CN109342150B - Test device and method for gas-containing soil sample consolidation test and permeation test - Google Patents

Abstract

The invention discloses a test device and a method for a gas-containing soil sample consolidation test and a permeability test. It includes a base, a middle ring is connected to the top of the base, an upper ring is installed on the top of the middle ring, a rubber water bag is provided at the lower part of the middle ring, and a rubber water bladder is installed on the outside of the middle ring. A water injection pipe is installed, and a three-way valve A is connected to the water injection pipe. The three-way valve A is connected to the water inlet pipe and the water outlet pipe. A pressure sensor B is installed on the water outlet pipe. There are water flow channels B and water flow channels C and water flow channels B in the middle of the middle ring. There is a pressure sensor A in a sealed connection, and the water flow channel C is connected to a three-way valve B through the pipe A. The three-way valve B is connected to the flow measuring pipe and the water supply device through the pipe respectively; a piston is installed in the upper ring, and a top cap is installed on the top of the piston. , there is a drainage pipe at the bottom of the top cap, and the drainage pipe is connected to the liquid measuring pipe through pipe B; there is an exhaust pipe at the top of the top cap. The invention is suitable for gas-containing soil penetration and consolidation tests, has the advantages of novel structure, low cost, etc., and improves the measurement accuracy of the test.

Description

A test device and method for consolidation test and permeability test of gas-containing soil samples

Technical field

The invention relates to the technical field of geotechnical engineering geotechnical testing, and in particular to a testing device and method for consolidation testing and permeability testing of gas-containing soil samples.

Background technique

Gas-bearing soil generally refers to soil with a closed gas phase, and the gas phase exists in the form of free, dissolved or gas-water compounds. It is generally distributed at the bottom of lakes, estuaries, valley bottoms, deltas, seabeds and shallow areas with relatively rich oil and gas resources. in the formation. Among them, gas-bearing soil that is rich in shallow gas and whose gas phase exists in the free bubble phase generally has the characteristics of high water content, saturated gas phase dissolution and gas pressure higher than atmospheric pressure, small permeability coefficient, and being in a metastable equilibrium state. In the field of geotechnical engineering, little is known about this kind of gas-bearing soil with special properties and engineering properties that are different from ordinary saturated soil and unsaturated soil. One of the main difficulties lies in the lack of dedicated testing equipment. The general consolidation permeability test device is only suitable for the measurement of consolidation deformation parameters and penetration parameters of general saturated soil. Since it can only measure the drainage volume during the consolidation process, but cannot measure the exhaust volume during the consolidation process, therefore It cannot be applied to the consolidation and penetration test of aerated soil. Chinese Patent No. ZL201820038132.7 discloses a consolidation test device for air-containing soil, including a bracket, a pressure cylinder, a piston, a top cap, a porous plate, a guide rod, a displacement sensor, a total stress sensor, a water vapor measurement device, and a device to be measured. The pore water pressure measuring device, water inlet, conduit and pressure cylinder on the upper and lower surfaces of the soil sample are fixed on the bracket; the piston is placed in the pressure cylinder; the guide rod is set at the bottom of the piston; the displacement sensor is placed at the bottom of the bracket and connected to the guide rod; the top cap and porous The plate is set on the consolidation chamber from top to bottom; the total stress sensor is set on the upper surface of the piston; the water vapor measuring device is set on the top cap; the pressure cylinder is set with a water inlet; the piston is set with a conduit; the water inlet and pressure The chambers are connected and connected to external pressurizing equipment; the pore water pressure measuring devices on the upper and lower surfaces of the soil sample to be tested are respectively connected to the upper and lower surfaces of the soil sample to be tested. This device can be applied to gas-containing soil, and can perform gas sealing and water vapor separation during the consolidation process and independent measurement; however, this device cannot realize the permeability test of gas-containing soil, and the operation is relatively complicated, which is not conducive to the gas-containing soil. Accurate and rapid measurement of consolidation test and permeability test of air and soil samples.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a test device and method for the consolidation test and permeability test of gas-containing soil samples, which is suitable for conducting permeability tests and consolidation of gas-containing soil at the same time. The test can also overcome the influence of the piston side wall friction error during the consolidation process. It has the advantages of novel structure and low test cost, and at the same time improves the measurement accuracy of the test.

The object of the present invention is achieved through the following technical solutions:

