Ecological street drainage structure
Technical Field
The invention relates to a drainage structure, in particular to an ecological street drainage structure.
Background
At present, the street drainage design of cities in China still mainly adopts pipeline drainage, ditch drainage is mainly adopted at suburbs or urban and rural junctions, and the general idea of treating rainwater is still embodied in a 'drainage' shape. With the rapid development of urbanization in recent years, the defects of traditional urban street drainage become more obvious, and the road drainage system which takes simple drainage as a single mode and a target exposes a plurality of problems. In the urban expansion process, a large amount of natural ground is gradually replaced by hardened surfaces including roads, and the hardening rate of the peripheral areas of the roads is increased day by day. The increase of the impervious area leads to the increase of the urban comprehensive runoff coefficient, the torrential rain confluence is rapid, the runoff quantity and the runoff peak value are multiplied, and the street drainage pressure is too heavy; the road pollutes the water around the line seriously. Besides pollutants such as heavy metals and hydrocarbons which are harmful to the environment, pollutants such as oils and the like brought by vehicle operation, waste discarded by pedestrians and debris and pollutants on streets flushed from courtyards and other open lands are finally migrated into the water environment under the action of rainwater leaching and flushing, and the pollutants are harmful to the water areas; in addition, the water demand of cities is increasing day by day, and the rainwater on the road surface and the surrounding areas flows away from the urban rainwater and sewage pipe network by the traditional street drainage, so that a large amount of precious rainwater resources are wasted, and the urban drainage pipe network, the sewage treatment plant and the water environment are overwhelmed.
Disclosure of Invention
The purpose of the invention is as follows: the invention provides an ecological street drainage structure which can reduce road surface runoff and flood peak flow and relieve street drainage pressure; and can also collect, filter, purify through unifying the rainwater when solving the street drainage problem, reach and slow down the peak discharge, avoid the rainwater infiltration of pollution, replenish the purpose of ground water source.
The invention content is as follows: an ecological street drainage structure comprises a roadway, a curb, a rainwater planting pool, pedestrian passages among the planting pools and a permeable pavement; the pavement of the roadway is made of densely-distributed asphalt concrete material, and the transverse gradient of the pavement is 2.5%; the curb is provided with two openings at the rainwater planting pool, and a rainwater buffer zone is arranged between the curb and the rainwater planting pool, so that rainwater can conveniently flow into the planting pool; the inlet of the rainwater planting pool is of a stepped structure, so that rainwater flows in a grading manner to form a water-stacking landscape; the bottom structure of the rainwater planting pool sequentially comprises a planting soil layer, an artificial packing layer, a sand layer and a gravel layer from top to bottom, and perforated pipes are buried in the gravel layer; the sidewalk and the pedestrian passageway are paved by adopting water permeable pavement bricks, and the water permeable pavement bricks are sequentially paved into a water permeable brick surface layer, a buffer layer and a gravel base layer from top to bottom; impermeable geotextile is arranged between the sidewalk and the pavement base layer and the cushion layer of the pedestrian passageway, and a drainage pipeline is arranged between the permeable surface layer at the edge of the sidewalk and the impermeable geotextile and leads to the rainwater planting pool.
The stepped structure at the inlet of the rainwater planting pool is formed by laying basalt weirs.
In order to enable water flow on the roadway to smoothly flow into the rainwater planting pool, one side of the rainwater buffering zone close to the roadway is highly flush with the roadway, and one side of the rainwater buffering zone close to the rainwater planting pool is inclined downwards to form a certain slope.
The working principle is as follows: the roadway is an impervious pavement, so that rainwater is collected to the edge of the road through the transverse gradient of the road, enters the rainwater buffer zone through the opening of the curb stone, and then enters the rainwater planting pond through the rainwater buffer zone; the sidewalk and the pedestrian passageway are paved by adopting permeable pavement bricks, rainwater can rapidly infiltrate downwards, and the infiltrated rainwater is drained to the rainwater planting pool through a drainage pipeline below the sidewalk pavement. The polluted rainwater forms a water-stacking landscape when flowing into the stepped basalt weir at the inlet of the rainwater planting pool, and the speed of rainwater downwards flowing is slowed down, so that the rainwater has sufficient time to seep downwards in the planting pool. Polluted rainwater is filtered and purified in the environments of vegetation, soil and the like, and the percolated rainwater is collected by the perforated pipes in the gravel layer at the bottom and enters other drainage systems.
