含孔洞裂隙岩体灌浆后力学特性的物理试验与数值模拟

Experimental and numerical simulation of the mechanical characteristics of rocks containing hole and flaw after grouting

对不同裂隙倾角的含孔洞裂隙模型试件进行单轴压缩试验,并使用RFPA2D软件进行数值模拟,对比孔洞不充填和完全灌浆充填2种工况,研究灌浆体对试件应力环境、破裂模式及力学特性参数的影响。试验与数值模拟研究结果均表明:灌浆体减轻了应力集中,表现为最大压应力和最大拉应力下降,降幅分别为7.6%～9.8%、0.4%～9.8%。试件破裂模式、力学特性参数及其孔洞灌浆充填后的变化幅度与预制裂隙倾角紧密相关,水平和竖直裂隙这2种结构型式的试件均呈现为穿切岩桥的破坏模式;而倾斜裂隙试件的破坏受预制裂隙控制,使得峰值强度和残余强度最小,但这2种参数孔洞灌浆充填后的增幅最大。与孔洞不充填试件相比,孔洞完全灌浆充填的物理模型和数值模型试件峰值强度的增幅分别为5.45%～23.33%、4.18%～14.29%,残余强度增幅分别达到31.68%～161.71%、22.54%～73.85%。

Uniaxial compression experiments and numerical simulation by RFPA 2D on model specimens containing a hole and a flaw with different flaw inclinations were conducted to investigate the influence of grouting body on the stress environment, failure mode and mechanical parameters of specimens. The specimens without and with grouting body were compared. The results of experimental and numerical simulations show that the grouting body reduces the stress concentration, the maximum compressive stress and tensile stress of specimens decrease, and their amplitude reductions are in the range of 7.6% to 9.8% and 0.4% to 9.8%, respectively. The failure modes, mechanical parameters and their variation amplitudes after filled are closely related to the inclination of the pre-existing flaw. A horizontal/vertical inclined flaw leads the specimens without and with grouting body to fail in a mode of cutting through the rock bridge. The peak and residual strength are the smallest and their amplifications are the highest in the case of an inclined flaw where the failure mode is controlled by the presence of such a flaw. Compared with the specimens without grouting body, the peak strength and residual stress of the physical and numerical model specimens with grouting body increase, and the peak strength amplifications are in the range of 5.45% to 23.33% and 4.18% to 14.29%, respectively, and the residual stress amplifications are in the range of 31.68% to 161.71% and 22.54% to 73.85%, respectively.