Construction method of existing brick-laid combined flow underdrain rain and sewage separation

Abstract

This invention discloses a construction method for separating rainwater and sewage in existing brick-built combined sewer systems, belonging to the field of rainwater and sewage separation technology. This construction method for separating rainwater and sewage in existing brick-built combined sewer systems is carried out on the basis of the existing brick-built combined sewer system. It can complete the rainwater and sewage separation transformation of the sewer without completely demolishing the existing combined sewer system structure. This achieves the effects of reducing road excavation and pipeline relocation, reducing project costs, improving construction efficiency, and reducing adverse impacts on the surrounding traffic and social environment.

Description

Technical Field

[0001] This invention relates to the field of rainwater and sewage separation technology, and in particular to a construction method for rainwater and sewage separation in existing brick-built combined sewer systems. Background Technology

[0002] Many municipal roads and older residential areas in urban areas suffer from widespread combined sewer overflows due to their age, negatively impacting the living environment of the city and surrounding areas. With urban development, the renovation of urban sewer systems to separate stormwater and sewage is urgently needed. Regardless of the degree of misconnection or mixing of pipes, any instance of sewage entering stormwater pipes or stormwater entering sewage pipes will cause some degree of adverse effects. The current drainage system is a separate stormwater and sewage system, where stormwater and sewage are discharged separately. Stormwater flows into natural water bodies through stormwater pipes, while sewage flows into sewage treatment plants through sewage pipes. Therefore, it is necessary to renovate the combined sewer overflows in older urban areas to separate stormwater and sewage.

[0003] Underground drains are one of the more challenging aspects of rainwater and sewage separation renovation. Most underground drains are located near urban municipal roads and old residential areas. Once renovation begins, road excavation is inevitable, which will inevitably have certain adverse effects, causing road congestion, increasing urban traffic pressure, and affecting the normal life and travel of surrounding residents. Summary of the Invention

[0004] The purpose of this invention is to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a construction method for the separation of rainwater and sewage in existing brick-built combined sewer systems, which can reduce road excavation and pipeline relocation, reduce project costs, improve construction efficiency, and reduce adverse impacts on surrounding traffic and the social environment.

[0005] The construction method for existing brick-built combined sewer systems with separate storm and sewage drainage according to embodiments of the present invention includes:

[0006] Step 1: Use physical measures such as airbags to temporarily seal both ends of the culvert to create a closed construction space;

[0007] Step 2: Utilize equipment such as DC blowers to effectively ventilate the culvert for at least half an hour. Construction personnel may only enter the culvert after the concentration of toxic gases detected in the culvert reaches the safety standard; and safety measures such as wearing respirators and oxygen masks must be taken. Continuous ventilation must be carried out during construction to ensure the personal safety of construction personnel.

[0008] Step 3: Clean and dredge the culvert using manual or hydraulic dredging methods, removing all silt, bricks, stones, and other residues from the culvert.

[0009] Step 4: Assess the safety of the culvert based on its dimensions, surface flatness, structural damage, surrounding land conditions, and geological conditions.

[0010] Step 5: Reinforce the culvert based on the results of the safety assessment;

[0011] Step 6: Construct the sewage pipes while ensuring the stability of the brick-built combined sewer walls and arch.

[0012] Step 7: Install inspection wells at regular intervals along the sewage pipes;

[0013] Step 8: Install a connection well on the side of the inspection well where sewage connection is required. The connection well should be located close to the edge of the culvert and used to connect to other sewage pipes for unified collection and treatment of sewage within the service area. A sedimentation tank should be installed at the bottom of the connection well, with the top flush with the existing ground. The sedimentation tank at the bottom of the connection well should be cleaned regularly. The connection well and the inspection well are connected by a sewage branch pipe. According to the location of the main sewage pipe, a connection port should be reserved on the side wall of the lower part of the connection well, parallel to the axis of the main sewage pipe, for connecting the sewage branch pipe. A certain number of connection ports can be reserved on the other side walls according to the access needs of surrounding sewage pipelines for connecting to other sewage pipes.

[0014] The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to embodiments of the present invention has at least the following beneficial effects: construction on the basis of existing brick-built combined sewer systems can achieve the rainwater and sewage separation transformation of the sewer without completely demolishing the existing combined sewer structure, thereby reducing road excavation and pipeline relocation, lowering project costs, improving construction efficiency, and reducing adverse impacts on surrounding traffic and the social environment.

