Downstream blocking structure for embankment seepage failure and blocking method thereof

Abstract

The application discloses a dam seepage damage downstream plugging structure and a plugging method thereof, and relates to the technical field of dam plugging, which comprises a dam located at the bank of an original river, a seepage channel and a harmful crack formed by flood seepage damage in the dam, a cofferdam arranged at the downstream part of the seepage channel and the harmful crack, and the dam is used for plugging and reinforcing the seepage channel by adopting an upstream plugging backfilling and downstream dam body soil cultivating mode. The application raises the water level downstream by adopting the cofferdam mode, thereby reducing the seepage gradient of the dam body seepage channel. With the lifting of the downstream cofferdam, the seepage gradient is gradually reduced, the seepage damage effect is gradually weakened, the short-term safety of the dam body is significantly improved, the dam body is prevented from being deficient due to seepage damage expansion in a short term, and more favorable conditions are created for the upstream throwing filling plugging.

Description

Technical Field

[0001] This invention relates to the field of dam sealing technology, and in particular to a downstream sealing structure and sealing method for dam seepage damage. Background Technology

[0002] my country has a vast network of rivers, along which numerous towns and villages are situated. To ensure the safety of these towns and villages during floods, dikes are typically used to reinforce and protect the river channels. However, due to inherent structural defects, biological damage, or years of neglect, dikes often experience seepage damage during sudden floods, which gradually expands and eventually leads to their collapse. This damage can then harm surrounding towns and villages, endangering lives and property. When seepage occurs, temporary sealing methods typically involve dumping stones or sandbags upstream, or excavating and backfilling the seepage channel downstream with filters and stones. However, these two traditional emergency sealing methods have significant drawbacks; the sealing often fails, allowing the seepage channel to expand further and eventually breach the dike.

[0003] Existing sealing methods, particularly upstream sealing, suffer from poor effectiveness due to the uncertainty of the seepage channel. This requires expanding the area for dumping gravel and sandbags, while the dumped materials are washed away by the river water, resulting in low sealing efficiency. Furthermore, there is a risk that the seepage channel will continue to expand during the sealing process. Summary of the Invention

[0004] To address the shortcomings of existing upstream sealing methods, such as the uncertainty of seepage channels leading to poor sealing effectiveness, the need to expand the area for dumping gravel and sandbags, the risk of material loss due to river water impact, low sealing efficiency, and the risk of seepage channels continuously expanding during the sealing process, this invention provides a downstream sealing structure and method for preventing seepage damage to dikes.

[0005] This invention provides a downstream sealing structure for seepage damage to a dike, comprising a dike located on the bank of the original river channel, wherein seepage channels and hazardous cracks formed by flood seepage damage are formed within the dike, and a cofferdam is set downstream of the seepage channels and hazardous cracks. The dike is used to seal and reinforce the seepage channels by means of upstream sealing and backfilling and downstream dike body embankment.

[0006] Optionally, in the above-mentioned downstream sealing structure for seepage damage to a dike, the cofferdam is set at the outlet of the downstream seepage channel and the hazardous crack, and the cofferdam is constructed by filling and stacking sandbags.

[0007] Optionally, in the above-mentioned downstream sealing structure for seepage damage to a dike, the top width of the cofferdam is not less than 1m, and the slope of the upstream side of the cofferdam is 1:1 to 1:1.5, and the slope of the downstream side of the cofferdam is 1:2.

[0008] Optionally, in the above-mentioned downstream sealing structure for seepage damage to a dike, the height of the cofferdam is less than 5m, and the top height is level with or higher than the river water level.

[0009] Optionally, in the aforementioned downstream sealing structure for seepage damage to a dike, the upstream sealing backfill consists of a backfill body composed of large stones, sandbags, and other materials, as well as an upstream clay backfill body.

[0010] Optionally, in the above-mentioned downstream sealing structure for seepage damage to a dike, the downstream dike body backfill consists of clay mounds, medium-coarse sand filter layers, and stone slag backfill from upstream to downstream, all of which are formed by underwater dumping.

