Water body preloading device and construction method thereof

Abstract

The invention discloses a water body preloading device and a construction method thereof, and belongs to the technical field of foundation treatment. The device comprises a water storage system, a water supply and drainage system and a monitoring system, the water storage system is composed of a rigid supporting structure, an impermeable film and a chain connecting piece, and a stable water storage space can be formed; the water supply and drainage system is used for water injection and extraction; the monitoring system monitors water level, soil pressure and roadbed settlement data in real time. The construction method comprises test preparation, test steps and a data arrangement link, and the test preparation needs to determine parameters, inspect equipment and the like; the test method comprises the steps of field leveling, instrument pre-burying, cushion laying and the like. Data arrangement relates to slope stability coefficient calculation, structure stress analysis and the like. The method is easy and convenient to operate, equipment is simple, repeatability is high, the soft soil foundation treatment effect can be qualitatively and quantitatively evaluated, and support is provided for construction and theoretical research. And meanwhile, water body preloading avoids large-amount earthwork excavation, energy consumption is mainly renewable electric power, and the method has the advantages of being environmentally friendly, economical and sustainable.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation treatment, and particularly to a water body surcharge preloading device and a construction method thereof. Background Art

[0002] In the construction of soft soil foundations, soft soil foundations have characteristics such as poor bearing capacity, high water content, and weak permeability, which often cause settlement problems in engineering construction. This problem not only affects the safety and comfort of driving but also increases the operating costs of railways. Currently, the surcharge preloading and drainage consolidation method is one of the main methods for soft foundation treatment. However, traditional surcharge preloading of soft soil subgrades using subgrade fillers has many drawbacks.

[0003] Patent document CN201810303338.2 discloses a surcharge preloading soft foundation treatment structure and method. A sand cushion layer is laid on the foundation to be surcharged, and a cofferdam is provided on the ground around the sand cushion layer. The area of the preloading treatment range of the foundation to be surcharged is surrounded by the cofferdam to form a cofferdam pit; a waterproof sealing film is laid along the inner surface of the cofferdam in the cofferdam pit and the surface of the sand cushion layer to form a water storage structure, and a number of pumping structures for injecting water into the cofferdam pit are installed on the cofferdam. The present invention adopts the cofferdam water injection surcharge method. First, water is injected for surcharge. After meeting the unloading requirements, the water inside the cofferdam is pumped dry with a water pump, and the plastic cushion layer is removed. However, this method requires a large amount of machinery and surcharge fillers, has complicated construction procedures, high costs, and also has an adverse impact on the local environment.

[0004] Patent document CN201921138188.0 discloses a surcharge preloading soft foundation treatment structure. The technical solution is as follows: A surcharge preloading soft foundation treatment structure includes a foundation to be surcharged. A sand cushion layer is laid on the upper surface of the foundation to be surcharged. Water collecting grooves are respectively formed around the foundation to be surcharged, and a water storage layer for collecting pore water is formed in the water collecting grooves. A surcharge material is laid on the upper surface of the sand cushion layer. By forming water collecting grooves around the foundation to be surcharged and forming a water storage layer inside the water collecting grooves, after the foundation to be surcharged is surcharged and preloaded by the surcharge material, the pore water is stored in the water collecting grooves through the water storage layer, which is beneficial to the centralized collection of the pore water discharged from the foundation to be surcharged.

[0005] Patent document CN201610741481.0 discloses a vacuum combined water covering loading preloading system and its construction method, which includes a water covering cofferdam arranged around the foundation to be preloaded, a vacuum pumping device and a water pumping device arranged within the area surrounded by the water covering cofferdam. The pipe orifice of the vacuum pumping pipe of the vacuum pumping device passes through the sealing membrane and is buried in the sand cushion layer, the discharge pipe orifice of the vacuum pumping device is arranged within the area surrounded by the water covering cofferdam, the water suction pipe orifice of the water pumping device is arranged within the area surrounded by the water covering cofferdam, and the discharge pipe orifice of the water pumping device is arranged outside the area surrounded by the water covering cofferdam. Since a water covering cofferdam is added and a water pumping device is added, the problems of "complicated earthwork loading process, difficult adjustment of later stage load, high transportation and construction costs, and easy environmental pollution during the construction of vacuum combined earthwork surcharge preloading" are solved.