[0015] According to some embodiments of the present invention, in step 1, during construction, a small water pump can be used as a temporary drainage device to pump the combined water in the upstream culvert to the downstream to ensure its normal discharge, while creating dry construction conditions.

[0016] According to some embodiments of the present invention, in step 2, construction workers need to wear gas-proof oxygen masks, and ventilation work must be carried out continuously during construction.

[0017] According to some embodiments of the present invention, in step 3, for severely silted-up sewers, multiple cleaning and vacuuming processes can be performed to ensure that the sewers can be thoroughly cleaned and their original flow capacity restored.

[0018] According to some embodiments of the present invention, the method also includes dewatering around the culvert, setting up several dewatering wells at a certain distance outside the excavation range of the culvert, and setting up submersible pumps to pump out the groundwater in the wells. The depth of the dewatering wells is not less than the excavation depth of the foundation pit of the culvert bottom slab, and after dewatering, it is ensured that the groundwater level in the construction area is lower than the excavation depth.

[0019] According to some embodiments of the present invention, in step 5, for underground drains with generally low safety, the inner walls and arches of the existing underground drains are treated with wire mesh and shotcrete.

[0020] According to some embodiments of the present invention, in step 5, for underground ditches with poor safety, the inner walls and arches of the existing underground ditches are treated with wire mesh and shotcrete, and temporary steel arches and other structures are added on the basis of wire mesh and shotcrete to enhance the overall rigidity of the structure.

[0021] According to some embodiments of the present invention, in step 6, the sewage pipe is constructed using the inverted arch method. First, the bottom slab of the existing brick-built combined sewer is broken, and the inverted arch is excavated downwards according to its shape. After the excavation is completed, the inverted arch is immediately assembled to close the culvert structure and ensure its stability. After the inverted arch is assembled, the main sewage pipe is laid, and then concrete is backfilled to the designed elevation of the bottom slab of the sewer.

[0022] According to some embodiments of the present invention, in step 6, the sewage pipeline is constructed using the direct excavation method. The center line of the culvert bottom slab is used as the positioning line, and the sewage pipeline trench is excavated vertically downward in sections with baffle support. After the trench is excavated, the sewage pipeline is laid immediately. After the laying is completed, materials such as concrete, plain soil, and gravel can be used to backfill and compact to the bottom of the original culvert bottom slab. Then the culvert bottom slab is restored. The bottom slab is constructed in place using reinforced concrete.

[0023] According to some embodiments of the present invention, the inspection well is a precast reinforced concrete enclosed box structure, with a width not greater than the width of the culvert bottom slab and a length not greater than the excavation advance in one operation; sewage main pipe connection ports are reserved on both sides of the inspection well perpendicular to the axis of the main sewage pipe; sewage branch pipe connection ports are reserved on the side wall parallel to the axis of the main sewage pipe and where sewage connection is required; and an inspection port is reserved in the middle of the top slab for dredging and maintenance of the sewage pipe under special circumstances. A sealed manhole cover is installed on the top of the inspection port to prevent mutual seepage of rainwater and sewage between the upper and lower layers.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0026] Figure 1 This is a cross-sectional schematic diagram of the location of the inspection well in an embodiment of the present invention;

[0027] Figure 2 yes Figure 1 Sectional view of section AA;

[0028] Figure 3This is a schematic cross-sectional view of a non-inspection well location in an embodiment of the present invention (inverted arch method);

[0029] Figure 4 yes Figure 3 Sectional view of section BB;

[0030] Figure 5 This is a cross-sectional schematic diagram of a non-inspection well location in another embodiment of the present invention (direct excavation method);

[0031] Figure 6 yes Figure 5 Sectional view of the CC section.

[0032] Figure label:

[0033] 100mm brick-built combined sewer ditch; 110mm reinforcement and support structure; 120mm ditch bottom slab; 130mm sealed manhole cover; 140mm inspection well; 150mm main sewage pipe; 160mm connecting sewage pipe; 170mm foundation of connecting well; 180mm wall of connecting well; 190mm connecting branch sewage pipe; 200mm soil; 210mm shaft of connecting well; 220mm cover plate of connecting well; 230mm manhole cover of connecting well; 240mm invert arch; 250mm backfill material. Detailed Implementation

[0034] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0037] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0038] Reference Figures 1 to 6 This invention describes a construction method for separating rainwater and sewage in existing brick-built combined sewer systems.

