Ternary solidification drainage root system flexible thick shell layer and construction method thereof

Abstract

The invention discloses a construction method of a ternary solidification drainage root system flexible thick shell layer. The construction method comprises the following steps that firstly, a deep and thick soft soil layer with a certain thickness is formed, wherein the deep and thick soft soil layer is subjected to drainage solidification through a plant fiber type drainage plate; 2, forming a shallow sludge solidification treatment layer with a certain thickness; and 3, forming a shallow vetiver root system ecological soil fixation layer with a certain thickness. According to the method, sludge soil in the deep soft foundation is quickly converted into plastic soil from fluid soil, the bearing capacity characteristic value of the formed overall stable foundation is larger than or equal to 100 Kpa or above, and the post-construction settlement value is smaller than or equal to 15 cm or below.

Description

Technical Field

[0001] This invention relates to the technical fields of soft foundation treatment, fluid soil treatment, solidified soil treatment, and soil stabilization treatment, specifically to a flexible thick shell layer and its construction method. Background Technology

[0002] The treatment of deep soft soil foundations has always been a challenge in engineering construction. Deep soft soil foundations are characterized by high compressibility and low strength. Improper treatment can easily lead to engineering accidents, and significant settlement can still occur after construction, affecting the later functional use. It also leads to huge maintenance costs. Although traditional foundation treatment methods are widely used, their limitations and human factors are becoming increasingly prominent, and they urgently need to be improved and adjusted to meet the needs of modern engineering.

[0003] Traditional methods for treating deep soft soil foundations, such as vacuum preloading, combined vacuum preloading and surcharge preloading, and deep mixing piles, are time-consuming, requiring 7-8 months or even longer, and are costly. Post-construction effects are unstable, with significant settlement, easily leading to structural deformation and cracking. Vacuum preloading requires numerous multi-layered vacuum membranes, which become waste and pollute the surrounding environment after construction. Secondly, large amounts of plastic drainage boards inserted underground do not degrade for 100 years, consuming large amounts of petrochemical raw materials and constituting a typical source of white pollution. Thirdly, vacuum preloading consumes enormous amounts of electricity, making electricity costs a major expense. Surcharge preloading requires transporting large quantities of quarried rock to the site for surcharge, which is time-consuming and labor-intensive, causing repeated environmental pollution, and has a long overall construction period with unsatisfactory treatment results. The fundamental reason why these methods are ineffective is that water in the deep soft soil foundation is not properly removed. Even after post-construction excavation or core extraction, dripping or fluid-plastic silt is still found. Excessive pressure during deep mixing piles damages the original silt structure. The use of excessive water and incompatible cement during mixing results in a large number of lumpy silt-encased soil and lumpy cement-containing soil. Water, cement, and soil do not interact with each other and are independent of each other. Even with the continuous increase in cement content, the treatment effect is still unsatisfactory.

[0004] Given the drawbacks and limitations of the aforementioned methods for treating deep soft soil foundations, it is necessary to improve and innovate new methods. Summary of the Invention

[0005] The purpose of this invention is to provide a ternary solidified drainage root system flexible thick shell layer and its construction method for rapidly transforming silt in deep soft foundations from fluid soil to plastic soil, forming an integral stable foundation with a bearing capacity characteristic value greater than or equal to 100 kPa and a post-construction settlement value less than or equal to 15 cm.

[0006] The technical solution of this invention is: A three-element solidified drainage root system flexible thick shell layer is characterized by: including a silt layer, a plant fiber drainage board inserted into the silt layer, and the plant fiber drainage board penetrating the silt layer to a stable soil layer; the upper part of the silt layer is a silt solidification treatment layer formed by mixing inorganic high-curing agent with soft silt soil; vetiver seedlings are implanted in the silt solidification treatment layer to form a shallow vetiver root system ecological soil stabilization layer of a certain thickness.

[0007] The thickness of the sludge solidification treatment layer is 20%-30% of the total sludge treatment thickness, and the thickness is not less than 2.5m.

