CN102383437B - Well point positioned pumping tubular well and well point positioned pumping method - Google Patents

Abstract

The invention is applied to the field of drain of tubular wells and provides a well point positioned pumping tubular well and a well point positioned pumping method. The pumping tubular well comprises a sand-free tube well section and a water storage tube well section, wherein the sand-free tube well section is positioned above a certain position of a first water-resisting layer below the precipitation depth of a foundation pit and is used for collecting a water source in a water-containing layer within the precipitation depth of the foundation pit; and the water storage tube well section is positioned below the certain position of the first water-resisting layer below the precipitation depth of the foundation pit, is connected with the sand-free tube well section and is used for storing the water source in the water-containing layer within the precipitation depth of the foundation pit. According to the well point positioned pumping tubular well and the well point positioned pumping method disclosed by the invention, by adopting a precipitation tubular well consisting of the sand-free tube well section and the water storage tube well section, the water source in the water-containing layer within the precipitation depth of the foundation pit is effectively collected, the effect that more water and the precipitated water are pumped without polluting an underground water source in an independent water-containing source below the precipitation depth of the foundation pit is realized, and the difficult problem that the water cannot be dredged under the condition that water cannot be dredged is solved. In addition, by adopting an automatic pumping method with a positioned water level, the total pumping time is greatly shortened and the cost of foundation pit engineering is greatly reduced.

Description

A well point positioning pumping tube well and well point positioning pumping method

technical field

The invention belongs to the field of tube well drainage, and in particular relates to a well point positioning pumping tube well and a well point positioning pumping method.

Background technique

Whether it is a high-rise building foundation or an underground building, when it is below the groundwater level, it is generally necessary to lower the groundwater level to ensure the convenience and safety of construction. Foundation pit dewatering reduces the groundwater level within the scope of the foundation pit within a certain period of time through pumping and drainage, so as to ensure the construction environment of the foundation pit excavation, and at the same time provide a strong guarantee for the stability of the foundation pit floor and slope. In terms of groundwater control methods, there are two types of groundwater control methods for foundation pits: water stop method and precipitation method. The water-stop method is to form a water-stop curtain around the foundation pit through effective means to stop the groundwater outside the foundation pit, such as anti-seepage vertical curtains, underground continuous walls, etc.; the precipitation method is to reduce the groundwater within the foundation pit, such as open ditch Drainage method, well point precipitation method, etc. At present, the precipitation method is widely used in foundation pit engineering. Precipitation methods include vertical well point method, self-seepage well method, radiation well method, and their combination methods.

In the precipitation of these conventional vertical well points, a special phenomenon can often be encountered, that is, there is no water in the vertical well when it is pumped, and there is water when it stops, and there is still water during excavation. This phenomenon is called "sparseness". Theoretically speaking, "sparse but not dry" exists in the situation shown in Figure 1, that is, no matter how the vertical precipitation wells are arranged and how strong the pumping intensity is, there will always be a certain amount of groundwater at the bottom interface of the aquifer, resulting in Part of the pit is below the theoretical soaking line, that is, the groundwater level within the pit cannot be lowered to 0.5m below the pit.

The phenomenon of "draining and not drying" makes groundwater still exist in the aquifer. When the foundation pit is excavated, the residual water flows into the foundation pit along the side wall of the foundation pit, making the working surface of the foundation pit muddy, making it difficult for workers to construct, and affecting the construction progress; water seepage from the side wall It will also render the slope support ineffective. The water outside the pit seeps into the foundation pit with fine particles, and the soil particles move with the water flow, which produces the quicksand phenomenon. When the size of the soil particles in the soil layer is quite different and there is a lack of a certain particle size, the fine particles will move with the water flow in the gaps between the coarse particles to form a continuous channel, that is, the piping phenomenon. The phenomena of quicksand and piping make the soil layer hollowed out, resulting in uneven ground settlement, and even engineering accidents such as foundation pit slippage and collapse, resulting in loss of manpower and material resources.

