CN202661326U - Multifunctional unsaturated soil three-axis test device capable of circularly applying suction force - Google Patents
Multifunctional unsaturated soil three-axis test device capable of circularly applying suction force Download PDFInfo
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- CN202661326U CN202661326U CN 201220229007 CN201220229007U CN202661326U CN 202661326 U CN202661326 U CN 202661326U CN 201220229007 CN201220229007 CN 201220229007 CN 201220229007 U CN201220229007 U CN 201220229007U CN 202661326 U CN202661326 U CN 202661326U
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Abstract
The utility model discloses a multifunctional unsaturated soil three-axis test device capable of circularly applying suction force, relating to the field of soil test. The test device is an improvement of the conventional saturated soil three-axis test equipment, is reserved with a confining pressure unit, an axial force application unit and an axial displacement measurement unit, and is provided with a suction application unit, a temperature control unit, a dual-pressure chamber, a differential pressure sensor, a reference tube and a data acquisition unit. The test method comprises the steps of arranging a saturated remolded soil sample or an undisturbed sample in a three-axis pressure chamber, and applying the suction force in the pressure chamber so as to enter an unsaturated stage; and applying confining pressure to perform shear test on the unsaturated soil to obtain deformation curves and strength parameters of the deformation curves under different suction forces and different confining pressures. The multifunctional unsaturated soil three-axis test device is suitable for dehumidification and moisture absorption, solidification, undrained shear and drainage shear tests under different temperatures of unsaturated soil, and the strength test under different hydraulic paths can be realized.
Description
Technical field
The utility model relates to the soil test field, relates in particular to the unsaturated soil Triaxial tester that a kind of multifunctional circulation applies suction.
Background technology
In vast arid and semi-arid lands, major part all is unsaturated soil; And a large amount of geologic hazards is relevant with unsaturated soil.Because experimental technique and the theoretical level of unsaturated soil can not show a candle to the saturated soil maturation, in order to simplify, the present analysis problems normally adopts saturated soil theoretical.Along with the researchist is more and more deep to the understanding of unsaturated soil, adopt the theoretical solution of unsaturated soil problems more reasonable.The essential distinction of unsaturated soil and saturated soil is that saturated soil has the stress history dependence, and unsaturated soil is not only relevant with stress history, and relevant with hydraulics history.Different from saturated soil, unsaturated soil is the three-phase porous medium, comprises solid phase, gas phase and liquid phase.Because the existence of gas phase, the pore water pressure in the unsaturated soil are normally born.
Because unsaturated soil Duo gas phase than saturated soil, more than therefore stress variable, i.e. a suction.Suction is that surface and the interior liquid and gas of hole of inside soil body solid phase interact and generation, and the strength and stiffness of the soil body are increased.Therefore the theory of saturated soil and experimental technique are also inapplicable, have often underestimated the safety coefficient of the soil body.Simultaneously, owing to there being the effect of capillary hysteresis, for same matric suction, pass through respectively dehumidification not identical, also relevant with saturation degree with the intensity of the moisture absorption soil body afterwards, and relevant with drying and watering cycle history.
When analyzing the unsaturated soil disaster problem of rainfall induced landslide and so on, the intensity index of the soil body is one of most important parameter.And these parameters are relevant with suction, so suction is to need the problem that will solve badly to the contribution of intensity.The earth surface cracks that the simultaneously evaporation relevant with unsaturated soil causes and the migration of the pollutant of refuse landfill and temperature have substantial connection, the native water state of unsaturated soil is also relevant with temperature, and there be limited evidence currently of has research to relate to mechanics and the hydraulic properties of unsaturated soil under the test different temperatures.Different native water states can cause different intensive parameters, therefore when this type of unsaturated soil problem of analysis, are necessary to study the impact of temperature.Opposite with unsaturated soil, the measuring accuracy of the indoor triaxial test of saturated soil and controllability have obtained generally acknowledging of domestic and international rock-soil mechanics field.
For the testing equipment of unsaturated soil, researchist both domestic and external has carried out a large amount of research at present.To unsaturation soil suction control technology, major part realizes by axle translation technology.The axle translation be with the hole press be increased on the occasion of, also increase air pressure simultaneously, apply the matric suction of setting by the two difference.But when being generalized to presence states, the hole in the unsaturated soil is pressed and is all born, and this technology is just no longer applicable.No longer need to apply atmospheric pressure, during the negative hole pressure condition of true reappearance soil sample at the scene the time, can apply suction and be a difficult problem in the unsaturated soil research.And existing method is the soil sample bottom discharge, or soil sample top and together draining of bottom, and equilibration time is very long, and degree of accuracy is not high.The test unit of studying simultaneously test unsaturated soil behavior under different temperatures neither be a lot.
Summary of the invention
The purpose of this utility model just is to overcome prior art existent defect and deficiency, the unsaturated soil Triaxial tester that provides a kind of multifunctional circulation to apply suction.
This test unit is simple in structure, and is easy to use, can accurately reflect mechanics and the hydraulic properties of unsaturated soil under the different temperatures.
This test method mainly is to adopt dialysis to reach needed suction, and press close to on-the-spot virtual condition in the negative hole in the soil sample, and carries out test under the different temperatures in conjunction with temperature control unit.Desorption is wet around adopting soil sample, has shortened the time of unsaturated soil balance.
