CN112781458A - Safety protection method suitable for blast demolition - Google Patents

Abstract

The invention discloses a safety protection method suitable for blast demolition, which comprises the following steps: (1) covering protection: the covering protection comprises the step of covering and protecting a building floor and an exploded body by using a covering protection layer to prevent flying stones and dust from flying from a cavity at the top of the core cylinder; (2) protection against close body: the near body protection comprises a door and a window which are used for sealing a non-blasting area by using a safety protection device and blocking flying stones and smoke dust; (3) conservative protection: the conservative protection comprises the steps that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of the climbing frame operation platform for protection, so that flying stones are isolated.

Description

Safety protection method suitable for blast demolition

Technical Field

The invention relates to a safety protection method suitable for blast demolition, and belongs to the technical field of building demolition.

Background

In recent years, with the increase of municipal works and traffic engineering, demolition blasting works are more and more, and the demolition blasting needs to determine the overall scheme of demolition blasting according to engineering requirements and the characteristics of the surrounding environment by considering the structural characteristics of buildings.

The individual flying stones and shock waves in the demolition blasting can cause potential safety hazards, dust can fly in the demolition blasting, and the damage of the generated dust to the environment can have great influence on densely populated areas.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides a safety protection method for effectively protecting blasting flyrock, dust, air shock wave and noise.

The technical scheme is as follows: in order to solve the technical problem, the safety protection method suitable for blast demolition comprises the following steps:

(1) covering protection: the covering protection comprises the step of covering and protecting a building floor and an exploded body by using a covering protection layer to prevent flying stones and dust from flying from a cavity at the top of the core cylinder;

(2) protection against close body: the near body protection comprises a door and a window which are used for sealing a non-blasting area by using a safety protection device and blocking flying stones and smoke dust;

(3) conservative protection: the conservative protection comprises the steps that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of the climbing frame operation platform for protection, so that flying stones are isolated.

Furthermore, the safety protection device consists of 5 protection safety layers, wherein the first safety layer is a steel bar net layer, the second safety layer is a high-density flame-retardant foam plate layer, the third safety layer is a steel wire net layer, the fourth safety layer is a glass wool layer, and the fifth safety layer is a thin steel plate layer; splicing openings for splicing are formed in the left side and the right side of the safety protection device; the safety protection device is 2.8m high and 1.5m wide; and the safety protection device is provided with an explosive pore channel and a pressure sensor. The explosive and the pressure sensor are arranged, and when the pressure applied to the pressure sensor exceeds a certain value, the explosive on the invention is subjected to self-explosion to resist shock waves and flying stones generated during the blasting of buildings from flying.

Further, the group of safety protection devices are spliced into a safety protection net through a fixing device, and the safety protection net is used for sealing doors and windows in a non-blasting area.

Furthermore, the covering protection layer is 2 layers of high-fiber curtain nets, and the floor slabs are directly covered through binding iron wires for covering protection.

A method of demolishing a building, comprising the steps of:

a method for dismantling a super high-rise building comprises the following steps: step 1, building a peripheral operation platform of a building: a convenient safety protection frame which has four layers and can move up and down is built on the periphery of a super high-rise building, and the convenient safety protection frame mainly comprises a steel pipe, a baffle, a protective net, hoisting equipment and the like;

step 2, pre-dismantling: taking every two floors as a dismantling unit, dividing the dismantling unit into a first dismantling unit and a second dismantling unit from top to bottom, and so on until the first floor of the building is reached; and then, pre-dismantling the first dismantling unit, and according to a groined principle, not blasting partial upright columns symmetrically reserved in the inner layer of the frame so as to ensure the overall stability of the building body in the blasting process.

Step 3, perforating and charging: dividing a first dismantling unit into a blasting area and a static cutting area, wherein the blasting area is divided into an inner core tube area and a frame inner layer upright post area; the inner-layer upright post of the frame comprises a supporting upright post and a bearing upright post; the upright columns in the inner core tube area and the inner layer upright column area of the frame are divided into concrete upright columns and stiff columns, and the wall body is divided into a common-size shear wall and a common-size shear wall; dividing the inner core barrel area into a group of detonation areas by taking a transverse axis and a longitudinal axis of the inner core barrel area as separation lines, selecting all stand columns positioned on the core barrel main body and support stand columns positioned on the inner layer of the frame as blasting objects, distinguishing common-size shear walls and shear walls according to the blasting objects, drilling blast holes on the blasting objects and placing explosive charges on the common-size shear walls;

step 4, safety protection: lay dustproof and noise reduction pipeline and material equipment in the blasting region, lay protector in blasting region and building body outside and periphery, mainly include:

(1) covering protection: the covering protection comprises the step of covering and protecting a building floor and an exploded body by using a covering protection layer to prevent flying stones and dust from flying from a cavity at the top of the core cylinder;

(2) protection against close body: the near body protection comprises a door and a window which are used for sealing a non-blasting area by using a safety protection device and blocking flying stones and smoke dust;

(3) conservative protection: the conservative protection comprises the steps that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of the climbing frame operation platform for protection, so that flying stones are isolated.

According to the safety protection requirement and the size of a building body, the special safety protection device is designed to have the height and width of 2.8 multiplied by 1.5m, the thickness of 11cm and the weight of about 35kg in consideration of the universality of standard components. The member is composed of 5 layers of protective materials, and the safety protection device is provided with an explosive pore channel and a pressure sensor. The method mainly comprises the following steps:

the 1 st layer is a reinforcing mesh layer, is made of phi 6mm reinforcing steel bars with the transverse and vertical intervals of 10cm and weighs about 17.6 kg;

the 2 nd layer is a high-density flame-retardant foam board layer, the foam board material is flame-retardant phenolic foam, and the volume weight is 40kg/m³5cm in thickness and about 8.4kg in weight;

the 3 rd layer is a steel wire mesh layer with the size of 10 multiplied by 0.6 mm;

the 4 th layer is a glass wool layer with the volume weight of 40kg/m³The glass wool has the thickness of 5cm and the weight of about 8.4 kg;

the 5 th layer is a thin steel plate layer, and a steel plate with the thickness of 0.6mm is selected.

