CN108318401A - One kind being suitable for anisotropy permeability coefficient test device under soil solidifying stress - Google Patents

Abstract

The invention discloses an anisotropic permeability coefficient testing device suitable for soil consolidation stress, which includes a pressurization system, an infiltration device and a data acquisition system; wherein the pressurization system is used to pressurize the infiltration device; the data acquisition system It is used to collect the data information when the penetration device conducts the penetration test. The present invention can directly measure the one-dimensional consolidation creep and compression characteristics of soil samples, and can also measure the vertical and horizontal permeability coefficients of soil samples under different consolidation pressures or different deformation conditions, and obtain the initial and one-dimensional deformation-induced Anisotropic characteristics of soil permeability coefficient; this device can apply corresponding consolidation pressure according to different soil depths, which can simulate the actual situation on site very well. The vertical load is applied by a pneumatic device, and the consolidation pressure is obtained by applying gas pressure. According to the linear relationship with the consolidation pressure of the soil sample, the required gas pressure can be obtained according to the purpose of the test to control the consolidation pressure that the soil sample should be subjected to during the test.

Description

An anisotropic permeability coefficient testing device suitable for soil consolidation stress

technical field

The invention relates to an anisotropic permeability coefficient testing device suitable for soil consolidation stress, which belongs to the field of geotechnical engineering test research.

Background technique

The permeability coefficient is an important parameter reflecting the mechanical properties of the soil, which is closely related to the consolidation deformation of the soil and the seepage of groundwater. With the rapid development of urbanization in our country, underground engineering is in full swing, and there are more and more engineering hidden dangers, many of which are closely related to the seepage of water in the soil, such as the treatment of groundwater in deep foundation pit excavation , water interception and drainage should be designed according to the permeability characteristics of the soil; when building earth-rock dams and slopes, the settlement and permeability of the filler should be considered. Because the deep underground strata are affected by the gravity load of the upper layer, the degree of consolidation of the soil in different strata is different, and the permeability of the soil in different strata is also different. At the same time, the permeability properties of the soil under the action of the upper gravity load show obvious anisotropy, that is, the permeability properties of the soil are different in all directions. How to obtain the permeability coefficient of soil at different angles under the consolidation stress through experiments, and conduct in-depth research on the correlation between the anisotropy of its permeability characteristics and engineering characteristics has important scientific and practical significance.

The traditional indoor test methods for measuring permeability coefficient mainly include constant head and variable head permeability test methods, and the permeability coefficient is calculated based on Darcy's law. Both the constant head and variable head penetration tests are completed without axial loading, and are only applicable to surface soil samples. The measured permeability coefficient does not match the actual situation when it is used to test deep soil. Then, many scholars have improved conventional permeameters or developed new permeameters for this specific problem. It is modified, and the pressurized component is used to apply axial pressure to the sample, so that the soil has a certain compression deformation, and a higher water head is applied to the sample seepage liquid. This type of instrument is mainly used to study the vertical seepage of soil under the action of vertical load, and cannot realize the research on the characteristics of horizontal seepage. Therefore, it is necessary to develop a multi-functional joint measurement test device, which can realize the simulation of the specific degree of consolidation of the soil, and can also measure the vertical and horizontal permeability coefficients of the second consolidation stage. Underground engineering seepage stability analysis.

Contents of the invention

The invention provides an anisotropic permeability coefficient testing device suitable for soil consolidation stress to solve the problem that the prior art permeameter cannot be used to realize the research on the anisotropy of the permeability characteristics of the soil under the load state .

The technical solution of the present invention is: an anisotropic permeability coefficient testing device suitable for soil consolidation stress, including a pressurization system, an infiltration device and a data acquisition system; wherein the pressurization system is used to pressurize the infiltration device; The data acquisition system is used to collect data information when the infiltration device conducts the infiltration test.

The pressurization system includes a pneumatic device 3 and a hydraulic device 4; wherein the pneumatic device 3 is connected to the air intake pipe 9 on the cover plate 19 of the permeation device, and the hydraulic device 4 is connected to the base 16 and the sleeve 20 of the permeation device. The water supply pipe 10 is connected.