[0039] like Figures 1 to 6 As shown in the embodiment of the present invention, the construction method for existing brick-built combined sewer system with separate storm and sewage drainage includes the following steps:

[0040] Step 1: Use physical measures such as airbags to temporarily seal both ends of the culvert to create a closed construction space;

[0041] Step 2: Utilize equipment such as DC blowers to effectively ventilate the culvert for at least half an hour. Construction personnel may only enter the culvert after the concentration of toxic gases detected in the culvert reaches the safety standard; and safety measures such as wearing respirators and oxygen masks must be taken. Continuous ventilation must be carried out during construction to ensure the personal safety of construction personnel.

[0042] Step 3: Clean and dredge the culvert using manual or hydraulic dredging methods, removing all silt, bricks, stones, and other residues from the culvert.

[0043] Step 4: Assess the safety of the culvert based on its dimensions, surface flatness, structural damage, surrounding land conditions, and geological conditions.

[0044] Step 5: Reinforce the culvert based on the results of the safety assessment;

[0045] Step 6: Construction of the sewage pipes shall be carried out in accordance with the principle of ensuring the stability of the inner wall and arch of the 100mm brick-built combined sewer ditch;

[0046] Step 7: Install inspection wells 140 at certain intervals on the sewage pipe;

[0047] Step 8: Install a connection well on the side of inspection well 140 where sewage connection is required. The connection well is located close to the edge of the culvert and is used to connect to other sewage pipes for unified collection and treatment of sewage within the service area. A sedimentation tank is installed at the bottom of the connection well, and the top is flush with the existing ground. The sedimentation tank at the bottom of the connection well is cleaned regularly. The connection well and inspection well 140 are connected by a sewage branch pipe. According to the location of the main sewage pipe 150, a connection port is reserved on the side wall of the lower part of the connection well, parallel to the axis of the main sewage pipe 150, for connecting to the sewage branch pipe 190. A certain number of connection ports can be reserved on the other side walls according to the access requirements of surrounding sewage pipelines for connecting to other sewage pipes.

[0048] like Figure 1 and Figure 2 As shown, the inner side of the brick-built combined sewer culvert 100 is provided with a reinforcement and support structure 110. The bottom of the brick-built combined sewer culvert 100 is provided with a culvert bottom plate 120, and a sealing manhole cover 130 is installed on the culvert bottom plate 120. An inspection manhole 140 is provided below the brick-built combined sewer culvert 100. A connection manhole is provided on one side of the brick-built combined sewer culvert 100. The connection manhole is connected to the inspection manhole 140 through a connecting sewage pipe 160. The connection manhole includes a connection manhole wall 180. A connection manhole foundation 170 is provided at the lower end of the connection manhole wall 180. A connection manhole cover plate 220 is provided at the upper end of the connection manhole wall 180. A connection manhole cylinder 210 is provided on the connection manhole cover plate 220. A connection manhole cover 230 is provided at the top of the connection manhole cylinder 210.

[0049] The following is a specific construction example illustrating the construction method of the existing brick-built combined sewer system for separating rainwater and sewage:

[0050] 1) Water blocking and diversion. Physical measures such as airbags are used to temporarily seal both ends of the culvert to create a closed construction space. During construction, small water pumps can be used as temporary drainage equipment to pump the combined water in the upstream culvert to the downstream to ensure its normal discharge and create dry construction conditions.

[0051] 2) Ventilation. Utilize DC blowers and other equipment to effectively ventilate the culvert for at least half an hour. Construction personnel may only enter the culvert after the concentration of toxic gases detected in it has reached a safe level, and must take safety measures such as wearing respirators. Continuous ventilation must be carried out during construction to ensure the personal safety of construction personnel.

[0052] 3) Dredging. Manual or hydraulic dredging methods are used to clean and unclog the culverts, removing all silt, bricks, and other debris. For severely silted culverts, multiple cleaning and vacuuming operations may be performed to ensure thorough cleaning and restoration of original flow capacity.

[0053] 4) Dewatering around the culvert. If the groundwater level is high, several dewatering wells shall be set up at a certain distance outside the excavation area of ​​the culvert, and submersible pumps shall be installed to pump out the groundwater in the wells. The depth of the dewatering wells shall not be less than 120 mm of the excavation depth of the culvert bottom slab. After dewatering, ensure that the groundwater level in the construction area is lower than the excavation depth.

[0054] 5) Safety Level Assessment. The safety of the culvert is assessed based on factors such as its dimensions, surface smoothness, structural damage, surrounding land conditions, and geological conditions. Based on the assessment results, the safety level of the culvert is classified into three grades: good, average, and poor.

