基于应变能密度梯度的岩爆发生与治理研究

Rockburst is commonly encountered geological disasters in the excavation of tunnels at high in situ stresses. The yielding bolt is being commonly used to treat such a disaster. The yielding bolt is designed based on the energy balance principle. But the results are of big difference as the values of the design parameters cannot be unified. Based on the theory of energy density by Salamon, the mechanism of the forecast and treatment on the rockburt are studied using theoretical and experimental measures. From the theoretical aspect, forecast of the rockburst will be discussed according to the gradient and concentration of the strain energy density. The non-circular tunnels under the action of complicated in situ stresses will be theoretical analyzed. In the experimental aspect, both pull out test and rockburst experiments on reinforced fractured rock will be carried out. The pull out test gives more specific support parameters of certain kinds of full-length bonded bolt and yielding bolt. The rockburst experiments are expected for getting to revealing the reinforcing mechanism of the bolts on the fracture rockburst, and in which the gradient of the strain energy density is considered as well. Combining the theoretical and experimental results, we may come to the quantitative indexes for rockburst forecast and treatment. Besides, in order for reducing the probability of rockburst, shape optimization is to be conducted as well. This research will enrich the theory of energy density, and will provide theoretical and technical guidance for the forecast and treatment of rockburst.

岩爆现象是高地应力作用下隧洞施工过程中常遇到的地质灾害，屈服锚杆是目前常用的工程措施之一，其设计是基于能量平衡理论，但是由于设计参数取值不统一，给屈服锚杆的设计带来不便。本项目以Salamon提出的应变能密度理论为基础，结合理论解析和室内试验探讨岩爆的发生及治理机理。理论方面，从应变能密度梯度角度研究复杂地应力条件下非圆形隧道围岩内岩爆的孕育、发生机理；试验方面，室内拉拔试验着重研究锚固体自身及锚杆、围岩之间界面性质对锚固参数的影响，为锚杆的计算提供更准确的设计依据；岩爆模拟试验为了实现应变能密度梯度设计梯度加载，重点探讨屈服锚杆对裂隙型岩爆的治理机理。然后，将理论与试验成果相结合，提出基于应变能密度梯度的岩爆发生与治理的定量评价指标。此外为了降低岩爆发生概率，还从应变能密度角度对隧洞开挖断面形状进行优化。本课题丰富了岩爆的能量理论，有望为岩爆的预防和治理提供一定理论基础和参考价值。

岩爆现象是高地应力作用下隧洞施工过程中常遇到的地质灾害，屈服锚杆是目前常用的工程措施之一，其设计是基于能量平衡理论，但是由于设计参数取值不统一，给屈服锚杆的设计带来不便。本项目以Salamon提出的应变能密度理论为基础，结合理论解析和室内试验探讨岩爆的发生及治理机理。理论方面，从应变能密度梯度角度研究复杂地应力条件下非圆形隧道围岩内岩爆的孕育、发展、发生机理；试验方面，室内拉拔试验着重研究锚固体自身及锚杆、围岩之间界面性质对锚固参数的影响，为锚杆的计算提供更准确的设计依据；岩爆模拟试验为了实现应变能密度梯度设计梯度加载，重点探讨屈服锚杆对裂隙型岩爆的治理机理。然后，将理论与试验成果相结合，提出基于应变能密度梯度的岩爆发生与治理的定量评价指标。此外为了降低岩爆发生概率，还从应变能密度角度对隧洞开挖断面形状进行优化。本课题丰富了岩爆的能量理论，有望为岩爆的预防和治理提供一定理论基础和参考价值。