CN102033034B - Soil horizontal permeability coefficient measuring instrument - Google Patents

Abstract

The invention discloses a soil horizontal permeability coefficient measuring instrument, which mainly includes a constant pressure water supply system and an infiltration system. The composition of the infiltration system mainly includes a soil sample room vertically set up, a The permeate water distribution water supply pipe and the water collector set outside the sample chamber to hold the permeate water, the sample chamber consists of a cylinder with permeate water outflow holes evenly distributed on the wall, an upper cover tightly connected with the cylinder and It consists of a lower cover, the walls of the distributed water supply pipes are evenly distributed with permeable holes, the upper end is closed, and the lower end of the nozzle passes through the lower cover of the sample chamber to communicate with the stabilized water supply system. The measuring instrument of the present invention can be applied to different soil bodies, and can measure the horizontal permeability coefficient of the soil body in the real state, can be used to measure the horizontal anti-seepage slope of the sample and adapt to the current high water head requirements of high earth-rock dams, and meet the requirements of actual engineering design and Soil permeability characteristics research needs.

Description

Soil horizontal permeability coefficient measuring instrument

technical field

The invention relates to soil permeability coefficient measurement technology, more specifically, relates to a measuring instrument for measuring soil horizontal permeability coefficient, and belongs to the field of geotechnical engineering test research.

Background technique

In geotechnical engineering, permeability is a basic characteristic of soil, generally expressed by permeability coefficient. The permeability coefficient must be measured by a special permeability instrument. The current penetrometers for measuring the permeability of soil are all vertical penetrometers, which can only measure the permeability of the soil perpendicular to the soil layer interface, that is, the vertical permeability coefficient of the soil. However, in practical engineering, water seepage is mainly along the horizontal direction of the soil, and the horizontal permeability of the soil is often more important than the vertical permeability. Therefore, the determination of soil horizontal permeability coefficient has become an urgent problem to be solved.

In order to solve the above problems, scientific and technical personnel in the field have conducted extensive explorations in order to obtain the horizontal permeability coefficient of soil. "Dam Observation and Geotechnical Testing" reported an instrument for measuring the two-way permeability coefficient (Feng Guoming, Fu Qionghua. Instruments and methods for measuring the two-way permeability coefficient of soil. Dam Observation and Geotechnical Testing, 1997, 21(3) : 32-34.), the instrument is transformed on the basis of the triaxial instrument, the sample is square, the water flow direction is vertical, and the measurement of the horizontal permeability coefficient is realized by turning the sample. This method is very difficult to measure the horizontal permeability coefficient of some samples that cannot be molded without the film-supporting cylinder or rubber mold, such as sandy soil samples. The water flow direction of the horizontal permeameter applicable to various rocks and soils should be horizontal, so that it can be consistent with the accumulation of the soil and the soil layer prepared by the sample, and the true permeability coefficient of the horizontal direction of the soil can be measured. Therefore, the instrument cannot measure the horizontal permeability coefficient of the soil in the real state. "Geosynthetics Horizontal Permeability Meter" discloses a measuring instrument for measuring the horizontal permeability coefficient of geosynthetics (Chen Zhiming, Wang Shiming. Geosynthetics Horizontal Permeability Meter. China: CN 200947078Y.2007.9.12.) But the level Penetrometers are not suitable for the determination of the horizontal permeability coefficient of soil.

As far as the inventor knows, before the completion of the present invention, there is no report about a measuring instrument that can be applicable to various soil materials and can measure the soil horizontal direction permeability coefficient under the real state, especially the ability to measure soil The report of the soil horizontal direction permeability coefficient measuring instrument that is resistant to seepage slope and adapts to the current high water head requirements of high earth-rock dams is an urgent problem in this field that has not yet been truly resolved.

Contents of the invention

Aiming at the present situation of soil horizontal permeability coefficient measurement technology, the purpose of the present invention is to propose a measuring instrument which can be applicable to different soils and can measure the horizontal permeability coefficient of soil under the real state, and can be used to measure soil permeability. The horizontal anti-seepage slope of the body sample is suitable for the current high water head requirements of high earth-rock dams, and meets the needs of actual engineering design and soil permeability characteristics research.