The purpose of this utility model is achieved in that
This test unit is the improvement to existing " saturated soil triaxial test equipment ", keep wherein confined pressure unit, axle power applying unit and axial displacement measuring unit, be provided with suction applying unit, temperature control unit, two pressure chamber, differential pressure pick-up, reference pipe and data acquisition unit.
This test method is: first saturated remoulded sample or undisturbed soil sample are placed the triaxial cell, apply suction in the pressure chamber, make it enter the unsaturation stage; Then apply confined pressure unsaturated soil is carried out shear test, obtain deformation curve and intensive parameter thereof under different suction and the different confined pressures.Suction can circulation change, thereby can obtain the strength characteristic in different waterpower path; Can obtain simultaneously mechanical property and the hydraulic properties of unsaturated soil under the different temperatures by temperature control unit; And wherein the negative hole pressure condition of unsaturated soil near on-the-spot former bit pattern.
One, multifunctional circulation applies the unsaturated soil Triaxial tester (abbreviation test unit) of suction
This test unit comprises confined pressure unit, axle power applying unit and axial displacement measuring unit, is provided with suction applying unit, temperature control unit, two pressure chamber, differential pressure pick-up, reference pipe and data acquisition unit.
Its annexation is:
Suction applying unit, confined pressure unit, axle power applying unit are connected with temperature control unit with two pressure chambers and are connected, and soil sample are applied suction, confined pressure, axle power and the temperature of setting;
Differential pressure pick-up is connected with two pressure chambers with the axial displacement measuring unit and is connected, and differential pressure pick-up connects with the pipe of being connected, and the volume change in the soil sample test process and axial displacement are measured in real time;
Data acquisition unit is connected with temperature control unit with confined pressure unit, axle power applying unit respectively, confined pressure, axle power and temperature value that control applies;
The suction applying unit is connected with data acquisition unit, and the quality difference of record inflow and outflow solution comes to suck or discharge in the inverse soil sample quality of water, judges simultaneously whether corresponding this one-level suction soil sample reaches equilibrium state;
Differential pressure pick-up is connected with data acquisition unit with the axial displacement measuring unit and is connected, and in process of the test volume change and axial displacement is carried out Real-time Collection.
The principle of work of this test unit:
Adopt dialysis to apply required suction, its principle is to utilize the dialysis power of PEG solution.Because the PEG solution of variable concentrations produces the osmotic suction of different sizes to the moisture of the unsaturation soil sample of film opposite side by the barrier effect of semi-permeable diaphragm, and soil sample moisture is in change procedure, only reached balance at the matric suction that moisture is had RETENTION BY SOILS and the osmotic suction of solution, soil sample moisture just can remain unchanged.Therefore adopt the PEG solution dialysis soil sample of variable concentrations also just to reach soil sample is applied purpose with controlled suction.
Apply respectively confined pressure, suction by confined pressure unit and suction applying unit, realize the Real-time Collection of data by data acquisition unit, carry out the desorption wet test under the different confined pressures of unsaturated soil;
Regulate temperature by temperature control unit, carry out hydraulics test and the mechanical test of unsaturated soil under the different temperatures;
Connect two pressure chamber's inner rooms and reference pipe by differential pressure pick-up, when undrained shear, the volume change of soil sample can make the liquid level of the solution in two pressure chambers raise or reduce, reflect the variation of soil sample volume by the pressure reduction with the reference pipe, by with data acquisition unit be connected to come Real-time Collection;
Link to each other with the top of two pressure chambers by shaft position sensor, carry out Real-time Collection by data acquisition unit;
Whole process implementation under different temperatures, suction and the confined pressure condition to the Real Time Monitoring of unsaturation soil sample mechanics and hydraulics behavior, and the difference of testing unsaturated soil intensity under the different hydraulicss path.
Two, multifunctional circulation this test method of unsaturated soil triaxial test method (abbreviation test method) of applying suction is based on the unsaturated soil Triaxial tester that above-mentioned multifunctional circulation applies suction, comprises the following steps:
1. the installation of soil sample
Adopt static pressure method to make three axle soil sample (cylindrical soil samples by the dry density of setting and water percentage soil sample, be called for short soil sample), soil sample is vacuumized saturated, then waterproof base plate is put on pressure chamber's base, soil sample is packed in the semi-permeable diaphragm, compacting is to get rid of the air in the film slightly, be installed in together on pressure chamber's base with waterproof base plate, be placed with waterproof cover plate on the top of soil sample, and then with elastic string the up and down two ends of semi-permeable diaphragm (the up and down two ends of soil sample are longer than at two ends about the semi-permeable diaphragm) tightened respectively on the waterproof base plate and waterproof cover plate on pressure chamber's base;
2. adopt dialysis to apply needed suction
Be filled with certain density PEG solution to two pressure chambers inner room, the corresponding specific suction of each concentration makes solution reach the position a little on the lower, top of inner room, then injects certain lightweight oil in the mistress, make lightweight oil enter inner room, reach the concordant contact of two Room liquid levels;
3. test
The native water characteristic curve of unsaturated soil under a, the test different temperatures;
The native water characteristic curve of unsaturated soil under b, the different confined pressures of test;
C, carry out the consolidation test of unsaturated soil under the different suction;
D, the three axle drainings of carrying out unsaturated soil under different suction and the different confined pressures and undrained shear test;
E, carry out the strength test of unsaturated soil under the different waterpower path.
