An expansive soil slope supporting anchor rod and supporting method based on dry-wet cycle technology

Abstract

The present application relates to a kind of based on wetting and drying cycle technology's expansive soil side slope support anchor rod and supporting method, support anchor rod includes anchor rod body, water amount regulating device and control device;Anchor rod body is equipped with pressure detection device, for when the water content of surrounding soil changes, the confining pressure that the surrounding soil is applied to anchor rod body is detected and sent to control device;Control device is connected to pressure detection device and water amount regulating device respectively, for receiving confining pressure sent by pressure detection device, and according to confining pressure corresponding control water amount regulating device action;Wherein, when the water content of surrounding soil increases and leads to confining pressure greater than preset value, water amount regulating device absorbs and stores the moisture of surrounding soil;When the moisture of surrounding soil reduces and leads to confining pressure less than preset value, water amount regulating device drains to surrounding soil.Will be self-adapting the change of the water content of surrounding soil, avoid support anchor rod to be deformed by excessive confining pressure, can maintain stronger supporting capacity, to effectively support and ramify in turn to soil.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, specifically to an anchor rod and support method for expansive soil slopes based on wet-dry cycle technology. Background Technology

[0002] Landslides are an extremely common adverse geological phenomenon, mainly induced by various external factors, such as groundwater activity, rainfall, erosion of mountain slopes and rivers, earthquakes, and other physical or human activities, which reduce the strength of the slope and cause it to lose its mechanical balance. Under the action of gravity, the slope slides down the weak surface as a whole or in parts.

[0003] Slopes formed during engineering construction in special soil areas are prone to geological disasters such as landslides, collapses, expansion, or spalling when exposed to rain or strong vibrations. To prevent these high-altitude, steep geological disasters, slope stabilization and the establishment of support structures are necessary. Anti-slide piles or prestressed cables, or a combination of both, are commonly used support structures. Based on geological composition, slopes can be divided into the landslide body and the sliding bed from the outside in. The landslide body is also known as the unstable zone, while the sliding bed is called the stable zone. Anti-slide piles or prestressed cables penetrate the landslide body and extend into the sliding bed to resist the sliding force of the landslide body, thus stabilizing the slope.

[0004] Anti-slide piles are selected from wooden piles, steel piles, concrete piles or reinforced (rail) concrete piles, depending on the thickness of the landslide body, the magnitude of the thrust, the waterproofing requirements and construction conditions. Among them, concrete piles are more commonly used.

[0005] The existing anchor support technology for expansive soil has the following technical problems: (1) When expansive soil expands when it comes into contact with water, it will squeeze the anchor rod. When the anchor rod is deformed too much, there is a risk of landslide. (2) During the dry season, the expansive soil loses water and shrinks away from the rod, reducing the frictional resistance and decreasing the support capacity of the anchor rod. (3) When the weather changes drastically, the anchor rod may detach from the soil due to uneven deformation, making it difficult to effectively support and reinforce the soil. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide an anchor rod and support method for expansive soil slope protection based on wet-dry cycle technology. This method can adapt to changes in the moisture content of the surrounding soil, prevent the anchor rod from being deformed due to excessive confining pressure, maintain strong support capacity, and thus effectively support and consolidate the soil.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An anchor bolt for expansive soil slope protection based on wet-dry cycle technology includes an anchor bolt body, a water volume adjustment device, and a control device;

[0009] The anchor bolt body is equipped with a pressure detection device, which is used to detect the confining pressure exerted by the surrounding soil on the anchor bolt body when the moisture content of the surrounding soil changes and send it to the control device.

[0010] The control device is connected to the pressure detection device and the water flow regulating device respectively. It is used to receive the confining pressure sent by the pressure detection device and control the water flow regulating device to operate accordingly based on the confining pressure.

[0011] Specifically, when the moisture content of the surrounding soil increases, causing the confining pressure to exceed the preset value, the water regulating device absorbs and stores the moisture in the surrounding soil; when the moisture content of the surrounding soil decreases, causing the confining pressure to fall below the preset value, the water regulating device drains water into the surrounding soil.

[0012] Furthermore, the water volume regulating device includes a water suction device, a water discharge device, and a valve. The water suction device and the water discharge device are connected to each other through the valve, and the water suction device is located above the water discharge device. The control device is connected to the valve and is used to control the opening and closing of the valve.

