Construction method and control system for protective dismantling of factory building

Abstract

The invention discloses a construction method and a control system for protective dismantling of a plant. The construction method comprises the following steps: S1, dismantling a roof and a wall body; s2, the reinforced concrete columns which do not need to retain the column body structure are destructively dismantled, and the destructive dismantling of the reinforced concrete columns adopts an excavator to mechanically and destructively dismantle the reinforced concrete columns one by one; s3, the reinforced concrete column needing to retain the complete structure of the column body of the reinforced concrete column is dismantled in a protective mode, before the reinforced concrete column is dismantled in a protective mode, the root of the bracket of the I-shaped column is bound through a steel wire rope, binding is firm, and then hoisting equipment is used for slow hoisting; and then 1: 0.5 sloping excavation is conducted within a certain range of the column foot of the concrete column, part of the column foot is exposed, topsoil is manually cleaned, and then static cutting is conducted on the concrete column through a rope saw cutting machine. The overall safety and stability problem of an original building in the demolition operation process or the new building process after demolition is solved, and the overturning risk is eliminated under the condition that the original structure is protected against damage.

Description

Technical Field

[0001] The present invention relates to the field of building construction. More specifically, the present invention relates to a construction method and control system for the protective demolition of a factory building. Background Art

[0002] With the acceleration of the urban renewal process, the protective renovation projects of industrial heritage buildings are increasing day by day. The renovation of industrial factory buildings with historical value faces special challenges: it is necessary to completely retain specific structural members for the decorative reconstruction of new buildings, and at the same time, it is necessary to efficiently demolish the non-retained parts. The traditional demolition methods for reinforced concrete structures have significant limitations, especially in the field of protective demolition, the following problems are exposed: 1) The mechanical crushing method uses a hydraulic breaker to directly impact the structure. Although the efficiency is relatively high, it will generate strong vibrations (the measured vibration speed can reach 30 mm / s), which is extremely likely to cause hidden damage to the double-column and adjacent structures in the reserved area. In this project, the connection accuracy requirement of the 18 decorative columns to be retained in situ with the new structure is ±5 mm, and the traditional method is difficult to meet. 2) Although the blasting demolition can quickly disassemble the structure, the air shock wave (peak overpressure > 0.1 MPa) and flying debris generated by it pose a safety threat to the existing buildings within 50 m. The project site is adjacent to the main road (the closest distance is 9.6 m), and it is completely not suitable for implementation. 3) Due to the defects of the existing static cutting technology, such as open-loop control of the cutting depth, empirical hoisting intervention, insufficient monitoring accuracy, and discrete equipment coordination, there are uncontrollable instability risks and efficiency losses during the demolition process. Summary of the Invention

[0003] The purpose of the present invention is to provide a construction method and control system for the protective demolition of a factory building, to solve the overall safety and stability problems of the original building during the demolition operation or the new construction process after demolition, and to eliminate the overturning risk while protecting the original structure from being damaged.

[0004] The technical solution adopted by the present invention to solve this technical problem is: a construction method for the protective demolition of a factory building, including the following steps: S1. Demolish the roof and walls; S2. For the reinforced concrete columns that do not need to retain the column structure, adopt destructive demolition. The destructive demolition of the reinforced concrete columns is carried out one by one by an excavator for mechanical destructive demolition; S3. For the reinforced concrete columns that need to retain the complete structure of the column body, adopt protective demolition. Before the protective demolition of the reinforced concrete columns, bind the root of the I-shaped column corbel with steel wire ropes and tie them firmly, and then slowly lift it with a hoisting device; then, carry out a 1:0.5 slope excavation within a certain range of the column foot of the concrete column to expose part of the column foot, and manually clean the floating soil, and then use a wire saw cutting machine to carry out static cutting on the concrete column.

