黄土深埋大直径盾构隧道围岩压力研究

为研究黄土深埋大直径盾构隧道围岩压力，引入黄土的结构性参数对芬纳公式进行修正，基于围岩与衬砌间的相互作用关系求解了围岩塑性区半径表达式，给出了黄土深埋大直径盾构隧道围岩压力的计算公式。并以某黄土深埋大直径盾构隧道为例，分析了应力比结构性参数对围岩压力的影响，并将三维有限元数值计算与理论分析结果进行了对比。结果表明，围岩塑性区半径和作用在管片结构上的围岩压力随着应力比结构性参数减小在不断增大；盾构掘进后围岩压力的最大值与黄土结构性参数为1时的围岩压力理论计算值比较吻合，盾构施工扰动会导致黄土结构性减弱。最后给出了黄土盾构隧道施工与管片设计的建议。

Surrounding rock pressure of loess deep large-diameter shield tunnel

To study the surrounding rock pressure of loess deep large-diameter shield tunnel, the structural parameter of loess was introduced to modify the Fenner formula. Based on the interaction between the surrounding rock and the lining, the formula of plastic zone radius of surrounding rock was solved, and the calculation formula of surrounding rock pressure of the loess deep large-diameter shield tunnel was provided. Taking a deep large-diameter shield tunnel in loess as an example, the influence of structural parameter of stress ratio on surrounding rock pressure was analyzed, and the numerical calculation results of three-dimensional finite element was compared with theoretical analysis results. The results show that the radius of the surrounding rock plastic zone and rock pressure acting on the segment gradually increase with the decreases of structural parameters; the maximum value of surrounding rock pressure after shield tunneling is found in agreement with the theoretical calculation value of surrounding pressure when the structural parameter of loess is 1-Shield construction will cause loess structurally weakened. Finally, suggestions for loess shield construction and segment design were given.