When there are multiple underground aquifers on the construction site, due to the objective existence of the down funnel, the burial depth of the tube well for dewatering at the well point must be much greater than the depth of the foundation pit, and the length of the long filter pipe is very long, that is, the water inlet section of the tube well is very long. Long, resulting in the process of foundation pit dewatering not only pumping and draining water within the range of foundation pit dewatering depth, but also extracting water resources from independent aquifers (which can be multiple) below the foundation pit dewatering depth. However, the impact of groundwater in independent aquifers (which can be multiple) below the precipitation depth of the foundation pit on the foundation pit engineering is almost non-existent. At the same time, due to the existence of the tube well, the groundwater in the multi-layer independent aquifer within the depth range of the tube well is penetrated. As we all know, the groundwater in the upper aquifer communicates with the atmosphere, and is greatly affected by human activities, and most of them have been polluted, and the pollution of the groundwater in the upper aquifer is relatively heavier. The polluted groundwater in the upper part will enter the lower aquifer along the tube well under its gravity, so that the originally pure groundwater in the lower part will also be polluted to varying degrees. Therefore, the current method of dewatering foundation pits has not only caused a waste of resources, but also increased the cost of the project, and more seriously, polluted the high-quality groundwater resources in the lower part.

Contents of the invention

The object of the present invention is to provide a well point positioning pumping pipe well, aiming to solve (1) the problem of "drainage and non-drying" of the vertical well point dewatering of foundation pits, that is, in the conventional vertical well point dewatering, the water in the vertical well will disappear as soon as it is pumped, Once stopped, there will still be water during excavation, which will make the working surface of the foundation pit muddy, making it difficult for workers to construct, which will affect the construction progress. The water flow moves in the gaps of coarse particles, which makes the soil layer hollowed out, causing uneven ground settlement, and even causing the foundation pit to slip and collapse, resulting in the loss of manpower and material resources. (2) The protection of water resources in the independent aquifer below the precipitation depth of the foundation pit.

The object of the present invention is to provide a well point positioning pumping tube well, which includes a sand-free tube well section and a water storage tube well section:

Above a certain position of the first water-resisting layer below the dewatering depth of the foundation pit, it is a sand-free well section used to accumulate water sources in the aquifer within the dewatering depth of the foundation pit;

A water storage tube well section that is connected to the sand-free tube well section and is used to store water in the aquifer within the scope of the foundation pit dewatering depth. .

Another object of the present invention is to provide a well point location pumping method, the method comprising:

A well point positioning pumping method, the method comprising:

The well spacing is determined according to the comprehensive permeability coefficient of the soil layer between the groundwater table and the top of the well section of the water storage pipe, the thickness of the aquifer and the drawdown;

The first aquifer below the dewatering depth of the foundation pit is used to use a sand-free well section upwards from a certain position;

The water storage pipe well section is used downwards at a certain position of the first water-resisting layer below the dewatering depth of the foundation pit;

The water source stored in the well section of the water storage pipe is pumped by using the water pumping equipment to fix the water level.

The present invention effectively gathers the water source in the aquifer within the range of the foundation pit dewatering depth by adopting the downwater tube well composed of the sand-free tube well section and the water storage tube well section, and uses the pumping equipment to fix the water level to extract the water source stored in the water storage tube well section, solving the problem of Once the water in the vertical well is pumped, there will be no water, and once it is stopped, there will still be water during excavation, which will make the working surface of the foundation pit muddy, making it difficult for workers to construct, which will affect the construction progress. Phenomenon, the fine particles in the soil move with the water flow in the gap between the coarse particles, causing the soil layer to be hollowed out, causing uneven ground settlement, and even causing the foundation pit to slip and collapse, resulting in the loss of manpower and material resources. At the same time, it solves the problem of "draining and not drying" under the condition of "not dredging and not drying" under the condition of not pumping much water and pumping precipitation without polluting the groundwater source in the independent aquifer below the precipitation depth of the foundation pit. Adopting the method of automatic water pumping at fixed water level will greatly shorten the total time of pumping water and greatly reduce the cost of foundation pit engineering. Today, when water resources are increasingly scarce and water environment and water resources are increasingly valued, it has obvious social and economic benefits.

Description of drawings

Fig. 1 is the structural representation of " dredge not dry " aquifer that prior art provides;

Fig. 2 is the schematic cross-sectional structure diagram of the well point positioning pumping tube well provided by the present invention;

Fig. 3 is a flow chart of the well point positioning pumping method provided by the present invention.