[0005] As a further solution of the present invention: Specifically included in S1 is as follows: S11. Protection and reinforcement construction: Erect a steel pipe scaffold for protection. First, reinforce the structural columns to be retained. Specifically: Add column bracings between the first-span structural column and the last-span structural column. All the original column bracings are retained. Horizontally connect tie rods between each span of structural columns. Then, fix the upper part of the column feet of the column bracings and the lower part of the corbels to the structural columns in the form of hoop fasteners. S12. Demolition operation: S12a. Roof demolition: Separate the precast slabs and ring beams one by one, lift the slabs with a crane, and lower them to the ground for recycling or crushing. S12b. Wall demolition: Demolish the wall from top to bottom, with the height of each demolition not exceeding 1000 mm. Transfer the demolished brick debris to the designated place on the site with an excavator for paving the temporary access road on the site. S12c. Steel roof truss demolition: Follow the principle of from top to bottom, non-load-bearing first and then load-bearing. First, pre-tension the steel truss upward with a crane, release the connection points of the steel truss one by one, and then gently lower it to the ground.

[0006] As a further solution of the present invention: The specific implementation of the column bracings between the first span and the last span and the connection of the column tie rods in S11 includes: vertical poles, longitudinal horizontal bars, transverse horizontal bars, column clamps, and inverted V-shaped diagonal braces; The vertical poles, longitudinal horizontal bars, and transverse horizontal bars form the scaffold body. The scaffold body is connected to the original concrete structural column through column clamps, and the inverted V-shaped diagonal braces are fixed to the corresponding original concrete structural columns on both sides.

[0007] As a further solution of the present invention: The static cutting of the concrete column using a wire saw in S3 specifically includes the following steps: S31. Install pressure sensors and displacement sensors in the predetermined cutting area of the reinforced concrete column to collect the axial pressure value F and the column body offset ΔL during the cutting process in real time. S32. Obtain the cutting wire speed v in real time through the wire speed sensor of the wire saw cutting machine, and record the effective cutting time t by a timer. S33. Input the wire speed v, cutting time t, and axial pressure value F into the central control unit. According to the pre-stored material strength coefficient k and cutting efficiency coefficient η, calculate the real-time cutting depth h according to the formula h = η·v·t·(F / k) 0.5 Calculate the real-time cutting depth h; S34. When the calculated cutting depth h reaches 80 - 90% of the critical cutting depth H g Apply prestress to 0.2 - 0.3 times the self-weight of the column body by controlling the lifting tackle of the hoisting equipment, and synchronously adjust the feed rate of the wire saw cutting machine to 50 - 60% of the initial rate; S35. Continuously monitor the column body offset ΔL. When ΔL ≥ 0.15Hg When this occurs, immediately stop cutting and start the synchronous lifting procedure of the hoisting equipment until the cutting section is completely separated and then implement directional transfer.

[0008] As a further solution of the present invention: The pressure sensors are symmetrically arranged on both side surfaces of the reinforced concrete column along the axial direction of the column, 20 - 30 cm above the predetermined cutting line.

[0009] As a further solution of the present invention: The displacement sensors include a horizontal displacement sensor and a vertical displacement sensor; The horizontal displacement sensor is installed on the side surface of the reinforced concrete column body 10 - 15 cm above the cutting line to monitor the lateral offset; The vertical displacement sensor is installed at the center point of the column top to monitor the vertical settlement.

[0010] As a further solution of the present invention: The vertical displacement sensor is a laser emitter and a reflecting target. Among them, the laser emitter is installed adjacent to the stable structure, with a horizontal distance of 5 - 10 m from the column to be cut, and a reflecting target is installed on the column top of the column to be cut.

[0011] As a further solution of the present invention: The calculation method of the column body offset ΔL in S35 includes: The horizontal displacement sensor real - time collects the lateral offset ΔL at 10 - 15 cm above the cutting line h , and the vertical displacement sensor real - time collects the vertical settlement ΔL at the center point of the column top v ; Calculate the total offset effect during the column body toppling process: , where H is the total height of the reinforced concrete column, and H' is the height difference between the vertical displacement sensor and the cutting line.