[0013] Furthermore, the water absorption device includes a hollow water reservoir and water-absorbing resin. The upper outer wall of the anchor rod body is provided with a water inlet hole. The hollow water reservoir is located inside the anchor rod body. The water-absorbing resin is connected to the water inlet hole and the hollow water reservoir respectively. The valve is located at the lower end of the hollow water reservoir.

[0014] Furthermore, the outer wall of the anchor bolt body is a metal protective plate, and water-absorbing resin is threaded through it with metal wires. One end of the metal wires is connected to the metal protective plate, and the other end is connected to a power source.

[0015] Furthermore, the drainage device includes a water outlet, and the lower outer wall of the anchor bolt body is provided with a water outlet hole. The water outlet is located below the valve and connected to the water outlet hole.

[0016] Furthermore, a water outlet pipe is provided below the valve, with the two ends of the water outlet pipe connected to the valve and the water outlet device respectively, and a Tesla valve is installed inside the water outlet pipe.

[0017] Furthermore, multiple water inlets and outlets are provided, with multiple water inlet spacers located on the upper outer wall of the anchor body and multiple water outlet spacers located on the lower outer wall of the anchor body.

[0018] Furthermore, the pressure detection device is a pressure sensor, which is located on the outer wall of the anchor bolt body.

[0019] Furthermore, the top of the anchor bolt body is equipped with a solar photovoltaic panel and an energy storage device, which are electrically connected to the solar photovoltaic panel and the metal wire, respectively.

[0020] A method for supporting expansive soil slopes using anchor bolts based on wet-dry cycle technology includes the following steps:

[0021] When the moisture content of the soil around the anchor rod changes, the confining pressure exerted by the surrounding soil on the anchor rod body is detected.

[0022] The water volume adjustment device is activated according to the detected confining pressure to adjust the confining pressure exerted on the anchor body by the surrounding soil by adjusting the water content of the soil around the anchor body.

[0023] When the moisture content of the surrounding soil is too high, causing the confining pressure to exceed the preset value, the water volume regulating device absorbs and stores the moisture of the surrounding soil to reduce the expansion of the surrounding soil and thus reduce the confining pressure exerted by the surrounding soil on the anchor body.

[0024] When the moisture content of the surrounding soil is too low, causing the confining pressure to be less than the preset value, the water flow regulating device drains water into the surrounding soil to increase the expansion of the surrounding soil and thus increase the confining pressure exerted by the surrounding soil on the anchor body.

[0025] In summary, the present invention has the following advantages:

[0026] During the rainy season, the water regulation device absorbs and stores excess moisture in the soil surrounding the anchor bolts, reducing the water absorption and expansion of the soil, and lowering the confining pressure exerted by the surrounding soil on the anchor bolts, thus preventing deformation due to excessive confining pressure. During the dry season, the water regulation device drains the stored moisture, increasing the water absorption and expansion of the surrounding soil, and increasing the confining pressure exerted by the surrounding soil on the anchor bolts. This prevents the surrounding soil from shrinking away from the anchor bolts due to water loss during the dry season, thus avoiding a decrease in the frictional resistance of the anchor bolts and a reduction in their supporting capacity. This invention achieves effective support and reinforcement of slope soil by regulating the moisture content of the soil surrounding the anchor bolts. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the support anchor bolt according to an embodiment of the present invention.

[0028] Figure 2 This is a side view of the support anchor bolt according to an embodiment of the present invention.

[0029] Figure 3 This is a cross-sectional view of the support anchor bolt according to an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram illustrating the construction effect of the support anchor bolt according to an embodiment of the present invention.

[0031] In the picture:

[0032] 1-Solar photovoltaic panel; 2-Electric energy storage device; 3-Metal protective plate; 4-Water-absorbing resin; 5-Hollow water tank; 6-Water inlet; 7-Valve; 8-Water outlet pipe; 9-Pressure sensor; 10-Water outlet; 11-Tesla valve; 12-Water outlet. Detailed Implementation

[0033] The present invention will now be described in further detail.

[0034] like Figures 1-3 As shown, an expansive soil slope support anchor based on wet-dry cycle technology includes an anchor body, a water volume adjustment device, and a control device.

[0035] The appearance of the anchor bolt body is roughly similar to that of a regular anchor bolt. The anchor bolt body is equipped with a pressure detection device, which detects the confining pressure exerted by the surrounding soil on the anchor bolt body when the moisture content of the surrounding soil changes and sends this information to the control device.

