Simple cofferdam for preventing water inrush in pipe jacking construction of river crossing section
By using a simple cofferdam made of steel bars and bamboo strips in the river channel, the problem of water inrush during pipe jacking construction when crossing the riverbed soil layer with a high permeability coefficient was solved, achieving safe and efficient construction results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-18
- Publication Date
- 2026-03-27
AI Technical Summary
When traversing sandy soil layers with high permeability at the bottom of a river, pipe jacking construction can easily cause river water to rush into the pipe jacking machine, posing a safety risk. In addition, traditional methods have long construction cycles and high costs, and are difficult to effectively prevent water inrush accidents.
A simple cofferdam consisting of steel reinforcement supports, bamboo strips, and waterproof tarpaulin was adopted. The steel reinforcement supports were welded to form a skeleton, and the bamboo strips were tied and fixed. The waterproof tarpaulin was covered on the outside of the steel reinforcement supports to form a simple cofferdam that isolates the river water and ensures that the river water is isolated from the pipe jacking construction area.
With its simple structure, low cost, and convenient installation and disassembly, it can effectively prevent river water from flowing in, improve construction safety, ensure that there is no standing water when the pipe jacking passes through the riverbed, eliminate sudden water accidents, and facilitate inspection and patrol.
Smart Images
Figure CN224048189U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of municipal pipeline pipe jacking construction technology, and in particular relates to a simple cofferdam for preventing water inrush during pipe jacking construction in river crossing sections. Background Technology
[0002] In the field of municipal pipeline construction, there are often situations where pipe jacking is carried out across the riverbed. In particular, when the riverbed soil is mainly sandy soil with a high permeability coefficient and the overburden layer on the pipe section is thin, the disturbance of the riverbed during the pipe jacking construction may induce a large amount of river water to rush into the pipe jacking machine, which may lead to the flooding of the pipeline and working well, and the risk of casualties.
[0003] Typically, for pipe jacking construction crossing rivers with a thin overburden layer, methods such as laying impermeable tarpaulins and backfilling with weights within a certain range of the riverbed directly above the pipe jacking location, or setting up temporary cofferdams with steel pipe piles (sheet piles) can be used. However, these methods have long construction periods and high costs, and the riverbed needs to be cleared (or the temporary cofferdam structure needs to be removed) after the pipeline is completed, so they are obviously not the preferred engineering measures.
[0004] In particular, given the thinness of the overburden layer on the pipe section, the high permeability coefficient of the riverbed, and the possibility of river water flowing into the pipe jacking machine, there is an urgent need to develop simple treatment measures and tools.
[0005] Therefore, it is necessary to provide a new simple cofferdam for preventing water inrush during pipe jacking construction in river crossing sections to solve the above-mentioned technical problems. Utility Model Content
[0006] The technical problem solved by this utility model is to provide a simple cofferdam for preventing water inrush during pipe jacking construction in river crossing sections. This cofferdam is simple in structure, low in cost, easy to install and disassemble, ensures that there is no open water around the pipe jacking during riverbed jacking construction, and is easy to inspect and patrol, thus fundamentally preventing water inrush accidents and improving the safety of pipe jacking construction across riverbeds.
[0007] To solve the above-mentioned technical problems, the present invention provides a simple cofferdam for preventing water inrush during pipe jacking construction in river crossing sections, comprising: a steel reinforcement support set on the river channel, with river embankments on both banks of the river channel, and the steel reinforcement support being welded together from two bent steel bars and no less than three straight steel bars;
[0008] The upper part of the bent steel bar is welded with vertically distributed sleeves;
[0009] The number of steel reinforcement supports shall not be less than one. Two steel reinforcement supports shall be assembled into a cofferdam frame that is high in the middle and low on both sides and is symmetrically distributed by connecting steel reinforcements. The two ends of the connecting steel reinforcements shall be provided with short sides perpendicular to the same direction. The two steel reinforcement supports shall be assembled with each other by inserting the two ends of the connecting steel reinforcements into the matching sleeves on the adjacent steel reinforcement supports.
