Method for breaking and replacing large-diameter waste concrete sewage pipeline
By using small-diameter pipe grouting reinforcement and layer-by-layer breaking of aerated concrete blocks for backfilling, the problem of abandoned sewage pipelines affecting construction was solved, ensuring safety and ground stability during construction and guaranteeing the smooth progress of the pipe jacking project.
Patent Information
- Application Number
- CN202610080598.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-21
- Publication Date
- 2026-03-06
AI Technical Summary
Before the construction of the underground earth pressure balance pipe jacking project, the abandoned sewage pipeline contained steel bars and high-strength concrete, which made it impossible for the cutterhead to cut and the soil chamber to maintain pressure. Moreover, the sewage pipeline was prone to ground collapse after being broken, which affected the construction safety and progress.
The soil above the sewage pipeline was reinforced by grouting with small pipes. The pipeline was divided into sections and the pipe layers were broken off one by one. Support frames were used for support. The aerated blocks were gradually broken off and backfilled. Grouting was then used to form the top layer for reinforcement to ensure the stability of the stratum.
This ensured safety and ground stability during the removal of abandoned sewage pipelines, prevented ground subsidence, ensured the smooth progress of subsequent pipe jacking construction, and met construction safety requirements.
Smart Images
Figure CN121611212A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of underground pipeline demolition construction technology, specifically to a method for demolishing and replacing large-diameter abandoned concrete sewage pipelines. Background Technology
[0002] In trenchless construction of urban integrated utility tunnels, sewage pipe networks, pedestrian underpasses, subway entrances and transfer passages, underground obstacles such as abandoned pipelines buried in the foundation can hinder construction. Especially before underground earth pressure balance pipe jacking projects, abandoned sewage pipelines often contain reinforcing steel and high-strength concrete, making it impossible for the cutterhead to cut and the earth chamber to maintain pressure. Furthermore, the removal of sewage pipelines can easily cause ground subsidence, jeopardizing the smooth progress of subsequent pipe jacking construction. Summary of the Invention
[0003] To overcome the shortcomings of existing technologies, a method for breaking and replacing large-diameter abandoned concrete sewage pipelines is provided to solve the problems of underground obstacles such as abandoned sewage pipelines before the construction of underground earth pressure balance pipe jacking projects, which prevent the cutter head from cutting and the soil chamber from maintaining pressure, and easily cause ground subsidence after the sewage pipelines are broken.
[0004] To achieve the above objectives, a method for removing and replacing large-diameter abandoned concrete sewage pipelines is provided, comprising the following steps: Grouting reinforcement was carried out on the top soil of the sewage pipeline to be demolished using small guide pipes; Each section of the sewage pipeline is divided into multiple pipe segments, and each pipe segment is divided into multiple pipe layers in the cross-sectional direction of the pipe segment. The multiple pipe layers include a bottom pipe layer, a middle pipe layer, and a top pipe layer. The pipe sections are broken sequentially along the length of the sewage pipeline. When breaking the pipe sections, the bottom layer, middle layer and top layer of the pipe are broken one by one from bottom to top. After breaking the bottom layer, aerated blocks are built in situ to form the top layer, so that the top layer is supported by the upper layer. Grout is injected into the gaps of the aerated blocks in the top layer, so that the aerated blocks in the top layer are reinforced and bonded together.
[0005] Furthermore, before breaking each pipe section, a support frame is installed inside the pipe section, the support frame comprising: The frame is placed at the tail end of the bottom layer of the tube; A support member, one end of which is vertically movable to the top of the frame, one end of which is supported at the rear end of the top tube layer, and the other end of which is supported at the front end of the top tube layer; After a pipe section is broken, the support frame is moved back one construction position so that the other end of the support frame is supported on the top layer of the next pipe section.
[0006] Furthermore, when performing the step of grouting reinforcement with small guide pipes in the top soil of the sewage pipeline to be broken, multiple small guide pipes are arranged in the circumferential 180° direction of the pipe section.