The permeation device includes a sample chamber 1 and a gas chamber 2; wherein the sample chamber 1 and the gas chamber 2 are surrounded by sleeve 20 side walls, and the bottom of the sample chamber 1 is a base 16, vertically and horizontally inside the sample chamber 1 Grooves are provided in one direction, a permeable stone 21 is placed on the groove in one direction, and a cushion block 22 is placed in the groove in the other direction. The gas chamber 2 is arranged in the middle above the sample chamber 1 and separated by a top plate 18. The top of the gas chamber 2 is Cover plate 19, the intake pipe 9 and the exhaust pipe 12 are arranged on the cover plate 19, the rubber membrane 23 is arranged inside the gas chamber 2 to prevent the water seepage of the sample chamber 1, and the shaft rod 25 is arranged in the middle of the cover plate 19 to pass through the cover plate 19 vertically Finally, it is connected to the top plate 18 through the connecting plate 24; the vertical infiltration water inlet 11 is set in the middle of the base 16, and the base 16 is provided with several communication grooves 17, and the vertical water supply pipe 10 is connected from the side of the base 16 to the middle of the base 16 and connected vertically The infiltration water inlet 11 and the horizontal infiltration water inlet 11 are arranged on the top of the side wall of the sleeve 20, and the horizontal water supply pipe 10 is connected from the top of the side wall of the sleeve 20 to the horizontal infiltration water inlet 11, and the infiltration water passes through the horizontal direction. The infiltration water inlet 11 enters the sample chamber 1; the vertical infiltration water outlet 13 is set in the middle of the top plate 18, and extends to the outside of the device along the shaft 25 through the drain pipe 14 connected to the vertical infiltration water outlet 13, and the horizontal infiltration water outlet 13 is arranged at the bottom of the other side wall of the sleeve 20, and extends to the outside of the device through the drain pipe 14 connected to the horizontal infiltration water outlet 13; the air inlet pipe 9, the water supply pipe 10, the exhaust pipe 12, and the drain pipe 14 are provided with valves 8.

The bottom of the sleeve 20 is connected and fixed on the base 16 by bolts 29, the top of the sleeve 20 is connected and fixed on the cover plate 19 by bolts 29, and the sealing connection between the base 16 and the sleeve 20, and the cover plate 19 and the sleeve 20 is ringed around. Set the rubber ring 28.

The connection between the shaft rod 25 and the cover plate 19 is connected with a seal 26 to ensure tightness.

Described data acquisition system comprises dial indicator 30, air pressure sensor 31, seepage water pressure sensor 32, communication wire 34; Wherein vertically to seepage water pressure sensor 32 is arranged on the base 16 of osmosis device and top board 18 middle, communication line 34 is from The side of the base 16 is connected to the middle of the base 16 and from the inside of the shaft 25 of the osmotic device to the middle of the top plate 18. One end of the communication line 34 is connected to the water pressure sensor 32, and the other end is connected to the computer; the horizontal osmotic water pressure sensor 32 is arranged in the sleeve The water inlet 11 at the top of one side wall of the cylinder 20 and the water outlet 13 at the bottom of the other side wall of the sleeve 20; the dial indicator 30 is arranged on the shaft 25, which is closely connected with the top plate 18, and the solidification stress The bottom moves vertically with the top plate 18; the air pressure sensor 31 is arranged at the bottom of the cover plate 19 in the permeation device, and is extended to the outside of the device through the communication line 34 to transmit the data during the test to the computer.

The dial indicator 30 is fixed on the shaft rod 25 through the fastener 27, and the measuring head is in contact with the sealing member 26 located at the joint between the shaft rod 25 and the cover plate 19 to ensure tightness.