[0010] The outer side of the steel support is bound with several bamboo strips, and the length of the bamboo strips is greater than the length of the straight reinforcement;
[0011] The river channel is provided with a jacking pipe joint, the assembly of the steel support is located directly above the position of the jacking pipe joint in the river channel, the steel supports are fixed by being bound with a plurality of bamboo strips, the outer periphery of the steel supports on both sides is paved with impermeable oil cloth, the upper part of the impermeable oil cloth is higher than the water level line A by not less than 0.5 m, and the river water inside and outside the steel support is isolated to form a simple cofferdam.
[0012] As a further scheme of the utility model, the vertical distance between the top of the curved reinforcement and the lower horizontal section is not less than the total height of the river water depth at the position of the jacking pipe joint plus 0.5 m, at least two straight reinforcements are welded to the lower horizontal section of the curved reinforcement, and at least one straight reinforcement is welded to the top of the curved reinforcement.
[0013] As a further scheme of the utility model, the binding interval of the bamboo strips at the lower horizontal section of the curved reinforcement is 0.3-0.5 m, and the binding interval of the bamboo strips at the curved section of the curved reinforcement is 0.15-0.25 m.
[0014] As a further scheme of the utility model, the number of layers of the impermeable oil cloth is not less than two, and the length of the lower horizontal section of the curved reinforcement is not less than 0.5 times the outer diameter D of the pipe.
[0015] As a further scheme of the utility model, the simple cofferdam is assembled directly above the position of the jacking pipe joint in the river channel, and the vertical symmetry line of the simple cofferdam coincides with the vertical center line of the jacking pipe joint.
[0016] As a further scheme of the utility model, the distance from the starting slope point of the slope section on both sides of the simple cofferdam to the outer wall of the jacking pipe joint is not less than 1.5 times the outer diameter D of the pipe, and the paving length of the impermeable oil cloth on the outer horizontal section of the cofferdam slope section is not less than 2 times the outer diameter D of the pipe.
[0017] Compared with the related art, the water inrush prevention simple cofferdam for pipe jacking construction in a river section has the following beneficial effects:
[0018] 1. The simple cofferdam mainly comprises a support formed by welding steel, bamboo strips and impermeable oil cloth, each component has simple structure, low cost and is convenient to install and disassemble, and the simple cofferdam provides a cheap cofferdam structure for pipe jacking construction in a river section.
[0019] 2. When the simple cofferdam is used, the river water directly above the pipe jacking construction in the cofferdam is pumped dry by a water pump, so that there is no open water within a certain range around the pipe during the jacking construction, and the occurrence of water inrush accidents is fundamentally eliminated, and the safety of the pipe jacking construction through the river bottom is improved.
[0020] 3. When using the simplified cofferdam proposed in this utility model, daily inspections can promptly detect whether external river water has seeped into the cofferdam. If local leakage is found, personnel should be dispatched immediately to investigate and seal the leakage points to ensure that there is no standing water inside the cofferdam and to prevent sudden water inrush accidents. In contrast, the traditional method of laying a seepage-proof membrane tarpaulin close to the riverbed mud surface within a certain range directly above the pipe jacking location cannot be directly judged by visual inspection to determine whether it effectively blocks the flow of river water, and its water-proofing effect is difficult to guarantee. Attached Figure Description
[0021] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0022] Figure 1 Here is a schematic diagram of the proposed support structure;
[0023] Figure 2 This is a schematic diagram of the two support pieces before assembly;
[0024] Figure 3 This is a schematic diagram of the two support pieces after assembly.
[0025] Figure 4 Detailed drawing before assembly of connecting steel bars;
[0026] Figure 5 Detailed drawing of inserting sleeves for connecting reinforcing bars;
[0027] Figure 6 A diagram illustrating the binding of bamboo strips around the support frame;
[0028] Figure 7 A schematic diagram showing the assembled support frame consisting of two bound bamboo strips;
[0029] Figure 8 Schematic diagram of laying waterproof tarpaulin around the bamboo strips of the support frame;
[0030] Figure 9 A schematic diagram showing the assembled support frame with two pieces of oil-proof tarpaulin.
[0031] Figure 10 This is a simplified cross-sectional diagram of a cofferdam.
[0032] Figure 11 A schematic diagram showing the support structure above the location where the pipe jacking crosses the river.
