Method for water injection and humidification of collapsible loess strata

Abstract

The present application belongs to the technical field of civil engineering, and discloses a collapsible loess stratum water injection humidification method, which comprises the following steps: arranging a sand well in a humidification area, arranging a multilayer water delivery pipeline along the axis of the sand well, each layer of the water delivery pipeline comprising a plurality of water delivery branch pipes arranged around the sand well, and the water inlet of each water delivery branch pipe being in communication with the sand well; arranging a ridge around the wellhead of the sand well, and arranging a slope to the wellhead via the ridge; determining the natural water content and volume of the soil in the humidification area, determining the total water injection amount according to the target water content, the natural water content and the volume; injecting water into the ridge at a preset water injection rate until the total water injection amount is reached, and the water in the ridge enters the loess in the humidification area via the well wall of the sand well and the water outlet of the water delivery branch pipe. The collapsible loess stratum water injection humidification method relies on the water distribution structure of the sand well and the multilayer water delivery branch pipes around the sand well, and combines the ridge slope water guide at the wellhead to realize uniform humidification of the loess stratum and effectively eliminate the collapsibility of the loess stratum.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering technology, and specifically discloses a method for injecting water to increase humidity in collapsible loess strata. Background Technology

[0002] Collapsible loess refers to soil that undergoes significant additional deformation due to structural damage after immersion in water, under the stress of the overlying soil layer or under the combined stress of its own weight and additional stress. It is a special type of soil.

[0003] Collapsible loess generally has high strength and low compressibility when it is not wetted. However, when it is wetted, its structure rapidly deteriorates, its strength decreases, and its compressibility increases, thus exhibiting significant collapsibility. This leads to additional settlement and poses a serious threat to the safety and stability of buildings. Therefore, when carrying out engineering construction in areas with collapsible loess, the characteristics of collapsible loess should be fully considered, and moistening measures should be taken for foundation treatment to ensure the safety and stability of the project.

[0004] For moistening collapsible loess, commonly used engineering methods include pre-soaking and water injection. Pre-soaking is suitable for sites with thick layers of collapsible loess and significant self-weight subsidence. However, this method requires a large amount of water and has a long construction period. Traditional water injection methods are haphazardly arranged, resulting in uneven water injection and causing some areas to have greater subsidence than others. This uneven subsidence can introduce additional stress and deformation into the engineering structure. Summary of the Invention

[0005] The purpose of this invention is to provide a water injection and humidification method for collapsible loess strata, so as to solve the technical problem of uneven water injection in existing water injection and humidification methods, which leads to additional stress and deformation of engineering structures.

[0006] This invention provides a method for increasing the moisture content of collapsible loess strata by injecting water, comprising:

[0007] Step 1: Install sand wells in the humidification area and set up multiple layers of water supply pipelines along the axis of the sand wells. Each layer of water supply pipelines includes multiple water supply branch pipes arranged around the sand wells, and the inlet of each water supply branch pipe is connected to the sand wells.

[0008] Step 2: Lay a ground ridge around the wellhead of the sand well, and set up a slope from the ground ridge to the wellhead;

[0009] Step 3: Determine the natural moisture content and volume of the soil in the humidification area, and determine the total water injection volume based on the target moisture content, the natural moisture content, and the volume;

[0010] Step 4: Inject water into the ridge at a preset water injection rate until the total water injection volume is reached. The water in the ridge enters the loess in the humidification area through the well wall of the sand well and the outlet of the water delivery branch pipe.

[0011] Preferably, the total injection volume is determined based on the target moisture content, the natural moisture content, and the volume, specifically as follows:

[0012] The mass of the soil is determined based on the volume and average density of the soil within the humidification area;

[0013] The water shortage is determined based on the difference between the target moisture content and the natural moisture content;

[0014] Determine the water loss coefficient, and determine the total injection volume based on the product of the mass, the water shortage, and the water loss coefficient.

[0015] Preferably, sand wells are installed in the humidification area, specifically:

[0016] Drill holes in the humidification area and install perforated pipes in the drilled holes;

[0017] Sand particles are filled into the flower tube to form a sand well, wherein the particle size of the sand particles gradually decreases from the wellhead to the bottom of the sand well.