[0006] Although water body preloading has many advantages, such as avoiding the unloading of a large amount of preloading earthwork after the end of the preloading period, improving construction efficiency, saving land, reducing project cost, and being beneficial to soil and water conservation and environmental protection, there is currently a lack of a complete set of water body surcharge preloading devices and construction methods, which limits the application of water body surcharge preloading in on-site construction. Summary of the Invention

[0007] The present invention aims to provide a water body surcharge preloading device and a construction method to solve the deficiencies of the traditional surcharge preloading method in the existing soft soil foundation treatment, achieve efficient, environmentally friendly and economical soft soil foundation treatment, and provide reliable technical support for on-site construction.

[0008] To achieve the above object, on the one hand, the present invention provides a water body surcharge preloading device, including:

[0009] A water storage system, which consists of two rigid support structures, an anti-seepage membrane 2.4 and a chain connector 2.5. The two rigid support structures are connected by the chain connector 2.5, and the anti-seepage membrane 2.4 covers the rigid support structures and the chain connector 2.5 to form a stable water storage space;

[0010] A water supply and drainage system, including a water pump 1.1, a control valve 1.2 and a water pipe 1.3, which is used to inject water or extract water into the water storage system;

[0011] A monitoring system, including a test recorder 3.5, a water level gauge 3.1, an earth pressure gauge 3.3, a displacement gauge 3.2 and a connecting line 3.4. The water level gauge 3.1, the earth pressure gauge 3.3 and the displacement gauge 3.2 are communicatively connected to the test recorder 3.5 through the connecting line 3.4 to monitor the water level, soil pressure and subgrade settlement data in real time.

[0012] Further, the rigid support structure is composed of spliceable rigid members 2.1, 2.2, and 2.3. The length of the water storage system is adjusted by the chain connector 2.5 to adapt to roadbed surfaces of different widths. The rigid support structure has a certain stiffness and self-stability to ensure the stability of the water body during surcharge loading. The chain can be made of light metal materials such as steel, iron, aluminum alloy, or plastic materials, and has a certain tensile property.

[0013] Further, the permeability coefficient of the anti-seepage membrane 2.4 is less than 10 -11 cm / s, and the tensile strength is not less than 50 kN / m. When the anti-seepage membrane is laid, hot melt lap joints, welded lap joints, or special joint tapes are used to connect different strips.

[0014] Further, the water pump 1.1 of the water supply system is an electric water pump, the water pipe 1.3 is a flexible pipe, and a water permeable body and a water isolating body are provided at the end of the water pipe, filled with coarse sand and cohesive soil respectively. The water pump is preferably an electric water pump, which can provide a constant water volume. The control valve can adjust the water volume. The water pipe is preferably a flexible pipe, and its length is determined according to the actual situation.

[0015] Further, the anti-seepage membrane is made of one of polyethylene (PE), polyvinyl chloride (PVC), high-density polyethylene (HDPE), polypropylene (PP), composite geomembrane, or geotextile.

[0016] Further, the water level gauge 3.1 of the monitoring system is an electronic water level gauge. The displacement gauge 3.2 and the earth pressure gauge 3.3 are respectively buried in the surface layer and the deep soil layer of the roadbed, and transmit data to the test recorder 3.5 in real time through the connecting wire 3.4.

