Three-dimensional well point drainage construction method for high fill site

Abstract

The application relates to the technical field of drainage treatment, in particular to a three-dimensional spring hole drainage construction method for high fill site, which is characterized in that a vertical drainage body for increasing drainage is vertically arranged around a water outlet point of a spring hole, the vertical drainage body is arranged in a centralized mode or a multi-point mode according to the position and flow of the water outlet point of the spring hole; a part of original soil on the surface of an original foundation is replaced to form a water collecting layer; a water collecting cofferdam is arranged at a distance outside the water outlet point of the spring hole, the water collecting cofferdam surrounds the periphery of the vertical drainage body; a groove is excavated to lay a horizontal flow guide body, two ends of the horizontal flow guide body are connected with the water collecting cofferdam and a main drainage channel respectively, underground water discharged from the spring hole can be drained to the main drainage channel through the horizontal flow guide body and discharged through the main drainage channel. The application has the advantages of good spring hole drainage effect, simple structure, convenient on-site construction, low cost and wide application range.

Description

Technical Field

[0001] This invention relates to the field of drainage treatment technology, and in particular to a method for constructing a three-dimensional spring drainage system on a high-fill site. Background Technology

[0002] With the gradual advancement of my country's strategic planning, urban construction and development have entered a new era. Many Chinese cities are located in mountainous and hilly areas, often requiring large-scale high-fill projects such as "opening mountains and filling valleys" to resolve land use conflicts in urban construction. Underground drainage works play a crucial role in the formation of high-fill sites. If groundwater cannot be drained in time, it will cause backwater within the high fill, leading to a rise in the water level in the original foundation and fill body. Long-term soaking softens the soil and causes additional settlement, triggering secondary geological disasters. It also reduces the shear strength of the soil, causing instability of the original foundation and slopes. In many areas, there is a concentrated and continuous groundwater discharge method: springs. Without treatment, the long-term large volume of water poses a significant threat to the fill foundation.

[0003] The existing conventional solution for treating springs is a spring drainage blind ditch structure (patent number: CN212405096U), which includes a diversion ditch set in the soil layer, geotextile laid at the bottom and sides of the diversion ditch, a drainage pipe installed in the diversion ditch, rubble filled around the drainage pipe, a graded crushed stone filter layer set on top of the rubble, backfill soil on the graded crushed stone filter layer, and geotextile placed between the graded crushed stone filter layer and the backfill soil. This invention patent addresses the need for a single and clearly defined spring outlet. If the location cannot be clearly determined, it is difficult to effectively and conveniently collect groundwater. Furthermore, if there are multiple outlets and a large water volume, it is difficult to meet the requirement of rapid drainage, and the drainage blind ditch is prone to siltation and failure. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a three-dimensional drainage construction method for springs in high-fill sites. This method utilizes a gravel collection layer, a vertical drainage system, a water collection cofferdam, a horizontal guide body, and a drainage cushion layer. The vertical drainage system is constructed vertically around the spring's outlet. A portion of the original soil is replaced to form the collection layer. A water collection cofferdam is then placed a certain distance outward from the spring's outlet. A trench is excavated to lay the horizontal guide body, connecting the water collection cofferdam and the main drainage channel. A drainage cushion layer of a certain thickness is laid on the upper surface of the site, forming a complete spring drainage structure system that effectively drains springs in high-fill sites.

[0005] The objective of this invention is achieved through the following technical solutions: A method for constructing a three-dimensional spring drainage system on a high-fill site, characterized in that the construction method includes: Vertical drainage structures are constructed around the spring's outlet point for increased drainage. The arrangement of these vertical drainage structures can be centralized or multi-point, depending on the location and flow rate of the spring's outlet point. A water catchment layer was created by replacing part of the original soil on the surface of the original foundation. A water collection cofferdam is arranged at a certain distance outside the outlet of the spring, and the water collection cofferdam surrounds the periphery of the vertical drainage body; A trench is excavated and a horizontal guide tube is laid. The two ends of the horizontal guide tube are connected to the water collection cofferdam and the main drainage channel, respectively. The groundwater discharged from the spring can be discharged to the main drainage channel through the horizontal guide tube and then discharged through the main drainage channel.

