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Abstract Currently，the dimensions of rock samples used in true triaxial experiment are either too large or too small，the span of dimension is large and magnitudes of stress levels are different，which brings inconvenience to the study of size effect of strength for rock mass in triaxial stressed conditions as well as its deformation and strength characteristics under complex stress path. To cope with this issue，the true triaxial experiment system for middle sized rock samples，named LWZ–10000，is developed. The design concept，composition feature，technical indexes and main function are introduced in detail. The system has such noticeable features as follows：(1) Automatic servo control and data collection during whole process of deformation failure with high precision and stable performance. (2) The dimension of rock samples is between that used in laboratory experiment and in field experiment. Moreover，the dimension can be altered in a certain range. (3) The magnitudes of lateral and axial loads can be large and the magnitudes are controlled independently in three loading directions. (4) Ultrasonic and acoustic emission experiments can be conducted simultaneously. A lot of true triaxial experiments for Jinping marble samples under different stress paths are carried out by the developed system. The whole process stress-strain curves and the relationships with wave speeds in true triaxial experiments under loading and unloading paths are analyzed. Combining with the true triaxial experiment results of different sized marbles under unloading path，the size effect of strength parameters for marble under unloading path is preliminarily studied. The successful development of this system provides new approach to studying the deformation and strength characteristics of deep rock mass considering multidirectional stress state and different stress paths.
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Received: 20 April 2012
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2012, Vol. 31 