[0017] On the other hand, the present invention also provides a construction method based on the above water body surcharge preloading device, which is characterized by including the following steps:

[0018] S1. Select appropriate water body surcharge preloading parameters, test the performance of the test equipment and the water-proof and water-isolating performance of the anti-seepage membrane, determine the preloading position, and set drainage ditches and waterproof measures;

[0019] S2. Level the site, then embed the displacement gauge and the earth pressure gauge, lay the water isolation cushion layer, install and connect the water storage rigid support structure, adjust the length through the chain connector to adapt to the roadbed width, lay and install the water storage anti-seepage membrane, install the water level gauge, then carry out water supply loading and record the settlement data, calculate the best time for water body unloading according to the actual on-site observation situation. When the monitoring results meet the standard requirements, submit an unloading application, turn on the water pump, and backfill the surcharge water into the ground or discharge it into the nearby ditch;

[0020] S3. Organize the data and calculate the stability coefficient of the circular sliding slope;

[0021] Furthermore, the forces on the side plates and connectors of the water body surcharge structure can be analyzed, and the foundation bearing capacity and anti-slip performance can be monitored.

[0022] Furthermore, when injecting water for loading, surface water or groundwater is used as the water source, and the injection rate is dynamically adjusted according to the real-time data of the earth pressure gauge 3.3 and the displacement gauge 3.2.

[0023] Furthermore, when supplying water for loading, water is injected in layers with an interval of 6 hours between each injection; when recording the settlement data, the recorder readings are observed once every 3 days at first, and then once every 15 days thereafter.

[0024] Furthermore, the calculation formula for the stability coefficient of the circular sliding slope is as follows:

[0025]

[0026] In the formula:

[0027] P s -- Slope stability coefficient; c i -- Cohesion of the sliding surface of the i-th calculated slice; -- Angle of internal friction of the sliding surface of the i-th calculated slice; l i -- Length of the sliding surface of the i-th calculated slice; θ i -- Inclination angle of the sliding surface of the i-th calculated slice. When the sliding surface inclination is the same as the sliding direction, it takes a positive value; when the sliding surface inclination is opposite to the sliding direction, it takes a negative value; U i -- Total water pressure per unit width of the sliding surface of the i-th calculated slice; H i -- Self-weight per unit width of the i-th calculated slice; H bi -- Vertical additional load per unit width of the i-th calculated slice; it takes a positive value when the direction points downward and a negative value when it points upward; Q i -- Horizontal load per unit width of the i-th calculated slice; it takes a positive value when the direction points outside the slope and a negative value when it points inside the slope; h wi ,h w,i-1 -- Water head height at the front end of the sliding surface of the i-th and (i - 1)-th calculated slices; γ w -- Unit weight of water, taking 10 kN / m³; i -- Calculated slice number, numbered from the rear; n -- Number of slices.

[0028] Beneficial effects: The water body surcharge preloading device and construction method of the present invention have significant advantages. This test method is easy to operate, highly repeatable, has simple test equipment, high on-site operability, and enriches the surcharge preloading on-site test methods in the railway and highway fields. Through this method, the treatment effect of soft soil foundations can be qualitatively and quantitatively evaluated. The accumulated test data can guide the construction of on-site soft soil foundation treatment, and also has guiding significance for the theoretical research and innovative design of soft soil foundation surcharge preloading. At the same time, water is used as the surcharge material in water body surcharge preloading, avoiding a large amount of earth excavation, reducing the impact on the environment, and having the characteristics of environmental protection. Compared with traditional earth surcharge preloading, the energy consumed in water body surcharge preloading is mainly renewable electric power resources, which is more economical and sustainable. Brief Description of the Drawings

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained. In the drawings:

[0030] Figure 1 : Elevation view of the water body surcharge preloading device system in the present invention;

[0031] Figure 2 : Enlarged view of the rigid components of the water body surcharge preloading device in the present invention;

[0032] Figure 3 : Schematic diagram for calculating the circular arc sliding surface slope in the present invention;

[0033] Figure 4 : Force diagram of the side plate of the water body surcharge structure;

[0034] Figure 5 : Force diagram of the water body surcharge structure;

[0035] Figure 6 : Axial force diagram of the connecting member of the water body surcharge structure;

[0036] Figure 7 : Axial force diagram of the connecting member of the water body surcharge structure;

[0037] Figure 8 : Force diagram of the foundation;

[0038] Figure 9 : Anti-slip diagram of the water body surcharge structure;

[0039] Description of the reference numerals in the drawings: 1.1—water pump, 1.2—control valve, 1.3—water pipe; 2.1, 2.2, 2.3—rigid members, 2.4—anti-seepage membrane, 2.5—chain connector; 3.1—water level gauge; 3.2—displacement gauge, 3.3—earth pressure gauge, 3.4—test connection line; 3.5—test recorder. Detailed implementation manners

[0040] The following will further describe in detail the specific implementation manners of the present invention in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0041] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections.