[0036] The control device is connected to the pressure detection device and the water flow regulating device respectively. It is used to receive the confining pressure sent by the pressure detection device and control the water flow regulating device to operate accordingly based on the confining pressure.

[0037] Specifically, when the moisture content of the surrounding soil increases, causing the confining pressure to exceed the preset value, the water regulating device absorbs and stores the moisture in the surrounding soil; when the moisture content of the surrounding soil decreases, causing the confining pressure to fall below the preset value, the water regulating device drains water into the surrounding soil.

[0038] In existing technologies, anchor bolts are inserted into the soil to support and reinforce slopes. During the rainy season, the soil around the anchor bolts tends to expand due to excessive water absorption, placing excessive confining pressure on the anchor bolts. During the dry season, the soil around the anchor bolts tends to shrink due to water shortage, moving away from the bolt body, resulting in reduced anchor friction and decreased support capacity. This invention addresses this issue by adjusting the moisture content of the soil surrounding the anchor bolts, achieving adaptive adjustment of the confining pressure on the anchor bolt body. This ensures the confining pressure remains near a preset value, allowing the anchor bolts to perform different functions based on soil moisture changes, preventing soil cracking, deformation, and landslides, thus achieving effective support and reinforcement of slopes.

[0039] Specifically, the water regulation device includes a water suction device, a drainage device, and a valve 7. The water suction device and the drainage device are interconnected via the valve 7, with the water suction device positioned above the drainage device. A control device is connected to the valve 7 to control its opening and closing. During the rainy season, when the surrounding soil has a high moisture content, the valve 7 is closed, and the water suction device absorbs and stores moisture from the surrounding soil. During the dry season, when the surrounding soil has a low moisture content, the valve 7 is open, and the water stored in the water suction device is discharged into the surrounding soil through the valve 7 and the drainage device.

[0040] Specifically, the water absorption device includes a hollow water reservoir 5 and water-absorbing resin 4. A water inlet hole 6 is provided on the upper outer wall of the anchor rod body. The hollow water reservoir 5 is located inside the anchor rod body. The water-absorbing resin 4 is connected to both the water inlet hole 6 and the hollow water reservoir 5. A valve 7 is located at the lower end of the hollow water reservoir 5. The outer wall of the anchor rod body is a metal protective plate 3. Metal wires are threaded through the water-absorbing resin 4. One end of the metal wire is connected to the metal protective plate 3, and the other end is connected to the energy storage device 2. The metal wires passing through the water-absorbing resin 4 are responsible for connecting the system to the surrounding soil to form a closed loop. When the rainy season arrives, the energy storage device 2 is turned on to supply power to the closed loop. Excess water in the surrounding soil is absorbed through electroosmosis, and the water enters the water-absorbing resin 4 through the water inlet hole 6 on the outer metal protective plate 3. The size of the water inlet hole 6 should be strictly calculated and controlled. It serves as a channel for water to enter and also as a filter device to prevent surrounding soil particles from entering and disrupting the closed loop. Excess water enters the hollow water reservoir 5 through the water-absorbing resin 4 and is stored therein, preparing for soil moisture content adjustment and support during the dry season.

[0041] Specifically, the drainage device includes a water outlet 10, and a water outlet hole 12 is provided on the lower outer wall of the anchor bolt body. The water outlet 10 is located below the valve 7 and connected to the water outlet hole 12. A water outlet pipe 8 is provided below the valve 7, and both ends of the water outlet pipe 8 are connected to the valve 7 and the water outlet 10, respectively.

[0042] In this embodiment, the pressure detection device is a pressure sensor 9, preferably a strain gauge. Multiple pressure sensors 9 are evenly distributed around the anchor rod body to monitor the slope and the development of the underlying expansive soil in real time during the test. The outer wall of the anchor rod body has multiple grooves, and multiple strain gauges are respectively embedded in these grooves.

[0043] The optimal compressibility index of the soil layer under normal conditions, determined through various experiments, is used as the threshold for pressure sensor 9. Under dry season conditions, the expansive soil loses water and shrinks, causing the surrounding soil to move away from the rod. This not only reduces frictional resistance but also changes the pressure outside the rod. After sensing the pressure change, pressure sensor 9 outside the rod automatically opens valve 7 at the connection between the suction and drainage devices. Water accumulated and stored in the hollow water tank 5 during the rainy season flows downward through valve 7 into the outlet pipe 8 under the influence of gravity.

