Construction method for removing bracket concrete through high-pressure water jet

Abstract

The invention discloses a construction method for removing bracket concrete through high-pressure water jet. The construction method comprises the following steps that S1, construction preparation is made; s2, completing installation and construction of the high-pressure water jet system; s3, parameters of the high-pressure water jet system are set; s4, starting to carry out experimental breaking; and S5, starting formal breaking. The concrete is of a microporous structure, the ultimate strength of the concrete is far smaller than the compressive strength of the concrete when the concrete bears tensile stress, the reinforcing steel bars have the characteristics of high tensile strength, dense surfaces of the reinforcing steel bars, no micropores and incapability of drilling in high-pressure water, so that high-pressure water flow is injected into the surface of the concrete, and when the high-pressure water flow penetrates through concrete pores, internal pressure is generated; when the internal pressure exceeds the tensile resistance of the concrete, the concrete is broken and separated, and the internal reinforcing steel bars are not damaged, so that the aims of protecting the reinforcing steel bars from being damaged due to the removal of the concrete and completely removing the concrete are fulfilled, and the construction quality is effectively ensured.

Description

Technical Field

[0001] The invention relates to the field of concrete demolition, in particular to a construction method for demolishing corbel concrete using high-pressure water jets. Background Art

[0002] In the prior art, the demolition methods commonly used in water conservancy project demolition operations are excavator breakers, pneumatic picks, and impact drills. Although the demolition of buildings (structures) can be completed, the process is dusty and vibrates greatly, the construction efficiency is low in small, narrow and certain delicate areas, and the demolition control surface is difficult to guarantee.

[0003] For example, when dismantling the defective support bracket concrete of some old dams in the last century, since the dam bracket is an important part of the dam structure, its main function is to connect the cantilever beam and the hanging beam and transfer the load from the hanging beam. When dismantling this part, the relevant units require that the original steel bars be retained, and the steel bars must not be damaged during the dismantling process, and the concrete attached to the steel bars must be cleaned up. The current conventional construction and demolition methods cannot meet this requirement and need to be improved. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a construction method for removing corbel concrete using a high-pressure water jet to remove concrete on steel bars while leaving the steel bars intact.

[0005] The technical solution of the present invention is as follows: A method for removing corbel concrete by high-pressure water jetting, characterized in that it comprises the following steps:

[0006] S1. Make good preparations for construction, set up temporary protective facilities at the work site, and remove all kinds of debris on the construction site;

[0007] S2. Connect the high-pressure pump with the corresponding hydraulic breaking equipment and other related systems to complete the installation and construction of the high-pressure water jet system;

[0008] S3. Setting the parameters of the high-pressure water jet system according to the on-site construction conditions;

[0009] S4. Start the experimental demolition, where the initial pressure of the high-pressure water jet is 60Mpa, and the jet lasts for 10 to 20 seconds. After checking that there is no abnormality in the mechanical equipment, the pressure is increased to 80Mpa and the jet lasts for 10 to 20 seconds. After checking that there is no abnormality in the mechanical equipment, the pressure is increased to 100Mpa and the jet lasts for 10 to 20 seconds. The cycle test increases the pressure by 20Mpa each time until the concrete can be demolished;

[0010] S5. Formal demolition begins. According to the construction parameters adjusted during the trial demolition, construction officially begins to meet the concrete demolition requirements. During demolition, according to the on-site construction conditions and environment, a manual handheld spray gun is used. The spray gun is fixed to the scaffolding by a safety lock. The operator wears protective clothing and manually rotates the spray gun to adjust the spray position (it can be rotated 10° to 15°). A gun nozzle with an aperture of 1.8mm and a gun body length of about 1.2 to 1.5m is selected. The long gun is replaced in the deep concrete to shoot out 80 to 100Mpa of high-pressure water to break the concrete.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. Since concrete has a multi-microporous structure and its ultimate strength when subjected to tensile stress is much smaller than its compressive strength, and the steel bar is characterized by its strong tensile strength, and the steel bar surface is dense and has no micropores, high-pressure water cannot penetrate. Therefore, this method uses high-pressure water flow to inject into the concrete surface. When the high-pressure water flow penetrates the concrete pores, internal pressure is generated. When the internal pressure exceeds the tensile strength of the concrete, the concrete is broken and separated, and the internal steel bars are not damaged. This achieves the purpose of protecting the steel bars from being damaged by the removal of the concrete and also allowing the concrete to be completely removed, effectively ensuring the construction quality.

[0013] 2. This method only requires a handheld spray gun to remove concrete during construction. Compared with mechanical and manual chiseling of concrete, the construction efficiency is high, especially in areas with dense steel bars. Manual chiseling of concrete has high technical requirements for operators, a long construction period, and it is difficult to ensure the removal quality. High-pressure water jet crushing can immediately remove any place where the water flow can reach, and there is no need to worry about the water flow damaging the steel bars. It shortens the construction period, reduces the construction difficulty, simplifies the construction process, makes the operation flexible, convenient and fast, and saves labor and machinery costs.

