CN106248482A - A kind of Triaxial tester being applicable to soft rock and method - Google Patents

Abstract

The invention relates to a triaxial test device and method suitable for weak rocks. The device part mainly includes a base, and a bracket is fixedly connected to the base; the top of the bracket is fixedly connected to the Z-axis stress loading mechanism; the lower part of the bracket supports the X-axis stress loading mechanism and the Y-axis stress loading mechanism; the X-axis stress loading mechanism is located on the Y-axis Above the stress loading mechanism, there is a positioning block on the X-axis stress loading mechanism; wherein, both the X-axis stress loading mechanism and the Y-axis stress loading mechanism have a pressure plate driven by a screw pair. This device adopts a new structure design, and adopts a combination of a single-axis cylinder and another two-axis non-cylinder loading mechanism for three-axis pressurization, so that it can control the loading force very accurately, so as to realize the research on the mechanical properties of weak rocks .

Description

A triaxial test device and method suitable for weak rock

technical field

The invention relates to the relevant technical fields of mechanical engineering and geotechnical engineering, in particular to a triaxial test device and method suitable for weak rocks.

Background technique

With the development and utilization of underground space, there are more and more excavations of deep-buried ultra-long-span tunnels, large-scale underground powerhouses in hydropower projects, and steep and high rock artificial slopes. The failure mechanism of rock mass under three-dimensional stress state Research has become a hot spot in the field of rock mechanics and engineering.

In the indoor experiment, three axial pressures were applied to the rock specimen by the rock triaxial testing machine, and the mechanical behavior of the rock was observed and recorded. Conventional rock triaxial testing machines are expensive and costly, and the related equipment occupies a large area and requires a large laboratory. At the same time, the testing machine is heavy and difficult to move.

The rock triaxial testing machine can obtain the mechanical properties of most rock materials through triaxial loading, and in the pressure test of rocks and rocks with weak and broken materials, due to the weakness of some rock materials, the rocks and rocks will It will be crushed, so the conventional three-axis oil cylinder pressurized testing machine is not easy to collect the mechanical parameters of weak and broken rock specimens. The indoor test equipment limits the sample size, so it is necessary to solve the problem of triaxial test equipment that can carry out different sample sizes and reduce the current sample size span.

To sum up, how to design a device suitable for triaxial loading tests on weak rocks is an urgent problem to be solved by those skilled in the art.

Contents of the invention

The object of the present invention is to provide a kind of triaxial test device suitable for weak rocks in order to overcome the deficiencies of the above-mentioned prior art. This device adopts a new structure design, and adopts a combination of a single-axis cylinder and another two-axis non-cylinder loading mechanism for three-axis pressurization, so that it can control the loading force very accurately, so as to realize the research on the mechanical properties of weak rocks .

In order to achieve the above object, the present invention adopts the following technical solutions:

A triaxial test device suitable for weak rocks, including:

a base, a support is fixedly connected to the base;

The top of the bracket is fixedly connected with the Z-axis stress loading mechanism;

The lower part of the bracket supports the X-axis stress loading mechanism and the Y-axis stress loading mechanism;

The X-axis stress loading mechanism is located above the Y-axis stress loading mechanism, and the X-axis stress loading mechanism has a positioning block;

Wherein, both the X-axis stress loading mechanism and the Y-axis stress loading mechanism have a pressure plate driven by a screw pair. The pressure plate is driven by the screw pair to move, so that the pressure plate can exert appropriate pressure on the weak rock to facilitate subsequent research.

Preferably, the Y-axis stress loading mechanism is a vertically arranged oil cylinder.

Preferably, the X-axis stress loading mechanism includes a shell connected to the bracket;

There is a drive motor inside the shell, and the drive motor drives the two pressure plates to move relative or oppositely through the screw pair;

The pressure plate is guided by the slide rail pair;

Wherein, the lead screw in the lead screw pair is a positive and negative lead screw. Through the movement of the positive and negative lead screws, the synchronous movement of the two pressure plates on the same lead screw can be realized.