The special safety protection standard component reserves 10cm wide concatenation mouth in both sides, and the concatenation mouth is located two perpendicular limits departments of third layer safety layer, is provided with 5 at least concatenation holes on the concatenation mouth, fixes through fixing device between the concatenation hole. The design of the splicing port can be used for nondestructively disassembling and assembling the protective component in the installation and connection processes, is easy to connect and disassemble, and can realize the reutilization of the invention. The splicing port is composed of 3 layers of protective materials, the number 1-3 layers of materials are formed on one side of the splicing position, and the number 3-5 layers of materials are formed on the other side of the splicing position. 5 holes with the diameter of 15mm are reserved in the splicing openings at the two sides so as to be spliced and fixed subsequently, and the hole distance is 65 cm. After splicing is completed, the spliced part is composed of 6 layers of materials (two steel wire mesh layers). The protective component is not damaged in the installation and connection process, the connection and the disassembly are easy, and the repeated utilization of the protective component can be realized.

And arranging a protection device capable of being spliced to block shock waves at the position of 1-2 m around the blasting area, and protecting flying stones from flying. The size of a single splicing protective device is 60 multiplied by 60cm, and the structural block material consists of 5 layers of protective materials, including a 0.6cm protective net, a 5 cm-thick high-density flame-retardant foam board layer, a 0.6cm protective net, a 5 cm-thick glass wool layer and 0.6cm color steel plates at intervals. The single protection component block is provided with explosives and a pressure sensor, and when the pressure applied to the protection block sensor exceeds a certain value, the explosives on the protection block are subjected to self-explosion to resist shock waves and flying stones generated during the blasting of the building from flying.

The protection device capable of being spliced is formed by hinging and connecting protection blocks capable of being spliced, and after splicing is completed, the cross supporting device is added, so that the overall structural rigidity of the protection device is ensured. The top layer and the side edge of the protection device can be fixed with the environment wall body through hinges, and the bottom protection block can be connected with the universal wheels, so that the protection component can integrally move.

The outer side of the blasting component is directly coated with 2 layers of high-fiber curtain nets and bound by iron wires to serve as a first protective net for flying stone protection.

Step 5, dust fall and noise reduction protection: laying a dust settling and noise reducing device in the blasting area and the static cutting area; in order to reduce the overlarge dust amount in the blasting process, water is sprayed inside the blasting area structure before blasting is started. The peripheral climbing frame is provided with a spraying device, and the spraying water pipe networks are arranged in a transverse, longitudinal and vertical cross way at intervals of 10 m. A layer of canvas covers the upper part of the spraying pipe network. 5 dust concentration parameter detection modules of shower network installation, adopt the light-sensitive principle to carry out dust concentration and detect, spray the water yield according to real-time dust concentration adjustment, the maximize is practiced thrift and is sprayed the water.

And 6, detonating the explosive: setting electronic detonators in the detonation areas divided in the step 3, connecting all the electronic detonators to a blasting bus in a parallel mode, connecting the bus to a special detonator, and detonating according to the detonation sequence by the special detonator;

step 7, after blasting is finished, the slag removing team enters the field to remove slag soil: reform transform into movable rubbish dog-house with elevator well entrance to a cave, scarfing cinder team gets into from not blasting the region through the construction elevator, utilizes the elevator well as the perpendicular transport corridor of dregs, and other floor core section of thick bamboo elevator mouths all use the building block to seal, avoid the dregs to drop a large amount of dusts and the noise of production and protection constructor safety, wet building rubbish in the floor simultaneously, avoid directly throwing into the well with dry rubbish. The shock absorption steel plate slope is arranged at the discharge port of the first layer for shock absorption, and the rubber plate is paved on the shock absorption steel plate, so that the gravitational potential energy can be effectively released, the impact force at the falling point of the material can be buffered, and the functions of safety and environmental protection can be achieved.

Step 8, after slag removal is finished, building a temporary support layer, and cutting, lifting and transferring the top plate structure of the first dismantling unit; specifically, the floor slab is cut off firstly, and then the secondary beam and the main beam are cut off. When the beam structure is cut, the load of the beam body, the load of the supporting structure, the stability of the lower beam body and the floor slab are checked and calculated according to the beam body structure, the cutting surface position and the lifting point position, and the support is reasonably distributed. During cutting, the supporting points need to be tightly attached to the lower bottom surface of the beam body, the beam body can stably fall on the support after being separated, the cut block body needs to be lifted out of the support frame in time, and the block body is forbidden to be placed on the support frame for a long time. According to the bearable load of the tower crane, the quality of the split component is controlled, so that the lifting safety is ensured. The beam member hoisting holes are not less than 4, and the distance from the two ends of the beam plate is 1/6 of the beam length and is not less than 600 mm.

Step 9, carrying out static cutting dismantling and hoisting and transferring on the static cutting area; when the wall body is cut, supporting scaffold for preventing the wall body from inclining needs to be erected on the periphery. In order to prevent the cutting block from deviating to influence cutting, a rope threading hole needs to be drilled in advance before cutting, and a steel pipe is installed through the rope threading hole to be connected and fixed with other undetached wall bodies, so that the effect of balancing the demolition block is achieved. During hoisting, the number of the hoisting holes of the shear wall member is not less than two, the diameter of each hoisting hole is 108mm, the distance from the free surface at the top end is not less than 800mm, and the distance from the 1/6 position of the horizontal length of the lateral free surface is not less than 400 mm.

