A construction method for greening and planting in coastal saline-alkali land

Abstract

This invention relates to a construction method for greening and planting in coastal saline-alkali land, comprising: 1. excavating the original soil of the coastal saline-alkali land and digging a trench at the bottom of the foundation pit; 2. laying drainage pipes along the length of the trench; 3. laying crushed stone outside the drainage pipes to form a first crushed stone layer; 4. laying original soil above the upper trench to form a guide slope; 5. laying a first waterproof layer along the guide slope; 6. laying crushed stone above the first waterproof layer to form a second crushed stone layer; 7. filling the guide slope with original soil, filling it to the top of the second crushed stone layer and forming a raised area of ​​original soil, with a guide slope forming around the side of the raised area, and laying a second waterproof layer above the raised area; 8. filling the second crushed stone layer above the outer side of the second waterproof layer with original soil, and then filling with planting soil; 9. planting green plants within the planting soil area. This invention combines soil replacement with salt removal to ensure that the needs of greening and planting can be met as early as possible, and to ensure that the plants can grow towards the surrounding environment later.

Description

Technical Field

[0001] This invention relates to the field of landscaping construction in saline-alkali land, specifically to a method for planting and afforestation in coastal saline-alkali land. Background Technology

[0002] In coastal saline-alkali areas, the soil is severely salinized, making it unsuitable for planting greenery and resulting in low survival rates for green plants. During the rainy season, the salt in the soil is washed away by rainwater infiltration, but during relatively dry seasons, the underground salt will return due to evaporation.

[0003] Existing technologies typically employ measures such as desalination and soil replacement to address the problem of soil salinization. For example, the utility model patent with publication number CN204047087U discloses a water filter hose desalination and isolation layer salt prevention system. This system involves digging trenches in saline-alkali land, laying a coarse sand layer at the bottom of the trenches, burying permeable blind pipes in the coarse sand layer, laying a gravel layer on top of the coarse sand layer, laying a straw layer on top of the gravel layer, and finally laying a mixed soil and planting soil on top of the straw layer.

[0004] Existing technologies also include a coastal green space desalination construction process disclosed in CN110419284A, which involves excavating the original soil to form planting pits, excavating blind ditches at the bottom of the planting pits, laying coarse sand and desalination pipes in the blind ditches, laying an isolation layer formed by geotextile and geomembrane on the walls of the planting pits, with the bottom of the isolation layer extending to the bottom of the planting pits, setting a gravel layer and straw mats above the blind ditches, and finally backfilling the planting pits with planting soil.

[0005] Existing desalination methods rely on water infiltration to remove salt from the soil and prevent salt return through isolation and filtration. However, in the early stages of planting, salt remains in the soil, requiring a period of desalination before the soil can meet planting needs. During this period, it is impossible to control salt return, resulting in less than ideal desalination effects. Furthermore, existing methods restrict the space surrounding the green planting area, creating a barrier between the green area and the outside world, which hinders the horizontal development of green spaces. Summary of the Invention

[0006] To address this technical problem, this invention provides a construction method for greening and planting in coastal saline-alkali land. This method combines soil replacement with salt removal to ensure that the soil in the greening and planting area can meet the needs of greening and planting as soon as possible, without forming an isolation barrier between the greening and planting area and the surrounding soil, thus ensuring that the greening plants can expand and grow into the surrounding environment later.

[0007] The technical objective of this invention is achieved through the following technical solution:

[0008] A method for planting vegetation on coastal saline-alkali land, comprising the following steps:

[0009] Step 1: Excavate the original soil of the coastal saline-alkali land to form a foundation pit. The horizontal area of ​​the foundation pit is larger than the area of ​​the green planting area. Dig a trench at the bottom of the foundation pit. The trench has a bottom trench and an upper trench. The side walls of the bottom trench are set at an incline. The upper trench connects to the bottom trench and extends laterally outward along the upper part of the slope of the bottom trench to form a wing trench.

[0010] Step 2: Lay a drainage pipe along the length of the trench, the drainage pipe being provided with drainage holes;

[0011] Step 3: Lay gravel outside the drain pipe, filling the upper trench with gravel to form the first gravel layer;

[0012] Step 4: Lay the original soil on the top of the upper trench. Set a guide slope around the side wing trench on one side of the upper trench. The upper opening of the guide slope is larger than the lower opening. The lower opening of the guide slope receives the gravel in the side wing trench.

