CN104458424B - The real-time precision measurment device that in super large triaxial test, a kind of sample body becomes - Google Patents

Abstract

The invention discloses a real-time and precise measuring device for the volume change of a sample in a super-large triaxial test, which belongs to the technical field of mechanical engineering testing. It is characterized in that the device is composed of a servo motor, an electric cylinder, a water diversion tank, a drainage bucket, a slender glass measuring tube B, a right differential pressure sensor, a slender glass measuring tube A, a left differential pressure sensor, a weight plate and the like. According to the real-time height of the sample, the servo motor precisely controls the height of the water diversion groove on the drainage barrel to ensure that the height of the drain outlet is equal to the height of the middle part of the sample. The counterweight plate plays the role of balancing the weights of the glass tube support plate, the slender glass measuring tube B and the slender glass measuring tube A, so as to ensure that the drainage barrel does not tilt. The solenoid valve controls the slender glass measuring tube A and the slender glass measuring tube B to repeatedly and alternately feed/drain water to realize continuous and high-precision measurement of the displacement of super-large samples. The effects and benefits of the invention are: the device has a smart structure, a reasonable layout, and high measurement accuracy, which solves the problem of continuous high-precision measurement of displacement, and has good popularization value.

Description

A Real-time Accurate Measurement Device of Specimen Volume Change in Ultra-Large Triaxial Test

technical field

The invention belongs to the technical field of mechanical engineering testing, and relates to soil mechanics triaxial tests, in particular to a device for detecting the volume change (displacement) of a sample during an ultra-large triaxial test.

Background technique

To measure the strength and deformation of soils, triaxial testers are often used, which are widely used and can be used to measure a variety of parameters, including shear strength and deformation properties, consolidation characteristics and soil permeability. Its main functional equipment includes the control of the principal stress, the measurement of volume change (displacement) and pore pressure. The ultra-large triaxial tester is mainly aimed at completing large confining pressure and heavy load tests on ultra-large samples (cylindrical samples with a diameter of 1.0 meters and a height of 2.0 meters), testing the strength and deformation characteristics of super-large samples, and can complete the material characteristics of large-scale hydropower station earth-rock dams. Experiment work. During the test, the volume change of the sample was obtained by measuring the displacement. If the displacement is estimated at 10% of the sample volume, the displacement of a super large sample with a diameter of 1.0 meters and a height of 2.0 meters will reach 160L. It is very difficult to achieve real-time continuous and accurate measurement of such a large displacement.

At present, there is no real-time continuous and accurate measurement device for super-large sample volume change (displacement) in China. GDS, a well-known foreign manufacturer of geotechnical equipment, connects a specially designed flow sensor into the drainage pipeline to detect the volume change (discharge) of the sample. This kind of flow sensor is a patent owned by GDS company. Its measurement accuracy is not very high, it is expensive and not for sale, so it is difficult to buy in the market. In addition, for super large samples, in order to ensure the accuracy of displacement, it is necessary to ensure that the pressure in the middle of the sample is always equal to the atmospheric pressure. Since the height of the sample is generally as high as 2.0-2.5 meters, the deformation of the sample height can reach 400-500mm. Therefore, according to the dynamic deformation of the sample, it is necessary to dynamically adjust the height of the drain to ensure that the height of the drain is always equal to the middle position of the sample. Dynamically adjusting the height of the drain is also a problem that needs to be considered when large and ultra-large triaxial testers measure the volume change of the sample according to the displacement.

Contents of the invention

The purpose of the present invention is to provide a device for continuous and high-precision measurement of large displacement to solve the problem of accurately measuring the volume change of a sample according to the displacement in super-large triaxial tests.