[0012] The present invention also provides a control system for the construction method of the protective demolition of the factory building described above, including: A sensor module, which consists of at least two groups of axial pressure sensors and displacement sensors installed on both sides of the predetermined cutting area of the reinforced concrete column; A wire saw parameter acquisition module, which is a linear velocity sensor and a timer integrated on the drive motor of the wire saw cutting machine, used to obtain the cutting line speed v and the effective cutting time t in real - time; A data communication module, which transmits the data of the sensor module and the wire saw parameter acquisition module to the central control unit through wired / wireless transmission; A central control unit, in which a calculation module is set. The calculation module pre - stores the material strength coefficient k and the cutting efficiency coefficient η, and executes the real - time operation of the formula h = η·v·t·(F / k) 0.5 and outputs the cutting depth h and the critical state determination signal; The execution module includes a hoisting equipment controller and a wire saw feed rate regulator. After receiving the critical state determination signal, the hoisting equipment controller controls the hoisting tackle to apply a prestress of 0.2 - 0.3 times the self-weight of the column, and at the same time, the wire saw feed rate regulator reduces the cutting rate to 50 - 60% of the initial value; The safety redundancy module, when the displacement sensor detects that ΔL ≥ 0.15H g triggers an emergency stop command to cut off the power supply of the wire saw and activate the hoisting synchronous lifting program.

[0013] The present invention has at least the following beneficial effects: 1. The safety of demolition is improved through the scaffold and structural reinforcement. Diagonal braces and horizontal tie rods in a shape of an eight are added at the first and last spans, the lateral stiffness of the cantilever column is increased, and the displacement during the demolition process is ≤ 2 mm.

[0014] 2. After the protective demolition, a high reuse rate of components is achieved. Through the coordinated control of wire saw static cutting and hoisting, the reinforced concrete column is completely retained and used for the decorative components of the new building. The flatness error of the cutting surface is ≤ 3 mm (the traditional method > 10 mm), meeting the accuracy requirements of decorative installation. The reuse of components reduces construction waste and carbon emissions.

[0015] 3. Based on the formula designed in this application, the dynamic cutting depth is combined with the suppression of instability risk, and the error is compressed from ±15% of the traditional empirical method to ±5%. The critical depth threshold triggers the hoisting prestress (0.2 - 0.3 times the self-weight) and the wire saw speed reduction (50 - 60%), forming a dual redundancy protection mechanism.

[0016] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Brief Description of the Drawings

[0017] Figure 1 is the schematic diagram of the crane station position for demolishing the reinforced concrete column of the present invention; Figure 2 is the elevation view of the structural column reinforcement of the present invention; Figure 3 is the schematic diagram of the connection of the column bracing and the column tie rod between the first and last spans of the present invention; Figure 4 is the schematic diagram of the control system of the present invention.

[0018] Among them, 1 - crane, 2 - I-shaped column, 3 - additional column bracing, 4 - original column bracing, 5 - horizontal connecting tie rod, 6 - vertical pole, 7 - longitudinal horizontal bar, 8 - transverse horizontal bar, 9 - column holding, 10 - diagonal brace in a shape of an eight. Detailed Embodiment

[0019] The present invention will be described in detail and completely below in conjunction with the accompanying drawings. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that: the technical solutions and technical features provided in each part including the following description of the present invention can be combined with each other without conflict.

[0020] In addition, the embodiments of the present invention involved in the following description are usually only some embodiments of the present invention, rather than all embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention.

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, and the specific implementation process is as follows: The core purpose of the protective demolition of reinforced concrete columns is to retain the unique style of historical buildings. Historical buildings in different regions often have their own characteristics, and their concrete columns carry the local regional cultural imprints. When these concrete columns are subjected to protective demolition and the corresponding buildings are renovated, the concrete columns that are completely retained will become decorative columns (without the function of load-bearing structures) and will be installed in the renovated factory buildings. In this way, the new factory building can still retain the extremely historical unique style contained in the local buildings.

[0022] When carrying out the protective demolition work on reinforced concrete columns, there is no established and clear demolition quantity standard. Exactly how many to demolish specifically often needs to be comprehensively determined according to the design scheme and actual needs of each building. After determining the quantity of the protective demolition of reinforced concrete columns for each project (this quantity should be slightly more than the actual designed number of decorative columns as an alternative), the remaining reinforced concrete columns can be demolished destructively.

