Design and calculation method for distributed beaded film bag pressurized compaction and reinforcement of soft soil foundation

Abstract

The invention discloses a design and calculation method of a distributed beaded film bag pressurized compaction reinforced soft soil foundation, which relates to the technical field of soft foundation reinforcement, and comprises the following steps: S1, testing physical and mechanical parameters of foundation soil; s2, a composite foundation method is selected according to the foundation bearing capacity before treatment and the foundation bearing capacity after simulation treatment to determine an integral vertical reinforcement body formed after pressurization grouting of the distributed bead-shaped film bag pressurization compaction reinforcement device, or a compaction method is selected according to the foundation bearing capacity before treatment and the foundation bearing capacity after simulation treatment; determining the compression void volume of the distributed bead-shaped film bag pressurized compaction reinforcing device after pressurized grouting; and S3, the specification model, the number, the grouting volume, the arrangement mode and the arrangement distance of the distributed bead-shaped film bag pressurization compaction reinforcing device are determined according to the method selected in the step S2. Accurate positioning, directional expansion and layered compaction of the distributed bead-shaped membrane bag pressurizing compaction reinforcing device during implantation can be effectively ensured, and disturbance of a non-reinforcing area is avoided.

Description

Technical Field

[0001] This invention relates to the field of soft soil foundation reinforcement technology, and more specifically, to a design and calculation method for compacting and reinforcing soft soil foundations using distributed beaded membrane bags. Background Technology

[0002] Soft soil is widely distributed in my country, especially concentrated in coastal and riverine areas. The "stock optimization" phase of urbanization has led to a large number of foundation reinforcement projects under complex conditions. This has placed higher demands on the protection and control of existing buildings, underground pipelines, and groundwater around the reinforcement sites, and traditional methods have significant limitations. Grouting reinforcement involves injecting grout under pressure to fill foundation pores and cement the soil. It is suitable for foundations such as sandy soil and fractured rock, and offers advantages such as small construction area and flexible construction. However, the disorderly diffusion of the grout is difficult to control, leading to uneven distribution and waste of grouting materials. The reinforcement effect in soft soil is limited and depends on geological compatibility. The material cost is relatively high, and long-term durability is affected by groundwater.

[0003] Deep mixing: This method uses machinery to force-mix cement and other curing agents with soft soil to form piles. It is suitable for soft foundation treatment such as silty soil, and is simple to construct, low in cost, and without vibration or noise. However, the pile strength is greatly affected by soil properties, requires a large site space, and is prone to uneven mixing in sand and gravel layers; the curing agent diffuses slowly, the construction period is long, the curing effect is poor in low-temperature environments, and it causes significant disturbance to the existing foundation soil.

[0004] Dynamic compaction foundation: This method uses a heavy hammer to impact the soil layer from a high height, achieving forced compaction and drainage consolidation. It is suitable for coarse-grained foundations such as gravelly soil and sandy soil, and features a large reinforcement depth (up to 10m or more), low cost, and short construction period. However, it generates significant vibration and noise, and is limited to areas with sensitive surrounding environments; soft clay is prone to forming rubbery soil, and saturated silt may liquefy; the loose surface layer requires a cushion layer, and uniformity is difficult to control.

[0005] To address the pain points of traditional technologies, such as "large disturbance, difficulty in controlling the reinforcement range, unstable quality, and large material loss," a distributed beaded membrane bag pressure extrusion reinforcement device is proposed, such as... Figure 1 , Figure 2 As shown, the distributed beaded membrane bag pressurization and compaction reinforcement device 1 consists of a string of membrane bags 2. Two to four membrane bags are interconnected to form a membrane bag unit whose grouting pressure can be controlled independently. Each membrane bag unit is controlled individually. By implanting the distributed beaded membrane bag pressurization and compaction reinforcement device 1 into the soft soil foundation, grout of corresponding pressure is injected into the membrane bag 2 at the corresponding location according to the characteristics of the stratum, thereby directional treatment and layered compaction of specific weak layers.