[0006] When the spring has a single and clear outlet location or a small flow rate, the vertical drainage system is arranged in a centralized manner, with the entire vertical drainage system vertically installed around the spring, and the diameter of the vertical drainage system is 1.0-1.5m.

[0007] When the location of the spring's outlet is unclear and there are many or the flow rate is large, the vertical drainage body is arranged in a multi-point manner, with multiple relatively independent vertical drainage bodies set around the spring, and the diameter of the vertical drainage body is 0.5-0.8m.

[0008] The vertically increasing volume of the multi-point structure is arranged in a plum blossom or rectangular shape, covering each water outlet of the spring.

[0009] The vertical filler body is constructed by layering graded crushed stone. Along the height of the vertical filler body, the particle size of the filler gradually decreases from top to bottom, wherein the particle size range of the filler is 2-10cm.

[0010] The water collection cofferdam is constructed of concrete or masonry, with three sides closed and one end open. The location of this opening corresponds to the location of the horizontal guide flow. The wall thickness of the water collection cofferdam is not less than 0.5m.

[0011] The horizontal guide includes fine stone and coarse stone, wherein the fine stone is filled inside the coarse stone, and a plastic blind trench is embedded in the fine stone.

[0012] A filter layer is provided around the horizontal guide fluid and at its ends.

[0013] The water collection layer is a gravel water collection layer.

[0014] Depending on the highest groundwater level and the flow rate of the spring, if it is significantly higher than the original ground surface, a drainage cushion layer of a certain thickness composed of coarse-grained stones, with a particle size of 5-30cm, should be filled on top of the spring drainage structure.

[0015] The advantages of this invention are: 1) Under the load of high embankment, the drainage structure of the present invention is not affected by the uneven settlement of the foundation, has a long service life, and still has a good groundwater drainage function.

[0016] 2) Depending on the size of the underground drainage flow at the site, vertical drainage bodies (centralized or multi-point) are installed at the spring outlet to effectively form multiple drainage channels, accelerate the discharge of groundwater from the spring, and reduce the upwelling force of groundwater. The vertical drainage bodies are composed of variable-graded crushed stone, which can effectively filter groundwater and prevent soil erosion.

[0017] 3) The ground surface above the water collection cofferdam and horizontal diversion channel is paved with crushed stone drainage layer. Even during the rainy season, it can effectively collect and store groundwater in the short term and gradually discharge it. It is not easily affected by factors such as soaking and softening, and has a certain safety reserve.

[0018] 4) The main material is composed of crushed stone, which has the advantages of low cost, good long-term stability, convenient construction and time saving. Attached Figure Description

[0019] Figure 1 This is a plan view of the present invention; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a detailed planar layout (centralized) of the vertically increasing arrangement of the structures in this invention. Figure 4 This is a detailed planar layout (multi-point) of the vertically increasing arrangement of the structures in this invention. Figure 5 This is a detailed cross-sectional view of the vertically increasing structure in this invention; Figure 6 This is a schematic diagram of the cross-section of the horizontal guide fluid in this invention. Detailed Implementation

[0020] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art: like Figure 1-6 As shown in the figure, each of the markings represents: spring 1, vertical drainage body 2, fine granular material 2-1, coarse granular material 2-2, crushed stone water collection layer 3, water collection cofferdam 4, horizontal flow guide 5, main drainage channel 6, drainage cushion layer 7, non-woven geotextile 8, plastic blind drain 9, upper section crushed stone A, middle section crushed stone B, lower section crushed stone C.

[0021] Example: Figures 1 to 6 As shown in the figure, the three-dimensional spring drainage construction method in this embodiment is used to realize the drainage of spring 1, which is located under the high fill.

[0022] Specifically, combined Figures 1 to 6 As shown, the spring drainage construction method in this embodiment includes the following steps: 1) First, based on the on-site survey data, explore the distribution of the water outlet of spring 1, monitor the discharge flow of groundwater from the spring, estimate the maximum flow of spring 1 once in a hundred years, and analyze the design of the horizontal guide 5.

[0023] 2) Based on the distribution and flow rate of spring 1, a centralized or multi-point structure can be selected for the planar arrangement of the vertical drainage body 2. The vertical drainage body 2 is installed vertically with the water outlet of spring 1 as the center to achieve the drainage effect.