A test device for consolidation test and permeability test of gas-containing soil samples, including a base, a middle ring, an upper ring, a piston, a top cap, a liquid measuring tube, a flow measuring tube and a water supply device. The top of the base is tightly connected with a middle ring , the upper ring is installed in a sealed manner on the top of the middle ring. The internal cavity of the middle ring includes an upper soil sample cavity and a lower water bladder placement cavity. A rubber water bladder is placed in the lower water bladder placement cavity. The rubber water bladder has a structure similar to that inside the water bladder. The lower part of the middle ring has a water flow channel A that is connected to the pipe head of the rubber water bag. A water injection pipe is installed on the outside of the middle ring and is tightly connected to the water flow channel A. A three-way valve is connected to the water injection pipe. A. The three-way valve A is also connected to a water inlet pipe and an outlet pipe, and a pressure sensor B is installed on the outlet pipe; there is a water flow channel B and a water flow channel C in the middle of the middle ring that are higher than the height of the rubber water bag, so The water flow channel B is connected to a pressure sensor A in a sealed manner, and the water flow channel C is connected to a three-way valve B through the pipe A. The three-way valve B is also connected to the flow measuring pipe and the water supply device through the pipes; inside the middle ring A permeable stone is placed on the top of the rubber water bag in the cavity. A piston is installed in the internal cavity of the upper ring. There are several vertical channels running through the piston. A top cap is installed on the top of the piston. There is a top cap cavity inside the cap that is connected to the vertical channel. There is a drainage pipe connected to the side of the top cap cavity on the lower side wall of the top cap. The drainage pipe is connected to the liquid measuring pipe through pipe B. A stopper is installed on pipe B. Water clamp; the top of the top cap is provided with an exhaust pipe connected to the top of the top cap cavity, the top of the top cap is provided with an exhaust pipe connected with the exhaust pipe, and the exhaust pipe is provided with an exhaust valve.

In order to better implement the present invention, the present invention also includes a computer data processing system, and the pressure sensor A and pressure sensor B are respectively electrically connected to the computer data processing system.

Preferably, the bottom of the piston is provided with a drainage pressure groove connected to all vertical channels. A porous plate is placed below the drainage pressure groove at the bottom of the piston. Filter paper is also placed between the porous plate and the bottom of the piston.

Preferably, a drain pipe connected to the exhaust pipe is provided on the outer wall of the top of the top cap, and a drain valve is installed on the drain pipe.

Preferably, a carrying head is provided on the top plane of the top hat.

Preferably, the height of the top plane of the permeable stone is higher than the height of the water flow channel B, and at the same time, the height of the top plane of the permeable stone is higher than the height of the water flow channel C.

Preferably, three bolts at 120° to each other are connected between the upper ring and the base to compress and fix the middle ring. There is an annular groove A in the center of the top of the base, and the bottom of the middle ring is plugged into the base. In the annular groove A, an ○-shaped sealing ring B is installed between the bottom of the middle ring and the top of the base; the bottom of the upper ring is provided with an annular groove B, and the top of the middle ring is inserted into the ring of the upper ring. In the annular groove B, an ○-shaped sealing ring C is installed between the top of the middle ring and the bottom of the upper ring.

Preferably, the bottom of the top cap is provided with an annular groove C, the top of the piston is fitted and inserted into the annular groove C of the top cap, and a ○ is installed between the top of the piston and the bottom of the top cap. Type sealing ring A, and several ○-shaped sealing rings A are installed on the outer wall of the lower part of the piston; the top surface of the top cap cavity of the top cap forms an angle of 15° with the horizontal plane.

The ○-shaped sealing ring A, ○-shaped sealing ring B, and ○-shaped sealing ring C of the present invention are all technical contents well known to the public in this technical field. They are rubber rings with a circular cross-section, and their overall appearance is ○-shaped. , so it is called ○-shaped sealing ring. It is mainly used between mechanical parts to prevent the leakage of liquid and gaseous media. It can also be used as a dynamic sealing element for axial reciprocating motion and low-speed rotational motion; ○-shaped sealing ring can also It is called a circular sealing ring and serves as a seal between two parts.

A test method for consolidation test and permeability test of gas-containing soil samples, including a test device, and the method steps are as follows:

A. Install the test device: Place the base on the leveling consolidator and adjust the base to a horizontal position. Install the middle ring to the top of the base that has been coated with Vaseline. Before installing the middle ring, between the top of the base and the bottom of the middle ring Pad the ○-shaped sealing ring B to seal; place the rubber water bladder in the lower water bladder placement cavity in the middle ring so that the pipe head of the rubber water bladder is tightly connected with the water flow channel A. Install pressure on the outlet pipe at A of the three-way valve Sensor B, connect the pressure sensor B to the computer data processing system, then open the water inlet valve of the three-way valve A, turn the base and the middle ring sideways, so that the water flow channel A is vertically upward, use a medical syringe to pass through the three-way valve A Slowly inject degassed water into the rubber water bag through the water inlet to discharge the air in the rubber water bag. When the rubber water bag is completely filled with water, close the water inlet valve of the three-way valve A; then reset the base together with the middle ring. And keep the outlet pipe at the three-way valve A and the pressure sensor B in a connected state; seal the pipe A with the water flow channel C in the middle ring, install the three-way valve B on the pipe A, and separate the water supply device and the flow measuring pipe. Connected to the other two interfaces of the three-way valve B through the pipeline; seal the pressure sensor A at the water flow channel B in the middle ring, and connect the pressure sensor A to the computer data processing system; close the upper ring sealing cover on the top of the middle ring, and Place an ○-shaped sealing ring C between the upper ring and the middle ring to seal it. Use three bolts at 120° to each other to connect and fix the upper ring and the base. Tighten all the bolts to compress the middle ring; then put the rubber water bag on top of the middle ring in turn. Moisten the water-saturated permeable stone and soaked filter paper, and put the prepared air-containing soil sample into the upper soil sample cavity on the upper part of the rubber water bag, and let it stand for at least 36 hours until the air-containing soil sample consolidates and settles under its own weight. , suck away the water precipitated on the surface of the aerated soil sample, place a porous plate on the upper surface of the aerated soil sample, and then put a layer of soaked filter paper; lift and slide the piston in the upper ring, and place the space between the outer wall of the piston and the inner wall of the upper ring Place several ○-shaped sealing rings A on the contact surface to seal, and make the lower surface of the piston contact the porous plate. At the same time, apply an appropriate amount of Vaseline on the outer wall of the piston; cover the top cap, and drain the water from the side of the top cap through pipe B. The pipeline is connected to the measuring liquid pipe. Open the exhaust valve of the exhaust pipe and loosen the water stop clamp on pipe B. Inject degassed water into the measuring liquid pipe until the water overflows from the exhaust pipe of the top cap, and then stops. Inject water and close the exhaust valve of the exhaust pipe; place the test device that has been installed with aerated soil samples at the predetermined position of the pressurization platform. The predetermined position of the pressurization platform is equipped with a pressurization device and a dial indicator. The pressurization device has For the pressure rod, contact the bottom end of the pressure rod of the pressure device with the load-bearing head at the top of the top cap, and adjust the dial indicator so that the dial indicator is exactly at the center of the top of the pressure rod;

