阅读说明：本技术 一种建筑物***拆除方法 (Blasting demolition method for building ) 是由 费鸿禄 钱起飞 杨智广 蒋安俊 何文斌 孙晓宇 张广贝 罗婷 刘雨 关福晨 于 2019-09-11 设计创作，主要内容包括：一种建筑物爆破拆除方法属于爆破拆除技术领域,尤其涉及一种建筑物爆破拆除方法。本发明提供一种内收降层建筑物爆破拆除方法。本发明包括以下步骤：1)拆除待爆高层建筑物内部的管线、附属设施；2)在梁与框架柱节点位置的楼板、墙体上打孔,将钢绳一端穿过孔洞缠绕在梁与框架柱节点位置处,用螺栓和夹具固定好,将另一端下放至楼板上；3)将待爆楼层层高范围内部的墙体、楼板、次梁、内部框架柱按从上往下、从外往内的顺序依次破碎拆除；4)机械拆除待爆楼层层高范围内的外墙,仅保留不小于外侧框架柱炸高的一段外墙；5)机械切断待爆楼层层高范围内与外侧框架柱相连的横向、纵向联系主梁；钻孔、装药、连接起爆网路。(a building blasting demolition method belongs to the technical field of blasting demolition, and particularly relates to a building blasting demolition method. The invention provides a blasting demolition method for an adduction landing building. The invention comprises the following steps: 1) dismantling pipelines and auxiliary facilities inside a high-rise building to be exploded; 2) punching holes on a floor slab and a wall body at the positions of the joints of the beam and the frame column, enabling one end of a steel rope to penetrate through the holes to be wound at the positions of the joints of the beam and the frame column, fixing the steel rope by using bolts and a clamp, and lowering the other end of the steel rope onto the floor slab; 3) sequentially crushing and dismantling a wall, a floor slab, a secondary beam and an internal frame column in the storey height range of the storey to be exploded from top to bottom and from outside to inside; 4) mechanically removing the outer wall in the storey height range of the storey to be exploded, and only reserving a section of outer wall which is not smaller than the explosion height of the outer frame column; 5) mechanically cutting off transverse and longitudinal connection main beams connected with the outer frame columns within the storey height range of the storey to be exploded; drilling, charging and connecting with a detonating network.)

1. A building blasting demolition method is characterized by comprising the following steps:

1) dismantling pipelines and auxiliary facilities inside a high-rise building to be exploded;

2) Punching holes on a floor slab and a wall body at the positions of the joints of the beam and the frame column, enabling one end of a steel rope to penetrate through the holes to be wound at the positions of the joints of the beam and the frame column, fixing the steel rope by using bolts and a clamp, and lowering the other end of the steel rope onto the floor slab;

3) sequentially crushing and dismantling a wall, a floor slab, a secondary beam and an internal frame column in the storey height range of the storey to be exploded from top to bottom and from outside to inside;

4) Mechanically removing the outer wall in the storey height range of the storey to be exploded, and only reserving a section of outer wall which is not smaller than the explosion height of the outer frame column;

5) Mechanically cutting off transverse and longitudinal connection main beams connected with the outer frame columns within the storey height range of the storey to be exploded; drilling, charging and connecting with a detonating network;

6) The safety protection is carried out on the blasting part of the frame column by binding the straw curtain and the steel wire mesh;

7) A rope releasing hole is drilled in a floor slab at the joint position of the beam and the frame column, a pulley is installed and fixed at the position in a welding mode, and then a released steel rope is released to the lower layer through the rope releasing hole by bypassing the pulley;

8) hanging a heavy object at the tail end of the steel rope and firmly fixing the heavy object by using a bolt and a clamp, wherein the steel rope is stressed in a direction on a central axis of a joint of the beam and the frame column in the toppling direction; and (5) detonating.

2. The method for demolishing a building by blasting according to claim 1, wherein the blast height h of the frame column to be blasted of the building to be blasted is calculated by the formula:

The method comprises the following steps of calculating the explosion height of a frame column of a structure to be exploded by using an Euler formula, calculating the explosion height of the frame column by using h ₁, calculating the explosion height of the frame column of the structure to be exploded by using m, calculating the gravity of the structure to be exploded by using P, N, calculating N' by using the number of the frame columns of the structure to be exploded, calculating N by using the number of longitudinal ribs of a side column to be exploded, calculating E by using the elastic modulus of a steel bar, Pa, I by using the moment of inertia of the section of the steel bar, m ⁴, mu by using the length factor of the steel bar, calculating h ₂ by using an empirical formula, calculating the explosion height of the frame column.