[0007] Furthermore, the small conduit is inclined toward the rear end of the sewage pipeline.
[0008] Furthermore, the inclination angle of the small catheter is 10~15°.
[0009] Furthermore, when constructing the aerated concrete block to form the top layer, solid concrete bricks are used to fill the side pores of the top layer.
[0010] The beneficial effects of this invention are that the method for breaking and replacing large-diameter abandoned concrete sewage pipelines adopts breaking, backfilling, and replacement, which meets the safety technical requirements during construction, ensures the stability of the stratum, and avoids subsidence and collapse of municipal roads near the pipeline, thus preventing safety accidents and economic losses. On the other hand, during subsequent underground earth pressure balance pipe jacking construction, the cutterhead cutting is convenient and the soil chamber pressure is maintained. Attached Figure Description
[0011] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figures 1 to 8 This is a schematic diagram of the structure of the method for breaking down and replacing large-diameter abandoned concrete sewage pipelines according to an embodiment of the present invention.
[0012] Figure label: Sewage pipeline 1, bottom layer a, middle layer b, top layer c; Small catheter 2; Back to top 3; Support frame 4, frame body 41, support component 42. Detailed Implementation
[0013] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0014] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0015] Reference Figures 1 to 8 As shown, where, Figure 1 , Figure 3 , Figure 5 , Figure 7 This is a schematic diagram of the cross-section of a sewage pipeline. Figure 2 , Figure 4 , Figure 6 and Figure 8 This is a schematic diagram of the longitudinal section of a sewage pipeline. Specifically, Figure 2 for Figure 1 A schematic diagram of the longitudinal section of the sewage pipeline in the middle; Figure 4 for Figure 3 A schematic diagram of the longitudinal section of the sewage pipeline in the middle; Figure 6 for Figure 5 A schematic diagram of the longitudinal section of the sewage pipeline in the middle; Figure 8 for Figure 7 A schematic diagram of the longitudinal section of a sewage pipeline. This invention provides a method for removing and replacing large-diameter abandoned concrete sewage pipelines, comprising the following steps: S1. Grouting reinforcement is carried out on the top soil of the sewage pipeline 1 to be demolished using small guide pipes 2.
[0016] Before reinforcing the soil above the sewage pipeline with grouting using small guide pipes, the pipeline is subjected to dewatering, drainage, sludge dilution, sludge suction, high-pressure cleaning, ventilation, sludge removal, ventilation and disinfection before demolition begins.
[0017] When performing the step of grouting reinforcement of the top soil of the sewage pipeline 1 to be demolished, multiple small pipes 2 are laid in the circumferential 180° direction of the pipe section.
[0018] See Figure 1 and Figure 2 As shown, the small conduit 2 is inclined toward the rear end of the sewage pipeline 1. In a preferred embodiment, the inclination angle of the small conduit 2 is 10~15°.
[0019] In this embodiment, grouting is performed by drilling a pilot hole at the top of the sewage pipeline using a hand drill. A small guide pipe is then inserted and grouted at a 180° circumferential angle, with a circumferential spacing of 500mm and a longitudinal spacing of 800mm. The guide pipes are installed at a 10-15° angle forward, and a total of seven guide pipes are installed circumferentially. The grouting pressure should not exceed 1 MPa.
[0020] S2. Divide each section of the sewage pipeline 1 into multiple pipe segments, and divide each pipe segment into multiple pipe layers in the cross-sectional direction of the pipe segment. The multiple pipe layers include the bottom layer a, the middle layer b, and the top layer c.
[0021] S3. Break the pipe sections sequentially along the length of the sewage pipeline 1. When breaking the pipe sections, break the bottom layer a, the middle layer b, and the top layer c of the pipe one by one from bottom to top. After breaking the lower pipe layer, build aerated blocks in situ to form the top layer 3, so that the top layer 3 is supported by the upper pipe layer.