In the figure: 1. Well section without sand tube; 2. Well section with water storage tube; 3. Upper aquifer; 4. Lower aquifer; 5. Foundation pit; 6. Water-resisting layer.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Fig. 2 shows a schematic structural diagram of a well point positioning pumping tube well provided by an embodiment of the present invention. For ease of description, only parts related to the embodiments of the present invention are shown.

The tube well includes:

Located above a certain position of the first water-resisting layer 6 below the foundation pit, the sand-free tube well section 1 is used to accumulate water source in the upper aquifer 3 within the depth range of the foundation pit 5;

Below a certain position of the first water-resisting layer 6 below the foundation pit, it is connected with the sand-free tube well section 1 and is used for storing the water storage tube well section 2 of the water source in the upper aquifer 3 .

In the embodiment of the present invention, the well section 2 of the water storage pipe is a sand-free pipe well section or a steel pipe well section or a solid-wall cement pipe well section. When a sand-free pipe is selected, the outer side must be coated with a cement slurry layer.

In addition, in the embodiment of the present invention, prefabricated double-wall pipes can also be used, or composite wall pipes (a water storage pipe composed of a thin cement mortar solid wall outer layer and a sand-free inner pipe layer). The double-wall pipe is a double-layer ring in section. The outer layer is impermeable and very thin, while the inner layer is relatively thick and can be water-permeable, but the entire double-wall pipe of this combination is impermeable. The sand-free pipe coated with a cement slurry layer on the outside described in the patent of the present invention actually also belongs to this double-wall pipe structure, but the outer layer of cement slurry layer is thinner and the outer wall is made in a different way. When the water pressure is high, it is better to use this kind of prefabricated double wall pipe.

In the embodiment of the present invention, the outer side of the well section 2 of the water storage pipe is filled with a water-stop material layer.

In the embodiment of the present invention, a water stop gasket is provided at the connection of the pipe joints of the well section of the water storage pipe. The determination of the position of the first aquifer below the dewatering depth of the foundation pit needs to consider the influence of the water pressure of the aquifer below it, and it should be ensured that the water in the aquifer does not rush into the water storage tube well section through the sand-free well section.

In the embodiment of the present invention, the criteria for determining a certain position of the first water-resisting layer below the foundation pit precipitation depth are:

According to the size of the water pressure of the aquifer, this position ensures that the water in the aquifer does not rush into the well section of the water storage tube through the well section without sand tube.

Fig. 3 shows the implementation flow of the well point positioning pumping method provided by the embodiment of the present invention.

A well point positioning pumping method, the method comprising:

In step S301, the well spacing is determined according to the comprehensive permeability coefficient, aquifer thickness and drawdown of the soil layer (or aquifer) between the groundwater table and the top of the well section of the water storage pipe;

In step S302, a sand-free well section 1 is used upwards at a certain position of the first water-resisting layer 6 below the dewatering depth of the foundation pit;

In step S303, the water storage pipe well section 2 is used downward at a certain position of the first water-resisting layer 6 below the dewatering depth of the foundation pit;

In step S304, the water source stored in the well section 2 of the water storage pipe is extracted by using the water pumping equipment to fix the water level.

In the embodiment of the present invention, the water storage tube well section 2 is a sand-free tube well section coated with a cement slurry layer on the outside.

In the embodiment of the present invention, the outside of the well section 2 of the water storage pipe is filled with a water-stop material layer.

In the embodiment of the present invention, a certain position of the first aquifer below the dewatering depth of the foundation pit is determined by the principle of ensuring that the water in the aquifer does not seep and surge (through the well section without sand tube) into the well section of the water storage pipe;

In the embodiment of the present invention, the well section of the water storage pipe is formed by connecting multiple sections of water storage pipes, and a water stop gasket is provided at the junction of the pipe sections;

In the embodiment of the present invention, the outside of the sand-free tube well section 1 is filled with graded sand.

In the embodiment of the present invention, the implementation method of using the pumping equipment to fix the water level to extract the water source stored in the well section 2 of the water storage pipe is as follows:

A simple automatic control device can be used to automatically control the working state of the water pump, so that the water source stored in the well section 2 of the water storage pipe can be extracted by the water pump at a fixed water level.

