Abstract:

To explore the influence of different joint occurrences on the damage and failure of tunnel rock mass under the coupling action of high stressseepage, based on the onsite monitoring results of high stress and seepage flow in tunnels, a numerical model of joint rock mass under stressseepage coupling is established using threedimensional discrete element software, and the distribution characteristics of seepage fields after excavation of joint rock masses and the influence of different joint production conditions on the seepage pattern and plastic zone failure of surrounding rocks are analyzed. The results show the following: (1) The joint inclination angle plays a leading role in the distribution pattern of the seepage field, the tunnel seepage field shows a funnel shape after excavation, and the deflection occurs with the direction of inclination to form a parallel "oblique funnel". (2) The larger the inclination angle, the larger the area of surrounding rock destruction; the joint spacing plays a leading role in the change amplitude of the seepage field, and the overall trend is to increase first, then decrease, and finally stabilize. (3) The area of the plastic zone increases by 10.29% for each doubling of the joint spacing; the difference in the initial gap width of the joint changes the permeability of the joint surface, and the gap width development along the radial direction of 14 m is mainly affected by the coupling of high stressseepage.

Key words:  jointed rock mass, tunnel, discrete element method, seepagestress coupling, joint obstetrics, seepage field, plastic zone