Heating combined vacuum well point foundation pit dewatering system and using method thereof

Abstract

The invention discloses a heating combined vacuum well point foundation pit dewatering system and a using method thereof, and belongs to the technical field of engineering construction.The heating combined vacuum well point foundation pit dewatering system comprises a foundation pit area formed by surrounding a natural ground, and soil body heating units are annularly arranged on the periphery of the foundation pit area at intervals; the soil body heating unit is provided with a heating element for heating a soil body which is not less than the depth of the foundation pit; well point dewatering units are arranged on the periphery of the foundation pit area in the circumferential direction at intervals and located on the outer side of the soil body heating unit. According to the system, the water permeability of the low-permeability soil layer is improved through heating, the precipitation efficiency is remarkably improved, the period is shortened, different foundation pit requirements are met, precipitation rate control and energy consumption optimization are achieved by optimizing the vacuum degree and the heating temperature, and therefore the construction cost is reduced, and the overall construction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering construction, and in particular relates to a heating combined vacuum well point foundation pit dewatering system and a use method thereof. Background Art

[0002] Foundation pit dewatering is a crucial technical link in geotechnical engineering, which is directly related to the guarantee of construction safety and quality. By designing a scientific, economically reasonable dewatering plan and selecting an appropriate dewatering method, the groundwater level can be effectively controlled, and the buoyancy of water on the foundation pit slope and bottom plate can be reduced, thereby preventing the occurrence of dangerous situations such as foundation pit collapse and water gushing. At the same time, safe and reliable dewatering methods can not only help reduce the difficulty of construction, but also shorten the construction period, reduce construction costs, and ensure the smooth progress of foundation pit excavation and subsequent projects. Therefore, the reasonable design and implementation of foundation pit dewatering plans are of great significance to ensure the safety, stability and quality of foundation pit construction.

[0003] The well point dewatering method is a commonly used dewatering technology for foundation pits. Usually, a certain number of filter pipes are buried around the foundation pit before excavation, and then the groundwater is pumped out through pumping equipment to reduce the groundwater level within the foundation pit to the designed depth to ensure the smooth progress of the foundation pit construction. This method is not only suitable for foundation pits of various geometric shapes, but also can effectively overcome the problem of quicksand, stabilize the slope and reduce the pressure outside the foundation pit. Among the many dewatering methods, vacuum well point dewatering technology is particularly common. It uses vacuum pumping equipment to efficiently dewater while overcoming the special environmental conditions of high groundwater levels, avoiding slope instability or water gushing caused by excessive water pressure in the foundation pit. Because of its simple operation and significant effect, this technology is particularly suitable for construction sites with abundant groundwater and complex soil.

[0004] Although the vacuum wellpoint dewatering method is widely used in many foundation pit constructions, it still faces some significant challenges and shortcomings in certain types of strata, especially in clay strata with low permeability coefficients. The permeability of such strata is poor, and groundwater is difficult to flow smoothly into the filter pipe, resulting in a significant decrease in the efficiency of traditional vacuum wellpoint dewatering and failure to achieve the expected water level reduction effect. At the same time, in areas with a large amount of clay soil, the vacuum effect is difficult to fully exert, resulting in unstable water level control. In addition, this method also has the problem of high energy consumption during the pumping process, and long-term operation may cause equipment wear and increased maintenance costs. In order to cope with these shortcomings, the engineering community has proposed a variety of improvement schemes, such as the electroosmotic wellpoint method and the electroosmotic combined vacuum wellpoint method, which enhance the mobility of water molecules and accelerate the discharge of groundwater by applying an electric field underground. However, these forced dewatering methods have complex processes, high equipment requirements, high difficulty in operation, and significantly increased initial investment and operating costs, which limit their widespread application in large-scale projects. Therefore, the traditional vacuum wellpoint dewatering method still faces a series of shortcomings such as low efficiency, high energy consumption, and increased costs when dealing with low permeability soil layers. Summary of the invention

[0005] In response to the problems existing in the prior art, the present invention provides a heating combined vacuum well point pit dewatering system and a method of using the system, which aims to solve the problems of low dewatering efficiency, high energy consumption and increased cost of traditional vacuum well point dewatering methods in low permeability clay formations.