The application principle of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Well point positioning pumping method, that is, the well spacing is determined according to the comprehensive permeability coefficient, aquifer thickness and drawdown of the soil layer (or aquifer) between the groundwater table and the top of the water storage pipe well section. A certain position of the aquifer 6 adopts a sand-free tube well section 1 (also known as a gravel filter pipe) upwards, and a water storage tube well section 2 is used downward to form a downwater tube well. The outside of the sand-free tube well section 1 is filled with graded sand, and the groundwater enters the tube well through the graded sand and the sand-free tube. The water storage tube well section 2 can be a sand-free tube well section coated with a cement slurry layer on the outside, and its outside is filled with water-stopping materials to prevent the water in the lower aquifer 4 from entering the downfall tube well. This section of the tube well actually becomes a water storage reservoir. Water stored in the upper aquifer 3 and infiltrated into the downcomer wells. The length design of this section of water storage pipe well section 2 is mainly based on the amount of water and the pumping capacity of the pumping equipment, so as to ensure that there is a certain storage groundwater space in the impermeable well pipe section after a pumping.

Because under the condition of "draining and not drying", the water flow in the later period is limited, and there will be no water when it is pumped, and there will be water when it is not pumped. This is mainly caused by the water in the pump pipe returning when the pump is stopped. If the returned water basically occupies the space of the storage pipe section, the groundwater outside the tube well can no longer enter the tube well, and the groundwater level of the foundation pit cannot be further reduced, so the groundwater within the depth of the foundation pit cannot be drained. If the second section of the well section of the water storage pipe is too short, the remaining space (called the effective space) is not much after deducting the space occupied by the backflow of the pumped water, and the pump must be stopped and started frequently, which consumes electricity and pumping equipment, and the precipitation effect is poor. ; If the second section of the water storage tube well section is too long, the effective space becomes larger, and the time interval between stopping and starting the pump is also large, which is beneficial to pumping water, but the deepening of the downwater tube well will increase the cost of the tube well, make it difficult to form a deep hole, and cost increase. Therefore, the length of the second section of the water storage pipe well section should be reasonably designed.

In the embodiment of the present invention, the water source in the upper aquifer 3 where the foundation pit 5 is located is effectively collected by using a downwater tube well composed of a sand-free tube well section 1 and a water storage tube well section 2, and the water storage pipe is extracted by using a pumping device (pump) to fix the water level. The water source stored in the well section 2 solves the problem that the water in the vertical well disappears when it is pumped, and there is still water when it is stopped, and there is still water during excavation, which makes the working surface of the foundation pit 5 muddy, and the construction is difficult for workers, which affects the construction progress. The side wall of the foundation pit 5 Water seepage makes the slope support invalid, resulting in quicksand phenomenon, and the fine particles in the soil move with the water flow in the gaps between the coarse particles, which makes the soil layer hollowed out, resulting in uneven ground settlement, resulting in the foundation pit 5 slipping and collapsing, resulting in loss of manpower and material resources question. At the same time, only the groundwater that has an impact on the foundation pit project is extracted, which greatly shortens the total pumping time and reduces the project cost, and because the groundwater in the upper aquifer is isolated from the groundwater in the independent aquifer below the foundation pit, the groundwater in the upper aquifer that is polluted It will not pollute the lower groundwater quality. This has obvious social and economic benefits in today's day when water resources are increasingly scarce and water environment and water resources are increasingly valued.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (1)

1. A well point positioning pumping tube well is characterized in that the tube well comprises a sand-free tube well section and a water storage tube well section: Above a certain position of the first water-resisting layer below the dewatering depth of the foundation pit, it is a sand-free well section used to accumulate water sources in the aquifer within the dewatering depth of the foundation pit; A water storage tube well section that is connected to the sand-free tube well section and is used to store water in the aquifer within the scope of the foundation pit dewatering depth. ; The well section of the water storage pipe is a sand-free pipe well section or a steel pipe well section or a solid-wall cement pipe well section coated with a cement slurry covering layer on the outside, or a combination of a thin cement mortar solid-wall outer layer and a sand-free pipe inner layer. storage pipe; The outside of the well section of the water storage pipe is filled with a water-stop material layer; A water stop gasket is provided at the joint connection of the well section of the water storage pipe; The criteria for determining a certain position of the first water-resisting layer below the precipitation depth of the foundation pit are: According to the size of the water pressure of the aquifer, this position ensures that the water in the aquifer does not rush into the well section of the water storage tube through the well section without sand tube.