[0023] This demolition project includes three factory buildings: Workshop 1, Workshop 2, and Steel Plate Warehouse. The main structure of the factory buildings to be demolished is a reinforced concrete double-column + steel roof truss structure, with a designed service life of 50 years, a seismic fortification category of Class B, a building structure safety grade of Grade II (including the foundation), a seismic intensity of 6 degrees, and a frame seismic grade of Grade IV.

[0024] The present invention provides a construction method for the protective demolition of factory buildings, including the following steps: S1. Demolish the roof and walls; S2. For the reinforced concrete columns whose column structures do not need to be retained, carry out destructive demolition. The destructive demolition of the reinforced concrete columns is carried out by an excavator one by one for mechanical destructive demolition; S3. For the reinforced concrete columns that need to retain the complete structure of the column body, protective demolition is adopted. Before the protective demolition of the reinforced concrete column, the root of the I-shaped column corbel is bound with steel wire ropes and tied firmly. As shown in Figure 1 , then it is slowly lifted by a hoisting device; then, within a certain range (3.3 m in this embodiment) of the column foot of the concrete column, slope excavation is carried out at a ratio of 1:0.5 to expose part of the column foot, and the floating soil is manually cleaned. Then, a wire saw cutting machine is used to perform static cutting on the concrete column to ensure the integrity of the component.

[0025] Specifically, as shown in Figure 2 , specifically included in S1 are: S11. Protection and reinforcement construction, adopting the erection of a steel pipe scaffold for protection. Specifically: The site is leveled, and the ground debris around the building to be demolished is cleared. The ground of the scaffold foundation is the original cement hardened ground, and the concrete thickness is about 200 mm. The damaged parts of the original concrete ground are repaired by hardening with C20 concrete to meet the requirements for scaffold erection.

[0026] According to the requirements of the frame design dimensions, the positions of the inner and outer rows of vertical poles are determined. The distance between the inner vertical pole of the frame and the outer wall is 300 mm, and the distance between the inner and outer rows of vertical poles of the scaffold is 900 mm. A full-length base plate should be set at the bottom of each vertical pole, and longitudinal and transverse ground-sweeping bars must be set. The longitudinal ground-sweeping bar should be fixed to the vertical pole not more than 200 mm above the upper surface of the base by a right-angle fastener. The transverse ground-sweeping bar should also be fixed to the vertical pole immediately below the longitudinal ground-sweeping bar by a right-angle fastener. The longitudinal horizontal bar should be preferably set inside the vertical pole, and its length should not be less than three spans. The step distance of the longitudinal horizontal bar is 1800 mm; an additional handrail horizontal bar is erected between the two outer horizontal bars, and the distance between the longitudinal horizontal bars is 900 mm; two additional longitudinal horizontal bars are added between the longitudinal horizontal bars for erecting the hard protection layer and evenly arranged. The transverse horizontal bar (small cross bar) is installed above the longitudinal horizontal bar, and the distance between the transverse horizontal bars at the operation layer is 750 mm, and the distance between the transverse horizontal bars at the non-operation layer is 1500 mm. The scaffold and the building are rigidly connected by steel pipe connecting members, that is, the scaffold and the structural columns in the original building are reliably connected together by using steel pipes, fasteners, etc. The setting spacing of the connecting members: the horizontal spacing is 6000 mm; the vertical spacing is 5400 mm. The connecting members are all connected to the load-bearing columns by means of hugging the columns. According to the height of the scaffold, the scaffold boards are fully paved on the first layer, every 5 steps and the operation layer; the scaffold boards should be paved stably, leaving 120 - 150 mm away from the wall, and toe boards are set at the operation layer and the periphery of the platform. The height of the scaffold in this project is basically below 24 m. On the outer side ends, corners and the elevations at intervals not exceeding 15 m in the middle, a diagonal brace is set for each, and it is continuously set from the bottom to the top and painted with red and white paint. The outer side elevation of the scaffold is fully enclosed with a dense mesh, and the dense mesh should be set inside the outer row of vertical poles.