The utlity model has following advantage and good effect:
1. confined pressure unit, suction applying unit and temperature control unit are controlled, can add in advance the value of setting;
2. desorption wet test, consolidation test, undrained shear test and the draining shear test of unsaturated soil be can carry out respectively same soil sample, and unsaturated soil mechanical property under different temperatures and the simultaneous determination of hydraulic properties realized;
3. can accurately measure and control volume change and axial displacement in suction, confined pressure, temperature and the process of the test of unsaturation soil sample;
4. do not adopt axle translation technology, can reproduce the negative hole pressure condition of unsaturated soil under the presence states;
5. can realize that soil sample circulation desorption is wet, carry out the strength test of unsaturated soil under the different hydraulics history;
6. realize the Real-Time Monitoring of all test figures and automatically collection, do not need artificial reading on duty;
7. this device to test principle is directly perceived, simple in structure, precision is high, good stability, without heavy equipment, easy operating, convenient disassembly and cheap, the installation testing personnel are not had very high technical requirement.
The utility model is applicable to that desorption under the unsaturated soil different temperatures is wet, fixed, undrained shear and draining shear test, and can realize the strength test under the different waterpower path.
Description of drawings
Fig. 1 is the block diagram of this test unit;
Fig. 2 is the structural representation of this test unit;
Fig. 3 is the data acquisition unit block diagram;
Fig. 4 is the workflow diagram of computing machine.
Among the figure:
0-soil sample;
1-suction applying unit,
1.1-semi-permeable diaphragm, the PEG(polyglycol of 1.2-variable concentrations) solution,
1.3-normal flow pump;
2-confined pressure unit,
2.1-pressure controller, the 2.2-lightweight oil, the 2.3-tensimeter,
2.4-confined pressure valve;
3-axle power applying unit,
3.1-lifting table, the 3.2-handwheel,
3.3-axial dynamometer, 3.4-testing machine;
The 4-temperature control unit,
4.1-resistance wire, 4.2-compressor, 4.3-temperature controller;
5-two pressure chambers,
5.1-inner room, 5.2-mistress, 5.3-confined pressure duct,
5.4-suction duct, 5.5-exhaust passage, 5.6-base,
5.7-waterproof base plate, the waterproof cover plate of 5.8-;
The 6-differential pressure pick-up;
7-is with reference to pipe;
8-axial displacement measuring unit,
8.1-the axial displacement dial gauge, 8.2-displacement surveymeter;
9-data acquisition unit,
9.1-confined pressure sensor, 9.2-flow sensor, 9.3-axial force sensor,
9.4-temperature sensor, 9.5-shaft position sensor, 9.6-data collecting instrument,
9.7-computing machine.
Embodiment
Describe in detail below in conjunction with drawings and Examples:
One, test unit
1, overall
Such as Fig. 1, this test unit comprises confined pressure unit 2, axle power applying unit 3 and axial displacement measuring unit 8;
Be provided with suction applying unit 1, temperature control unit 4, two pressure chamber 5, differential pressure pick-up 6, reference pipe 7 and data acquisition unit 9;
Its annexation is:
Differential pressure pick-up 6 is connected with the axial displacement measuring unit and is connected with two pressure chambers 5 respectively, and differential pressure pick-up 6 and the pipe of being connected 7 connect, and volume change and axial displacement in soil sample 0 process of the test are measured in real time;
Data acquisition unit 9 is connected with temperature control unit with confined pressure unit 2, axle power applying unit 3 respectively and is connected confined pressure, axle power and temperature value that control applies;
Differential pressure pick-up 6 is connected with the axial displacement measuring unit and is connected with data acquisition unit 9 respectively, in process of the test volume change and axial displacement is carried out Real-time Collection.
2, functional block
1) the suction applying unit 1
Such as Fig. 2, suction applying unit 1 comprises the PEG(polyglycol of semi-permeable diaphragm 1.1, variable concentrations) solution 1.2 and normal flow pump 1.3;
Its annexation is:
Semi-permeable diaphragm 1.1 parcel soil samples 0, be filled with certain density PEG solution 1.2 to two pressure chambers inner room 5.1, corresponding suction is provided, normal flow pump 1.3 links to each other with inner room 5.1 both sides, two pressure chambers, the circulation of one side provides the PEG solution 1.2 of constant flow rate, opposite side flows out solution and records its mass change, is used for drawing the quality that soil sample 0 absorbs or discharge water;
Normal flow pump 1.3 links to each other with data acquisition unit 9 by signal transmssion line.