B. Before formal loading, apply a pre-pressure load through the pressurizing device so that the pressure exerted on the gas-containing soil sample displayed by pressure sensor B is 1kPa. After stabilization, reset the dial indicator to zero to measure the gas content at this time. Based on the height H of the soil sample, calculate the void ratio e ₀ , which is the initial void ratio before the test, and note that the reading of the measuring pipe at this time is V ₁ ;

C. Apply an external load through the pressurizing device so that the pressure exerted on the air-containing soil sample displayed by pressure sensor B is 2kPa. Record the readings of the dial indicator at each time node. At the same time, observe the pressure in the air-containing soil sample through pressure sensor A. For the dissipation of pore pressure, keep the consolidation pressure of 2kPa unchanged until the pore pressure in the aerated soil sample dissipates to zero;

D. When the pore pressure dissipates to zero, the deformation amount h _i1 of the soil sample is obtained based on the dial indicator reading. Then the height of the air-containing soil sample after consolidation under this level of load is _Hi1 = Hh _i1 . The load of this level is the value of step C. 2kPa consolidation pressure, passed Obtain the void ratio of the air-containing soil sample at this time, and at the same time read the reading V ₂ of the liquid measuring tube at this time, V _w + V _g = V ₂ - V ₁ , where V _w is the air-containing soil sample of this level of load. The volume of discharged water, V _g is the volume of discharged gas from the air-containing soil sample of this level of load; open the exhaust valve of the exhaust pipe on the upper part of the top cap until the gas accumulated at the top of the top cap cavity of the top cap is completely eliminated , close the exhaust valve of the exhaust pipe, and record the volume reading in the liquid measuring pipe at this time. The change before and after the exhaust is △V, that is, △V = V _g . In this level of load consolidation test, the air-containing soil The volume of gas discharged from the sample is V _g . This level of load consolidation test is the test under the 2kPa consolidation pressure of step C. Correspondingly, the volume of discharged water from the air-containing soil sample in this level of load consolidation test is V _w =V ₂ -V ₁ -ΔV;

E. Penetration test: After the consolidation test is completed, the permeability test of the air-containing soil sample can be carried out. Use a water-stop clamp to cut off the drainage pipe to drain water outwards. Open the drain valve on the drainage pipe at the top of the top cap to allow access to the inside of the top cap. The water in the top cap cavity can be drained freely; adjust the three-way valve B and inject degassed water into the flow tube through the water supply device so that the water head height in the flow tube is 1m. Stop water supply after the water head in the tube stabilizes; adjust the three-way Valve B allows the water in the flow tube to slowly penetrate into and pass through the aerated soil sample. When water is discharged from the drain pipe at the top of the top cap, start to measure the initial water head height h ₁ and the corresponding time t ₁ in the flow tube. After a period of time, record the water head height h ₂ and the corresponding time t ₂ in the flow tube again. When the water head height in the flow tube finally remains unchanged, record the water head height h and the corresponding time t in the flow tube at that moment; repeat The above operations of the permeability test are performed M times. During each permeability test, the water head height in the flow measuring tube needs to be changed. Finally, the permeability coefficient of the air-containing soil sample at this time can be calculated according to the saturated soil change head permeability test method in the conventional geotechnical test. ;

F. Continue to apply external load through the pressurizing device, repeat the above steps C to E, and obtain the consolidation test and permeability test result data of the gas-containing soil sample under various levels of consolidation pressure.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The present invention can perform both the consolidation test of aerated soil and the permeability test of aerated soil. At the same time, the invention also overcomes the influence of the frictional resistance of the piston side wall of the existing device, can more accurately measure the consolidation pressure acting on the aerated soil sample, and has the advantages of novel structure and convenient operation.

(2) The present invention is not only suitable for conducting permeability tests and consolidation tests in aerosol soil at the same time, but also can overcome the influence of the friction resistance error of the piston side wall during the consolidation process. It has the advantages of novel structure and low test cost, and at the same time improves the efficiency of the test. The measurement accuracy of the test.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a schematic structural diagram of the drainage pressure groove at the bottom of the piston of the present invention.

