Abstract：An industrial control computer with high precision A/D board is used to control the soil static-dynamic universal triaxial and tensional shear apparatus，which was introduced from Tokyo Seiken，Inc.，Japan in 2001. The data sampling and processing systems are developed using the multithreading and direct-draw technology on the program platform of VC++6.0 language. The system can perform the collection of all the real time experimental data，including the dynamic stress，strain，and pore pressure through the whole experimental process. The experimental data can be curved on the screen，or be processed in real time，or be saved in a data file on line for processing later. In order to ensure the precision of data sampling cycle，the intramural clock frequency of the computer is used to complete the controlling of sampling frequency. The precision can be set to microsecond. The system can make data processing and data sampling entirely automatic，and succeeds in performing a series of difficult subsequent calculations，such as the calculation of the area of the hysteresis loop irregular cure and the common tangent of Mohr circle.