[0013] Step 5: Lay the first waterproof layer along the guide slope. The first waterproof layer extends upward along the guide slope along the lower opening edge and extends outward in a horizontal direction from the upper opening edge of the guide slope.

[0014] Step 6: Lay crushed stone on top of the first waterproof layer to form a second crushed stone layer. The crushed stone of the second crushed stone layer extends upward along the lower edge of the opening of the guide slope to a height higher than the first waterproof layer extending horizontally.

[0015] Step 7: Fill the guide slope with original soil, filling it to the top of the second gravel layer and forming a soil protrusion. A guide slope is formed around the side of the soil protrusion. The bottom of the guide slope is set near the outer side of the guide slope. A second waterproof layer is laid on top of the soil protrusion.

[0016] Step 8: Fill the original soil above the second gravel layer outside the second waterproof layer to the height of the upper edge of the foundation pit, and then fill the planting soil above the second waterproof layer to the height of the upper edge of the foundation pit.

[0017] Step 9: Plant green plants in the planting soil area.

[0018] Furthermore, several vertically arranged guide pipes are installed in the original soil backfilled around the planting soil. One end of the guide pipe extends to the second gravel layer, and the other end extends above the original soil.

[0019] Furthermore, the sidewall of the guide tube is also provided with several guide holes.

[0020] Furthermore, a third gravel layer is laid on top of the second waterproof layer, and planting soil is filled on top of the third gravel layer.

[0021] Furthermore, during trench excavation, the original soil on the inner surface of the trench is tamped and leveled, and then a third waterproof layer is laid on the inner surface of the trench.

[0022] Furthermore, the first waterproof layer, the second waterproof layer, and the third waterproof layer each consist of two layers of geotextile sandwiched with one layer of geomembrane.

[0023] Furthermore, a woven layer is provided between the second crushed stone layer and the original soil filling the diversion slope. The woven layer is laid between the first and second crushed stone layers and extends to the height of the second crushed stone layer.

[0024] Furthermore, when laying the woven layer, first lay it around the edge of the opening at the lower end of the guide slope, bend the woven layer upward and support it with a baffle, then lay the second crushed stone layer, and then fill the guide slope with the original soil. When the original soil is filled to the same height as the second crushed stone layer, remove the baffle and continue to fill the original soil to form a raised original soil.

[0025] Furthermore, the guide pipes are laid outwards near the junction of the planting soil and the original soil, with the spacing between the guide pipes gradually increasing from the inside out.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The present invention adopts the method of excavating and backfilling the original soil in the greening planting area, which shortens the time required for greening planting due to the need to treat the original soil and the long desalination cycle of the original soil. There is no need to improve the original soil, which reduces the process of original soil treatment and avoids the use of chemical agents. The addition of planting soil can be used directly for greening planting, shortening the waiting time for desalination.

[0028] 2. In the construction method of the present invention, since no physical isolation barrier is formed between the greening planting area and the surrounding saline-alkali soil, the greening plants can gradually expand and grow into the surrounding original soil in the later stage of growth.

[0029] 3. In the construction method of the present invention, the setting of the diversion pipe helps surface rainwater to flow downwards preferentially, reducing the flow of water from the original soil area to the planting soil area; in addition, the setting of the diversion pipe can increase the ventilation and permeability of the original soil around the planting soil, reducing the return of underground salt vapor to the planting soil area through the original soil.

[0030] 4. In the construction method of the present invention, the setting of the first crushed stone layer and the second crushed stone layer can promote salt drainage during the rainy season and reduce salt return in the planting soil area; in addition, the present invention uses the original soil backfill as much as possible to maximize the utilization of the original soil and reduce the external accumulation of the original soil and the use of crushed stone. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the groove arrangement in this invention.

[0032] Figure 2 This is a schematic diagram of the guide slope setting in this invention.

[0033] Figure 3 This is a three-dimensional schematic diagram of the guiding slope in this invention.

[0034] Figure 4 This is a partial schematic diagram of the laying of the first waterproof layer in this invention.

[0035] Figure 5 This is a schematic diagram of the second crushed stone layer laying in this invention.