[0042] For the sake of simplicity of the drawings, only the parts related to the present invention are schematically shown in each drawing, and they do not represent their actual structures as products. In addition, for the sake of simplicity and easy understanding of the drawings, in some drawings, for components with the same structure or function, only one of them is schematically shown, or only one of them is marked. In this article, "one" not only means "only this one", but also can mean the case of "more than one".

[0043] It should also be further understood that the term "and / or" used in the description of this application and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0044] In the embodiments shown in the drawings, the indication of directions (such as up, down, left, right, front and back) is used to explain that the structures and movements of various components of the present invention are not absolute but relative. When these components are in the positions shown in the drawings, these explanations are appropriate. If the descriptions of the positions of these components change, then the indications of these directions also change accordingly.

[0045] In addition, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation manners of the present invention will be described below with reference to the drawings.

[0047] Figure 1It is a schematic diagram of a device for water body surcharge preloading in this embodiment, which includes a water storage system, a water supply system, a drainage system, a monitoring system, etc. The water storage system consists of a rigid support structure, an anti-seepage membrane (the anti-seepage membrane can be made of materials such as polyethylene (PE), polyvinyl chloride (PVC), high-density polyethylene (HDPE), polypropylene (PP), etc., or it can also be composite geomembrane, geotextile, etc. The permeability coefficient should be less than 10-11 cm / s, and the tensile strength should be not less than 50 kN / m; the anti-seepage membrane is generally laid with rolled materials, and reliable methods should be used to ensure strength and anti-seepage between different strips during laying, generally hot melt lap joint, weld lap joint or using special joint tapes can be used. The surface of the anti-seepage membrane should be ensured to be dry and clean before lapping), chain connectors (which can be made of steel, iron, or light metal materials such as aluminum alloy, or can also be made of plastic materials), etc. During the surcharge process, the water body should be ensured to be stable.

[0048] In this embodiment, the rigid support structure should have a certain stiffness and self-stability. The anti-seepage membrane should have certain durability, waterproof and water storage properties, and a simple drainage structure. The chain connectors in this embodiment should have a certain tensile property. The water supply system in this embodiment consists of a water pump, a control valve, and a water pipe, which provides a stable and continuous water flow during the construction process. The water pump is preferably an electric water pump, which can provide a constant water volume and can extract water volume constantly. The control valve should have the function of adjusting the water volume. The water pipe is preferably a flexible pipe, and its length is determined according to the actual situation; generally, a common PVC pipe with a diameter of 10 cm on the market can be used, or other forms of pipe materials can also be used. A water-permeable body is arranged around the lower part of the water inlet pipe, and the water-permeable body is generally filled with clean coarse sand densely. A water-blocking body is arranged around the upper part of the water inlet pipe, and the water-blocking body is generally filled with cohesive soil densely, or can also be filled with cement slurry densely. The drainage system in this embodiment consists of a water extraction pump, a control switch, and a water pipe, which can stably extract the preloading water body during the construction process. From the perspective of cost saving, the water supply system and the drainage system can be jointly composed of a set of systems. The simple drainage structure of the anti-seepage membrane can realize the self-drainage function. The monitoring system in this embodiment consists of a test recorder, a water level gauge, an earth pressure gauge, a displacement gauge, and connecting wires. The test recorder is used to record the data of the water level gauge and the earth pressure gauge during the test process. The water level gauge is preferably an electronic water level gauge, which can accurately measure the water level data of the surcharge system in real time. The earth pressure gauge can accurately measure the pressure magnitude at different depths inside the soil mass in real time. The displacement gauge can accurately measure the settlement displacement change value of the subgrade bed in real time. The connecting wires can connect the water level gauge and the earth pressure gauge to the recorder.