[0018] Preferably, the particle size of the sand is 0.25mm to 2mm.

[0019] Preferably, each layer of water supply pipeline includes multiple water supply branch pipes arranged around the sand well, specifically:

[0020] Each layer of water supply pipeline includes multiple water supply branch pipes of different lengths that are arranged around the sand well, and each water supply branch pipe is arranged horizontally.

[0021] Preferably, each layer of water supply pipeline includes multiple water supply branch pipes of different lengths arranged around the sand well, specifically:

[0022] Each layer of water supply pipeline includes multiple first water supply branch pipes with a first length and multiple second water supply branch pipes with a second length, wherein the first water supply branch pipes and the second water supply branch pipes are arranged around the sand well and adjacent to each other.

[0023] Preferably, the first length is equal to 1 / 3 of the length from the well wall of the sand well to the outer boundary of the humidification zone;

[0024] The second length is equal to 2 / 3 of the length from the well wall of the sand well to the outer boundary of the humidification zone.

[0025] Preferably, the lengths of the water supply branch pipes in two adjacent layers of water supply pipelines located on the same vertical line are different.

[0026] The water injection and humidification method for collapsible loess strata of the present invention has the following advantages compared with the prior art:

[0027] This invention relies on the water distribution structure of sand wells and multi-layered surrounding water supply branch pipes, combined with the water guiding of the wellhead ridge slope, to achieve uniform humidification of loess strata at all depths, greatly reduce ineffective water loss, effectively eliminate loess collapsibility, and avoid the defects of traditional pre-soaking water method such as long construction period and large water consumption. It is simple to construct and the humidification effect is highly controllable. Attached Figure Description

[0028] Figure 1 This is a flowchart of a water injection and humidification method for collapsible loess strata according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the system corresponding to the water injection and humidification method for collapsible loess strata in an embodiment of the present invention.

[0030] In the diagram: 1 is a sand well; 2 is a water supply branch pipe; 3 is a ground ridge. Detailed Implementation

[0031] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0032] This invention provides a method for increasing the moisture content of collapsible loess strata through water injection, such as... Figure 1 and Figure 2 As shown, it includes:

[0033] Step 1: Install sand wells 1 in the humidification area and set up multiple layers of water supply pipelines along the axis of sand wells 1. Each layer of water supply pipelines includes multiple water supply branch pipes 2 arranged around sand wells 1, and the inlet of each water supply branch pipe 2 is connected to sand wells 1.

[0034] Step 2: Lay ground ridges 3 around the wellhead of sand well 1, and set up a slope from the ground ridges 3 to the wellhead.

[0035] Step 3: Determine the natural moisture content and volume of the soil in the humidification area, and determine the total water injection volume based on the target moisture content, natural moisture content, and volume.

[0036] Step 4: Inject water into the ridge 3 at a preset water injection rate until the total water volume is reached. The water in the ridge 3 enters the loess in the humidification area through the well wall of the sand well 1 and the outlet of the water supply branch pipe 2.

[0037] This invention utilizes a closed ridge 3 at the wellhead of the sand well 1 to effectively intercept water flow, preventing water waste caused by disorderly overflow and significantly reducing surface evaporation losses. To save costs and resources, the soil used for the ridge 3 is soil extracted during the drilling process. Furthermore, this invention uses a slope to guide the water flow smoothly into the sand well 1, preventing the loess around the wellhead from being eroded by the water flow and ensuring the long-term stability of the wellhead structure of the sand well 1.

[0038] This invention relies on the water distribution structure of the sand well 1 and the multi-layered surrounding water conveyance branch pipe 2, combined with the sloping water guide of the wellhead ridge 3, to achieve uniform humidification of the loess strata at all depths, greatly reduce the ineffective loss of water, eliminate the collapsibility of loess, and avoid the defects of long construction period and large water consumption of traditional pre-soaking method. It is simple to construct and the humidification effect is highly controllable.

