【摘要】 隧道进口施工一直是困扰大型隧道施工的技术难题,在偏压地段更是如此,结合张家口至石家庄高速公路北口隧道进口段工程,针对工程开挖后初期支护和坡体产生裂缝这一隧道进口段代表性工程问题展开了专项研究。采用理论分析与监测试验相结合的研究方法,在全面研究偏压隧道进口段工程裂缝发生机理的基础上,提出了非均匀支护控制措施,并通过控制效果监测数据的稳定性评价验证了机理和措施的合理性。研究结果表明:基于围岩压力和隧道开挖后松动圈、塑性区及变形计算理论,通过支护结构特征曲线与围岩支护需求曲线相结合,分析了北口隧道进口段初期支护和坡体裂缝发生机理;在裂缝发生机理研究的基础上,基于支护结构刚度思想确定了非均匀支护参数。更多还原

【Abstract】 Tunnel entrance construction has been a technical problem puzzled large-scale tunnel construction,especially in bias sections.A special research on the typical problem of the crack of initial supporting and slope after engineering excavating is conducted combining with the Beikou tunnel entrance project of Zhangjiakou-Shijiazhuang expressway in Hebei Province.Based on the comprehensive study of crack occurrence and development mechanism of bias tunnel entrance engineering,with the methods of theoretical analysis and monitoring test,non-uniform support and control measures are proposed,and the rationality of the mechanism and control measures is verified through the stability evaluation of control effect monitoring data.The results show that:(1) with the methods of surrounding rock pressure,broken-rock circle,plastic zone and deformation theories when the tunnel excavated,through combining support structure characteristics curve with wall rock support demand curve,the primary support and slope crack occurrence mechanism in the Beikou tunnel entrance are proposed;(2) based on the study of crack occurrence mechanism,non-uniform support parameters are defined using supporting structure stiffness thought.更多还原