3. the method for demolishing a building by blasting according to claim 1, wherein the minimum resistance line W, the pitch a and row b of blast holes, the hole depth l, and the packing length l ₁ are calculated according to the following equations:

W＝0.5B₁

a＝(1.0～1.3)W

b＝(0.6～0.9)a

l＝(0.6～0.65)B₁

l₁≥(1.1～1.2)W

Wherein W is the minimum resistant line m, a and B are the distance between blast holes and the row spacing m, l is the hole depth m, l ₁ is the blast hole filling length m, and B ₁ is the short side length m of the frame column to be exploded.

4. The method for demolishing a building by blasting according to claim 1, wherein the single-hole charging amount Q is calculated according to the following formula, and the charging structure is a single-hole double-shot uncoupled continuous charging structure;

Q＝qW²l

Wherein Q is the single-hole loading amount in kg, Q is the explosive consumption in kg/m ³, W is the minimum resistance line in m, and l is the hole depth in m.

5. The method for demolishing a building by blasting according to claim 1, wherein the blasting dumping direction is inward contraction and dumping toward the inside of the building, and the initiation sequence is opposite same-segment millisecond delay initiation; if there are several rows or columns of frame columns, the initiation sequence is from inside to outside, and the initiation is delayed by one row or column and same millisecond.

6. The method of demolishing a building by blasting according to claim 1, further comprising a safety check calculation of blasting according to the following formula:

R_F＝20K_Fn²W

wherein v is the vibration speed of a blasting mass point in cm/s, R is the distance from a blasting center to a key protection building, m, K' is a blasting field correction coefficient, K is a blasting field coefficient, alpha is a vibration wave attenuation coefficient, Q _max is the single-section maximum priming charge amount in kg, R _F is the safety distance of individual flyings, m, n is the blasting effect index of the maximum one charge, W is a minimum resistance line, m, K _F is a safety coefficient, R _C is the distance from the charging center to a target, m, and K _B is the safety coefficient.

7. The method for demolishing a building by blasting according to claim 1, further comprising checking the structural collapse touchdown impact destruction and the weight touchdown impact destruction by using the following formula:

F_max＝2πK₁mfv₀

the method is characterized in that v _t is mass point vibration speed cm/s caused by structural collapse and touchdown after demolition blasting, m is mass of a collapsed body, t, g is gravity acceleration m/s ², h _c is collapse weight center falling height m, sigma is destruction strength of a concrete member disassembled after building blasting, MPa, R' is distance between a protected building and an impact ground center, m, K _t and beta are attenuation coefficients and indexes of collapse vibration main vibration wave shape peak vibration speed, F _max is maximum impact load during touchdown collision, N, K ₁ is impact load reduction coefficient, K ₁ is recommended to be 0.1-0.25 when vibration reduction measures are adopted, K ₁ is recommended to be 0.5-1.0 when protective measures are not adopted, F is collapse body touchdown vibration main frequency, Hz, and v ₀ is initial velocity m/s when the collapsed body touchdown is adopted.

8. a method of demolishing a building by blasting according to claim 1, wherein the pre-tension value T applied to the structure to be blasted is:

Wherein T is a pre-tension value N applied to the structure to be exploded, N' is a safety coefficient larger than 1, and T _max is a maximum pre-tension value N capable of being born by the structure to be exploded;

the method is characterized in that T _max is the maximum pretension value which can be borne by a structure to be exploded, N, m is the self mass of the structure to be exploded, kg, g is the gravity acceleration, m/s ², A is the section area of a frame column, m ², e is the eccentricity of the structure to be exploded, m, I _z is the moment of inertia of the broken section of the frame column, m ⁴, l ₁ is the distance from a neutral axis to the edge of a tensioned region, m, e ₁ is the distance from a acting point of pretensioning force to the centroid of the frame column, m, h ₁ is the distance from the acting point of pretensioning force to the broken section of the frame column, m, theta is the included angle between the applied pretensioning force and the vertical direction, and [ sigma ] is the ultimate tensile strength and Pa of the section of the tensioned region of the frame column.