The beneficial effects of the present invention are:

1) The test device for measuring the anisotropic permeability coefficient of soil under vertical load conditions is compatible with one-dimensional consolidation, seepage and seepage pressure, and can directly measure the one-dimensional consolidation creep and compression characteristics of soil samples , at the same time, it can also measure the vertical and horizontal permeability coefficients of soil samples under different consolidation pressures or different deformation conditions, and obtain the anisotropic characteristics of soil permeability coefficients caused by initial and one-dimensional deformation;

2) This device can apply the corresponding consolidation pressure according to the different depths of the soil, which can simulate the actual situation on site very well. The vertical load is applied by the air pressure device. According to the purpose of the test, the required gas pressure is obtained to control the consolidation pressure that the soil sample should be subjected to during the test;

3) The air pressure sensor and water pressure sensor in the data acquisition system are connected to the computer through a communication line, and its electronic digitization and automation technology is used to collect and process data, and to measure the soil sample permeability coefficient with high accuracy and efficiency.

Description of drawings

Fig. 1 is the structural representation of vertical permeability coefficient testing device under the consolidation stress of the present invention;

Fig. 2 is the structural representation of pressurization system of the present invention;

Fig. 3 is a schematic diagram of a cross-sectional structure along A-A in Fig. 1;

Fig. 4 is the structural representation of the vertical infiltration water inlet of the present invention;

Fig. 5 is the structural schematic diagram of the vertically infiltrated water outlet of the invention;

The labels in the figure are: 1-sample chamber; 2-gas chamber; 3-air pressure device; 4-hydraulic device; 5-intake direction; 6-water inlet direction; 7-water outlet direction; 8-valve; 9-intake pipe; 10-water supply pipe; 11-water inlet; 12-exhaust pipe; 13-water outlet; 14-drainage pipe; 15-water penetration direction; 16-base; 17-connecting groove; 18-top ;19-cover plate; 20-sleeve; 21-permeable stone; 22-pad; 23-rubber mold; 24-connecting plate; 25-shaft; 26-seal; 27-fastener; Circle; 29-bolt; 30-dial indicator; 31-air pressure sensor; 32-water pressure sensor; 33-inlet and outlet water hole; 34-communication line.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the content of the present invention is not limited to the stated scope.

Embodiment 1: as shown in Fig. 1-Fig. 5, a kind of anisotropic permeability coefficient testing device applicable to soil consolidation stress, comprises pressurization system, penetration device and data acquisition system; Wherein pressurization system is used for The permeation device is pressurized; the data acquisition system is used to collect data information when the permeation device conducts a permeation test.

Further, the pressurization system can be set to include a pneumatic device 3 and a hydraulic device 4; wherein the pneumatic device 3 is connected to the air intake pipe 9 on the cover plate 19 of the permeation device, and the hydraulic device 4 is connected to the base 16 of the permeation device It is connected with the water supply pipe 10 on the sleeve 20.

Further, the permeation device can be set to include a sample chamber 1 and a gas chamber 2; wherein the sample chamber 1 and the gas chamber 2 are surrounded by sleeve 20 side walls, the bottom of the sample chamber 1 is a base 16, and the sample chamber 1 There are grooves in the vertical and horizontal directions inside, and the permeable stone 21 is placed on the groove in one direction, and the cushion block 22 is placed on the groove in the other direction. The gas chamber 2 is set in the middle above the sample chamber 1 and separated by the top plate 18. The top of the gas chamber 2 is a cover plate 19, on which the air intake pipe 9 and the exhaust pipe 12 are arranged, the inside of the gas chamber 2 is provided with a rubber membrane 23 to prevent water seepage in the sample chamber 1, and the middle position of the cover plate 19 is provided with a shaft 25 vertically After passing through the cover plate 19, it is connected to the top plate 18 through the connecting plate 24; the vertical infiltration water inlet 11 is set in the middle of the base 16, and the base 16 is provided with several communication grooves 17, and the vertical water supply pipe 10 is connected from the side of the base 16 to reach The base 16 is connected to the vertical infiltration water inlet 11 in the middle, the horizontal infiltration water inlet 11 is arranged on the top of the side wall of the sleeve 20, and the horizontal water supply pipe 10 is connected from the top of the side wall of the sleeve 20 to the horizontal infiltration water inlet 11, The infiltration water enters the sample chamber 1 through the horizontal infiltration water inlet 11; the vertical infiltration water outlet 13 is arranged in the middle of the top plate 18, and extends to the outside of the device along the shaft rod 25 through the drain pipe 14 connected to the vertical infiltration water outlet 13. The horizontal infiltration water outlet 13 is arranged at the bottom of the other side wall of the sleeve 20, and extends to the outside of the device through the drain pipe 14 connected to the horizontal infiltration water outlet 13; the air intake pipe 9, the water supply pipe 10, the exhaust pipe 12, the drain pipe 14 is provided with valve 8.

