Through rock mechanics test, similar simulation experiment, borehole photographic observation of rock fissure, numerical simulation calculation of plastic zone distribution and deformation monitoring of rock mass during undersea mining, the fractal evolution mechanisms of rock fracture in undersea metallic deposits of Sanshandao Gold Mine were studied by fractal theory. The experimental researches on granite mechanics test in undersea deposit indicate that with the increase of load, the granite deformation energy and the fractal dimension of acoustic emission (FDAE) increase gradually. However, after reaching the peak stress of specimen, the fractal dimensions of acoustic emission (FDAEs) decrease and the granite specimen fails. Therefore, the fractal dimension evolution of rock failure can be divided into four stages, which are fissure inoculation stage, fissure growth stage, fissure expansion stage and fracture instability stage, respectively. By calculating and analyzing the damage photographs of rock specimens in Sanshandao Gold Mine, the fractal dimension of rock fissure is 1.4514, which is close to the average value of FDAE during granite destruction, i.e., 1.4693. Similar simulation experiments of undersea mining show that with the excavation proceeding, the FDAE in rock stratum increases gradually, and when the thickness of the isolation roof is less than 40 m, the FDAE begins to decrease, and meanwhile the sign of water inrush emerges. The numerical simulation researches on the plastic zone distribution of undersea mining in Sanshandao Gold Mine indicate that the fractal dimension of plastic zone (FDPZ) where the failure characteristics occur is 1.4598, close to the result of similar simulation experiment of 1.4364, which shows the sign of water inrush. Meanwhile, the thickness of the isolation roof for undersea mining should be more than 40 m, which is consistent with the results of similar simulation experiment. In Sanshandao Gold Mine, the rock fissures in undersea mining were observed by borehole photography and the rock mass deformation was monitored by multi-point displacement meters, and at the same time the fractal dimensions of strata borehole fissure distribution and energy release ratio (ERR) of rock mass were calculated by fractal principle, which are 1.2328 and 1.2685, respectively. The results demonstrate that rock deformation and fissure propagation are both in the second stage of fissure growth, and have not reached the fourth stage of fracture instability. Therefore, the conclusion can be obtained that the undersea mining in Sanshandao Gold Mine is safe at present.

通过岩石力学试验，相似的模拟实验，井下裂隙的照相照相观察，海底采矿过程塑性区分布的数值模拟计算和岩体变形监测，研究了三山岛金矿海底金属矿床岩石破裂的分形演化机理。分形理论。对海底沉积物进行花岗岩力学试验的实验研究表明，随着载荷的增加，花岗岩变形能和声发射分形维数（FDAE）逐渐增大。但是，在达到样品的峰值应力后，声发射（FDAE）的分形维数减小，花岗岩样品失效。因此，岩石破坏的分形维数演化可以分为四个阶段，分别为孕育期，孕育期，扩张期和骨折失稳期。通过对三山岛金矿岩石标本的破坏照片进行计算和分析，岩石裂缝的分形维数为1.4514，接近花岗岩破坏过程中FDAE的平均值1.4693。类似的海底采矿模拟实验表明，随着开挖的进行，岩层中的FDAE逐渐增加，当隔离顶板的厚度小于40 m时，FDAE开始减小，同时出现了涌水迹象。对三山岛金矿海底开采塑性区分布的数值模拟研究表明，破坏特征发生的塑性区的分形维数为1.4598，接近于1.4364的类似模拟实验的结果，表明出现了突水迹象。同时，海底采矿隔离顶板的厚度应大于40 m，这与类似的模拟实验结果是一致的。在三山岛金矿，通过钻孔照相观察海底采矿中的岩石裂隙，并通过多点位移计监测岩体变形，同时，地层钻孔裂隙的分形维数和能量释放率（ERR）分形原理计算岩体质量，分别为1.2328和1.2685。结果表明，岩石变形和裂隙扩展均处于裂隙扩展的第二阶段，尚未达到断裂失稳的第四阶段。因此，