轻骨料混凝土的破坏面模型

Failure Model of Lightweight Aggregate Concrete

以轻骨料混凝土和普通混凝土破坏面的不同特征为切入点,剖析了已有的混凝土破坏面模型存在的问题,指出了轻骨料混凝土破坏面应为主应力空间连续、光滑、外凸的整体闲口曲面.根据轻骨料混凝土的各向同性特征,建立了主应力空间二次函数型轻骨料混凝土的破坏面模型,并对其采用特征应力点试验数据进行了量化.量化的轻骨料混凝土椭球面破坏模型的任一剖切面(包括拉压子午线和偏平面包络线)均为椭圆曲线,避免了以往的混凝土破坏面模型的拉压子午线和偏平面包络线分别采用不同类型函数描述的问题,克服了混凝土二次抛物线型拉压子午线破坏面有尖角(不光滑、不可导)的缺陷.通过与试验数据对比分析,验证了建议的轻骨料混凝土椭球面破坏模型的精度。

Starting from different characters of failure models of lightweight aggregate concrete and normal concrete, the problems of current failure models of concrete were analyzed. It is pointed out that the fail- ure surface of lightweight aggregate concrete should be continuum, smooth and protruding curved surfaces in principal stress space. The failure model of lightweight aggregate concrete described by using quadratic functions in principal stress space was brought forward based on isotropic mechanical characters of concrete materials and was quantified with experimental results of representative stress points. The envelope curves of any cross sections of the quantified elliptical failure model, including tensile and compressive meridians and failure envelope curves in deviated plane, are shown to be elliptical curves. The problems of current failure models of concrete were solved, in which the tensile and compressive meridians and failure envelope curves in deviated plane were described by using different types of functions. The disadvantage of tensile and compressive meridians with sharp corner due to using of quadratic parabola is overcome. The precision of the suggested elliptical failure model of lightweight aggregate concrete is verified by comparing with ex- perimental data.