The specimens (cubes, d=100 mm) were statically loaded into a true triaxial apparatus. 1) The stresses in all three directions were simultaneously increased to a specified value of p. 2) The strain in Y-axis was increased monotonically while maintaining a constant minimum principle stress in Z-axis as well as a constant strain rate ratio between the X-axis and the Y-axis. Three different values of p were chosen, which were 10, 15 and 20 MPa. Three or four strain rate ratios were chosen, which were 0.25, 0.5, 0.75 and 1.0, for each value of p. According to analysis of experimental data and curves, the following conclusions were obtained. In the latter part of loading process, relationship between Z-axial strain and Y-axial strain approximates to linear, as well as the relationship between Z-axial strain and X-axial strain, but the corresponding slopes of fitting lines are different with each other under different load paths. Comparing differential equations with fitting equations of curves, when the minimum principal stress is constant, the same numerical differentiation of Z-axial strain versus X-axial strain and Z-axial strain versus Y-axial strain are calculated for different strain rate ratios, which is related to failure modes and inclination of shear bands．
LI Jing, WANG Zhe. Deformation properties of concrete under quasi plane stress sate. JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE), 2017, 51(4): 745-751.
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