Among them, the names corresponding to the reference signs in the accompanying drawings are:

1 base, 2 rubber water bladder, 3 three-way valve A, 4 pressure sensor A, 5 drain valve, 6 upper ring, 7○ sealing ring A, 8 top cap, 81 top cap cavity, 9 load-bearing head, 10 middle ring, 11 air-containing soil sample, 12 porous plate, 13 flow measuring tube, 14 liquid measuring tube, 15 exhaust pipe, 16 water supply device, 17 bolt, 18 piston, 19 pressure sensor B, 20 pipe A, 21 water flow channel B, 22 Water flow channel C, 23 three-way valve B, 24 drainage pipe, 25 permeable stone, 26○ type sealing ring B, 27 vertical channel, 28 drainage pressure groove, 29 water stop clamp, 30 water flow channel A, 31 pipe B, 32 ○ type sealing ring C, 33 computer data processing system.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples:

Example

As shown in Figures 1 to 2, a test device for consolidation test and permeability test of air-containing soil samples includes a base 1, a middle ring 10, an upper ring 6, a piston 18, a top cap 8, a measuring pipe 14, The flow measuring tube 13 and the water supply device 16 are connected to the middle ring 10 at the top of the base 1 in a sealed manner. The upper ring 6 is installed in a sealed manner at the top of the middle ring 10. The internal cavity of the middle ring 10 includes an upper soil sample cavity and a lower water bladder placement cavity. The lower water bladder is placed A rubber water bladder 2 is placed in the cavity. The rubber water bladder 2 has a pipe head connected to the inner cavity of the water bladder. The lower part of the middle ring 10 has a water flow channel A30 connected to the pipe head of the rubber water bladder 2. The middle ring 10 is equipped with a water flow channel A30 on the outside. The water injection pipe is airtightly connected to the water flow channel A30. The water injection pipe is connected to a three-way valve A3. The three-way valve A3 is also connected to a water inlet pipe and a water outlet pipe. A pressure sensor B19 is installed on the water outlet pipe. The middle part of the middle ring 10 has a water flow channel B21 and a water flow channel C22 that are higher than the rubber water bladder 2. The water flow channel B21 is connected to a pressure sensor A4 in a sealed manner. The water flow channel C22 is connected to a three-way valve B23 through the pipe A20, and the three-way valve B23 also passes through The pipelines are connected to the flow measuring pipe 13 and the water supply device 16 respectively. A permeable stone 25 is placed on the top of the rubber water bladder 2 in the internal cavity of the middle ring 10. A piston 18 is installed in the internal cavity of the upper ring 6. There are several vertical channels 27 running through the piston 18. The top of the piston 18 is sealed and installed with The top cap 8 has a top cap cavity 81 connected to the vertical channel 27 inside. The lower side wall of the top cap 8 has a drainage pipe 24 connected to the side of the top hat cavity 81. The drainage pipe 24 passes through the pipe B31. It is connected with the liquid measuring pipe 14, and a water stop clamp 29 is installed on the pipe B31. The top of the top cap 8 is provided with an exhaust pipe connected to the top of the top cap cavity 81. The top of the top cap 8 is provided with an exhaust pipe 15 connected with the exhaust pipe. The exhaust pipe 15 is provided with an exhaust valve.

The present invention also includes a computer data processing system 33. The pressure sensor A4 and the pressure sensor B19 are respectively electrically connected to the computer data processing system 33.

As shown in Figure 2, the bottom of the piston 18 is provided with a drainage pressure groove 28 connected to all vertical channels 27. The bottom of the piston 18 is placed with a porous plate 12 located below the drainage pressure groove 28. Between the porous plate 12 and the bottom of the piston 18 Filter paper is also placed.

As shown in Figure 1, a drain pipe connected to the exhaust pipe is provided on the top outer wall of the top cap 8, and a drain valve 5 is installed on the drain pipe. A carrying head 9 is provided on the top plane of the top cap 8 .

The height of the top plane of the preferred permeable stone 25 of the present invention is higher than the height of the water flow channel B21, and at the same time, the height of the top plane of the permeable stone 25 is higher than the height of the water flow channel C22.

Three bolts 17 at 120° to each other are connected between the upper ring 6 and the base 1 to compress and fix the middle ring 10. A circular groove A is provided in the center of the top of the base 1. The bottom of the middle ring 10 fits into the ring of the base 1. In the groove A, an ○-shaped sealing ring B26 is installed between the bottom of the middle ring 10 and the top of the base 1. The bottom of the upper ring 6 is provided with an annular groove B. The top of the middle ring 10 is inserted into the annular groove B of the upper ring 6. An ○-shaped sealing ring C32 is installed between the top of the middle ring 10 and the bottom of the upper ring 6. .

The bottom of the top cap 8 is provided with an annular groove C. The top of the piston 18 is inserted into the annular groove C of the top cap 8. An ○-shaped sealing ring A7 is also installed between the top of the piston 18 and the bottom of the top cap 8. , several ○-shaped sealing rings A7 are installed on the lower outer wall of the piston 18 (when in use, there is a gap ≤0.5mm between the piston 18 and the inner wall of the upper ring 6, and passes between the piston 18 and the inner wall of the upper ring 6 ○ type sealing ring A7 is used for sealing and water proofing). The top surface of the top cap cavity 81 of the top cap 8 forms an angle of 15° with the horizontal plane.

