A foundation drainage system of a large sand discharge funnel in a deep overburden area

Abstract

The utility model discloses a kind of foundation drainage systems of large-scale sand discharge funnel in deep overburden area, is divided into soil and stone inverse filtration area, drainage blind ditch area, bottom catchment area and drainage pipeline area;Bottom catchment area is arranged in the bottom of the center of sand discharge funnel bottom plate below, set around bottom vertical shaft outer side a circle, bottom catchment area outside, bottom uses concrete cushion layer to close, inside backfill broken stone;Soil and stone inverse filtration area and drainage blind ditch area are arranged in the bottom plate below of sand discharge funnel, and the joint part with the bottom plate of sand discharge funnel is all set sandless concrete layer, and soil and stone inverse filtration area is provided with soil and stone inverse filtration layer below sandless concrete layer, and broken stone is backfilled in drainage blind ditch in the sandless concrete layer below of drainage blind ditch area, and a plurality of drainage blind ditches converge in the bottom catchment area of the bottom of sand discharge funnel;Drainage pipeline area uses bottom catchment area as starting point, and drainage pipeline is arranged along sand discharge corridor both sides. Arrangement is reasonable, economical and practical, ensure the safety of funnel structure and foundation, also save a lot of engineering quantity.

Description

Technical Field

[0001] This utility model relates to the technical field of sand-drainage funnels in water conservancy and hydropower engineering, and in particular to a basic drainage system for a large sand-drainage funnel in areas with deep overburden. Background Technology

[0002] Desand discharge funnels are a commonly used, economical, and highly effective hydraulic structure in run-of-river power stations. Because they are typically located in unpressurized open channel sections, the terrain at most of these locations is relatively flat, resulting in most funnels being placed in areas with deep overburden. Constructing desand discharge funnels in overburden areas presents key challenges, particularly in addressing foundation bearing capacity, operational drainage, and foundation stability beneath the slab. This is especially critical in areas with deep overburden, where the situation is even more challenging when deploying ultra-large desand discharge funnels. In existing projects, uneven settlement of the funnel bottom slab is frequently observed after years of operation. Since the project is already operational, repairs require significant time and investment; if not addressed promptly, the settlement will worsen, leading to cracks in the sealing gaskets, leakage into the foundation, and gradual deterioration of the foundation's particle size distribution, ultimately causing further damage and greater safety hazards and economic losses. Utility Model Content

[0003] The purpose of this invention is to provide a basic drainage system for large sand-discharging funnels in areas with deep overburden, thereby solving the aforementioned problems in arranging large sand-discharging funnels in areas with deep overburden.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a basic drainage system for a large sand-discharging funnel in a region with a thick overburden layer, the large sand-discharging funnel including a sand-discharging funnel bottom plate, a bottom vertical shaft, and a sand-discharging corridor, the basic drainage system being divided into a soil and rock reverse filter zone, a drainage blind ditch zone, a bottom water collection zone, and a drainage pipe zone. The bottom water collection area is located below the center bottom of the sand discharge funnel bottom plate, and is set around the outside of the bottom vertical shaft. The outside and bottom of the bottom water collection area are sealed with a concrete cushion layer, and the inside is backfilled with crushed stone. Both the soil-rock filter zone and the drainage blind ditch zone are located below the bottom plate of the sand discharge funnel. A no-fines concrete layer is set at the junction with the bottom plate of the sand discharge funnel. A soil-rock filter layer is set below the no-fines concrete layer in the soil-rock filter zone. The drainage blind ditch set below the no-fines concrete layer in the drainage blind ditch zone is backfilled with gravel. Multiple drainage blind ditches converge at the bottom water collection area at the bottom of the sand discharge funnel. In the drainage pipeline area, drainage pipelines are arranged along both sides of the sand discharge corridor, starting from the bottom water catchment area.

[0005] Furthermore, the soil-rock filter zone is arranged between the original foundation and the bottom plate of the sand discharge funnel, and the coverage area includes the projection range of the sand discharge funnel and the main auxiliary structures. It consists of a sand-free concrete layer and a soil-rock filter layer. The sand-free concrete layer is arranged in connection with the bottom plate structure of the sand discharge funnel, and the soil-rock filter layer is arranged below the sand-free concrete layer and in connection with the original foundation. The soil-rock filter layer is required to have a continuous particle size distribution.

[0006] Furthermore, the drainage blind ditch area is arranged below the bottom plate structure of the sand discharge funnel and is spatially arranged in a divergent manner. The drainage blind ditch is arranged below the no-fines concrete layer and has a certain slope from the outside to the inside. All drainage blind ditches converge into the bottom water collection area. The drainage blind ditch adopts a structure of C15 plain concrete with crushed stone backfill.