In view of the purpose of the above invention, the soil horizontal permeability coefficient measuring instrument proposed by the present invention mainly includes a stabilized water supply system and an infiltration system. The composition of the infiltration system mainly includes a vertical soil sample chamber, a permeation water distribution pipe vertically established in the center of the sample chamber, and a water collector arranged outside the sample chamber to receive the infiltration water. The sample chamber is composed of a cylindrical body with permeable water outflow holes evenly distributed on the wall, an upper cover and a lower cover tightly connected with the cylinder body, the water supply pipe wall is uniformly distributed with permeable holes, the upper end is closed, and the lower end nozzle It passes through the lower cover of the sample chamber and communicates with the water supply system with constant pressure.

On the basis of the above technical scheme, a water supply chamber can also be designed below the sample chamber, and the lower nozzle of the permeable water distribution water supply pipe vertically set up in the center of the sample chamber passes through the lower cover of the sample chamber to communicate with the water supply chamber. The water inlet of the chamber is connected with the stabilized water supply system. The water supply chamber is preferably arranged directly under the sample chamber, and the lower cover of the sample chamber is used as the top cover of the water supply chamber. The sealing connection between the water supply chamber and the sample chamber is best to adopt a flange sealing connection, that is, the cylinder body of the water supply chamber is tightly connected with the cylinder body of the sample chamber through the flange.

In the above technical solution, the water collector holding the infiltrated water is an annular water collection box surrounding the sample chamber, and a water outlet interface is designed on the wall of the annular water collection box. The ring-shaped water collection tank is preferably designed to be composed of a cylindrical cylinder of the sample chamber, a cylindrical cylinder surrounding the outside of the sample chamber and a flat box bottom. The bottom of the box is welded vertically to the cylinder wall below the permeable water outflow hole of the cylinder of the sample chamber. The annular water collection tank can also be designed as a flat-bottomed cone-shaped annular water collection tank composed of a cylindrical cylinder of the sample chamber, a conical cylinder surrounding the outside of the sample chamber and a flat bottom, or it can be designed as a cylindrical cylinder of the sample chamber and a direct A conical ring-shaped water collection box formed by a conical cylinder connected to the permeable water outflow hole of the cylinder of the sample chamber. The water outlet interface is preferably designed on the upper edge of the cylinder forming the annular water collection box to provide a stable outlet water pressure for the sample and facilitate the collection and measurement of the water flow through the sample.

In the above technical solution, the pressure-stabilized water supply system mainly includes a feedwater pump, a water inlet pipe, and a water pressure measuring instrument installed on the water inlet pipe. One end of the water inlet pipe is connected to the water outlet of the feedwater pump, and the other end is connected to the water inlet of the osmosis system. The drive motor of the feedwater pump is controlled by a frequency regulator.

In order to make the water supply pressure of the stabilized water supply system more stable, a water supply regulator can also be designed on the water inlet pipe. The water supply regulator is an airtight container, which communicates with the water inlet pipe through a connecting pipe.

In order to adjust the water supply pressure of the water supply system and measure the water pressure entering the osmosis system more accurately, a water pressure regulating gauge and a water pressure sensor can be installed on the water inlet pipe as a water pressure measuring instrument at the same time. Between the water pump and the water supply regulator, the water pressure sensor is designed between the water supply regulator and the osmosis system. The water pressure sensor is preferably designed near the water supply chamber.

The water supply system of the soil material horizontal permeability coefficient measuring instrument proposed by the present invention is a frequency conversion constant pressure water supply system, which can provide a stable and continuously variable water head for soil samples. The water pressure in the infiltration water distribution pipe located in the center of the sample chamber is equal to the water pressure provided by the frequency conversion constant pressure water supply system, and the water pressure in the water collection tank outside the sample chamber is the hydrostatic pressure at the same level as the water outlet interface. The permeation water flows from the center of the sample to the surroundings under the action of the pressure difference between the center and the outside of the sample chamber to realize the horizontal penetration test. The most prominent feature of the invention is that the water flow direction is completely parallel to the layer of the sample in the sample preparation process, which can simulate the horizontal seepage of the sample soil layer, and realize the measurement of the horizontal permeability coefficient and the research on the resistance to seepage damage in the horizontal direction of the soil.