[0027] Considering that after the workshop roof structure is removed, the structural columns are in an independent cantilever state, in order to ensure safety and stability during the removal process and when they are retained in situ after removal, the structural columns to be retained are first reinforced to prevent the structural columns from becoming unstable and collapsing during the removal of the roof and walls. Specifically, inter-column supports 3 are added to the first span structural columns and the last span structural columns, and all the original inter-column supports 4 are retained. Tie rods 5 are horizontally connected between the structural columns of each span, and then the upper part of the column foot and the lower part of the corbel of the inter-column support are fixed to the structural column in the form of a hoop; S12. Demolition work: S12a, roof dismantling: separate the prefabricated panels, ring beams, etc. piece by piece, lift the panels with a 100T crane 1, and lower them to the ground for recycling or crushing; S12b, wall demolition: the wall is demolished from top to bottom, and the demolition height each time does not exceed 1000mm. The brick slag after demolition is transported by excavator to the designated place on site for storage and used for paving temporary access roads on site; S12c, Steel Roof Truss Dismantling: From top to bottom, first non-load-bearing and then load-bearing, use a 100T crane to pre-tension the steel frame upwards, release the steel frame connection points one by one, and then lower it steadily to the ground.

[0028] Specifically, Figure 3 As shown, the support between the columns of the first span and the last span and the connection of the tie rods between the columns in S11 specifically include: vertical poles 6, longitudinal horizontal poles 7, transverse horizontal poles 8, brackets 9 and figure-eight diagonal braces 10; the vertical poles, longitudinal horizontal poles and transverse horizontal poles are combined to form a scaffold body, which is connected to the original concrete structure columns through the brackets, and the figure-eight diagonal braces are tied and fixed to the original concrete structure columns on both sides corresponding to them to ensure the overall stability of the scaffold.

[0029] Specifically, the static cutting of the concrete column by using a wire saw in S3 specifically includes the following steps: S31, installing a pressure sensor and a displacement sensor in a predetermined cutting area of ​​a reinforced concrete column, and collecting the axial pressure value F and the column offset ΔL in real time during the cutting process; S32, obtaining the cutting line speed v in real time through the line speed sensor of the wire saw cutting machine, and recording the effective cutting time t by a timer; S33, the linear velocity v, cutting time t and axial pressure value F are input into the central control unit, and the pre-stored material strength coefficient k and cutting efficiency coefficient η are used according to the formula h=η·v·t·(F / k) 0.5 Calculate the real-time cutting depth h; The material strength coefficient k is the comprehensive strength coefficient of the reinforced concrete column to resist damage during the cutting process: k=0.85f c +0.15·p·f y , where fc is the axial compressive strength of concrete, and f y is the yield strength of steel bars, and p is the reinforcement ratio.

[0030] The cutting efficiency coefficient η is the effective cutting efficiency of the wire saw cutting machine for reinforced concrete columns per unit time. η = actual cutting capacity / theoretical cutting capacity. The actual cutting capacity can be obtained through cutting tests on the reinforced concrete columns demolished destructively on site.

[0031] S34. When the cutting depth h < 0.8 - 0.9H g and ΔL < 0.15H g , the column may have millimeter-level offsets due to the redistribution of loads (such as ΔL ≈ 0.05H), but dynamic stability can be maintained through prestress and rate adjustment. When the calculated cutting depth h reaches 80 - 90% of the critical cutting depth H g , the hoisting tackle of the hoisting equipment is controlled to apply prestress to 0.2 - 0.3 times the self-weight of the column, and the feed rate of the wire saw cutting machine is synchronously adjusted to 50 - 60% of the initial rate; among them, the critical cutting depth H g refers to the cutting depth threshold when the flexural bearing capacity of the remaining cross-section of the reinforced concrete column is insufficient to balance the external loads (self-weight, wind load) during the cutting process. During the construction of this project, the critical cutting depth H of the reinforced concrete column is uniformly calculated and g defined as 0.8m.

[0032] S35. Continuously monitor the column offset ΔL. When ΔL ≥ 0.15H g , immediately stop cutting and start the synchronous lifting program of the hoisting equipment to avoid accelerating tipping until the cutting section is completely separated and then implement directional transfer.