[0014] 3. This method uses water flow operations. Compared with conventional demolition operations, it does not require sprinkling water to reduce dust, and the water quality requirements are not high. Rainwater, car washing water, etc. can be collected for water jet operations; compared with mechanical, pneumatic picks, and impact drills, which have high noise and large coordination workload, water flow demolition operations are noise-free, environmentally friendly and pollution-free, and are conducive to safe and civilized construction.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work:

[0017] Figure 1 It is a schematic flow chart of the method of the present invention;

[0018] Figure 2 It is a schematic diagram of the breaking principle of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "vertical", "circumferential", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] like Figure 1 A high-pressure water jetting method for removing corbel concrete is shown, comprising the following steps:

[0023] S1. Make good preparations for construction. Set up temporary protective facilities to prevent concrete debris from splashing into the outer construction area; remove all kinds of debris from the construction surface to ensure that there are no obstacles when the high-pressure water jet equipment is in operation.

[0024] S2. Connect the high-pressure pump with the corresponding hydraulic breaking equipment and other related systems to complete the installation of the high-pressure water jet system.

[0025] S3. Set the parameters of the high-pressure water jet system according to on-site construction conditions.

[0026] The key technology of high-pressure water jetting lies in the setting of parameters. The main parameters of high-pressure water jetting system for hydraulic breaking are water pressure, water flow and water exposure time. The water pressure depends on the nozzle flange and water flow. The water flow is adjusted by changing the speed of the diesel engine or electric motor of the high-pressure pump station. The water exposure time (the time the concrete is exposed to water) depends on the moving speed, reciprocating speed and number of reciprocating of the nozzle rack. Under the condition of constant water pressure and water flow, the water exposure time determines the breaking depth of the concrete. During on-site construction, the water pressure, water flow and water exposure time and other parameters are adjusted according to the concrete strength and breaking depth.

[0027] S4. Start the experimental breaking, where the initial pressure of the high-pressure water jet is 60Mpa, and the jet lasts for 10 to 20 seconds. After checking that there is no abnormality in the mechanical equipment, the pressure is increased to 80Mpa, and the jet lasts for 10 to 20 seconds. After checking that there is no abnormality in the mechanical equipment, the pressure is increased to 100Mpa, and the jet lasts for 10 to 20 seconds. The cycle test increases the pressure by 20Mpa each time until the concrete can be broken. The upper limit of the water flow pressure of mechanical equipment such as spray guns and pump stations can reach 280Mpa. According to the strength of the on-site corbel concrete and relevant construction experience, the water flow pressure of 80 to 100Mpa is generally enough to break the concrete.

[0028] S5. Start the formal demolition. According to the construction parameters adjusted for the experimental demolition, the construction officially begins to complete the concrete demolition requirements. During the demolition, according to the on-site construction conditions and construction environment, a manual handheld spray gun is used for construction. The spray gun is locked and fixed on the scaffolding by a safety lock. The operator wears protective clothing and manually rotates the spray gun to adjust the spray position (it can be rotated 10° to 15°). The aperture of the gun nozzle is 1.8mm, and the gun body length is about 1.2 to 1.5m. The long gun is replaced in the deep concrete, and 80 to 100Mpa high-pressure water flow is ejected to break the concrete. Most of the water flow pressure is borne by the demolished concrete, and the personnel wear protective clothing mainly to prevent splash damage from concrete debris residues.

[0029] During actual construction, the voltage, various parameters, pipeline and equipment conditions must be checked before each operation begins, and construction personnel must be assigned to be responsible for moving the equipment, checking the connections between pipelines, adjusting the equipment pressure in real time, and observing the operation of the high-voltage equipment.

[0030] After the construction is completed every day, the construction site is cleaned up and the demolished concrete is cleaned up. According to the actual situation on site and construction needs, it can be used as backfill material, or cleaned and transported out of the construction site by dump trucks. The dump trucks transporting the demolished concrete must be 100% closed and not overloaded. They must slow down on uphill and downhill roads and turning areas, and send people to clean along the route to ensure the cleanliness of the off-site construction environment.

[0031] Specifically, the working principle of this method is as follows Figure 2 As shown in the figure, concrete has a multi-microporous structure with high comprehensive bonding strength, but the ultimate strength of concrete under tensile stress is much smaller than its compressive strength. The tensile strength of concrete is 1 / 10 to 1 / 20 of its compressive strength. High-pressure water of up to 280Mpa can be generated by a high-pressure pump and injected into the concrete surface through a nozzle. When the high-pressure water penetrates the pores of the concrete, internal pressure is generated. When the internal pressure exceeds the tensile strength of the concrete, the concrete is broken and separated.

[0032] The characteristics of steel bars are strong tensile strength and a dense surface without micropores, so high-pressure water cannot penetrate. Therefore, the steel bars are not damaged at all. This allows the concrete attached to the steel bars to be cleaned spotlessly without damaging the steel bars. This not only protects the steel bars from being damaged by the removal of concrete, but also allows the concrete to be completely removed, effectively ensuring the construction quality.