Further, the bottom of the sleeve 20 can be fixed on the base 16 through bolts 29, the top of the sleeve 20 is connected and fixed on the cover plate 19 through bolts 29, the base 16 and the sleeve 20, the cover plate 19 and the sleeve 20 A rubber ring 28 is arranged around the ring of the sealed joint.

Further, a sealing member 26 may be provided at the joint between the shaft rod 25 and the cover plate 19 to ensure tightness.

Further, the data acquisition system can be set to include a dial gauge 30, an air pressure sensor 31, a permeate water pressure sensor 32, and a communication line 34; wherein the vertical permeate water pressure sensor 32 is arranged between the base 16 and the top plate 18 of the permeate device , the communication line 34 is connected from the side of the base 16 to the middle of the base 16 and from the inside of the shaft 25 of the osmosis device to the middle of the top plate 18. One end of the communication line 34 is connected to the water pressure sensor 32, and the other end is connected to the computer; The sensor 32 is set at the water inlet 11 at the top of one side wall of the sleeve 20 and the water outlet 13 at the bottom of the other side wall of the sleeve 20; the dial indicator 30 is set on the shaft 25, which is closely connected with the top plate 18 , moves vertically with the top plate 18 under the consolidation stress; the air pressure sensor 31 is set at the bottom of the cover plate 19 in the permeation device, and extends out of the device through the communication line 34 to transmit the data during the test to the computer.

Further, the dial indicator 30 can be fixed on the shaft 25 through the fastener 27, and the measuring head is in contact with the seal 26 at the joint between the shaft 25 and the cover plate 19 to ensure tightness.

The working principle of the present invention is:

The purpose of the pressurization system is to provide the sample with the consolidation pressure required for the test and to control the water head of the permeating liquid; the pressurization device 3 causes the top plate 18 to move downward in the axial direction by increasing the internal pressure of the gas chamber 2, and the sample The sample inside the chamber 1 is compressed and deformed by the downward stress of the top plate 18; the pressure adding device 3 controls the loading mode of the sample by increasing the amplitude of the gas, which can be divided into staged loading and separate loading according to the purpose of the test; the hydraulic pressure device 3 4 Control the water head by increasing the pressure of the penetrating liquid.

The permeation device system is the core of the whole test device. Its purpose is to prepare, saturate and consolidate the sample. It can directly measure the one-dimensional consolidation creep and compression characteristics of the soil sample. At the same time, it can also measure the water inlet 11 and water outlet 13. The water head and the amount of water passing through the sample are used to calculate the permeability coefficient according to Darcy's law.

The purpose of the data acquisition and processing system is to collect and process the data and results of the entire sample process without recording the entire infiltration process, and to test the permeability coefficient of the soil with high accuracy and efficiency; the vertical infiltration water pressure sensor 32 is set In the middle of the base 16 and the top plate 18, the communication line 34 is inserted from the side of the base 16 and the inside of the shaft rod 25 to reach the middle of the base 16 and the top plate 18. One end of the communication line 34 is connected to the water pressure sensor 32, and the other end is connected to the computer; The water pressure sensor 32 is arranged at the water inlet 11 at the top of the side wall of the sleeve 20 and at the water outlet 13 at the bottom of the side wall of the other symmetrical sleeve; 18 is tightly connected, and moves vertically with the top plate 18 under the consolidation stress, the connection between the shaft 25 and the cover plate 19 is connected with a seal 26 to ensure tightness, and the dial gauge 30 is fixed on the shaft 25 through a fastener 27 Above, the measuring head is in contact with the sealing member 26; the gas pressure sensor 31 is arranged on the inner cover plate 19 of the gas chamber 1, and the communication line 34 extends out of the device to transmit the data during the test to the computer.