When the column body is cut, the column body structure units need to be divided, and the weight of a single block after the block division is necessarily smaller than the rated lifting capacity of the tower crane. When the frame column is cut, the steel pipe support is arranged in the lateral direction of the column to prevent the column from being overturned, and then cutting construction is carried out. After cutting, a diamond thin-wall drilling machine is used for drilling hoisting holes, steel bars are inserted into the two sides of the frame column in a drilling mode, 4 hoisting holes with the diameter of 108mm need to be drilled in each concrete plate after the column body is cut, and a hoisting steel wire rope penetrates through the column body to conduct hoisting operation.

And step 10, finishing the slag removal procedure handover, transferring to a second dismantling unit, constructing according to the construction circulation mode until the ground is one floor, and finishing.

Further, the pre-demolition in the step 2 comprises demolishing all non-bearing steam pressurized concrete walls and doors and windows in the blasting area, and cutting off water, electricity, gas, heat supply, communication pipelines and metal garbage channels.

Further, the perforating charge of the concrete column in the step 3 comprises the following steps:

(1) two longitudinal rows of through holes are arranged on the longitudinal section of the concrete column, the distance of central axes of the two longitudinal rows of through holes is 40cm, the height difference of the through holes corresponding to each other on the two longitudinal rows is 50cm, and the depth of a pore passage of each through hole is as follows:

L＝B-δ/2

wherein, δ is the thickness of the upright column; b is the maximum side length of the upright column;

(2) explosive packages and detonating cords are distributed in the pore passage at intervals, the interval distance of the explosive packages is 0.3 m, and a digital detonator and a water bag are sequentially arranged at the outlet of the pore passage from inside to outside and are stuffed; net length of blast hole after charging₁The requirements are as follows:

L₁≥(1.1～1.2)W

wherein W is the minimum resistance line and is 35 mm.

Further, the perforating charge of the stiff columns in step 3 comprises the following steps:

s1, arranging two longitudinal rows of through holes on the longitudinal section of the stiff column, wherein the distance of central axes of the two longitudinal rows of through holes is 40cm, the height difference of the through holes corresponding to each other on the two longitudinal rows is 50cm, and the depth of pore channels of the through holes is as follows:

L＝B-δ/2

wherein, δ is the thickness of the upright column; and B is the maximum side length of the upright column.

S2, arranging explosive bags and detonating cords in the pore channels at intervals, wherein the interval distance between the explosive bags is 0.3 m, and sequentially installing digital detonators and water bags at the outlets of the pore channels and filling; net length of blast hole after charging₁The requirements are as follows:

L₁≥(1.1～1.2)W

wherein W is the minimum resistance line and is half of the length of the short side of the stiff column;

s3, the stiff columns contain internal steel, inclined hole channels are arranged at the positions adjacent to the internal steel, and linear energy gathering cutters are arranged in the inclined hole channels; the inclined pore passage consists of two pore passages, the longitudinal sections of the two pore passages are in a V shape, the tips of the V-shaped pore passages are at the inner steel, and the inlets and the outlets of the V-shaped pore passages are on the outer surface of the stiff column; an included angle is formed between two duct channels of the V-shaped duct channel, and the included angle ranges from 30 degrees to 45 degrees.

Further, the perforating charge of the shear wall in the step 3 comprises the following steps:

firstly, digging an arch-shaped wall hole on a shear wall;

secondly, two through holes are formed in the top and the bottom of the shear wall, the distance between the top hole and the upper floor slab is 0.5m, the distance between the bottom hole and the lower floor slab is 0.5m, and X-shaped energy gathering cutters are arranged in the top hole and the bottom hole;

a group of horizontal pore channels are arranged between the top pore channel and the bottom pore channel, a part of horizontal pore channels enter from the left wall body, and a horizontal pore channel entering from the right wall body is arranged between every two adjacent horizontal pore channels entering from the left side;

fourthly, explosive packages and detonating cords are arranged in the horizontal pore channels at intervals, the interval distance of the explosive packages is 0.3 m, and digital detonators and water bags are sequentially arranged at the outlet of the pore channels from inside to outside and are stuffed; the net blocking length L1 after the blast hole is charged needs to satisfy the following conditions:

L1≥(1.1～1.2)W

wherein W is the minimum resistance line, and is half of the wall thickness of the section of the shear wall.

Further, the perforating and charging of the common-size shear wall in the step 3 comprises the following steps:

A. two through holes are formed in the top and the bottom of the common-size shear wall, the distance between the top hole and the upper floor slab is 0.5m, the distance between the bottom hole and the lower floor slab is 0.5m, and X-shaped energy gathering cutters are arranged in the top hole and the bottom hole;

B. two sides of a common-size shear wall are respectively provided with a W-shaped double-layer energy gathering cutter which is fixed through a limiting plate; when blasting demolition is carried out, the lower layer of energy gathering cutters generate blade-shaped jet flow firstly, the blade-shaped jet flow acts on the concrete of the shear wall with the common size to crush the surface of the concrete of the structure, and then the upper layer of cutters generate the blade-shaped jet flow to further cut the reinforcing steel bars inside the shear wall with the common size.

Further, the detonation sequence in step 6 is to divide the detonation zone into 12 detonation units, wherein 8 detonation units form an internal zone and are divided into two rows, the serial numbers of the first row of units are respectively No. 5, No. 3, No. 1 and No. 8 from left to right, and the serial numbers of the second row of units are respectively No. 7, No. 2, No. 4 and No. 6 from left to right; the other 4 initiation units are respectively positioned at the upper left corner, the upper right corner, the lower left corner and the lower right corner of the internal area, the upper left corner is numbered as 9, the upper right corner is numbered as 11, the lower left corner is numbered as 12, and the lower right corner is numbered as 10; the initiation sequence is in the sequence of No. 1 to No. 12, and the delayed initiation is carried out in sequence; when the detonation of the detonation unit on the upper layer is finished, the detonation unit entering the lower layer starts to detonate until all the detonation units are finished; the delayed detonation method is characterized in that each detonation unit is detonated with a delay of 0.5s compared with the last detonation unit, and the interval time between the detonation of the upper floor and the detonation of the lower floor is 2 s. The delayed detonation method is characterized in that each detonation unit is detonated with a delay of 0.5s compared with the last detonation unit, and the interval time between the detonation of the upper floor and the detonation of the lower floor is 2 s.