[0006] The present invention is implemented as follows: a heating combined vacuum well point foundation pit dewatering system, characterized in that: it includes a foundation pit area formed by natural ground, soil heating units are arranged at intervals around the periphery of the foundation pit area, and the soil heating units have heating elements for heating soil not less than the depth of the foundation pit; well point dewatering units are arranged at intervals around the periphery of the foundation pit area, and the well point dewatering units are located outside the soil heating units.

[0007] In the above technical solution, preferably, the natural ground of the soil heating unit is formed into an annular heating area, the natural ground of the well point precipitation unit is formed into an annular precipitation area, and a temperature monitoring unit is arranged between the annular heating area and the annular precipitation area, and the temperature monitoring unit has a temperature sensing element for monitoring the temperature of soil not less than the depth of the foundation pit.

[0008] In the above technical solution, preferably, the wellpoint dewatering unit includes a wellpoint pipe, a filter pipe and a water pump, the wellpoint pipe is vertically inserted into the soil, the depth of the lower end of the wellpoint pipe inserted into the soil is greater than the depth of the foundation pit, the filter pipe is arranged at the lower end of the wellpoint pipe, and the upper end of the wellpoint pipe is connected to the water pump.

[0009] In the above technical solution, preferably, the upper ends of the well-point pipes of all the well-point dewatering units are connected to a water collecting pipe, and the water pump is connected to the well-point pipes of each of the well-point dewatering units through the water collecting pipe.

[0010] In the above technical solution, preferably, the soil heating unit includes a power supply and the heating element connected to the power supply, and the heating element is a heating rod vertically inserted into the soil.

[0011] In the above technical solution, preferably, the temperature monitoring unit includes a temperature collector and the temperature monitoring unit connected to the temperature collector, and the temperature sensing element of the temperature monitoring unit includes a signal line extending vertically in the soil and N temperature sensors connected in series through the signal line.

[0012] The heating combined vacuum well point foundation pit dewatering system and the use method thereof of the present invention have many significant advantages and effects, are suitable for foundation pit dewatering treatment in low permeability formations, and solve the shortcomings of traditional dewatering methods in such formations.

[0013] First of all, the system has a simple construction method, convenient operation, and low consumables cost. It can be effectively applied to low-permeability strata, such as clay strata, providing convenient conditions for subsequent foundation pit excavation and construction. Compared with the traditional precipitation system, the present invention introduces a heating rod to improve the permeability of the soil by heating the soil. Especially in clay soil, this heating process significantly enhances the water permeability of the soil layer, which greatly improves the precipitation efficiency of the vacuum well point system. The combination of heating and vacuum not only speeds up the precipitation speed, but also greatly shortens the precipitation cycle, thereby improving the overall construction efficiency.

[0014] In addition, by flexibly adjusting the layout and parameters of the well point pipe, heating rod and vacuum pump, the system can adapt to the needs of foundation pit dewatering under different sizes, depths and geological conditions, showing strong adaptability. This adjustability enables the system to provide customized solutions for various engineering needs, ensuring the efficient and stable dewatering process. More importantly, the system can accurately control the precipitation rate by reasonably adjusting the vacuum degree and heating temperature, ensuring that the precipitation reaches the design target while optimizing energy consumption. This not only reduces the energy consumption of the system operation, but also reduces the construction cost while ensuring the construction quality, with significant economic benefits and environmental protection effects. Therefore, the heating combined vacuum well point foundation pit dewatering system of the present invention shows excellent effects in improving precipitation efficiency, saving costs, shortening construction period and optimizing energy consumption, and is suitable for promotion and application under various complex foundation pit conditions.

