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根据国际岩石力学学会建议采用的岩石断裂韧度测定方法,用短棒试件在Instron 1342型电液伺服控制材料试验机上测定了无烟煤准静态I型断裂韧度,其断裂韧度值在位移速率较低时提高较大,但随位移速率的提高有逐渐趋于稳定的趋势。从载荷-COD曲线图中分析了无烟煤断裂时,载荷出现跳动的原因,根据载荷跳动情况可以确定三角形韧带开始起裂时间。根据计算结果得出:试件加工几何上的误差对无烟煤断裂韧度值影响不大,造成的误差最大只有2.4%;但对弹性模量值的影响较大,造成最大的误差达到13.3%,同时用图解法得到了无烟煤的非线性度大于0.4。
According to the method of determination of rock fracture toughness recommended by the International Society for Rock Mechanics, the quasi-static type I fracture toughness of anthracite was measured with a short rod specimen on an Instron Model 1342 electro-hydraulic servo controlled material testing machine. The fracture toughness value of the rock- It is higher when lower, but tends to be steady with the increase of displacement rate. From the load-COD curve, the cause of the beating of the load during the rupture of the anthracite coal is analyzed. The onset time of the triangular ligament can be determined according to the load-beating condition. According to the calculation results, it is concluded that the geometrical error of the specimen has little effect on the fracture toughness of anthracite, and the maximum error is only 2.4%. However, the influence on the elastic modulus is larger, resulting in the maximum error of 13.3% At the same time, the non-linearity of anthracite coal obtained by graphic method is more than 0.4.