[0006] Therefore, for the use of distributed beaded membrane bags in soft soil foundation reinforcement, there is an urgent need for a design calculation method to achieve directional treatment, layered compaction and quality control of specific weak layers. Summary of the Invention

[0007] The purpose of this invention is to provide a design and calculation method for compacting and reinforcing soft soil foundations using distributed beaded membrane bags, in order to solve the above-mentioned problems.

[0008] To achieve the objective of this invention, the technical solution adopted is: a design and calculation method for distributed beaded membrane bag pressurization and compaction reinforcement of soft soil foundations, comprising the following steps: S1. Test the physical and mechanical parameters of the foundation soil; S2. Based on the bearing capacity of the foundation before treatment and the bearing capacity of the foundation to be treated, select the composite foundation method to determine that the membrane bags in the distributed beaded membrane bag pressurization and compaction reinforcement device can form a vertically complete structure inside the foundation soil after pressurized grouting; or based on the bearing capacity of the foundation before treatment and the bearing capacity of the foundation to be treated, select the compaction method to determine that the membrane bags in the distributed beaded membrane bag pressurization and compaction reinforcement device will expand and compact the foundation soil outside the membrane bags inside the foundation soil after pressurized grouting. S3. Determine the specifications, quantity, grouting volume, arrangement method, and arrangement spacing of the distributed beaded membrane bag pressurization and compaction reinforcement device according to the method selected in step S2.

[0009] Furthermore, the composite foundation method in step S2 includes the following steps: S21. In the distributed beaded membrane bag pressurization and compaction reinforcement device, after each membrane bag is pressurized and grouted to expand, adjacent membrane bags connect to form a vertical reinforcement body with an approximately vertical structure. Therefore, multiple membrane bags in the distributed beaded membrane bag pressurization and compaction device form a reinforced pile with an approximately circular cross-section after grouting and pressurization. The formula for calculating the equivalent pile cross-section diameter of the reinforced pile is as follows: in, The volume of each membrane bag after grouting and pressurization in the distributed beaded membrane bag pressurization and compaction reinforcement device; The thickness of the soft soil layer to be treated; S22. The formula for calculating the bearing capacity of the foundation is as follows: in, This is the single pile bearing capacity utilization factor; For area replacement rate, , Based on the planar arrangement of the distributed beaded membrane bag pressurization and compaction reinforcement device, the equivalent circle diameter of the processing area shared by one distributed beaded membrane bag pressurization and compaction reinforcement device; The characteristic value of the vertical bearing capacity of a single equivalent pile; This is the equivalent pile cross-sectional area; This is the soil bearing capacity utilization coefficient between two adjacent equivalent piles; The characteristic value of soil bearing capacity between two adjacent equivalent piles after compaction of soft foundation soil; S23. The formula for estimating the bearing capacity of a single equivalent pile is as follows: in, This is the equivalent pile perimeter; The characteristic value of the side resistance of the i-th layer of soil around the equivalent pile; The thickness of the i-th soil layer within the equivalent pile length range; The equivalent pile end resistance utilization coefficient; This represents the characteristic value of the end resistance of the equivalent pile.

[0010] Furthermore, the compaction method in step S2 includes the following steps: S21. Based on the physical and mechanical parameters in step S1 and the existing experimental data, plot the relationship curves between the bearing capacity and void ratio of the foundation soil in different regions, with different water contents and different types of foundation soil. S22. Based on the moisture content, void ratio, and soil type of the foundation soil before treatment, and according to the expected bearing capacity of the foundation after treatment, determine the maximum void ratio of the foundation soil after treatment. Then, calculate the required expansion volume of the distributed beaded membrane bag pressurization and compaction reinforcement device after treatment based on the thickness and area of ​​the treated soft soil layer. The calculation formula is as follows: in, The area of ​​soft soil foundation to be treated; The thickness of the soft soil layer to be treated; To address the void ratio of the foundation soil before treatment; The void ratio of the foundation soil after treatment.