Preferably, the Y-axis stress loading mechanism includes a shell connected to the bracket;

There is a drive motor inside the shell, and the drive motor drives the two pressure plates to move relative or oppositely through the screw pair;

The pressure plate is guided by the slide rail pair;

Wherein, the lead screw in the lead screw pair is a positive and negative lead screw.

Preferably, the driving motor is a servo motor or a stepping motor.

Preferably, the X-axis stress loading mechanism has a sample seat, and a positioning ball is provided in the sample seat;

The sample seat and the positioning ball form a universal ball matching structure;

One end of the support rod is fixedly connected with the positioning ball, and the other end of the support rod is fixedly connected with the positioning block. This structure allows the sample to move freely until the center is found when it receives an external force after it is placed on the positioning block.

Preferably, the orthographic projection of the positioning block is located within the orthographic projection of the sample holder.

Preferably, the piston rod of the oil cylinder is provided with a pressure sensor, and the pressure sensor is connected with the information collection system.

Preferably, a pressure sensor is arranged on the pressure plate, and the pressure sensor is connected with an information collection system.

While providing the above-mentioned structural scheme, the present invention also provides a method for using the above-mentioned device for testing, which mainly includes the following steps:

A. Place the sample on the positioning block;

B. Let the Z-axis stress loading mechanism contact the sample to level the sample;

C. Make the X-axis and Y-axis stress loading mechanism move synchronously until the pressure plate fits the sample;

D. Let the Z-axis, X-axis and Y-axis stress loading mechanism pressurize the sample, and record the displacement of the pressure plate and the stress change of the sample at the same time.

The beneficial effects of the present invention are:

(1) The information collection system can automatically collect the displacement and stress information of rock specimens.

(2) The test device is suitable for multi-scale rock samples, and realizes the loading, unloading and rheological experiments of rock samples under different sizes.

(3) The lateral stress load is pressurized by the lead screw to ensure the synchronization of pressurization. At the same time, the low stress provided by the control of the lead screw mechanism can be used for loading, unloading and rheological experiments of weak and broken rock specimens.

(4) The equipment has simple structure, low cost and convenient use.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the matching figure of sample holder among the present invention;

Fig. 3 is a schematic structural view of the X-axis and Y-axis stress loading mechanism in the present invention;

Fig. 4 is a schematic circuit diagram of the present invention;

Fig. 5 is the free state schematic diagram of sample holder in the present invention;

In the figure: 1. Bracket, 2. Z-axis stress loading mechanism, 3. Y-axis stress loading mechanism, 4. X-axis stress loading mechanism, 5. Connecting plate, 6. Positioning block, 7. Pressure plate, 8. Shell . Two sliders, 18, base plate, 19, drive motor, 20, pressure sensor, 21, information collection system, 22, base.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings.

Embodiment: a kind of triaxial test device suitable for weak rock, its structure is as shown in Figure 1-3, comprises:

The base 22 is fixedly connected with a support 1; the support 1 is a hollow structure, and the support 1 has a side plate and a cross-shaped top plate fixedly connected with the side plate, and the middle part of the lower surface of the cross-shaped top plate and the Z-axis stress loading mechanism 2 fixed connections.

The side plate is divided into upper and lower parts, the lower part is fixedly connected with the base 22, the upper part is fixedly connected with the cross-shaped top plate, and the upper part and the lower part are fixedly connected with the stress loading mechanism.

The stress loading mechanism includes two, namely an X-axis stress loading mechanism 4 and a Y-axis stress loading mechanism 3 , and the X-axis stress loading mechanism 4 is located above the Y-axis stress loading mechanism 3 .

