含硫充填体膨胀裂隙发育特性与单轴抗压强度的关联分析

含硫胶结充填体随着养护龄期的延长会出现膨胀开裂现象,存在明显裂隙的充填体试件再进行单轴抗压强度测试其结果十分离散,已不能有效地获得充填体力学参数.在室内进行配比试验,采用数字图像处理技术对得到的充填体表面裂隙图像进行二值化、去噪等预处理,而后计算其分形维数并分析其演化规律,且将分形维数与单轴抗压强度关联分析.研究结果表明:充填体试件面表的裂隙存在自相似性,表面裂隙越发育,其分形维数越大;分形维数与单轴抗压强度存在负相关关系,分形维数越小,其单轴抗压强度越高;分形维数可判别含硫充填体试件的完整性,当充填体表面裂隙的分形维数小于某阈值时,强度试验的结果更为可靠.

Association analysis of expansion crack development characteristics and uniaxial compressive strength property of sulphide-containing backfill

The cemented backfill body with sulphide-containing tailings exhibits a swelling phenomenon with an extension of curing age. The test results from the uniaxial compressive strength test of the backfill specimen with an obvious fracture are very discrete, and the mechanical parameters of the filling body will not be obtained effectively. The fractured surface image of the backfill were binarized by the digital image processing technology. Additionally, its fractal dimension was calculated and analyzed. Then, the relationship be-tween fractal dimension and uniaxial compressive strength was established. The results indicate that the cracks on the surface of the backfill specimen exhibite self-similarity. The fractal dimension increases with the development of surface cracks. There is a negative correlation between fractal dimension and uniaxial compressive strength for the sulphide-containing backfill. It is of practical signifi-cance to determine the research value of the compression test using the fractal dimension. When the fractal dimension of the surface cracks is less than a certain threshold, the results of the specimen strength tests would be reliable.