A test method for consolidation test and permeability test of gas-containing soil samples, including a test device, and the method steps are as follows:

A. Install the test device: Place the base 1 on the leveling consolidator and adjust the base 1 to a horizontal position. Install the middle ring 10 on the top of the base 1 that has been coated with Vaseline. Before installing the middle ring 10, install the middle ring 10 on the base 1. An ○-shaped sealing ring B26 is placed between the top and the bottom of the middle ring 10 for sealing. Place the rubber water bladder 2 in the lower water bladder placement cavity in the middle ring 10 so that the pipe head of the rubber water bladder 2 is in airtight communication with the water flow channel A30. Install a pressure sensor B19 on the outlet pipe of the three-way valve A3 to allow the pressure The sensor B19 is connected to the computer data processing system 33, and then the water inlet valve of the three-way valve A3 is opened. Turn the base 1 together with the middle ring 10 sideways so that the water flow channel A30 faces upwards. Use a medical syringe to slowly inject degassed water into the rubber water bag 2 through the water inlet at the three-way valve A3 to discharge the air in the rubber water bag 2. , when the rubber water bladder 2 is completely filled with water, close the water inlet valve of the three-way valve A3; then reset the base 1 together with the middle ring 10, and keep the outlet pipe at the three-way valve A3 connected to the pressure sensor B19. Connect pipe A20 to the water flow channel C22 of the middle ring 10 in a sealed manner, install the three-way valve B23 on the pipe A20, and connect the water supply device 16 and the flow measuring pipe 13 to the other two interfaces of the three-way valve B23 through the pipes. The pressure sensor A4 is hermetically connected to the water flow channel B21 of the middle ring 10, so that the pressure sensor A4 is connected to the computer data processing system 33. Seat the upper ring 6 on the top of the middle ring 10. Place an ○-shaped sealing ring C32 between the upper ring 6 and the middle ring 10. Use three bolts 17 that are 120° to each other to connect and fix the upper ring 6 and the base 1. Tighten all Bolt 17 to compress the middle ring 10. Then put the moist and water-saturated permeable stone 25 and soaked filter paper in sequence on the top of the rubber water bag 2 in the middle ring 10, and put the prepared air-containing soil sample 11 into the upper soil sample cavity of the upper part of the rubber water bag 2, Let it stand for at least 36 hours. After the self-weight consolidation and settlement of the air-containing soil sample 11 is completed, suck out the water precipitated on the surface of the air-containing soil sample 11, place the porous plate 12 on the air-containing soil sample 11, and then put a layer of infiltrated filter paper. Lift and slide the piston 18 in the upper ring 6. Place several ○-shaped sealing rings A7 on the contact surface between the outer wall of the piston 18 and the inner wall of the upper ring 6 for sealing, and make the lower surface of the piston 18 contact the porous plate 12. At the same time, Apply an appropriate amount of Vaseline to the outer wall of piston 18. Cover the top cap 8, connect the drainage pipe 24 on the side of the top cap 8 with the liquid measuring pipe 14 through the pipe B31, open the exhaust valve of the exhaust pipe 15 and loosen the water stop clamp 29 on the pipe B31, and measure the liquid. Inject degassed water into the pipe 14 until the water overflows from the exhaust pipe 15 of the top cap 8, then stop water injection and close the exhaust valve of the exhaust pipe 15. The test device that has been installed with the air-containing soil sample 11 is placed at the predetermined position of the pressurizing platform. The predetermined position of the pressurizing platform is equipped with a pressurizing device and a dial indicator. The pressurizing device has a pressurizing rod. Place the pressurizing device on the predetermined position. The bottom end of the pressure rod is in contact with the load-bearing head 9 at the top of the top cap 8, and the dial indicator is adjusted so that the dial indicator is placed exactly at the center of the top of the pressure rod.

B. Before formal loading, apply a pre-pressure load through the pressurizing device so that the pressure exerted on the gas-containing soil sample 11 displayed by the pressure sensor B19 is 1kPa. After stabilization, reset the dial indicator to zero and measure the gas content at this time. The height H of the air-soil sample 11 is calculated, and the void ratio e ₀ is calculated, which is the initial void ratio before the test, and the reading of the measuring pipe 14 at this time is recorded as V ₁ .

C. Apply an external load through the pressurizing device so that the pressure exerted on the aerated soil sample 11 displayed by the pressure sensor B19 is 2kPa. Record the readings of the dial indicator at each time node and observe the aerated soil sample through the pressure sensor A4. For the dissipation of pore pressure in 11, keep the consolidation pressure of 2kPa unchanged until the pore pressure in air-containing soil sample 11 dissipates to zero.