[0033] Figure 12 Schematic diagram of laying impermeable tarpaulin on the support structure above the location where the pipe jacking crosses the river;
[0034] Figure 13 This is a schematic diagram of the cofferdam water level before pipe jacking construction.
[0035] In the figure: 1, curved steel bars; 2, straight bars; 3, sleeves; 4, connecting steel bars; 5, bamboo strips; 6, impermeable oil cloth; 7, jacking pipe sections; 8, embankments; A, water level line; D, outer diameter of the pipe jacking. DETAILED DESCRIPTION
[0036] The utility model will be described further in combination with the drawings and specific embodiments, it is to be noted that, without conflict, the following described embodiments or between the technical features can be arbitrarily combined to form a new embodiment.
[0037] A river-crossing pipe jacking construction water inrush prevention simple cofferdam, its characterized in that: including the steel support of setting on the river course, the two banks of river course are equipped with embankment 8, the steel support is welded by two curved steel bars 1 and no less than three straight bars 2;
[0038] The upper portion of curved steel bar 1 is welded with vertically distributed sleeve 3, the inside of sleeve 3 is hollow, and its inner diameter is slightly larger than the outer diameter of connecting steel bar 4, the upper end of curved steel bar 1 is provided with downward bending short side, and sleeve 3 can be welded outside the vertical short side, as shown in Figure 4 ;
[0039] As shown in Figure 2 and Figure 3 , the number of steel support is not less than 2, and two steel supports are assembled into a cofferdam framework with high middle and low sides by connecting steel bar 4, the two ends of connecting steel bar 4 are provided with vertical short sides in the same direction, and two steel supports are assembled by inserting the two ends of connecting steel bar 4 into the matching sleeves 3 of adjacent steel supports, as shown in Figure 4 and Figure 5 ;
[0040] The diameter of connecting steel bar 4 is preferably the same as that of curved steel bar 1, if the diameter of connecting steel bar 4 is larger, the vertical short sides in the same direction at both ends can be made by welding.
[0041] As shown in Figure 6 and Figure 7 , a plurality of bamboo strips 5 are bound outside the steel support, the length of bamboo strip 5 is greater than that of straight bar 2, the material of bamboo strip 5 is easy to obtain, and the price is low, if smaller diameter bamboo is used instead of bamboo strip 5, it is also feasible;
[0042] The river channel is provided with jacking pipe section 7, the assembly of the reinforcing steel support is located directly above the position of the jacking pipe section 7 in the river channel, a plurality of bamboo strips 5 are used to bind and fix the reinforcing steel supports, the outer periphery of the reinforcing steel supports on both sides is paved with impermeable oil cloth 6, the upper part of the impermeable oil cloth 6 is higher than the water level line A by not less than 0.5 m, and the internal river water and the external river water are isolated from each other to form a simple cofferdam, as shown in Figures 8-10
[0043] As shown in Figure 1 , the vertical distance between the top and the lower horizontal section of the curved reinforcing steel 1 is not less than the total height of the river water depth at the position of the jacking pipe section 7 plus 0.5 m, at least two straight reinforcing steels 2 are welded to the lower horizontal section of the curved reinforcing steel 1, and at least one straight reinforcing steel 2 is welded to the top of the curved reinforcing steel 1, in order to improve the stability of the reinforcing steel support, a certain inclined reinforcing steel can also be welded, in order to save materials, the distribution of the reinforcing steel can be further optimized, and the diameter of the curved reinforcing steel 1 is greater than the diameter of the straight reinforcing steel 2.
[0044] In particular, the vertical distance between the top and the lower horizontal section of the curved reinforcing steel 1 is not less than the total height of the river water depth at the position of the jacking pipe section 7 plus 0.5 m, which refers to the case of the reinforcing steel support during use. During use, the reinforcing steel support will sink into the riverbed silt to a certain depth under the action of the internal and external water pressure difference, so the curved section of the curved reinforcing steel 1 should have sufficient height.
[0045] The reinforcing steel support should have sufficient strength, rigidity and stability to ensure that it does not deform, buckle or even collapse under the action of the water level difference inside and outside the cofferdam.
