多轴应力下混凝土的强度和破坏准则研究

INVESTIGATION OF STRENGTH AND FAILURE CRITERION OF CONCRETE UNDER MULTI-AXIAL STRESSES

本文总结了作者完成的混凝土二轴和三轴拉压强度试验的全部数据,其中包括三轴拉/压/压和拉/拉/压试件45个;分析了不同应力状态下混凝土强度的变化规律;归纳了五种典型破坏形态及其划分条件。据此,本文建议了幂函数形式的五参数破坏准则,以及相应的参数确定原则和参数值。本准则给出的混凝土破坏面形状,或拉压子午线和偏平面包络线的形状符合试验破坏面的几何特性。与本试验和国内外试验数据对比都表明,本准则的混凝土多轴强度理论值具有较高的准确度。本文还将现有混凝土破坏准则归纳为三种基本形式,并通过计算进行对比分析,作出适当评价。

Cubic concrete specimens were tested under bi-and tri-axial stresses states by the authers, in which 45 pieces of them were tested under tensile-compressive-compressive or tensile-tensile-compressive stresses. All the experimental data are summarized in this paper. The regularity of the varying strength of concrete under different stress conditions are analyzed, Five kinds of typical failure patterns are concluded with their stress-ratio ranges presented.A fiveparameter model of failure criterion is suggested and the values of the parameters are given.The shape of spatial failure surface, or the shapes of tensile and compressive meridians and the envelopes on deviated planes, given by the suggested criterion fit well with the experimental failure surface in geometry characteristics. Comparing with the experimental data from both the authors and other researcheres, the theoritical values of multi-axial strength of concrete obtained from the suggested criterion show sufficient accuracy.Besides, the available f ilure criteria for concrete given by different researchers are induced into three basic formulae, and are compared and evaluated through numerous calculations.