D. When the pore pressure dissipates to zero, the deformation amount h _i1 of the air-containing soil sample 11 is obtained based on the dial indicator reading. Then the height of the air-containing soil sample after consolidation under this level of load is _Hi1 = Hh _i1 . This level of load is the 2kPa consolidation pressure of step C, passed Obtain the void ratio of the air-containing soil sample 11 at this time, and at the same time read the reading V ₂ of the liquid measuring tube 14 at this time, and there is V _w + V _g = V ₂ - V ₁ , where V _w is the air content of this level of load. The volume of water discharged from soil sample 11, V _g is the volume of gas discharged from air-containing soil sample 11 of this level of load. Open the exhaust valve of the exhaust pipe 15 on the upper part of the top cap 8. After the gas accumulated at the top of the top cap cavity 81 of the top cap 8 is completely eliminated, close the exhaust valve of the exhaust pipe 15 and record the contents of the liquid measuring pipe 14 at this time. The volume reading before and after exhaustion is △V, that is, △V= _Vg . In this level of load consolidation test, the volume of exhaust gas from air-containing soil sample 11 is _Vg . This level of load consolidation test The test is a test under the 2kPa consolidation pressure of step C. Correspondingly, the volume of water discharged from the air-containing soil sample 11 in this level of load consolidation test is V _w =V ₂ -V ₁ -ΔV.

E. Permeability test: After the consolidation test is completed, the permeability test of the air-containing soil sample 11 can be carried out. Use the water stop clamp 29 to cut off the drainage pipe 24 to drain water outwards, and open the drainage valve 5 on the top drainage pipe of the top cap 8. Water allowed to enter the top cap cavity 81 inside the top cap 8 can be drained freely. Adjust the three-way valve B23 and inject degassed water into the flow tube 13 through the water supply device 16 so that the water head height in the flow tube 13 is 1 m. Stop water supply after the water head in the tube stabilizes. Adjust the three-way valve B23 to allow the water in the flow tube 13 to slowly penetrate into and pass through the aerated soil sample 11. When water is discharged from the drain pipe at the top of the top cap 8, start recording the initial water head height h ₁ in the flow tube 13. and the corresponding time t ₁ , record the water head height h ₂ and the corresponding time t ₂ in the flow tube 13 again after a period of time, until the final water head height in the flow tube 13 remains unchanged, record the flow measurement at that moment The water head height h in the pipe 13 and the corresponding time t. Repeat the above operation of the permeability test M times. During each permeability test, the water head height in the flow measuring tube 13 needs to be changed. Finally, the air-containing soil sample 11 at this time can be calculated according to the saturated soil change water head permeability test method in the conventional geotechnical test. permeability coefficient.

F. Continue to apply external load through the pressurizing device, repeat the above steps C to E, and obtain the gas-containing soil sample 11 under various levels of consolidation pressure (consolidation pressure at various levels includes 4kPa, 8kPa, 16kPa, 32kPa ...etc., that is, applying an external load through a pressurizing device, so that the pressure exerted on the aerated soil sample 11 displayed by the pressure sensor B19 is 4kPa, 8kPa, 16kPa, 32kPa...etc.). The consolidation test and penetration test result data, that is The compression coefficient, permeability coefficient and void ratio of the gas-containing soil sample 11 under various levels of consolidation pressure were obtained, and then the consolidation and permeability characteristics of the gas-containing soil sample 11 were evaluated.

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

Claims (10)