[0049] The on-site construction method and construction process of the device for water body surcharge preloading in the embodiment are as follows:

[0050] (1) Test preparation work

[0051] ① Select appropriate parameters for water body surcharge preloading in combination with the actual on-site conditions and relevant technical standards for subgrade reinforcement.

[0052] ② Inspect the performance of each test equipment and the water-proof performance of the anti-seepage membrane. If unqualified, replace it in time.

[0053] ③ Locate the preloading position through measurement, reasonably set drainage ditches between the subgrade surfaces to ensure smooth drainage during the surcharge preloading stage, and take necessary waterproof measures to prevent water flow from invading the soil mass.

[0054] (2) Test content and steps

[0055] The test content and specific steps of water body surcharge preloading are as follows:

[0056] ① Level the site: Before laying the water body surcharge preloading, the site should be closed to prevent non-construction personnel from approaching, and the subgrade surface should be cleaned to ensure that the surface is clean and free of debris.

[0057] ② Embed displacement gauges and earth pressure gauges: Before carrying out surcharge preloading, embed the displacement gauge 3.2 into the surface layer of the subgrade bed soil mass, embed the earth pressure gauge 3.3 into the appropriate position below the subgrade surface, and connect the connecting wires.

[0058] ③ Lay the water-proof cushion layer: Before carrying out water body surcharge preloading, a water-proof cushion layer should be laid to prevent the subgrade from being eroded by water due to the damage of the anti-seepage membrane 2.4.

[0059] ④ Install and connect the water storage support structure: Assemble the rigid components 2.1, 2.2, and 2.3 in sequence, and assemble two sets, and connect them with the chain connector 2.5. Adjust the length of the chain connector 2.5 according to the width of the subgrade surface required for surcharge preloading to make the support structure adapt to the surcharge preloading requirements.

[0060] ⑤ Lay and install the water storage anti-seepage membrane: After installing the water storage support structure, lay and install the water storage anti-seepage membrane 2.4, and inspect the water-proof and water-separating performance of the anti-seepage membrane.

[0061] ⑥ Install the water level gauge: Install the electronic water level gauge 3.1 inside the anti-seepage membrane to provide water level data. It can be installed on the rigid component 2.3 or installed separately.

[0062] ⑦ Supply water for loading: Install a water pump, connect the plastic water pipe, place the water pipe inside the anti-seepage membrane, turn on the water pump 1.1 and the valve 1.2 to start supplying water. The injection height can be read through 3.1. The specific height should be injected in layers according to the on-site conditions, and the injection interval is 6h each time. The water source can come from the nearby surface water or groundwater. After applying to a certain water level, close the valve.

[0063] ⑧Record settlement data: During the water body surcharge preloading process, the reading of the recorder 3.5 should be observed once every 3 days, and then once every 15 days until unloading. Comprehensively record the observed data, comprehensively analyze the data results, and strictly adjust the water injection rate according to the measurement and control standards. When the settlement amount, settlement rate, and horizontal displacement exceed the design requirements, the preloading should be immediately stopped. After all indicators meet the specification requirements, continue to complete the preloading. During the loading process, when the loading height is close to the design height, the loading rate should be reasonably controlled to avoid damage to the roadbed caused by excessive loading.

[0064] ⑨Unloading: Calculate the optimal time for water body unloading based on the actual on-site observation situation. When the monitoring results meet the standard requirements, submit an unloading application to the supervision unit according to the procedure. After approval, turn on the water pump and backfill the surcharge water into the ground or discharge it into the nearby ditch.