[0024] like Figure 3 As shown, when the outlet of spring 1 is located in a single and clear position or the flow rate is small (sixth-eighth level spring, flow rate ≤ 56L / s), a centralized layout is selected. Specifically, the vertical drainage body 2 is installed vertically around spring 1, that is, the vertical drainage body 2 surrounds the entire spring 1. The diameter of the vertical drainage body should be 1.0m-1.5m.

[0025] like Figure 4 As shown, when the outlet of spring 1 is unclear and there are many outlets or the flow rate is large (first-level spring to fifth-level spring, flow rate > 56L / s), a multi-point layout is selected. Specifically, multiple independent vertical drainage bodies 2 are vertically installed around multiple adjacent springs 1. The number of vertical drainage bodies 2 is not limited to 4, and the arrangement can be quincunx or rectangular, etc., to cover all outlets of spring 1. The diameter of the vertical drainage bodies 2 should be 0.5m-0.8m, and the number should not be less than 2, so as to achieve the drainage effect.

[0026] In this embodiment, as Figure 5 As shown, the vertical drainage body 2 should be in the form of a crushed stone pier. To ensure the passage of groundwater without carrying away soil particles, a filter layer should be installed at the bottom. The length of the pier should extend to the top surface of the bedrock. The pier material should be divided into three sections from top to bottom in the height direction: upper crushed stone A, middle crushed stone B, and lower crushed stone C. The particle size range of each crushed stone section should be 2-10cm, gradually decreasing from top to bottom. The height of the middle crushed stone B and lower crushed stone C piers should not be less than 2m, serving to filter groundwater while draining and depressurizing.

[0027] 3) If the original foundation is soft cohesive soil, after the vertical drainage body is constructed, graded crushed stone is used to replace the surface foundation soil to form a crushed stone water collection layer 3 with a thickness of not less than 0.5m and the outer boundary is extended a certain distance from the vertical drainage body 2. This crushed stone water collection layer 3 can prevent the cofferdam foundation from being soaked and causing settlement, which would affect the cofferdam structure. On the other hand, it can expand the surface spring outlet points to better collect groundwater and filter impurities in the groundwater to prevent siltation.

[0028] 4) Set up a water collection cofferdam 4 around the periphery of the gravel water collection layer 3. The cofferdam structure is constructed by masonry or concrete, with masonry on three sides and an opening on one side. The thickness of the cofferdam sidewall structure is not less than 0.5m. The horizontal guide 5 is inserted into the water collection cofferdam 4 and pushed against the other sidewall. The remaining gaps are filled with gravel.

[0029] 5) Excavate the trench for the horizontal guide channel 5 and install the horizontal guide channel 5. The horizontal guide channel 5 should have a certain slope along its direction and connect the water collection cofferdam 4 and the main drainage channel 6. It should be located directly above the spring 1, and a filter layer should be installed around its perimeter and at its ends. The cross-sectional flow capacity of the horizontal guide channel 5 should meet the flow rate of the groundwater from the spring. It can adopt a structure such as a rock-filled blind ditch + drainage culvert or pipe culvert. A filter layer, such as non-woven geotextile 8, should be installed around its perimeter and at both ends. The cross-sectional dimensions of the horizontal guide channel 5 should generally not be less than 2m. 2 It can be a rectangle or an inverted trapezoid.

[0030] like Figure 6 As shown, in this embodiment, the horizontal guide fluid 5 is provided with a plastic blind drain 9 in the non-woven geotextile 8 of the seat filter layer. The plastic blind drain 9 is buried in the fine granular material 2-1, and coarse granular material 2-2 is filled around the fine granular material 2-1.

[0031] 6) Connect the other side of the horizontal guide 5 to the main drainage channel 6 to ensure that the groundwater of the spring 1 can be drained in a timely manner.

[0032] 7) Depending on the highest groundwater level and spring flow rate, if it is significantly higher than the original ground surface, a drainage cushion layer 7 of a certain thickness should be constructed on top of the spring drainage structure system. This cushion layer should be composed of coarse-grained stones with a particle size of 5-30cm. When the groundwater level is high or the short-term rainfall in the upper part is large, the drainage cushion layer 7 can temporarily collect, gather, and store groundwater, unaffected by soaking and softening, and also has a certain drainage function, thereby improving the safety of the underground drainage system.