[0011] Furthermore, the distributed beaded membrane bag pressurization and compaction reinforcement device can be arranged in square, rectangular, or quincunx shapes.

[0012] The beneficial effects of this invention are: This invention allows for the selection of a corresponding model of distributed beaded membrane bag pressurization and compaction reinforcement device based on the depth of the soil layer to be reinforced. Furthermore, the calculation method provided by this invention effectively ensures that the distributed beaded membrane bag pressurization and compaction reinforcement device is accurately positioned, directionally expanded, and compacted in layers during implantation, avoiding disturbance to the non-reinforced area and achieving high reinforcement accuracy.

[0013] In this invention, the implantation of the distributed beaded membrane bag pressure compaction reinforcement device can be adapted to different load-bearing requirements by using a composite foundation method or a compaction method. The results are quantifiable and the design is highly controllable. Attached Figure Description

[0014] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0015] Figure 1 This is a diagram showing the state of the distributed beaded membrane bag pressurization and compaction reinforcement device after it has been implanted into the foundation soil without pressurization grouting. Figure 2 This is a diagram showing the state of the distributed beaded membrane bag pressurization and compaction reinforcement device after it has been implanted into the foundation soil and pressurized with grout.

[0016] The attached diagram shows the markings and corresponding component names: 1. Distributed beaded membrane bag pressurization and compaction reinforcement device; 11. Membrane bag. Detailed Implementation

[0017] The following embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the embodiments.

[0019] When using a distributed beaded membrane bag compaction and reinforcement device to compact and reinforce soft soil foundations, part of the soil is compacted and strengthened, forming an expansion structure. After the grouting material is injected into the membrane bags of the distributed beaded membrane bag compaction and reinforcement device, the reinforcement formed by the cooperation of each membrane bag in the device, together with the foundation soil, shares the load on the artificial foundation, approximating the definition of a composite foundation. Based on different situations (considering the structural integrity of the vertical reinforcement after the expansion of the distributed beaded membrane bag grouting), the following two design and calculation methods for distributed beaded membrane bag compaction and reinforcement of soft soil foundations are proposed.

[0020] Example 1 This invention provides a design and calculation method for compacting and reinforcing soft soil foundations using distributed beaded membrane bags, comprising the following steps: S1. Test the physical and mechanical parameters of the foundation soil through geotechnical engineering investigation report or soil sampling test; S2. Based on the bearing capacity of the foundation before treatment and the bearing capacity of the foundation after treatment, the composite foundation method is selected. It is determined that after pressurization and grouting, two adjacent membrane bags in the distributed beaded membrane bag pressurization and compaction reinforcement device can form a vertical reinforcement body with an approximately complete structure inside the foundation soil. S21. In the distributed beaded membrane bag pressurization and compaction reinforcement device, after each membrane bag is pressurized and grouted to expand, adjacent membrane bags connect to form a vertical reinforcement body with an approximately vertical structure. Therefore, after grouting and pressurization, multiple membrane bags in the distributed beaded membrane bag pressurization and compaction reinforcement device form a reinforced pile with an approximately circular cross-section. The formula for calculating the equivalent pile cross-section diameter of this reinforced pile is as follows: in, The volume (m³) of each membrane bag after grouting and pressurization in the distributed beaded membrane bag pressurization and compaction reinforcement device. Thickness of soft soil layer (m); S22. The formula for calculating the bearing capacity of the foundation is as follows: in, This is the single pile bearing capacity utilization factor; For area replacement rate, , Based on the planar arrangement of the distributed beaded membrane bag pressurization and compaction reinforcement device, the equivalent circle diameter (m) of the processing area shared by one distributed beaded membrane bag pressurization and compaction reinforcement device. The characteristic value of the vertical bearing capacity of a single equivalent pile (kN); Equivalent pile cross-sectional area (㎡); This is the soil bearing capacity utilization coefficient between two adjacent equivalent piles; The characteristic value (kPa) of the soil bearing capacity between two adjacent equivalent piles after the soft foundation soil is compacted. S23. The formula for estimating the bearing capacity of a single equivalent pile is as follows: in, The equivalent pile perimeter (m); The characteristic value of the lateral resistance (kPa) of the i-th layer of soil around the equivalent pile. The thickness (m) of the i-th soil layer within the equivalent pile length range. The equivalent pile end resistance utilization coefficient; This represents the characteristic value (kPa) of the equivalent pile end resistance.