Compared with the horizontal permeability coefficient measuring instrument of the prior art, the soil horizontal permeability coefficient measuring instrument proposed by the present invention has the following very prominent advantages and technical effects in summary:

1. The soil horizontal permeability coefficient measuring instrument proposed by the present invention has simple structure, convenient operation, clear boundary conditions of water flow, and is convenient for calculating various hydraulic elements in the soil sample. At the same time, since the water flow is from the center to the periphery Radial flow can avoid the problem of concentrated flow between the sample and the side wall of the instrument in the horizontal permeability test of the general square soil sample, and can truly reflect the permeability of the soil sample and the characteristics of resistance to penetration damage .

2. The horizontal permeability coefficient of any soil sample can be easily measured by using the soil horizontal permeability coefficient measuring instrument proposed by the present invention. Since the wall of the sample chamber of the measuring instrument is an annular porous cylinder wall, which can allow fine particles to flow out, the present invention can also be used to measure the critical slope of the soil sample for piping failure, that is, the present invention can also be used as a permeation destruction instrument. .

3. For the water supply system of the soil horizontal permeability coefficient measuring instrument, since the drive motor of the feed water pump is controlled by a frequency regulator, that is, the feed water pump is a frequency conversion feed water pump, and an airbag type water pressure stabilizer is designed on the water inlet pipeline, as well as a water pressure regulator. The meter and the water pressure sensor, combined with the water supply chamber set under the sample chamber of the osmotic system, so that the osmotic water can be stably applied to the soil sample at various hydraulic pressures, and the hydraulic pressure of the osmotic water can be accurately measured. Therefore, this The invention can be used in the research on the resistance to seepage damage of soil samples under the action of a large hydraulic gradient, and meets the needs of actual engineering design.

Description of drawings

Accompanying drawing 1 is the structural representation of an embodiment of the present invention.

Accompanying drawing 2 is A-A sectional structure schematic diagram in accompanying drawing 1.

In the above drawings, the objects identified by the symbols in each diagram are: 1-water inlet; 2-feedwater pump; 3-frequency regulator; 4-water pressure regulator; Water inlet valve; 8- water pressure sensor; 9- water supply chamber; 10 sample chamber; 11- water collector; 12- lower cover of sample chamber; ;15-Water collector cylinder; 16-Sample chamber upper cover; 17-Ring rubber ring; 18-Fixing bolts; 19-Water outlet interface of water collector; .

Detailed ways

An embodiment of the present invention is given below with reference to the accompanying drawings, and the present invention is further described in detail through the embodiment. It must be pointed out that the following examples are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and improvements to the present invention according to the above-mentioned content of the invention. Adjustment, the technical solution obtained in this way should still belong to the protection scope of the present invention.

Example

The soil horizontal permeability coefficient measuring instrument of this embodiment has a structure as shown in accompanying drawings 1 and 2, and is mainly composed of a frequency-converting and stabilizing water supply system and a seepage system.

The frequency conversion stabilized pressure water supply system includes: water inlet 1, water supply pump 2, frequency regulator 3, water pressure regulator 4, water supply regulator 5, water inlet pipe 6, water inlet valve 7 and water pressure sensor 8. The water supply regulator 5 is an airtight container, which communicates with the water inlet pipe 6 through a connecting pipe. The front end of the water inlet 1 of the frequency conversion stabilized water supply system is connected to the water tank or the tap water pipe that provides the water source, and the rear end of the water inlet 1 is connected to the inlet of the feed water pump 2 . The frequency regulator 3 controls the driving motor of the feed water pump 2 to adjust the frequency of the feed water pump. The water pressure regulating gauge 4 located between the feed water pump and the water supply regulator is connected to the water inlet pipe 6 for monitoring and adjusting the required water pressure value. The water inlet valve 7 and the water pressure sensor 8 located between the water supply regulator 5 and the water supply chamber 9 of the osmosis system are connected to the water inlet pipe 6, and are respectively used for controlling the inlet water flow of the osmometer and measuring the water pressure entering the osmosis system.