[0022] No less than 12 hours after grouting with small guide pipes, when the strength reaches 1 MPa, and after verification that the soil is well compacted and there is no obvious leakage, the sewage pipeline demolition work can be carried out.
[0023] Before each pipe section is broken up, a support frame 4 is installed inside the pipe section. The support frame 4 includes a frame body 41 and support members 42.
[0024] The frame 41 rests at the tail end of the bottom layer a of the tube. The frame as a whole is a regular cuboid shape.
[0025] The support member 42 includes multiple horizontal bars. These horizontal bars are spaced apart along the circumference of the pipe section. One end of the support member 42 is vertically adjustable to the top of the frame 41. One end of the support member 42 is supported at the rear end of the top pipe layer c. The other end of the support member 42 is supported at the front end of the top pipe layer c.
[0026] After a pipe section is broken, the support frame 4 is moved back one construction position so that the other end of the support frame 4 is supported on the top layer c of the next pipe section.
[0027] After the top layer of the pipe section is supported by the support frame, the pipe is broken up, backfilled, and replaced. Specifically, manual pneumatic hammers are used for breaking up, and the principle of bottom-up, short breaking, and strong support must be followed, with each cycle advancing 2 meters.
[0028] The concrete pipe wall is removed in three layers from bottom to top (bottom layer a, middle layer b, and top layer c), and then backfilled with aerated concrete blocks. The aerated concrete blocks are made of aerated concrete and masonry. The aerated concrete blocks need to be stacked in a staggered and interlocking order.
[0029] During the demolition process, the steel bars of the pipe section were stripped from the concrete and then cut off using a cutting machine / gas cutting; the slag was removed by manually pushing a cart to the opening.
[0030] After each cycle of excavation is completed, aerated concrete blocks are transported from the opening to backfill the cross-section. One cycle (0.67m) of aerated concrete blocks is transported into the pipeline in advance and stacked in a staircase manner for later use, while also serving as construction steps.
[0031] When constructing the aerated concrete block to form the top layer 3, solid concrete bricks are used to fill the side gaps of the top layer 3.
[0032] Each longitudinal demolition range is 0.667m. The vertical demolition is carried out in three layers of 0.8m, 1m and 0.6m. The backfilling is done with B05 aerated concrete blocks and MU15 solid concrete bricks. The gaps are filled with M5 masonry mortar.
[0033] Combination Figure 3 , Figure 5 and Figure 7As shown, the removal of the bottom layer (a), middle layer (b), and top layer (c) of each pipe section includes the following steps: Step 1: Break down the bottom layer of pipe a (the longitudinal length of the bottom layer of pipe a is only 0.667m, and the vertical height of the pipe wall is 0.8m), and use B05 aerated concrete blocks for stacking.
[0034] Step 2: Break through the pipe walls on both sides of the middle layer b (within a height of 1m), and stack B05 aerated concrete blocks. Fill the gaps on the sides and top with solid concrete bricks and mortar.
[0035] Step 3: Break through the inner wall of the top layer of the pipe (c, within a height of 0.6m), backfill with B05 aerated concrete blocks, and seal the top with MU15 solid concrete bricks.
[0036] In this embodiment, the inner diameter of the pipe is 2m, the length of each section is 2m, each longitudinal cycle is 670mm, and 3 cycles constitute one pipe section. After the pipe is supported by a support frame, the inverted arch is first broken, and the lower inverted arch is backfilled with aerated concrete blocks within a height range of 0.8m. Then, the pipe walls on both sides within a height range of 1m are broken, and backfilling continues. Finally, the remaining 0.6m height range is broken, and backfilling is completed for one cycle.
[0037] S4. Grout is injected into the gaps of the aerated blocks in the top layer 3 to reinforce and bond the aerated blocks in the top layer 3 into a whole.