[0039] To achieve precise water injection control, thereby reducing water consumption while ensuring humidification effect, the total water injection volume in this embodiment of the invention is determined based on the target moisture content, natural moisture content, and volume. Specifically, it is determined based on the volume of the soil within the humidification area. and average density Determine the quality of the soil; based on the target moisture content With natural water content The difference determines the water shortage; the water loss coefficient is determined. And based on quality, water shortage and water loss coefficient The product determines the total injection volume. Specifically, as shown in formula (1):

[0040] (1)

[0041] For example, the water loss coefficient is 1.05 to 1.15.

[0042] This invention accurately calculates the total water injection volume based on natural moisture content, target moisture content, and soil volume, allowing for on-demand control of the total water injection volume. This avoids the redundancy of water volume in traditional experience-based water injection, significantly reducing the overall water consumption of the project. Simultaneously, by injecting water at a preset rate and combining the dual-channel water outlet of the sand well 1 and the water delivery branch pipe 2, water can slowly and evenly penetrate into the loess pores, preventing the soil structure from being damaged by rapid water flow and ensuring a safe and controllable humidification process.

[0043] In this embodiment of the invention, a sand well 1 is installed in the humidification area. Specifically, a hole is drilled in the humidification area, and a perforated pipe is installed inside the hole. Sand particles are then filled into the perforated pipe to obtain the sand well 1. The particle size of the sand particles gradually decreases from the wellhead to the bottom of the sand well 1. The particle size of the sand particles is 0.25mm to 2mm. For example, the wellhead of the sand well 1 can use large-diameter sand of 0.5mm to 2mm. Large-diameter sand has high porosity, low drainage resistance, and strong flow capacity. The bottom of the sand well 1 can use small-diameter sand of 0.25mm to 0.5mm. Small-diameter sand has a more uniform particle size distribution, which retains sufficient permeability while effectively preventing fine loess particles from flowing into the sand well 1 with the water flow, avoiding siltation and necking problems inside the sand well 1, and ensuring the long-term smooth flow of deep drainage channels.

[0044] This invention features a gradual decrease in sand particle size from the wellhead to the bottom, creating a continuous, permeable layer. This avoids seepage short-circuiting caused by sudden changes in local porosity and maintains low resistance throughout the drainage path of the sand well 1. Simultaneously, the dense filling of deep, small-diameter sand provides stronger lateral support to the borehole wall, effectively preventing borehole collapse and diameter reduction in loess strata.

[0045] In this embodiment of the invention, each layer of the water supply pipeline includes multiple water supply branch pipes 2 arranged around the sand well 1. Specifically, each layer of the water supply pipeline includes multiple water supply branch pipes 2 of different lengths arranged around the sand well 1, and each water supply branch pipe 2 is arranged horizontally. Preferably, each layer of the water supply pipeline includes multiple water supply branch pipes 2 of different lengths arranged around the sand well 1, specifically: each layer of the water supply pipeline includes multiple first water supply branch pipes with a first length and multiple second water supply branch pipes with a second length, the first water supply branch pipes and the second water supply branch pipes are arranged adjacent to each other around the sand well 1. The first length is equal to 1 / 3 of the length from the well wall of the sand well 1 to the outer boundary of the humidification area; the second length is equal to 2 / 3 of the length from the well wall of the sand well 1 to the outer boundary of the humidification area. This invention arranges a first water supply branch pipe (1 / 3 of its length) and a second water supply branch pipe (2 / 3 of its length) adjacent to each other around the sand well 1. This allows the soil within the humidification area, from the well wall of the sand well 1 to the outer boundary of the humidification area, to receive uniform water replenishment, avoiding the problem of uneven wetting and drying, where the area near the well is too wet and the area far from the well is not adequately watered. At the same time, the horizontally arranged pipelines reduce head loss during water supply and can adapt to the soil humidification and consolidation conditions around the sand well 1, significantly improving the uniformity of soil moisture content in the entire humidification area.