The permeation system mainly includes a vertically set up sample chamber 10, a permeate water distribution pipe 13 vertically set up in the center of the sample chamber, a water collector 11 set outside the sample chamber for receiving permeate water, and a water collector 11 set up outside the sample chamber. The water supply chamber 9 below and the support 22 supporting the whole osmosis system through the water supply chamber. The sample chamber is composed of a cylindrical body 14 with permeable water outflow holes evenly distributed on the wall, an upper cover 16 and a lower cover 12. The cover is tightly connected. The water supply chamber 9 is composed of a bottom-sealed cylindrical body with the same diameter as the sample chamber cylinder and a top cover as the lower cover 12 of the sample chamber. It is sealed with the sample chamber through its flange, annular rubber ring 17 and fixing bolts 18. connect. The lower part of the water supply chamber is provided with a water discharge connecting pipe 21 equipped with a water discharge valve 20 for emptying the water in the water supply chamber 9 . The water inlet of the water supply chamber communicates with the water outlet of the water inlet pipe 6 of the frequency conversion stabilized water supply system. The distribution water supply pipe 13 is a cecum pipe with permeable holes evenly distributed on the pipe wall and a closed upper end, and the lower end nozzle passes through the lower cover of the sample chamber to communicate with the water supply chamber 9 located below the sample chamber. The water collector 11 for receiving permeated water is an annular water collection box surrounding the sample chamber, which is composed of a cylindrical cylinder 14 surrounding the sample chamber, a cylindrical cylinder 15 surrounding the outside of the sample chamber, and a flat box bottom. The bottom of the box is welded vertically to the sample chamber. On the cylinder wall below the infiltration water outlet hole of the chamber cylindrical cylinder 14, the height of the cylindrical cylinder 15 is basically the same as that of the sample chamber cylinder, and a water outlet interface 19 is designed on the cylindrical cylinder 15 wall.

Adopt measuring instrument of the present invention to measure soil horizontal to permeability coefficient, its measuring process is as follows:

Firstly, the soil samples for the test are prepared according to certain requirements, and then the samples are filled in layers (simulating the filling of soil or the deposition of soil layers) in the sample chamber 10 . When loading the sample, a permeable geotextile is set between the permeable water distribution pipe 13 and the sample, and between the sample and the wall surface of the cylinder body 14 of the sample chamber. A permeable geotextile is set between the permeable water distribution water supply pipe and the sample. On the one hand, the water pressure acts on the sample evenly, and on the other hand, it prevents the fine particles of the sample from entering the distribution water supply pipe and blocking the water outlet; The purpose of laying permeable geotextile between the sample and the wall of the sample chamber is to prevent the loss of sample particles near the wall of the cylinder and play the role of reverse filtration.

After the sample is installed, connect the water inlet 1 of the frequency conversion and pressure stabilized water supply system to the water tank or the tap water pipe to provide water for the water supply pump 2. Set the water pressure value required for the test on the water pressure adjustment table 4, and the frequency regulator adjusts the speed of the drive motor of the feed water pump according to the required pressure value, so that the flow rate flowing through the feed water pump is the same as that of the sample flowing through the sample chamber 10. At this time, the pressure of the water pressure regulator gauge 4 is stable, and then through the pressure stabilizing effect of the voltage stabilizer, the sample is provided with the stable inlet water pressure of the infiltrated water required for measurement.