The technical scheme adopted by the invention is: the device is composed of two subsystems: a subsystem for dynamically adjusting the height of the drain outlet and a subsystem for automatic and continuous detection of displacement. The dynamic adjustment subsystem of the height of the drain is mainly composed of an electric cylinder (servo motor, screw nut combination), a fixture, a drain bucket, a water diversion tank, and pipelines. The output shaft of the electric cylinder drives the drainage bucket to move up and down to ensure that the drainage outlet of the water diversion tank is always at the same height as the middle part of the sample. The height change of the sample during the test needs to be accurately measured, and the movement displacement of the drainage bucket can be precisely controlled according to the change of the sample height. The sub-system of automatic and continuous detection of drainage is used to detect the amount of water discharged from the drainage bucket, and the accurate detection of drainage can be realized by means of two slender glass measuring tubes. The thinner the glass measuring tube, the smaller the cross-sectional area, and the higher the accuracy of the measured displacement. The slender glass measuring tube is equipped with a high-precision differential pressure sensor. After static calibration, the displacement in the slender glass measuring tube can be accurately calculated according to the output voltage value of the differential pressure sensor.

The height dynamic adjustment subsystem of the drain outlet consists of a servo motor 1, an electric cylinder body 2, a water diversion tank 3, a two-way joint 4, a drain bucket 5, a right slider 7, a right guide rail 8, a right guide rail support plate 10, and a guide rail support rod 11 , system support column A12, flange plate 18, bucket cover 19, electric cylinder support plate 20, left guide rail support plate 21, left slider 22, left guide rail 25, system support column B26, system support column C32, system support column D33 and so on. The automatic and continuous detection subsystem of displacement consists of upper hose 6, right hose 9, slender glass measuring tube B13, glass tube support plate 14, right differential pressure sensor 15, right lower hose 16, and three-way joint with solenoid valve B17, tee joint with solenoid valve A23, left hose 24, slender glass measuring tube A27, left differential pressure sensor 28, lower left hose 29, tee joint with solenoid valve C30, weight plate 31, etc. composition.

Among them: system support column A12, system support column B26, system support column C32, system support column D33 are fixed on the ground, and support the dynamic adjustment subsystem of the fixed drain height. The drain bucket 5 is connected to the output shaft of the electric cylinder body 2, and the servo motor 1 accurately controls the height of the water diversion groove 3 on the drain bucket 5 according to the real-time height of the sample, ensuring that the height of the drain port is equal to the middle height of the sample. The right guide rail support plate 10 is used for fixing the right guide rail 8 , and the left guide rail support plate 21 is used for fixing the left guide rail 25 . Right slide block 7 and left slide block 22 are fixed on the drainage bucket 5. The guide rail support bar 11 is used for fixing the right guide rail support plate 10 and the left guide rail support plate 21 . The drainage bucket 5 can be fixed between the right guide rail 8 and the left guide rail 25 like this, and can slide freely up and down. The slender glass measuring tube B13 and the slender glass measuring tube A27 are fixed on the glass tube support plate 14, and the counterweight plate 31 plays a role of balancing the weight of the glass tube support plate 14, the slender glass measuring tube B13 and the slender glass measuring tube A27. Effect, ensured that drain barrel 5 does not tilt. Between the upper hose 6 and the right hose 9/left hose 24 is a three-way joint A23 with a solenoid valve, the right hose 9 is connected to the slender glass measuring tube B13, and the left hose 24 is connected to the slender glass measuring tube A27 is connected, and the three-way joint A23 with the electromagnetic valve realizes the conduction switching work with the slender glass measuring tube B13 and the slender glass measuring tube A27. The right differential pressure sensor 15 is installed under the elongated glass measuring tube B13, and the left differential pressure sensor 28 is installed under the elongated glass measuring tube A27. The right differential pressure sensor 15 and the left differential pressure sensor 28 are used to measure the size of the displacement in the elongated glass measuring tube B13 and the elongated glass measuring tube A27. The three-way joint B17 with the electromagnetic valve and the three-way joint C30 with the electromagnetic valve are connected with the slender glass measuring tube B13 and the slender glass measuring tube A27 through the lower right hose 16 and the lower left hose 29, and control their passage. Break to realize the function of draining outwards.