[0011] Optionally, in the above-mentioned downstream sealing structure for seepage damage to a dike, a number of fishing nets are set up downstream of the dike along the transverse direction of the water flow, and the two ends of the fishing nets are fixed to the original ground by wooden stakes.

[0012] This invention also proposes a method for sealing downstream seepage damage to dikes, which is accomplished using the aforementioned downstream sealing structure for dike seepage damage, and includes the following steps:

[0013] Step 1: Inspect the locations of seepage channels (2) and hazardous cracks (3) on the dam (1) to determine the hazardous range of seepage channels (2) and hazardous cracks (3) and the control line for the construction of the cofferdam (4);

[0014] Step 2: Further excavate in the relatively flat and shallow water section of the cofferdam (4) and its downstream section to increase the length of the downstream flow section of the seepage and stretch and fix multiple fishing nets along the transverse direction of the water flow at the downstream position of the cofferdam (4);

[0015] Step 3: Cofferdam (4) Construct a cofferdam using sandbags and taking advantage of the terrain to enclose the area affected by seepage;

[0016] Step 4: While constructing the cofferdam (4), the upstream river surface is filled with stone slag backfill material (603) and then backfilled upstream (5);

[0017] Step 5: After the cofferdam (4) is closed, the back of the cofferdam (4) is widened and thickened;

[0018] Step 6: While performing Step 5 or when the overall downstream flow velocity is significantly reduced, clay bags (601) are dumped at the outlet of the back seepage channel (2) and the hazardous crack (3), and the dumping volume is twice the designed dumping volume. The dumping is stopped when the leakage volume is significantly reduced by subjective judgment.

[0019] Step 7: Pour medium-coarse sand from the top of the dam (1) and manually fill it onto the back of the clay mound (601). The amount of medium-coarse sand is 1.5 times the design amount. Considering the small natural angle of repose underwater and the driving effect of the water flow, it is piled on the surface of the clay mound (601) to form a medium-coarse sand filter layer (602).

[0020] Step 8: During the implementation of Step 6 and Step 7, stop the upstream sealing and backfilling according to the actual site conditions (5);

[0021] Step 9: Use dump trucks to directly transport stone backfill material (603) to backfill the water pit formed by the cofferdam (4) with stone backfill material (603) until it is full and exceeds the upstream flood level or the predicted warning level. Then use a road roller to compact the stone backfill material (603).

[0022] Furthermore, in step three, the cofferdam (4) is first built from the dry land on both sides towards the middle. As the cofferdam (4) is built, the water level continues to rise. While raising the cofferdam (4) on both sides, it is gradually pushed towards the middle until it is closed. The raising of the cofferdam (4) on both sides is slightly slower than the rise in water level, but the depth of the flow on both sides is controlled within 50cm.

[0023] Furthermore, in step five, if the height of the formed cofferdam (4) cannot reach the water level on the upstream side, sandbags are manually thrown onto the back side to increase the size of the cofferdam (4).

[0024] In summary, the present invention has at least one of the following beneficial effects:

[0025] By using downstream cofferdams to raise the downstream water level, the seepage gradient of the seepage channel in the levee is reduced. As the downstream cofferdam is raised, the seepage gradient gradually decreases, the seepage damage gradually weakens, significantly improving the short-term safety of the levee and preventing the levee from being depleted due to seepage damage expansion in the short term. At the same time, it creates more favorable conditions for upstream filling and sealing.

[0026] The flat terrain downstream of the dike has a dispersing effect on the water flow. After the water flow is dispersed, the impact force of the water flow per unit width is significantly reduced, and the water depth is shallower. The underwater construction of the downstream cofferdam is less difficult and easier to implement.

[0027] By utilizing the high water level of the downstream cofferdam and the sealing effect of the upstream fill, the leakage volume and flow velocity are effectively controlled. The relatively gentle water flow within the downstream cofferdam is effectively sealed by layered fill, ensuring the safety of the dike during the flood season. Attached Figure Description

[0028] Figure 1 This is a plan view of the present invention;

[0029] Figure 2 This is a typical structural diagram of the present invention.