Open the water inlet valve 7 on the water inlet pipe of the frequency conversion stabilized water supply system, and the water is injected into the water supply chamber 9, and at the same time enters the infiltration water supply distribution pipe 13 located in the center. Since the water supply chamber 9 is entirely sealed, the water pressure in the water inlet pipe 6 is directly transmitted to the permeate distribution water supply pipe. That is, the water pressure in the water inlet pipe 6 is equal to the water pressure in the water supply chamber 9 and the permeated water distribution water supply pipe 13 , which is measured by the water pressure sensor 8 connected to the water inlet pipe 6 . The water flows horizontally and radially in the sample under the action of the pressure difference between the permeated water distribution water supply pipe and the water collection tank 11 arranged outside the sample chamber, enters the sample from the permeated water distribution water supply pipe 13, and flows from the sample chamber 10 The infiltration water evenly distributed on the wall surface of the cylinder body 14 flows out and collects in the water collection tank 11. The water pressure at the sample infiltration overflow outlet is the hydrostatic pressure in the water collection tank. The permeation flow through the sample can be calculated from the water volume measured by the water outlet interface 19 arranged on the wall of the water collection box 15 and the water collection time. When the water head at the inlet and outlet of the sample is known and the flow rate is known, the horizontal permeability coefficient of the sample can be calculated.

The invention can also be used to measure the horizontal permeability coefficient of other porous medium material bodies.

Claims (10)

1. A kind of soil body horizontal permeability coefficient measuring instrument mainly comprises steady-pressure water supply system and seepage system, it is characterized in that the formation of seepage system mainly comprises the soil body sample room (10) that vertically sets up, vertically sets up in test bed The infiltration water distribution water supply pipe (13) in the center of the sample chamber and the water collector (11) arranged outside the sample chamber to hold the infiltration water, the sample chamber consists of a cylinder with infiltration water outflow holes evenly distributed on the wall ( 14) Composed of an upper cover (16) and a lower cover (12) that are airtightly connected to the cylinder body, the pipe wall of the distribution water supply pipe is evenly distributed with permeation holes, the upper end is closed, and the lower end nozzle passes through the lower cover of the sample chamber Connected to the regulated water supply system. 2. The soil horizontal permeability coefficient measuring instrument according to claim 1 is characterized in that a water supply chamber (9) is designed below the sample chamber (10), and the lower nozzle of the distribution water supply pipe passes under the sample chamber The cover is communicated with the water supply chamber, and the water inlet of the water supply chamber is communicated with the pressure-stabilized water supply system. 3. The soil horizontal permeability coefficient measuring instrument according to claim 2, characterized in that the water supply chamber is directly arranged below the sample chamber, and the lower cover of the sample chamber is used as the top cover of the water supply chamber. 4. The soil horizontal permeability coefficient measuring instrument according to claim 3, characterized in that the water supply chamber and the sample chamber are sealed and connected by flanges. 5. The soil horizontal permeability coefficient measuring instrument according to claim 1, characterized in that the water collector holding infiltration water is an annular water collection box surrounding the sample chamber, and a water outlet interface is designed on the wall of the annular water collection box (19). 6. soil horizontal permeability coefficient measuring instrument according to claim 5, is characterized in that ring-shaped water collecting tank is made of sample room cylindrical shell (14), around the cylindrical shell outside the sample room cylindrical shell ( 15) It is composed of a plane groove bottom, and the groove bottom is vertically welded to the cylinder wall below the infiltration water outflow hole of the cylindrical cylinder body of the sample chamber. 7. The soil horizontal permeability coefficient measuring instrument according to claim 6, characterized in that the water outlet interface is designed on the upper edge of the annular water collection tank cylinder. 8. The soil horizontal permeability coefficient measuring instrument according to any one of claims 1 to 7, characterized in that the pressure-stabilized water supply system mainly includes a water supply pump (2), a water inlet pipe (6) and a water pressure on the water inlet pipe As for the measuring instrument, one end of the water inlet pipe is connected with the water outlet of the feedwater pump, and the other end is connected with the water inlet of the osmosis system, and the driving motor of the feedwater pump (2) is controlled by the frequency regulator (3). 9. The soil horizontal permeability coefficient measuring instrument according to claim 8, characterized in that a water supply regulator (5) is designed on the water inlet pipe (6), and the water supply regulator is a closed container, which is The water pipe is connected. 10. The soil horizontal permeability coefficient measuring instrument according to claim 9, characterized in that the water pressure measuring instrument arranged on the water inlet pipe (6) is a water pressure regulator (4) and a water pressure sensor (8), The water pressure regulator is designed between the water feed pump (2) and the water supply regulator (5), and the water pressure sensor is designed between the water supply regulator (5) and the osmosis system (9).

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