[0046] The lower horizontal section of the curved reinforcing steel 1 refers to the position that will be in direct contact with the mud surface line B subsequently, and the length thereof is not less than 0.5D (D is the outer diameter D of the jacking pipe section of the jacking pipe section) ;
[0047] As shown in Figure 1 , the bamboo strip binding interval at the lower horizontal section of the curved reinforcing steel 1 is 0.3-0.5 m, and the bamboo strip 5 binding interval at the curved section of the curved reinforcing steel 1 is 0.15-0.25 m.
[0048] The lower horizontal section is closely attached to the riverbed mud surface-mud surface line B, and bears less load, so the interval can be taken as a large value. The bamboo strip 5 at the curved section of the curved reinforcing steel 1 needs to bear the action of the water level difference inside and outside the cofferdam subsequently, so the interval thereof should not be too large.
[0049] The framework system composed of the reinforcing steel support and the bamboo strip 5 has sufficient strength, rigidity and stability to ensure that it does not deform, buckle or even collapse under the action of the water level difference inside and outside the cofferdam.
[0050] As shown in Figure 1 As shown, the number of layers of the impermeable oil cloth 6 is not less than two, and the length of the lower horizontal section of the curved steel bar 1 is not less than 0.5 times the outer diameter D of the pipe.
[0051] If the impermeable oil cloth 6 is overlapped in the direction of the pipe axis (referred to as longitudinal direction), the two pieces of impermeable oil cloth 6 at the overlapping position should be rolled for a length, which is preferably not less than 0.5 m, and other simple measures should be taken to compact and reinforce the longitudinal overlapping position to ensure that no leakage occurs at the overlapping position.
[0052] In the direction of the pipe cross section (referred to as transverse direction), a part of the horizontal section of the impermeable oil cloth 6 is laid on the horizontal section of the steel bar support, and a part is directly laid on the riverbed mud surface. The transverse width of the impermeable oil cloth 6 is relatively narrow, and the impermeable oil cloth 6 is generally not allowed to be overlapped in the transverse direction. At the end of the transverse direction of the impermeable oil cloth 6, the riverbed silt is used for counterpressure and edge locking to ensure that the river water will not leak into the cofferdam through the end of the transverse direction of the impermeable oil cloth 6.
[0053] As shown in Figure 10 , the simple cofferdam is assembled above the position of the jacking pipe section 7 in the river channel, and the vertical symmetry line of the simple cofferdam coincides with the vertical center line of the jacking pipe section 7.
[0054] As shown in Figure 10 , the distance from the starting point of the slope section on both sides of the simple cofferdam to the outer wall of the jacking pipe section 7 is not less than 1.5 times the outer diameter D of the pipe, and the laying length of the impermeable oil cloth on the horizontal section outside the slope section of the cofferdam is not less than 2 times the outer diameter D of the pipe.
[0055] The use method of the simple cofferdam for construction of the pipe crossing river section is as follows:
[0056] (1) Steel bar support is made, and materials such as bamboo strips 5 and impermeable oil cloth 6 are prepared.
[0057] The diameter of the curved steel bar 1 is greater than that of the straight steel bar 2. If the curved steel bar 1 uses thick steel bars (diameter greater than 22 mm), it is not convenient to bend, and a plurality of steel bars can be used to form a generally curved direction as shown in Figure 1 . The straight steel bar 2 can be selected from thin steel bars (diameter 6-10 mm), and the length of the straight steel bar 2 can be 0.8-1.5 m.
[0058] In order to improve the stability of the steel bar support, a certain inclined steel bar can also be welded. The steel bar support should have sufficient strength, stiffness and stability to ensure that it will not be deformed, buckled or even unstable and collapsed under the water level difference between the inside and outside of the cofferdam.
[0059] The length of the bamboo strip 5 can be greater than the length of the straight reinforcement 2 by 0.4-0.8 m, and the width of the bamboo strip 5 can be 6-15 cm. The bamboo strip 5 should not be too narrow (too thin) to ensure that it does not deform too much under the action of water pressure. In particular, when the diameter of the bamboo is small, it is also feasible to use bamboo instead of the bamboo strip 5 and directly bind the bamboo to the steel reinforcement support. When the bamboo strip 5 is bound to the steel reinforcement support, the lengths of the two ends exposed are substantially equal.