9. a method for demolishing a building by blasting according to claim 1, wherein the value of the pretension applied to the structure to be blasted is converted into the mass of the corresponding weight by a conversion formula:

Wherein M is the pretension value converted into the mass of the corresponding weight, kg, T is the pretension value applied to the structure to be exploded, N, g is the gravity acceleration, M/s ².

10. A method of demolishing a building by blasting according to claim 1, wherein the calculation formula of the suspension height of the weight is:

h_Suspension＝h

In the formula: h is_SuspensionM is the hanging height of the weight; h is the explosion height of the frame column of the structure to be exploded, m.

Technical Field

The invention belongs to the technical field of blasting demolition, and particularly relates to a blasting demolition method for a building.

Background

in recent years, as urban construction and transformation enter large-scale development stages, demolition works are more and more, and demolition blasting is widely applied to demolition works of buildings due to the outstanding advantages of safety, economy, high efficiency and the like. Demolition blasting is a general scheme for determining demolition blasting according to engineering requirements and surrounding environment characteristics by considering the structural characteristics of a building, and by means of fine measurement, careful design and fine construction and effective protection measures, the blasting action range of explosives, the collapse movement process of the building and the crushing degree of media are strictly controlled, the expected blasting effect is achieved, and meanwhile, the influence range and the hazard effect of blasting are controlled within allowable limits.

The buildings for controlling blasting demolition are generally positioned on a traffic main road, the peripheral buildings (structures) and key protection facilities have more equipment, complex pipelines, more people and vehicles, the engineering blasting timeliness is strong, and the safety requirement is high.

When the building is demolished by blasting, the traditional demolition blasting technologies such as directional blasting, folding blasting, in-situ collapse blasting and the like are generally adopted, but the demolition blasting technology provides a very serious challenge for the building demolition blasting technology for high-rise and super-high-rise buildings which have extremely complex surrounding environment, difficult site range to meet the dumping condition of the demolition blasting technology, strict control on blasting influence range and hazard effect and difficult mechanical demolition.

Therefore, it is urgently needed to provide a new fine blasting demolition method for buildings, i.e. inner-collapse layer blasting method, which is suitable for the above-mentioned complicated conditions.

disclosure of Invention

the invention aims at the problems and provides a blasting demolition method for an adduction landing building.

In order to achieve the purpose, the invention adopts the following technical scheme, and the invention comprises the following steps:

1) dismantling pipelines and auxiliary facilities inside a high-rise building to be exploded;

2) punching holes on a floor slab and a wall body at the positions of the joints of the beam and the frame column, enabling one end of a steel rope to penetrate through the holes to be wound at the positions of the joints of the beam and the frame column, fixing the steel rope by using bolts and a clamp, and lowering the other end of the steel rope onto the floor slab;

3) sequentially crushing and dismantling a wall, a floor slab, a secondary beam and an internal frame column in the storey height range of the storey to be exploded from top to bottom and from outside to inside;

4) Mechanically removing the outer wall in the storey height range of the storey to be exploded, and only reserving a section of outer wall which is not smaller than the explosion height of the outer frame column;

5) mechanically cutting off transverse and longitudinal connection main beams connected with the outer frame columns within the storey height range of the storey to be exploded; drilling, charging and connecting with a detonating network;

6) the safety protection is carried out on the blasting part of the frame column by binding the straw curtain and the steel wire mesh;

7) a rope releasing hole is drilled in a floor slab at the joint position of the beam and the frame column, a pulley is installed and fixed at the position in a welding mode, and then a released steel rope is released to the lower layer through the rope releasing hole by bypassing the pulley;

8) Hanging a heavy object at the tail end of the steel rope and firmly fixing the heavy object by using a bolt and a clamp, wherein the steel rope is stressed in a direction on a central axis of a joint of the beam and the frame column in the toppling direction; and (5) detonating.