[0055] 6) Reinforcement of existing structures in culverts. Based on the safety assessment results from the previous step, culverts with a safety level of "good" do not require reinforcement, while those with a safety level of "average" and "poor" require reinforcement.

[0056] When reinforcing a concealed ditch with a "general" safety level, the existing inner walls and arch of the ditch should be reinforced with wire mesh and shotcrete. When reinforcing a concealed ditch with a "poor" safety level, temporary steel arches or other structures need to be added on top of the wire mesh and shotcrete to enhance the overall structural rigidity.

[0057] 7) Sewage Pipeline Construction. Adhering to the principle of ensuring the stability of the 100mm inner wall and arch of the brick-built combined sewer culvert, a suitable sewage pipeline construction method will be selected based on the actual conditions of the project site. The characteristic dimensions of the sewage pipeline will be determined by the engineering design calculations.

[0058] This invention provides two methods for constructing sewage pipelines:

[0059] The first construction method is as follows: Figure 3 and Figure 4 The inverted arch method shown requires prefabricating concrete inverted arches 240 in advance, taking into account the structural dimensions of the culvert and the design dimensions of the sewage pipe. Construction is then carried out in sections, with the excavation depth of each section controlled within 2 meters. During construction, the existing brick-built combined sewer culvert 100's bottom slab is first removed, and excavation proceeds downwards according to the shape of the inverted arch 240. After excavation, the inverted arch 240 is immediately assembled to close the culvert structure and ensure its stability. After the inverted arch 240 is assembled, the main sewage pipe 150 is laid, and then concrete is backfilled to the design elevation of the culvert bottom slab 120. Inspection wells 140 are installed at certain intervals along the main sewage pipe 150.

[0060] The second construction method is as follows: Figure 5 and Figure 6 The direct excavation method shown also requires segmented construction, with the excavation depth of each segment controlled within 2 meters. During construction, using the center line of the culvert bottom slab 120 as the positioning line, the sewage pipe trench is excavated vertically downwards in segments with baffle support. After the trench is excavated, the sewage pipe is laid immediately. After laying, materials such as concrete, plain soil, and gravel can be used for backfilling and compaction to the bottom of the original culvert bottom slab 120. Then, the culvert bottom slab 120 is restored, and the bottom slab is constructed in place using reinforced concrete. Inspection wells 140 are installed at certain intervals along the main sewage pipe 150.

[0061] The sewage pipe inspection well 140 is a precast reinforced concrete enclosed box structure, with a width not exceeding the width of the culvert bottom slab and a length not exceeding the excavation depth in a single operation. Connection ports for the main sewage pipe 150 are reserved on both sides of the inspection well 140 perpendicular to the axis of the main sewage pipe 150; a connection port for a branch sewage pipe is reserved on the side wall parallel to the axis of the main sewage pipe 150 where sewage connection is required; and an inspection port is reserved in the middle of the top slab for dredging and maintenance of the sewage pipe under special circumstances. A sealed manhole cover 130 is installed at the top of the inspection port to prevent mutual seepage of rainwater and sewage between upper and lower layers.

[0062] 8) Construction of connecting wells

[0063] A connection well is installed on the side of inspection well 140 where sewage connection is required. The connection well is located immediately adjacent to the edge of the culvert and is used to connect to other sewage pipes for unified collection and treatment of sewage within the service area. A sedimentation tank is installed at the bottom of the connection well, with its top flush with the existing ground level. The sedimentation tank at the bottom of the connection well is regularly dredged. The connection well and inspection well 140 are connected by a sewage branch pipe.

[0064] Based on the location of the main sewage pipe 150, a connection port is reserved on the side wall of the lower part of the connection manhole, parallel to the axis of the main sewage pipe 150, for connecting the branch sewage pipe 190. A certain number of connection ports can be reserved on the remaining side walls according to the needs of surrounding sewage pipelines for connecting other sewage pipes.

