论文部分内容阅读
基于新疆库尉引水隧洞现场监测资料,对饱水土质隧洞变形特性及影响因素进行深入分析。根据其主导影响因素将土质隧洞的变形分为3个阶段:横向空间效应影响阶段→纵向空间效应+时间效应影响阶段→时间效应阶段,横向空间效应影响为开挖时出现塌方、冒顶的主要因素,可通过超前支护、减小横向空间面积等方式降低其影响;纵向空间效应+时间效应主导着第二阶段的变形,其合理的分离可为参数反演提供依据;第三阶段的时间效应主要为流变变形。对不同埋深、围岩类型以及支护强度影响下监测的变形数据的分析可知:低液限粉(黏)土整体性较好,主要发生与埋深有较大关系的形变变形,埋深越大,变形越大,且具有一定的流变特性;粉土夹砂层和粉细砂夹砾石排水量大,开挖过程中易发生小范围塌方,其变形主要以洞周一定范围内的松动变形为主,且与夹砂层的位置有较大关系,埋深对其变形影响不显著,在采取强支护措施及分步开挖方式下,监测到的变形量值均较小。支护结构在拱顶和边墙部位的变形特性有很大差异:拱顶变形稳定时间短,变形量小;低液限粉(黏)土围岩边墙处围岩塑性区范围随埋深增大,应力释放时间效应明显,形变压力不断增长,收敛变形量大。对于土质隧洞,钢拱架在限制围岩变形方面比钢格栅更为显著,考虑造价等因素,应根据不同地质条件、埋深合理选择支护方式。
Based on the on-site monitoring data of Kuwei diversion tunnel in Xinjiang, the deformation characteristics and influencing factors of the tunnel with saturated water and soil are analyzed in depth. According to the dominant factors, the deformation of soil tunnel is divided into three stages: horizontal space effect stage → vertical space effect + time effect stage → time effect stage. The horizontal space effect is the main factor of landslide and roof fall when excavation , The influence can be reduced by means of advanced support and reduction of lateral space area. The longitudinal space effect + time effect dominates the deformation of the second stage, and its reasonable separation can provide the basis for parameter inversion. The third stage of the time effect Mainly rheological deformation. Analysis of the deformation data monitored under the influence of different burial depths, surrounding rock types and supporting strengths shows that the integrity of the low-liquid limit powder (clay) is better, and deformation and deformation, which have a greater relationship with burial depth, mainly occur The bigger the deformation is, the larger the deformation is and the rheological characteristics are certain. The silt sand and fine sand gravel displace large amount of water, which is easy to occur in the excavation process. The deformation mainly depends on the loosening Deformation is dominant, and has a great relationship with the location of the sand layer. The depth has no significant effect on the deformation. Under strong support measures and step-by-step excavation methods, the deformation values monitored are small. The deformation characteristics of the support structure in the vault and side wall are quite different: the deformation and stability time of the vault is short and the deformation is small; the plastic zone of the surrounding rock of the low liquid limit powder (clay) Increases, the effect of stress release time is obvious, deformation pressure is increasing, and the amount of convergence deformation is large. For the soil tunnel, the steel arch frame is more significant than the steel grid in limiting the deformation of the surrounding rock. Considering the cost and other factors, it is reasonable to choose the support method according to the different geological conditions and the buried depth.