Adopt the present invention to test, at first prepare the sample soil according to certain requirements, then select to prepare in the sample room according to the test purpose or put it into the sample room 1 after being prepared outside the sample room; measure the penetration according to the test purpose before loading the sample coefficient, if the vertical penetration test is carried out, the permeable stone 21 is placed on the upper and lower grooves (ie, the horizontal direction), and the impermeable pads 22 are placed in the left and right (ie, vertical) grooves, and Vaseline is applied to the pads 22 to ensure tightness If the water inflow and outflow valves 8 are closed horizontally; if the horizontal penetration test is to be carried out, then place permeable stones 21 in the left and right grooves (ie vertically), and place impermeable pads 22 in the upper and lower grooves (ie horizontally). , the ring spacer 22 smears vaseline, and closes the water inlet and outlet valves 8 vertically.

After the sample loading is completed, the gas pressure in the gas chamber 2 is increased by the pressure adding device 3, and the extrusion top plate 18 moves downward to apply vertical pressure to the sample. If the penetration of the sample in the sample chamber 1 without consolidation pressure is studied characteristics, use the air pressure device 3 to add a little pressure to the gas chamber 2, so that the top plate 18 contacts the soil; if the compression deformation and permeability characteristics of the sample in the sample chamber 1 are studied under a certain consolidation pressure, use the pressurized The device 3 exerts a corresponding vertical pressure.

During the consolidation test, the applied consolidation pressure is obtained indirectly through the analysis and calculation of the linear relationship between the applied gas pressure and the soil sample consolidation pressure. During the one-dimensional consolidation process of the soil, the compression of the soil is measured by the dial gauge 30 At the same time, open the water inlet and water outlet valves 8 of the permeation device to drain the water that seeps out when the soil is compressed. After the compression deformation is stable, close the corresponding valves 8 and connect the corresponding pipelines to conduct the penetration test.

When performing a penetration test, the hydraulic device 4 controls the water head of the penetrating liquid by increasing the pressure of the liquid, and a stable water pressure is provided by the water supply pipe 10, and the water pressure at the water inlet and outlet can be measured by the water pressure sensor 32; 10 Inject the sample chamber 1 through the inlet and outlet holes 33 on the water pressure sensor. When penetrating vertically, the penetrating liquid passes through the base 16 and connects with the groove 17 to infiltrate and distribute evenly in the specimen chamber 1. When penetrating horizontally, the penetrating liquid is under the action of gravity. Gradually fill the entire horizontal seepage surface; the seepage liquid has a certain water head and flows vertically or horizontally in the soil sample, and the seepage flow through the sample can be provided by the water supply pipe 10 and the flow out of the drain pipe 14 within a certain period of time. Confirm the water volume; clean the permeation device after the test.

The water heads of the two cross-sections at the water inlet 11 and the water outlet 13 in the sample are known, the vertical distance and the area of the cross-section are known, and the flow rate is known, so the corresponding permeability coefficient of the soil sample can be calculated.

The specific implementation of the present invention has been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned implementation, within the knowledge of those of ordinary skill in the art, it can also be made without departing from the gist of the present invention. Variations.

Claims (7)

1. one kind being suitable for anisotropy permeability coefficient test device under soil solidifying stress, it is characterised in that：Including compression train System, permeability apparatus and data collecting system；Wherein compression system is for pressurizeing to permeability apparatus；Data collecting system is used for Acquire data information when permeability apparatus carries out permeability test.

2. according to claim 1 be suitable for anisotropy permeability coefficient test device under soil solidifying stress, feature It is：The compression system includes aerating pressure device（3）With liquid feeding pressure device（4）；Wherein aerating pressure device（3）With permeability apparatus Cover board（19）On air inlet pipe（9）Connection, liquid feeding pressure device（4）With the pedestal of permeability apparatus（16）And sleeve（20）On confession Water pipe（10）Connection.