[0033] Taking the I-shaped concrete column to be demolished in this embodiment as an example, the column length is 16.55m. After preliminary estimation, the weight of a single I-shaped column 2 is about 27t. A Zoomlion ZTC100T truck crane is used, equipped with a 6·37-φ32.5mm steel wire rope (indicating that the steel wire rope is made of 6 strands; there is a fiber rope core in the middle of each strand and 37 steel wires on the periphery; the diameter of the steel wire rope is 32.5mm). Under the above same control strategy, the measured maximum offset is 3.4mm (H g = 800mm, ΔL = 0.15H g ), which is far lower than the critical threshold.

[0034] In the above technical solution, as the cutting depth increases, the bearing capacity of the remaining cross-section of the column gradually decreases. If the matching of the cutting rate and the hoisting prestress is insufficient, it may cause the column to gradually tilt under the action of gravity or external loads (such as wind load). Therefore, innovative improvements have been made during the static cutting process, and the critical value of the offset ΔL is set to 0.15Hg , indicating that a limited and controllable slight inclination of the column body is allowed during the cutting process. In addition, the timing of applying prestress is also improved. After h reaches the critical threshold, the wire saw feeding rate is reduced to 50 - 60% of the initial value, slowing down the weakening speed of the remaining cross-section, providing stress redistribution time for the hoisting system, being able to accurately offset the overturning moment caused by cutting, and reducing the risk of sudden inclination.

[0035] Specifically, the pressure sensors are arranged symmetrically on both side surfaces of the reinforced concrete column along the axial direction of the column, 20 - 30 cm above the predetermined cutting line (avoiding the heat-affected zone of cutting). The pressure sensors are used to monitor the change in the axial pressure distribution of the remaining cross-section of the column body during the cutting process, reflecting the load transfer state.

[0036] Specifically, the displacement sensors include a horizontal displacement sensor and a vertical displacement sensor; the horizontal displacement sensor is installed on the side surface of the reinforced concrete column body 10 - 15 cm above the cutting line to monitor the lateral offset; the vertical displacement sensor is installed at the center point of the column top to monitor the vertical settlement, and captures the deformation caused by cutting in real time to prevent sudden inclination. Among them, the axis of the horizontal displacement sensor is parallel to the predetermined cutting plane, and the axis of the vertical displacement sensor is orthogonal to the axis of the horizontal displacement sensor.

[0037] Specifically, in order to avoid the direct impact of cutting vibration on the vertical displacement sensor and affect the detection accuracy, the vertical displacement sensor is a laser emitter and a reflecting target. Among them, the laser emitter is installed adjacent to a stable structure (such as an undemolished floor slab, independent pile foundation), with a horizontal distance of 5 - 10 m from the column body to be cut, and a reflecting target is installed on the top of the column body to be cut, forming a non-contact measurement to avoid interfering with the cutting operation.

[0038] Specifically, the calculation method of the column body offset ΔL in S35 includes: The horizontal displacement sensor real-time collects the lateral offset ΔL at 10 - 15 cm above the cutting line h , and the vertical displacement sensor real-time collects the vertical settlement ΔL of the center point of the column top v ; Calculate the total offset effect during the column body toppling process: , where H is the total height of the reinforced concrete column, and H' is the height difference from the vertical displacement sensor to the cutting line (i.e., H' = H - cutting line height). In this technical solution, the two sensors cooperate to achieve accurate quantification of the inclination state. By converting ΔL according to the height ratio v, avoid ignoring the amplification effect of the settlement at the top of the column on the toppling moment. Specific implementation requirements: The sensor needs to be calibrated at zero before cutting (collect 10 groups of data in a static environment and take the average value); when installing the vertical displacement sensor, the laser transmitter should be fixed on an independent reference pile to avoid interference from surrounding vibrations.

