Hydraulic loading system of triaxial device for soil test

Abstract

The invention discloses a hydraulic loading system of a geotechnical triaxial instrument, which comprises a loading oil cylinder, a hydraulic oil pump and a driving motor of the hydraulic oil pump. The hydraulic circuit is connected with the upper chamber and the lower chamber of the loading oil cylinder. One end of the check valve is connected to the upper chamber of the hydraulic circuit, the other end is connected between the sequence valve and the overflow valve, and connected to the auxiliary oil tank; the single-chip microcomputer is connected to the driving motor of the hydraulic oil pump through the drive amplifier; A pressure sensor is connected, and the pressure sensor is connected to the single-chip microcomputer through a pressure sensing amplifier; a displacement sensor is connected to the piston rod of the loading cylinder, and the displacement sensor is connected to the single-chip microcomputer through a displacement sensing amplifier. The present invention has the following beneficial effects. First, the throttling speed regulation is changed to volumetric speed regulation, which can conveniently control the acceleration speed of the loading oil cylinder, greatly simplifies the hydraulic system, does not waste the power of the motor, and does not raise the oil temperature quickly. High, energy saving is very obvious; second, the open hydraulic transmission is changed to a closed hydraulic transmission, which makes the oil source very simple, uses very little oil, and greatly reduces the volume; third, because it does not use expensive servo valves, the oil The requirements for filtration are greatly reduced, and the cost is greatly reduced; the fourth is that the position, strain and stress control system can be conveniently formed.

Description

Technical field [0001] The invention relates to an instrument for geotechnical testing. Background technique [0002] "Geotechnical triaxial instrument" is an indispensable testing equipment for the analysis and research of soil mechanical properties and deformation in the field of civil engineering, and it is also the most basic equipment for related laboratories. It is mainly used for the detection, analysis and recording of data related to soil stress, strain and volume change, and provides original and necessary data for related engineering design. The hydraulic loading system of the currently used hydraulic geotechnical triaxial instrument belongs to open throttle speed regulation, and its basic form is composed of an AC asynchronous motor, an oil pump, an overflow valve and other components, and an oil source that provides a certain pressure and flow , And then enter the loading cylinder through the servo valve (or proportional valve), and (single rod piston type) change th...

AI Technical Summary

Problems solved by technology

The hydraulic loading system of the hydraulic geotechnical triaxial instrument currently used belongs to the open throttling speed regulation, and its basic form is composed of an AC asynchronous motor, an oil pump, a relief valve and other components to form an oil source that provides a certain pressure and flow. , and then enter the loading cylinder through the servo valve (or proportional valve), (single-rod piston type) change the magnitude of the input current of the servo valve (or proportional valve), which can control the speed of the loading cylinder, but due to the "geotechnical triaxial instrument" The loading speed is very small, V mim =0.0024mm / mim, because the speed is too low and the flow rate is very small, most of the oil is discharged from the relief valve, which not only wastes power, but also makes the oil temperature of the hydraulic system rise rapidly, so the oil cooling system is essential

Therefore, some designers have changed this to bypass throttling, which has improved the temperature rise, but the stability of loading and speed have been destroyed.

Moreover, due to the use of servo valves (or proportional valves), the requirements for the filtration accuracy of the oil are very high, and the complicated filtration system increases the cost invisibly. On the other hand, due to the high cost of the servo valve (or proportional valve), the sales The price ranges from thousands of yuan to tens of thousands of yuan, which makes this system costly, complex in structure, large in size, and poor in low-speed performance

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