Further, the explosive quantity calculation method in the step 3 is according to the savofsky formula, and the allowable explosive quantity calculation formula of the maximum single initiation unit obtained after deformation is as follows:

Q_max＝(V_c/K)^3/α×R³

in the formula, Qmax is the maximum single-stage explosive quantity, kg;

vc-the safe allowable particle vibration speed of the protected object, cm/s.

R is the distance from the blasting central point to the protected target, m;

K. alpha is coefficient and earthquake wave attenuation index related to blasting terrain, geological condition and the like, and the specific numerical values of K and alpha can be obtained by table lookup.

Further, the safety protection in step 4 is classified into (1) coverage protection: the covering protection comprises the steps of covering and protecting a building floor slab and an exploded body by using a covering protection layer, and preventing flying stones and dust from flying from a cavity at the top of the core cylinder; (2) protection against close body: the close body protection comprises the steps of utilizing a safety protection device to seal doors and windows in a non-blasting area and block flying stones and smoke dust; (3) conservative protection: conservative protection includes that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of a climbing frame operation platform for protection to isolate flying stones.

Further, the static force cutting method in the step 8 is as follows:

a. after the blasting and slag removal of the building are finished, building a temporary support frame, and dividing the part needing to be cut for dismantling the unit layer into a top plate structure, a wall body structure and a column body structure;

b. the cutting of the top plate structure is carried out according to the sequence of firstly cutting the floor slab, then cutting the secondary beam and then cutting the main beam;

c. when the main beam and the secondary beam are cut, the load of the beam body and the load of the support frame on the layer are checked and calculated according to the structure of the beam body, the position of the cutting surface and the position of the lifting point, and the stability of the beam body and the floor slab on the lower layer is ensured;

d. the support frame is tightly attached to the lower surfaces of the main beam body and the secondary beam body, so that the beams can fall on the support frame after being separated; the cut block is lifted away from the support frame in time and is transported out of the building;

e. before the wall structure is cut, a supporting scaffold is erected around the wall structure to prevent the wall from inclining, a rope penetrating hole is drilled in the wall, and the rope penetrating hole is fixedly connected with other undetached walls through a fixing structure;

f. when the block body is hoisted after cutting, at least two hoisting holes are formed in the block body;

g. the cutting of the column body structure firstly blocks the column body, and the weight of a single block of the block is necessarily smaller than the rated lifting capacity of the tower crane.

The invention adopts the means of 'implosion and exo-excision', realizes the complementary advantages of the efficacy and the safety of two operation modes, the inner layer blasting has good efficacy, and the outer layer cutting has double safety functions. (2) And during blasting operation, a part of shear walls and frame layer stand columns in the core barrel are reserved as supports, the floor and the connecting beam do not collapse after blasting, the whole structure of the unit layer is unchanged, the safety of the outer wall body is protected, and the outer wall body is used as a protective barrier for blasting flying stones, shock waves, noise and dust. (3) The advanced blasting equipment is selected, the micro-differential control blasting technology is applied, the blast hole explosive quantity and the detonation time difference are accurately designed, the accurate blasting effect is realized, the blasting vibration and the impact wave are controlled to influence the self structure and the surrounding environment of the building, and the blasting safety, the high efficiency and the green environmental protection are realized through the scientific technical design and the novel protection design.

Has the advantages that: (1) blasting safety protection is an important ring in blasting demolition. The characteristics of large blasting main body, tight construction period, high safety and environmental protection requirements and the like are considered; the safety protection device in the safety protection method has the functions of blocking flying stones and isolating noise and dust, and has the characteristics of convenience and quickness in assembly and disassembly. (2) The safety protection method provided by the invention can obviously improve the construction efficiency, accelerate the construction period and enhance the safety protection effect, and the safety protection effect is obvious through grading protection on different buildings.

Drawings

FIG. 1 is a schematic diagram of coverage protection in an embodiment of the present invention;

FIG. 2 is a schematic diagram of the near body shield of the embodiment of the present invention;

FIG. 3 is a diagram illustrating conservative protection in an embodiment of the present invention;

Detailed Description

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

Example 1

A safety protection method suitable for blast demolition comprises the following steps:

(1) covering protection: the covering protection comprises the step of covering and protecting a building floor and an exploded body by using a covering protection layer to prevent flying stones and dust from flying from a cavity at the top of the core cylinder;

(2) protection against close body: the near body protection comprises a door and a window which are used for sealing a non-blasting area by using a safety protection device and blocking flying stones and smoke dust;

(3) conservative protection: the conservative protection comprises the steps that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of the climbing frame operation platform for protection, so that flying stones are isolated.

The safety protection device consists of 5 protection safety layers, wherein the first safety layer is a steel bar net layer, the second safety layer is a high-density flame-retardant foam board layer, the third safety layer is a steel wire net layer, the fourth safety layer is a glass wool layer, and the fifth safety layer is a thin steel plate layer; splicing openings for splicing are formed in the left side and the right side of the safety protection device; the safety protection device is 2.8m high and 1.5m wide; and the safety protection device is provided with an explosive pore channel and a pressure sensor. The explosive and the pressure sensor are arranged, and when the pressure applied to the pressure sensor exceeds a certain value, the explosive on the invention is subjected to self-explosion to resist shock waves and flying stones generated during the blasting of buildings from flying. And splicing the group of safety protection devices into a safety protection net through a fixing device, and sealing the safety protection net into doors and windows in a non-blasting area. The covering protection layer is 2 layers of high-fiber curtain nets and directly coats the floor slab for covering protection through iron wire binding.