1. A test device for the consolidation test and permeability test of gas-containing soil samples, which is characterized by: including a base (1), a middle ring (10), an upper ring (6), a piston (18), and a top cap (8) ), a liquid measuring tube (14), a flow measuring tube (13) and a water supply device (16). The top of the base (1) is tightly connected with a middle ring (10), and the top of the middle ring (10) is sealed with an upper ring (10). 6). The internal cavity of the middle ring (10) includes an upper soil sample cavity and a lower water bladder placement cavity. A rubber water bladder (2) is placed in the lower water bladder placement cavity. The rubber water bladder (2) has a structure similar to that of the water bladder. There is a pipe head connected to the inner cavity. The lower part of the middle ring (10) has a water flow channel A (30) connected to the pipe head of the rubber water bladder (2). The middle ring (10) is equipped with a water flow channel A (30) on the outside. (30) A tightly connected water injection pipe. The water injection pipe is connected with a three-way valve A (3). The three-way valve A (3) is also connected with a water inlet pipe and a water outlet pipe. A pressure sensor B (3) is installed on the water outlet pipe. 19); The middle part of the middle ring (10) has a water flow channel B (21) and a water flow channel C (22) that are higher than the rubber water bladder (2), and a pressure sensor is tightly connected to the water flow channel B (21). A (4), the water flow channel C (22) is connected to a three-way valve B (23) through the pipeline A (20), and the three-way valve B (23) is also connected to the flow measuring tube (13) and the water supply through the pipeline respectively. The device (16) is connected; a permeable stone (25) is placed on the top of the rubber water bladder (2) in the internal cavity of the middle ring (10), and a piston (18) is installed in the internal cavity of the upper ring (6). ), the piston (18) has a number of vertical channels (27) running through it. A top cap (8) is installed on the top of the piston (18), and the top cap (8) has an internal structure connected to the vertical channels (27). ) is connected to the top hat cavity (81). The lower side wall of the top cap (8) is provided with a drainage pipe (24) connected to the side of the top hat cavity (81). The drainage pipe (24) passes through the pipe B (31) It is connected to the liquid measuring pipe (14), and a water stop clamp (29) is installed on the pipe B (31); the top of the top cap (8) has an exhaust pipe connected to the top of the top cap cavity (81), so The top of the top cap (8) is provided with an exhaust pipe (15) connected with the exhaust pipe, and the exhaust pipe (15) is provided with an exhaust valve. 2. A test device for consolidation test and permeability test of gas-containing soil samples according to claim 1, characterized in that: it also includes a computer data processing system (33), and the pressure sensor A (4) and The pressure sensors B (19) are electrically connected to the computer data processing system (33) respectively. 3. A test device for consolidation test and permeability test of gas-containing soil samples according to claim 1 or 2, characterized in that: the bottom of the piston (18) is provided with all vertical channels (27) There is a connected drainage pressure groove (28), and a porous plate (12) located below the drainage pressure groove (28) is placed at the bottom of the piston (18). There is also a gap between the porous plate (12) and the bottom of the piston (18). Place filter paper. 4. A test device for consolidation test and permeability test of gas-containing soil samples according to claim 1 or 2, characterized in that: the top outer wall of the top cap (8) is provided with an exhaust pipe There are connected drainage pipes, and a drainage valve (5) is installed on the drainage pipe. 5. A test device for consolidation test and permeability test of gas-containing soil samples according to claim 1 or 2, characterized in that: a load-bearing head (9) is provided on the top plane of the top cap (8) . 6. A test device for gas-containing soil sample consolidation test and permeability test according to claim 1 or 2, characterized in that: the top plane height of the permeable stone (25) is higher than the water flow channel B ( 21), and at the same time, the height of the top plane of the permeable stone (25) is higher than the height of the water flow channel C (22). 7. A test device for consolidation test and permeability test of gas-containing soil samples according to claim 1 or 2, characterized in that: there are three connections between the upper ring (6) and the base (1). Bolts (17) at 120° to each other are used to compress and fix the middle ring (10). There is a circular groove A in the center of the top of the base (1), and the bottom of the middle ring (10) is plugged into the base (1). In the annular groove A, an ○-shaped sealing ring B (26) is installed between the bottom of the middle ring (10) and the top of the base (1); the bottom of the upper ring (6) is provided with an annular groove B , the top of the middle ring (10) is inserted into the annular groove B of the upper ring (6), and an ○-shaped sealing ring C is installed between the top of the middle ring (10) and the bottom of the upper ring (6). (32). 8. A test device for consolidation test and permeability test of gas-containing soil samples according to claim 4, characterized in that: the bottom of the top cap (8) is provided with an annular groove C, and the The top of the piston (18) is inserted into the annular groove C of the top cap (8), and an ○-shaped sealing ring A (7) is installed between the top of the piston (18) and the bottom of the top cap (8). , several ○-shaped sealing rings A (7) are mounted on the lower outer wall of the piston (18); the top surface of the top cap cavity (81) of the top cap (8) forms an angle of 15° with the horizontal plane. 9. A test method for the consolidation test and permeability test of gas-containing soil samples, which is characterized in that it includes a test device, and the method steps are as follows: A. Install the test device: Place the base (1) on the leveling consolidator and adjust the base (1) to a horizontal position. Install the middle ring (10) on the top of the base (1) that has been coated with Vaseline. Before installing the middle ring (10), place an ○-shaped sealing ring B (26) between the top of the base (1) and the bottom of the middle ring (10) to seal; place the rubber water bladder (2) in the lower water bladder inside the middle ring (10) Place it in the cavity so that the pipe head of the rubber water bladder (2) is tightly connected with the water flow channel A (30). Install the pressure sensor B (19) on the outlet pipe of the three-way valve A (3), and let the pressure sensor B ( 19) Connect to the computer data processing system (33), then open the water inlet valve of the three-way valve A (3), turn the base (1) together with the middle ring (10) sideways, so that the water flow channel A (30) faces upwards , use a medical syringe to slowly inject degassed water into the rubber water bladder (2) through the water inlet at the three-way valve A (3), and discharge the air in the rubber water bladder (2). When the rubber water bladder (2) is filled with When the water is completely filled, close the water inlet valve