A control and data acquisition system based on triaxial shear test

Abstract

The application discloses a control and data acquisition system based on triaxial shear test, belongs to the technical field of geotechnical mechanics characteristic side view, and is composed of an external test device, a confining pressure system and a pore pressure measuring system, wherein the test device comprises a base, a pressure chamber and an axial pressure head which are connected in a matching mode, injection devices for injecting medium into the pressure chamber are arranged on the lateral sides of the test device, the injection devices comprise temperature insulation chambers, heating elements capable of heating fluid are arranged in the temperature insulation chambers, the heating elements are connected with buffer elements, rubber columns are symmetrically fixed to the base, reinforcing columns are fixed to the pressure chamber and are inserted into the rubber columns, limiting elements are arranged above the pressure chamber, the limiting elements comprise pneumatic control pistons and annular rings which are clamped with the axial pressure head, the application can not only obtain rock and soil strength characteristic data at multiple temperatures, but also can reduce experimental errors caused by installation in multiple aspects, the device is low in cost and stable and reliable in test results.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical mechanical properties side-view technology, specifically relating to a control and data acquisition system based on triaxial shear tests. Background Technology

[0002] A triaxial apparatus is a device used for rock sample testing. It can check various parameters of the rock sample and apply circumferential pressure as well as vertical axial pressure to the sample, thus enabling rock sample testing. Currently, traditional triaxial apparatuses mainly consist of a pressure-bearing cylinder. The prepared rock sample is loaded into the cylinder, and circumferential pressure is applied to the sample via hydraulic pressure. Simultaneously, vertical pressure is applied via a lifting pressurization device. The rock sample is subjected to both circumferential and axial pressure, causing deformation and even failure, thereby achieving the test and obtaining the rock sample's parameters.

[0003] In existing triaxial instruments, the difference in operator skill level during installation may cause the specimen to shift relative to the base specimen axis, resulting in uneven stress on the specimen when subjected to confining pressure and axial shear force. This affects the value of the peak value of the principal stress difference versus axial strain curve, ultimately causing experimental errors.

[0004] US Patent Publication No. US20150061669A1 discloses a triaxial nuclear magnetic resonance (NMR) testing instrument, including a triaxial load frame surrounding a triaxial pressure measuring element. The triaxial pressure measuring element includes a triaxial sample holder, at least one electrical sensor, at least one acoustic sensor, and an NMR instrument. This invention applies triaxial pressure by loading the triaxial sample holder into the triaxial force sensor and contacting it with the end cap of the triaxial NMR device. Fluid flow through the end cap to the space surrounding the triaxial sample holder applies triaxial pressure, and the fluid is controlled by temperature provided by the outer space of the triaxial sample holder. This invention enables the testing of the static mechanical properties of samples, is suitable for various sample sizes, and can identify hydrate structures, exhibiting broad applicability. However, the invention has room for improvement in the following technical aspects: sample placement is easily misaligned due to vibration and installation offset, resulting in large and inaccurate test data; controlling temperature changes can easily cause irreversible damage to the triaxial sample holder, and long-term use may destroy the holder. Summary of the Invention

[0005] The purpose of this invention is to provide a control and data acquisition system based on triaxial shear test that can measure data under various temperature conditions and improve installation stability to reduce experimental errors.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0007] A control and data acquisition system based on triaxial shear test, comprising: an external frame, a test device is arranged in the external frame, an injection device is arranged on the side of the test device, the test device comprises a base, a pressure chamber is connected with the base, and a pressure head is arranged on the top of the pressure chamber and matched with the external frame. After the pressure chamber is installed on the base to form a pressure chamber, the injection assembly can inject compressed oil for test into the pressure chamber, the mechanical properties of the rock and soil are determined by applying confining pressure to the pressure chamber and applying axial pressure to the rock and soil sample through the pressure head matched with the external frame.

