深水基槽开挖中水下重锤破岩规律研究

Study on the underwater rock breaking characteristics by heavy hammer in the process of base slot excavation

基于深中通道水下沉管隧道基槽凿岩工程,采用数值模拟方法研究了重锤凿岩棒受力状态和凿岩棒下落过程的速度变化规律以及凿岩棒凿击岩石的损伤发育特征,分析了不同水深、不同冲击速度、不同凿击次数对岩石破坏和损伤的影响规律。结果表明:凿岩棒下落过程中速度先线性增加然后增加幅度逐渐降低,最终趋于稳定的收尾速度;在凿岩棒凿击岩石过程中,其速度不断下降并伴随着岩石损伤的累积;水深与岩石的损伤呈负相关关系,而冲击速度和凿击次数与岩石的损伤呈正相关关系。

The stress state and the variation law of velocity in the falling process of rock breaking hammer are studied according to the immersed tunnel foundation trench in the Shenzhen-Zhongshan passage project. The FEM method is used to simulate the process of rock drilling, study the damage development characteristics of rock and analyze the influence law of water depth, impact velocity and drilling times on the rock failure and damage development. The results show that during the falling process, the velocity of rock breaking hammer increases linearly first, then decreases gradually, and finally tends to a stable ending velocity. The speed of the hammer decreases and the damage accumulates in the process of drilling. In addition, the water depth is negatively correlated with the rock damage, while the impact velocity and impact times are positively correlated with the rock damage.