The effects and benefits of the present invention are: in order to realize the continuous high-precision measurement of the displacement, the dynamic adjustment subsystem of the height of the discharge outlet and the automatic continuous detection subsystem of the displacement are designed. The height dynamic adjustment subsystem of the drain can adjust the height of the drain in real time according to the height of the sample, so that the height of the drain is always equal to the middle of the sample. Since the drain is connected to the atmosphere, the pressure in the middle of the sample is equal to the atmospheric pressure, which ensures the accuracy of the effective stress of the sample skeleton. The sub-system of automatic and continuous detection of displacement uses two slender glass measuring tubes, and uses electromagnetic water valves and computer control to realize automatic switching, and completes high-precision continuous automatic measurement of displacement. The device has smart structure, reasonable layout and high measurement accuracy, which solves the problem of continuous high-precision measurement of displacement.

Description of drawings

Fig. 1 is a front view of the overall structure of a real-time and precise measurement device for volume change of a sample in a super-large triaxial test.

In the figure: 1 servo motor; 2 electric cylinder body; 3 water diversion tank; 4 two-way joint; 5 drain bucket; 6 upper hose; 7 right slider; 8 right guide rail; 9 right hose; ;11 Guide rail support rod; 12 System support column A; 13 Slender glass measuring tube B; 14 Glass tube support plate; 15 Right differential pressure sensor; 16 Right lower hose; 17 Tee joint B with solenoid valve; Flange; 19 bucket cover; 20 electric cylinder support plate; 21 left guide rail support plate; 22 left slider; 23 tee joint A with solenoid valve; 24 left hose; 25 left guide rail; 26 system support column B ; 27 slender glass measuring tube A; 28 left differential pressure sensor; 29 lower left hose; 30 tee joint C with solenoid valve.

Fig. 2 is a top view of the overall structure of a real-time and precise measurement device for sample volume change in a super-large triaxial test.

In the figure: 1 servo motor; 18 flange; 20 electric cylinder support plate.

Fig. 3 is a left view of the overall structure of a real-time and precise measurement device for sample volume change in a super-large triaxial test.

In the figure: 1 servo motor; 2 electric cylinder body; 3 water diversion tank; 4 two-way joint; 5 drainage bucket; 6 upper hose; 14 glass tube support plate; 18 flange; 21 left guide rail support plate; 22 left slider; 23 tee joint A with solenoid valve; 24 left hose; 25 left guide rail; 26 system support column B; 27 slender glass measuring tube A; 29 left lower soft 30 tee joint C with solenoid valve; 31 counterweight plate; 32 system support column C.

Fig. 4 is an axonometric view of the overall structure of a real-time and precise measurement device for sample volume change in a super-large triaxial test.

In the figure: 1 servo motor; 2 electric cylinder body; 3 water diversion tank; 4 two-way joint; 5 drain bucket; 6 upper hose; 10 right guide rail support plate; Long glass measuring tube B; 14 glass tube support plate; 15 right differential pressure sensor; 16 right lower hose; 17 tee joint B with solenoid valve; 19 bucket cover; 20 electric cylinder support plate; 22 left slider; 23 Tee joint A with solenoid valve; 24 Left hose; 26 System support column B; 27 Slender glass measuring tube A; 28 Left differential pressure sensor; 29 Lower left hose; 30 Tee joint with solenoid valve C; 31 counterweight plate; 32 system support column C; 33 system support column D.

detailed description

The specific embodiments of the present invention will be described in detail below in conjunction with the technical solutions and accompanying drawings.

As shown in attached drawings 1 to 4, the parts are cleaned with kerosene during assembly, and the mating surface is oiled after drying. The unprocessed surface of each part should be cleaned, the burrs should be removed, and the antirust paint should be dipped; the height of the drain is shown in Fig. 1 It consists of a dynamic adjustment subsystem and an automatic and continuous detection subsystem of displacement. The system support column A12, the system support column B26, the system support column C32, and the system support column D33 are fixed on the ground, and support the dynamic adjustment subsystem of the fixed drain height. The right guide rail support plate 10 fixes the right guide rail 8, and the left guide rail support plate 21 fixes the left guide rail 25. Right slide block 7 and left slide block 22 are fixed on the drainage bucket 5. The guide rail support bar 11 is used for fixing the right guide rail support plate 10 and the left guide rail support plate 21 . The drainage barrel 5 is fixed between the right guide rail 8 and the left guide rail 25, and can slide freely up and down. The drain bucket 5 is connected with the output shaft of the electric cylinder body 2 . During the test, the change of the height of the sample is dynamically detected, and the servo motor 1 accurately controls the height of the water diversion groove 3 on the drainage barrel 5 according to the real-time height of the sample, ensuring that the height of the drain outlet is equal to the height of the middle of the sample, so that the pressure in the middle of the sample It is equal to the atmospheric pressure, which ensures the accuracy of the sample drainage. The accuracy of the drainage is guaranteed, and the automatic continuous detection subsystem of the drainage is used to complete the automatic detection of the drainage.