[0008] Preferably, the injection device comprises a temperature insulation chamber in communication with the pipeline of the pressure chamber at the top, an oil liquid controller in communication with the pipeline at the bottom of the temperature insulation chamber, and heating elements symmetrically arranged in the temperature insulation chamber. The oil liquid controller comprises a compressed oil tank and a pump body, the compressed oil is injected into the temperature insulation chamber by controlling the pump body, the oil liquid is heated by the heating elements in the temperature insulation chamber and delivered to the pressure chamber, the temperature of the rock and soil sample is changed from the surrounding temperature environment, and the mechanical properties of the rock and soil under different temperature conditions are realized.

[0009] Preferably, the heating element comprises a spherical heating base near the end of the temperature insulation chamber, a plurality of heating bases are fixed with connecting rods at the proximal end, heating wires are arranged on the heating bases, a controller is fixed on the outer wall of the temperature insulation chamber, and a plurality of heating wires are connected with the controller. The controller can adjust the heating efficiency of the heating wires, thereby adjusting and controlling the temperature of the oil liquid, realizing multi-temperature measurement data, the spherical heating base and the connecting rod can guide the oil liquid injected into the top of the temperature insulation chamber and the oil liquid flowing out of the temperature insulation chamber, reduce the heat exchange contact probability of the oil liquid and the wall of the temperature insulation chamber, reduce the heat loss of the oil liquid, which is conducive to improving the heating efficiency, and the oil liquid guided by the spherical surface of the heating base is heated by the closely arranged heating wires, which can further improve the heat balance, ensure the stable temperature of the fluid entering the pressure chamber, and reduce the experimental error caused by temperature.

[0010] Preferably, a buffer is arranged in the temperature insulation chamber, the buffer comprises an upper pressing plate and a lower pressing plate respectively fixed with upper and lower connecting rods at the ends, the lower pressing plate is fixed with the inner wall of the temperature insulation chamber, and the upper pressing plate is axially spaced apart from the lower pressing plate and connected with a spring therebetween. When the flow rate of the oil liquid entering the temperature insulation chamber is too large, the oil liquid impacts the upper heating base and drives the upper pressing plate to extrude the spring through the upper connecting rod, so that the upper heating element axially slides in the temperature insulation chamber, realizing the buffering of oil liquid with different flow rates, avoiding the backflow caused by the impact of the oil liquid, reducing the test error caused by the change of the initial pressure, and balancing the stress when the upper pressing plate and the lower pressing plate are in contact with the fluid, which can ensure the perpendicularity of the heating element sliding in the temperature insulation chamber and further improve the fluid guiding effect.

[0011] Preferably, the upper pressing plate is fixed with an upper convex ring at the edge of the lower end surface, the lower pressing plate is fixed with a lower convex ring at the edge of the upper end surface, and the upper convex ring can axially slide in the inner side of the lower convex ring.

[0012] Preferably, the upper pressing plate is provided with upper through holes around, the lower pressing plate is provided with lower through holes around, and the upper through holes and the lower through holes are staggered. When the oil liquid flow rate into the temperature insulation bin is slow, the upper pressing plate is spaced apart from the lower pressing plate, the oil liquid can flow from the edge line of the upper pressing plate to the lower pressing plate, and then flow out from the through holes of the lower pressing plate; when the oil liquid flow rate is too fast, the upper pressing plate is impacted by the fluid to drive the upper convex ring to extrude the spring, at this time, the upper convex ring slides in the lower convex ring until the upper convex ring abuts against the end surface of the lower pressing plate, and the upper pressing plate, the lower pressing plate, the upper convex ring and the lower convex ring form a cavity, at this time, the oil liquid can only enter the cavity through the upper through holes, and then flow out from the lower through holes under the extrusion of the oil liquid, which delays the flow rate of the oil liquid above the upper pressing plate, can avoid experimental errors caused by the oil liquid not being effectively heated due to the too fast flow rate, and can ensure that the oil liquid controller can stop oil injection in time to avoid excessive oil liquid to press the rock-soil sample to cause deformation and scrap, and the oil liquid above the upper pressing plate is continuously heated by the upper heating member to realize heat balance, reduce the formation of bubbles in the oil liquid, improve the stability of the air pressure in the pressure bin, and improve the accuracy of the measured data.