[0036] Figure 6 This is a schematic diagram of the backfilling of the original soil protrusion in this invention.

[0037] Figure 7 This is a schematic diagram of the backfilling of planting soil in this invention.

[0038] Figure 8 This is a schematic diagram of the flow guide tube arrangement in this invention.

[0039] Figure 9 This is a schematic diagram of the construction of the braided layer in this invention.

[0040] Figure 10 This is a top view schematic diagram of the flow guide tube arrangement in this invention.

[0041] Figure 11 This is a diagram showing the completed construction status of the coastal saline-alkali land greening and planting project in this invention.

[0042] In the diagram, 1 is the foundation pit; 2 is the bottom trench; 3 is the upper trench; 4 is the drainage pipe; 5 is the first gravel layer; 6 is the diversion slope; 7 is the first waterproof layer; 8 is the second gravel layer; 9 is the original soil protrusion; 10 is the diversion slope; 11 is the planting soil; 12 is the diversion pipe; 13 is the third gravel layer; 14 is the woven layer; and 15 is the baffle. Detailed Implementation

[0043] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0044] This embodiment describes a method for planting vegetation in coastal saline-alkali land, which includes the following steps:

[0045] Step 1: Excavation of the original soil in the coastal saline-alkali land, such as... Figure 1As shown, a foundation pit 1 is formed, with a lateral area larger than the area of ​​the green planting area. Wooden piles are driven into the edge of the foundation pit for slope protection. Personnel enter the bottom of the foundation pit 1 and dig a trench at the bottom. During trench excavation, the original soil on the inner surface of the trench is tamped and leveled. Water in the foundation pit is drained in a timely manner during construction, and then a third waterproof layer is laid on the inner surface of the trench. The trench has a bottom trench 2 and an upper trench 3. The side walls of the bottom trench 2 are inclined. The upper trench 3 connects to the bottom trench 2 and extends laterally outward along the upper end of the inclined surface of the bottom trench 2 to form a side wing trench. The upper trench 3 and the bottom trench 2 have the same length, and the side wing trenches on both sides of the upper trench extend laterally outward by 1-1.5m relative to the bottom trench. The third waterproof layer, as well as the subsequent first and second waterproof layers, mainly serve as a waterproof barrier. A geomembrane can be used directly, or preferably, two layers of geotextile sandwiching a layer of geomembrane can be used, with the geotextile protecting the geomembrane.

[0046] Step 2: Lay drainage pipe 4 along the length of the trench. Drainage pipe 4 is equipped with drainage holes. One end of drainage pipe 4 is connected to the salt drainage well through the drainage pipe extension. The bottom of the salt drainage well is lower than the lowest point of the drainage pipe. The salt drainage well is then connected to the municipal stormwater network through the drainage pipe.

[0047] Step 3: Lay gravel on the outside of the drain pipe 4, fill the upper groove 3 with gravel and level the upper groove 3 to form the first gravel layer 5, and keep the height of the upper end face of the drain pipe lower than the upper groove.

[0048] Step 4: Lay the original soil above the upper trench 3. A guide slope 6 is set around the side wing trench on one side of the upper trench 3, with the upper opening of the guide slope 6 larger than the lower opening, forming a funnel shape. The lower opening of the guide slope 6 receives the gravel from the side wing trench. This offsets the guide slope 6 from the bottom trench 2, increasing the evaporation path of the brine vapor and facilitating the re-condensation of salts and liquefaction of water vapor. Figure 2 and Figure 3 As shown;

[0049] Step 5: Lay the first waterproof layer 7 along the guide slope 6. The first waterproof layer 7 extends upward along the lower opening edge of the guide slope 6 and extends horizontally outward from the upper opening edge of the guide slope 6, such as... Figure 4 As shown;

[0050] Step 6: Lay crushed stone above the first waterproof layer 7 to form a second crushed stone layer 8. The thinnest thickness of the second crushed stone layer (the thinnest area of ​​the second crushed stone layer below the diversion pipe) is 8-15cm, and the thickest area is 25-30cm. The crushed stone of the second crushed stone layer 8 extends upwards along the lower edge of the opening of the diversion slope 6 to a height higher than the horizontally extending first waterproof layer 7. Figure 5 As shown.

