A method for in-situ solidification of riverbed sediment to achieve riverbank greening and slope protection

Abstract

This invention relates to a method for in-situ solidification of riverbed sediment to achieve greening and slope protection of riverbanks. The method involves excavating riverbed sediment and analyzing soil samples. Inorganic cementitious materials are added to the riverbed sediment and mixed to form a solidified soil mixture. Materials for controlling the drying and temperature shrinkage of the inorganic cementitious materials, adjusting the pH value of the solidified soil, and promoting plant growth are added to the solidified soil mixture and mixed again. Plant seeds are then added to the solidified soil mixture to form a greening solidified soil mixture. This greening solidified soil mixture is then applied to the riverbank using spraying or formwork casting to form a greening riverbank slope protection structure. The advantages of this invention are: in-situ utilization of riverbed sediment while simultaneously forming a greening riverbank slope protection. This method solves the problems of transporting and disposing of riverbed sediment and achieves ecological treatment of riverbank slope protection, ultimately achieving ecological balance.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and in particular to a method for in-situ solidification of riverbed sediment to achieve greening and slope protection of riverbanks. Background Technology

[0002] Many rivers in my country carry significant sediment loads, requiring substantial annual investment of manpower and resources for river dredging and slope reinforcement, amounting to hundreds of billions of yuan. Currently, river dredging primarily employs mechanical excavation, followed by the removal and backfilling of the riverbed sediment. Traditional river slope reinforcement methods mainly utilize crushed stone and concrete masonry. However, these traditional methods require large quantities of cement and building stone, resources that are gradually dwindling, severely impacting the ecological balance.

[0003] Currently, there are three main problems in the process of river dredging and riverbank slope reinforcement: 1) Riverbed sediment needs to be cleaned and transported away, but cities are increasingly lacking space for landfilling this sediment; 2) Traditional bank reinforcement requires a large amount of gravel and cement, resulting in more carbon emissions and ecological damage. At the same time, concrete slope protection will also have adverse effects on the environment and cause ecological degradation; 3) Riverbank reinforcement needs to be in line with urban environmental protection and achieve ecological balance.

[0004] Therefore, based on ecological principles, ensuring the safety of river flood control, comprehensively utilizing the natural storage, infiltration, and purification functions of urban rivers, while simultaneously benefiting water conservation, sustainable ecological development, enhanced flood control and drainage capacity, accelerated river management, and protection of the river environment, has become a key technical issue for riverbank protection. Thus, a new method for riverbank protection is urgently needed to address the current predicament. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a method for in-situ solidification of riverbed sediment to achieve greening and slope protection of riverbanks. This method involves solidifying the dredged riverbed sediment in situ to reinforce the riverbanks and form a greening slope, which aligns with urban environmental protection and achieves ecological balance in the river. At the same time, planting greenery in the solidified soil not only achieves ecological protection but also utilizes the root system of the plants to improve the erosion resistance of the solidified soil.

[0006] The objective of this invention is achieved through the following technical solutions:

[0007] A method for in-situ solidification of riverbed sediment to achieve riverbank greening and slope protection, characterized in that the method includes the following steps:

[0008] The riverbed sediment was excavated and soil samples were analyzed to obtain the water content of the riverbed sediment and determine its properties.

[0009] The moisture content of the riverbed sediment is adjusted to a suitable level based on the measured properties of the sediment.

[0010] Inorganic cementitious material is added to the riverbed sediment and mixed to form a solidified soil mixture. The inorganic cementitious material is composed of cement, fly ash, and quicklime.

[0011] Add a material for controlling the dry thermal shrinkage of the inorganic cementitious material, as well as a material for adjusting the pH value of the solidified soil and promoting plant growth to the solidified soil mixture, and then mix them together.

[0012] Plant seeds are added to the solidified soil mixture to form a green plant solidified soil mixture.

[0013] The green plant-stabilized soil mixture is applied to the riverbank using spraying or formwork casting to form a green plant-type riverbank slope protection structure.

[0014] When the riverbed sediment is silt, its moisture content is adjusted to 40%-60%; when the riverbed sediment is silty clay, its moisture content is adjusted to 45%-70%; when the riverbed sediment is clay, its moisture content is adjusted to 55%-80%.

[0015] The moisture content of the riverbed sediment is adjusted to a suitable level by means of drying or adding water, based on its properties and the current moisture content.