[0013] Preferably, rubber columns are symmetrically fixed on the base, reinforcing columns are symmetrically fixed outside the pressure bin, the reinforcing columns are provided with insertion holes matched with the rubber columns, the pressure bin is provided with air vent grooves in communication with the insertion holes, and the air vent grooves are provided with mounting holes in communication with the outside. The test personnel inserts the rubber columns into the insertion holes of the reinforcing columns to realize the assembly of the pressure bin and the base, which not only improves the installation speed, but also avoids the vibration caused by moving the pressure bin during alignment during installation, causes the rock-soil sample to relatively tilt and deviate on the base, and affects the peak value of the relationship curve between the principal stress difference and the axial strain, resulting in experimental errors. After the rubber columns are inserted into the insertion holes, the gas in the insertion holes is slowly discharged to the outside through the air vent grooves and the mounting holes, the sliding speed of the rubber columns relative to the insertion holes is limited by the gas pressure, the vibration of the rock-soil sample caused by the rapid falling of the pressure bin during installation is avoided, the experimental errors are further reduced, and the rubber columns can absorb the weak vibration of the external frame through the rubber material to improve the accuracy of the test data.

[0014] Preferably, a limiting piece is arranged in the mounting hole, the limiting piece includes a gas cavity fixed in the mounting hole, and a piston is slidably arranged in the gas cavity. A plurality of pistons are fixed with a same ring arranged on the pressure head, and the pressure head is fixed with a clamping ring clamped with the ring. When the rubber column is inserted, the gas in the mounting hole enters the gas cavity and pushes the piston to slide upward in the gas cavity. The plurality of pistons drive the ring to slide axially on the pressure head and abut against the clamping ring, realizing the clamping and limiting of the pressure head during installation of the pressure bin, avoiding the test personnel from colliding with the rock-soil sample by not lifting the pressure head during installation of the pressure bin, causing the pressure head to exert an initial pressure on the rock-soil sample and causing experimental errors. At the same time, the ring can also correct the perpendicularity of the pressure head relative to the rock-soil sample to ensure the stress balance during pressing and improve the reliability of the measured data.

[0015] Preferably, the piston is provided with a first air hole at the shaft position, the circular ring is provided with a plurality of second air holes, the first air hole and the second air hole are arranged in position correspondence and are in communication. When the external frame abuts and presses the pressure head, the pressure head drives the clamped circular ring to move downward, the circular ring drives the piston to move downward and extrudes the gas in the air cavity, the gas is discharged upward from the first air hole and the second air hole, the discharge of the gas in the air cavity from the first air hole and the second air hole is slow, the downward speed of the pressure head can be effectively buffered, the external frame can be stopped when the pressure head contacts the rock-soil sample, the initial axial load applied by the pressure head is avoided, the subsequent pressure head can apply load to the rock-soil sample with a preset value, and the test accuracy is improved.

[0016] Preferably, the external frame is provided with a confining pressure system and a pore pressure measurement system laterally, the confining pressure system is in communication with the inside of the pressure chamber, the base is provided with a rubber sleeve, the rubber sleeve is sequentially provided with a top cap, a sample and a water-permeable stone from top to bottom, and the pore pressure measurement system is connected to the bottom of the water-permeable stone.

