CN105821830A - Permeation increase siphon drainage system for low-permeability soil slope - Google Patents

Abstract

The invention relates to the technical field of low-permeability geotechnical engineering drainage, in particular to a seepage-increasing siphon drainage system for low-permeability soil slopes, and is particularly suitable for engineering drainage in low-permeability water-rich formations. It consists of a permeable concrete fracturing injection system and a siphon drainage system. For loess slopes with low permeability and collapsibility, the permeable concrete is pressed into the low-permeability loess landslide to form a high-permeability network channel and expand a single siphon drainage The hole creates a drop funnel for the area of influence. Increase the drainage efficiency through the high-permeability permeable network, rely on the principle of high-lift siphon, automatically and efficiently discharge the excess groundwater in the slope in real time, and can control the groundwater level of the slope below the safe water level without any external power, with low cost and high efficiency. The advantages.

Description

A seepage-enhancing siphon drainage system for low-permeability soil slopes

technical field

The invention belongs to the technical field of low-permeability soil drainage, in particular to a drainage method for forming a high-permeability network by pressing in permeable materials, and is especially suitable for drainage of foundations and side slopes composed of low-permeability soil.

Background technique

In the field of foundation treatment and landslide prevention and control, the timely discharge of groundwater contained in the soil is the key to the success of engineering treatment. However, for soils with very low permeability, the drainage process often takes a long time, which greatly affects the progress of the project. Increasing the drainage of low-permeability soils per unit time has become the main way to solve this problem.

At present, in the field of foundation treatment, sand wells and plastic drainage plates are commonly used as drainage channels, and the pore water pressure is increased by means of surcharge preloading, and a large hydraulic gradient is formed between the soil and the drainage channel, which is discharged as groundwater. power. This way construction time is long, and the process is complicated. However, in slope treatment, gravity drainage holes are often used for drainage, which is indeed often troubled by blockage of drainage holes. In order to solve this problem, some scholars use the siphon method to drain the slope. Its advantage is that it can realize the automatic control of the siphon start, it is not easy to block the hole, and the drainage depth is relatively large. However, this method still has some problems in low permeability soil. Due to the low permeability of the soil, the groundwater flow into the siphon system collection pipe is small, the siphon pause time is long, and there is a risk of failure. In addition, low permeability often leads to high hydraulic gradient, which limits the scope of influence of the siphon drainage drop funnel. It is necessary to solve this problem by densely arranging siphon drainage holes with low holes, which greatly increases the engineering volume. Therefore, it is necessary to invent a method and a device to improve the drainage efficiency and influence range of low-permeability soil in combination with a siphon drainage system.

Contents of the invention

Aiming at the shortcomings of the siphon drainage method in the prior art, such as low drainage efficiency in low-permeability soil, small influence range, and the need for a large amount of manpower and material resources, the technical problem to be solved by the patent of the present invention is to use permeable materials to pressurize the low-permeability soil. Split into a network to form a highly permeable water-permeable network. The anti-permeability technology can not only increase the internal drainage area of low-permeability soil and improve drainage efficiency, but also can play a role in internal reinforcement of the drainage area, has a filtering effect on soil particles, and ensures that the soil will not be eroded destroy. Combined with the characteristics of siphon automatic drainage, automatic recovery, long-term stability and effectiveness, it realizes efficient, stable and safe drainage of low-permeability soil. Soil types with high groundwater content and low permeability, such as loess, silty clay, etc.

The technical solution adopted by the present invention to solve its technical problems is:

A seepage-increasing siphon drainage system for low-permeability soil slopes, characterized in that: the seepage-enhancing siphon drainage system for low-permeability soil slopes includes a fracturing injection system and a siphon drainage system, and the pressurization The crack injection system includes a high-pressure pump, drilling casing, and permeable concrete. The siphon drainage system includes a siphon pipe and a sump. The siphon drainage system is a high-lift siphon drainage system with a head higher than 10m, which is used to automatically Start the siphon, discharge the groundwater in the formation in real time, and control the groundwater level below a safe water level.