The slender glass measuring tube B13 and the slender glass measuring tube A27 are fixed on the glass tube support plate 14, and the counterweight plate 31 plays a role of balancing the weight of the glass tube support plate 14, the slender glass measuring tube B13 and the slender glass measuring tube A27. Effect, ensured that drain barrel 5 does not tilt. The solenoid valve in the three-way joint A23 with solenoid valve controls the on-off of the drain through the upper hose 6 and the right hose 9 or the left hose 24. When the solenoid valve in the three-way joint A23 with a solenoid valve is energized, the upper hose 6 is connected to the right hose 9 and the slender glass measuring tube B13, and the drain water enters the slender glass measuring tube B13 and passes through the lower right hose. The differential pressure sensor 15 detects the volume of drain water flowing into the elongated glass burette B13. When the discharge of the elongated glass burette B13 approaches 90% of its range, de-energize the solenoid valve in the tee with solenoid valve A23. At this time, the drainage is conducted through the left flexible pipe 24 and the elongated glass measuring tube A27, and the draining water flows to the elongated glass measuring tube A27. At the same time, the solenoid valve in the three-way joint B17 with the solenoid valve is energized, and the slender glass measuring tube B13 realizes the outward drainage. One measurement. Likewise, when the drain of the slender glass burette A27 approaches 90% of its range, energize the solenoid valve in the tee with solenoid valve A23. At this time, the drainage is conducted through the right flexible pipe 9 and the elongated glass measuring tube B13, and the draining water flows to the elongated glass measuring tube B13. At the same time, the solenoid valve in the three-way joint C30 with a solenoid valve is energized, and the slender glass measuring tube A27 realizes outward drainage. One measurement. In this way, controlling the slender glass measuring tube A27 and the slender glass measuring tube B13 to repeatedly alternate water intake/drainage realizes the continuous high-precision measurement of the super large sample displacement.

The servo motor 1 in the electric cylinder adopts a high-precision position control servo motor, and the number of pulses is 10,000 per circle. The pitch of the lead screw is 5mm, which has high motion speed and position control accuracy, and can meet the measurement requirements. The sensing elements of the right differential pressure sensor 15 and the left differential pressure sensor 28 are adjusted to a signal voltage of 0-5V/10V, which is received by the data collector through 16-bit A/D conversion, and then the data collector transmits the result to the computer for The computer judges the 90% time nodes of the slender glass measuring tube B13 and the slender glass measuring tube A27, and controls the slender glass measuring tube A27 and the slender glass measuring tube B13 to alternately feed/drain water repeatedly. The number of pulses required by the servo motor 1 is calculated according to the height of the sample, and the height of the water diversion groove 3 on the drainage barrel 5 is precisely controlled to ensure that the height of the drain outlet is equal to the height of the middle part of the sample.

In addition, the counterweight plate 31 plays the role of balancing the weight of the glass tube support plate 14 , the elongated glass measuring tube B13 and the elongated glass measuring tube A27 , ensuring that the drain bucket 5 does not tilt. The measuring device has the advantages of smart structure, convenient operation, low manufacturing cost and high application value.

