A pile for desaturation of liquefiable foundations and its construction method

Abstract

This invention discloses a pile and its construction method for desaturating liquefiable foundations. The pile includes several layers of desaturation devices arranged around its perimeter. Each layer comprises several desaturation units, spaced apart circumferentially along the pile. Each desaturation unit includes a sealing device and a gas-generating device. The gas-generating device is installed inside the outer wall of the pile via the sealing device. When the soil saturation is insufficient, the sealing device opens, allowing the surrounding soil to act on the gas-generating device to generate gas, thus desaturating the soil. This invention combines the gas-generating properties of chemical mixtures under impact and compression with a foundation desaturation method, achieving the goal of layered reduction of soil saturation around the pile based on different foundation saturation levels. Simultaneously, without affecting the overall performance and bearing capacity of the pile, oxygen, which is not easily soluble in water, is injected into the surrounding soil to desaturate the surrounding foundation.

Description

Technical Field

[0001] This invention relates to a pile and a construction method thereof, and more particularly to a pile and a construction method thereof for desaturating liquefiable foundations. Background Technology

[0002] Saturated sandy soil foundations are widely distributed in coastal areas. These foundations are highly susceptible to large-scale liquefaction when subjected to seismic activity, leading to significant ground settlement and damage. Steel pipe piles are commonly used in soft soils or structures near coastal areas. Traditional steel pipe pile foundation reinforcement primarily focuses on improving the stability of the steel pipe pile structure, without considering the influence of the surrounding soil saturation. However, reducing the saturation of sandy soil foundations can effectively improve the foundation's resistance to liquefaction. Therefore, the method of reducing soil saturation can be applied to the reinforcement of foundations surrounding steel pipe piles.

[0003] Prior to this invention, Chinese invention patent CN 115125935 A, entitled "A device and construction method for encapsulating carbon dioxide to reduce the saturation of sandy soil foundation", disclosed a device for filling saturated foundation with carbon dioxide gas. This device reduces the saturation of the foundation by encapsulating carbon dioxide in the saturated foundation. However, this device requires excavation and drilling in the foundation to carry out the desaturation treatment, which will affect the original foundation.

[0004] Therefore, it is urgent to develop a device and construction method that can reduce the saturation of saturated sandy soil foundations around piles, based on traditional piles, while achieving the effect of reducing soil saturation without affecting the normal use of the pile foundation. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a pile and construction method for desaturating liquefiable foundations. By using oxygen generated from a chemical mixture, the saturation of saturated sandy soil foundations is reduced. This not only does not affect the overall performance and bearing capacity of the original steel pipe piles, but also allows for layered reinforcement of the saturated foundation around the piles. This achieves the goal of effectively reducing the saturation of the soil around the steel pipe piles in layers according to the saturation of the foundation at different heights.

[0006] Technical solution: The present invention includes a pile, and several layers of desaturation devices are arranged around the periphery of the pile. Each layer of desaturation devices includes several desaturation units. The desaturation units located in the same layer are arranged at intervals along the circumference of the pile. Each desaturation unit includes a sealing device and a gas generating device. The gas generating device is installed inside the outer wall of the pile through the sealing device. When the saturation monitoring controller detects that the soil saturation does not meet the requirements, the sealing device is opened, and the gas generating device is generated by the action of the soil around the pile to desaturate the soil.

[0007] The gas-generating device includes a mixture disposed in a groove on the outer wall of the pile.

[0008] The mixture is wrapped with a waterproof membrane, which is fixed to the groove on the outer wall of the pile with bolts. The mixture generates gas under impact and compression conditions to desaturate the soil.

[0009] The groove is sealed by a sealing device to seal the gas generating device inside the groove.

[0010] The sealing device includes a sealing door with a door catch, which closes when the door catch is energized.

[0011] The door catches are connected in parallel in layers along their height, and each parallel branch is equipped with a saturation monitoring controller, which can monitor the resistivity value of the sand in the corresponding area.

[0012] The saturation monitoring controller includes a saturation detector and an automatic switch. The saturation monitoring controller contains a resistance monitoring unit, which can monitor the resistivity value of sand in the corresponding area.

[0013] The sealing door is an electromagnetic sealing door, and the door catcher is an electromagnetic door catcher. The sealing door closes when the electromagnetic door catcher is energized.

[0014] A sealing strip is provided between the sealing door and the groove to seal the groove.

[0015] A construction method for piles used in desaturation of liquefiable foundations includes the following steps:

[0016] Step 1: Arrange the grooves on the piles according to the design requirements;

[0017] Step 2: Secure the gas generating device in the groove, turn on the power switch, and close the sealing device.

[0018] Step 3: Drive the pile into the foundation. After the pile is driven into the foundation, the saturation monitoring controller starts to work. When the saturation of the soil layer does not meet the requirements, the parallel branch of the layer is cut off to form a broken circuit. At this time, the sealing device of the layer is opened, and the soil around the pile rushes in, impacting and squeezing the gas generation device to generate gas.