[0044] The outlet pipe 8 is equipped with a Tesla valve 11 for auxiliary one-way drainage. When the anchor rod is installed at a large tilt angle, the Tesla valve 11 can prevent water backflow and avoid weakening the drainage effect. After the water enters the outlet 10, it flows into the surrounding soil from all directions through multiple outlet holes 12 arranged around the surface of the rod. The expansive soil expands in volume due to water absorption, which will exert pressure on the rod again. When the pressure exerted by the soil on the rod reaches the threshold of the pressure sensor 9, that is, the initial state, the pressure sensor 9 will control the valve 7 to close, preventing the expansive soil from becoming over-expanded due to excessive water absorption during the rainy season. At this time, the water flowing into the soil is natural precipitation during the rainy season, which saves a lot of costs. The water absorption device and the drainage device are combined to form a water volume regulation device, which together maintain the moisture balance inside the surrounding soil to maintain the stability of the expansive soil slope during the dry and rainy seasons.

[0045] Furthermore, the top of the anchor bolt body is provided with a solar photovoltaic power generation panel 1 and an energy storage device 2, which are electrically connected to the solar photovoltaic power generation panel 1 and the metal wire, respectively.

[0046] The anchor body of this invention is an integrated construction facility for supporting and reinforcing slopes and underlying soil layers in expansive soil areas under varying moisture conditions. The water absorption and drainage devices complement each other, allowing for flexible water absorption and drainage according to actual needs, ensuring stability of soil moisture and deformation, achieving the goal of drainage during floods and replenishment during droughts. The pressure sensor 9 controls the opening and closing of valve 7 based on pressure changes caused by soil deformation, thus achieving flexible water storage and drainage functions. The threshold of pressure sensor 9 should be determined experimentally to prevent soil expansion caused by excessive drainage during droughts. The solar photovoltaic panel 1, the internal water absorption and drainage devices, and the pressure monitoring and control system are all detachable, allowing for batch prefabrication and flexible assembly.

[0047] This invention also provides a method for supporting expansive soil slopes using anchor bolts based on wet-dry cycle technology, comprising the following steps:

[0048] When the moisture content of the soil around the anchor rod changes, the confining pressure exerted by the surrounding soil on the anchor rod body is detected.

[0049] The water volume adjustment device is activated according to the detected confining pressure to adjust the confining pressure exerted on the anchor body by the surrounding soil by adjusting the water content of the soil around the anchor body.

[0050] When the moisture content of the surrounding soil is too high, causing the confining pressure to exceed the preset value, the water volume regulating device absorbs and stores the moisture of the surrounding soil to reduce the expansion of the surrounding soil and thus reduce the confining pressure exerted by the surrounding soil on the anchor body.

[0051] When the moisture content of the surrounding soil is too low, causing the confining pressure to be less than the preset value, the water flow regulating device drains water into the surrounding soil to increase the expansion of the surrounding soil and thus increase the confining pressure exerted by the surrounding soil on the anchor body.

[0052] In existing technologies, rigid support is effective for treating expansive soil slopes, but it is costly, has poor deformation coordination, and is prone to failure when the soil undergoes significant deformation. Flexible support technology suffers from complex construction procedures, high maintenance costs, and unsatisfactory long-term support effects. Furthermore, both are primarily used for rainy season protection and are insufficient for addressing water loss during the dry season. They also cannot respond to real-time changes in moisture content.

[0053] This invention utilizes the electroosmotic effect to absorb excess water during the rainy season, significantly reducing construction and subsequent maintenance costs. The photovoltaic panels and the secondary utilization of rainwater are energy-saving and environmentally friendly, reducing resource consumption and avoiding unnecessary waste. The combination of pressure sensor 9 and valve 7 enables automatic water absorption during the rainy season and automatic drainage during the dry season, reducing labor costs. The complementary relationship between the water absorption device and the drainage device achieves flexible prevention and control during the rainy and dry seasons, and ensures that the anchor maintains frictional resistance under the shrinkage of expansive soil, continuously providing support bearing capacity, which is of great significance.

[0054] After the entire anchor rod is prefabricated in the factory, it can be easily transported to the construction site, reducing transportation costs and enabling the free combination of the above functions, which improves the efficiency of slope engineering facilities and reduces manufacturing costs.

