Underground water drainage system for riverway protection construction

Abstract

The utility model discloses a riverway protection construction is with groundwater drainage system, include: cofferdam, diversion pipe, open ditch, precipitation well and blind ditch, the cofferdam is located the upstream of construction area, and cofferdam straddles riverway, diversion pipe passes through cofferdam and connects the upstream of construction area and downstream of construction area, open ditch is set up in the intermediate position of construction area along the water flow direction, precipitation well sets up in the pointy spring point position of construction area, blind ditch sets up in the sheety groundwater spring point position and side slope seepage position of construction area, and blind ditch is linked together with open ditch, the utility model discloses cofferdam intercepts and through diversion pipe diversion riverway water, open ditch leads and discharges the remaining open water in riverway and the underground water that emerges, then utilizes precipitation well and point control and reduce groundwater and pointy spring point, for sheety groundwater spring point and side slope seepage increase blind ditch drainage, thereby realizes fast drainage.

Description

Technical Field

[0001] This utility model belongs to the field of river dewatering technology, specifically relating to a groundwater dewatering system for river protection construction. Background Technology

[0002] River protection is a common practice for reinforcing river channels and reducing flood damage. However, for rivers with perennial flow and abundant groundwater, river protection construction faces a series of challenges, including the presence of surface water and groundwater. For example, abundant groundwater after dredging and excavation continuously seeps into the foundation pit, making it impossible to carry out normal subgrade, masonry, or concrete pouring operations, thus affecting construction. Moreover, due to the abundant groundwater in the riverbed construction area, the riverbed soil gradually turns into silt after excavation, and the silt becomes softer over time, requiring immediate treatment and the creation of suitable construction conditions. The conventional approach is to use wellpoint dewatering measures over a large area, with dewatering wells densely arranged. In order to achieve the desired precipitation effect, most construction sites have soft soil, making it impossible for personnel and equipment to deploy well points over a large area. For example, frequent entry and exit of large equipment will disturb the mud and exacerbate the construction difficulties. Wells can only be deployed in a small number of specific point spring locations to achieve the maximum effect. In addition, the water content of the silt at the bottom of the river is close to saturation, and the soil permeability of the riverbed is poor, limiting the precipitation area of ​​the wells. Furthermore, the sump pit is constantly collapsing and expanding under the erosion and impact of underground seepage, leading to soil erosion. The high groundwater and soil erosion issues during construction require immediate treatment, creating a pressing issue of construction schedule and urgency, necessitating immediate dewatering. Utility Model Content

[0003] To address the aforementioned issues, this utility model proposes a groundwater drainage system for river protection construction. A small number of dewatering wells are arranged at specific point-like spring locations to achieve maximum effect. A series of combined measures, including open drainage ditches, blind drainage ditches, diversion pipes, and sump pits, are added. Geotextile is laid at the bottom of the dewatering wells and the edge of the sump pits to reduce soil erosion.

[0004] This utility model discloses a groundwater drainage system for river protection construction. The system comprises a construction area within the river channel, including: a cofferdam located upstream of the construction area and spanning the river channel, which, after completion, becomes a construction road connecting the left and right banks of the river; a diversion pipe passing through the cofferdam to divert river water impounded upstream of the construction area to the downstream river channel; an open ditch constructed along the water flow direction in the middle of the construction area to facilitate zoned construction on both sides; dewatering wells located at point spring locations within the construction area; and blind drains located at patchy groundwater spring locations and slope seepage points within the construction area, connected to the open ditch.

[0005] The inlet of the diversion pipe is pre-embedded on the water accumulation side of the cofferdam.

[0006] At the downstream end of the open ditch, a sump pit connected to the open ditch is set up. The bottom of the sump pit is protected with geotextile, and a pumping and drainage system is installed in the sump pit. The dewatering well in the sump pit is a dewatering well that is set up and permanently reserved to lower the groundwater level in the sump pit during the final stage of construction.

[0007] The dewatering wells are connected to the downstream of the construction area or to a sump via water pumps and pipes.

[0008] The dewatering well is a sand-free pipe dewatering well, and the bottom of the sand-free pipe dewatering well is wrapped with geotextile.

[0009] The blind drains are set along the riverbed slope and distributed on both sides of the open ditch. The blind drains are set along the naturally formed underground drainage channels and eventually converge and connect to the open ditch.

[0010] The blind drain is filled with gravel wrapped in geotextile to form a water passage, and a soil layer is laid on top of the geotextile.

