三轴受压状态下岩石试块变形破坏过程中孔隙水压的变化特征及其临界破裂前兆

Pore water pressure change-related characteristic and its critical rupture precursor of rock under triaxial compression

为讨论饱水岩石中孔隙水压与损伤变形过程的关联性,探究岩石破坏的孔隙水压前兆特征信息,采用三轴压缩试验、渗流实验相结合的方法,分析了在不同孔隙水压和不同围压条件下饱水岩石变形破坏过程中损伤扩展与孔隙水压变化的内在联系.研究表明:(1)开放饱和岩石单元体中,岩石在受荷破坏全过程中的初始压密、弹性压缩、塑性变形和破坏失稳阶段,孔隙水压呈现增高、稳定、逐渐减小和锐减变化;(2)岩石破坏的孔隙水压前兆特征明显,在主破裂前夕,内部损伤加剧,裂隙贯通,孔隙水压将失去稳定状态,孔隙水压由稳态锐减可作为岩石破裂的前兆信息;(3)在应力变化大、高孔隙水压以及高围压条件下,孔隙水压对损伤发展更为敏感,响应也更明显,孔隙水压与损伤发展相互影响,互为关联,损伤扩展造成孔隙水压降低,孔隙水压降低又促进损伤发展;(4)可以尝试在深部开采工程中监测岩体内部孔隙水压的变化来预测岩体失稳的突发性灾害.

The change of pore water pressure in saturated rocks was closely associated with its damage deformation. In order to study the precursory characteristics of pore water pressure before the damage of saturated rock, the triaxial compression test and seep age test were used in the paper. The research show that ： 1 ） During the process of damage in open saturated rock unit, namely phases of the initial compression, elastic compression, plastic deformation and destruction, the pore water pressure would increase, stay sta ble, gradually decrease, and sharply decrease respectively ; 2） Internal damage intensified, cracks connected with the pore water pres sure lost steady state could be used as a precursor to rock failure information ; 3 ） The pore water pressure to the development of damage was more sensitive and the response was more obvious in the condition of large pressure change, high pore pressure and high confining pressure ; Pore pressure and damage development were interrelated, that the development of damage caused the decrease of pore pres sure. At the same time the decrease of pore water pressure promoted the development of damage ; 4） It was proposed that internal pore water pressure could he monitored as a method to predict sudden disasters of the rock instability in deep mining engineering.