The structures of the two stress loading mechanisms are the same, and they are perpendicular to each other. Any stress loading mechanism includes a shell 8, and the inside of the shell 8 has a base plate 18. Two bearing blocks 13 are installed on the base plate 18, and a positive and negative lead screw 16 is installed between the two bearing blocks 13. The positive and negative lead screw 16 Driven by a drive motor 19, the two sides of the positive and negative lead screw 16 are slide rails 15.

On the positive and negative lead screw 16, the positive and negative wires are respectively equipped with a first slider 14 and a second slider 17, and the inside of the two sliders is equipped with a nut that is compatible with the normal or reverse wire. , both sliders are guided by slide rail 15. Driven by the driving motor 19, the two slide blocks can move relatively close to each other or move away from each other.

At the same time, each slider is connected with a connecting plate 5 , and the top of the connecting plate 5 is fixedly connected with the pressure plate 7 . The difference is that the connecting plate 5 on the Y-axis stress loading mechanism 3 is longer, so that the upper and lower surfaces of the four pressure plates 7 are all on the same level.

The structure, size and material of the four pressure plates 7 are the same, so that the uniformity of the stress applied to the sample can be further improved. At the same time, a pressure sensor 20 is installed inside each pressure plate 7 so as to transmit the pressure signal received by the sample 9 to the information collection system 21 .

As an option, the Z-axis stress loading mechanism 2 may be an oil cylinder, or other mechanisms with a planar loading surface, and at the same time, a pressure sensor 20 also needs to be installed in the Z-axis stress loading mechanism 2 .

From the viewpoint of being convenient to control, the drive motor 19 can be selected as a stepping motor or a servo motor, so that the test accuracy can be further improved, and the stroke of the pressing plate 7 can be easily controlled, so that the displacement of the pressing plate 7 can be changed, The mechanical properties of sample 9 were comprehensively studied on the stress change and crushing condition of sample 9.

For samples of different materials, the flatness of the surface is not the same. In order to facilitate the centering of the sample, a sample seat 11 is fixedly connected to the X-axis stress loading mechanism 4 in this device. The sample seat 11 has a spherical groove, and a positioning ball 12 is installed in the groove. 12 and the sample holder 11 form a universal ball structure. At the same time, the positioning ball 12 is connected with the support rod 10, and the support rod 10 is fixedly connected with the positioning block 6, and the positioning block 6 is used for placing the sample.

After adopting the above-mentioned positioning structure, the sample 9 can be placed on the positioning block 6, and the positioning block 6 can rotate freely, so that the sample 9 can be automatically centered during the pressure loading process, and the accuracy of the sample precision can be improved. sex.

Referring to FIG. 5 , as a better option, the orthographic projection of the positioning block 6 is located within the orthographic projection of the sample holder 11 . In this way, the sample can be deflected to a certain extent without being subjected to external force, but it will not slide off from the positioning block 6 under the action of gravity.

It is worth noting that during the test, it is necessary to ensure that the orthographic projection of the sample is larger than the orthographic projection of the sample holder 11, so that it can be ensured that the pressure plate 7 can be pressed on the sample 9 instead of being pressed. Press on the sample holder 11.

At the same time, in order to ensure the accuracy of the triaxial test, the pressure plate 7 can be used to reduce friction, and its function is to reduce the friction between the sample and the pressure plate. That is, a thin film clamping lubricant is pasted between the pressure plate 7 and the sample surface, and the lubricant can be a mixture of butter and machine oil.

The process of using this device for testing is as follows:

A. Place the sample 9 on the positioning block 6;

B. Extend the piston rod of the oil cylinder until it touches the top surface of the sample to ensure that the upper and lower surfaces of the sample are close to the level;

C. Make the driving motor 19 of the X-axis and Y-axis stress loading mechanism rotate, then the four pressure plates 7 approach the sample 9 synchronously, until the pressure plate 7 and the sample 9 are bonded;

D. Continue to make the two driving motors rotate, and make the piston rod of the oil cylinder continue to elongate, so as to realize the triaxial pressurization of the sample 9; during the pressurization process, record the displacement of the pressure plate 7 and the stress change of the sample 9.