[0019] Step 4: After the gas generated above overflows into the foundation around the pile, a desaturated zone is formed.

[0020] Beneficial effects: The present invention has the following advantages:

[0021] (1) This invention combines the gas-generating characteristics of a chemical mixture of potassium chlorate and red phosphorus under impact and compression conditions with the foundation aeration desaturation method, thereby achieving the goal of effectively reducing the saturation of the surrounding soil.

[0022] (2) The present invention can carry out layered gas injection saturation operation according to the saturation of different depths of the pile foundation, thereby achieving the purpose of effectively reducing the saturation of the soil around the pile in layers according to the saturation of the foundation at different heights;

[0023] (3) The oxygen generated in this invention is not easily soluble in water. When oxygen is injected into the surrounding soil, it will not react with the pore water in the soil, and can effectively desaturate the surrounding foundation with high water content.

[0024] (4) The electromagnetic door is set on the sealing door to form an electromagnetic sealing door, which can effectively seal the sealing door and protect the gas generating device from the surrounding soil during pile installation and pile driving.

[0025] (5) The present invention installs the gas generating device on the traditional pile, and the cement slurry can be poured normally in the pile pipe. It not only does not affect the overall performance and bearing capacity of the original pile, but also can perform layered reinforcement of the saturated foundation around the pile, and can perform desaturation operation without affecting the overall bearing capacity of the pile. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the parallel connection of the electromagnetic gate suction circuit according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of an electromagnetic sealing door according to an embodiment of the present invention;

[0029] Figure 4 This is a construction diagram of the present invention. Detailed Implementation

[0030] The invention will now be further described with reference to the accompanying drawings.

[0031] like Figures 1 to 3 As shown, the present invention includes a pile 2, with several layers of desaturation devices arranged at intervals around the periphery of the pile 2. Each layer of desaturation devices includes several desaturation units, and the desaturation units in the same layer are arranged at intervals along the circumference of the pile. Each desaturation unit includes a sealing device and a gas generating device. The gas generating device includes a mixture 5, which is wrapped with a waterproof membrane 7. The waterproof membrane 7 wraps the mixture 5 and is fixed to a groove 3 on the outer wall of the pile with bolts. A rubber gasket is installed between the bolts and the mixture 5 to buffer the shaking of the mixture 5 during the pile driving process. Each desaturation unit corresponds to a groove 3, and each groove 3 is sealed by a sealing device, thereby sealing the mixture 5 within the groove 3.

[0032] The sealing device includes a sealing door 4, which is an electromagnetic sealing door. This sealing door can be either a double-leaf sealing door or a single-leaf sealing door; this embodiment uses a double-leaf sealing door. Figure 3 As shown, the length of a single leaf of the double-leaf sealed door is 8–20 cm and the width is 4–10 cm. An electromagnetic door catch 9 is installed on one side of the double-leaf sealed door. The door catch is long and narrow, installed in the middle of the sealed door, and has a length of 8–20 cm and a width of 0.5–1 cm. A sealing strip 8 is provided between the sealed door 4 and the groove 3. Sealing strips 8 are also fixed on both sides of the door gap between the two electromagnetic door catches 9.

[0033] The sealing door 4 closes when the electromagnetic door catch 9 is energized. All electromagnetic door catches 9 are connected in parallel along the height in layers. Each parallel branch is equipped with a saturation monitoring controller 14, which includes a saturation detector and an automatic switch. The saturation monitoring controller 14 contains a resistance monitoring unit, which can monitor the resistivity value R of the sand in the corresponding area. After the pile foundation is driven into the ground, the resistance of the soil around the pile foundation is monitored, and the soil saturation S is measured. r The conversion relationship between S and resistance R can be expressed as: r (-n) -1 = 100(R) a -R b )R a -1 , where: S r R represents the saturation degree of the foundation soil layer; n is a characteristic parameter of the foundation soil, typically taken as 2.0 for sandy soil; a -R b R is the rate of change of resistivity of the foundation soil layer. a The initial resistivity of the foundation soil layer.

