CN207714473U - A kind of Rain Garden suitable for clay area - Google Patents

Abstract

The utility model discloses a rainwater garden suitable for clay areas, which comprises a sleeve, a gravel layer, a permeable geotextile, a planting soil layer, a covering layer and a water storage layer arranged sequentially from bottom to top; the bottom of the sleeve is vertically inserted into the Set in the gravel layer, the top of the sleeve is flush with the top of the covering layer, and the sleeve is filled with pebbles. A blind drainage pipe is buried in the gravel layer, and a perforation is arranged on the blind drainage pipe, and the perforation is connected with the vertical overflow port through a connecting pipe. The utility model can avoid large-scale replacement or improvement of the undisturbed soil while maintaining the rainwater retention and purification functions, effectively reduces construction investment and construction difficulty, is conducive to the promotion of rain gardens in clay areas, and conforms to the national promotion of sponge city construction. total requirements.

Description

A rain garden for clay soils

technical field

The utility model relates to the technical field of municipal engineering, in particular to a rainwater garden suitable for clay areas.

Background technique

In order to solve the increasingly serious waterlogging and non-point source pollution problems in cities in recent years, the construction of sponge cities has become the consensus of the industry and the mandatory requirements of the country. The "Guiding Opinions of the General Office of the State Council on Promoting the Construction of Sponge City" (Guo Ban Fa [2015] No. 75) issued on October 6, 2015 clearly requires that 70% of the rainfall be absorbed locally through the construction of sponge cities. and utilization; by 2020 and 2030, the area of urban built-up areas meeting the requirements for sponge city construction will reach 20% and 80% respectively.

One of the cores of sponge city construction is to promote low-impact development stormwater facilities. Common low-impact development stormwater facilities include rain gardens, grass planting ditches, sunken green spaces, bioretention ponds, rainwater wetlands, rainwater wet ponds, planted roofs, etc. The rain garden refers to a small area of green land with shrubs and flowers as the main vegetation, all or part of which is sunken. It is used to collect rainwater from itself and the surrounding area. It can temporarily retain rainwater and use soil and plants to purify rainwater. At the same time, it has certain landscape effect. Compared with other low-impact development rainwater facilities, the rain garden has more complete functions (it can store rainwater, alleviate the impact of waterlogging, intercept and purify rainwater, and improve the water environment), and has better landscape. In addition, it occupies a small area, There are few restrictive factors and can be arranged according to local conditions. Therefore, rain gardens are the most widely used technology for sponge city construction.

As shown in Figure 1, the general structure of a common rain garden includes a water storage layer 1 (100-300 mm), a cover layer 2 (50-80 mm), and a planting soil layer 3 (the thickness of the planting soil layer is determined by the type of plant. Herbaceous plants should not be less than 250 mm, and shrubs should not be less than 650 mm), artificial filler layer 4 (the thickness of the artificial filler layer is about 300-500 mm, which is determined by the local rainfall characteristics and the catchment area of the rain garden), sand layer 5 (100-150 mm), gravel layer 6 (200-300 mm), overflow outlet 7 and drainage blind pipe 8, etc.

The key to the success of the rain garden is to maintain good permeability of the overall structure, and the permeability of the overall structure mainly depends on the planting soil layer and the artificial filling layer, so strict requirements are put forward for the materials of the planting soil layer and artificial filling layer, such as " The Jiangsu Provincial Rain Garden Construction and Operation and Maintenance Guide stipulates: "If the undisturbed soil has good permeability (the permeability coefficient is greater than 36 mm/hour, that is, 1×10-5 m/s), the undisturbed soil can be used as the planting soil layer; If the original soil cannot meet the requirements, the original soil can be improved or directly replaced. The main components and contents of the improved or replaced soil are suggested as follows: the sand content accounts for 60% to 75%, and the organic component content accounts for 15% to 20%. The clay content should not exceed 10-20%; if a commercial product is used, the ex-factory value should not be lower than 150mm/hour, and not lower than 80mm/hour after three years."