The information collection system 21 simultaneously collects pressure values in three directions, deformation values of multiple sides and top surfaces of the sample, and records the time. And on the software interface, you can browse each data and the graphics formed between each data at any time. The pressure sensor attached to the pressure plate transmits the displacement and pressure change information of the rock to the computer in the form of electrical signals, and the corresponding software displays the pressure value of the rock in real time.

Because the driving motor can be selected as a servo motor, and the servo motor and the computer can form a closed-loop control, the displacement of the pressure plate can be calculated by the number of rotations of the servo motor, and the displacement of the pressure plate can be recorded in the software synchronously, and then The mechanical properties of weak rocks are considered comprehensively.

After adopting the above structure, this device can carry out uniaxial and biaxial tests of multi-scale rocks and concrete, medium-sized direct shear tests of rock mass and structural surfaces, and true triaxial long-term rheological and shear flow tests of medium-sized rocks. Variation test.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Parts presented in detail and partially enlarged are prior art, and will not be repeated here. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and characteristics disclosed herein.

Claims (10)

1. the Triaxial tester being applicable to soft rock, it is characterised in that including:

Base, base is fixedly connected with support；

Cradle top is fixing with Z axis stress loading mechanism to be connected；

Support bottom is by X-axis stress loading mechanism and Y-axis stress loading mechanism supports；

Described X-axis stress loading mechanism is positioned at above Y-axis stress loading mechanism, and X-axis stress loading mechanism has locating piece；

Wherein, described X-axis stress loading mechanism and Y-axis stress loading mechanism are respectively provided with the increased pressure board driven by lead screw pair.

Triaxial tester the most according to claim 1, it is characterised in that described Y-axis stress loading mechanism is for vertically to set The oil cylinder put.

Triaxial tester the most according to claim 1, it is characterised in that described X-axis stress loading mechanism includes and institute State the shell that support connects；

There is in shell driving motor, drive motor to drive two increased pressure boards relatively or reverse motions by lead screw pair；

Increased pressure board is guided by slide rail pair；

Wherein, the leading screw in described lead screw pair is positive and negative silk leading screw.

Triaxial tester the most according to claim 1, it is characterised in that described Y-axis stress loading mechanism includes and institute State the shell that support connects；

There is in shell driving motor, drive motor to drive two increased pressure boards relatively or reverse motions by lead screw pair；

Increased pressure board is guided by slide rail pair；

Wherein, the leading screw in described lead screw pair is positive and negative silk leading screw.

5. according to the Triaxial tester described in claim 3 or 4, it is characterised in that described driving motor be servomotor or Motor.

Triaxial tester the most according to claim 1, it is characterised in that in described X-axis stress loading mechanism, there is examination Sample seat, has place kick in sample holder；

Sample holder forms multi-directional ball fit structure with place kick；

One end of support bar is fixing with place kick to be connected, and the other end of support bar is fixing with locating piece to be connected.

Triaxial tester the most according to claim 6, it is characterised in that the orthographic projection of described locating piece is positioned at sample holder Orthographic projection within.

Triaxial tester the most according to claim 2, it is characterised in that be provided with pressure on the piston rod of described oil cylinder Sensor, pressure transducer is connected with information acquisition system.

Triaxial tester the most according to claim 1, it is characterised in that be provided with pressure sensing on described increased pressure board Device, pressure transducer is connected with information acquisition system.

10. the method that the Triaxial tester applied described in any one of claim 1-9 carries out testing, it is characterised in that Step is as follows:

A, sample is positioned on locating piece；

B, LingZZhou stress loading mechanism and sample contacts, leveling sample；

C, X-axis and Y-axis stress loading mechanism is made to be synchronized with the movement, until increased pressure board is fitted with sample；

D, Z axis, X-axis and Y-axis stress loading mechanism is made to pressurize to sample, record increased pressure board displacement simultaneously and sample STRESS VARIATION.