三轴拉压应力状态下沥青混合料的破坏准则

Failure criterion of asphalt mixture in triaxial tension and compression state

为了解拉压组合复杂应力状态下沥青混合料的强度特性,在自主研发的三轴试验设备上,通过单轴拉、单轴压、平面拉压/轴向压缩和平面拉压/轴向拉伸应力状态下共74个试件的试验,系统研究拉应力和压应力共同作用下AC-13C沥青混合料的三轴强度特性和破坏特征。基于八面体强度理论,建立多轴拉压条件下AC-13C沥青混合料的线性破坏准则。研究结果表明:试件分别表现为拉应变和拉应力破坏特征;三轴拉强度和压强度均低于单轴拉伸强度和单轴压缩强度,按现行的最大拉应力理论进行沥青路面结构设计偏于危险;线性破坏准则考虑3个主应力对路面的协同破坏作用,可较好地描述沥青路面材料的三轴强度规律,并且形式简单,便于工程应用。

In order to study strength properties of asphalt mixture in multiaxial tension and compression complex stress state, uniaxial tension and compression strength tests, as well as plane tension and compression/axial compression, plane tension and compression/axial tension tests were carried out by self-developed triaxial test machine. The triaxial strength properties and failure characteristics of AC-13 C asphalt mixture were studied under the combined action of compression and tension stress through the tests of 74 specimens. A linear failure criterion of AC-13 C asphalt mixture under multiaxial tension and compression stress condition was established by octahedron stress theory. The results show that the specimens have characteristics of tensile strain and tensile stress failure. Triaxial tension and compression strength is less than uniaxial tension strength and uniaxial compression strength. So, the maximum tensile stress theory which is used as failure criterion in asphalt pavement design in China may be somewhat unsafe. The failure criterion considers the synergistic damage effect among each principal stress, and it can be adequately used to describe the triaxial strength law of asphalt pavement material. It has simple expression form and is convenient for engineering application.