A fully hydraulic non-servo rock creep test device and method

Abstract

The invention belongs to the field of the rock creep test, and specifically relates to a full-hydraulic non-servo rock creep test device and method. The technical scheme is as follows: the full-hydraulic non-servo rock creep test device comprises a disc type sealing single-action loading hydraulic cylinder and a hydraulic pressure-stabilizing system. Through the full-hydraulic non-servo rock creeptest device and method provided by the invention, a test machine is simple in structure, high in load control precision, the load control precision can satisfy the requirement under the test environment of large temperature difference between day and night, the purchasing cost is low, the use maintenance cost is low, and the environment pollution is avoided.

Description

technical field [0001] The invention belongs to the field of rock creep tests, and in particular relates to a fully hydraulic non-servo rock creep test device and method. Background technique [0002] Rock creep refers to the phenomenon that the deformation of rock continues to increase with the passage of time under the condition of constant rock stress. For rock engineering with a long service life, rock creep characteristics have an important impact on the stability of rock mass engineering structures. Indoor creep test is one of the main means to obtain and evaluate rock creep characteristics. Rock creep testing machine is the basic equipment for indoor rock creep testing. The basic requirement for creep testing machine is to provide constant load. [0003] The test of rock creep properties usually takes 15-20 days for a rock sample. For other mechanical properties of the rock, it only takes 15-30 minutes for each rock sample. Therefore, the test of rock creep propert...

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Problems solved by technology

[0017] 1) On the one hand, the loading cylinder is used to generate the load required for the rock creep test. On the other hand, due to the existence of frictional resistance, the load of the testing machine cannot be directly obtained from the pressure of the loading cylinder, which can only be measured by the load sensor The force value (load) is used as a feedback signal to control the pressure of the hydraulic cylinder (when the load is constant, the pressure of the hydraulic cylinder is variable), so the control technology is complicated;

[0018] 2) The key control element of the hydraulic system, the electro-hydraulic servo (or proportional) valve is a precision hydraulic component, which is expensive, has high requirements for use and maintenance, and is easily damaged;

The requirements for the working temperature of the working fluid are also very high, and the circulation of the hydraulic oil generates a lot of heat, so a larger oil tank and a better cooling device are used to control the oil temperature, which makes the hydraulic system of the testing machine complicated;

[0020] 4) Due to the above reasons, the purchase cost of rock creep testing machine based on electro-hydraulic servo control is high;

[0021] 5) Due to the use of hydraulic oil as the working medium, it pollutes the laboratory environment a lot

Due to the continuous operation of the oil source, the energy consumption is large, so the maintenance cost is high;

[0022] 6) In a non-isothermal environment, high-precision constant load control is difficult

Therefore, the difference between the actual magnification and the theoretical magnification using this type of technology is relatively large;

[0034] 2. Since the frictional resistance is not a constant value, the load cannot be calculated by multiplying the weight (gravity) of the heavy object by the theoretical magnification, and the rock creep testing machine using this type of technology cannot accurately set the experimental conditions in advance (for creep tests, the rock sample stress);

[0035] 3. The creep testing machine combined with multi-stage lever and loading hydraulic cylinder also has friction resistance between the piston and the seal, so it is impossible to directly calculate the rock sample stress according to the pressure of the loading hydraulic cylinder;

[0036] 4. Because there is no control on the load at all, it is greatly affected by the test environment, and the test accuracy is difficult to meet the requirements

[0037] 5. It is difficult to adapt to rock creep tests under high stress and large load conditions (such as loads up to several hundred tons)

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