blasted, wherein the remaining thickness of the dregs is not more than 50mm, and reserving a broken stone protective layer (4) which is not less than 300mm below a supporting beam (3) fixed above a blasting position by adopting an upright post (2) for protecting the supporting beam (3) during cleaning;

s2, hole distribution and drilling: when arranging blast holes (5) on the front side surface of the rock (1) to be blasted, a quincunx hole arrangement mode is adopted, constructors use a total station to carry out paying-off and hole arrangement, the hole depth of each blast hole (5) is 3.0m, the hole distance is 1.5m, the row distance is 0.8m, each blast hole (5) adopts an inclined downward drilling mode, and the inclination angle between each blast hole (5) and the rock structure surface (6) is controlled within the range of 60-70 degrees;

s3, hole inspection: the depth and the drilling angle of the blast hole (5) are checked by adopting a gun stick, the blast hole beyond the designed depth is filled by adopting drilling powder slag, the powder slag is slowly released during filling to avoid being blocked into a waste hole, the blast hole (5) with the depth not reaching the standard is drilled and deepened again, a high-wind pressure pipe is adopted to blow off accumulated water in the blast hole (5), and the blast hole (5) which still does not reach the standard after being repaired is treated by adopting a mode of selecting a nearby position to drill again after being abandoned;

s4, charging: the explosive loading structure is arranged at intervals, the explosive loading amount in a single hole is 3kg, the detonator is completely inserted into one third of the upper part of the explosive cartridge (9), the detonator wire is wound around the explosive cartridge (9) for one circle to prevent the detonator from being pulled out in the explosive loading process, and then the explosive cartridge (9) is lightly pressed into the bottom of the blast hole (5) by a gun rod;

s5, filling: filling the blast holes (5) after the charging is finished to form filling sections (10), wherein the filling material is sand clay, when water exists in the blast holes (5), fine sand grains and a woven net are used for filling, the filling length is not less than 25 times of the diameter of the blast holes (5), a gun stick is used for tamping every 20cm of filling, and the step S4 are alternately carried out until the construction of the corresponding blast holes (5) is finished;

s6, connecting a blasting network: after all blast holes (5) are filled and filled, the detonator wire is connected to form a blasting network and then connected to a detonating line;

s7, blasting safety protection: the rock structure surface (6) at the blasting position is integrally protected by adopting a steel plate (7) with the thickness of 2cm, the overlapping area between the steel plates (7) is not less than 20cm, the covering area of the steel plate (7) extends outwards to be not less than 1.0m away from the blasting area, the inclination angle between the steel plate (7) and the ground is not more than 75 degrees, and then a slag soil layer (8) with the thickness of not less than 500mm and the height not less than the highest blast hole (5) is covered on the back surface of the steel plate (7) for protection;

s8, blasting warning and detonation: and (3) starting warning 30 minutes before detonation, evacuating personnel and vehicles in the blasting area to the safe area, then enabling the detonating personnel to reach a detonation point, checking a detonation network and a detonating apparatus, then connecting a detonating cord into a detonator after a detonating command is received in preset detonating time to complete the detonation operation, and entering the next round of blasting circulation after the detonation is completed.

2. The method for blasting excavation under the deep foundation pit supporting beam stone as claimed in claim 1, wherein the method comprises the following steps: the number of the S4 traditional Chinese medicine rolls (9) is two, and the medicine loading amount of the medicine rolls (9) arranged at the bottom of the blast hole (5) accounts for 17-35% of the total medicine loading amount of a single hole.

3. The method for blasting excavation under the deep foundation pit supporting beam stone as claimed in claim 1, wherein the method comprises the following steps: the method comprises the specific steps that after a first section of the explosive roll (9) is filled, a PVC pipe is cut into the length of the corresponding interval, the interval is inserted into a blast hole (5), a second section of the explosive roll (9) is filled, the arrangement of each section of the explosive roll (9) and the arrangement of the air interval are sequentially completed, finally, a filling material is used for filling the orifice of the blast hole (5), the filling material is sand clay, when water exists in the blast hole (5), fine sand grains and a woven mesh are used for filling, and a gun stick is used for tamping every 20cm of filling.

4. The method for blasting excavation of the stone below the deep foundation pit supporting beam, according to claim 1, is characterized in that: the depth of the blast hole (5) in the S2 is changed to 2.0m, and meanwhile, the single-hole loading in the S4 is changed to 2kg, so that the excavation time in the blasting circulation is shortened.