Claims (2)

1. the real-time precision measurment device that in super large triaxial test, a kind of sample body becomes, including servomotor (1), electricity Dynamic cylinder cylinder body (2), gutter (3), two pass joints (4), draining bucket (5), top hose (6), right cunning Block (7), right guide rail (8), right flexible pipe (9), right rail support plate (10), guide supporting rod (11), System support post A (12), slender glass buret B (13), glass tubing gripper shoe (14), right pressure difference sensing Device (15), bottom right flexible pipe (16), with the three way cock B (17) of electromagnetic valve, ring flange (18), bucket Lid (19), electric cylinder gripper shoe (20), left rail gripper shoe (21), left slider (22), with electricity The three way cock A (23) of magnet valve, left flexible pipe (24), left rail (25), system support post B (26), carefully Long buret A (27), left differential pressure pickup (28), lower-left flexible pipe (29), with the threeway of electromagnetic valve Joint C (30), Weight plate (31), system support post C (32), system support post D (33)；Its feature It is: system support post A (12), system support post B (26), system support post C (32), system support Post D (33) is fixed on ground, and supports the fixing highly dynamic adaptation system of discharge outlet；Draining bucket (5) Being connected with the output shaft of electric cylinder cylinder body (2), servomotor (1) is according to the real-time high precision of sample Control the height of the upper gutter (3) of draining bucket (5), it is ensured that discharge outlet height is equal with sample middle height； Right rail support plate (10) is used for fixing right guide rail (8), and left rail gripper shoe (21) is used for fixing a left side and leads Rail (25), right slide block (7) and left slider (22) are fixed on draining bucket (5), guide supporting rod (11) Being used for fixing right rail support plate (10) and left rail gripper shoe (21), draining bucket (5) is fixed on the right side leads Between rail (8) and left rail (25), and can freely up and down slide；Slender glass buret B (13) and thin Long buret A (27) is fixed on glass tubing gripper shoe (14), and Weight plate (31) plays balance glass tubing Gripper shoe (14), slender glass buret B (13) and the effect of slender glass buret A (27) weight, protect Card draining bucket (5) not run-off the straight；Between top hose (6) and right flexible pipe (9) and left flexible pipe (24) it is With the three way cock A (23) of electromagnetic valve, right flexible pipe (9) is connected with slender glass buret B (13), left Flexible pipe (24) is connected with slender glass buret A (27), and the three way cock A (23) with electromagnetic valve realizes With slender glass buret B (13), slender glass buret A (27) conducting switch operating；Right differential pressure pickup (15) being arranged on the lower section of slender glass buret B (13), left differential pressure pickup (28) is arranged on elongated The lower section of buret A (27), right differential pressure pickup (15) and left differential pressure pickup (28) are used for measuring The size of displacement in slender glass buret B (13) and slender glass buret A (27), with electromagnetic valve Three way cock B (17) and the three way cock C (30) with electromagnetic valve passes through bottom right flexible pipe (16) and lower-left Flexible pipe (29) is connected with slender glass buret B (13) and slender glass buret A (27), and it is logical to control it Break and realize outside drain function.

2. the method for the real-time precision measurment that a kind of sample body becomes in super large triaxial test, it is characterised in that: the method When being to obtain electric by the electromagnetic valve in the three way cock A (23) with electromagnetic valve, top hose (6) is soft with the right side The conducting of pipe (9), slender glass buret B (13), is drained into slender glass buret B (13)；By peace It is contained in the volume that the right differential pressure pickup in lower section (15) detection flows into the draining of slender glass buret B (13)； When the draining of slender glass buret B (13) is close to its range 90%, allow the three way cock A (23) with electromagnetic valve In electromagnetic valve power-off；Draining turns on slender glass buret A (27) through left flexible pipe (24), blowdown stream To slender glass buret A (27), allow the solenoid valves in the three way cock B (17) with electromagnetic valve, Slender glass buret B (13) realizes outside draining, and draining terminates the relief three way cock B with electromagnetic valve (17) the electromagnetic valve power-off in, waits and measuring next time；The draining of slender glass buret A (27) is close to it During range 90%, allowing the solenoid valves in the three way cock A (23) with electromagnetic valve, draining is through right soft Pipe (9) turns on slender glass buret B (13), and draining flows to slender glass buret B (13)；Allow band Having the solenoid valves in the three way cock C (30) of electromagnetic valve, slender glass buret A (27) outwards realizes Draining, draining terminates the electromagnetic valve power-off in the relief three way cock C (30) with electromagnetic valve, waits next Secondary measurement；Control slender glass buret A (27) and slender glass buret B (13) is alternately and repeatedly intake/arranged Water achieves the continuous precise of super large sample displacement and measures.