钻爆法施工隧道塌方风险量化评估模型及其应用

Establishment and application of a quantitative assessment model of collapse risk in tunnel excavated by drilling and blasting method

受地质条件和施工等因素的影响,钻爆法施工中塌方事故频频出现,造成人员伤亡、机械损坏、工期延误等不良后果。目前的风险评估方法多以定性为主,难以继续满足隧道安全风险管理的需要。根据风险定义,考虑围岩物理力学参数的变异性,应用Monte-Carlo方法和数值分析实现隧道塌方发生概率的定量化分析,并基于普氏平衡拱理论实现隧道塌方规模的定量化预测;结合施工人员、机械的时空分布特征及其易损性实现人员伤亡风险、工期延误风险和经济损失风险的定量化计算;利用ALARP原则和F-N曲线建立可量化的风险接受准则,实现塌方风险的定量化评估。结合工程案例,验证了模型在隧道等地下工程塌方风险定量化评估中的适用性。

Collapse always frequently occurs during the construction of tunnels due to the unfavorable geological conditions or other factors such as the excavation method,causing casualties,equipment damage,time delay or other adverse consequences.However,the current qualitative assessment method cannot satisfy the needs of project risk management.Hence,a novel quantitative assessment model of collapse risk is developed.Considering the variability of physical and mechanical parameters of surrounding rock,the probability of collapse is obtained by the Monte-Carlo method combined with the numerical method.The relevant zone of collapse is predicted by Protodyakonov's theory.With the predicted probability and zone of collapse,the risk of casualties,time delay and economic loss is analyzed quantitatively via introduction of spatiotemporal distribution index and vulnerability index.The quantitative assessment of collapse risk is realized by quantifiable risk acceptance criterion based on the way of ALARP principle and F-N curve.Finally,validated by engineering case history,the operability and applicability of the developed risk quantitative assessment model is illustrated.