Example 2

A method for dismantling a super high-rise building comprises the following steps:

step 1, building a peripheral operation platform of a building: a convenient safety protection frame which has four layers and can move up and down is built on the periphery of a super high-rise building, and the convenient safety protection frame mainly comprises a steel pipe, a baffle, a protective net, hoisting equipment and the like;

step 2, pre-dismantling: taking every two floors as a dismantling unit, dividing the dismantling unit into a first dismantling unit and a second dismantling unit from top to bottom, and so on until the first floor of the building is reached; and then, pre-dismantling the first dismantling unit, and according to a groined principle, not blasting partial upright columns symmetrically reserved in the inner layer of the frame so as to ensure the overall stability of the building body in the blasting process.

Step 3, perforating and charging: dividing a first dismantling unit into a blasting area and a static cutting area, wherein the blasting area is divided into an inner core tube area and a frame inner layer upright post area; the inner-layer upright post of the frame comprises a supporting upright post and a bearing upright post; the upright columns in the inner core tube area and the inner layer upright column area of the frame are divided into concrete upright columns and stiff columns, and the wall body is divided into a common-size shear wall and a common-size shear wall; dividing the inner core barrel area into a group of detonation areas by taking a transverse axis and a longitudinal axis of the inner core barrel area as separation lines, selecting all stand columns positioned on the core barrel main body and support stand columns positioned on the inner layer of the frame as blasting objects, distinguishing common-size shear walls and shear walls according to the blasting objects, drilling blast holes on the blasting objects and placing explosive charges on the common-size shear walls;

step 4, safety protection: lay dustproof and noise reduction pipeline and material equipment in the blasting region, lay protector in blasting region and building body outside and periphery, mainly include:

(1) covering protection: the covering protection comprises the step of covering and protecting a building floor and an exploded body by using a covering protection layer to prevent flying stones and dust from flying from a cavity at the top of the core cylinder;

(2) protection against close body: the near body protection comprises a door and a window which are used for sealing a non-blasting area by using a safety protection device and blocking flying stones and smoke dust;

(3) conservative protection: the conservative protection comprises the steps that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of the climbing frame operation platform for protection, so that flying stones are isolated.

According to the safety protection requirement and the size of a building body, the special safety protection device is designed to have the height and width of 2.8 multiplied by 1.5m, the thickness of 11cm and the weight of about 35kg in consideration of the universality of standard components. The member is composed of 5 layers of protective materials, and the safety protection device is provided with an explosive pore channel and a pressure sensor. The method mainly comprises the following steps:

the 1 st layer is a reinforcing mesh layer, is made of phi 6mm reinforcing steel bars with the transverse and vertical intervals of 10cm and weighs about 17.6 kg;

the 2 nd layer is a high-density flame-retardant foam board layer, the foam board material is flame-retardant phenolic foam, and the volume weight is 40kg/m³Thickness of5cm, weighing about 8.4 kg;

the 3 rd layer is a steel wire mesh layer with the size of 10 multiplied by 0.6 mm;

the 4 th layer is a glass wool layer with the volume weight of 40kg/m³The glass wool has the thickness of 5cm and the weight of about 8.4 kg;

the 5 th layer is a thin steel plate layer, and a steel plate with the thickness of 0.6mm is selected.

The special safety protection standard component reserves 10cm wide concatenation mouth in both sides, and the concatenation mouth is located two perpendicular limits departments of third layer safety layer, is provided with 5 at least concatenation holes on the concatenation mouth, fixes through fixing device between the concatenation hole. The design of the splicing port can be used for nondestructively disassembling and assembling the protective component in the installation and connection processes, is easy to connect and disassemble, and can realize the reutilization of the invention. The splicing port is composed of 3 layers of protective materials, the number 1-3 layers of materials are formed on one side of the splicing position, and the number 3-5 layers of materials are formed on the other side of the splicing position. 5 holes with the diameter of 15mm are reserved in the splicing openings at the two sides so as to be spliced and fixed subsequently, and the hole distance is 65 cm. After splicing is completed, the spliced part is composed of 6 layers of materials (two steel wire mesh layers). The protective component is not damaged in the installation and connection process, the connection and the disassembly are easy, and the repeated utilization of the protective component can be realized.

And arranging a protection device capable of being spliced to block shock waves at the position of 1-2 m around the blasting area, and protecting flying stones from flying. The size of a single splicing protective device is 60 multiplied by 60cm, and the structural block material consists of 5 layers of protective materials, including a 0.6cm protective net, a 5 cm-thick high-density flame-retardant foam board layer, a 0.6cm protective net, a 5 cm-thick glass wool layer and 0.6cm color steel plates at intervals. The single protection component block is provided with explosives and a pressure sensor, and when the pressure applied to the protection block sensor exceeds a certain value, the explosives on the protection block are subjected to self-explosion to resist shock waves and flying stones generated during the blasting of the building from flying.

The protection device capable of being spliced is formed by hinging and connecting protection blocks capable of being spliced, and after splicing is completed, the cross supporting device is added, so that the overall structural rigidity of the protection device is ensured. The top layer and the side edge of the protection device can be fixed with the environment wall body through hinges, and the bottom protection block can be connected with the universal wheels, so that the protection component can integrally move.

The outer side of the blasting component is directly coated with 2 layers of high-fiber curtain nets and bound by iron wires to serve as a first protective net for flying stone protection.

Step 5, dust fall and noise reduction protection: laying a dust settling and noise reducing device in the blasting area and the static cutting area; in order to reduce the overlarge dust amount in the blasting process, water is sprayed inside the blasting area structure before blasting is started. The peripheral climbing frame is provided with a spraying device, and the spraying water pipe networks are arranged in a transverse, longitudinal and vertical cross way at intervals of 10 m. A layer of canvas covers the upper part of the spraying pipe network. 5 dust concentration parameter detection modules of shower network installation, adopt the light-sensitive principle to carry out dust concentration and detect, spray the water yield according to real-time dust concentration adjustment, the maximize is practiced thrift and is sprayed the water.