[0011] The beneficial effects of this utility model are that it adopts a cofferdam to intercept the river and diverts the river water through a diversion pipe, drains the remaining open water and the emerging groundwater in the river through an open ditch, and then uses dewatering wells to control the groundwater and point springs at each point. For patchy groundwater springs and slope seepage, blind drains are added to achieve rapid dewatering and drainage to meet the conditions for construction. Attached Figure Description

[0012] Figure 1 This is a top view schematic diagram of the groundwater drainage system for river protection construction according to this utility model.

[0013] Figure 2 This is a schematic diagram of the blind drain of this utility model.

[0014] Figure 3 This is a schematic diagram of the structure of the precipitation well of this utility model.

[0015] Figure 4 This is a schematic diagram of the structure of the water collection pit without dewatering well during the construction of this utility model.

[0016] Figure 5 This is a schematic diagram of the structure of the water collection pit with dewatering wells in the final stage of the construction of this utility model.

[0017] Figure label:

[0018] 1. Cofferdam; 2. Open ditch; 3. Diversion pipe; 4. Sump; 5. Blind ditch; 6. Dewatering well; 7. Geotextile; 8. Crushed stone; 9. River channel; 10. Connecting plate; 11. Steel wire. Detailed Implementation

[0019] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] like Figures 1-5 As shown, the groundwater drainage system for river protection construction of this utility model includes: a cofferdam 1, a diversion pipe 3, an open ditch 2, a dewatering well 6, and a blind ditch 5. The cofferdam 1 is located upstream of the construction area and spans the river channel 9. After the cofferdam is filled, it naturally forms a construction road connecting the left and right banks of the river channel. The cofferdam 1 is used to intercept the upstream water of the river channel 9, forming a barrier lake. The construction area is located between the cofferdam 1 and the downstream river channel of the river channel 9.

[0021] A diversion pipe 3 is pre-embedded in the cofferdam 1 to naturally divert the river water upstream of the cofferdam 1 to the downstream of the construction area, thereby eliminating the impact of the river water on the construction area.

[0022] The diversion pipe 3 passes through the cofferdam 1 and connects the upstream and downstream of the construction area; specifically, the inlet of the diversion pipe 3 is pre-buried on the water accumulation side of the cofferdam 1, and diverts the river water upstream of the cofferdam 1 to the river channel downstream of the construction area.

[0023] Open ditch 2 is set in the middle of the construction area along the direction of water flow, which facilitates construction on both sides of the open ditch. Open ditch 2 is used to drain the remaining open water in the river and the emerging groundwater.

[0024] Dewatering wells 6 are mainly located at point springs in the construction area. There are multiple dewatering wells 6. These are sand-free dewatering wells, which collect and pump groundwater to lower the groundwater level without causing soil erosion. The wells 6 use pumping facilities to drain the collected groundwater into the downstream river channel of the construction area. The bottom of the wells is wrapped with geotextile to prevent soil erosion. The pumping facilities consist of water pumps and pipes.

[0025] Sand-free pipe dewatering wells are dewatering engineering facilities that use sand-free concrete pipes as filter structures. They are mainly used to lower the groundwater level, drain groundwater, or treat building foundation pit dewatering. Sand-free pipes are made of concrete that does not contain fine sand, and their main components are gravel, cement, and a small amount of pebbles (3-5mm). They have high porosity (about 20%-25%) and are permeable.

[0026] The bottom of the sandless dewatering well is wrapped with geotextile to prevent soil from entering and being lost.

[0027] The length of one sand-free pipe in a sand-free dewatering well is 1m. One sand-free pipe is not deep enough and the drainage effect is limited, so two sand-free pipes need to be installed. The two sand-free pipes need to be connected as a whole to avoid misalignment, damage, or tilting when the pipes are installed. Specifically, the sand-free pipes are connected by a connecting plate 10 and fixed with iron wire 11. The connecting plate 10 can be made of bamboo or wood.

[0028] Blind drain 5 is located at the points where patchy groundwater springs emerge and at the locations where seepage occurs on the slope within the construction area, and it is connected to open ditch 2. Specifically, blind drain 5 is positioned along naturally formed underground drainage channels, starting from the high groundwater seepage point on the riverbed slope and ultimately converging with open ditch 2.

[0029] The blind drain 5 is filled with gravel 8 wrapped with geotextile 7 to form a hidden water passage, and a soil layer is laid on top of the geotextile 7 to facilitate the construction of the upper protection of the blind drain without affecting the drainage function of the blind drain.

