复杂结构形式隧道的围岩位移监测分析

 厦门市梧村隧道为双向六车道隧道，隧道结构形式设计复杂，分别由双连拱、小净距、初期支护连拱和分离式隧道组成。现场监测工作以隧道拱顶沉降和围岩收敛为主，结合施工措施和开挖工序进行全面分析。研究成果表明：三导洞法施工主洞沉降所占比例不到侧导洞沉降的一半，双连拱隧道结构型式适用于对沉降控制要求较高的隧道工程；CRD1部开挖产生的拱顶沉降可以超过累计沉降值的50%；核心土开挖后布设测点造成的总损失量约占累计沉降值的37.5%；采用全断面帷幕注浆措施加固围岩对控制隧道拱顶沉降取得较好的效果；管棚区域出现较大下沉与管棚工作室的断面稍大以及管棚两端受其自重影响较大有关；临时支护的拆除对拱顶沉降和围岩收敛的影响较小；开挖和注浆是引起围岩出现较大收敛变形的主要施工因素，其中注浆对围岩的收敛位移影响更大；初期支护连拱隧道右洞开挖对左洞二次衬砌的收敛稳定有一定的影响。

MONITORING ANALYSIS OF SURROUNDING ROCK DISPLACEMENT OF COMPLEX STRUCTURE TUNNEL

Wucun tunnel is a two-way and six-lane tunnel with complex structure in Xiamen City,which is composed of double-arch tunnel,small-distance tunnel,initially supported multi-arch tunnel and split tunnel. Vault settlement and convergence of surrounding rock are the main in-situ monitoring work,and the monitoring results are comprehensively analyzed combined with the measures and procedures of tunnel excavation. Research results show that vault settlement in main tunnel is less than half of that in guide hole in three-hole method construction area;and it is shown that the double-arch structure is applicable to the tunnel with higher settlement control requirement. Vault settlement derived from CRD1 can exceed half of the total value settlement during the excavation period. If the measuring point is embedded after excavation of core soil,the lost settlement will be approximately 37.5% of the total. Surrounding rock can be reinforced by full-face curtain grouting,which achieves better control in vault settlement than in convergence of surrounding rock. Under the influence of dead weight and larger cross-section of pipe roof chamber,larger vault settlement appears in pipe roof area. The removal of temporary support has less impact on the displacement of surrounding rock. Construction factors such as excavation mainly lead to larger convergence deformation as well as grouting;the latter produces a greater impact. Excavation in right tunnel has a certain impact on secondary lining in left tunnel.