[0016] The mass ratio of the inorganic cementitious material to the riverbed sediment is 0.05-0.5:1.

[0017] The mass ratio of the cement, the fly ash, and the quicklime is 1:0.1-0.3:0.1-0.3.

[0018] The amount of the dry thermal shrinkage material is 0.2%-2% of the amount of the inorganic cementitious material; it includes silicon dioxide, aluminum oxide, calcium oxide, potassium chloride, potassium sulfate, aluminum sulfate, sodium chloride, calcium chloride, and magnesium sulfate, and the mass ratio of each material is 5-9:10-16:1-3:6-10:4-7:20-30:5-9:8-12:15-25.

[0019] The amount of the material used to adjust the pH value of the solidified soil and promote plant growth is 0.1%-1% of the amount of the inorganic cementitious material; it includes citric acid and carbamide, and the mass ratio of the two is 20-40:60-80.

[0020] The plant seeds are one or a combination of two or more of the following: goosegrass, alfalfa, crested wheatgrass, foxtail grass, and kudzu vine; the amount of plant seeds added is 0.01-0.1 kg per cubic meter of solidified soil mixture.

[0021] The green-planted riverbank slope protection structure includes an ecological slope top pavement, a slope structure, and a toe protection structure. The ecological slope top pavement is located at the top of the riverbank slope, the slope structure covers the riverbank slope, and the toe protection structure is located at the bottom of the slope structure.

[0022] The slope structure adopts a rapid drainage waist structure, which is based on the steepest descent curve that follows the equation of the steepest descent curve; the foot protection structure adopts a biomimetic structure, which is a fish scale-like structure set along the direction of water flow.

[0023] The advantages of the present invention are:

[0024] 1) Riverbed sediment can be utilized on-site, while simultaneously forming green riverbank revetments. This method not only solves the problem of transporting and disposing of riverbed sediment, but also achieves ecological treatment of riverbank revetments, ultimately achieving ecological balance.

[0025] 2) The developed green plant-type solidification material can increase the strength and resistance to drying and temperature shrinkage of solidified soil, while also promoting plant growth and using the root system of plants to reinforce the solidified soil.

[0026] 3) The designed ecological slope protection structure uses the steepest descent curve as its waist, which can quickly drain rainwater and increase the safety of the slope protection. In addition, the toe protection adopts a biomimetic structure that resembles a fish body, which can significantly reduce water flow resistance, increase the toe protection's erosion resistance, and enhance the river's flood control and disaster relief capabilities. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating the principle of the method of the present invention;

[0028] Figure 2 This is a schematic diagram of the slope protection structure in this invention;

[0029] Figure 3 This is a schematic diagram of the arrangement of the shear holes in this invention. Detailed Implementation

[0030] The following examples further illustrate the features and other related characteristics of the present invention in detail, to facilitate understanding by those skilled in the art:

[0031] like Figure 1-3 As shown in the figure, labels 1-6 represent: 1. Ecological slope top pavement, 2. Shear-resistant structure, 3. Longitudinal joint, 4. Rapid drainage waist structure, 5. Bionic foot protection structure, and 6. Shear-resistant hole.

[0032] Example: Figure 1As shown in this embodiment, the method of solidifying riverbed sediment in situ to achieve green slope protection of riverbanks involves solidifying the dredged riverbed sediment in situ to reinforce the riverbank and form a green slope protection. This solves three problems: first, it addresses the problem of treating riverbed sediment in the river; second, it addresses the problem of protecting and reinforcing riverbank slopes; and third, it achieves ecological balance and protection of the riverbanks.

[0033] Specifically, the method in this embodiment includes the following steps:

[0034] 1) Excavate the riverbed sediment using excavation equipment, analyze the excavated riverbed sediment to obtain the water content of the riverbed sediment, and determine the nature of the riverbed sediment, such as silt, silty clay or clay, by referring to the "Code for Design of Building Foundations" GB 50007-2011.

[0035] 2) Based on the measured moisture content of the riverbed sediment, adjust the sediment to a suitable moisture content by sun-drying or adding water. The suitable moisture content ranges for different riverbed sediment properties are: 40%-60% for silt, 45%-70% for silty clay, and 55%-80% for clay. Analyzing the moisture content and properties of the riverbed sediment improves the performance of the subsequently processed solidified soil mixture, especially its slope protection properties.