The principle of work of suction applying unit 1 is:
Adopt dialysis to apply suction, at a certain temperature, the PEG solution 1.2 of every kind of concentration has the suction value of a correspondence.Semi-permeable diaphragm 1.1 is a kind ofly can only see through micromolecular material, and the effect of semi-permeable diaphragm 1.1 is exactly to separate PEG solution 1.2 and test soil sample 0, and hydrone can pass through, and the PEG molecule of macromolecule can't pass through.Because the suction during original state in the soil sample 0 is different with the suction in pressure chamber's inner room 5.1, in order to reach balance, beginning dehumidification or moisture absorption in the soil sample 0 are until reach balance.When soil sample 0 no longer during water outlet, namely the suction in the soil sample 0 and the suction in the PEG solution 1.2 reach balance, thereby have realized applying of suction.In order to guarantee the dialysis effect, the PEG solution 1.2 in pressure chamber's inner room 5.1 is by the successively supply of normal flow pump 1.3.Semi-permeable diaphragm 1.1 can adopt bag filter, if its specification is MWCO value 3500, the expression molecular weight is higher than 3500 macromolecular compound and can't passes namely and can be held back by this kind bag filter.PEG solution 1.2 is the abbreviation of polyethylene glycol, should adopt PEG6000 solution.During different temperatures, on the rating curve of the concentration of this type PEG solution 1.2 and suction, can check in the suction value of corresponding variable concentrations.Soil sample 0 adopts peripheral draining or suction, reaches the required time of balance short, has greatly saved the time of whole test.
The function of suction applying unit 1 is:
Soil sample 0 is applied the suction of setting, can reproduce the negative hole pressure condition of unsaturated soil under the on-the-spot original position state, carry out the triaxial test of unsaturated soil under the given suction, and measure the quality that soil sample 0 absorbs or discharge water by normal flow pump 1.3, can measure the volume change of triaxial test simultaneously.
2) the confined pressure unit 2
Described confined pressure unit 2(is a functional unit of existing " saturated soil triaxial test equipment ") comprise pressure controller 2.1, lightweight oil 2.2, tensimeter 2.3 and confined pressure valve 2.4;
Its annexation is:
Be full of lightweight oil 2.2 in the mistress of pressure chamber 5.2, pressure controller 2.1, confined pressure valve 2.4 and lightweight oil 2.2 are communicated with successively, are provided with tensimeter 2.3 at pressure controller 2.1.
The principle of work of confined pressure unit 2 is:
2.1 pairs of lightweight oils 2.2 of pressure controller exert pressure to produce the confined pressure of setting, and confined pressure valve 2.4 and tensimeter 2.3 are used for respectively setting and showing the numerical value of confined pressure, and tensimeter 2.3 links to each other with data acquisition unit 9 by signal transmssion line, controls and monitors.
The function of confined pressure unit 2 is:
Soil sample 0 is applied required confined pressure, carry out wet, the fixed and shear test of the desorption of unsaturated soil under the different confined pressures.
3) axle power applying unit 3
Axle power applying unit 3(is a functional unit of existing " saturated soil triaxial test equipment ") comprise lifting table 3.1, handwheel 3.2, axially dynamometer 3.3 and testing machine 3.4;
Its annexation is:
From top to bottom, testing machine 3.4, lifting table 3.1, two pressure chamber 5 and the dynamometer of being connected 3.3 connect successively, apply axle power for soil sample 0;
Be provided with handwheel 3.2 at testing machine 3.4, play the unloading effect.
The principle of work of axle power applying unit 3 is:
It is strain control formula that axle power applies, and rises with certain speed drive lifting table 3.1 by testing machine 3.4, and the axial strain of soil sample 0 is increasing always, and realization applies soil sample 0 axial force, until soil sample 0 is destroyed.The axle power value that obtains applying by axial dynamometer 3.3, and carry out Real-time Collection by being connected with data acquisition unit 9.
The function of axle power applying unit 3 is:
Soil sample 0 is applied axle power, carry out three axle draining shearings and undrained shear test under different confined pressures, temperature and the suction condition.
Lifting table 3.1, handwheel 3.2, axial dynamometer 3.3 and testing machine 3.4 are general part.
4) temperature control unit 4
Its annexation is:
Resistance wire 4.1 is built in the two mistress of pressure chamber 5.2 inwalls, and compressor 4.2 is communicated with two mistress of pressure chamber 5.2 by flexible pipe, and temperature controller 4.3 is connected with compressor with resistance wire 4.1 respectively and is connected, and controls temperature.
The principle of work of temperature control unit 4 is:
Set the temperature that will reach by temperature controller 4.3, if the temperature in the solution heats than the low 4.1 pairs of liquid of built-in resistance wire that then feed back to of setting value, lower the temperature if the temperature in the solution then feeds back to compressor 4.2 than setting value height, and keep temperature constant.
The function of temperature control unit 4 is:
Can set needed temperature, and keep constant temperature.
5) two pressure chambers 5
Two pressure chambers 5 comprise inner room 5.1, mistress 5.2, confined pressure duct 5.3, two suction ducts 5.4, exhaust passage 5.5, base 5.6, waterproof base plate 5.7 and waterproof cover plates 5.8;
Its annexation is:
Inner room 5.1 and mistress 5.2 are installed in respectively on the base 5.6, and the upper end open of inner room 5.1 is communicated with mistress 5.2;
Confined pressure duct 5.3 is arranged on the base 5.6 that is communicated with mistress 5.2, is used for applying confined pressure;
One termination in two suction ducts 5.4 is arranged on the base 5.6 that is communicated with inner room 5.1, another termination in two suction ducts 5.4 is communicated with normal flow pump 1.3, is used for the variation of moisture and the volume change in the triaxial test process in circulation-supplied PEG solution 1.2 and the measurement soil sample 0;
Exhaust passage 5.5 is arranged on the top of two pressure chambers 5, is used for getting rid of indoor air.