[0008] The plant fiber drainage board is a biodegradable plant fiber drainage board with a width of 5cm-100cm and a thickness of 4-4.5mm.

[0009] A construction method for a ternary solidification drainage root system flexible thick shell layer, characterized by comprising the following steps in sequence: Step 1: Forming a deep soft soil layer with a certain thickness of plant fiber drainage board for drainage consolidation: Insert the plant fiber drainage board, which penetrates through the silt layer to the stable soil layer, and the free water in the silt is allowed to drain freely to the ground along the longitudinal channel of the drainage board. Step 2: Forming a shallow silt solidification treatment layer of a certain thickness: The thickness of the silt solidification treatment layer is 20%-30% of the total silt treatment thickness, and the thickness is not less than 2.5m; the silt solidification treatment layer is obtained by mixing an inorganic high-curing agent with soft silt soil, mechanically stirring for a time of not less than 3 minutes to ensure that the curing agent and the foundation soil are fully and evenly mixed; the amount of inorganic high-curing agent used is 5%-15% of the dry volume of silt, and the resulting shallow silt solidification treatment layer is a flexible solidified thick shell layer with a certain rigidity and compressive strength. Step 3: Forming a shallow vetiver root ecological soil stabilization layer of a certain thickness: After the shallow silt solidification treatment layer is formed, vetiver seedlings are planted 5-10cm into the soil, with 15-25cm exposed above the soil surface, and the seedlings are spaced 40-50cm apart. After 10 days, the roots of the vetiver seedlings begin to build a shallow vetiver root network "living steel bar" soil stabilization system. The roots can firmly wrap and fix the solidified soil, which greatly improves the rigidity, foundation bearing capacity, shear resistance, crack resistance and erosion resistance of the shallow silt solidification treatment layer.

[0010] The above-mentioned construction method for the ternary solidified drainage root flexible thick shell layer has a total construction period of 2.5-3.5 months. The resulting ternary state deep soft soil thick shell layer works together to ensure that the treated soil is complete and stable. The characteristic value of the foundation bearing capacity after construction is greater than or equal to 100 kPa and the settlement value after construction is less than or equal to 15 cm.

[0011] The inorganic high-curing agent is the "Ronggong Boda" RG series of high-efficiency cementitious materials, which performs best in the curing treatment of various types of silt and fluid silt soil under conditions of moisture content of 80%-150% and organic matter content of 15%.

[0012] The plant fiber drainage board is a biodegradable plant fiber drainage board with a width of 5cm-100cm and a thickness of 4-4.5mm. After being planted in the soil for 2 years, the plant fiber chains begin to decompose and gradually degrade.

[0013] The construction method of the ternary solidification and drainage root-based flexible thick shell layer of this invention utilizes a synergistic "solidification-drainage-soil stabilization" ternary approach to rapidly transform silt in deep soft soil foundations into a stable, integral foundation with a bearing capacity characteristic value greater than or equal to 100 kPa and a post-construction settlement value less than or equal to 15 cm. In this patented ternary synergistic method, the shallow layer is a shallow silt solidification treatment layer of a certain thickness, while the deep layer consists of a plant fiber drainage board, an active drainage layer based on geodynamic forces, and a vetiver root-based ecological soil stabilization layer. The shallow vetiver mesh-like reinforced concrete layer stabilizes the soil, resists cracking, and improves the overall rigidity of the solidified soil. The total construction period is 2.5-3 months, saving owners over 30% in costs. This method achieves rapid consolidation and long-term stability of soft soil foundation treatment, making it particularly suitable for high-speed rail projects, ports, wharves, tidal flats, airports, petrochemical bases, and other scenarios with strict time constraints.

[0014] This invention presents a construction method for a ternary solidified drainage root system flexible thick shell layer, which features a shorter construction period and lower cost, significantly solving the problem of post-construction settlement. It overcomes the difficulties of traditional methods, such as long construction periods, high costs, and unstable results, and further ensures the quality and safety of deep soft soil foundation projects, meeting the needs of modern engineering construction.