[0033] This method only requires a handheld spray gun to remove concrete during construction. Compared with mechanical and manual chiseling of concrete, the construction efficiency is high, especially in areas with dense steel bars. Manual chiseling of concrete has high technical requirements for operators, a long construction period, and it is difficult to ensure the removal quality. High-pressure water jet crushing can immediately remove any place where the water flow can reach, and there is no need to worry about the water flow damaging the steel bars. It shortens the construction period, reduces the construction difficulty, simplifies the construction process, makes the operation flexible, convenient and fast, and saves labor and machinery costs.

[0034] This method uses water flow operations. Compared with conventional demolition operations, it does not require sprinkling water to reduce dust, and the water quality requirements are not high. Rainwater, car washing water, etc. can be collected for water jet operations. Compared with mechanical, pneumatic picks, and impact drills that have high noise and large coordination workload, water flow demolition operations are noise-free, environmentally friendly and pollution-free, and are conducive to safe and civilized construction.

[0035] According to statistical calculations, the construction period of removing each corbel concrete by this method is about 2 to 3 days, and the total construction period is 20 days to remove 8 corbels. If conventional machinery is used in combination with manual removal, the corbel is located at an elevation of 8m from the ground, the working surface is limited, and the concrete attached to the original steel bars must be completely removed. It is necessary to manually remove the concrete attached to the steel bars one by one. The steel bar spacing is limited and not easy to operate. According to this schedule, the construction period of each corbel takes at least 15 days, which requires a high level of operation of the operators, and it is difficult to completely remove the concrete. This method takes less than 3 working days on average, which is 12 days faster than mechanical labor, saving 100 working days. In addition, during the removal process, the junction of the new and old concrete can be directly roughened by high-pressure water jets, without the need for secondary roughening, which greatly improves work efficiency, saves labor and machinery, speeds up construction progress, and has good economic benefits.

[0036] In addition to being used to remove corbel concrete, this method can also be used to break concrete pavements, open holes, remove deteriorated concrete; remove resin and mortar from bridge expansion joints; remove locally deteriorated concrete from abutments and piers; crush concrete from building beams, slabs, and columns; remove deteriorated concrete from narrow parts of structures; and roughen the interface between new and old concrete.

[0037] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for removing corbel concrete by high-pressure water jetting, characterized in that: The following steps are involved: S1. Make good preparations for construction, set up temporary protective facilities at the work site, and remove all kinds of debris on the construction site; S2. Connect the high-pressure pump with the corresponding hydraulic breaking equipment and other related systems to complete the installation and construction of the high-pressure water jet system; S3. Setting the parameters of the high-pressure water jet system according to the on-site construction conditions; S4. Start the experimental demolition, where the initial pressure of the high-pressure water jet is 60Mpa, and the jet lasts for 10 to 20 seconds. After checking that there is no abnormality in the mechanical equipment, the pressure is increased to 80Mpa and the jet lasts for 10 to 20 seconds. After checking that there is no abnormality in the mechanical equipment, the pressure is increased to 100Mpa and the jet lasts for 10 to 20 seconds. The cycle test increases the pressure by 20Mpa each time until the concrete can be demolished; S5. Formal demolition begins. According to the construction parameters adjusted during the trial demolition, construction officially begins to meet the concrete demolition requirements. During demolition, according to the on-site construction conditions and environment, a manual handheld spray gun is used. The spray gun is fixed to the scaffolding by a safety lock. The operator wears protective clothing and manually rotates the spray gun to adjust the spray position (it can be rotated 10° to 15°). A gun nozzle with an aperture of 1.8mm and a gun body length of about 1.2 to 1.5m is selected. The long gun is replaced in the deep concrete to shoot out 80 to 100Mpa of high-pressure water to break the concrete.

2. The method for removing corbel concrete by high-pressure water jetting according to claim 1 is characterized in that: In step S3, the main parameters of the high-pressure water jet system for hydraulic breaking are water pressure, water flow and water exposure time. The water pressure depends on the nozzle flange and water flow. The water flow is adjusted by changing the speed of the diesel engine or motor of the high-pressure pump station. The water exposure time depends on the moving speed, reciprocating speed and number of reciprocating of the nozzle rack. During on-site construction, the water pressure, water flow and water exposure time parameters are adjusted according to the concrete strength and breaking depth.

3. The method for removing corbel concrete by high-pressure water jetting according to claim 1 is characterized in that: Before starting each operation, the voltage, various parameters, pipeline and equipment conditions must be checked, and construction personnel must be assigned to be responsible for moving the equipment, checking the connections between pipelines, adjusting the equipment pressure in real time, and observing the operation of the high-voltage equipment.

4. The method for removing corbel concrete by high-pressure water jetting according to claim 1 is characterized in that: After the construction is completed every day, the construction site is cleaned up and the demolished concrete is cleaned up. According to the actual situation on site and construction needs, it can be used as backfill material, or cleaned and transported out of the construction site by dump trucks. The dump trucks transporting the demolished concrete must be 100% closed and not overloaded. They must slow down on uphill and downhill roads and turning areas, and send people to clean along the route to ensure the cleanliness of the off-site construction environment.

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