[0065] (3) Data arrangement

[0066] ◆ Calculation method for the stability coefficient of circular arc sliding slopes

[0067] Figure 1 In this embodiment, for the calculation schematic diagram of the circular arc sliding surface slope and water body surcharge preloading, it is necessary to determine the stability coefficient of the slope. The stability coefficient of the slope with a circular arc sliding surface can be calculated according to the following formula:

[0068]

[0069] In the formula:

[0070] P s -- Stability coefficient of the slope;

[0071] c i -- Cohesion of the sliding surface of the i-th calculation strip, in kPa;

[0072] -- Angle of internal friction of the sliding surface of the i-th calculation strip, in °;

[0073] l i -- Length of the sliding surface of the i-th calculation strip, in m;

[0074] θ i -- Inclination angle of the sliding surface of the i-th calculation strip, in °. Take a positive value when the sliding surface inclination is the same as the sliding direction, and a negative value when the sliding surface inclination is opposite to the sliding direction;

[0075] U i -- Total water pressure per unit width of the sliding surface of the i-th calculation strip, in kN / m;

[0076] H i -- Self-weight per unit width of the i-th calculation strip, in kN / m;

[0077] H bi -- The vertical additional load per unit width of the i-th calculation strip, with the unit of kN / m; take the positive value when the direction points downward and the negative value when the direction points upward;

[0078] Q i -- The horizontal load per unit width of the i-th calculation strip, with the unit of kN / m; take the positive value when the direction points outside the slope and the negative value when the direction points inside the slope;

[0079] h wi ,h w,i-1 -- The water head height at the front end of the slip surface of the i-th and (i - 1)-th calculation strips, with the unit of m;

[0080] γ w -- The unit weight of water, take 10 kN / m 3 ;

[0081] i - The calculation strip number, numbered from the rear;

[0082] n - The number of strips.

[0083] ◆ Force on the side plate of the water body surcharge structure

[0084] Figure 4 It is the force diagram of the side plate of the water body surcharge structure. The side plate of the water body surcharge structure is mainly affected by its own gravity, lateral water pressure and the tensile force of the connecting piece. The side plate needs to meet certain hardness and strength requirements.

[0085] ◆ Force on the connecting piece of the water body surcharge structure

[0086] Figure 5 It is the force diagram of the water body surcharge structure, Figure 6 It is the force diagram of the water body surcharge structure, Figure 7 It is the bending moment diagram of the connecting piece of the water body surcharge structure. It can be seen that the water body surcharge preloading structure is mainly affected by its own gravity, vertical water pressure and lateral pressure, as well as frictional force. Among them, the stiffness and strength requirements of the components should meet the requirements of the lateral and vertical water pressures. The bending resistance performance of the connecting piece needs to meet both greater than And the torsional resistance performance of the connecting piece needs to meet both greater than

[0087] ◆ Bearing capacity of foundation

[0088] The bearing capacity of the foundation σ0 should meet σ0 > F3, as Figure 8 shown.

[0089] ◆ Anti-slip of the water body surcharge structure

[0090] Figure 9It is the anti-slip diagram of the water body surcharge structure. It can be seen that the anti-slip force is mainly friction. If the friction does not meet the requirements, a chain needs to be connected between the water body surcharge preloading devices to provide the tensile force F 拉 , and the strength of the chain itself needs to be able to withstand the magnitude of F 拉 , and it needs to meet (it can be taken as not less than 2.0). Among them

[0091] The embodiments described above are some embodiments of the present invention, rather than all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts fall within the scope of protection of the present invention.

Claims

1. A water body heap preloading device, characterized in that: include: A water storage system, comprising two rigid support structures, an impermeable membrane (2.4) and a chain connecting piece (2.5), wherein the two rigid support structures are connected via the chain connecting piece (2.5), and the impermeable membrane (2.4) covers the rigid support structures and the chain connecting piece (2.5) to form a stable water storage space; A water supply and drainage system, comprising a water pump (1.1), a control valve (1.2) and a water pipe (1.3), for injecting water into or extracting water from the water storage system; The monitoring system comprises a test recorder (3.5), a water level meter (3.1), an earth pressure meter (3.3), a displacement meter (3.2) and a connecting line (3.4); the water level meter (3.1), the earth pressure meter (3.3) and the displacement meter (3.2) are connected to the test recorder (3.5) through the connecting line (3.4) for real-time monitoring of water level, earth pressure and roadbed settlement data.