[0015] In forming the ternary solidified drainage root system flexible thick shell layer, this invention does not set up a sand permeable layer of plant fiber drainage board, a vacuum pre-compression membrane, or a vacuum pre-compression drainage system. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a schematic diagram of a ternary solidified drainage root system flexible thick shell structure according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the vetiver root network formed by the present invention.

[0019] In the picture: 1. Deep silt layer; 2. Plant fiber drainage board; 3. Vetiver root ecological soil stabilization layer; 4. Shallow silt solidification treatment layer; 5. Vetiver. Detailed Implementation

[0020] I. Construction of Deep Plant-Based Fiber Biodegradable Drainage Board a. According to the design requirements, select plant fiber drainage boards 3 with high strength, corrosion resistance, drainage porosity and water conductivity that meet the design requirements. The boards are 5-10cm wide, 4-4.5mm thick, and 0.8-1.2m apart. Use a board inserter to vertically insert the plant fiber drainage boards 2 into the deep soft soil and penetrate through the deep soft silt layer 1 to the stable soil layer.

[0021] b. By utilizing the rough surface of the plant fiber drainage board, the tension structure within the natural drainage channels, and the capillary action of the fiber mesh structure on the board surface, free water in deep soft soil can be actively drained upwards to the ground through multiple drainage channels in the inner core of the plant fiber drainage board under the action of gravity. This improves the consolidation of the deep soft soil, ultimately meeting the design and usage requirements, thereby enhancing the overall bearing capacity and resistance to settlement and cracking of the deep soft soil.

[0022] c. Using plant fiber drainage boards to treat free water in deep soft silt eliminates the need for vacuum preloading plastic film covering, large amounts of electricity for vacuum preloading, and a 30-50cm thick permeable sand layer on the surface, thus greatly saving costs and shortening the construction period.

[0023] d. The bearing capacity of the resulting deep soft soil ternary solidified drainage root system flexible thick shell foundation is greater than or equal to 100 kPa, and the post-construction settlement value is less than or equal to 15 cm.

[0024] II. Construction of Shallow Silt Solidification Treatment Layer a. The thickness of the shallow silt solidification treatment layer 4 is 20-30% of the total thickness of the deep soft silt treated, and the thickness is not less than 2.5m.

[0025] b. The shallow sludge solidification layer 4 is obtained by thoroughly mixing the inorganic high-curing-point agent with soft sludge in a dry or wet mixture. The amount of inorganic high-curing-point agent used is between 5% and 15% of the dry sludge volume. The resulting sludge solidification treatment flexible thick shell layer has a certain rigidity. The inorganic high-curing-point agent is "Ronggong Boda" RG series high-efficiency cementitious material (e.g., "Ronggong Boda" RG-3, RG-2, or RG-1). c. "Ronggong Boda" RG series high-efficiency cementitious materials are particularly suitable for the solidification treatment of various types of silt and fluidized silt with a moisture content between 80% and 150% and an organic matter content below 20%. The lateral pressure-free strength reaches 0.5-0.8 MKa after 7 days and 1.2-1.5 MKa after 28 days.

[0026] 3. Construction of the ecological soil stabilization layer using vetiver grass mesh-like rebar and root system a. Seven days after the completion of the shallow silt solidification treatment layer 4, vetiver seedlings can be planted on it. The seedlings should be planted 5-10cm deep, with 20-30cm exposed above the soil, and spaced 30-50cm apart. The roots of the vetiver will begin to grow and multiply rapidly after 10 days, and after 30 days, the root system will reach over 100cm in length. (Details...) Figure 2 .

[0027] b. Utilize the extensive root system of vetiver to stabilize the soil. Mature vetiver has 5 rootlets that can reach 2.5-8m in length, and the tensile strength of a single vetiver root cross section is 75MKa.