[0051] Preferably, before laying the second crushed stone layer, a woven layer 14 can be installed between the second crushed stone layer 8 and the original soil filling the guide slope. The woven layer 14 is laid between the first and second crushed stone layers and extends to the height of the second crushed stone layer. The woven layer 14 can play a shaping role when laying the second crushed stone layer 8. The pore size of the woven layer should be smaller than the particle size of the crushed stone used in the second crushed stone layer. The woven layer can be made of materials such as polyethylene mesh, wire mesh, etc., or it can be made of natural plant materials such as hemp rope and straw. Natural materials such as straw are preferred.

[0052] When laying the woven layer 14, as Figure 9 As shown, first lay a ring around the lower edge of the opening on the guide slope, bend the woven layer 14 upward and support it with the baffle 15, which is like a wooden board, then lay the second gravel layer 8, and then fill the guide slope with the original soil. When the original soil is filled to the same height as the second gravel layer 8, remove the baffle 15 and continue to fill with the original soil to form the original soil protrusion 9.

[0053] Step 7, as follows Figure 6 As shown, the original soil is filled into the guide slope 6, and the original soil is filled to the top of the second gravel layer 8 to form the original soil protrusion 9. A guide slope 10 is formed around the side of the original soil protrusion 9. The bottom of the guide slope 10 is set close to the outer side of the guide slope 6. A second waterproof layer is laid on the original soil protrusion 9. With the second waterproof layer and the guide slope 10, the surface water flows to the side along the guide slope during the infiltration process, and the salt is discharged from the surrounding original soil. The second waterproof layer also isolates the underground salt vapor from evaporating upward and entering the planting soil to a certain extent. The original soil protrusion 9 is backfilled with the original soil excavated from the foundation pit, which reduces the accumulation of excavated original soil outside the foundation pit.

[0054] Step 8: Fill the area above the second gravel layer 8 outside the second waterproof layer with original soil, filling it to the height of the upper edge of the foundation pit 1. Then, fill the area above the second waterproof layer with planting soil 11. The planting soil 11 replaces part of the original soil for greening and planting. The planting soil 11 is filled to the height of the upper edge of the foundation pit 1. Figure 7 As shown;

[0055] Several vertically installed guide pipes 12 are also installed within the original soil backfilled around the planting soil 11. The guide pipes 12 can be installed by drilling holes directly into the original soil with a steel rod, or by inserting plastic pipes, such as UPVC or PE pipes, after drilling. Several guide holes can also be made on the side wall of the plastic pipe. One end of the guide pipe 12 extends to the second gravel layer 8, and the other end extends above the original soil. Figure 8 As shown.

[0056] The guide pipes 12 are laid outwards near the junction of the planting soil 11 and the original soil, with the spacing between the guide pipes 12 gradually increasing from the inside out. Figure 10 As shown, in this embodiment, the diameter of the guide pipe 12 is 3cm, the minimum distance between adjacent guide pipes 12 is 15-20cm, and the distance between the guide pipe closest to the edge of the planting soil and the edge of the planting soil is 5-10cm.

[0057] Preferably, a third gravel layer 13 is laid above the second waterproof layer, and the planting soil 11 is filled on top of the third gravel layer 13. The laying of the third gravel layer 13 increases the aeration of the bottom of the planting soil and prevents plant roots from penetrating the second waterproof layer. The thickness of the third gravel layer can be controlled between 5-8 cm. In this embodiment, the particle size of the gravel used in the first, second, and third gravel layers is 1.5-3 cm.

[0058] Step 9: Plant greenery in the area of ​​planting soil 11, such as... Figure 11 As shown.

[0059] During the rainy season, rainwater falls on the original soil area and the planting soil area. The rainwater infiltrates along the original soil and planting soil 11. The rainwater in the planting soil area flows outward along the second waterproof layer to the original soil area and then infiltrates through the diversion pipe 12 or the original soil. Under the action of the diversion pipe 12, most of the rainwater in the original soil area flows directly to the second gravel layer 8, and some rainwater infiltrates downward along the original soil to the second gravel layer 8. After reaching the second gravel layer 8, the rainwater flows laterally along the first waterproof layer 7. Some rainwater infiltrates into the original soil on the side along the first waterproof layer 7, and some rainwater flows along the first waterproof layer 7 to the first gravel layer 5. Finally, it is discharged through the drainage pipe 4. The rainwater carries away the salt in the original soil around the planting soil area, gradually reducing the salt content in the surrounding original soil.