As a preferred scheme, the method also comprises the step 9) of constructing a protective bent frame around the unexploded floor, and hanging a grass curtain at the periphery within the range of the floor height of the to-be-exploded floor for shielding, so that an overlapping part exists between the grass curtain and the bent frame.

as another preferred scheme, the method also comprises the step 10) of sprinkling water on the ground in the construction and blasting area.

as another preferable scheme, the invention further comprises the step 11) of placing a buffer medium right below the mounted heavy object.

As another preferable scheme, the formula for calculating the explosion height h of the frame column to be exploded of the building to be exploded in the invention is as follows:

the method comprises the following steps of calculating the explosion height of a frame column of a structure to be exploded by using an Euler formula, calculating the explosion height of the frame column by using h ₁, calculating the explosion height of the frame column of the structure to be exploded by using m, calculating the gravity of the structure to be exploded by using P, N, calculating N' by using the number of the frame columns of the structure to be exploded, calculating N by using the number of longitudinal ribs of a side column to be exploded, calculating E by using the elastic modulus of a steel bar, Pa, I by using the moment of inertia of the section of the steel bar, m ⁴, mu by using the length factor of the steel bar, calculating h ₂ by using an empirical formula, calculating the explosion height of the frame column.

As another preferred scheme, in the step 4), a section of outer wall not smaller than the explosion height of the outer frame column is reserved, and meanwhile, shielding protection is carried out on a protected building or facility with a short peripheral distance by building a protection bent and hanging a high-strength steel wire mesh, a wood board and a straw curtain.

as another preferred scheme, the method also comprises a structural overturning calculation mode, wherein the structural overturning calculation mode is that the overturning moment M _g of the structure after the blasting notch is formed is larger than the resisting bending moment M _z of the structure.

As another preferred scheme, the diameter of the blast hole is phi 42mm, the explosive is # 2 rock emulsion explosive, and the diameter of the cartridge is phi 32 mm.

As another preferred scheme, the minimum resistance line W, the distance a and the row pitch b of the blast holes, the hole depth l and the tamping length l ₁ are calculated according to the following formula:

W＝0.5B₁

a＝(1.0～1.3)W

b＝(0.6～0.9)a

l＝(0.6～0.65)B₁

l₁≥(1.1～1.2)W

wherein W is the minimum resistant line m, a and B are the distance between blast holes and the row spacing m, l is the hole depth m, l ₁ is the blast hole filling length m, and B ₁ is the short side length m of the frame column to be exploded.

as another preferred scheme, the specific consumption q of the explosive is determined by a method of comparing the calculated amount of the explosive of a single explosive package with the total explosive consumption.

As another preferred scheme, the blast holes are vertical blast holes, and the blast holes are arranged in a triangular or quincunx staggered arrangement.

as another preferred scheme, the single-hole loading Q is calculated according to the following formula, and the loading structure adopts a single-hole double-shot non-coupled continuous loading structure;

Q＝qW²l

wherein Q is the single-hole loading amount in kg, Q is the explosive consumption in kg/m ³, W is the minimum resistance line in m, and l is the hole depth in m.

As another preferred scheme, the blasting dumping direction is inward shrinkage dumping towards the inner side of the building, and the initiation sequence is opposite same-segment millisecond time delay initiation; if there are several rows or columns of frame columns, the initiation sequence is from inside to outside, and the initiation is delayed by one row or column and same millisecond.

As another preferred scheme, the initiation network of the invention adopts a non-electric-conductive detonator compound closed network, and the blast holes are connected with the detonating cross-joint after being connected with the detonator cluster for primary initiation on the same network.

As another preferable scheme, the invention also comprises a blasting safety checking calculation, which is calculated according to the following formula:

R_F＝20K_Fn²W

Wherein v is the vibration speed of a blasting mass point in cm/s, R is the distance from a blasting center to a key protection building, m, K' is a blasting field correction coefficient, K is a blasting field coefficient, alpha is a vibration wave attenuation coefficient, Q _max is the single-section maximum priming charge amount in kg, R _F is the safety distance of individual flyings, m, n is the blasting effect index of the maximum one charge, W is a minimum resistance line, m, K _F is a safety coefficient, R _C is the distance from the charging center to a target, m, and K _B is the safety coefficient.