The drilling casing of the fracturing injection system consists of a permeable concrete pumping port, an outer casing joint, an inner casing plug, an inner casing, an outer casing, a directional injection pipe head, and a water-permeable water collection pipe. The drilling casing passes through Drill the hole to install the directional injection pipe head at the predetermined position in the low-permeability soil slope, adjust the position of the directional injection pipe head to ensure the injection direction of the permeable concrete. The high-pressure pump is connected to the pumping port of the permeable concrete to inject the permeable concrete between the inner casing and the outer casing, and then inject the permeable concrete from the directional injection pipe head into the low-permeability soil slope, and the permeable concrete develops along the weak area of the soil, While fracturing the rock and soil in the formation, it can fill the entire fracture space and solidify to form a high-permeability drainage network in space. After the permeable concrete solidifies, remove the outer casing joint and inner casing plug of the drilling casing to make the drilling casing The inner casing of the siphon is connected with the siphon of the siphon drainage system, and the water is reversely poured into the siphon and enters the water collection pipe at the lower end, lowering the elevation of the lower end of the siphon pipe, so that the elevation of the lower end of the pipe is lower than the elevation of the upper end of the pipe, and the initial siphon is realized, and the groundwater passes through the space height The permeable drainage network enters the directional injection headers, passes through pervious concrete and permeable headers into the inner casing, and drains the water to the sump through siphons.

The described seepage-increasing siphon drainage system for low-permeability soil slopes is characterized in that: the permeable concrete has a permeability coefficient of 0.01-0.02m/d, and a small amount of cement slurry is added such as graded aggregate to form a high The permeable structure with porosity acts as a channel for groundwater seepage. After being pressed into the loess, a drainage network centered on the water collection pipe and diffused to the surroundings is formed.

The drilling casing is a double casing structure, and there is a permeable concrete injection channel between the inner casing and the outer casing.

The siphon adopts a polyurethane (PU) siphon with an inner diameter of less than 5 mm, which can form a slug flow during the siphon flow without air accumulation.

The maximum available pressure of the high-pressure pump is 10MPa, and the pressure of the high-pressure pump is determined according to the position of the directional injection pipe head, the thickness of the overlying soil layer and the spacing of the drainage holes involved.

The inner casing of the drilling casing is made of PVC pipe, which is also used as a channel for placing the siphon.

The outer casing of the drilling casing is made of steel pipe, and the end of the pipe is provided with a shaped pipe head, and the directional pipe head serves as a drill bit at the same time during the drilling process.

The beneficial effects of the present invention are mainly manifested in:

1. The slope drainage system of the present invention uses the high-lift siphon principle to automatically and efficiently discharge excess groundwater in the slope in real time, and can control the groundwater level of the slope below the safe water level without any external power;

2. The present invention presses permeable concrete into the low-permeability loess landslide through high pressure to form a high-permeability network channel and expand the influence range of a single siphon drainage hole to produce a descending funnel;

3. The high-permeability network channel formed by the present invention has two functions of drainage and reinforcement, which can increase the shear strength of the soil while reducing the groundwater level, and improve the safety factor of the slope;

4. The present invention is specially aimed at the loess slope with low permeability and collapsibility, increases the drainage efficiency through the high permeability permeable network, relies on the siphon drainage technology for automatic drainage, and has the advantages of low cost and high efficiency.

Description of drawings

Fig. 1 is an overall diagram of the technical principle of the present invention;

Fig. 2 is the axial sectional view of the drilling casing of the present invention;

Fig. 3 is a radial sectional view of the drilling casing of the present invention;

In the figure: 1 underground water level; 2 space high permeability drainage network; 3 bored casing; 4 low permeability soil slope; Pipe plug; 10 internal casing; 11 external casing; 12 directional injection pipe head; 13 water-permeable water collection pipe; 14 permeable concrete.