[0017] The injection device for stabilizing the oil liquid temperature and the rubber column and the limiting piece which can be easily installed are adopted, so that the following beneficial effects are achieved: the heating piece guides the oil liquid through the heating base and the connecting rod, reduces the heat loss of the oil liquid, improves the heating efficiency of the electric heating wire on the oil liquid, improves the accuracy of the environment temperature in the pressure chamber, and reduces the data deviation; the upper and lower pressure plates which can slide relatively realize the displacement of the heating piece, so that the heating piece can adaptively adjust the height position according to the flow rate to buffer the oil liquid, reduce the negative pressure of the backflow instrument, ensure the initial stress-free state of the rock-soil layer, and improve the test precision; the upper and lower convex rings form a chamber and throttle the oil liquid, improve the heat balance, reduce the oil liquid bubbles, and further ensure the stability of the pressure in the chamber; the limiting piece realizes the limiting of the pressure head during installation through the rubber column, which not only facilitates the alignment and installation of the pressure chamber, but also avoids the experimental error caused by the operation error of the installer; the circular ring improves the verticality of the pressure head during downward pressing, ensures the uniform distribution of the load on the rock-soil sample; the first and second air holes slow down the downward pressing speed of the pressure head, which is beneficial to ensure that the pressure head contacts the rock-soil sample without extrusion and reduces the experimental error. Therefore, the control and data acquisition system based on the triaxial shear test can measure data under various temperature conditions and improve the installation stability to reduce the experimental error. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic view of the position arrangement of the test device and the external frame;

[0019] Figure 2 It is a schematic view of the external frame;

[0020] Figure 3 It is a schematic view of the internal structure of the test device;

[0021] Figure 4 is a schematic view of the inside of the temperature insulation bin;

[0022] Figure 5 is a schematic view of the heating element;

[0023] Figure 6 is a schematic view of the buffer element;

[0024] Figure 7 is a schematic view of the reinforcing column;

[0025] Figure 8 is a schematic view of the limiting element;

[0026] Figure 9 is Figure 8 is an enlarged schematic view of area A in the middle.

[0027] Fig. 1 is a schematic view of the external frame; Fig. 2 is a schematic view of the bottom plate; Fig. 3 is a schematic view of the guide shaft; Fig. 4 is a schematic view of the top plate; Fig. 5 is a schematic view of the pressurizing system; Fig. 6 is a schematic view of the air cylinder; Fig. 7 is a schematic view of the force measuring ring; Fig. 8 is a schematic view of the test device; Fig. 9 is a schematic view of the base; Fig. 10 is a schematic view of the pressure bin; Fig. 11 is a schematic view of the pressure head; Fig. 12 is a schematic view of the injection device; Fig. 13 is a schematic view of the temperature insulation bin; Fig. 14 is a schematic view of the oil controller; Fig. 15 is a schematic view of the heating element; Fig. 16 is a schematic view of the heating base; Fig. 17 is a schematic view of the connecting rod; Fig. 18 is a schematic view of the heating wire; Fig. 19 is a schematic view of the controller; Fig. 20 is a schematic view of the buffer element; Fig. 21 is a schematic view of the upper pressing plate; Fig. 22 is a schematic view of the lower pressing plate; Fig. 23 is a schematic view of the spring; Fig. 24 is a schematic view of the upper protruding ring; Fig. 25 is a schematic view of the lower protruding ring; Fig. 26 is a schematic view of the upper through hole; Fig. 27 is a schematic view of the lower through hole; Fig. 28 is a schematic view of the rubber column; Fig. 29 is a schematic view of the reinforcing column; Fig. 30 is a schematic view of the insertion hole; Fig. 31 is a schematic view of the air passage groove; Fig. 32 is a schematic view of the mounting hole; Fig. 33 is a schematic view of the limiting element; Fig. 34 is a schematic view of the air cavity; Fig. 35 is a schematic view of the piston; Fig. 36 is a schematic view of the circular ring; Fig. 37 is a schematic view of the snap ring; Fig. 38 is a schematic view of the first air hole; Fig. 39 is a schematic view of the second air hole; Fig. 40 is a schematic view of the confining pressure system; Fig. 41 is a schematic view of the pore pressure measuring system; Fig. 42 is a schematic view of the rubber sleeve; Fig. 43 is a schematic view of the top cap; Fig. 44 is a schematic view of the test sample; and Fig. 45 is a schematic view of the water-permeable stone. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be further described in detail below in combination with the specific embodiments and the drawings:

[0029] Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor shall fall within the protection scope of the present application.

