开挖卸荷速率变化对岩质边坡应力应变影响作用研究

Influence of Excavation Unloading Rate on the Stress and Strain of Rock Slope

基于卸荷岩体力学理论及方法,应用FLAC3D有限差分计算软件,在数值分析中模拟不同速率的边坡开挖。并在不同开挖速率下,对考虑及不考虑边坡岩体卸荷变化条件下开挖边坡的应力应变特征进行了对比分析。结果表明:在考虑岩体开挖卸荷作用的前提下,开挖速率越慢,开挖过程中边坡模型的应力应变越小,塑性区范围也越小;而在不考虑岩体动态开挖卸荷作用时,开挖速率对边坡最终的应力应变以及塑性区大小并无直接影响。因此,在实际施工中应充分考虑动态卸荷作用以及开挖速率的影响,注意控制开挖进度,开挖后应对开挖边坡及时进行加固。

The excavation of slope with different unloading rates is simulated with FLAC3D finite difference method. The stress and strain of the slope in the presence and in the absence of unloading changes are compared and analyzed. Results showed that： in the presence of excavation unloading, the stress and strain and plastic zone of slope model in the construction process are smaller when the excavation rate is slower; while when the dynamic unloading effect is not considered, the stress, strain, and plastic zone is not affected directly by the excavation rate. Therefore, the effect of dynamic unloading effect should be fully considered in actual construction, the excavation progress should be controlled, and the slope should be reinforced timely after the excavation.