[0021] S3. Based on the composite foundation in step S2, determine the specifications, quantity, grouting volume, arrangement method, and spacing of the distributed beaded membrane bag pressurization and compaction reinforcement device. The arrangement method of the distributed beaded membrane bag pressurization and compaction reinforcement device can be square, rectangular, quincunx, etc.

[0022] The design and calculation method for distributed beaded membrane bag pressurization and compaction reinforcement of soft soil foundations provided in this embodiment is applicable to situations where the foundation bearing capacity is greatly increased and the vertical reinforcement structure remains intact after grouting and pressurization expansion of the distributed beaded membrane bag pressurization and compaction reinforcement device.

[0023] Example 2 S1. Test the physical and mechanical parameters of the foundation soil through geotechnical engineering investigation report or soil sampling test; S2. Based on the bearing capacity of the foundation before treatment and the bearing capacity of the foundation after treatment, select the compaction method, and determine that the membrane bags in the distributed beaded membrane bag pressurized compaction reinforcement device reach the compressed void volume inside the foundation soil after pressurized grouting. The compaction method includes the following steps: S21. Based on the evaluation of foundation bearing capacity, for silt, silty soil, soft soil, etc., after obtaining some basic physical parameters through testing, and based on the summary of existing test data, plot the relationship curves between the void ratio of foundation soil and foundation bearing capacity for different regions, different water contents, and different soil types. S22. Based on the moisture content, void ratio, and soil type of the foundation soil before treatment, and according to the expected bearing capacity of the foundation after treatment, determine the maximum void ratio of the foundation soil after treatment. Then, calculate the required expansion volume of the distributed beaded membrane bag pressurization and compaction reinforcement device after treatment based on the thickness and area of ​​the treated soft soil layer. The calculation formula is as follows: in, The area of ​​soft soil foundation to be treated (㎡); The thickness (m) of the soft soil layer to be treated; To address the void ratio of the foundation soil before treatment; The void ratio of the foundation soil after treatment.

[0024] S3. Based on the specifications and volume of the selected distributed beaded membrane bag pressurization and compaction reinforcement device after grouting and pressurization expansion, determine the number of distributed beaded membrane bag pressurization and compaction reinforcement devices required within the area of ​​the foundation soil to be treated, and select the arrangement form of the distributed beaded membrane bag pressurization and compaction reinforcement devices, such as: square, rectangle, quincunx. Finally, determine the arrangement spacing between two adjacent distributed beaded membrane bag pressurization and compaction reinforcement devices when implanting them.

[0025] In this embodiment, the required expansion volume of the distributed beaded membrane bag pressurization and compaction reinforcement device is determined based on the area and thickness of the soft soil foundation before and after treatment, as well as the void ratio of the foundation soil obtained from the desired foundation bearing capacity. Finally, the arrangement and quantity are determined according to the specifications of the selected distributed beaded membrane bag pressurization and compaction reinforcement device. This method only considers the increase in foundation bearing capacity achieved by the compaction of the outer foundation soil after membrane bag expansion, without considering the contribution of the grouting and consolidation body of the membrane bag in the treated foundation soil to the increase in foundation bearing capacity. The calculation results are on the safe side and are suitable for situations where the structural integrity of the vertical reinforcement body after grouting and pressurization expansion of the distributed beaded membrane bag pressurization and compaction reinforcement device is poor.