The principle of work of two pressure chambers 5 is:
In inner room 5.1, inject PEG solution 1.2, be used for applying the suction of soil sample 0; Inject the confined pressure that lightweight oil 2.2 is used for applying soil sample 0 in mistress 5.2, soil sample 0 is placed on the inner room base 5.6; In two pressure chambers 5, inner room 5.1 and mistress's 5.2 pressure equates, has offset the distortion of inner room 5.1, thereby more can accurately measure soil sample 0(unsaturated soil) volume change; Top at inner room 5.1 is provided with scale mark, is used for the maximum height that solution is injected in control.
The function of two pressure chambers 5 is:
Place soil sample 0, realization soil sample 0 is and shear test wet, fixed with the desorption under the different confined pressures in different temperatures.
6) differential pressure pick-up 6
Differential pressure pick-up 6 is a kind of general parts.
One end links to each other with inner room 5.1, and the other end links to each other with reference pipe 7.At soil sample 0(unsaturated soil) undrained shear the time, because soil sample 0 volume change can make the liquid level of the PEG solution 1.2 in the inner room 5.1 change, with can produce corresponding variation with reference to the pressure differential of pipe in 7, by this pressure differential soil sample 0(unsaturated soil in the test that can convert) volume change.By linking to each other with data acquisition unit 9, can become by the Real-Time Monitoring body simultaneously.
7) with reference to pipe 7
8) the axial displacement measuring unit 8
Axial displacement measuring unit 8(is a functional unit of existing " saturated soil triaxial test equipment ") comprise axial displacement dial gauge 8.1 and displacement surveymeter 8.2;
Its annexation is:
Offset table 8.1 links to each other with data acquisition unit 9 by signal transmssion line, and displacement surveymeter 8.2 contacts with 5 tops, two pressure chamber.
The function of axial displacement measuring unit 8 is:
The axial displacement that can Real-Time Monitoring unsaturated soil desorption occurs in wet, the fixed and shear test process.
9) data acquisition unit 9
As shown in Figure 3, data acquisition unit 9 comprises confined pressure sensor 9.1, flow sensor 9.2, axial force sensor 9.3, temperature sensor 9.4, shaft position sensor 9.5, data collecting instrument 9.6 and computing machine 9.7;
Its annexation is:
Have six passages to be connected with differential pressure pick-up with confined pressure sensor 9.1, flow sensor 9.2, axial force sensor 9.3, temperature sensor 9.4, shaft position sensor 9.5 respectively on the data collecting instrument 9.6 and be connected, data collecting instrument 9.6 is connected with computing machine 9.7;
Confined pressure sensor 9.1 is arranged on the tensimeter 2.3;
Flow sensor 9.2 is arranged on the normal flow pump 1.3;
Axial force sensor 9.3 is arranged on the axial dynamometer 3.3;
Temperature sensor 9.4 is arranged on the temperature controller 4.3;
Shaft position sensor 9.5 is arranged on the dial gauge 8.1;
Be connected with data collecting instrument 9.6 by signal transmssion line respectively.
The function of data acquisition unit 9 is:
By confined pressure, the temperature in confined pressure sensor 9.1, temperature sensor 9.4 controls and the two pressure chambers 5 of measurement; Can draw respectively soil sample 0 real-time axial force and axial displacement by axial force sensor 9.3, shaft position sensor 9.5; The quality of water can be obtained absorbing or discharging in the soil sample 0 by flow sensor 9.2, and the volume change of triaxial test can be obtained simultaneously; Can obtain the volume change of unsaturated soil in the undrained shear process by differential pressure pick-up 6.
(1) the confined pressure sensor 9.1
Confined pressure sensor 9.1 is a kind of general parts, selects Senex production, pressure limit: 0～1Mpa, precision: 0.1%FS.Its function is: the confined pressure of measuring soil sample 0.
(2) flow sensor 9.2
Flow sensor 9.2 is a kind of general parts, selects Ponolflow-VA, measurement range :-5m/s～6.5m/s, resolution: 1mm/s, precision: 0.5%.Its function is: flow velocity, instantaneous delivery and the integrated flux of measuring solution.
(3) axial force sensor 9.3
Axial force sensor 9.3 is a kind of general parts, selects KAP-S type pull pressure sensor, and specification is: 5N～50kN.Its function is: the axle power of measuring soil sample 0.
(4) temperature sensor 9.4
Temperature sensor 9.4 is a kind of general parts, select Pt100 type platinum resistance (Beijing,
Its function is: measure soil sample 0 temperature of solution on every side.
(5) differential pressure pick-up 6
Differential pressure pick-up 6 is a kind of general parts, selects Senex production, pressure limit: 0～1Mpa, precision: 0.1%FS.Its function is: measure two pressure chamber's inner rooms and with reference to the pressure reduction of pipe, thereby can obtain the volume change value in soil sample 0 process of the test.
(6) shaft position sensor 9.5
Shaft position sensor 9.5 is a kind of general parts, selects ZKL-W type displacement transducer (LVDT), range 0～800mm, and diameter is
Its function is: the axial deformation of measuring soil sample 0 in the process of the test.