[0036] 3) The inorganic cementitious material is mixed with riverbed sediment using a mixing device to form a solidified soil mixture. The mass ratio of the inorganic cementitious material to the riverbed sediment is 0.05-0.5:1. Its main components are cement, fly ash, and quicklime. The mass ratio of the inorganic cementitious material is cement:fly ash:furnace ash 1:0.1-0.3:0.1-0.3. The mixing time between the inorganic cementitious material and the riverbed sediment is 3-5 minutes. By mixing the inorganic cementitious material with the riverbed sediment, it is cemented and solidified to achieve a certain strength.

[0037] 4) Add a dry shrinkage control material to the inorganic cementitious material, at a dosage of 0.2%-2% of the inorganic cementitious material. This dry shrinkage control material consists of silica, aluminum oxide, calcium oxide, potassium chloride, potassium sulfate, aluminum sulfate, sodium chloride, calcium chloride, and magnesium sulfate, with a mass ratio of 5-9:10-16:1-3:6-10:4-7:20-30:5-9:8-12:15-25. Premix this material with the inorganic cementitious material for 2-3 minutes. Adding this dry shrinkage control material gives the solidified soil mixture resistance to dry shrinkage, effectively improving its performance.

[0038] 5) Add materials to adjust the pH value of the stabilized soil and promote plant growth. The amount of these materials is 0.1%-1% of the amount of inorganic cementitious materials. These materials consist of citric acid and carboxamide, with a mass ratio of 20-40:60-80. Mix this material with water at a ratio of 1:10 for 2 minutes, then add it to the stabilized soil mixture to promote plant growth and utilize the plant roots to reinforce the stabilized soil.

[0039] 6) Select one or more plant seeds and add them to the solidified soil mixture formed in step 3) to form a green plant-stabilized soil mixture. Preferred plant seeds include those with well-developed root systems such as goosegrass, alfalfa, crested wheatgrass, foxtail grass, and kudzu, to enhance the soil-stabilizing effect of the plant roots. The dosage of plant seeds is 0.01-0.1 kg per cubic meter of mixture, and the mixing time is 0.5-1 min. By controlling the dosage of plant seeds and combining this with the mixing process, the entire solidified soil area can be reinforced by plant roots, improving the soil's resistance to erosion.

[0040] 7) The resulting green plant-stabilized soil mixture is sprayed or poured using formwork to form a green plant-type riverbank slope protection structure on the riverbank.

[0041] like Figure 2 and Figure 3 As shown, the green riverbank slope protection structure in this embodiment includes an ecological slope top pavement 1, a shear-resistant structure 2, a longitudinal joint 3, a rapid drainage waist structure 4, and a biomimetic foot protection structure 5.

[0042] Among them, the ecological slope top road 1 is set at the top of the riverbank slope and can be used as a pedestrian walkway.

[0043] The shear-resistant structure 2 is created on the surface of the riverbank slope before the construction of the vegetation-stabilized soil mixture. This shear-resistant structure 2 consists of shear holes 6 arranged in a staggered pattern. Each shear hole 6 is circular, with a diameter of 5-10 cm, a spacing of 50-80 cm, and a depth of 5-6 cm. When the vegetation-stabilized soil mixture is applied to the riverbank slope surface via spraying or slab pouring, it enters each shear hole 6, forming an embedded connection. After further solidification, small shear columns are formed within each shear hole 6, thus creating a shear-resistant structure between the riverbank slope and the vegetation-stabilized soil mixture, improving their overall integrity and stability.

[0044] The main structure of the slope adopts a rapid drainage waist structure 4, which is based on the steepest descent curve and follows the equation of the steepest descent curve, enabling rainwater to drain out as quickly as possible. The slope structure is constructed in sections, with longitudinal joints 3 set between adjacent sections. Each longitudinal joint is 1-2 cm wide, and the distance between longitudinal joints is 500-800 cm to allow space for the later strain of the solidified vegetation-stabilized soil mixture.

[0045] A biomimetic foot protection structure 5 is installed at the bottom of the slope protection structure. This biomimetic foot protection structure 5 is a fish scale-like structure arranged along the water flow direction. The left and right arc-shaped scale-like structures of the fish scale structure are spaced 5cm apart, and the front and back are spaced 5cm apart, in order to reduce water flow resistance and facilitate the flow of water in the river. This can significantly reduce water flow resistance, increase the erosion resistance of the foot protection structure, and increase the flood control and flood prevention capabilities of the river. In some cases, it can also prevent the river water from stagnating to a certain extent. In addition, the combined use of the biomimetic foot protection structure 5 and the rapid drainage waist structure 4 allows rainwater to flow into the river water at the fastest speed and further flow with the river water, preventing rainwater from stagnating in the slope protection structure formed by the green vegetation and soil mixture, which would lead to a decline in the performance of the slope protection structure or even structural instability.

