Development And Application Of New Piezomagnetic Overcoring In-Situ Stress Measurement System

First, we did some analysis of the traditional way of prestressing the sensors and summarized its application for occasions. Then, according to its disadvantages, we designed and manufactured a set of hydraulic equipment for prestressing the sensors.The second part introduced the design of a high precision program-controlled constant-current source for magnetic core element which uses the closed-loop control theory. The circuit uses SCM with ADC and DAC conversion modules to achieve the purpose of constant current. This design has overcome the shortcoming of old type which is consisted of discrete components that current is unstable.The next part is about a new type of confining pressure calibration chamber which is improved on some parts from the old type especially for the oblique sensors’ calibration. We designed some liquid seal equipment for the part, which has high probability of leakage, of the chamber. Also the theoretical analysis of the design is given. The new type of confining pressure calibration chamber is a all-sealed one and the entire rock core could be immersed in oil to be pressed. This make the oblique sensor could be pressed both axially and radially.At last, the software function and performance needs are analyzed, as well as the overall and detailed design of the software is dealt with. In the overall design, the frame ideas and practical steps are described. In the detailed design, the software is divided into 5 modules: data base module, data acquisition module, data analysis module, expert system module and output display module.