Damage ratio strength criterion for various types of concrete and isotropic rock
Ding Faxing1,2 Wu Xia1 Xiang Ping1 Yu Zhiwu1,2
1. School of Civil Engineering, Central South University, Changsha 410075, China；2. Engineering Technology
Research Center for Prefabricated Construction Industrialization of Hunan Province, Central South University, Changsha 410075, China
Abstract：The existing damage ratio strength theory utilizing damage ratio variable is only applicable to concrete with the disadvantage of concave deviatoric plane loci under high hydrostatic pressure. To extend its application scope and treat with the deficiency, based on the general form of the damage ratio strength theory for concrete, a six-parameter expression of the damage ratio variable was proposed according to the characteristics of the failure envelope for concrete, recycled aggregate concrete, lightweight aggregate concrete and isotropic rock. In the proposed expression, the effects of Lode angle and hydrostatic stress on the compressive damage ratio and the effect of material type on the tensile damage ratio were taken into account. Furthermore, the values of damage ratio variable obtained by the proposed expression were verified based on the existing experimental stress-strain curves of concrete under uniaxial, biaxial and triaxial stress states and those of isotropic rock under uniaxial stress states. By comparing the predicted results to the experimental data of concrete (397 specimens), recycled aggregate concrete (130 specimens), lightweight aggregate concrete (97 specimens), “rock of type I” (179 specimens with uniaxial compressive strength fc<100 MPa) and “rock of type II” (165 specimens with fc>100 MPa), the modified criterion using six-parameter damage ratio variable can represent the corresponding characteristics of the failure envelope of aforementioned materials with high accuracy. In addition, for the materials under biaxial stress states, simplified damage ratio strength criterion curves were proposed as well.