In another preferred embodiment of the present invention, K' is 0.25 to 1.0, K is 30 to 500, α is 1.5 to 2.0, and K _F is 1.0 to 1.5.

as another preferable scheme, the invention also comprises the checking calculation of the structural collapse touchdown impact damage and the weight touchdown impact damage, and the checking calculation formula is as follows:

F_max＝2πK₁mfv₀

The method is characterized in that v _t is mass point vibration speed cm/s caused by structural collapse and touchdown after demolition blasting, m is mass of a collapsed body, t, g is gravity acceleration m/s ², h _c is collapse weight center falling height m, sigma is destruction strength of a concrete member disassembled after building blasting, MPa, R' is distance between a protected building and an impact ground center, m, K _t and beta are attenuation coefficients and indexes of collapse vibration main vibration wave shape peak vibration speed, F _max is maximum impact load during touchdown collision, N, K ₁ is impact load reduction coefficient, K ₁ is recommended to be 0.1-0.25 when vibration reduction measures are adopted, K ₁ is recommended to be 0.5-1.0 when protective measures are not adopted, F is collapse body touchdown vibration main frequency, Hz, and v ₀ is initial velocity m/s when the collapsed body touchdown is adopted.

as another preferred scheme, the pre-tension value T applied to the structure to be exploded in the invention is as follows:

Wherein T is a pre-tension value N applied to the structure to be exploded, N' is a safety coefficient larger than 1, and T _max is a maximum pre-tension value N capable of being born by the structure to be exploded;

The method is characterized in that T _max is the maximum pretension value which can be borne by a structure to be exploded, N, m is the self mass of the structure to be exploded, kg, g is the gravity acceleration, m/s ², A is the section area of a frame column, m ², e is the eccentricity of the structure to be exploded, m, I _z is the moment of inertia of the broken section of the frame column, m ⁴, l ₁ is the distance from a neutral axis to the edge of a tensioned region, m, e ₁ is the distance from a acting point of pretensioning force to the centroid of the frame column, m, h ₁ is the distance from the acting point of pretensioning force to the broken section of the frame column, m, theta is the included angle between the applied pretensioning force and the vertical direction, and [ sigma ] is the ultimate tensile strength and Pa of the section of the tensioned region of the frame column.

As another preferable scheme, the conversion formula of the pretension force value applied to the structure to be exploded in the invention converted into the mass of the corresponding weight is as follows:

Wherein M is the pretension value converted into the mass of the corresponding weight, kg, T is the pretension value applied to the structure to be exploded, N, g is the gravity acceleration, M/s ².

As another preferable scheme, the calculation formula of the weight suspension height of the present invention is:

h_Suspension＝h

In the formula: h is_suspensionm is the hanging height of the weight; h is a structural frame to be explodedThe explosion height of the frame column is m.

As another preferable scheme, the included angle between the pretensioning force and the vertical direction is controlled within the range of 45-60 degrees.

secondly, when the outer wall is dismantled in the step 4), horizontal safety protection greenhouses with the cantilever length of 6m are erected every four layers, horizontal protective nets are arranged every two layers, and extension structures for preventing high-altitude objects from falling are additionally arranged around the bottom layer of a high-rise building.

In addition, the invention also comprises the checking calculation of the structural stability after the pretreatment before blasting and the checking calculation of the structural stability after beam breaking, and the checking calculation formula is as follows:

in the formula, F _cr is the critical instability load that the steel bar in the frame column to be exploded can bear, N ', N' is the number of longitudinal bars in the frame column to be exploded, E is the elastic modulus of the steel bar, MPa, I is the moment of inertia of the section of the steel bar, m ⁴, mu is the length factor, and h is the explosion height of the frame column, m.

the invention has the beneficial effects.

the invention can ensure that the blasting influence range is small and the damage effect is small by implementing the steps 1) to 8), and is suitable for blasting demolition of high-rise buildings.

Drawings

the invention is further described with reference to the following figures and detailed description. The scope of the invention is not limited to the following expressions.