[0007] Furthermore, the bottom water collection area has a wheel-shaped structure that is larger at the top and smaller at the bottom, and the bottom water collection area is connected to the drainage pipe area.

[0008] Furthermore, the drainage pipe area is arranged on both sides of the sand-drainage corridor, with the same slope as the sand-drainage corridor, and adopts a concrete pipe structure; the drainage pipe area is connected to the bottom water collection area, and the water collected in the sand-drainage blind ditch is discharged downstream along the drainage pipe.

[0009] The beneficial effects of this utility model are as follows: This utility model uses a combination structure of graded soil and stone, no-fines concrete, drainage blind ditch, crushed stone and concrete to treat the foundation of the super-large sand discharge funnel on the thick overburden layer. It meets the bearing capacity requirements of the sand discharge funnel foundation under this type of geological condition. The layout is reasonable, economical and practical, and ensures the safe operation of the sand discharge funnel structure foundation. It can be widely used in the layout of large sand discharge funnels on the thick overburden layer. Attached Figure Description

[0010] Figure 1 This is a plan view of the present invention.

[0011] Figure 2 yes Figure 1 A schematic diagram of the cross section of AA.

[0012] Figure 3 yes Figure 1 A cross-sectional view of BB.

[0013] Figure 4 This is a cross-sectional schematic diagram of the drainage pipe of this utility model.

[0014] Figure 5 This is a schematic cross-sectional view of the bottom water collection area of ​​this utility model.

[0015] In the diagram: 1---Soil and rock filter layer; 2---No-fines concrete layer; 3---Gravel; 4---Drainage blind ditch; 5---Bottom catchment area; 6---Drainage pipe; 7---Bottom plate of sand discharge funnel; 8---Bottom shaft; 9---Sand discharge gallery; The arrows indicate the direction of drainage water flow. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0017] In the description of this utility model, it should be noted that the terms "upper", "middle", "lower", "inner", "outer", "both sides", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0018] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0019] like Figure 1 As shown in Figure 5, the basic drainage system of the large sand-discharging funnel in the thick overburden area of ​​this utility model includes a sand-discharging funnel bottom plate 7, a bottom vertical shaft 8, and a sand-discharging corridor 9. The basic drainage system is divided into a soil and rock reverse filter area, a drainage blind ditch area, a bottom water collection area, and a drainage pipe area. The bottom water collection area 5 is located below the center bottom of the sand discharge funnel bottom plate 7, and is set around the outside of the bottom vertical shaft 8. The outside and bottom of the bottom water collection area are sealed with a concrete pad layer, and the inside is backfilled with crushed stone. Both the soil and rock filter zone and the drainage blind ditch zone are arranged below the bottom plate 7 of the sand discharge funnel. The part that connects with the bottom plate 7 of the sand discharge funnel is provided with a sand-free concrete layer 2. The soil and rock filter layer 1 is set below the sand-free concrete layer 2 of the soil and rock filter zone. The drainage blind ditch 4 set below the sand-free concrete layer 2 of the drainage blind ditch zone is backfilled with crushed stone 3. Multiple drainage blind ditches 4 converge at the bottom water collection area 5 at the bottom of the sand discharge funnel. In the drainage pipe area, drainage pipes 6 are arranged along both sides of the sand discharge corridor 9, starting from the bottom water catchment area 5.

[0020] Furthermore, the soil-rock filter zone is arranged between the original foundation and the bottom plate of the sand discharge funnel, and the coverage area includes the projection range of the sand discharge funnel and the main auxiliary structures. It consists of a sand-free concrete layer 2 and a soil-rock filter layer 1. The sand-free concrete layer is arranged in connection with the bottom plate structure of the sand discharge funnel, and the soil-rock filter layer is arranged below the sand-free concrete layer and in connection with the original foundation. The soil-rock filter layer is required to have a continuous particle size distribution.

[0021] Furthermore, the drainage blind ditch area is arranged below the bottom plate structure of the sand discharge funnel and is arranged in a radiating pattern in space. The drainage blind ditch 4 is arranged below the sand-free concrete layer and has a certain slope from the outside to the inside. All drainage blind ditches 4 converge into the bottom water collection area 5. The drainage blind ditch adopts a structure of C15 plain concrete with crushed stone backfill.

[0022] Furthermore, the bottom water collection area 5 is a wheel-shaped structure that is larger at the top and smaller at the bottom, and the bottom water collection area is connected to the drainage pipe area.