[0034] like Figure 2As shown, all electromagnetic sealing doors are connected in parallel via wires and connected to a DC 24V power supply 12 at the top of the pile. The first wire 1 is connected to the negative terminal, and the second wire 2 is connected to the positive terminal. The power supply 12 is kept open during pile foundation layout and unsaturated operations. The electromagnetic door attractor 9 generates a magnetic field that firmly attracts the sealing doors 4 together. After the steel pipe piles are laid out, the saturation of the soil in the area is monitored by the saturation monitoring controller 14. When the resistivity exceeds the standard resistivity range or the soil saturation in the conversion area is 90%, the control switch starts to work, cutting off the parallel branch of the layer and forming a circuit break. The electromagnetic door absorber 9 on the sealing door 4 of the layer is demagnetized and released, and the sealing door 4 opens automatically. The soil around the pile flows into the groove 3, impacting and squeezing the mixture 5 fixed in the groove 3. The mixture 5 can ensure that oxygen is generated after the soil impacts and squeezes. In this embodiment, the mixture 5 is potassium chlorate and red phosphorus. Potassium chlorate is a strong oxidant and phosphorus is a strong reducing agent. When these two mixtures are impacted or squeezed, they easily undergo a chemical reaction to generate oxygen 11. The reaction equation is: 2KClO3=2KCl+3O2↑ (conditions: squeezing, impact). The ratio of potassium chlorate to red phosphorus is 5:6. 1g of the mixture can generate 274ml of oxygen. The gas exists in the soil in the shape of spheres. According to the sphere volume formula V 球 =(4πr) 3 The oxygen bubbles generated by the 1g mixture have a radius of 4-5cm. When designing the spacing of the grooves 3, the spacing between the opposite side walls of the grooves 3 where the 1g mixture is placed is 4-5cm, and so on. The generated oxygen 11 overflows into the foundation 10 and diffuses into the surrounding soil, making the soil around the pile 2 unsaturated, forming a desaturated area 13, which can effectively improve the soil's resistance to liquefaction.

[0035] The construction method of the present invention includes the following steps:

[0036] Step 1: Level the site and arrange the grooves on the piles according to the design requirements;

[0037] Step 2: Determine the center point of the pile hole according to the site requirements, drill the hole and inspect the duct;

[0038] Step 3: After completing the above steps, seal the mixture in sequence and fix it in the groove. At the same time, turn on the power switch. The electromagnetic door will generate magnetic force to tightly close and attract each layer of sealing door.

[0039] Step 4: Align the pile with the hole set in Step 2 and slowly sink it in;

[0040] Step 5: After the pile is driven into the foundation, the saturation monitoring controller starts to work. When the saturation of the soil layer is ≥90%, the control switch cuts off the parallel branch of the layer, forming a circuit break. At this time, the electromagnetic door of the layer is demagnetized and the sealing door is released. The sealing door automatically opens into the groove, and the soil around the pile flows into the groove, impacting and squeezing the mixture to generate oxygen.

[0041] Step Six: After the oxygen generated above overflows into the foundation around the pile, a desaturated zone is formed.

[0042] This embodiment combines the gas-generating characteristics of chlorine-phosphorus mixtures under impact and compression with the foundation desaturation method, achieving the goal of reducing the saturation of the soil around the pile in layers according to the saturation of the foundation at different heights; at the same time, without affecting the overall performance and bearing capacity of the pile, oxygen that is not easily soluble in water is injected into the surrounding soil to desaturate the surrounding foundation.

Claims

1. A construction method for piles used in desaturation of liquefiable foundations, characterized in that, The pile for desaturating liquefiable foundations includes a pile with several layers of desaturation devices arranged around its perimeter. Each layer of desaturation devices includes several desaturation units, which are spaced apart circumferentially along the pile. Each desaturation unit includes a sealing device and a gas-generating device. The gas-generating device is installed inside the outer wall of the pile via the sealing device. The gas-generating device contains a mixture disposed in a groove on the outer wall of the pile, which is sealed by the sealing device. The sealing device includes a sealing door with a door catch. The sealing door closes when the door catch is energized. The sealing door is an electromagnetic sealing door, and the door catch is an electromagnetic door catch. When the saturation monitoring controller detects that the soil saturation does not meet the requirements, the sealing device opens, and the surrounding soil acts on the gas-generating device to generate gas for desaturation. The specific steps include: Step 1: Arrange the grooves on the piles according to the design requirements; Step 2: Secure the gas generating device in the groove, turn on the power switch, and close the sealing device. Step 3: Drive the pile into the foundation. After the pile is driven into the foundation, the saturation monitoring controller starts to work. When the saturation of the soil layer does not meet the requirements, the parallel branch of the layer is cut off to form a broken circuit. At this time, the sealing device of the layer is opened, and the soil around the pile rushes in, impacting and squeezing the gas generation device to generate gas. Step 4: After the gas generated above overflows into the foundation around the pile, a desaturated zone is formed.

2. The construction method for piles used for desaturation of liquefiable foundations according to claim 1, characterized in that, The mixture is wrapped with a waterproof membrane.

3. The construction method for piles used for desaturation of liquefiable foundations according to claim 1, characterized in that, The door catches are connected in parallel in layers along their height, and each layer of parallel branches is equipped with a saturation monitoring controller.

4. A construction method for piles used for desaturation of liquefiable foundations according to claim 3, characterized in that, The saturation monitoring controller includes a saturation detector and an automatic switch.

5. A construction method for piles used for desaturation of liquefiable foundations according to claim 1, characterized in that, A sealing strip is provided between the sealing door and the groove.

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