基于重整化群方法的红层软岩损伤破坏逾渗阈值研究

逾渗现象广泛存在于大自然中,当物体中起决定性作用的关键变量变化至某一阈值时,其状态发生突变,此时关键变量的临界值称为逾渗阈值。岩石在水的作用下的损伤破坏过程中存在着逾渗现象,可通过重整化群的方法来研究。本文针对华南地区广泛分布的红层软岩,探讨了其在损伤过程中的逾渗现象与破坏的本质关联。通过对典型红层软岩的微观结构分析,概化出红层软岩的骨架构件和胶结物构件,建立红层软岩的重整化群模型的基本单元,将基本单元进行组合,建立出红层软岩的重整化群模型。根据重整化变换规则,推导计算出其逾渗阈值。研究表明:当红层软岩在荷载条件下的破坏临近逾渗阈值时,其内部结构发生大量破坏,软岩内部从无序损伤突变为有序损伤,继之损伤破坏加剧,由稳定破坏向非稳定破坏突变,最终导致其失稳破坏。研究对揭示红层软岩损伤破坏机理具有重要意义。

STUDY ON PERCOLATION THRESHOLD OF RED-LAYER SOFT ROCK FAILURE PROCESS BASED ON THE RENORMALIZATION GROUP METHOD

The percolation phenomena, which are that with some kind of critical factor changing, the original properties of the object will sudden change, widely exist in nature. And when the changing is happening, the value of the critical factor is the percolation threshold. The percolation phenomena also exist in the process of rock damaging and failure and the percolation threshold can be studied by renormalization group approach. Assumed that the failure of red-layer soft rock cased by the failure of cement in structure. And according to the microscopic structure of silty mudstone, one kind of red-layer soft rock, can build the renormalization group model of red-layer soft rock. In order to facilitate the calculation, the rules of renormalization transformation set simply. Then the percolation threshold of red-layer soft rock failure under loading condition can be calculated by the renormalization group approach. When the damage extent of red-layer soft rock failure under loading condition reached the percolation threshold, the inner structure will damage in large-scale and the strength will drop rapidly. The random damage of red-layer soft rock change into ordered damage, the velocity of damage becomes faster.