And 6, detonating the explosive: setting electronic detonators in the detonation areas divided in the step 3, connecting all the electronic detonators to a blasting bus in a parallel mode, connecting the bus to a special detonator, and detonating according to the detonation sequence by the special detonator;

step 7, after blasting is finished, the slag removing team enters the field to remove slag soil: reform transform into movable rubbish dog-house with elevator well entrance to a cave, scarfing cinder team gets into from not blasting the region through the construction elevator, utilizes the elevator well as the perpendicular transport corridor of dregs, and other floor core section of thick bamboo elevator mouths all use the building block to seal, avoid the dregs to drop a large amount of dusts and the noise of production and protection constructor safety, wet building rubbish in the floor simultaneously, avoid directly throwing into the well with dry rubbish. The shock absorption steel plate slope is arranged at the discharge port of the first layer for shock absorption, and the rubber plate is paved on the shock absorption steel plate, so that the gravitational potential energy can be effectively released, the impact force at the falling point of the material can be buffered, and the functions of safety and environmental protection can be achieved.

Step 8, after slag removal is finished, building a temporary support layer, and cutting, lifting and transferring the top plate structure of the first dismantling unit; specifically, the floor slab is cut off firstly, and then the secondary beam and the main beam are cut off. When the beam structure is cut, the load of the beam body, the load of the supporting structure, the stability of the lower beam body and the floor slab are checked and calculated according to the beam body structure, the cutting surface position and the lifting point position, and the support is reasonably distributed. During cutting, the supporting points need to be tightly attached to the lower bottom surface of the beam body, the beam body can stably fall on the support after being separated, the cut block body needs to be lifted out of the support frame in time, and the block body is forbidden to be placed on the support frame for a long time. According to the bearable load of the tower crane, the quality of the split component is controlled, so that the lifting safety is ensured. The beam member hoisting holes are not less than 4, and the distance from the two ends of the beam plate is 1/6 of the beam length and is not less than 600 mm.

Step 9, carrying out static cutting dismantling and hoisting and transferring on the static cutting area; when the wall body is cut, supporting scaffold for preventing the wall body from inclining needs to be erected on the periphery. In order to prevent the cutting block from deviating to influence cutting, a rope threading hole needs to be drilled in advance before cutting, and a steel pipe is installed through the rope threading hole to be connected and fixed with other undetached wall bodies, so that the effect of balancing the demolition block is achieved. During hoisting, the number of the hoisting holes of the shear wall member is not less than two, the diameter of each hoisting hole is 108mm, the distance from the free surface at the top end is not less than 800mm, and the distance from the 1/6 position of the horizontal length of the lateral free surface is not less than 400 mm.

When the column body is cut, the column body structure units need to be divided, and the weight of a single block after the block division is necessarily smaller than the rated lifting capacity of the tower crane. When the frame column is cut, the steel pipe support is arranged in the lateral direction of the column to prevent the column from being overturned, and then cutting construction is carried out. After cutting, a diamond thin-wall drilling machine is used for drilling hoisting holes, steel bars are inserted into the two sides of the frame column in a drilling mode, 4 hoisting holes with the diameter of 108mm need to be drilled in each concrete plate after the column body is cut, and a hoisting steel wire rope penetrates through the column body to conduct hoisting operation.

And step 10, finishing the slag removal procedure handover, transferring to a second dismantling unit, constructing according to the construction circulation mode until the ground is one floor, and finishing.

And the pre-demolition in the step 2 comprises demolishing all non-bearing steam pressurized concrete walls and doors and windows in the blasting area, and cutting off water, electricity, gas, heat supply, communication pipelines and metal garbage channels.

The perforating and charging of the concrete upright column in the step 3 comprises the following steps:

(1) two longitudinal rows of through holes are arranged on the longitudinal section of the concrete column, the distance of central axes of the two longitudinal rows of through holes is 40cm, the height difference of the through holes corresponding to each other on the two longitudinal rows is 50cm, and the depth of a pore passage of each through hole is as follows:

L＝B-δ/2

wherein, δ is the thickness of the upright column; b is the maximum side length of the upright column;

(2) explosive packages and detonating cords are distributed in the pore passage at intervals, the interval distance of the explosive packages is 0.3 m, and a digital detonator and a water bag are sequentially arranged at the outlet of the pore passage from inside to outside and are stuffed; net length of blast hole after charging₁The requirements are as follows:

L₁≥(1.1～1.2)W

wherein W is the minimum resistance line and is 35 mm.

The perforating and charging of the stiff column in the step 3 comprises the following steps:

s1, arranging two longitudinal rows of through holes on the longitudinal section of the stiff column, wherein the distance of central axes of the two longitudinal rows of through holes is 40cm, the height difference of the through holes corresponding to each other on the two longitudinal rows is 50cm, and the depth of pore channels of the through holes is as follows:

L＝B-δ/2

wherein, δ is the thickness of the upright column; and B is the maximum side length of the upright column.

S2, arranging explosive bags and detonating cords in the pore channels at intervals, wherein the interval distance between the explosive bags is 0.3 m, and sequentially installing digital detonators and water bags at the outlets of the pore channels and filling; net length of blast hole after charging₁The requirements are as follows:

L₁≥(1.1～1.2)W

wherein W is the minimum resistance line and is half of the length of the short side of the stiff column;

s3, the stiff columns contain internal steel, inclined hole channels are arranged at the positions adjacent to the internal steel, and linear energy gathering cutters are arranged in the inclined hole channels; the inclined pore passage consists of two pore passages, the longitudinal sections of the two pore passages are in a V shape, the tips of the V-shaped pore passages are at the inner steel, and the inlets and the outlets of the V-shaped pore passages are on the outer surface of the stiff column; an included angle is formed between two duct channels of the V-shaped duct channel, and the included angle ranges from 30 degrees to 45 degrees.