[0030] In the diagram: 1. Dam; 2. Seepage channel; 3. Harmful crack; 4. Cofferdam; 5. Upstream sealing and backfilling; 6. Downstream embankment backfilling; 601. Clay mound; 602. Medium-coarse sand filter layer; 603. Stone slag backfill. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1-2 The present invention will be described in further detail below.

[0032] Please refer to the attached diagram in the instruction manual. Figure 1-2 The present invention provides an embodiment of a downstream sealing structure for seepage damage to a dike, comprising a dike 1 located on the bank of the original river channel, wherein the terrain downstream of the original river channel is higher than the terrain of the riverbed. The dike 1 contains seepage channels 2 and hazardous cracks 3 formed by flood seepage damage. A cofferdam 4 is set at the downstream end of the seepage channels 2 and at the outlet of the downstream seepage channels 2 and hazardous cracks 3. The cofferdam 4 is constructed by filling and stacking sandbags. The top width of the cofferdam 4 is not less than 1m, and the slope of the upstream side of the cofferdam 4 is 1:1 to 1:1.5, and the slope of the downstream side of the cofferdam 4 is 1:2. The height of the cofferdam 4 is less than 5m, and the top height of the cofferdam 4 is level with or higher than the river water level.

[0033] Downstream of cofferdam 4, several fishing nets are set up along the transverse direction of the water flow to block cofferdam 4. The two ends of the fishing nets are fixed to the original river channel by wooden piles. Other similar lightweight and flexible nets with strong tensile strength can also be used. The fishing nets help reduce the possibility of cofferdam 4 being washed away by the water flow during the construction process, especially when cofferdam 4 is closed.

[0034] The dam 1 is used to seal and reinforce the seepage channel 2 by using upstream sealing and backfilling 5 and downstream dam body embankment 6. The upstream sealing and backfilling 5 consists of large stones, sandbags and other fill materials and upstream clay fill materials. The downstream dam body embankment 6 consists of clay bags 601, medium and coarse sand filter layer 602 and stone slag backfill material 603 from upstream to downstream, all of which are formed by underwater filling. The backfilling elevation of the stone slag backfill material 603 is higher than the river water level and the expected warning water level. After filling to above the water surface, it is compacted with a road roller.

[0035] Because the flow velocity in seepage channel 2 is relatively high, upstream sealing is difficult to achieve the desired sealing effect. At this time, it is necessary to construct a low cofferdam 4 downstream of the seepage channel, and reduce the seepage gradient and seepage volume in the dam 1 by raising the downstream water level. Then, the upstream sealing and backfilling 5 and the downstream dam body earthing 6 are used in combination to seal and reinforce the seepage channel of the dam body, thereby ensuring flood control safety.

[0036] The raw materials used in this scheme can be excavated nearby, and the raw materials can be substituted for each other. For example, sand bags can be used to replace clay bags 601, or clay bags 601 can be used to replace sand bags. There are no specific performance requirements for stone backfill material 603. Although the material adjustment will affect the sealing effect, it meets the requirements of short-term risk mitigation and avoids further expansion of risks.

[0037] In summary: by using sandbags and utilizing the terrain to construct cofferdam 4, the seepage hazard area is contained. When constructing cofferdam 4, it is first built from the dry areas on both sides towards the middle. As the cofferdam 4 is constructed, the water level continues to rise. While raising the cofferdam 4 on both sides, it is gradually pushed towards the middle until it is closed. After the cofferdam 4 is closed, the back of the cofferdam 4 is widened and thickened.