[0026] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A design and calculation method for soft soil foundation reinforcement using distributed beaded membrane bags under pressure compaction, characterized in that... Includes the following steps: S1. Test the physical and mechanical parameters of the foundation soil; S2. Based on the bearing capacity of the foundation before treatment and the bearing capacity of the foundation to be treated, select the composite foundation method to determine that the membrane bags in the distributed beaded membrane bag pressurization and compaction reinforcement device can form a vertically complete structure inside the foundation soil after pressurized grouting; or based on the bearing capacity of the foundation before treatment and the bearing capacity of the foundation to be treated, select the compaction method to determine that the membrane bags in the distributed beaded membrane bag pressurization and compaction reinforcement device will expand and compact the foundation soil outside the membrane bags inside the foundation soil after pressurized grouting. S3. Determine the specifications, quantity, grouting volume, arrangement method, and arrangement spacing of the distributed beaded membrane bag pressurization and compaction reinforcement device according to the method selected in step S2.

2. The design and calculation method for distributed beaded membrane bag pressurization and compaction reinforcement of soft soil foundation according to claim 1, characterized in that, The composite foundation method in step S2 includes the following steps: S21. In the distributed beaded membrane bag pressurization and compaction reinforcement device, after each membrane bag expands under pressure grouting, adjacent membrane bags connect to form a vertical reinforcement body with an approximately vertical structure. Therefore, after multiple vertical membrane bags in the distributed beaded membrane bag pressurization and compaction device are grouted and pressurized, they form a reinforced pile with an approximately circular cross-section. The formula for calculating the equivalent pile cross-section diameter of the reinforced pile is as follows: in, The volume of each membrane bag after grouting and pressurization in the distributed beaded membrane bag pressurization and compaction reinforcement device; The thickness of the soft soil layer to be treated; S22. The formula for calculating the bearing capacity of the foundation is as follows: in, This is the single pile bearing capacity utilization factor; For area replacement rate, , Based on the planar arrangement of the distributed beaded membrane bag pressurization and compaction reinforcement device, the equivalent circle diameter of the foundation treatment area shared by one distributed beaded membrane bag pressurization and compaction reinforcement device; The characteristic value of the vertical bearing capacity of a single equivalent pile; This is the equivalent pile cross-sectional area; This is the soil bearing capacity utilization coefficient between two adjacent equivalent piles; The characteristic value of the bearing capacity of the foundation soil between two adjacent equivalent piles after compaction of soft foundation soil; S23. The formula for estimating the bearing capacity of a single equivalent pile is as follows: in, This is the equivalent pile perimeter; The characteristic value of the side resistance of the i-th layer of soil around the equivalent pile; The thickness of the i-th soil layer within the equivalent pile length range; The equivalent pile end resistance utilization coefficient; This represents the characteristic value of the end resistance of the equivalent pile.

3. The design and calculation method for distributed beaded membrane bag pressurization and compaction reinforcement of soft soil foundation according to claim 1, characterized in that, The compaction method in step S2 includes the following steps: S21. Based on the physical and mechanical parameters in step S1 and the existing experimental data, plot the relationship curves between the bearing capacity and void ratio of the foundation soil in different regions, with different water contents and different types of foundation soil. S22. Based on the water content, void ratio, and soil type of the foundation soil before treatment, and according to the expected bearing capacity of the foundation after treatment, determine the maximum void ratio of the foundation soil after treatment. Then, calculate the required expansion volume of the distributed beaded membrane bag pressurization and compaction reinforcement device after treatment based on the thickness and area of ​​the treated soft soil layer. The calculation formula is as follows: in, The soil swelling influence coefficient is greater than 1. The area of ​​soft soil foundation to be treated; The thickness of the soft soil layer to be treated; To address the void ratio of the foundation soil before treatment; The void ratio of the foundation soil after treatment.

4. The design and calculation method for distributed beaded membrane bag pressurization and compaction reinforcement of soft soil foundation according to claim 2 or 3, characterized in that, The distributed beaded membrane bag compression and reinforcement device can be arranged in square, rectangular, or quincunx shapes.

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