The perforating and charging of the shear wall in the step 3 comprises the following steps:

firstly, digging an arch-shaped wall hole on a shear wall;

secondly, two through holes are formed in the top and the bottom of the shear wall, the distance between the top hole and the upper floor slab is 0.5m, the distance between the bottom hole and the lower floor slab is 0.5m, and X-shaped energy gathering cutters are arranged in the top hole and the bottom hole;

a group of horizontal pore channels are arranged between the top pore channel and the bottom pore channel, a part of horizontal pore channels enter from the left wall body, and a horizontal pore channel entering from the right wall body is arranged between every two adjacent horizontal pore channels entering from the left side;

fourthly, explosive packages and detonating cords are arranged in the horizontal pore channels at intervals, the interval distance of the explosive packages is 0.3 m, and digital detonators and water bags are sequentially arranged at the outlet of the pore channels from inside to outside and are stuffed; the net blocking length L1 after the blast hole is charged needs to satisfy the following conditions:

L1≥(1.1～1.2)W

wherein W is the minimum resistance line, and is half of the wall thickness of the section of the shear wall.

The perforating and charging of the shear wall with the common size in the step 3 comprises the following steps:

A. two through holes are formed in the top and the bottom of the common-size shear wall, the distance between the top hole and the upper floor slab is 0.5m, the distance between the bottom hole and the lower floor slab is 0.5m, and X-shaped energy gathering cutters are arranged in the top hole and the bottom hole;

B. two sides of a common-size shear wall are respectively provided with a W-shaped double-layer energy gathering cutter which is fixed through a limiting plate; when blasting demolition is carried out, the lower layer of energy gathering cutters generate blade-shaped jet flow firstly, the blade-shaped jet flow acts on the concrete of the shear wall with the common size to crush the surface of the concrete of the structure, and then the upper layer of cutters generate the blade-shaped jet flow to further cut the reinforcing steel bars inside the shear wall with the common size.

The detonation sequence in the step 6 is to divide the detonation zone into 12 detonation units, wherein 8 detonation units form an internal zone and are divided into two rows, the serial numbers of the first row of units are respectively No. 5, No. 3, No. 1 and No. 8 from left to right, and the serial numbers of the second row of units are respectively No. 7, No. 2, No. 4 and No. 6 from left to right; in addition, 4 initiation units are respectively positioned at the upper left corner, the upper right corner, the lower left corner and the lower right corner of the internal area, the upper left corner is numbered as 9, the upper right corner is numbered as 11, the lower left corner is numbered as 12, and the lower right corner is numbered as 10; the initiation sequence is in the sequence of No. 1 to No. 12, and the delayed initiation is carried out in sequence; when the initiation of the initiation unit on the upper layer is finished, the initiation unit entering the lower layer starts initiation until all initiation units are finished; the delayed detonation method is characterized in that each detonation unit is detonated with a delay of 0.5s compared with the last detonation unit, and the interval time between the detonation of an upper floor and the detonation of a lower floor is 2 s. The delayed detonation method is characterized in that each detonation unit is detonated with a delay of 0.5s compared with the last detonation unit, and the interval time between the detonation of the upper floor and the detonation of the lower floor is 2 s.

The explosive quantity calculation method in the step 3 is that according to the Sadow-fusi formula, the allowable explosive quantity calculation formula of the maximum single initiation unit obtained after deformation is as follows:

Q_max＝(V_c/K)^3/α×R³

in the formula, Qmax is the maximum single-stage explosive quantity, kg;

vc-the safe allowable particle vibration speed of the protected object, cm/s.

R is the distance from the blasting central point to the protected target, m;

K. alpha is coefficient and earthquake wave attenuation index related to blasting terrain, geological condition and the like, and the specific numerical values of K and alpha can be obtained by table lookup.

The safety protection in the step 4 is divided into (1) coverage protection: the covering protection comprises the steps that a building floor and an exploded body are covered and protected by a covering protection layer, and flying stones and dust are prevented from flying from a cavity at the top of the core barrel; (2) protection against close body: the close body protection comprises the steps of utilizing a safety protection device to seal doors and windows in a non-blasting area and block flying stones and smoke dust; (3) conservative protection: conservative protection includes that a damping ditch is arranged at the outer side of a building body, and two layers of steel wire meshes are arranged at the periphery of a climbing frame operation platform for protection, so that flying stones are isolated.

The static force cutting method in the step 8 comprises the following steps:

a. after the blasting and slag removal of the building are finished, building a temporary support frame, and dividing the part needing to be cut for dismantling the unit layer into a top plate structure, a wall body structure and a column body structure;

b. the cutting of the top plate structure is carried out according to the sequence of firstly cutting the floor slab, then cutting the secondary beam and then cutting the main beam;

c. when the main beam and the secondary beam are cut, the load of the beam body and the load of the support frame on the layer are checked and calculated according to the structure of the beam body, the position of the cutting surface and the position of the lifting point, and the stability of the beam body and the floor slab on the lower layer is ensured;

d. the support frame is tightly attached to the lower surfaces of the main beam body and the secondary beam body, so that the beams can fall on the support frame after being separated; the cut block is lifted away from the support frame in time and is transported out of the building;

e. before the wall structure is cut, a supporting scaffold is erected around the wall structure to prevent the wall from inclining, a rope penetrating hole is drilled in the wall, and the rope penetrating hole is fixedly connected with other undetached walls through a fixing structure;

f. when the block body is hoisted after cutting, at least two hoisting holes are formed in the block body;

g. the cutting of the column body structure firstly blocks the column body, and the weight of a single block of the block is necessarily smaller than the rated lifting capacity of the tower crane.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims (5)

1. A safety protection method suitable for blast demolition is characterized by comprising the following steps:

(1) covering protection: the covering protection comprises the step of covering and protecting a building floor and an exploded body by using a covering protection layer to prevent flying stones and dust from flying from a cavity at the top of the core cylinder;

(2) protection against close body: the near body protection comprises a door and a window which are used for sealing a non-blasting area by using a safety protection device and blocking flying stones and smoke dust;

(3) conservative protection: the conservative protection comprises the steps that a damping ditch is arranged on the outer side of a building body, and two layers of steel wire meshes are arranged on the periphery of the climbing frame operation platform for protection, so that flying stones are isolated.

