碾压混凝土拱坝诱导缝开裂试验研究

通过多组由深埋椭圆裂缝、深埋矩形裂缝和穿透裂缝3种型式形成不同削弱度的碾压混凝土试件轴拉试验，研究了试件的应力强度因子，分析了不同裂缝的应力强度因子计算公式。由于试件的断裂韧度与裂缝形式无关，假设深埋矩形预留缝试件的应力强度因子可以由深埋椭圆预留缝或穿透预留缝试件的应力强度因子通过修正求得，建立了矩形预留缝试件应力强度因子的近似解析表达式。考虑了尺寸效应后，求得碾压混凝土材料的断裂韧度。根据碾压混凝土拱坝诱导缝的构造特点，并考虑了相邻缝的影响计算出诱导缝开裂的等效强度。这一结果应用于沙牌碾压混凝土拱坝开裂计算的三维非线性应力场仿真计算中。

Experimental study on cracking of induced joints in RCC arch dam

The stress intensity factors of RCC specimens with three types of crack having different weakening ratios are studied by means of axial tension test. The formulas for calculating stress intensity factors are established. Because the toughness of crack is independent of the form of crack, and assuming that the stress intensity factors of deep buried rectangular cracks may be d educed from the factors of deep buried elliptical cracks or penetrated cracks, the approximate expressions of the stress intensity factors of deep buried rectangular cracks are established. After the correction of dimension effect, the toughness of RCC material can be obtained. In consideration of the structure characteristics of induced joints and the influence of adjacent cracks, the equivalent strength of crack for induced joints can be calculated. This result is used to simulate the 3-D nonlinear stress field in the RCC arch dam of Shapai Hydro Project