[0060] The bound and assembled steel reinforcement support is shown in Figure 7 .
[0061] (2) Arrange and connect the steel reinforcement supports in the river channel.
[0062] Two steel reinforcement supports can be assembled into a cofferdam framework with a high middle and low sides based on the connecting reinforcement 4. The bound and assembled steel reinforcement supports are arranged in the river channel, and the vertical symmetry line of the simple cofferdam coincides with the vertical center line of the pipe section 7, as shown in Figure 10 . The spacing between the steel reinforcement supports is less than the longitudinal width of the steel reinforcement support, and the steel reinforcement supports are bound and fixed to each other by a plurality of bamboo strips 5, as shown in Figure 11 .
[0063] The required number of steel reinforcement supports and the size of the impermeable oil cloth 6 should be calculated according to the width between the river embankments 8 on both sides and the width of the steel reinforcement support.
[0064] (3) Lay the impermeable oil cloth 6 on both sides of the steel reinforcement support.
[0065] The impermeable oil cloth 6 is laid on the outer periphery of the steel reinforcement support on both sides, and the number of layers of the impermeable oil cloth 6 is not less than two. The upper part of the impermeable oil cloth 6 is higher than the water surface by not less than 0.5 m (after the steel reinforcement support is sunk into place), so that the river water inside the steel reinforcement support is isolated from the external river water.
[0066] If the impermeable oil cloth 6 exists in the direction of the pipeline axis (referred to as the longitudinal direction), the two pieces of impermeable oil cloth 6 at the overlapping part should be rolled by a certain length, which should not be less than 0.5 m. Other simple measures should also be used for compaction and reinforcement at the longitudinal overlapping part to ensure that the overlapping part does not leak.
[0067] In the transverse direction of the pipeline cross section (referred to as the transverse direction), part of the horizontal section of the impermeable oil cloth 6 is laid on the horizontal section of the steel reinforcement support, and part of the horizontal section of the impermeable oil cloth 6 is directly laid on the riverbed mud surface. The transverse width of the impermeable oil cloth 6 is relatively narrow, and the impermeable oil cloth 6 is generally not allowed to overlap in the transverse direction. At the transverse end of the impermeable oil cloth 6, the riverbed silt is used for reverse pressure and edge locking to ensure that the river water does not leak into the cofferdam through the transverse end of the impermeable oil cloth 6.
[0068] (4) Before pipe jacking construction, the river water inside the cofferdam is pumped out.
[0069] Before the formal commencement of pipe jacking construction below the cofferdam, water pumps were used to drain the river water inside the cofferdam, exposing the riverbed. This ensured that there was no standing water within a certain range around the pipe jacking site during the construction, fundamentally preventing water inrush accidents and improving the safety of pipe jacking across the riverbed. The water level distribution before pumping was as follows: Figure 11 As shown, the water level distribution after pumping is as follows: Figure 13 As shown.
[0070] During the pipe jacking construction, the inspection and patrol of the cofferdam should be strengthened. Through daily patrols, it can be found in time whether the external river water seeps into the cofferdam. If local leakage is found, personnel should be dispatched in time to investigate and block the leakage point to ensure that there is no open water inside the cofferdam and to prevent the occurrence of water inrush accidents.
[0071] (5) Formal pipe jacking construction.
[0072] According to the design and construction plan, the pipe jacking operation was officially launched until the pipe jacking operation was completed from the starting well to the receiving well.
[0073] If there is standing water inside the cofferdam, pumping operations should be carried out immediately to ensure that there is no standing water inside the cofferdam during the pipe jacking operation. The pumping equipment should be set up inside the cofferdam and its performance should be guaranteed to be good throughout the entire pipe jacking construction period, ready to pump water at any time. However, the traditional practice of laying a seepage-proof membrane tarpaulin close to the riverbed mud surface within a certain range directly above the pipe jacking location cannot be directly judged by visual inspection whether it effectively blocks the flow of river water, and its water-proofing effect is difficult to guarantee effectively.
[0074] (6) Dismantle the simple cofferdam.