2. The water body preloading device according to claim 1, characterized in that: The rigid support structure is composed of rigid components (2.1, 2.2, 2.3) that can be spliced, and the length of the water storage system is adjusted through a chain connector (2.5) to adapt to roadbed surfaces of different widths.

3. The water body preloading device according to claim 1, characterized in that: The permeability coefficient of the anti-seepage membrane (2.4) is less than 10 -11 cm / s, and the tensile strength is not less than 50kN / m. When the anti-seepage membrane is laid, different strips are connected by hot-melt overlap, weld overlap or special seam tape.

4. The water body preloading device according to claim 1, characterized in that: The water pump (1.1) of the water supply system is an electric water pump, the water pipe (1.3) is a flexible pipe, and a permeable body and a water-blocking body are provided at the end of the water pipe, which are filled with coarse sand and clay respectively.

5. The water body preloading device according to claim 1, characterized in that: The anti-seepage membrane is made of one of polyethylene (PE), polyvinyl chloride (PVC), high-density polyethylene (HDPE), polypropylene (PP), composite geomembrane or geotextile.

6. The water body preloading device according to claim 1, characterized in that: The water level meter (3.1) of the monitoring system is an electronic water level meter, and the displacement meter (3.2) and the soil pressure meter (3.3) are respectively buried in the surface layer and deep soil of the roadbed, and transmit data in real time with the test recorder (3.5) through the connecting line (3.4).

7. A construction method for the water body preloading device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, select appropriate water body preloading parameters, inspect the performance of the test equipment and the water-proof and waterproof performance of the anti-seepage membrane, determine the preloading position and set up drainage ditches and waterproof measures; S2, level the site, then bury displacement meters and earth pressure meters, lay water-proof cushions, install and connect the rigid support structure for water storage, adjust the length to suit the width of the roadbed through chain connectors, lay and install water storage anti-seepage membranes, install water level meters, then load water and record settlement data, calculate the best time for water unloading based on actual on-site observations, submit an unloading application when the monitoring results meet the standard requirements, turn on the pump, and backfill the heap water into the ground or discharge it into a nearby ditch; S3, data collation, calculation of the stability coefficient of the circular sliding slope.

8. The construction method according to claim 7, characterized in that: When water injection is used for loading, the water source is surface water or groundwater, and the injection rate is dynamically adjusted according to the real-time data of the earth pressure gauge and displacement meter.

9. The construction method according to claim 7, characterized in that: When the water supply is loaded, water is injected in layers, and the interval between each injection is 6 hours; when recording the settlement data, the recorder readings are first observed once every 3 days, and then once every 15 days.

10. The construction method according to claim 7, characterized in that: The calculation formula of the arc sliding slope stability coefficient is: Where: P s --slope stability coefficient; c i --The cohesion of the sliding surface of the i-th calculated strip; φ i --The internal friction angle of the sliding surface of the i-th calculated strip; l i --The length of the sliding surface of the i-th calculated strip; θ i --The inclination of the sliding surface of the i-th calculated strip is positive when the sliding surface inclination is the same as the sliding direction, and negative when the sliding surface inclination is opposite to the sliding direction; U i --Total water pressure per unit width on the sliding surface of the i-th calculated strip; H i --The self-weight per unit width of the i-th calculated strip; H bi --Vertical additional load per unit width of the i-th calculation strip; when the direction points downward, it takes a positive value, and when it points upward, it takes a negative value; Q i --Horizontal load per unit width of the i-th calculation strip; when the direction points to the outside of the slope, it is positive, and when it points to the inside of the slope, it is negative; h wi ,h w,i-1 --Height of water head at the front end of the strip sliding surface calculated for the i-th and i-1-th times; γ w --Water density, take 10kN / m3; i--calculation bar number, starting from the back; n--number of bars.

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