[0046] To further improve the uniformity of humidification, in this embodiment of the invention, the lengths of the water supply branch pipes 2 in adjacent layers of water supply pipelines on the same vertical line are different. By arranging the lengths of the water supply branch pipes 2 in adjacent layers of water supply pipelines on the same vertical line in an alternating manner, the water supply coverage of the upper and lower layers can complement each other, filling the local water replenishment blind spots under the arrangement of long and short branch pipes in a single layer. This avoids the problem of continuous water accumulation or insufficient water replenishment at the same vertical position, allowing the entire soil layer from shallow to deep within the humidification area to receive more uniform water replenishment. This further eliminates the humidification dead zones caused by the single-layer pipeline layout and significantly improves the overall humidification uniformity of the soil in three-dimensional space.

[0047] In this embodiment of the invention, after water injection and humidification, a moisture content test is required. Once the moisture content meets the standard and soil collapsibility is ensured, the borehole is backfilled with plain soil (foundation soil) to ensure the compaction and uniformity of the backfill. After backfilling, the top of the borehole is sealed with cement or similar materials to prevent moisture loss and contamination. Post-sealing monitoring is also necessary for a certain period. Regularly checking the soil moisture content and degree of collapsibility ensures the stability and safety of the engineering structure.

[0048] The above descriptions are merely a few embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for increasing moisture content by injecting water into collapsible loess strata, characterized in that, include: Step 1: Install sand wells in the humidification area and set up multiple layers of water supply pipelines along the axis of the sand wells. Each layer of water supply pipelines includes multiple water supply branch pipes arranged around the sand wells, and the inlet of each water supply branch pipe is connected to the sand wells. Step 2: Lay a ground ridge around the wellhead of the sand well, and set up a slope from the ground ridge to the wellhead; Step 3: Determine the natural moisture content and volume of the soil in the humidification area, and determine the total water injection volume based on the target moisture content, the natural moisture content, and the volume; Step 4: Inject water into the ridge at a preset water injection rate until the total water injection volume is reached. The water in the ridge enters the loess in the humidification area through the well wall of the sand well and the outlet of the water delivery branch pipe.

2. The method for injecting water to increase humidity in collapsible loess strata according to claim 1, characterized in that, The total injection volume is determined based on the target moisture content, the natural moisture content, and the volume, specifically as follows: The mass of the soil is determined based on the volume and average density of the soil within the humidification area; The water shortage is determined based on the difference between the target moisture content and the natural moisture content; Determine the water loss coefficient, and determine the total injection volume based on the product of the mass, the water shortage, and the water loss coefficient.

3. The method for injecting water to increase humidity in collapsible loess strata according to claim 1, characterized in that, Sand wells are installed in the humidification area, specifically as follows: Drill holes in the humidification area and install perforated pipes in the drilled holes; Sand particles are filled into the flower tube to form a sand well, wherein the particle size of the sand particles gradually decreases from the wellhead to the bottom of the sand well.

4. The method for increasing moisture content in collapsible loess strata by water injection according to claim 3, characterized in that, The particle size of the sand is 0.25mm to 2mm.

5. The method for injecting water to increase humidity in collapsible loess strata according to claim 1, characterized in that, Each layer of water supply pipeline includes multiple water supply branch pipes arranged around the sand well, specifically: Each layer of water supply pipeline includes multiple water supply branch pipes of different lengths that are arranged around the sand well, and each water supply branch pipe is arranged horizontally.

6. The method for increasing moisture content in collapsible loess strata by water injection according to claim 5, characterized in that, Each layer of water supply pipeline includes multiple water supply branch pipes of different lengths that are arranged around the sand well, specifically: Each layer of water supply pipeline includes multiple first water supply branch pipes with a first length and multiple second water supply branch pipes with a second length, wherein the first water supply branch pipes and the second water supply branch pipes are arranged around the sand well and adjacent to each other.

7. The method for increasing moisture content in collapsible loess strata by water injection according to claim 6, characterized in that, The first length is equal to 1 / 3 of the length from the well wall of the sand well to the outer boundary of the humidification zone; The second length is equal to 2 / 3 of the length from the well wall of the sand well to the outer boundary of the humidification zone.

8. The method for increasing moisture content in collapsible loess strata by water injection according to claim 5, characterized in that, The lengths of the water supply branch pipes in two adjacent layers of water supply pipelines located on the same vertical line are different.

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