[0060] During the dry season, salt rises along with water vapor. Due to the presence of the first waterproof layer 7 and the second waterproof layer at the bottom of the planting soil 11, the salt vapor is blocked from rising directly. As the salt vapor passes through the first gravel layer 5 and the second gravel layer 8, some of the salt condenses again and the water vapor liquefies and flows back. Another part rises through the first gravel layer 5 and the second gravel layer 8 into the original soil around the planting soil. The presence of the guide pipe 12 increases the ventilation in the original soil and reduces the amount of salt vapor entering the planting soil through the capillary gaps of the original soil.

[0061] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for planting vegetation on coastal saline-alkali land, comprising the following steps: Step 1: Excavate the original soil of the coastal saline-alkali land to form a foundation pit. The horizontal area of ​​the foundation pit is larger than the area of ​​the green planting area. A trench is dug at the bottom of the foundation pit. When the trench is excavated, the original soil on the inner surface of the trench is tamped and leveled. Then, a third waterproof layer is laid on the inner surface of the trench. The trench has a bottom trench and an upper trench. The side walls of the bottom trench are set at an inclination. The upper trench connects to the bottom trench and extends laterally outward along the upper end of the slope of the bottom trench to form a side wing trench. Step 2: Lay a drainage pipe along the length of the trench, the drainage pipe being provided with drainage holes; Step 3: Lay gravel outside the drain pipe, filling the upper trench with gravel to form the first gravel layer; Step 4: Lay the original soil on the top of the upper trench. Set a guide slope around the side wing trench on one side of the upper trench. The upper opening of the guide slope is larger than the lower opening. The lower opening of the guide slope receives the gravel in the side wing trench. Step 5: Lay the first waterproof layer along the guide slope. The first waterproof layer extends upward along the guide slope along the lower opening edge and extends outward in a horizontal direction from the upper opening edge of the guide slope. Step 6: Lay crushed stone above the first waterproof layer to form a second crushed stone layer. The crushed stone of the second crushed stone layer extends upward along the lower edge of the opening of the guide slope to a height higher than the first waterproof layer extending horizontally. A woven layer is also provided between the second crushed stone layer and the original soil filled in the guide slope. The woven layer is laid between the first crushed stone layer and the second crushed stone layer and extends to the height of the second crushed stone layer. Step 7: Fill the guide slope with original soil, filling it to the top of the second gravel layer and forming a soil protrusion. A guide slope is formed around the side of the soil protrusion. The bottom of the guide slope is set near the outer side of the guide slope. A second waterproof layer is laid on top of the soil protrusion. Step 8: Fill the original soil above the second crushed stone layer outside the second waterproof layer to the height of the upper edge of the foundation pit, and then fill the planting soil above the second waterproof layer. A third crushed stone layer is also laid above the second waterproof layer. The planting soil is filled to the height of the upper edge of the foundation pit. Several vertically arranged guide pipes are also set in the original soil backfilled around the planting soil. One end of the guide pipe extends to the second crushed stone layer, and the other end of the guide pipe extends to the original soil. Step 9: Plant green plants in the planting soil area.

2. The construction method for greening and planting in coastal saline-alkali land according to claim 1, characterized in that, The side wall of the guide tube is also provided with several guide holes.

3. The construction method for greening and planting in coastal saline-alkali land according to claim 1, characterized in that, The first waterproof layer, the second waterproof layer and the third waterproof layer each consist of two layers of geotextile sandwiched with one layer of geomembrane.

4. The construction method for greening and planting in coastal saline-alkali land according to claim 1, characterized in that, When laying the woven layer, first lay it around the edge of the opening at the lower end of the guide slope, bend the woven layer upward and support it with a baffle, then lay the second crushed stone layer, and then fill the guide slope with original soil. When the original soil is filled to the same height as the second crushed stone layer, remove the baffle and continue to fill with original soil to form a protrusion of original soil.

5. The construction method for greening and planting in coastal saline-alkali land according to claim 1, characterized in that, The guide pipes are laid outwards from the position where the planting soil and the original soil meet, and the spacing between the guide pipes gradually increases from the inside to the outside.

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