Clay is widely distributed in southern my country, especially in the Yangtze River Delta Plain, Pearl River Delta Plain, and Jianghuai Plain. The surface soil is mainly clay. The permeability coefficient of clay is generally less than 5×10-9 m/s, and the permeability coefficient of silty clay is generally 5×10-9 ~5×10-8 m/s; if the above requirements are followed, the undisturbed soil must be Improvement or direct replacement of soil (mainly sandy loam soil of commercial products), requires a large amount of engineering and high construction investment. The above situation has seriously affected the construction and promotion of rain gardens in clay areas.

Utility model content

The technical problem to be solved by the utility model is to provide a rain garden suitable for the clay area in view of the deficiencies of the above-mentioned prior art. The rain garden suitable for the clay area can avoid Large-scale replacement or improvement of undisturbed soil can effectively reduce construction investment and construction difficulty, which is conducive to the promotion of rain gardens in clay areas and meets the overall requirements of the country to promote the construction of sponge cities.

In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is:

A rain garden suitable for clay areas, comprising a sleeve and a gravel layer, a permeable geotextile, a planting soil layer, a cover layer and an aquifer laid in sequence from bottom to top; the bottom of the sleeve is inserted vertically in the gravel layer , the top of the sleeve is flush with the top of the covering layer, and the sleeve is filled with pebbles.

A blind drainage pipe is buried in the gravel layer, and a perforation is arranged on the blind drainage pipe, and the perforation is connected with the vertical overflow port through a connecting pipe.

The bottom outlet of the vertical overflow leads to a storm sewer or channel.

The top of the sleeve and pebbles is piled with landscape rocks.

The pebbles inside the sleeve form several pebble layers, and each pebble layer is wrapped with a geogrid.

The mesh aperture of the geogrid is less than 10mm.

The sleeve is a UPVC pipe with a diameter of 300-600mm.

The thickness of the gravel layer is more than 600mm, and the diameter of the gravel in the gravel layer is 50-80mm.

After the utility model adopts the above structure, it has the following remarkable effects:

1. The present invention can use clay-based undisturbed soil as the planting soil while maintaining the rainwater retention and purification functions, cancels the artificial filling layer, avoids the usual large-scale soil replacement or soil improvement, and reduces the cost by 30% ~50%, while the construction process and construction difficulty are also simplified and reduced.

2. Since the surrounding undisturbed soil is mainly clay, and the gravel layer is further thickened, the water storage and water retention capacity of the present invention is further improved; when the thickness of the gravel layer exceeds 600 mm, the plants in the rain garden generally do not need to Watering, the water storage of the gravel layer is sufficient to meet the growth needs of the plants. Therefore, the present invention is particularly suitable for the clay-based soil with an annual precipitation of 800-900 millimeters.

Description of drawings

Figure 1 shows a schematic structural view of a rain garden in the prior art.

Fig. 2 shows a structural schematic diagram of a rain garden suitable for clay areas of the present invention.

Including:

1. Aquifer; 2. Covering layer; 3. Planting soil layer; 4. Artificial packing layer; 5. Sand layer; 6. Gravel layer; 7. Vertical overflow outlet; 8. Drainage blind pipe; 9. Bottom Water outlet; 10. Permeable geotextile; 11. Sleeve; 12. Pebble; 13. Landscape rockfill; 14. Connecting pipe; 15. Undisturbed soil.

Detailed ways

The utility model will be described in further detail below in conjunction with the accompanying drawings and specific preferred embodiments.

As shown in FIG. 2 , a rain garden suitable for clay areas includes a sleeve 11 and a gravel layer 5 , a permeable geotextile 10 , a planting soil layer 3 , a covering layer 2 and an aquifer 1 sequentially arranged from bottom to top.

The thickness of the above-mentioned gravel layer is preferably more than 600 mm, generally 800-1000 mm, and the diameter of the gravel in the gravel layer is preferably 50-80 mm.

The sleeve is preferably a UPVC pipe with a diameter of 300-600 mm.

The bottom of the sleeve is vertically inserted into the gravel layer, the top of the sleeve is flush with the top of the covering layer, and the sleeve is filled with pebbles 12 to form a pebble column.

Pebble pillars can be installed in multiple places, with an average of 10-20 square meters.