[0023] Furthermore, the drainage pipe area is arranged on both sides of the sand-drainage corridor 9, with the same slope as the sand-drainage corridor, and adopts a concrete pipe structure; the drainage pipe area is connected to the bottom water collection area, and the water collected in the sand-drainage blind ditch is discharged downstream along the drainage pipe.

[0024] Specifically, the gravel layer 3 and drainage blind drains 4 are arranged close to the no-fines concrete layer 2 below the bottom plate structure 7 of the sand-discharging funnel. All blind drains converge at the bottom catchment area 5 at the bottom of the sand-discharging funnel bottom plate 7. Drainage pipes 6 are arranged along both sides of the sand-discharging corridor from the starting point of the bottom catchment area 5. A soil-rock filter area is arranged in the non-blind drain area. The soil-rock filter area is located on the original foundation and consists of a soil-rock filter layer 1 and a no-fines concrete layer 2. The drainage blind drain area consists of the no-fines concrete layer 2, gravel layer 3, and drainage blind drains 4. The drainage blind drains are arranged below the sand-discharging funnel structure in a radiating pattern, with a certain slope from the outside in. All drainage blind drains converge into the bottom catchment area 5. The drainage blind drains 4 adopt a structure of C15 plain concrete with gravel backfill. The bottom catchment area 5 is a platform shape, wider at the top and narrower at the bottom. The outer side and bottom of the catchment area are enclosed by a concrete structure, while the inner bottom is backfilled with gravel. The bottom catchment area connects to the drainage pipes 6. Drainage pipe 6 is arranged on both sides of the sand-drainage corridor, with the same slope as the sand-drainage corridor, and adopts a concrete pipe structure; drainage pipe 6 connects to the bottom drainage area, and discharges the water collected in the drainage blind ditch 4 into the downstream through the drainage pipe.

[0025] The soil-rock reverse filtration zone is arranged between the original foundation and the bottom plate of the sand discharge funnel, covering the projection range of the sand discharge funnel and the main auxiliary structures. It consists of a sand-free concrete layer and a reverse filter layer. The sand-free concrete layer is connected to the bottom plate structure of the sand discharge funnel, and the reverse filter layer is arranged below the sand-free concrete layer and connected to the original foundation. The thickness of the sand-free concrete structure is 0.15m~0.3m, and the thickness of the reverse filter layer is 0.5m~1m. The reverse filter layer is required to have a continuous particle size distribution.

[0026] The drainage blind ditch areas are arranged below the bottom plate structure of the sand discharge funnel in a radiating spatial arrangement. The blind ditches are arranged below the no-fines concrete and have a certain slope from the outside to the inside. All blind ditches converge into the bottom water collection area. The thickness of the no-fines concrete structure is 0.15m to 0.3m. The drainage blind ditches adopt a structure of 0.15m thick C15 plain concrete filled with crushed stone.

[0027] The bottom catchment area is shaped like a wheel, wider at the top and narrower at the bottom. The outer side and bottom of the catchment area are enclosed by a 0.15m thick concrete structure, and the inside is backfilled with gravel. The bottom catchment area is connected to the drainage pipe.

[0028] This utility model has a reasonable layout and complete functions, ensuring the safe operation of the sand discharge funnel structure and foundation, and saving engineering work and investment.

[0029] The following example, using a hydropower station project that adopted the technical solution of this utility model, is further illustrated with reference to the accompanying drawings: A certain hydropower station project features a sediment discharge funnel with a net diameter of 70 meters, making it the largest single sediment discharge funnel in China. This funnel is situated on a broad, flat, and deep overburden layer, connected upstream and downstream to an unpressurized culvert and open channel. Due to the low bearing capacity of the overburden foundation in this area, it cannot meet the bearing capacity requirements for the normal operation of the sediment discharge funnel, necessitating foundation treatment. A common foundation treatment method in engineering projects is to replace the concrete with a certain thickness. While this method can temporarily solve the bearing capacity problem, the deep foundation lacks rigidity due to the structure's location on the deep overburden layer, and a rigid concrete cushion cannot accommodate the deformation coordination of a flexible foundation under long-term operation. Increasing the replacement area and depth would drastically increase the workload, construction difficulty, and project investment. Under the existing conditions, to meet the foundation bearing capacity requirements of the sediment discharge funnel while simultaneously considering the deformation coordination between the deep overburden foundation and the structure, ensuring the long-term safe and stable operation of the sediment discharge funnel structure and foundation, a combination of foundation treatment and drainage methods can be considered to solve these problems. This project adopts the large sand-drainage funnel foundation drainage system of this utility model, suitable for areas with deep overburden. The drainage blind ditch 3 has a net size of 0.4m × 0.4m (width × height), with a sidewall base plate thickness of 0.05m. It adopts a structure of concrete backfilled with crushed stone, arranged close to the bottom of the no-fines concrete layer 2, collecting water from all sides towards the bottom catchment area 4. The thickness of the no-fines concrete layer 2 is 0.15m. Below the no-fines concrete layer 2, in the area not covered by the drainage blind ditch, a soil-rock filter zone 1 is arranged. The soil-rock filter zone 1 has a thickness of 0.5m, with continuous particle size distribution, and is made from improved original foundation soil and rock. Specific parameters are: maximum particle size ≤ 150mm, particle content < 5mm ≥ 15% and ≤ 25%, particle content < 0.075mm ≤ (3~5)%, compacted porosity n ≤ 21%, and design dry density ≥ 2.32g / cm³. 3 The bottom catchment area 4 is located at the intersection of the drainage blind ditch 3. It is a platform-shaped structure that is wider at the top and narrower at the bottom. The outer side and bottom are enclosed with concrete structures, and the interior is backfilled with gravel. It connects to the drainage pipe 5. The drainage pipe 5 is arranged on both sides of the sand discharge corridor, with the same slope as the sand discharge corridor. It adopts a precast concrete pipe structure with an inner diameter of 0.5m.