[0030] Reference is made to the accompanying drawings Figure 1 - the accompanying drawings Figure 3 A control and data acquisition system based on triaxial shear test, comprising: an external frame 1, the external frame 1 is internally provided with a test device 2, the test device 2 is provided with an injection device 3 on the side, the test device 2 comprises a base 20, the base 20 is connected with a pressure bin 21 in a matching manner, and the pressure bin 21 is provided with a pressure head 22 on the top of the external frame 1 in a matching manner.

[0031] The outer frame 1 comprises a bottom plate 10, a plurality of guide shafts 11 are symmetrically arranged on the upper end face of the bottom plate 10, a top plate 12 is arranged in parallel above the bottom plate 10, the plurality of guide shafts 11 are fixed at the end and the bottom end of the top plate 12, a gas cylinder 13 capable of being controlled to extend and retract is arranged at the center of the bottom end of the top plate 12, a force ring 14 for measuring the bottom pressure is connected to the extension end of the gas cylinder 13, the force ring 14 is arranged above the pressure head 22, and the base 20 is fixed to the upper end face of the bottom plate 10 and located between the plurality of guide shafts 11. By controlling the extension and retraction of the gas cylinder 13 to drive the force ring 14 to abut against the pressure head 22, the data measurement of the axial load below the pressure head 22 is realized.

[0032] After the base 20 is installed on the pressure chamber 21 to form a pressure chamber, the injection assembly can inject compressed oil for testing into the pressure chamber, and by applying confining pressure to the pressure chamber and by the outer frame 1 cooperating with the pressure head 22 to apply axial pressure to the rock-soil sample, the mechanical property measurement of the rock-soil is realized.

[0033] Referring to the accompanying drawings Figure 4 - the accompanying drawings Figure 5 , the injection device 3 comprises a temperature insulation chamber 30 at the top of which the pipeline of the pressure chamber 21 is communicated, the oil liquid controller 31 is communicated by pipeline at the bottom of the temperature insulation chamber 30, and the heating element 4 is symmetrically arranged in the temperature insulation chamber 30.

[0034] It should be noted that the oil liquid controller 31 comprises a compressed oil tank, a pump body connected to the compressed oil tank, and a control terminal capable of controlling the output rate of the pump body.

[0035] The pump body is controlled by the control terminal to inject compressed oil into the temperature insulation chamber 30, the oil liquid is heated by the heating element 4 in the temperature insulation chamber 30 and delivered to the pressure chamber 21, the temperature of the rock-soil sample is changed from the surrounding temperature environment, and the mechanical properties of the rock-soil under different temperature conditions are realized.

[0036] Referring to the accompanying drawings Figure 5 The heating element 4 comprises a spherical heating base 40 close to the end of the temperature insulation chamber 30, a plurality of heating bases 40 are fixed with a connecting rod 41 at the similar end, a heating wire 42 is arranged on the heating base 40, a controller 43 is fixed on the outer wall of the temperature insulation chamber 30, and a plurality of heating wires 42 are connected with the controller 43.

[0037] The controller 43 can adjust the heating efficiency of the heating wire, thereby adjusting and controlling the temperature of the oil liquid, realizing the measurement data of multiple temperatures, the spherical heating base 40 and the connecting rod 41 can guide the oil liquid injected into the top of the temperature insulation chamber 30 and flowing out of the temperature insulation chamber 30, reduce the contact probability of heat exchange between the oil liquid and the wall of the temperature insulation chamber 30, reduce the heat loss of the oil liquid, which is conducive to improving the heating efficiency, and the oil liquid guided by the connecting rod 41 is heated by the heating wire 42 closely arranged on the spherical surface of the heating base 40, which can further improve the uniformity of heat, ensure the stable temperature of the fluid entering the pressure chamber 21, and reduce the experimental error caused by temperature.