(7) data collecting instrument 9.6
Data collecting instrument 9.6 is a kind of general parts, the TSW-3 that selects Nanjing to produce.
(8) computing machine 9.7
The hardware configuration of computing machine 9.7 is: Intel (R) Celeron (R) CPU 420@1.6GHZ; The 512MB internal memory.
Its acquisition software adopts the Si Mingte data acquisition software SUPY1.0 of Si Mingte company exploitation.Data can be set, and are accurate to 0.1, can show in real time curve data.
Such as Fig. 4, its workflow is:
1. start acquisition software A;
2. setting data storing path B;
3. set acquisition interval time C;
4. turn-on data acquisition channel D;
5. input soil sample physical parameter E;
6. data zero clearing F;
7. begin to test G.
Two, test method
The present embodiment is take silt as example, and the process of the unsaturated soil triaxial test of using the utility model to circulate to apply suction is:
1. the installation of soil sample
Adopt static pressure method to make the cylindrical soil sample of three axle soil sample 0(by the dry density of setting and water percentage soil sample 0, be called for short soil sample), soil sample 0 is vacuumized saturated, the quality after weighing is saturated draws saturation moisture content and porosity.Then waterproof base plate 5.7 is put on pressure chamber's base 5.6, soil sample 0 is packed in the semi-permeable diaphragm 1.1, compacting is to get rid of the air in the film slightly, be installed in together on pressure chamber's base 5.6 with waterproof base plate 5.7, be placed with waterproof cover plate 5.8 on the top of soil sample 0, and then with elastic string semi-permeable diaphragm 5.1(semi-permeable diaphragm up and down be longer than the up and down two ends of soil sample in two ends) up and down two ends tighten respectively on the waterproof base plate 5.7 and waterproof cover plate 5.8 on pressure chamber's base 5.6;
2. adopt dialysis to apply needed suction
Be filled with certain density PEG solution 1.2 toward two pressure chambers inner room 5.1, the corresponding specific suction of each concentration, make solution 1.2 reach the position a little on the lower, top of inner room 5.1, then in mistress 5.2, inject certain lightweight oil 2.2, make lightweight oil 2.2 enter inner room, two Room liquid levels are combined;
3. test:
The native water characteristic curve of unsaturated soil under a, the test different temperatures
Set needed temperature by temperature control unit 4.Under different temperature, carry out the desorption wet test of soil sample 0.Every kind of temperature is all to concentration that PEG solution should be arranged and the calibration curve of suction.Corresponding to the every one-level suction value that sets, prepare the solution 1.2 of respective concentration.A suction duct 5.4 of 5 bottoms, two pressure chamber is opened, adopt normal flow pump 1.3 that solution 1.2 is full of two pressure chambers 5.After solution 1.2 is full of, open two suction ducts 5.4, the end that normal flow pump 1.3 is connected with inner room 5.1 is constantly supplied solution, and the other end constantly flows out.And discharge can Real-Time Monitoring, so just can obtain discharging in the soil sample 0 quality of water.When discharge was constant, then this grade suction reached balance, and logical oversaturated water cut can obtain water cut or the saturation degree of corresponding this one-level suction.Then the solution in two pressure chambers 5 is discharged, adopt above-mentioned same method to inject the solution 1.2 of next stage suction institute corresponding concentration.So repeatedly, test can not only obtain main drainage curve and main sucting wet curve, can also obtain the sweep trace of the inside simultaneously.Because soil sample 0 peripheral draining or suction, required equilibration time is short, can save like this time of whole test.
By temperature control unit 4, set the next stage temperature, repeat above-mentioned process of the test, can obtain native water characteristic relation complete under the different temperatures.
The native water characteristic curve of unsaturated soil under b, the different confined pressures of test
Corresponding to the every one-level suction value that sets, the solution 1.2 of preparation respective concentration.A suction duct 5.4 of 5 bottoms, two pressure chamber is opened, adopt normal flow pump 1.3 that solution is injected two pressure chambers inner room 5.1.When reaching the maximum scale line of inner room 5.1, stop to inject.Then the exhaust passage at 5 tops, two pressure chamber is opened, in pressure chamber 5, fill lightweight oil 2.2.Lightweight oil 2.2 and solution 1.2 have individual surface of contact at maximum scale line place.2 pairs of pressure chambers 5 apply the confined pressure that sets by the confined pressure unit.Open two suction ducts 5.4 in the inner room 5.1, the end that normal flow pump 1.3 is connected with inner room 5.1 is constantly supplied solution, and the other end constantly flows out.And discharge can Real-Time Monitoring, so just can obtain discharging or absorbing in the soil sample 0 quality of water.When discharge was constant, then this grade suction reached balance, and logical oversaturated water cut can obtain water cut or the saturation degree of corresponding this one-level suction.Then the solution 1.2 in two pressure chambers 5 and lightweight oil 2.2 are discharged, adopt above-mentioned same method to carry out the test of next stage suction.So repeatedly, test can not only obtain main drainage curve and main sucting wet curve, can also obtain the sweep trace of the inside simultaneously.Because soil sample 0 peripheral draining or suction, required equilibration time is short, can save like this time of whole test.
By confined pressure unit 2, set the next stage confined pressure, repeat above-mentioned process of the test, can obtain native water characteristic relation complete under the different confined pressures.