[0055] like Figure 4 As shown, a slope example was measured to determine the lithology and various parameters of the soil. Based on its physical and mechanical properties and Poisson's ratio, combined with similarity criteria, similar materials and proportions were determined, and the final placement location, inclination angle, and depth of the anchor rods were determined. First, slope cavities with pre-set angles and depths were drilled ahead of the slope. The anchor rods were installed in the drilled ducts. After measurement and confirmation, the anchor rods were inserted into the expansive soil slope at the pre-designed depth and angle, and grouting was performed on the gap between the anchor section and the drilled duct. After the grouting of the gap between the anchor section and the drilled duct was completed and reached the required strength, the gap between the prestressed sections was filled with filling material. After the grouting of the gap between the anchor rod and the drilled duct was completed and reached the required strength, the filling material was removed, completing the anchor rod support operation.

[0056] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An anchor bolt for expansive soil slope protection based on wet-dry cycle technology, characterized in that: Includes the anchor bolt body, water volume regulating device, and control device; The anchor bolt body is equipped with a pressure detection device, which is used to detect the confining pressure exerted by the surrounding soil on the anchor bolt body when the moisture content of the surrounding soil changes and send it to the control device. The control device is connected to the pressure detection device and the water flow regulating device respectively. It is used to receive the confining pressure sent by the pressure detection device and control the water flow regulating device to operate accordingly based on the confining pressure. Specifically, when the moisture content of the surrounding soil increases, causing the confining pressure to exceed the preset value, the water volume regulating device absorbs and stores the moisture in the surrounding soil; when the moisture content of the surrounding soil decreases, causing the confining pressure to fall below the preset value, the water volume regulating device drains water into the surrounding soil. The water volume regulating device includes a water suction device, a water discharge device, and a valve. The water suction device and the water discharge device are connected to each other through the valve, and the water suction device is located above the water discharge device. The control device is connected to the valve and is used to control the opening and closing of the valve. The water absorption device includes a hollow water reservoir and water-absorbing resin. The upper outer wall of the anchor rod body is provided with a water inlet hole. The hollow water reservoir is located inside the anchor rod body. The water-absorbing resin is connected to the water inlet hole and the hollow water reservoir respectively. The valve is located at the lower end of the hollow water reservoir. The outer wall of the anchor bolt body is a metal protective plate, and water-absorbing resin is threaded through it with metal wires. One end of the metal wires is connected to the metal protective plate, and the other end is connected to a power source.

2. The expansive soil slope support anchor based on wet-dry cycle technology according to claim 1, characterized in that: The drainage device includes a water outlet. The lower outer wall of the anchor bolt body is provided with a water outlet hole. The water outlet is located below the valve and connected to the water outlet hole.

3. The expansive soil slope support anchor based on wet-dry cycle technology according to claim 2, characterized in that: A water outlet pipe is located below the valve, with the valve and water outlet connected to each end of the water outlet pipe, respectively. A Tesla valve is installed inside the water outlet pipe.

4. The expansive soil slope support anchor based on wet-dry cycle technology according to claim 2, characterized in that: Multiple water inlets and outlets are provided. Multiple water inlet spacers are provided on the upper outer wall of the anchor body, and multiple water outlet spacers are provided on the lower outer wall of the anchor body.

5. The expansive soil slope support anchor based on wet-dry cycle technology according to claim 1, characterized in that: The pressure detection device is a pressure sensor, which is located on the outer wall of the anchor bolt body.

6. The expansive soil slope support anchor based on wet-dry cycle technology according to claim 1, characterized in that: The top of the anchor bolt body is equipped with a solar photovoltaic panel and an energy storage device, which are electrically connected to the solar photovoltaic panel and the metal wire respectively.

7. A method for supporting expansive soil slopes using anchor bolts based on wet-dry cycle technology, as described in any one of claims 1-6, characterized in that: Includes the following steps, When the moisture content of the soil around the anchor rod changes, the confining pressure exerted by the surrounding soil on the anchor rod body is detected. The water volume adjustment device is activated according to the detected confining pressure to adjust the confining pressure exerted on the anchor body by the surrounding soil by adjusting the water content of the soil around the anchor body. When the moisture content of the surrounding soil is too high, causing the confining pressure to exceed the preset value, the water volume regulating device absorbs and stores the moisture of the surrounding soil to reduce the expansion of the surrounding soil and thus reduce the confining pressure exerted by the surrounding soil on the anchor body. When the moisture content of the surrounding soil is too low, causing the confining pressure to be less than the preset value, the water flow regulating device drains water into the surrounding soil to increase the expansion of the surrounding soil and thus increase the confining pressure exerted by the surrounding soil on the anchor body.

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