3. according to claim 1 be suitable for anisotropy permeability coefficient test device under soil solidifying stress, feature It is：The permeability apparatus includes sample chamber（1）And gas compartment（2）；Wherein sample chamber（1）And gas compartment（2）Surrounding is sleeve （20）Side wall, sample chamber（1）Bottom is pedestal（16）, in sample chamber（1）Internal vertical is equipped with groove, a direction to horizontal direction Permeable stone is placed on groove（21）, place cushion block on other direction groove（22）, gas compartment（2）It is arranged in sample chamber（1）Top Centre simultaneously passes through top plate（18）It separates, gas compartment（2）Top is cover board（19）, cover board（19）Upper setting air inlet pipe（9）And exhaust Pipe（12）, gas compartment（2）Being internally provided with prevents sample chamber（1）The rubber membrane of infiltration（23）, cover board（19）Centre position is arranged Shaft（25）Pass perpendicularly through cover board（19）After pass through connecting plate（24）It is connected to top plate（18）；Vertically to infiltration water inlet（11）If It sets in pedestal（16）Centre, pedestal（16）If being provided with arterial highway communication groove（17）, vertically to feed pipe（10）From pedestal（16） Side access reaches pedestal（16）Centre connection is vertically to infiltration water inlet（11）, horizontal direction infiltration water inlet（11）Setting is covering Cylinder（20）At the top of one side wall, horizontal direction feed pipe（10）From sleeve（20）Horizontal direction infiltration water inlet is accessed at the top of one side wall （11）, infiltration water is through horizontal direction infiltration water inlet（11）Into sample chamber（1）；Vertically to infiltration water outlet（13）It is arranged in top plate （18）Centre, through with it is vertical to infiltration water outlet（13）The drainpipe of connection（14）Direct-axis bar（25）Outside internal stretch to device, Horizontal direction permeates water outlet（13）It is arranged in sleeve（20）Another sidewall bottom, through permeating water outlet with horizontal direction（13）Connection Drainpipe（14）It extends to outside device；Air inlet pipe（9）, feed pipe（10）, exhaust pipe（12）, drainpipe（14）It is equipped with valve （8）.

4. according to claim 3 be suitable for anisotropy permeability coefficient test device under soil solidifying stress, feature It is：The sleeve（20）Bottom passes through bolt（29）It is fastened on pedestal（16）On, sleeve（20）Top passes through bolt （29）It is fastened on cover board（19）On, pedestal（16）With sleeve（20）, cover board（19）With sleeve（20）Ring one at sealed connection Week setting rubber ring（28）.

5. according to claim 3 be suitable for anisotropy permeability coefficient test device under soil solidifying stress, feature It is：The shaft（25）With cover board（19）Junction is to ensure tightness sealing element（26）It is attached.

6. according to claim 1 be suitable for anisotropy permeability coefficient test device under soil solidifying stress, feature It is：The data collecting system includes dial gauge（30）, air pressure force snesor（31）, infiltration water pressure sensor（32）, it is logical Believe line（34）；Wherein vertically to infiltration water pressure sensor（32）Pedestal in permeability apparatus is set（16）And top plate（18）In Between, communication line（34）From pedestal（16）Side access reaches pedestal（16）Shaft intermediate and from permeability apparatus（25）Inside access Reach top plate（18）Centre, communication line（34）One end connects water pressure sensor（32）, other end connection computer；Horizontal direction is oozed Permeable pressure sensor（32）It is arranged in sleeve（20）Water inlet at the top of one side wall（11）Place and sleeve（20）Another side wall bottom The water outlet in portion（13）Place；Dial gauge（30）It is arranged in shaft（25）On, shaft（25）With top plate（18）Close connection, is consolidating With top plate under stress（18）It is vertically movable；Air pressure force snesor（31）It is arranged in permeability apparatus cover plate（19）Bottom, by logical Believe line（34）It extends to outside device and the data during experiment is transferred to computer.

7. according to claim 6 be suitable for anisotropy permeability coefficient test device under soil solidifying stress, feature It is：The dial gauge（30）Pass through fastener（27）It is fixed on shaft（25）On, measurement head be located at shaft（25）With cover board （19）Junction is the sealing element for ensureing tightness（26）It is contacted.