[0030] This utility model adopts a foundation drainage system with a large sand-draining funnel in areas with deep overburden. It comprehensively considers the boundary conditions of the foundation with deep overburden, and solves the problems of foundation bearing capacity and drainage function. The layout is reasonable, economical and practical.

[0031] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present utility model, and these improvements should also be considered within the protection scope of the present utility model.

Claims

1. A foundation drainage system for a large sand-discharging funnel in a region with a thick overburden layer, the large sand-discharging funnel comprising a bottom plate (7), a bottom shaft (8), and a sand-discharging corridor (9), characterized in that, The basic drainage system is divided into a soil-rock filter area, a drainage blind ditch area, a bottom catchment area, and a drainage pipe area; The bottom water collection area (5) is located below the center bottom of the bottom plate (7) of the sand discharge funnel, and is set around the outside of the bottom vertical shaft (8). The outside and bottom of the bottom water collection area are sealed with concrete cushion layer, and the inside is backfilled with crushed stone. The soil-rock filter zone and the drainage blind ditch zone are both arranged below the bottom plate (7) of the sand discharge funnel. The sand-free concrete layer (2) is set at the junction with the bottom plate (7) of the sand discharge funnel. The soil-rock filter layer (1) is set below the sand-free concrete layer (2) of the soil-rock filter zone. The drainage blind ditch (4) set below the sand-free concrete layer (2) of the drainage blind ditch zone is backfilled with crushed stone (3). Multiple drainage blind ditches (4) converge at the bottom water collection area (5) at the bottom of the sand discharge funnel. In the drainage pipeline area, drainage pipelines (6) are arranged along both sides of the sand discharge corridor (9), starting from the bottom water catchment area (5).

2. The foundation drainage system for large sand-draining funnels in areas with deep overburden as described in claim 1, characterized in that, The soil and rock filter zone is arranged between the original foundation and the bottom plate of the sand discharge funnel. The coverage area includes the projection range of the sand discharge funnel and the main auxiliary structures. It consists of a sand-free concrete layer (2) and a soil and rock filter layer (1). The sand-free concrete layer is arranged in connection with the bottom plate structure of the sand discharge funnel. The soil and rock filter layer is arranged below the sand-free concrete layer and is connected to the original foundation. The soil and rock filter layer is required to have continuous particle size distribution.

3. The foundation drainage system for large sand-draining funnels in areas with deep overburden as described in claim 1, characterized in that, The drainage blind ditch area is arranged below the bottom plate structure of the sand discharge funnel and is arranged in a radiating pattern in space. The drainage blind ditch (4) is arranged below the sand-free concrete layer and has a certain slope from the outside to the inside. All drainage blind ditches (4) converge into the bottom water collection area (5). The drainage blind ditch adopts a structure of C15 plain concrete with crushed stone backfill.

4. The foundation drainage system for large sand-draining funnels in areas with deep overburden as described in claim 1, characterized in that, The bottom water collection area (5) is a wheel-shaped structure with a larger top and a smaller bottom, and the bottom water collection area is connected to the drainage pipe area.

5. The foundation drainage system for large sand-draining funnels in areas with deep overburden as described in claim 1, characterized in that, The drainage pipe area is arranged on both sides of the sand-drainage corridor (9), with the same slope as the sand-drainage corridor, and adopts a concrete pipe structure; the drainage pipe area is connected to the bottom water collection area, and the water collected in the sand-drainage blind ditch is discharged downstream along the drainage pipe.

Images