2. The method of claim 1, wherein the safety protection device comprises 5 layers of protective safety layers, the first layer is a steel mesh layer, the second layer is a high-density flame-retardant foam board layer, the third layer is a steel mesh layer, the fourth layer is a glass wool layer, and the fifth layer is a thin steel plate layer; splicing openings for splicing are formed in the left side and the right side of the safety protection device; the safety protection device is 2.8m high and 1.5m wide; and the safety protection device is provided with an explosive pore channel and a pressure sensor.

3. The safety protection method suitable for demolition blasting according to claim 2, wherein a group of the safety protection devices are spliced into a safety protection net through a fixing device, and the safety protection net is used for sealing doors and windows of a non-blasting area.

4. A safety protection method suitable for use in blast demolition as claimed in claim 3, wherein the said protective cover is 2 layers of high fiber curtain net, which is covered and protected by tying iron wire to cover the floor directly.

5. A method of demolishing a building, comprising: step 1, building a peripheral operation platform of a building: constructing a convenient and fast safety protection frame which has four layers of height and can move up and down on the periphery of the super high-rise building;

step 2, pre-dismantling: taking every two floors as a dismantling unit, dividing the dismantling unit into a first dismantling unit and a second dismantling unit from top to bottom, and so on until the first floor of the building is reached; then, pre-dismantling the first dismantling unit;

step 3, perforating and charging: dividing the first dismantling unit into a blasting area and a static cutting area, wherein the blasting area is divided into an inner core cylinder area and a frame inner layer upright area; the inner-layer upright post of the frame comprises a supporting upright post and a bearing upright post; the upright columns in the inner core tube area and the inner layer upright column area of the frame are divided into concrete upright columns and stiff columns, and the wall body is divided into a common-size shear wall and a common-size shear wall; dividing the inner core barrel area into a group of detonation areas by taking the transverse axis and the longitudinal axis of the inner core barrel area as separation lines, selecting all stand columns positioned on the core barrel main body and support stand columns positioned on the inner layer of the frame as blasting objects, distinguishing the blasting objects according to the blasting objects, namely concrete stand columns and stiff columns, common-size shear walls and shear walls, drilling blast holes on the blasting objects and placing explosive charges on the shearing walls;

step 4, safety protection: comprising the safety protection method according to claim 4;

step 5, dust fall and noise reduction protection: laying a dust settling and noise reducing device in the blasting area and the static cutting area;

and 6, detonating the explosive: setting electronic detonators in the detonation areas divided in the step 3, connecting all the electronic detonators to a blasting bus in a parallel mode, connecting the bus to a special detonator, and detonating according to the detonation sequence through the special detonator; the detonation sequence is that the detonation zone is divided into 12 detonation units, wherein 8 detonation units form an internal zone and are divided into two rows, the serial numbers of the first row of units are respectively No. 5, No. 3, No. 1 and No. 8 from left to right, and the serial numbers of the second row of units are respectively No. 7, No. 2, No. 4 and No. 6 from left to right; the other 4 initiation units are respectively positioned at the upper left corner, the upper right corner, the lower left corner and the lower right corner of the internal area, the upper left corner is numbered as 9, the upper right corner is numbered as 11, the lower left corner is numbered as 12, and the lower right corner is numbered as 10; the initiation sequence is in the sequence of No. 1 to No. 12, and the delayed initiation is carried out in sequence; when the detonation of the detonation unit on the upper layer is finished, the detonation unit entering the lower layer starts to detonate until all the detonation units are finished; the delayed detonation method is characterized in that each detonation unit is detonated with a delay of 0.5s compared with the last detonation unit, and the interval time between the detonation of the upper floor and the detonation of the lower floor is 2 s.

Step 7, after blasting is finished, the slag removing team enters the field to remove slag soil: the opening of the elevator shaft is reformed into a movable garbage feeding opening, a slag removing team enters from an unexploded area through a construction elevator, and the elevator shaft is used as a vertical muck transportation channel;

step 8, after slag removal is finished, building a temporary support layer, and carrying out static cutting and lifting transfer on a top plate structure of the first dismantling unit;

step 9, carrying out static cutting dismantling and hoisting and transferring on the static cutting area; the static force cutting method comprises the following steps:

a. after the blasting and slag removal of the building are finished, building a temporary support frame, and dividing the part needing to be cut for dismantling the unit layer into a top plate structure, a wall body structure and a column body structure;

b. the roof structure is cut according to the sequence of cutting the floor slab, the secondary beam and the main beam;

c. when the main beam and the secondary beam are cut, the load of the beam body and the load of the support frame on the layer are checked and calculated according to the structure of the beam body, the position of the cutting surface and the position of the lifting point, and the stability of the beam body and the floor on the lower layer is ensured;

d. the support frame is tightly attached to the lower surfaces of the main beam body and the secondary beam body, so that the beams can fall on the support frame after being separated; the cut block is lifted away from the support frame in time and is transported out of the building;

e. before the wall body structure is cut, a supporting scaffold is erected around the wall body structure to prevent the wall body from inclining, a rope penetrating hole is drilled in the wall body, and the rope penetrating hole is fixedly connected with other undetached wall bodies through a fixing structure;

f. when the block body is hoisted after cutting, at least two hoisting holes are formed in the block body;

g. the cutting of the column body structure firstly blocks the column body, and the weight of a single block of the block is necessarily smaller than the rated lifting capacity of the tower crane.

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