[0039] The present invention also provides a control system for the construction method of the protective demolition of the factory building, as Figure 4 shown, including: A sensor module, which is composed of at least two groups of axial pressure sensors and displacement sensors installed on both sides of the predetermined cutting area of the reinforced concrete column; A wire saw parameter acquisition module, which is a linear velocity sensor and a timer integrated on the drive motor of the wire saw cutting machine, and is used to obtain the cutting linear velocity v and the effective cutting time t in real time; A data communication module, which sends the data of the sensor module and the wire saw parameter acquisition module to the central control unit through wired / wireless transmission; A central control unit, in which a calculation module is set. The calculation module pre-stores the material strength coefficient k and the cutting efficiency coefficient η, and executes the real-time operation of the formula h = η·v·t·(F / k) 0.5 , and outputs the cutting depth h and the critical state determination signal; the central control unit synchronously coordinates the wire saw and the lifting equipment, can respond quickly, and the cutting efficiency is increased by 2.5 times (it takes 1.8 h to demolish a single column using the solution in this plan, and it takes 4.5 h to cut a single column using the traditional wire saw).

[0040] An execution module, including a lifting equipment controller and a wire saw feed rate regulator. After receiving the critical state determination signal, the lifting equipment controller controls the lifting rigging to apply a prestress of 0.2 - 0.3 times the self-weight of the column, and at the same time the wire saw feed rate regulator reduces the cutting rate to 50 - 60% of the initial value; A safety redundancy module, when the displacement sensor detects that ΔL ≥ 0.15H g , it triggers an emergency stop instruction to cut off the power supply of the wire saw and activate the lifting synchronization program.

[0041] Taking Workshop 1 as an example: 30 I-shaped reinforced concrete columns are demolished protectively. After the completion of the main structure of the new building, 20 I-shaped columns are selected and moved to the new forum main venue for use as decorative components and do not bear structural loads. During the demolition of 30 I-shaped reinforced concrete columns in the Workshop 1 project, there are no tipping accidents throughout the process, the structural displacement is < 5 mm, the total construction period is shortened by 45%, the cost is saved by 1.2 million yuan, about 180 tons of construction waste is reduced, and the carbon emission is reduced by 30%.

[0042] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A construction method for protective demolition of a factory building, characterized in that: The following steps are involved: S1. Demolition of roof and walls; S2. Destructive demolition is used for reinforced concrete columns that do not need to retain the column structure. Destructive demolition of reinforced concrete columns is carried out mechanically one by one using an excavator; S3. Protective demolition is adopted for reinforced concrete columns that need to retain the complete structure of the reinforced concrete column. Before protective demolition of reinforced concrete columns, the roots of the I-shaped column corbels are tied with steel wire ropes and tied firmly, and then slowly lifted with lifting equipment; then, a 1:0.5 slope excavation is carried out within a certain range of the column foot of the concrete column to expose part of the column foot, and the loose soil is cleaned manually, and then the concrete column is statically cut with a rope saw cutter; The static cutting of the concrete column by using a rope saw in S3 specifically comprises the following steps: S31, installing a pressure sensor and a displacement sensor in a predetermined cutting area of ​​a reinforced concrete column, and collecting the axial pressure value F and the column offset ΔL in real time during the cutting process; S32, obtaining the cutting line speed v in real time through the line speed sensor of the wire saw cutting machine, and recording the effective cutting time t by a timer; S33, the linear velocity v, cutting time t and axial pressure value F are input into the central control unit, and the pre-stored material strength coefficient k and cutting efficiency coefficient η are used according to the formula h=η·v·t·(F / k) 0.5 Calculate the real-time cutting depth h; S34, when the calculated cutting depth h reaches the critical cutting depth H g When the weight of the column reaches 80-90%, the lifting slings of the lifting equipment are controlled to apply prestress to 0.2-0.3 times the deadweight of the column, and the feed rate of the wire saw cutting machine is adjusted to 50-60% of the initial rate simultaneously; S35, continuously monitor the column offset ΔL, when ΔL≥0.15H g When the cutting is stopped, the synchronous lifting procedure of the hoisting equipment is started immediately, and the directional transfer is carried out after the cut section is completely separated.