of the three-way valve A (3); then reset the base (1) together with the middle ring (10), and keep the water outlet pipe at the three-way valve A (3) and the pressure sensor B (19) ) is in a connected state; connect pipeline A (20) to the water flow channel C (22) of the middle ring (10) in a sealed manner, install the three-way valve B (23) on the pipeline A (20), and connect the water supply device (16) , the flow measuring pipe (13) are connected to the other two interfaces of the three-way valve B (23) through pipes respectively; the pressure sensor A (4) is tightly connected to the water flow channel B (21) of the middle ring (10) to allow the pressure Sensor A (4) is connected to the computer data processing system (33); seal the upper ring (6) on the top of the middle ring (10), and place an ○-shaped sealing ring C between the upper ring (6) and the middle ring (10). (32) To seal, use three bolts (17) that are 120° to each other to connect and fix the upper ring (6) and the base (1). Tighten all bolts (17) to compress the middle ring (10); then tighten the middle ring (10) Place the moist and water-saturated permeable stone (25) and soaked filter paper on the top of the rubber water bag (2) in sequence, and put the prepared air-containing soil sample (11) into the upper soil of the rubber water bag (2). In the sample cavity, let it stand for at least 36 hours. After the air-containing soil sample (11) has consolidated and settled under its own weight, suck away the water precipitated on the surface of the air-containing soil sample (11) and place it on the air-containing soil sample (11). Place the porous plate (12) on the surface, and then put a layer of soaked filter paper; lift and slide the piston (18) in the upper ring (6), and place the contact surface between the outer wall of the piston (18) and the inner wall of the upper ring (6) Seal several ○-shaped sealing rings A (7) and make the lower surface of the piston (18) contact the porous plate (12). At the same time, apply an appropriate amount of Vaseline on the outer wall of the piston (18); cover the top cap (8) , connect the drainage pipe (24) on the side of the top cap (8) with the measuring pipe (14) through pipe B (31), open the exhaust valve of the exhaust pipe (15) and loosen pipe B (31) With the water stop clamp (29) on the top cap (8), inject degassed water into the liquid pipe (14) until the water overflows from the exhaust pipe (15) of the top cap (8), then stop water injection and close the exhaust pipe (15) The exhaust valve; place the test device that has been installed with the air-containing soil sample (11) on the predetermined position of the pressurizing platform. The predetermined position of the pressurizing platform is equipped with a pressurizing device and a dial indicator. The pressurizing device has a pressurizing rod. , contact the bottom end of the pressure rod of the pressure device with the load-bearing head (9) at the top of the top cap (8), and adjust the dial indicator so that the dial indicator is exactly placed at the top center of the pressure rod; B. Before formal loading, apply a pre-pressure load through the pressurizing device so that the pressure exerted on the aerated soil sample (11) displayed by the pressure sensor B (19) is 1kPa. After stabilization, reset the dial indicator to zero. Measure the height H of the air-containing soil sample (11) at this time, calculate the void ratio e ₀ , which is the initial void ratio before the test, and note that the reading of the measuring pipe (14) at this time is V ₁ ; C. Apply an external load through the pressurizing device so that the pressure exerted on the aerated soil sample (11) displayed by pressure sensor B (19) is 2kPa. Record the readings of the dial indicator at each time node, and at the same time, through the pressure sensor A (4) Observe the dissipation of pore pressure in the air-containing soil sample (11), and keep the consolidation pressure of 2kPa unchanged until the pore pressure in the air-containing soil sample (11) dissipates to zero; D. When the pore pressure dissipates to zero, the deformation amount h _i1 of the air-containing soil sample (11) is obtained based on the dial indicator reading. Then the height of the air-containing soil sample (11) after consolidation under this level of load is H _i1 = Hh _i1 , the load at this level is the 2kPa consolidation pressure of step C, passed Obtain the void ratio of the air-containing soil sample (11) at this time, and at the same time read the reading V ₂ of the liquid measuring tube (14) at this time, there is V _w + V _g = V ₂ - V ₁ , where V _w is this level The volume of water discharged from the air-containing soil sample (11) under load, V _g is the volume of gas discharged from the air-containing soil sample (11) under load at this level; open the exhaust pipe (15) on the top of the top cap (8) Exhaust valve. After the gas accumulated at the top of the top cap cavity (81) of the top cap (8) is completely eliminated, close the exhaust valve of the exhaust pipe (15) and record the volume reading in the measuring pipe (14) at this time. , the change before and after exhaustion is △V, that is, △V=V _g . In this level of load consolidation test, the volume of exhaust gas from the air-containing soil sample (11) is V _g . In this level of load consolidation test, This is the test under the 2kPa consolidation pressure in step C. The corresponding volume of water discharged from the air-containing soil sample (11) in this level of load consolidation test is V _w =V ₂ -V ₁ -ΔV. 10. A test method for gas-containing soil sample consolidation test and permeability test according to claim 9, characterized in that: after step D, it also includes the following steps E and step F: E. Penetration test: After the consolidation test is completed, the permeability test of the air-containing soil sample (11) can be carried out. Use the water stop clamp (29) to cut off the drainage pipe (24) to drain water outwards, and open the top of the top cap (8) The drain valve (5) on the drain pipe allows the water entering the top cap cavity (81) inside the top cap (8) to be discharged freely; adjust the three-way valve B (23) and pass the water supply device (16) to the flow measuring pipe. (13) Inject degassed water inside to make the water head height in the flow tube (13) be 1m. Stop water supply after the water head in the tube stabilizes; adjust the three-way valve B (23) to make the water in the flow tube (13) slow down. Slowly penetrate into and pass through the air-containing soil sample (11). When water is discharged from the drainage pipe at the top of the top cap (8), start to measure the initial water head height h ₁ and the corresponding time t ₁ in the flow tube (13). After a period of time, record the water head height h ₂ in the flow tube (13) and the corresponding time t ₂ again. When the water head height in the flow tube (13) finally remains unchanged, record the water head height h 2 in the flow tube (13) at that moment. The water head height h and corresponding time t in The test method is used to calculate the permeability coefficient of the gas-containing soil sample (11) at this time; F. Continue to apply external load through the pressurizing device, repeat the above steps C to E, and obtain the consolidation test and permeability test result data of the gas-containing soil sample (11) under various levels of consolidation pressure.