Has the advantages that: the street drainage structure of the invention collects the street rainwater into the rainwater planting pool for filtration and infiltration, purifies the rainwater in a natural simulation mode, and collects and reuses the rainwater.
Permeable pavement can reduce road surface runoff effectively and improve the surface gathered water situation, and ordinary permeable pavement lets the rainwater naturally infiltration, and in order to avoid the rainwater infiltration of pollution to pollute road bed and ground water source, need set up the higher filtration of cost, water storage equipment etc. under the road surface structure. Compared with the prior art, the rainwater planting method has the advantages that a simpler and cheaper mode is adopted, the impermeable geotextile is arranged between the pavement base layer and the cushion layer to prevent rainwater from continuously seeping into the base layer, the drainage pipe is arranged below the permeable brick surface layer, and the polluted rainwater which cannot seep into the nearby rainwater planting pool through the drainage pipe. The invention well structures the drainage structures of two road surfaces together, and collects polluted rainwater together for common treatment, thereby not only avoiding sewage infiltration, but also saving cost.
In consideration of the fact that the peak rainwater amount collected by the rainwater planting pool in the street drainage structure is larger, the basalt weir is arranged at the rainwater inflow position to enable rainwater to flow in a grading mode.
Drawings
FIG. 1 is a plan view of an ecological street drainage structure of the present invention;
fig. 2 is a sectional view a-a of the drainage structure of the ecotype street according to the present invention.
Detailed Description
As shown in the figure, the ecological street drainage structure comprises a roadway 1, a curb 2, a rainwater buffer zone 3, a rainwater planting pool 4, a sidewalk 5, a pedestrian passage 6 and a drainage pipeline 7; the pavement material of the roadway 1 adopts densely-distributed asphalt concrete, and the transverse gradient of the pavement is 2.5%; the curb stones 2 are arranged on two side edges of the roadway 1, openings are formed in the positions, where the rainwater planting pools 4 are located, of the curb stones 2, the openings are in a round angle shape, and the width and the height of each curb stone 2 are 150 mm; a rainwater buffer zone 3 is arranged between the kerbstone 2 and the rainwater planting pool 4, one side of the rainwater buffer zone 3, which is close to the kerbstone 2, is flush with the height of the roadway 1, the other side of the rainwater buffer zone inclines downwards, and the inclination of the rainwater buffer zone is 20%; a stone step 41 is arranged at the inlet of the rainwater planting pool 4, and the stone step 41 is formed by paving basalt weirs, so that rainwater can flow in a grading manner to form a water-stacking landscape; the sidewalks 5 and the pedestrian passageways 6 are level in height and adopt permeable pavement pavements 51, a cushion layer is laid below the permeable pavement pavements 51, and impermeable geotextiles 52 are arranged between the broken stone base layers of the permeable pavement pavements 51 of the sidewalks 5 and the pedestrian passageways 6; a drainage pipeline 7 is arranged between the permeable pavement 51 of the sidewalk 5 and the impermeable geotextile 52, and the drainage pipeline 7 is communicated with the rainwater planting pool 4; the sidewalk 5 and the pedestrian passageway 6 are raised by 200mm compared with the roadway 1 due to the characteristics that accumulated water on the road surface needs to be quickly eliminated and the traffic load is less.
As shown in fig. 2, the permeable pavement structure layers of the sidewalk 5 and the pedestrian passageway 6 are a permeable brick surface layer of 60mm, a buffer layer of 30mm, and a graded broken stone base layer of 150mm from top to bottom, and a lime soil cushion layer of 120mm is laid below the permeable pavement 51 and the impermeable geotextile 52. The rainwater planting pool 4 comprises a stone step 41, a bark covering layer 42, a vegetation and planting soil layer 43, an artificial packing layer 44, a sand layer 45 and a gravel layer 46 from top to bottom, and a perforated pipe 47 is embedded in the gravel layer 46. The bark covering 42 has an average thickness of 60 mm; the vegetation and planting soil layer 43 is 250mm, and perennial herbaceous plants are planted; the artificial filler layer 44 is made of artificial material with strong permeability and the thickness is 600 mm; the thickness of the sand layer 45 is 150 mm; the gravel layer 46 is composed of gravel having a diameter of less than 50mm, has a thickness of 200mm, and allows the burying of perforated pipes 47 having a diameter of 80 mm. The area of a specific rainwater planting pool is mainly related to the effective capacity, the runoff of treated rainwater and the permeability of the treated rainwater, and is determined according to specific conditions.