深地下洞室群开挖诱发的节理岩体松动变形演化机理

Based on excavation of deep complex for underground powerhouse in mountainous region West China, aiming at deformation evolvement problems induced by jointed rockmass loosening during disturbance from blasting excavation, this project starts from loosening effect of jointed rockmass to study rockmass deformation evolvement, with theories such as explosive dynamics, rock dynamics, stress wave theory, as well as using theoretical calculation, laboratory experiment, field tests, numerical simulation, signal analysis. It is proposed to study the influencing pattern of different blasting parameters and excavation procedures on induced frequency and amplitude of stress waves, and to reveal interaction mechanism between joint characteristic and stress wave frequency and amplitude. By studying unloading wave on the excavation side of middle partition rockmass and reflection-induces tensile wave on the other side, stress wave propagation and frequency-amplitude attenuation are revealed, and dynamic response of jointed rock mass and deformation evolvement process on both sides of the middle partition wall is determined, to understand the explicit deformation evolvement process for jointed rockmass induced by multiple blasting excavation with increasing distance to the source, aiming to establish back-analysis evaluation method with frequency band analysis on vibration response of surrounding rockmass, as well as control methods on deformation evolvement. The research result can find wide application prospects in the fields of water conservancy and hydropower engineering,deep mining and dispose of nuclear waste,etc.

以我国西部高山深谷地区大规模水电站地下厂房洞室群建设为背景，针对深部岩体爆破开挖动力扰动诱发节理岩体松动变形演化机理和控制问题，借助爆炸力学、岩石动力学与应力波理论，综合利用理论计算、室内模型试验、现场测试与监测、数值模拟、频谱分析等手段，建立不同爆破参数和开挖程序激发应力波的幅值和频率的力学模型，揭示深部岩体节理面特性与不同频谱与幅值应力波的相互作用机制；研究中隔墙本洞侧受到的卸载波作用和邻洞侧受到的爆炸应力波反射拉伸作用，揭示节理岩体中应力波传播与幅值频率衰减机制，确定本洞与邻洞松动岩体节理的动力响应特性和围岩松动变形演化过程，明确高地应力条件下爆心距逐渐增大过程中多次爆破开挖引起的围岩松动变形演化过程，探索基于围岩振动响应频谱分析的围岩变形参数反演评价方法与围岩变形演化控制方法。项目研究成果在水利水电、深部采矿和核废料深埋处置等领域具有广阔的应用前景。

以我国西南高山深谷地区特大型水电站地下厂房洞室群施工建设为背景，采用现场测试与理论分析为主，室内实验和工程类比相结合的方法，研究高地应力条件下含平行节理的深部岩体爆破开挖瞬态卸荷与爆炸荷载激发应力波引起的深地下洞室群中隔墙内部节理面松动机制与围岩变形演化特性，探索不同爆破参数与开挖条件激发应力波的频谱特性，揭示应力波与节理面的相互作用机制，明确应力波频率、幅值、节理间距和开度之间的相互影响规律，并考虑节理倾角与物理力学特性变化的影响；基于节理面中应力波幅值和频率的衰减作用，研究不同距离节理面受到的应力波幅频特性，从而研究开挖掌子面不断推进引起的节理面反复振动响应与围岩变形演化计算方法；探索基于围岩振动响应频谱分析的围岩变形参数反演评价方法与围岩变形演化控制方法。研究成果可为深地下洞室群开挖过程中节理动态松动测试评估、围岩变形演化预测、支护优化设计与安全控制以及渗流控制等方面提供理论依据，对加深深部围岩变形机理及演化过程的理解具有重要的理论意义，在水利水电、核废料处置、石油采储、交通建设等岩体工程的优化设计与施工方面有较为广阔的应用前景。