detailed description

The invention provides a seepage-increasing siphon drainage system for low-permeability soil slopes. The seepage-enhancing siphon drainage system for low-permeability soil slopes includes a fracturing injection system and a siphon drainage system. The fracturing The injection system includes a high-pressure pump, a borehole casing 3, and permeable concrete 14; the siphon drainage system includes a siphon 5 and a sump 6, and the siphon drainage system is a high-lift siphon drainage system with a head higher than 10m, used for When lifting, the siphon is automatically activated to discharge the groundwater in the formation in real time, and the groundwater level is controlled below a safe water level. The drilling casing 3 of the fracturing injection system consists of a permeable concrete pumping port 7, an outer casing joint 8, and an inner casing plug 9 , an inner casing 10, an outer casing 11, a directional injection nozzle 12, and a water-permeable water collection pipe 13. The drilled casing 3 installs the directional injection nozzle 12 at a predetermined position in the low-permeability soil slope 4 through drilling , adjust the position of the directional injection pipe head 12 to ensure the injection direction of the permeable concrete 14, the high-pressure pump is connected to the pumping port 7 of the permeable concrete, inject the permeable concrete 14 between the inner casing 10 and the outer casing 11, and then inject the permeable concrete 14 The low-permeability soil slope 4 is injected from the directional injection pipe head 12, and the permeable concrete 14 develops along the weak area of the soil body, and can fill the entire crack space and solidify while fracturing the formation rock and soil, forming a space high-permeability drainage network 2, After the permeable concrete 14 is solidified, remove the outer casing joint 8 and the inner casing plug 9 of the drilling casing 3, connect the inner casing 10 of the drilling casing 3 with the siphon pipe 5 of the siphon drainage system, and pour water into the The siphon pipe 5 enters the water collecting pipe 13 at the lower end, lowers the elevation of the lower end of the siphon pipe 5 so that the elevation of the lower end of the pipe is lower than the elevation of the upper end of the pipe, and realizes the initial siphon. The permeable concrete 14 and the permeable water collecting pipe 13 enter the inner casing 10, and then the water is discharged to the sump 6 through the siphon 5.

Claims (5)

1. the anatonosis siphon drainge system for hypotonicity slight slope, it is characterized in that: the described anatonosis siphon drainge system for hypotonicity slight slope includes that pressure break injected system and siphon drainge system, described pressure break injected system include high-pressure pump, borehole casing (3), pervious concrete (14)；nullDescribed siphon drainge system includes siphon (5)、Collecting-tank (6)，Siphon drainge system is the high-lift siphon drainge system that lift is higher than 10m，For automatically starting siphon when groundwater table rise，Discharge subsoil water in stratum in real time，Controlling groundwater level is below a safety level，The borehole casing (3) of pressure break injected system is by pervious concrete pumping outlet (7)、Trocar sheath joint (8)、Inner sleeve pipe close (9)、Inner sleeve (10)、Outer sleeve (11)、Orientation injects tube head (12)、Water penetration collector pipe (13) forms，Orientation is injected tube head (12) by boring and is arranged on the precalculated position in hypotonicity slight slope (4) by borehole casing (3)，Adjust orientation and inject the position of tube head (12)，Ensure the injection direction of pervious concrete (14)，High-pressure pump is connected with pervious concrete pumping outlet (7)，Pervious concrete (14) is injected between inner sleeve (10) and outer sleeve (11)，Then pervious concrete (14) is injected tube head (12) from orientation and inject hypotonicity slight slope (4)，Pervious concrete (14) develops along soil body weakness zone，At fracturing stratum ground simultaneously，Whole crevice space can be full of and solidify，Form space high osmosis drainage network (2)，The trocar sheath joint (8) of borehole casing (3) is taken off after pervious concrete (14) solidification、Inner sleeve pipe close (9)，The inner sleeve (10) of borehole casing (3) is made to be connected with the siphon (5) of siphon drainge system，By watery vomiting to pouring into siphon (5). and enter the collector pipe (13) of lower end，Reduce siphon (5) pipe lower end elevation，Make the pipe lower end elevation elevation less than pipe upper end，Realize initial siphon，Subsoil water enters orientation by space high osmosis drainage network (2) and injects tube head (12)，Inner sleeve (10) is entered again by pervious concrete (14) and water penetration collector pipe (13)，By siphon (5), water is discharged to collecting-tank (6) again.

2. according to the anatonosis siphon drainge system for hypotonicity slight slope described in claim 1, it is characterised in that: described pervious concrete (14), infiltration coefficient reaches 0.01～0.02m/d.

3. according to the anatonosis siphon drainge system for hypotonicity slight slope described in claim 2, it is characterized in that: described borehole casing (3) is double-tube structure, be pervious concrete (14) injection channel between inner sleeve (10) and outer sleeve (11).

4. according to the anatonosis siphon drainge system for hypotonicity slight slope described in claim 3, it is characterised in that: described siphon (5) uses the internal diameter polyurethane siphon less than 5mm.

5. according to the anatonosis siphon drainge system for hypotonicity slight slope described in claim 4, it is characterized in that: the inner sleeve (10) of described borehole casing (3) uses PVC, the outer sleeve (11) of described borehole casing (3) uses steel pipe.