浅埋轻轨隧道支护体应力监测及失稳控制

Stress Measurement and Deformation Control of Support System in Shallow Light Railway Tunnel

结合重庆市轻轨较新线大坪车站大跨度地下空间DK7+692断面施工支护体应力监测的工程实例,阐述了该大跨度地下空间支护结构的参数选择、地下空间的开挖方法、支护体结构的应力量测方法及测试手段;分析了支护体初期支护工字钢拱应力、锚杆轴力、喷射混凝土内应力、临时工字钢支撑应力、二次衬砌钢筋应力等测试结果和变化规律;确定了工字钢拱应力急剧增大而可能引起支护体系失稳的原因。在此基础上,针对施工中出现的问题,及时调整了施工方案及支护措施,控制了支护体系的失稳,避免施工中险情的发生,实现了隧道的信息化施工和施工安全。

Combined with the real example of monitoring pressure on the supporting system in the long span underground space of DK7 ＋ 692 section at Jiao - Xin line of Chongqing light railway, it is set forth the methods about choosing the support system and its parameter, digging methods of underground space, measuring and testing methods for the stress of the support system ; the testing results and variation pattern were analyzed for the stress of the initial supporting I - steel, axial stress of bolt, stress of shot - concrete, supporting pressure of temporary I - steel and stress of steel of the second lining, then, the reason for deformation of the support system induced by sharp increase of I - steel was determined. Based on this, considering the real problem, the construction plan and the support system is changed, the deformation of support system was under control and the danger was avoided, the informative construction and construction safety were realized.