In conjunction with the desorption wet test of unsaturated soil under the top different temperatures, can control simultaneously confined pressure and temperature, obtain the complete native water characteristic curve of unsaturated soil under different temperatures and the different confined pressures.
C, carry out the consolidation test of unsaturated soil under the different suction
With the similar suction that sets that applies of b test, begin to apply confined pressure after the isoequilibrium.Normal flow pump 1.3 is supplied the solution 1.2 of respective concentration always, keeps solution 1.2 to contact at the maximum scale line with lightweight oil 2.2 always.Can obtain the variation of soil sample 0 volume by the fluctuations in discharge of normal flow pump 1.3 opposite sides of Real-Time Monitoring.
Then apply the next stage confined pressure, the process above repeating also can be done the test of unloading resilience simultaneously.The isotropic compression test of unsaturated soil under like this can controlled different suction.
Can also change temperature by temperature control unit 4 simultaneously, obtain the compression test under the different temperatures.
D, the three axle drainings of carrying out unsaturated soil under different suction and the different confined pressures and undrained shear test
Adopt previously described method to apply needed confined pressure and suction, carry out three axle draining and disdrainage tests of unsaturated soil.
Three not drainings of axle of unsaturated soil are cut soon: when soil sample 0 when confined pressure and suction reach balance, axial displacement surveymeter 8.2 contacts 8.1 zero clearings of displacement dial gauge with two pressure chambers 5.Starting characteristics test machine 3.4, lifting table 3.1 rises, and under different confined pressures soil sample 0 is carried out undrained quick shear test.Shear strain rate is selected according to different soil properties, can be with reference to normal triaxial.Measure inner room 5.1 and with reference to the pressure differential of managing 7, can obtain the body change of soil sample 0 by differential pressure pick-up 6.By data acquisition unit 9 can Real-time Collection axle power, axial displacement and body become.
Three axle draining shear tests of unsaturated soil: when soil sample 0 when confined pressure and suction reach balance, axial displacement surveymeter 8.2 contacts 8.1 zero clearings of displacement dial gauge with two pressure chambers 5.Starting characteristics test machine 3.4, lifting table 3.1 rises, and under different confined pressures soil sample 0 is carried out the draining shear test.Shear strain rate is selected according to different soil properties, can be with reference to normal triaxial.Measure inner room 5.1 and with reference to the pressure differential of managing 7, can obtain the body change of soil sample 0 by differential pressure pick-up 6.By data acquisition unit 9 can Real-time Collection axle power, axial displacement and body become.
As described above, can carry out the test under the different temperatures.
E, carry out the strength test of unsaturated soil under the different waterpower path
Different with saturated soil, the unsaturation property of soil is not only relevant with stress history, but also relevant with hydraulics history.For same suction, the hydraulics path that reaches this suction is different, also can cause different mechanical properties.Such as, reaching respectively the suction value of setting through dehumidification and moisture absorption path, the intensity of unsaturated soil is different with deformation characteristic under two kinds of paths.Therefore this device can carry out repeatedly the wet cyclic test of desorption, obtains the intensive parameter under the different waterpower path, for the later on development of unsaturated soil subject provides some experimental basis.
Claims (5)
1. a multifunctional circulation applies the unsaturated soil Triaxial tester of suction, comprises confined pressure unit (2), axle power applying unit (3) and axial displacement measuring unit (8);
It is characterized in that:
Be provided with suction applying unit (1), temperature control unit (4), two pressure chamber (5), differential pressure pick-up (6), reference pipe (7) and data acquisition unit (9);
Its annexation is:
Suction applying unit (1), confined pressure unit (2), axle power applying unit (3) are connected 4 with temperature control unit) be connected with two pressure chambers (5) respectively;
Differential pressure pick-up (6) is connected 8 with the axial displacement measuring unit) be connected with two pressure chambers (5) respectively, differential pressure pick-up (6) connects with the pipe of being connected (7);
Data acquisition unit (9) is connected 4 with confined pressure unit (2), axle power applying unit (3) with temperature control unit respectively) be connected;
Suction applying unit (1) is connected with data acquisition unit (9);
Differential pressure pick-up (6) is connected 8 with the axial displacement measuring unit) be connected with data acquisition unit (9) respectively.
2. apply the unsaturated soil Triaxial tester of suction by a kind of multifunctional circulation claimed in claim 1, it is characterized in that:
Described suction applying unit (1) comprises PEG solution (1.2) and the normal flow pump (1.3) of semi-permeable diaphragm (1.1), variable concentrations;
Semi-permeable diaphragm (1.1) parcel soil sample (0) is filled with certain density PEG solution (1.2) to two pressure chambers inner rooms (5.1), and corresponding suction is provided, and normal flow pump (1.3) links to each other with two pressure chamber's inner room (5.1) both sides;
Normal flow pump (1.3) links to each other with data acquisition unit (9) by signal transmssion line.
3. apply the unsaturated soil Triaxial tester of suction by a kind of multifunctional circulation claimed in claim 1, it is characterized in that:
Described temperature control unit (4) is a kind of general air conditioner structure, comprises resistance wire (4.1), compressor (4.2) and temperature controller (4.3);
Resistance wire (4.1) is built in the two mistress of pressure chamber (5.2) inwalls, and compressor (4.2) is communicated with two mistress of pressure chamber (5.2) by flexible pipe, and temperature controller (4.3) is connected 4.2 with resistance wire (4.1) with compressor respectively) be connected.