[0038] While constructing the cofferdam 4, upstream sealing and backfilling operations were carried out on the upstream river surface by dumping stone slag backfill material 603. At the same time, clay bags 601 were dumped at the outlet of the seepage channel 2 on the back side and the hazardous crack 3, and the dumping volume was twice the designed dumping volume. Medium and coarse sand was poured from the top of the embankment 1 and manually dumped onto the back of the clay bags 601, and the filling volume of medium and coarse sand was 1.5 times the designed filling volume, thus forming a medium and coarse sand filter layer 602.

[0039] Finally, dump trucks were used to directly transport stone backfill material 603 to backfill the water pit formed by the cofferdam 4 until it was full and exceeded the upstream flood level or the predicted warning level. Then, a road roller was used to compact the stone backfill material 603.

[0040] To better demonstrate a downstream sealing structure for seepage damage to a dike, this embodiment proposes a method for downstream sealing of seepage damage to a dike, comprising the following steps:

[0041] Step 1: First, conduct intensive patrols of the areas where seepage channels 2 and hazardous cracks 3 are distributed in the dam 1, so as to determine the scope of the hazards of seepage channels 2 and hazardous cracks 3 and the control line for the construction of the cofferdam 4.

[0042] Step 2: Then, further excavate the relatively flat and shallow water section downstream of cofferdam 4 to increase the length of the downstream flow section for dispersing the water flow. At the same time, stretch multiple fishing nets along the transverse direction of the water flow downstream of cofferdam 4 and fix them with wooden stakes at both ends.

[0043] Step 3: Cofferdam 4 is constructed using sandbags and the terrain to contain the seepage hazard. When constructing cofferdam 4, it is first built from the dry areas on both sides towards the middle. As cofferdam 4 is constructed, the water level rises continuously. While raising the cofferdams on both sides, it is gradually pushed towards the middle until it is closed. In order to reduce the difficulty of closing cofferdam 4, the raising of the cofferdams on both sides is slightly slower than the rise in water level, but the depth of the flow on both sides is controlled within 50cm to ensure the safety of personnel.

[0044] Step 4: While constructing the cofferdam 4, backfill the upstream river surface with stone rubble backfill material 603 and backfill the upstream area 5;

[0045] Step 5: After the cofferdam 4 is closed, the back of the cofferdam 4 is widened and thickened. If the cofferdam 4 formed at this time cannot reach the water level on the upstream side due to the limitation of the embankment height, there may still be a situation of overflow at the top. When this happens, the overflowing water is generally shallow. Sandbags can be manually thrown on the back to increase the size of the cofferdam 4 and ensure its stability.

[0046] Step Six: While performing Step Five, or when the overall downstream flow velocity is significantly reduced, clay bags 601 are dumped at the outlet of the back seepage channel 2 and the hazardous crack 3. The dumping volume is twice the designed dumping volume. The dumping is stopped when the leakage volume is significantly reduced by subjective judgment.

[0047] Step 7: Pour medium-coarse sand from the top of the dam 1 and manually fill it onto the back of the clay mound 601. The amount of medium-coarse sand is 1.5 times the designed amount. Considering the small natural angle of repose underwater and the driving effect of the water flow, the sand is deposited on the surface of the clay mound (601) to form a medium-coarse sand filter layer (602).

[0048] Step 8: During the implementation of steps 6 and 7, stop upstream sealing and backfilling 5 based on the actual site conditions;

[0049] Step 9: Finally, dump trucks are used to directly transport stone backfill material 603 to backfill the water pit formed by the cofferdam 4 until it is full and exceeds the upstream flood level or the predicted warning level. Then, a road roller is used to compact the stone backfill material 603.

