利用断裂力学理论, 在考虑动水压力作用的基础上, 研究了裂隙岩体中张开裂纹在受到垂直于裂纹长度方向 的应力为拉应力时继续扩展的条件及考虑动水压力的裂隙岩体裂纹扩展机理在裂隙岩体隧道突水( 泥) 的应用。结 果表明: 动水压力会改变裂纹尖端应力强度因子, 它能促使裂纹尖端附近的应力达到起裂临界值, 从而导致裂纹继 续扩展。在裂隙岩体隧道中, 动水压力一方面加大裂纹尖端应力强度因子, 使裂隙继续扩展; 另一方面动水压力的 冲刷作用导致隧道的水文地质条件不断恶化, 裂隙内充填介质产生渗透变形或者整体冲出后进入隧道, 造成隧道涌 突水( 泥) 。

Based o n t he theor y o f fracture mechanics and the effects of hydrodynamic pr essure o n the fractured ro ck, the condi2 tions that o pen crack in the f ractured ro ck continues to ex pand when it bears t he tensile st ress w hich is per pendicular to the length dir ection of the cr ack, and the application o f cr ack ex panding mechanism in tunnel w ater g ushing( mud) o f fr actur ed r ock wer e inv est igat ed in this paper . T he results show ed that : the hy dr odynamic pr essure changes the stress intensity factor at the cr ack tip by increasing the stress near crack tip to reach the cr itical v alue o f cr ack initiation, thereby causing cr ack ex pand. I n the fractured rock tunnel, hydro dy namic w ater pr essure can no t only incr ease t he str ess intensit y facto r at the crack tip to ex pand cr ack, but also deter io rate the hydrog eolog ical conditio ns in the tunnel due to its er osion actio n, and seepag e defo rmatio n o f the filling medium in fracture o ccurs o r filling medium can be w ashed aw ay to cause tunnel w ater g ushing( mud) .

国家自然科学基金青年项目( 41202213) ; 四川省教育厅自然科学自筹一般项目( 12ZB188 ) ; 成都理工大学青年基金资助项目 (2011QJ23)