【摘要】 本文利用自制的混凝土三轴试验系统,对国内尚未研究的轻骨料混凝土在常规三轴及真三轴受压状态下的强度特性进行了试验研究;分析了中间应力对强度的影响;在与普通混凝土三轴受压状态下的特性进行比较中,发现它与普通混凝土的显著差别除极限强度低外,在三向高压应力比下具有明显的平台流塑特性。据此,提出轻骨料混凝土在八面体应力空间下表述的强度准则。该准则的特点是考虑了平台流塑应力的影响;考虑了罗德角影响的偏平面上的强度包络线方程,形式简单,且能充分满足边界条件,与试验结果符合较好。本文的工作为充分利用轻骨料混凝土在三轴应力状态下的强度,提供了试验及理论依据。更多还原

【Abstract】 The strength of lightweight concrete under triaxial compressive stress is studied experimentally by using concrete triaxial apparatus designed by the authors.The influence of the intermediate principal stress on the mu-Itiaxial strength of the lightweight concrete is discussed. As compared with normal conrete, it is found that the multiaxial compressive strength of lightweight concrete is small, and a plastic flow plateau obviously exists in stress-strain curve under high triaxial compressive stress. Based on the experiment data, a failure criterion expressed in terms of octahedral stresses is proposed.It takes account of the influence of the plastic flow plateau in the stress-strain curve on the strength of the lightweight concrete, therefore, there are two intersections between the failure surface and the hydrostatnc axis, i.e.the failure surface is a closed surface. This criterion, though simple in expression, can also take account of the influence of Ro-der angle on the strength of the lightweight concrete in the deviatoric plane, and satisfies the boundary condition. The calculation .and experiment results of strength of lightweight concrete are well agreeable.更多还原