[0033] In this specific implementation example, the treatment of an underground spring in a high embankment site is taken as an example. The estimated flow rate of the spring is 40L / s, the original foundation is red clay, and the backfill thickness of the upper part of the site is relatively large, about 70m.

[0034] The structure adopts a multi-point vertical arrangement, with 4 square piers spaced 1.5m apart. The pier diameter is 0.8m, and its bottom is the top of the bedrock surface. The pier length is about 15m. The pier material is carbonate crushed stone, and the particle size of the pier varies in 3 segments, from top to bottom: 5-10cm, 3-7cm, and 2-5cm.

[0035] The thickness of the crushed stone water collection layer 3 shall not be less than 1m, the particle size of the crushed stone shall not be greater than 20cm, the solid volume ratio shall not be less than 0.75, and the paving range of the crushed stone water collection layer shall extend no less than 5m on each side from the water outlet point, and the surface surfacing density shall not be less than 5%.

[0036] The water collection cofferdam 4 is constructed with M7.5 mortar-grouted stone masonry. The net internal dimensions of the cofferdam are not less than 3.0m (length) × 2.5m (width) × 2.0m (height), and the thickness of the cofferdam is not less than 0.5m.

[0037] Horizontal drainage system 5 utilizes both gravel and plastic blind drains. The filler material is carbonate rock with a saturated single compressive strength of not less than 30 MPa, and exhibits continuous and good gradation. The plastic blind drain has an external diameter of 300 mm, a hollow diameter of 220 mm, a weight of 5800 g / m³, and a compressive strength of 45 kPa. It is wrapped with non-woven geotextile around the edges and ends, with a unit area mass of not less than 200 g / m³. 2 Grip strength > 1.4KN, tear strength > 0.5KN, puncture strength > 0.5KN, CBR burst strength > 1.4N, permeability > 0.01cm / s.

[0038] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.

Claims

1. A method for constructing a three-dimensional spring drainage system on a high embankment site, characterized in that: The construction method includes: Vertical drainage structures are constructed around the spring's outlet point for increased drainage. The arrangement of these vertical drainage structures can be centralized or multi-point, depending on the location and flow rate of the spring's outlet point. A water catchment layer was created by replacing part of the original soil on the surface of the original foundation. A water collection cofferdam is arranged at a certain distance outside the outlet of the spring, and the water collection cofferdam surrounds the periphery of the vertical drainage body; A trench is excavated and a horizontal guide is laid. The two ends of the horizontal guide are connected to the water collection cofferdam and the main drainage channel, respectively. The groundwater discharged from the spring can be discharged to the main drainage channel through the horizontal guide and then discharged through the main drainage channel.

2. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: When the spring has a single and clear outlet location or a small flow rate, the vertical drainage system is arranged in a centralized manner, with the entire vertical drainage system vertically installed around the spring, and the diameter of the vertical drainage system is 1.0-1.5m.

3. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: When the location of the spring outlet is unclear and there are many or the flow rate is large, the vertical drainage body is arranged in a multi-point manner, with multiple relatively independent vertical drainage bodies set around the spring outlet, and the diameter of the vertical drainage body is 0.5-0.8m.

4. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 3, characterized in that: The vertically increasing volume of the multi-point structure is arranged in a plum blossom or rectangular shape, covering each water outlet of the spring.

5. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: The vertical filler body is constructed by layering graded crushed stone. Along the height of the vertical filler body, the particle size of the filler gradually decreases from top to bottom, wherein the particle size range of the filler is 2-10cm.

6. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: The water collection cofferdam is constructed of concrete or masonry, with three sides closed and one end open. The location of this opening corresponds to the location of the horizontal guide flow. The wall thickness of the water collection cofferdam is not less than 0.5m.

7. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: The horizontal guide includes fine stone and coarse stone, wherein the fine stone is filled inside the coarse stone, and a plastic blind trench is embedded in the fine stone.

8. A method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1 or 7, characterized in that: A filter layer is provided around the horizontal guide fluid and at its ends.

9. The method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: The water collection layer is a gravel water collection layer.

10. A method for constructing a three-dimensional spring drainage system on a high embankment site according to claim 1, characterized in that: Depending on the highest groundwater level and the flow rate of the spring, if it is significantly higher than the original ground surface, a drainage cushion layer of a certain thickness composed of coarse-grained stones, with a particle size of 5-30cm, should be filled on top of the spring drainage structure.

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