[0038] The buffer 5 is arranged in the temperature insulation bin 30, and the buffer 5 comprises an upper pressing plate 50 and a lower pressing plate 51 which are respectively fixed at the end portions of the upper and lower connecting rods 41, the lower pressing plate 51 is fixed to the inner wall of the temperature insulation bin 30, and the upper pressing plate 50 is arranged axially spaced from the lower pressing plate 51 and connected with the spring 52 therebetween. When the flow rate of the oil liquid entering the temperature insulation bin 30 is too large, the oil liquid impacts the heating base 40 at the upper side and drives the upper pressing plate 50 to extrude the spring 52 through the upper connecting rod 41, so that the upper heating element 4 axially slides in the temperature insulation bin 30, the buffer for the oil liquid with different flow rates is realized, the backflow caused by the excessive impact of the oil liquid on the pressure bin 21 is avoided, the test error caused by the change of the initial pressure is reduced, the stress balance of the upper pressing plate 50 and the lower pressing plate 51 when being in contact with the fluid is ensured, the verticality of the sliding of the heating element 4 in the temperature insulation bin 30 is ensured, and the fluid drainage effect is further improved.

[0039] Referring to the accompanying drawings Figure 6 The upper pressing plate 50 is fixed with an upper convex ring 53 at the edge of the lower end face, the lower pressing plate 51 is fixed with a lower convex ring 54 at the edge of the upper end face, and the upper convex ring 53 can axially slide inside the lower convex ring 54.

[0040] The upper pressing plate 50 is arranged with an upper through hole 55, the lower pressing plate 51 is arranged with a lower through hole 56, and the upper through hole 55 and the lower through hole 56 are staggered. When the flow rate of the oil liquid injected into the temperature insulation bin 30 is slow, the upper pressing plate 50 is spaced from the lower pressing plate 51, the oil liquid can flow from the edge line of the upper pressing plate 50 to the lower pressing plate 51, and then flow out from the through hole of the lower pressing plate 51, when the flow rate of the oil liquid is too fast, the upper pressing plate 50 is driven by the fluid impact to extrude the spring 52 through the upper convex ring 53, at this time, the upper convex ring 53 slides in the lower convex ring 54 until the upper convex ring 53 abuts against the end face of the lower pressing plate 51, the upper pressing plate 50, the lower pressing plate 51, the upper convex ring 53 and the lower convex ring 54 form a cavity, at this time, the oil liquid can only enter the cavity through the upper through hole 55, and then be discharged from the lower through hole 56 under the extrusion of the oil liquid, the flow rate of the oil liquid above the upper pressing plate 50 is delayed, the experimental error caused by the oil liquid not being effectively heated due to the too fast flow rate can be avoided, the oil liquid controller 31 can be ensured to stop injecting oil in time, the excessive oil liquid can be avoided to press the rock-soil sample to cause its deformation and scrap, the oil liquid above the upper pressing plate 50 is continuously heated by the upper heating element 4 to realize the heat balance, the formation of the bubbles in the oil liquid is reduced, the stability of the air pressure in the pressure bin 21 is improved, and the accuracy of the measured data is improved.

[0041] Referring to the accompanying drawings Figure 7 - the accompanying drawings Figure 8The rubber column 6 is symmetrically fixed on the base 20, the reinforcing column 60 is symmetrically fixed on the outer side of the pressure chamber 21, the reinforcing column 60 is provided with the insertion hole 61 matched with the rubber column 6, the pressure chamber 21 is provided with the air vent groove 62 communicated with the insertion hole 61, and the air vent groove 62 is provided with the mounting hole 63 communicated with the outside. The test personnel realizes the assembly of the pressure chamber 21 and the base 20 by inserting the rubber column 6 into the insertion hole 61 of the reinforcing column, which not only improves the installation speed, but also avoids the vibration caused by moving the pressure chamber 21 during installation, so as to avoid the relative inclination of the rock-soil sample 92 on the base 20, affect the peak value of the relationship curve of the principal stress difference and the axial strain, cause the experimental error, and improve the test data accuracy. After the rubber column 6 is inserted into the insertion hole 61, the gas in the insertion hole 61 is slowly discharged to the outside through the air vent groove 62 and the mounting hole 63, the sliding speed of the rubber column 6 relative to the insertion hole 61 is limited by the air pressure, the vibration of the rock-soil sample 92 caused by the rapid falling of the pressure chamber 21 during installation is avoided, the experimental error is further reduced, the weak vibration of the external frame 1 is absorbed by the rubber column 6, and the test data accuracy is improved.