[0015] The second object of the present invention is to provide a method for using the above-mentioned heating combined with vacuum well point foundation pit dewatering system, which is characterized by comprising the following steps:

[0016] S1. Delineate the foundation pit area;

[0017] S2. Design the system location according to soil conditions, including the number and spacing of well point dewatering units and soil heating units, as well as the distance between well point dewatering units and soil heating units;

[0018] S3. Install the system according to the location design results;

[0019] S4. The soil heating unit preheats the soil;

[0020] S5. Pump water from the soil using well point dewatering units;

[0021] S6.Precipitation is completed and the demolition system is removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a cross-sectional schematic diagram of the present invention;

[0023] Figure 2 It is a three-dimensional schematic diagram of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] In order to solve the problems of low dewatering efficiency, high energy consumption and increased cost in the traditional vacuum well point dewatering method in low permeability clay strata, the present invention provides a heating combined vacuum well point foundation pit dewatering system and its use method. The system improves the permeability of the low permeability soil layer by heating, significantly improves the dewatering efficiency, shortens the cycle, and adapts to different foundation pit requirements. By optimizing the vacuum degree and heating temperature, the dewatering rate control and energy consumption optimization are achieved, thereby reducing construction costs and improving overall construction efficiency. In order to further illustrate the structure of the present invention, the detailed description is as follows in conjunction with the accompanying drawings:

[0026] See also Figure 1 and Figure 2 , a heating combined vacuum well point foundation pit dewatering system, including a foundation pit area surrounded by natural ground. The foundation pit area is an area drawn on the natural soil body to be excavated to form a foundation pit.

[0027] Soil heating units are arranged at intervals around the periphery of the foundation pit area, and the soil heating units have heating elements for heating soil that is not less than the depth of the foundation pit. In this embodiment, the soil heating unit includes a power supply 7 and a heating element connected to the power supply, and the heating element is a heating rod 3 vertically inserted into the soil. The bottom surface 9 of the foundation pit is the maximum depth of the foundation pit.

[0028] Wellpoint dewatering units are arranged at intervals around the periphery of the foundation pit area, and the wellpoint dewatering units are located outside the soil heating unit. In this embodiment, the wellpoint dewatering unit includes a wellpoint pipe 1, a filter pipe 2 and a pump. The wellpoint pipe is vertically inserted into the soil, and the depth of the lower end of the wellpoint pipe inserted into the soil is greater than the depth of the foundation pit. The filter pipe is arranged at the lower end of the wellpoint pipe, and the upper end of the wellpoint pipe is connected to the pump. The upper ends of the wellpoint pipes of all wellpoint dewatering units are connected to the water collecting pipe 5, and the pump is connected to the wellpoint pipes of each wellpoint dewatering unit through the water collecting pipe. Further, the wellpoint pipe is connected to the water collecting pipe by a connecting pipe 6, and the water collecting pipe is a circular pipe, forming the main channel of the dewatering system. The pump is a vacuum pump 10, and the vacuum pump performs a vacuum operation on the wellpoint pipe through the water collecting pipe to form a negative pressure environment, which prompts groundwater to enter the wellpoint pipe through the filter pipe. The well point pipe has a diameter of Φ50mm-Φ100mm and is made of high-strength, corrosion-resistant materials such as high-density polypropylene, stainless steel or PVC. The well point pipes are evenly arranged around the foundation pit, and the distance between the well point position and the periphery of the foundation pit is not less than 2m. The filter pipe is located at the bottom of the well point pipe, is 50cm long, has a pore size of 5mm-10mm, and is wrapped with filter cloth. The heating rod is arranged between the well point pipe and the edge of the foundation pit, and the distance between the heating rod and the well point pipe is 0.5m-1.5m. The power supply provides power support for the heating rod and the vacuum pump.

[0029] The natural ground 11 of the soil heating unit is set to form an annular heating area, and the natural ground of the well point precipitation unit is set to form an annular precipitation area. A temperature monitoring unit is set between the annular heating area and the annular precipitation area. The temperature monitoring unit has a temperature sensing element for monitoring the temperature of the soil that is not less than the depth of the foundation pit. In this embodiment, the temperature monitoring unit includes a temperature collector 8 and a temperature monitoring unit connected to the temperature collector. The temperature sensing element of the temperature monitoring unit includes a signal line vertically extending in the soil and N temperature sensors 4 connected in series through the signal line. The temperature sensor is arranged between the heating rod and the well point pipe, and is used to monitor the soil temperature in real time.