[0075] After the pipe jacking operation in the river section is completed, the simple cofferdam is dismantled. First, remove the seepage-proof tarpaulin 6, then remove the bamboo strips 5 binding between each group of steel reinforcement supports, dismantle and lift each steel reinforcement support, leaving no components in the riverbed, restore the river channel, and the construction is completed.
[0076] The proposed simple cofferdam is mainly composed of a support frame formed by welded steel bars, bamboo strips, and waterproof tarpaulin. Each component has a simple structure, low cost, and is easy to install and disassemble. It causes less disturbance to the riverbed and provides an inexpensive cofferdam structure for pipe jacking construction in the river crossing section.
[0077] All standard parts used can be purchased from the market, and can be customized according to the instructions and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the existing technology. The machinery, parts and equipment adopt conventional models in the existing technology, and the structure and principle of the components known to those skilled in the art can be known by those skilled in the art through technical manuals or conventional experimental methods.
[0078] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations or direct or indirect application can be made to these embodiments without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents, and the same is true for the patent protection scope of the utility model.
Claims
1. A simple cofferdam for water inrush prevention in river-crossing pipe jacking construction, characterized in that, The utility model relates to a kind of steel reinforcement support and simple cofferdam for river channel, including: Steel reinforcement support is arranged on river channel, both sides of the river channel are provided with river embankment, and the steel reinforcement support is welded by two curved steel bars and not less than three straight bars; The upper portion of the curved steel bar is welded with vertically distributed sleeve; The number of the steel reinforcement support is not less than two, and two steel reinforcement supports are assembled into cofferdam framework with middle high and both sides low by the connection of connecting steel, the two ends of the connecting steel are provided with perpendicular short side in the same direction, and two steel reinforcement supports are inserted into matching sleeve on adjacent steel reinforcement support by the two ends of the connecting steel respectively to complete mutual assembly; The outer side of the steel reinforcement support is bound with several bamboo strips, and the length of the bamboo strip is greater than the length of the straight bar; The river channel is provided with jacking pipe section, the assembly of the steel reinforcement support is located directly above the position of jacking pipe section in river channel, the steel reinforcement support is fixed by being bound with multiple bamboo strips, and the outer periphery of the steel reinforcement support on both sides is paved with impermeable oil cloth, the upper portion of the impermeable oil cloth is higher than water level line A by not less than 0.5m, and the internal river water and external river water of the steel reinforcement support are isolated to form simple cofferdam.
2. The water bursting prevention simple cofferdam for river-crossing pipe jacking construction according to claim 1, characterized in that: The vertical distance between the top of the curved steel bar and the lower horizontal section is not less than the total height of the river water depth at the position of jacking pipe section plus 0.5m, at least two straight bars are welded at the lower horizontal section of the curved steel bar, and at least one straight bar is welded at the top of the curved steel bar.
3. The simple cofferdam for water inrush prevention in river-crossing pipe jacking construction according to claim 1, characterized in that: The binding interval of the bamboo strip at the lower horizontal section of the curved steel bar is 0.3-0.5m, and the binding interval of the bamboo strip at the curved section of the curved steel bar is 0.15-0.25m.
4. The simple cofferdam for water inrush prevention in river-crossing pipe jacking construction according to claim 1, characterized in that: The number of layers of the impermeable oil cloth is not less than two, and the length of the lower horizontal section of the curved steel bar is not less than 0.5 times the outer diameter D of the pipe.
5. The simple cofferdam for water inrush prevention in river-crossing pipe jacking construction according to claim 1, characterized in that: The simple cofferdam is assembled directly above the position of jacking pipe section in river channel, and the vertical symmetry line of the simple cofferdam coincides with the vertical center line of the jacking pipe section.
6. The simple cofferdam for water inrush prevention in river-crossing pipe jacking construction according to claim 1, characterized in that: The distance between the starting point of the slope section on both sides of the simple cofferdam and the outer wall of the jacking pipe section is not less than 1.5 times the outer diameter D of the pipe, and the paving length of the impermeable oil cloth on the outer horizontal section of the cofferdam slope section is not less than 2 times the outer diameter D of the pipe.