[0046] Although the above embodiments have been described in detail with reference to the concept and embodiments of the present invention, 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 in-situ solidification of riverbed sediment to achieve riverbank greening and slope protection, characterized in that: The method includes the following steps: The riverbed sediment was excavated and soil samples were analyzed to obtain the water content of the riverbed sediment and at the same time determine the properties of the riverbed sediment, identifying it as silt, silty clay, or clay. The moisture content of the riverbed sediment is adjusted to a suitable level based on the measured properties of the sediment. Inorganic cementitious material is added to the riverbed sediment and mixed to form a solidified soil mixture. The mass ratio of the inorganic cementitious material to the riverbed sediment is 0.05-0.5:

1. The inorganic cementitious material is composed of cement, fly ash, and quicklime, and the mass ratio of the cement, fly ash, and quicklime is 1:0.1-0.3:0.1-0.

3. A material for controlling the dry shrinkage of the inorganic cementitious material and a material for adjusting the pH value of the solidified soil mixture and promoting plant growth are added to the solidified soil mixture and then mixed. The amount of the dry shrinkage material is 0.2%-2% of the amount of the inorganic cementitious material. It includes silicon dioxide, aluminum oxide, calcium oxide, potassium chloride, potassium sulfate, aluminum sulfate, sodium chloride, calcium chloride, and magnesium sulfate, and the mass ratio of each material is 5-9:10-16:1-3:6-10:4-7:20-30:5-9:8-12:15-25. Plant seeds are added to the solidified soil mixture to form a green plant solidified soil mixture; the pH value of the solidified soil mixture and the amount of the plant growth promoting material are adjusted to 0.1%-1% of the amount of the inorganic cementitious material; the inorganic cementitious material includes citric acid and carbamide, and the mass ratio of citric acid to carbamide is 20-40:60-80; The green plant-stabilized soil mixture is applied to the riverbank by spraying or casting to form a green plant-type riverbank slope protection structure. The green-planted riverbank slope protection structure includes an ecological slope top pavement, a slope structure, a shear-resistant structure, and a toe protection structure. The ecological slope top pavement is located at the top of the riverbank slope, the slope structure covers the riverbank slope, and the toe protection structure is located at the bottom of the slope structure. The slope structure adopts a rapid drainage waist structure, which is based on the steepest descent curve that follows the equation of the steepest descent curve; the foot protection structure adopts a biomimetic structure, which is a fish scale-like structure set along the direction of water flow. Before the construction of the vegetation-stabilized soil mixture, a shear-resistant structure is created on the surface of the riverbank slope. This shear-resistant structure consists of shear holes arranged in a staggered pattern. Each shear hole is circular, with a diameter of 5-10 cm, a spacing of 50-80 cm, and a depth of 5-6 cm. When the vegetation-stabilized soil mixture is applied to the surface of the riverbank slope through spraying or slab pouring, the vegetation-stabilized soil mixture can enter into each shear hole to form an embedded connection. After the vegetation-stabilized soil mixture further solidifies, small shear columns are formed in each shear hole.

2. The method for in-situ solidification of riverbed sediment to achieve riverbank greening and slope protection according to claim 1, characterized in that: When the riverbed sediment is silt, its moisture content is adjusted to 40%-60%; when the riverbed sediment is silty clay, its moisture content is adjusted to 45%-70%; when the riverbed sediment is clay, its moisture content is adjusted to 55%-80%.

3. The method for in-situ solidification of riverbed sediment to achieve riverbank greening and slope protection according to claim 1, characterized in that: The adjustment of the moisture content of the riverbed sediment is based on the properties of the riverbed sediment and the current moisture content, and is achieved by drying or adding water to adjust it to a suitable moisture content.

4. The method for in-situ solidification of riverbed sediment to achieve riverbank greening and slope protection according to claim 1, characterized in that: The plant seeds are one or more of the following: goosegrass, alfalfa, crested wheatgrass, foxtail grass, and kudzu vine; the amount of plant seeds added is 0.01-0.1 kg per cubic meter of solidified soil mixture.

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