[0042] Referring to the accompanying drawings Figure 9 The limiting piece 7 is arranged in the mounting hole 63, the limiting piece 7 comprises the air cavity 70 fixed in the mounting hole 63, the piston 71 is arranged in the air cavity 70 in a sliding mode, a plurality of pistons 71 are fixed with the same ring arranged on the pressure head 22, and the pressure head 22 is fixed with the snap ring 73 clamped with the ring. When the rubber column 6 is inserted, the gas in the mounting hole 63 enters the air cavity 70 and pushes the piston 71 to slide upwards in the air cavity 70, the plurality of pistons 71 drive the ring to slide axially on the pressure head 22 and abut against the snap ring 73, the snap ring 73 is clamped and limited on the pressure head 22 during the installation of the pressure chamber 21, the rock-soil sample is not collided by the pressure head 22 during the installation of the pressure chamber 21, the initial pressure of the pressure head 22 on the rock-soil sample is avoided, the experimental error is avoided, the perpendicularity of the pressure head 22 relative to the rock-soil sample is also corrected by the ring, the stress balance during the pressing is ensured, the reliability of the measured data is improved, and the test data accuracy is improved.

[0043] The piston 71 is provided with the first gas hole 74 at the axial position, the ring is provided with a plurality of second gas holes 75, the first gas hole 74 and the second gas hole 75 are arranged in a position corresponding mode and are communicated. When the external frame 1 abuts against and presses the pressure head 22, the pressure head 22 drives the clamped ring to move downwards through the snap ring 73, the ring drives the piston 71 to move downwards and extrudes the gas in the air cavity 70, the gas is discharged upwards from the first gas hole 74 and the second gas hole 75, the normal pressing of the pressure head 22 is ensured by discharging the gas in the air vent groove 62, the discharging speed of the gas in the air cavity 70 from the first gas hole and the second gas hole is slow, the downward speed of the pressure head 22 can be effectively buffered, the external frame 1 can be stopped when the pressure head 22 contacts the rock-soil sample 92, the axial initial load of the pressure head 22 is avoided, the subsequent pressure head 22 can apply the load to the rock-soil sample with a preset value, the test accuracy is improved, and the test data accuracy is improved.

[0044] Referring to the accompanying drawingsFigure 3 The outer frame 1 is provided with a confining pressure system 8 and a pore pressure system 9 on the side, the confining pressure system 8 is communicated with the inside of the pressure chamber 21, the base 20 is provided with a rubber sleeve 90, the rubber sleeve 90 is sequentially provided with a top cap 91, a sample 92 and a water permeable stone 93 from top to bottom, and the pore pressure system 9 is connected to the bottom of the water permeable stone 93. The water permeable stone 93, the sample 92 and the top cap 91 are sequentially placed on the base 20 from bottom to top, so that the sample 92 is coaxial with the axis of the base 20, the rubber sleeve is sleeved on the outside of the sample 92 and is tightly sleeved with the base 20 at the bottom, the pressure chamber 21 is installed on the base 20, after the pressure chamber 21 is injected with the compressed oil of the preset temperature, the preset pressure value is applied to the pressure chamber 21 through the confining pressure system 8, the air cylinder 13 is controlled to push the pressure head 22 to apply the axial load to the top cap 91, the sample 92 is internally extruded under the triaxial shear force, and the value at the bottom of the water permeable stone 93 is measured through the pore pressure system 9, so that the mechanical property of the rock and soil is measured.