[0030] Blind drain 5 is installed at the point where the groundwater springs are located for drainage. Blind drain 5 can adapt to the original groundwater flow path to form a permanent drainage channel, and the upper part of blind drain 5 does not affect normal construction.

[0031] A sump pit 4 is installed at the downstream end of open ditch 2. The sump pit 4 is connected to open ditch 2 and is protected with geotextile 7 to reduce soil erosion and prevent pit wall collapse. At the same time, the water in the sump pit 4 can be directly pumped to the downstream of the river to lower the groundwater level in the construction area. Open ditch 2 is used to drain the remaining open water and the emerging groundwater in the river.

[0032] First, an open ditch 2 was excavated on site to divert and drain the open water. After measures such as diversion by the open ditch 2 and water collection and pumping by the sump pit 4 were adopted, the open water was reduced. However, the edge of the sump pit 4 gradually collapsed under the seepage of groundwater, and the water and soil in the riverbed were eroded. Therefore, the sump pit was protected with geotextile and combined with well point dewatering, sand-free pipe dewatering wells 6 were gradually laid in areas where conditions permit to reduce water and soil erosion.

[0033] The top of the dewatering well at the location of the point spring in the construction area is level with or slightly higher than the ground level of the construction area.

[0034] During the final stage of construction, dewatering wells are installed in the sump during the filling and revetment process to lower the groundwater level and make it suitable for construction. The top of the dewatering wells in the sump is slightly higher than the top of the sump. That is, there are no dewatering wells in the sump during the construction period; they are only installed in the final stage of construction.

[0035] In use, this invention involves first constructing a cofferdam 1 upstream of the construction area, and simultaneously pre-burying a diversion pipe 3 to naturally guide the upstream river water to the downstream of the construction area. An open ditch 2 is excavated in the middle of the construction area at the riverbed to drain surface water. Dewatering wells 6 are installed at point spring locations and at the sump pit 4, while blind drains 5 are installed at the patchy groundwater spring locations. Water from the blind drains 5 eventually converges into the open ditch 2 and flows to the sump pit 4, where it is then pumped downstream. Water from the dewatering wells 6 is pumped and piped into the downstream river channel. Finally, the open ditch 2 is filled, and a reserved dewatering well 6 is installed within the sump pit 4 to drain water and meet the final construction conditions in the sump pit area. The dewatering wells 6 are permanently retained to reduce groundwater pressure.

[0036] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A groundwater drainage system for river protection construction, wherein a construction area is arranged within the river channel, characterized in that, include: The cofferdam is located upstream of the construction area and spans the river. After the cofferdam is filled, it becomes a construction road connecting the left and right banks of the river. A diversion pipe passes through the cofferdam and diverts the river water impounded by the cofferdam upstream of the construction area to the river downstream of the construction area. An open ditch is constructed in the middle of the construction area along the direction of water flow, which facilitates construction on both sides of the open ditch. Dewatering wells are located at the points of springs in the construction area; Blind drains are installed at the locations of surface groundwater springs and seepage points on the slopes within the construction area, and are connected to open drains.

2. The groundwater drainage system for river protection construction according to claim 1, characterized in that, The inlet of the diversion pipe is pre-embedded on the water accumulation side of the cofferdam.

3. The groundwater drainage system for river protection construction according to claim 1, characterized in that, A sump pit connected to the open ditch is set at the downstream end of the open ditch. The bottom of the sump pit is protected with geotextile, and drainage facilities are installed in the sump pit.

4. The groundwater drainage system for river protection construction according to claim 3, characterized in that, The dewatering wells are connected to the downstream of the construction area or to a sump via water pumps and pipes.

5. The groundwater drainage system for river protection construction according to claim 1, 3, or 4, characterized in that, The dewatering well is a sand-free pipe dewatering well, and the bottom of the sand-free pipe dewatering well is wrapped with geotextile.

6. The groundwater drainage system for river protection construction according to claim 1, characterized in that, The blind drains are set along the riverbed slope and distributed on both sides of the open ditch. The blind drains are set along the naturally formed underground drainage channels and eventually converge and connect to the open ditch.

7. The groundwater drainage system for river protection construction according to claim 6, characterized in that, The blind drain is filled with gravel wrapped in geotextile to form a water passage, and a soil layer is laid on top of the geotextile.

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