[0050] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for sealing downstream seepage damage to a dike, comprising a downstream sealing structure for seepage damage to a dike, the sealing structure comprising a dike (1) located on the bank of the original river channel, wherein the dike (1) contains seepage channels (2) and harmful cracks (3) formed by flood seepage damage, characterized in that: A cofferdam (4) is set up downstream of the seepage channel (2) and the hazardous crack (3). The dam (1) is used to seal and reinforce the seepage channel (2) by means of upstream sealing and backfilling (5) and downstream dam body reinforcement (6). The sealing method includes the following steps: Step 1: Inspect the locations of seepage channels (2) and hazardous cracks (3) on the dam (1) to determine the hazardous range of seepage channels (2) and hazardous cracks (3) and the control line for the construction of the cofferdam (4); Step 2: Further excavate in the relatively flat and shallow water section of the cofferdam (4) and its downstream section to increase the length of the downstream flow section of the seepage and stretch and fix multiple fishing nets along the transverse direction of the water flow at the downstream position of the cofferdam (4); Step 3: Cofferdam (4) Construct a cofferdam using sandbags and taking advantage of the terrain to enclose the area affected by seepage; Step 4: While constructing the cofferdam (4), the upstream river surface is filled with stone slag backfill material (603) and then backfilled upstream (5); Step 5: After the cofferdam (4) is closed, the back of the cofferdam (4) is widened and thickened; Step 6: While performing Step 5 or when the overall downstream flow velocity is significantly reduced, clay bags (601) are dumped at the outlet of the back seepage channel (2) and the hazardous crack (3), and the dumping volume is twice the designed dumping volume. The dumping is stopped when the leakage volume is significantly reduced by subjective judgment. Step 7: Pour medium-coarse sand from the top of the dam (1) and manually fill it onto the back of the clay mound (601). The amount of medium-coarse sand is 1.5 times the design amount. Considering the small natural angle of repose underwater and the driving effect of the water flow, it is piled on the surface of the clay mound (601) to form a medium-coarse sand filter layer (602). Step 8: During the implementation of Step 6 and Step 7, stop the upstream sealing and backfilling according to the actual site conditions (5); Step 9: Use dump trucks to directly transport stone backfill material (603) to backfill the water pit formed by the cofferdam (4) with stone backfill material (603) until it is full and exceeds the upstream flood level or the predicted warning level. Then use a road roller to compact the stone backfill material (603).

2. The method for sealing downstream seepage damage to a dike according to claim 1, characterized in that: The cofferdam (4) is located at the outlet of the downstream seepage channel (2) and the hazardous crack (3), and the cofferdam (4) is constructed by filling and stacking sandbags.

3. The method for sealing downstream seepage damage to a dike according to claim 2, characterized in that: The top width of the cofferdam (4) is not less than 1m, and the slope of the upstream side of the cofferdam (4) is 1:1 ~ 1:1.5, and the slope of the downstream side of the cofferdam (4) is 1:

2.

4. The method for sealing downstream seepage damage to a dike according to claim 3, characterized in that: The cofferdam (4) is less than 5m high, and its top is level with or higher than the river water level.

5. The method for sealing downstream seepage damage to a dike according to claim 1, characterized in that: The upstream sealing and backfilling (5) consists of large stones, sandbag filling and upstream clay filling.

6. The method for sealing downstream seepage damage to a dike according to claim 1, characterized in that: The downstream embankment backfill (6) consists of clay mounds (601), medium-coarse sand filter layer (602), and stone slag backfill (603) from upstream to downstream, all of which are formed by underwater dumping.

7. The method for sealing downstream seepage damage to a dike according to claim 1, characterized in that: Downstream of the cofferdam (4), several fishing nets are set up along the transverse direction of the water flow to block the cofferdam (4). The two ends of the fishing nets are fixed to the original ground by wooden stakes.

8. The method for sealing downstream seepage damage to a dike according to claim 1, characterized in that: In step three, the cofferdam (4) is first built from the dry land on both sides towards the middle. As the cofferdam (4) is built, the water level continues to rise. While raising the cofferdam (4) on both sides, it is gradually pushed towards the middle until it is closed. The raising of the cofferdam (4) on both sides is slightly slower than the rise in water level, but the depth of the flow on both sides is controlled within 50cm.

9. The method for sealing downstream seepage damage to a dike according to claim 1, characterized in that: In step five, if the height of the formed cofferdam (4) cannot reach the water level on the upstream side, sandbags are manually thrown onto the back side to increase the size of the cofferdam (4).

Images