岩石与混凝土界面断裂特性的试验研究

Experimental Study on Fracture Properties of Rock and Concrete Interface

通过试验研究了界面断裂韧度与复合模态角的关系。利用岩石与混凝土复合梁试件进行了四点剪切试验,其优点是采用单一试件形式及加载方式即可实现较大范围模态比的界面断裂韧度测试。试验结果表明,试件发生界面断裂时,随着模态角ψ的增加,模态1(Kun1c)和模态2(Kun2c)的临界应力强度因子分别减小和增大。模态1的应力强度因子在小模态角情况下几乎不受其变动的影响,实际问题中可假定为一常数。临界应变能释放率Gun c随着模态角的增加而增加。通过非线性数据拟合,给出了Gun c与模态角的关系。

The dependency of interfacial fracture behavior and complex mode angle is studied here through tests. The four-point-shear tests on concrete/rock composite beams are performed, allowing the complex mode angle to vary within a wide range. It is found that with the increase of the complex mode angleφ, the critical stress intensity factors of mode 1 （K^un_1C） and mode 2 （K^un_2C） would be decreased and increased respectively. The critical stress intensity factors of mode 1 are hardly influenced by low mode angle, and a constant value can be assumed and applied to special problems. The critical strain energy＇ s release rate for unstable crack propagation （G^un_C） increases as the complex mode angle increases. For the investigated materials, the quantitative expressions for critical strain energy＇ s release rate are obtained through nonlinear data-fitting.