[0038] After each 5-8 meter section of pipe is backfilled, grouting is performed on the voids in the backfilled soil based on ground monitoring data. During each cycle of demolition and backfilling grouting, ground settlement data must be monitored as required, and the grouting volume must be controlled based on the amount of slag discharged after demolishing the pipe wall.
[0039] In this embodiment, a concrete block backfilling and grouting construction method is adopted to achieve the purpose of stabilizing the soil near the pipeline. When backfilling aerated concrete blocks, care should be taken to ensure that the stacking order is staggered to meet the safety requirements during the demolition of large-diameter deep underground concrete pipelines.
[0040] When demolishing large-diameter abandoned underground concrete pipelines, concrete blocks are used for backfilling and replacement to prevent instability and collapse near the pipeline during the demolition process. Some large-diameter abandoned sewage pipelines with a diameter exceeding 1.5m buried deep underground require demolition and replacement. This invention's method for demolishing and replacing large-diameter abandoned concrete sewage pipelines has been successfully implemented, demonstrating reliable safety.
[0041] The sewage pipeline is located above a municipal road. To prevent ground subsidence, a cyclical method of breaking up the pipeline was adopted, while the pipeline area was backfilled and the gaps in the backfill aerated concrete blocks were grouted. The aerated concrete blocks are 600×200×300mm in size, each breaking and replacement section is 670mm in longitudinal length, and three cycles constitute one 2m section of pipeline.
[0042] The method for breaking down and replacing large-diameter abandoned concrete sewage pipelines of the present invention adopts breaking down and backfilling replacement, which meets the safety technical requirements during the construction process, ensures the stability of the stratum, and avoids the subsidence and collapse of municipal roads near the pipeline, thus preventing safety accidents and economic losses.
[0043] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. A method for breaking and replacing a large diameter abandoned concrete sewer line, characterized by, The method comprises the following steps: Small pipe grouting is performed in the top soil of the sewage pipeline to be demolished; Each pipe section of the sewage pipeline is divided into a plurality of pipe segments, and each pipe segment is divided into a plurality of pipe layers in the cross-sectional direction of the pipe segment, including a bottom pipe layer, a middle pipe layer and a top pipe layer; The pipe segments are demolished in sequence along the length direction of the sewage pipeline, and the bottom pipe layer, the middle pipe layer and the top pipe layer are demolished one by one from bottom to top when the pipe segments are demolished, and after the demolition of the lower pipe layer, the return top layer is formed by in-situ masonry of aerated blocks, so that the return top layer is supported on the upper pipe layer; Grouting is performed in the gaps of the aerated blocks of the return top layer, so that the aerated blocks of the return top layer are reinforced and bonded into one body.
2. The method of breaking and replacing a large diameter abandoned concrete sewer line according to claim 1, wherein, Before demolishing each pipe section, a support frame is installed in the pipe section, and the support frame comprises: a frame body resting on the tail end of the bottom pipe layer; a support member, one end of the support member being liftable on the top of the frame body, one end of the support member being supported on the rear end of the top pipe layer, and the other end of the support member being supported on the front end of the top pipe layer; After the demolition of a pipe segment, the support frame is moved backward by one construction position, so that the other end of the support frame is supported on the top pipe layer of the next pipe segment.
3. The method of breaking and replacing a large diameter abandoned concrete sewer line according to claim 1, wherein When the small pipe grouting in the top soil of the sewage pipeline to be demolished is performed, a plurality of small pipes are arranged in the circumferential direction of 180° of the pipe section.
4. The method of breaking and replacing a large diameter abandoned concrete sewer line according to claim 3, wherein, The small pipes are arranged obliquely towards the rear end of the sewage pipeline.
5. The method of breaking and replacing a large diameter, abandoned, concrete sewer line according to claim 4, wherein, The oblique angle of the small pipes is 10-15°.
6. The method of breaking and replacing a large diameter, abandoned, concrete sewer line of claim 1, wherein, When the return top layer is formed by masonry of aerated blocks, the side hole gaps of the return top layer are filled with concrete solid bricks.