4. apply the unsaturated soil Triaxial tester of suction by a kind of multifunctional circulation claimed in claim 1, it is characterized in that:
Described pair of pressure chamber (5) comprises inner room (5.1), mistress (5.2), confined pressure duct (5.3), two suction ducts (5.4), exhaust passage (5.5), base (5.6), waterproof base plate (5.7) and waterproof cover plate (5.8);
Inner room (5.1) and mistress (5.2) are installed in respectively on the base (5.6), and the upper end open of inner room (5.1) is communicated with mistress (5.2);
Confined pressure duct (5.3) is arranged on the base (5.6) that is communicated with mistress (5.2);
One termination in two suction ducts (5.4) is arranged on the base (5.6) that is communicated with inner room (5.1), and another termination in two suction ducts (5.4) is communicated with normal flow pump (1.3);
Exhaust passage (5.5) is arranged on the top of two pressure chambers (5).
5. apply the unsaturated soil Triaxial tester of suction by a kind of multifunctional circulation claimed in claim 1, it is characterized in that:
Described data acquisition unit (9) comprises confined pressure sensor (9.1), flow sensor (9.2), axial force sensor (9.3), temperature sensor (9.4), shaft position sensor (9.5), data collecting instrument (9.6) and computing machine (9.7);
Have six input channels to be connected 6 with confined pressure sensor (9.1), flow sensor (9.2), axial force sensor (9.3), temperature sensor (9.4), shaft position sensor (9.5) with differential pressure pick-up respectively on the data collecting instrument (9.6)) be connected, the output terminal of data collecting instrument (9.6) is connected with computing machine 9.7;
Confined pressure sensor (9.1) is arranged on the tensimeter (2.3);
Flow sensor (9.2) is arranged on the normal flow pump (1.3);
Axial force sensor (9.3) is arranged on the axial dynamometer (3.3);
Temperature sensor (9.4) is arranged on the temperature controller (4.3);
Shaft position sensor (9.5) is arranged on the dial gauge (8.1).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220229007 CN202661326U (en) | 2012-05-21 | 2012-05-21 | Multifunctional unsaturated soil three-axis test device capable of circularly applying suction force |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220229007 CN202661326U (en) | 2012-05-21 | 2012-05-21 | Multifunctional unsaturated soil three-axis test device capable of circularly applying suction force |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102706728A (en) * | 2012-05-21 | 2012-10-03 | 中国科学院武汉岩土力学研究所 | Multifunctional unsaturated soil triaxial test device capable of circularly applying suction and method thereof |
| CN103091173A (en) * | 2013-01-14 | 2013-05-08 | 桂林理工大学 | Triaxial test apparatus of soil under water-soil chemical action and method thereof |
| CN103439203A (en) * | 2013-08-21 | 2013-12-11 | 国家电网公司 | Testing method for dynamic characteristic of soft soil under action of circulation load |
| CN104880371A (en) * | 2015-04-28 | 2015-09-02 | 中山大学 | Full-automatic multifunctional triaxial chuck |
| CN106153416A (en) * | 2016-06-27 | 2016-11-23 | 河北地质大学 | A kind of control moisture content, the clay sample preparation device of density and method for making sample simultaneously |
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2012
- 2012-05-21 CN CN 201220229007 patent/CN202661326U/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102706728A (en) * | 2012-05-21 | 2012-10-03 | 中国科学院武汉岩土力学研究所 | Multifunctional unsaturated soil triaxial test device capable of circularly applying suction and method thereof |
| CN102706728B (en) * | 2012-05-21 | 2014-07-30 | 中国科学院武汉岩土力学研究所 | Multifunctional unsaturated soil triaxial test device capable of circularly applying suction and method thereof |
| CN103091173A (en) * | 2013-01-14 | 2013-05-08 | 桂林理工大学 | Triaxial test apparatus of soil under water-soil chemical action and method thereof |
| CN103091173B (en) * | 2013-01-14 | 2015-07-15 | 桂林理工大学 | Triaxial test apparatus of soil under water-soil chemical action and method thereof |
| CN103439203A (en) * | 2013-08-21 | 2013-12-11 | 国家电网公司 | Testing method for dynamic characteristic of soft soil under action of circulation load |
| CN104880371A (en) * | 2015-04-28 | 2015-09-02 | 中山大学 | Full-automatic multifunctional triaxial chuck |
| CN104880371B (en) * | 2015-04-28 | 2017-11-10 | 中山大学 | The axle chuck of full-automatic multi-functional three |
| CN106153416A (en) * | 2016-06-27 | 2016-11-23 | 河北地质大学 | A kind of control moisture content, the clay sample preparation device of density and method for making sample simultaneously |
| CN106153416B (en) * | 2016-06-27 | 2018-09-14 | 河北地质大学 | It is a kind of at the same control moisture content, density clay sample preparation device and method for making sample |
| CN110325837A (en) * | 2017-02-27 | 2019-10-11 | 汤浅系统机器株式会社 | Deformation tester |
| CN110325837B (en) * | 2017-02-27 | 2022-04-01 | 汤浅系统机器株式会社 | Deformation tester |
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