2. The construction method for protective demolition of a factory building as claimed in claim 1, characterized in that: The S1 specifically includes: S11. Protection and reinforcement construction, adopt the steel pipe scaffolding protection, and the structural columns that need to be retained shall be reinforced first, specifically: add column supports to the first span structural columns and the last span structural columns, retain all the original column supports, connect tie rods horizontally between the structural columns of each span, and then fix the upper part of the column foot and the lower part of the corbel of the column support to the structural column in the form of a hoop; S12. Demolition work: S12a, roof dismantling: separate the prefabricated panels and ring beams piece by piece, lift the panels with a crane, and lower them to the ground for recycling or crushing; S12b, wall demolition: the wall is demolished from top to bottom, and the demolition height each time does not exceed 1000mm. The brick slag after demolition is transported by excavator to the designated place on site for storage and used for paving temporary access roads on site; S12c. Dismantling of steel roof trusses: From top to bottom, first non-load-bearing and then load-bearing, use a crane to pre-tension the steel frame upwards, release the steel frame connection points one by one, and then lower it steadily to the ground.

3. The construction method for protective demolition of a factory building as claimed in claim 2, characterized in that: The support between the columns of the first span and the last span and the connection of the tie rods between the columns in S11 specifically include: vertical poles, longitudinal horizontal poles, transverse horizontal poles, brackets and figure-eight diagonal rods; the vertical poles, longitudinal horizontal poles and transverse horizontal poles are combined to form a scaffolding body, and the scaffolding body is connected to the original concrete structure columns through the brackets, and the figure-eight diagonal rods are tied and fixed to the original concrete structure columns on both sides thereof.

4. The construction method for protective demolition of a factory building as claimed in claim 1, characterized in that: The pressure sensors are symmetrically arranged on the surfaces of both sides of the reinforced concrete column along the axial direction of the reinforced concrete column, 20-30 cm above the predetermined cutting line.

5. The construction method for protective demolition of a factory building as claimed in claim 4, characterized in that: The displacement sensor includes a horizontal displacement sensor and a vertical displacement sensor; the horizontal displacement sensor is installed on the side of the reinforced concrete column 10-15 cm above the cutting line to monitor the lateral offset; the vertical displacement sensor is installed at the center point of the top of the column to monitor the vertical settlement.

6. The construction method for protective demolition of a factory building as claimed in claim 5, characterized in that: The vertical displacement sensor is a laser emitter and a reflective target, wherein the laser emitter is installed near a stable structure, with a horizontal distance of 5-10m from the column to be cut, and a reflective target is installed on the top of the column to be cut.

7. The construction method for protective demolition of a factory building as claimed in claim 6, characterized in that: The calculation method of the column offset ΔL in S35 includes: The horizontal displacement sensor collects the lateral offset ΔL at 10-15cm above the cutting line in real time h , the vertical displacement sensor collects the vertical settlement ΔL of the center point of the column top in real time v ; Calculate the total deflection effect during column tipping: , where H is the total height of the reinforced concrete column and H' is the height difference from the vertical displacement sensor to the cutting line.

8. A control system for the construction method for protective demolition of a factory building according to any one of claims 4 to 7, comprising: A sensor module, comprising at least two sets of axial pressure sensors and displacement sensors installed on both sides of a predetermined cutting area of ​​a reinforced concrete column; The wire saw parameter acquisition module is integrated with the wire speed sensor and timer on the driving motor of the wire saw cutting machine, and is used to obtain the cutting wire speed v and the effective cutting time t in real time; A data communication module, which sends the data of the sensor module and the rope saw parameter acquisition module to the central control unit through wired / wireless transmission; The central control unit is provided with a calculation module, which pre-stores the material strength coefficient k and the cutting efficiency coefficient η, and executes the formula h=η·v·t·(F / k) 0.5 Real-time calculation, and output cutting depth h and critical state judgment signal; An execution module, including a hoisting equipment controller and a wire saw feed rate regulator. After receiving a critical state determination signal, the hoisting equipment controller controls the hoisting sling to apply a prestress of 0.2-0.3 times the deadweight of the column, and the wire saw feed rate regulator reduces the cutting rate to 50-60% of the initial value; Safety redundancy module, when the displacement sensor detects ΔL ≥ 0.15H g When the emergency stop command is triggered, the wire saw power supply is cut off and the synchronous lifting program of the hoisting is activated.

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