[0065] In summary, the existing construction method for separating rainwater and sewage in the existing brick-built combined sewer system, which is carried out on the basis of the existing brick-built combined sewer system, can complete the rainwater and sewage separation transformation of the sewer without completely demolishing the existing combined sewer structure. This achieves the effects of reducing road excavation and pipeline relocation, lowering project costs, improving construction efficiency, and reducing adverse impacts on the surrounding traffic and social environment.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A construction method for existing brick-built combined sewer systems with separate storm and sewage drainage, characterized in that, include: Step 1: Use airbags to temporarily seal both ends of the culvert to create a closed construction space; Step 2: Use a DC blower to effectively ventilate the culvert for more than half an hour. Construction personnel may only enter the culvert after the concentration of toxic gas in the culvert has reached the safety standard. Moreover, it is necessary to wear a gas oxygen mask and continuously carry out ventilation during the construction period to ensure the personal safety of the construction personnel. Step 3: Clean and dredge the culvert using manual or hydraulic dredging methods, removing all silt and bricks from the culvert; Step 4: Assess the safety of the culvert based on its dimensions, surface flatness, structural damage, surrounding land conditions, and geological conditions. Step 5: Reinforce the culvert based on the results of the safety assessment; Step 6: To ensure the stability of the inner walls and arch of the brick-built combined sewer culvert, the sewage pipe is constructed using either the invert arch method or the direct excavation method. The invert arch method involves first breaking the existing bottom slab of the brick-built combined sewer culvert, then excavating downwards according to the shape of the invert arch. After excavation, the invert arch is immediately assembled to close the culvert structure and ensure its stability. After the invert arch is assembled, the main sewage pipe is laid, and then concrete is backfilled to the design elevation of the bottom slab of the culvert. The direct excavation method involves using the center line of the bottom slab of the culvert as the positioning line, and excavating the sewage pipe trench vertically downwards in sections with baffle support. After the trench is excavated, the sewage pipe is laid immediately. After laying, concrete, plain soil, and gravel can be used to backfill and compact to the bottom of the original bottom slab of the culvert, and then the bottom slab of the culvert is restored. The bottom slab is constructed in place using reinforced concrete. Step 7: Install inspection wells at regular intervals along the sewage pipes; Step 8: Install a connection well on the side of the inspection well where sewage connection is required. The connection well should be located close to the edge of the culvert and used to connect to other sewage pipes for unified collection and treatment of sewage within the service area. A sedimentation tank should be installed at the bottom of the connection well, with the top flush with the existing ground. The sedimentation tank at the bottom of the connection well should be cleaned regularly. The connection well and the inspection well are connected by a sewage branch pipe. According to the location of the main sewage pipe, a connection port should be reserved on the side wall of the lower part of the connection well, parallel to the axis of the main sewage pipe, for connecting the sewage branch pipe. A certain number of connection ports can be reserved on the other side walls according to the access needs of surrounding sewage pipelines for connecting to other sewage pipes.

2. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, In step 1, during construction, a small water pump can be used as a temporary drainage device to pump the combined water in the upstream culvert to the downstream to ensure its normal discharge and create dry construction conditions.

3. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, In step 2, construction workers must wear oxygen masks and continuously carry out ventilation during construction.

4. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, In step 3, for severely silted-up sewers, multiple cleaning and vacuuming processes can be performed to ensure that the sewers are thoroughly cleaned and their original flow capacity is restored.

5. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, It also includes dewatering around the culvert, setting up several dewatering wells at a certain distance outside the culvert excavation area, and installing submersible pumps to pump out the groundwater in the wells. The depth of the dewatering wells is not less than the excavation depth of the foundation pit of the culvert bottom slab. After dewatering, it is ensured that the groundwater level in the construction area is lower than the excavation depth.

6. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, In step 5, for underground drainage ditches with generally low safety, the inner walls and arches of the existing underground drainage ditches are treated with wire mesh and shotcrete.

7. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, In step 5, for underground trenches with poor safety, the inner walls and arches of the existing underground trenches are treated with wire mesh and shotcrete, and temporary steel arches are added on the basis of wire mesh and shotcrete to enhance the overall structural rigidity.

8. The construction method for separating rainwater and sewage in existing brick-built combined sewer systems according to claim 1, characterized in that, The inspection well is a precast reinforced concrete enclosed box structure, with a width not exceeding the width of the culvert bottom slab and a length not exceeding the excavation depth in a single operation. Sewage main pipe connection ports are reserved on both sides of the inspection well perpendicular to the sewage main pipe axis. Sewage branch pipe connection ports are reserved on the side wall parallel to the sewage main pipe axis where sewage connection is required. An inspection port is reserved in the middle of the top slab for dredging and maintenance of the sewage pipe under special circumstances. A sealed manhole cover is installed at the top of the inspection port to prevent mutual seepage of rainwater and sewage between upper and lower layers.

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