大断面黄土隧道开挖工法对比分析与选择

Comparative Analysis and Selection of Construction Methods for Large Section Loess Tunnel

研究目的:通过对优化后的大断面黄土隧道开挖工法进行基于有限元理论的实际施工过程仿真计算,分析开挖过程中的围岩应力场、位移场、支护结构强度变化等规律,并结合工法的资源配置、施工进度和监控量测结果来综合确定各种工法的适用范围,从而选择合理的超大断面黄土隧道开挖工法。研究结论:结合超大断面黄土隧道的围岩地质条件,研究了隧道开挖工法CRD法、短台阶七步法和双侧壁导坑法在进度指标、下沉量、施工工序、资源配置、施工风险、施工成本等方面的定性和定量指标,对传统的开挖方法进行了工序和支护方法的优化,提出了优化后各工法的适应范围和优缺点,可为类似工程提供借鉴。

Research purposes： Based on using the finite element theory to do the simulation calculation of the actual construction process of large-section loess tunnel with the optimized excavation method,the analyses are made for the change regulations of stress field,displacement field and structural strength of surrounding rock,and the applicable scopes of the different construction methods are determined according to the allocation of resources,construction progress and monitored results for the purpose of select a reasonable construction method for large section loess tunnel.Research conclusions：Combined with the geological condition of surrounding rock of large section loess tunnel,the researches are done on the qualitative and quantitative indicators of construction process,subsidence,construction order,resource allocation,construction risks and construction costs of construction large section loess tunnel with CRD method,short bench 7-step method and twine side wall pilot tunnel method.In addition,the traditional excavation method is optimized in the construction order and support method,and the advantages and disadvantages of the different construction methods are offered to provide the reference to the similar works.