[0028] c. As the vetiver roots continue to grow and split, they intertwine and wrap with the shallow silt solidification treatment layer 4, forming a mesh-like living steel structure ecological soil stabilization system layer. This makes the shallow silt solidification treatment layer 4 denser, stronger, and more resistant to shearing, erosion, and cracking. The characteristic value of the bearing capacity of its ternary solidified drainage root system flexible thick shell foundation reaches greater than or equal to 100Kpa and the post-construction settlement value is less than or equal to 15cm.

[0029] The resulting ternary solidified drainage root system flexible thick shell layer is characterized by: including a silt layer, a plant fiber drainage board inserted into the silt layer, and the plant fiber drainage board penetrating the silt layer to the stable soil layer; the upper part of the silt layer is a silt solidification treatment layer formed by mixing inorganic high-curing agent with soft silt soil; vetiver seedlings are implanted in the silt solidification treatment layer to form a shallow vetiver root system ecological soil stabilization layer of a certain thickness.

Claims

1. A ternary solidified drainage root system flexible thick shell layer, characterized in that: The system includes a silt layer, a plant fiber drainage board inserted into the silt layer, and the plant fiber drainage board penetrating the silt layer to the stabilized soil layer; the upper part of the silt layer is a silt solidification treatment layer formed by mixing inorganic high-curing agent with soft silt soil; vetiver seedlings are planted in the silt solidification treatment layer to form a shallow vetiver root ecological soil stabilization layer of a certain thickness.

2. The ternary solidified drainage root system flexible thick shell layer according to claim 1, characterized in that: The thickness of the sludge solidification treatment layer is 20%-30% of the total sludge treatment thickness, and the thickness is not less than 2.5m.

3. A ternary solidified drainage root system flexible thick shell layer according to claim 1 or 2, characterized in that: The plant fiber drainage board is a biodegradable plant fiber drainage board with a width of 5cm-100cm and a thickness of 4-4.5mm.

4. A construction method for a ternary solidification drainage root system flexible thick shell layer, characterized in that, The steps are as follows: Step 1: Forming a deep soft soil layer with a certain thickness of plant fiber drainage board for drainage consolidation: Insert the plant fiber drainage board, which penetrates through the silt layer to the stable soil layer, and the free water in the silt is allowed to drain freely to the ground along the longitudinal channel of the drainage board. Step 2: Forming a shallow silt solidification treatment layer of a certain thickness: The thickness of the silt solidification treatment layer is 20%-30% of the total silt treatment thickness, and the thickness is not less than 2.5m; the silt solidification treatment layer is obtained by mixing an inorganic high-curing agent with soft silt soil, mechanically stirring for a time of not less than 3 minutes to ensure that the curing agent and the foundation soil are fully and evenly mixed; the amount of inorganic high-curing agent used is 5%-15% of the dry volume of silt, and the resulting shallow silt solidification treatment layer is a flexible solidified thick shell layer with a certain rigidity and compressive strength. Step 3: Forming a shallow vetiver root ecological soil stabilization layer of a certain thickness: After the shallow silt solidification treatment layer is formed, vetiver seedlings are planted 5-10cm into the soil, with 15-25cm exposed above the soil surface, and the seedlings are spaced 40-50cm apart. After 10 days, the roots of the vetiver seedlings begin to build a shallow vetiver root network "living steel bar" soil stabilization system, and their roots can firmly wrap and fix the solidified soil.

5. The construction method of the ternary solidified drainage root system flexible thick shell layer according to claim 4, characterized in that, The inorganic high-curing agent is "Ronggong Boda" RG series high-efficiency cementitious material.

6. The construction method of the ternary solidified drainage root system flexible thick shell layer according to claim 4, characterized in that, The plant fiber drainage board is a biodegradable plant fiber drainage board with a width of 5cm-100cm and a thickness of 4-4.5mm. After being planted in the soil for 2 years, the plant fiber chains begin to decompose and gradually degrade.

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