The pebbles in the sleeve form several pebble layers, and each pebble layer is preferably wrapped with a geogrid, and the mesh aperture of the geogrid is preferably less than 10mm.

A drainage blind pipe is buried in the gravel layer, and a perforation is arranged on the drainage blind pipe. The perforation communicates with the vertical overflow port 7 through a connecting pipe, and the bottom water outlet 9 of the vertical overflow port leads to a rainwater pipe channel or a river.

Landscape rockfills are preferably stacked on the tops of the above-mentioned sleeves and pebbles and the outer periphery of the vertical overflow outlet.

The construction process of the rain garden for this application is as follows: After the earthwork of the rain garden is excavated to the design elevation at the bottom of the structure, the drainage blind pipe is laid first, and then gravel with a diameter of 50-80 mm (the gravel can be replaced by construction waste such as broken bricks) is laid to the design elevation , then install the UPVC pipe (diameter 300-600 mm), and fill the casing with pebbles (can be replaced by gravel) with a diameter of 20-50 mm, and finally construct the permeable geotextile, planting soil, planting soil layer, and vertical overflow port in sequence And plant plants, and stack yellow graded river pebbles with a diameter of 30-120 mm on the top of the casing and around the vertical overflow to improve the comfort of the landscape.

Since the suspended matter in the rainwater will be trapped in the pebble column in the casing, in order to facilitate periodic cleaning, the filled pebbles can be wrapped with geogrid (the mesh diameter is less than 10mm) and put into the casing in layers.

The application works as follows:

(1) During the rainy period, the rainwater from the surrounding ground first collects on the surface of the rain garden, and then infiltrates down to the gravel layer through the pebble pillars. The pollutants in the rainwater are intercepted by the pebble pillars, and the clean rainwater is accumulated in the gravel layer; More, the water storage level of the rain garden gradually rises until it exceeds the normal water storage level and is discharged through the vertical overflow port.

(2) After the rain is over, the water storage level of the rain garden drops rapidly to the top of the gravel layer through the drainage of the blind drainage pipe, so as to avoid affecting the long-term drainage of the plants in the rain garden; the rainwater accumulated in the gravel layer passes through the micropores in the soil The siphon effect can meet the long-term growth needs of plants in the rain garden.

The preferred embodiment of the utility model has been described in detail above, but the utility model is not limited to the specific details in the above-mentioned embodiment, and within the scope of the technical concept of the utility model, various equivalent transformations can be carried out to the technical solution of the utility model , these equivalent transformations all belong to the protection scope of the present utility model.

Claims (8)

1. a kind of Rain Garden suitable for clay area, it is characterised in that：It lays successively including sleeve and from bottom to up Gravel layer, permeable geotextiles, planting soil layer, coating and aquifer；The bottom of sleeve is vertically plugged in gravel layer, sleeve Top and flush at the top of coating, sleeve is interior to be filled with cobble.

2. the Rain Garden according to claim 1 suitable for clay area, it is characterised in that：The row of being embedded in gravel layer Water blind pipe, draining blind pipe are equipped with perforation, this is punched through connecting tube and is connected with vertical overflow port.

3. the Rain Garden according to claim 2 suitable for clay area, it is characterised in that：The bottom of vertical overflow port Water outlet leads to Storm Sewer System or river.

4. the Rain Garden according to claim 1 suitable for clay area, it is characterised in that：The top of sleeve and cobble Heap is equipped with landscape enrockment.

5. the Rain Garden according to claim 1 suitable for clay area, it is characterised in that：Cobble in sleeve is formed Several boulder beds, each boulder bed are all made of earthwork grid package.

6. the Rain Garden according to claim 5 suitable for clay area, it is characterised in that：The grid hole of earthwork grid Diameter is less than 10mm.

7. the Rain Garden according to claim 1 suitable for clay area, it is characterised in that：Sleeve is diameter in 300- The UPVC of 600mm is managed.

8. the Rain Garden according to claim 1 suitable for clay area, it is characterised in that：Gravel layer laying depth is super 600mm is crossed, the gravel diameter in gravel layer is 50-80mm.