Fig. 1 and 2 show a building [ a reinforced concrete frame shear wall structure, 28 floors above ground + 2 floors below ground, 35.8m in length from north to south, 32.8m in east-west width and 99.995m in building height. 5 rows of upright columns (south-north direction) and 5 columns of upright columns (east-west direction) are arranged, the middle parts, the stairs and the elevator shaft are shear wall structures, the upright columns and the shear walls are C40, C50 or C60 common cast-in-place concrete, and the steel bars are I-grade and II-grade respectively. The 39m position of the northeast is a villa area; a subway is arranged at the position of 50m on the south-east side, and a worker rest room is arranged at the position of 54 m; the south side 39m is a road; the 41m position of the southwest side is a street; company at 79m north; the northwest side 72 is an on-site transformer, the ticket office at 78m, and the hospital at 91 m. The number of buildings (structures) and facilities to be protected is large, the collapse space is limited, the blasting requirement is high, and the dismantling difficulty is large. The interior of the building is of an approximate square structure, the rigidity is good, the building is difficult to tear in the blasting process, the building to be demolished needs to be fully pretreated before blasting construction, the overall quality and the volume of concrete of the building to be demolished are very large, the impact strength on the ground after blasting collapse by adopting the traditional blasting demolition technology is large, splashes after the ground is extremely difficult to control, secondary disasters are easy to cause, the protection difficulty and the technical requirement are high, and the quality requirement of a protection material is high, and the floor plan and the plan of 13-28 layers are provided;

FIG. 3 is a schematic diagram of the blasting of the inner descending layer;

FIG. 4 is a schematic diagram of a single inner descending layer blasting layer height range;

FIG. 5 is a schematic of a steel cable and pulley arrangement;

FIG. 6 is a schematic view of a blast hole arrangement;

FIG. 7 is a schematic view of a charge configuration;

FIG. 8 is a schematic illustration of the initiation sequence and collapse direction;

FIG. 9 is a schematic view of a detonating circuit;

FIG. 10 is a schematic representation after pretreatment;

Fig. 11 is a schematic diagram of the safety protection of blasting.

in the figure, 1 — frame post; 2-transverse connection main beam; 3, longitudinally connecting the main beam; 4, a window; 5, building a block wall; 6, a floor slab; 7-shear wall; 8, an elevator shaft; 9, stairs; 10, a part to be blasted of the frame column; 11-steel cord; 12-a pulley; 13-rope placing hole; 14-a mounted weight; 15-blast hole; 16-a detonating tube; 17-stuffing; 18-uncoupled continuous charge structure; 19-air; 20-delay detonator in hole; 21-explosive cartridge; 22-surface delay detonator; 23-four-way; 24-a detonation station; 25-steel wire mesh; 26-straw curtain.

Detailed Description

As shown, the present invention comprises the following steps, see fig. 10:

1) Dismantling pipelines and auxiliary facilities inside a high-rise building to be exploded;

2) Punching holes on a floor slab and a wall body at the positions of the joints of the beam and the frame column, enabling one end of a steel rope to penetrate through the holes to be wound at the positions of the joints of the beam and the frame column, fixing the steel rope by using bolts and a clamp, and lowering the other end of the steel rope onto the floor slab;

3) Sequentially crushing and dismantling a wall, a floor slab, a secondary beam and an internal frame column in the storey height range of the storey to be exploded from top to bottom and from outside to inside;

4) Mechanically removing the outer wall in the storey height range of the storey to be exploded, and only reserving a section of outer wall which is not smaller than the explosion height of the outer frame column;

5) mechanically cutting off transverse and longitudinal connection main beams connected with the outer frame columns within the storey height range of the storey to be exploded;

6) The blasting part of the frame column is safely protected by binding the straw curtain and the steel wire mesh, as shown in figure 11;

7) A rope releasing hole is drilled in a floor slab at the joint position of the beam and the frame column, a pulley is installed and fixed at the position in a welding mode, and then a released steel rope is released to the lower layer through the rope releasing hole by bypassing the pulley;

8) Hanging a heavy object at the tail end of the steel rope and firmly fixing the heavy object by using a bolt and a clamp, wherein the steel rope is stressed in a direction on a central axis of a joint of the beam and the frame column in the toppling direction; and (5) detonating.

And step 9) constructing a protective bent frame around the unexploded floor, and hanging a grass curtain at the periphery of the floor to be exploded within the floor height range for shielding, so that an overlapped part exists between the grass curtain and the bent frame, and the explosive is prevented from flying out.

