坚硬岩体中马蹄形洞室岩爆破坏平面应变模型试验

为了探讨马蹄形地下洞室围岩岩爆破坏过程与机理,以单轴抗压强度(σc)、脆性系数(K)与冲击能量指数(WB)为概化指标,通过物理模型材料的正交试验,选取了合适的具有岩爆倾向性的坚硬脆性岩体物理模型材料,制作了长800 mm×宽800 mm×厚200 mm的马蹄形洞室物理模型试件,并在岩土工程大型真三轴物理模型试验机上进行高应力条件下平面应变物理模型试验。试验结果表明:在高地应力条件下,马蹄形洞室坚硬脆性围岩岩爆破坏主要在洞壁围岩初始破坏裂纹产生后,在极短的时间与极窄的加载区间产生的破坏,破坏具有突发性;洞室围岩在发生岩爆破坏后,围岩应力要进行重新调整,在相对较长时间与加荷区间内围岩表现相对稳定。岩爆破坏过程的物理模拟结果与工程实际基本一致。

Plane-strain model tests on rock-burst of horseshoe section caverns in hard and brittle rockmass

In order to discuss process and mechanism of rock-burst in the surrounding rock of horseshoe section caverns,a physical model,800 mm long and 800 mm wide and 200 mm thick with a horseshoe section cavern,was produced with hard brittle physical model materials from orthogonal experiments by the generalized indexes of uniaxial compressive strength(σc),brittleness coefficient(K) and exponential of strike energy(WB).The physical model was tested in the large triaxial model-test machine of geotechnical engineering under the high stress and plane strain condition.It was shown that a rock-burst which was paroxysmal in hard and brittle surrounding rock of horseshoe section cavern occurred during a transitory time in a limited loading-zone under the high stress condition when crack appeared,and that a relatively steady period appeared during relatively long time and a relatively broad loading-zone appeared after the rock-burst,following stress adjusting.The results of physical simulation were basically consistent with the actual engineering situation.