[0045] It will be obvious to a person skilled in the art that, without departing from the spirit or essential characteristics of the application, the present application can be implemented in other specific forms. The present examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the description given above, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claim.

Claims

1. A triaxial shear test based control and data acquisition system comprising: An external frame (1) is provided inside the external frame (1), and an injection device (3) is provided on the side of the test device (2). Its features are: the test device (2) includes a base (20), the base (20) is connected to a pressure chamber (21), and the pressure chamber (21) is fitted with a pressure head (22) on the top of the outer frame (1). The injection device (3) includes an insulated chamber (30) whose top is connected to the pressure chamber (21) via a pipe. Heating elements (4) are symmetrically arranged inside the insulated chamber (30). The heating element (4) includes a spherical heating base (40) near the end of the heat insulation chamber (30), and a plurality of the heating bases (40) are fixed with connecting rods (41) at adjacent ends. The insulation chamber (30) is equipped with a buffer (5), which includes an upper pressure plate (50) and a lower pressure plate (51) fixed to the ends of the upper and lower connecting rods (41) respectively. The lower pressure plate (51) is fixed to the inner wall of the insulation chamber (30). The upper pressure plate (50) and the lower pressure plate (51) are axially spaced apart and connected by a spring (52). The upper pressure plate (50) is surrounded by an upper through hole (55), and the lower pressure plate (51) is surrounded by a lower through hole (52). Through hole (56), the upper through hole (55) and the lower through hole (56) are arranged alternately, the upper pressure plate (50) has an upper convex ring (53) fixed at the lower end edge, the lower pressure plate (51) has a lower convex ring (54) fixed at the upper end edge, the upper convex ring (53) can slide axially inside the lower convex ring (54), when the oil speed is too fast, the upper pressure plate (50), the lower pressure plate (51), the upper convex ring (53) and the lower convex ring (54) form a cavity.

2. The control and data acquisition system based on triaxial shear test according to claim 1, characterized in that: The bottom pipe of the insulated compartment (30) is connected to an oil controller (31).

3. The control and data acquisition system based on triaxial shear test of claim 1, wherein: Heating wires (42) are arranged on the heating substrate (40), and a controller (43) is fixed on the outer wall of the heat insulation chamber (30). Multiple heating wires (42) are connected to the controller (43).

4. The control and data acquisition system based on triaxial shear test of claim 1, wherein: Rubber columns (6) are symmetrically fixed on the base (20), and reinforcing columns (60) are symmetrically fixed on the outside of the pressure chamber (21). The reinforcing columns (60) have insertion holes (61) that cooperate with the rubber columns (6). The pressure chamber (21) has a ventilation groove (62) that communicates with the insertion holes (61). The ventilation groove (62) is provided with mounting holes (63) that communicate with the outside.

5. A control and data acquisition system based on triaxial shear test according to claim 4, characterized in that: The mounting hole (63) is provided with a limiting member (7), the limiting member (7) includes an air cavity (70) fixed in the mounting hole (63), a piston (71) is slidably arranged in the air cavity (70), and multiple pistons (71) are fixed with the same ring (72) sleeved on the pressure head (22). The pressure head (22) is fixed with a retaining ring (73) that engages with the ring (72).

6. A control and data acquisition system based on triaxial shear test according to claim 5, characterized in that: The piston (71) is provided with a first air hole (74) at the shaft center position, and the ring (72) is provided with a plurality of second air holes (75), the first air hole (74) and the second air hole (75) are arranged and communicated in position correspondence.

7. The control and data acquisition system based on triaxial shear test of claim 1, wherein: The outer frame (1) is provided with a confining pressure system (8) and a pore pressure measurement system (9) on the side, the confining pressure system (8) is communicated with the inside of the pressure chamber (21), the base (20) is provided with a rubber sleeve (90), the rubber sleeve (90) is sequentially provided with a top cap (91), a sample (92) and a water permeable stone (93) from top to bottom, and the pore pressure measurement system (9) is connected to the bottom of the water permeable stone (93).

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