[0030] Increased soil temperature can have a significant effect on permeability, primarily by affecting the physical properties of water in the soil and the interactions between particles. First, increased temperature reduces the viscosity of water, thereby reducing the resistance to water flowing through the soil and increasing the rate of infiltration. In addition, higher temperatures can cause evaporation of pore water in the soil, thereby reducing the volume of the liquid phase, increasing the porosity between soil particles and further increasing permeability. Changes in temperature can also cause soil particles to expand or contract, changing the pore structure and affecting the flow path of water. Therefore, increased temperature generally helps to increase the permeability of soil, but the specific effect depends on the composition and structure of the soil.

[0031] The heating combined vacuum well point foundation pit dewatering system of the present invention has the advantages of simple construction method, low consumables cost, strong adaptability, etc., and is particularly suitable for foundation pit dewatering treatment in low permeability formations. By improving the permeability of the soil through the heating rod, the system significantly improves the dewatering efficiency and shortens the construction period. By reasonably regulating the vacuum degree and heating temperature, the dewatering rate control and energy consumption optimization are achieved. In addition, the system can be flexibly adjusted according to the needs of foundation pits of different sizes and depths, and customized solutions can be provided, thereby reducing construction costs, improving construction efficiency and reducing energy consumption, with good economic benefits and environmental protection effects.

[0032] The method for using the above-mentioned heating combined with vacuum well point foundation pit dewatering system comprises the following steps:

[0033] S1. Delineate the foundation pit area. Rationally lay out the material storage area and ensure that the construction site is well connected, leveled and leveled.

[0034] S2. Design the system location according to soil conditions, including the number and spacing of wellpoint dewatering units and soil heating units, as well as the distance between wellpoint dewatering units and soil heating units. According to the size of the foundation pit and geological conditions, the spacing of the wellpoint pipes is determined to be 1.5m, and a total of 40 wellpoint pipes are arranged. The heating rods are arranged between the wellpoint pipes and the edge of the foundation pit, 1.0m away from the wellpoint pipes, and a total of 40 heating rods are arranged. The vacuum pump is selected with a suction rate of 30m 3 / h, power of 3kW. Use positioning base station and positioning terminal to accurately locate the well point.

[0035] S3. Install the system according to the location design results: the foundation pit size is 20m×30m, the depth is 6m, and the geological conditions are silty clay. According to the design requirements, the well point pipe, filter pipe, connecting pipe, water collecting pipe, temperature sensor and heating rod are reasonably installed. The vacuum pump is installed on the foundation and connected to the water collecting pipe. The water collecting pipe is connected to all the connecting pipes on the site. The connecting pipe is connected to the well point pipe, the temperature sensor is connected to the temperature collector, and the circuit is reasonably arranged. The circuit is connected to the power supply to ensure the normal operation of the system.

[0036] Drilling: Drill holes at the well point location for installing well point pipes and filter pipes, which are pressed into the soil by machinery, but it must be ensured that they are pressed vertically into the soil.

[0037] Pipe burying: Before burying the pipe, embed the filter pipe into the bottom opening of the well point pipe, and use the lifting equipment and limiting equipment to accurately bury the well pipe.

[0038] Backfilling of well point holes: Fill sand between the well point hole and the well point pipe, and seal it with clay when it is at least 1000mm away from the ground.

[0039] Dewatering system connection: Roll a layer of expansion water stop strip on the upper end of the well point pipe and connect it to the water collecting pipe through a connecting pipe.

[0040] Heating system: Press the heating rod and temperature sensor into the soil layer at the designated position by mechanical equipment. Pay attention to pressing the equipment vertically, and connect the heating rod and temperature sensor to the power supply and temperature acquisition instrument respectively.

[0041] Install the vacuum pump: Check the vacuum pump and motor to ensure that there is no damage during transportation and loading and unloading; check the tools and lifting machinery, and check the foundation of the machine. The foundation surface should be leveled before installing the vacuum pump. If it is uneven, use shims to adjust it to a level surface. Connect the vacuum pump in the site to the water collection pipe and guide the sucked water into the pre-set water storage area.