And the method also comprises the step 10) of sprinkling water on the ground of the construction and blasting area, increasing the humidity of the ground and reducing the dust amount.

And the method also comprises the step 11) of placing a buffer medium right below the mounted heavy object. The buffer medium can adopt tires, and the impact damage to the floor slab when the structure to be exploded is adducted, toppled and contacted with the ground is reduced.

and 8) enabling the stress direction of the steel rope to be on a central axis of the joint center position of the beam and the frame column in the toppling direction (see fig. 5).

The calculation formula of the explosion height h (see fig. 6) of the frame column to be exploded of the building to be exploded at the high-rise building is as follows:

the method is characterized in that h is the explosion height of a frame column of a structure to be exploded, m, h ₁ is the explosion height of the frame column calculated according to an Euler formula, P is the gravity of the structure to be exploded, N, N' is the number of the frame columns of the structure to be exploded, N is the number of longitudinal ribs of a side column to be exploded, E is the elastic modulus of a steel bar, Pa, I is the moment of inertia of the section of the steel bar, m ⁴, mu is the length factor of the steel bar, h ₂ is the explosion height of the frame column, m, and B is the length of a long side of the frame column to be exploded, m.

and 4) reserving a section of outer wall not smaller than the explosion height of the outer frame column, and shielding and protecting the protected buildings or facilities with the peripheral distance of 50m by building a protective bent and hanging a high-strength steel wire mesh, a wood board and a straw curtain.

and structural overturning checking calculation is carried out in a mode that the overturning moment M _g of the structure after the blasting notch is formed is larger than the resisting bending moment M _z of the structure.

The diameter of a blast hole is phi 42mm, the explosive is 2# rock emulsion explosive, and the diameter of a cartridge is phi 32 mm.

The minimum resistance line W, the hole pitch a and the row pitch b, the hole depth l, and the stemming length l ₁ were calculated by the following equations (see fig. 7):

W＝0.5B₁

a＝(1.0～1.3)W

b＝(0.6～0.9)a

l＝(0.6～0.65)B₁

l₁≥(1.1～1.2)W

Wherein W is the minimum resistant line m, a and B are the distance between blast holes and the row spacing m, l is the hole depth m, l ₁ is the blast hole filling length m, and B ₁ is the short side length m of the frame column to be exploded.

And the unit explosive consumption q is determined by a method of comparing the calculated explosive amount of a single explosive package with the total explosive consumption.

the blast holes are vertical blast holes and are arranged in a triangular or quincunx staggered arrangement (see figure 6).

the single-hole loading Q is calculated according to the following formula, and the loading structure (shown in figure 7) adopts a single-hole double-shot uncoupled continuous loading structure;

Q＝qW²l

wherein Q is the single-hole loading amount in kg, Q is the explosive consumption in kg/m ³, W is the minimum resistance line in m, and l is the hole depth in m.

The blasting dumping direction is to retract and dump towards the inner side of the building, and the initiation sequence is opposite to the same-segment millisecond time delay initiation; if there are more rows or columns of frame columns, the initiation sequence is from inside to outside, and the initiation is delayed by one row or column by one millisecond, as shown in fig. 8.

The detonating network adopts a non-electric detonator compound closed network (the non-electric detonator in the hole is used as a detonating element, the detonating detonator stranded wires in the blast holes of the same row are connected by two detonating tubes hole by hole and transversely by four-way connection, the periphery between the rows is closed by the detonating tubes to form a single compound non-electric detonator closed network detonating system), the blast holes are connected by detonator clusters and then connected with the detonating four-way connection on the same network for primary detonating, as shown in figure 9.

the method also comprises blasting safety checking calculation according to the following formula:

R_F＝20K_Fn²W

wherein v is the vibration speed of a blasting mass point in cm/s, R is the distance from a blasting center to a key protection building, m, K' is a blasting field correction coefficient, K is a blasting field coefficient, alpha is a vibration wave attenuation coefficient, Q _max is the single-section maximum priming charge amount in kg, R _F is the safety distance of individual flyings, m, n is the blasting effect index of the maximum one charge, W is a minimum resistance line, m, K _F is a safety coefficient, R _C is the distance from the charging center to a target, m, and K _B is the safety coefficient.

the K' is 0.25-1.0, K is 30-500, alpha is 1.5-2.0, and K _F is 1.0-1.5.

