超大直径盾构隧道穿越岩溶发育区地表注浆合理加固范围

为研究超大直径盾构隧道穿越岩溶发育区地表注浆合理加固范围,以武汉市某在建工程为依托,设计了以围岩等级、溶洞尺寸及溶洞充填范围为影响因素的正交试验,采用了三维数值方法求解不同方位溶洞与超大直径盾构隧道的最小安全距离,并提出了以最小安全距离主要因素为分段计算准则的地表注浆加固范围确定方法。结果表明：当溶洞位于隧道上方、侧方及下方时,最小安全距离的主要影响因素分别为溶洞尺寸、围岩等级及溶洞尺寸；当溶洞位于隧道上方时,分为4个区段,加固范围在12m~22.5m之间,当溶洞位于隧道侧方时,分为4个区段,加固范围在8m~15m之间,当溶洞位于隧道下方时,分为5个区段,加固范围在8m~15.5m之间。研究成果可为类似工程注浆设计与施工提供参考。

Research on Reasonable Reinforcement Range of Surface Grouting for Super Large Diameter Shield Tunnel through Karst Development Area

In order to study the reasonable reinforcement range of surface grouting for super large diameter shield tunnel through karst development area, based on an engineering under construction in Wuhan, this paper designed an orthogonal test with surrounding rock grade, karst cave size and cave filling range as the influencing factors, used the three-dimensional numerical method to figure out the minimum safety distance between karst caves in different directions and the super large diameter shield tunnel, and a method for determining the surface grouting reinforcement range was proposed, which takes the main affecting factor of the minimum safety distance as the segment calculation criterion. The results show that, when the cave is located above, on the side and below the tunnel, the main factors affecting the minimum safety distance respectively are the karst cave size, surrounding rock grade and karst cave size. When the karst cave is located above the tunnel, the karst development area is divided into 4 sections, and the reinforcement range is between 12m and 22.5m. When the karst cave is located on the side of the tunnel, the karst development area is divided into 4 sections and the reinforcement range is between 8m and 15m. When the karst cave is located below the tunnel, the karst development area is divided into 5 sections and the reinforcement range is between 8m and 15.5m. The research achievements in this paper can provide references for grouting design and construction of similar projects.