[0042] S4. The soil heating unit preheats the soil. Turn on the power, start the heating rod for preheating, collect data through the temperature sensor and summarize it to the temperature collector to realize real-time monitoring of soil temperature. The preset temperature range is 50℃-60℃, and the preheating time of the heating rod is 3 hours.

[0043] Turn on the power of the heating rod to preheat the soil layer; when the temperature of the heating rod is greater than 80°C, the heating rod stops supplying power; when the temperature of the heating rod is less than 75°C, the heating rod starts supplying power; when the soil temperature sensor indicates that the temperature reaches above the preset temperature, turn on the vacuum pump; under the action of vacuum negative pressure, the groundwater is sucked into the well point pipe through the filter tube, and then continues to be sucked into the water collection pipe and pumped into the water storage tank outside the foundation pit.

[0044] S5. Use the well point dewatering unit to pump water from the soil. When the soil temperature reaches the preset value, start the vacuum pump to dewater. During the dewatering process, regularly check the vacuum pump's pumping rate and ultimate vacuum degree to ensure the dewatering effect. At the same time, monitor the soil temperature in real time through the temperature sensor. If the temperature is found to be too high or too low, adjust the heating power in time.

[0045] S6. Dewatering is completed and the system is removed. After continuous dewatering, the groundwater level in the foundation pit drops to the designed depth, and drops from the initial groundwater level 12 to the groundwater level 13 after dewatering, and dewatering is completed. After the foundation pit construction is completed, turn off the power supply and stop the operation of the vacuum pump and heating rod. After the vacuum heating system cools down, remove all well point pipes, filter pipes, connecting pipes, water collection pipes, temperature sensors, heating rods and other equipment in the site.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heating combined vacuum well point foundation pit dewatering system, characterized by: It includes a foundation pit area surrounded by natural ground, and soil heating units are arranged at intervals around the periphery of the foundation pit area. The soil heating units have heating elements for heating soil no less than the depth of the foundation pit; well point dewatering units are arranged at intervals around the periphery of the foundation pit area, and the well point dewatering units are located outside the soil heating units.

2. The heating combined vacuum well point foundation pit dewatering system according to claim 1 is characterized by: The natural ground of the soil heating unit is formed into an annular heating area, the natural ground of the well point precipitation unit is formed into an annular precipitation area, and a temperature monitoring unit is arranged between the annular heating area and the annular precipitation area. The temperature monitoring unit has a temperature sensing element for monitoring the temperature of soil not less than the depth of the foundation pit.

3. The heating combined vacuum well point foundation pit dewatering system according to claim 1 is characterized by: The wellpoint dewatering unit includes a wellpoint pipe, a filter pipe and a water pump. The wellpoint pipe is vertically inserted into the soil. The depth of the lower end of the wellpoint pipe inserted into the soil is greater than the depth of the foundation pit. The filter pipe is arranged at the lower end of the wellpoint pipe, and the upper end of the wellpoint pipe is connected to the water pump.

4. The heating combined vacuum well point foundation pit dewatering system according to claim 3 is characterized by: The upper ends of the well point pipes of all the well point dewatering units are connected to the water collecting pipe, and the water pump is connected to the well point pipes of each well point dewatering unit through the water collecting pipe.

5. The heating combined vacuum well point foundation pit dewatering system according to claim 1 is characterized by: The soil heating unit comprises a power source and the heating element connected to the power source, and the heating element is a heating rod vertically inserted into the soil.

6. The heating combined vacuum well point foundation pit dewatering system according to claim 2 is characterized by: The temperature monitoring unit includes a temperature collector and the temperature monitoring unit connected to the temperature collector. The temperature sensing element of the temperature monitoring unit includes a signal line vertically extending in the soil and N temperature sensors connected in series through the signal line.

7. A method for using the heating combined vacuum well point foundation pit dewatering system according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Delineate the foundation pit area; S2. Design the system location according to soil conditions, including the number and spacing of well point dewatering units and soil heating units, as well as the distance between well point dewatering units and soil heating units; S3. Install the system according to the location design results; S4. The soil heating unit preheats the soil; S5. Pump water from the soil using well point dewatering units; S6.Precipitation is completed and the demolition system is removed.

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