The method also comprises the checking calculation of the structural collapse touchdown impact damage and the heavy object touchdown impact damage, wherein the checking calculation formula is as follows:

F_max＝2πK₁mfv₀

The method is characterized in that v _t is mass point vibration speed cm/s caused by structural collapse and touchdown after demolition blasting, m is mass of a collapsed body, t, g is gravity acceleration m/s ², h _c is collapse weight center falling height m, sigma is destruction strength of a concrete member disassembled after building blasting, MPa, R' is distance between a protected building and an impact ground center, m, K _t and beta are attenuation coefficients and indexes of collapse vibration main vibration wave shape peak vibration speed, F _max is maximum impact load during touchdown collision, N, K ₁ is impact load reduction coefficient, K ₁ is recommended to be 0.1-0.25 when vibration reduction measures are adopted, K ₁ is recommended to be 0.5-1.0 when protective measures are not adopted, F is collapse body touchdown vibration main frequency, Hz, and v ₀ is initial velocity m/s when the collapsed body touchdown is adopted.

The pre-tension value T applied to the structure to be exploded is:

wherein T is a pre-tension value applied to the structure to be exploded, N, N' is a safety coefficient larger than 1, T _max is a maximum pre-tension value which can be borne by the structure to be exploded, N:

The method is characterized in that T _max is the maximum pretension value which can be borne by a structure to be exploded, N, m is the self mass of the structure to be exploded, kg, g is the gravity acceleration, m/s ², A is the section area of a frame column, m ², e is the eccentricity of the structure to be exploded, m, I _z is the moment of inertia of the broken section of the frame column, m ⁴, l ₁ is the distance from a neutral axis to the edge of a tensioned region, m, e ₁ is the distance from a acting point of pretensioning force to the centroid of the frame column, m, h ₁ is the distance from the acting point of pretensioning force to the broken section of the frame column, m, theta is the included angle between the applied pretensioning force and the vertical direction, and [ sigma ] is the ultimate tensile strength and Pa of the section of the tensioned region of the frame column.

the conversion formula for converting the pretension force value applied to the structure to be exploded into the mass of the corresponding weight is as follows:

Wherein M is the pretension value converted into the mass of the corresponding weight, kg, T is the pretension value applied to the structure to be exploded, N, g is the gravity acceleration, M/s ².

The formula for calculating the suspension height of the weight is as follows:

h_Suspension＝h

In the formula: h is_SuspensionM is the hanging height of the weight; h is the explosion height of the frame column of the structure to be exploded, m.

And the included angle between the pretensioning force and the vertical direction is controlled within the range of 45-60 degrees.

and 4) when the outer wall is dismantled, horizontal safety protection greenhouses with the overhanging length of 6m are erected every four layers, horizontal protective nets are arranged every two layers, and extension structures for preventing high-altitude objects from falling are additionally arranged around the bottom layer of a high-rise building.

The method also comprises the checking calculation of the structural stability after the pretreatment before blasting and the checking calculation of the structural stability after beam breaking, wherein the checking calculation formula is as follows:

In the formula, F _cr is the critical instability load that the steel bar in the frame column to be exploded can bear, N ', N' is the number of longitudinal bars in the frame column to be exploded, E is the elastic modulus of the steel bar, MPa, I is the moment of inertia of the section of the steel bar, m ⁴, mu is the length factor, and h is the explosion height of the frame column, m.

The invention applies continuous pretension force (pretension force applied by a heavy object hung at the tail end of the steel rope) to the dumping direction, and places buffer media such as tires and the like (namely buffer media placed under the hung heavy object) in the collapsing range so as to ensure that the structure to be exploded can be safely and accurately retracted and dumped in a building boundary.

The method is suitable for demolishing high-rise or super high-rise buildings with the length-width ratio approximately equal to 1, particularly high-rise or super high-rise buildings with complicated surrounding environments and difficult demolishing by the traditional blasting demolishing technology (such as directional blasting, folding blasting, in-situ collapse blasting and the like).

it should be understood that the detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can be modified or substituted equally to achieve the same technical effects; as long as the use requirements are met, the method is within the protection scope of the invention.