The excavation disturbed zone plays an important role in the evaluation of tunnel stability. The identification of the excavation disturbed zone is perceived as a main concern. Taking the material meso-structure into account, this paper investigates the construction mechanical behavior in heterogeneous sand cobble stratum and aims to precisely predict the excavation disturbed zone. Firstly, the meso-scale numerical models were used to simulate tunnel excavation in sandy cobble strata, in which the large-sized rock blocks and fine-grained soil matrix were treated as separate constituents. Then, the stress redistribution and deformation performance in the ground during tunneling were explored in detail. Subsequently, combined with the deformation performance characteristics, a method for identifying the excavation disturbed zone was proposed. The boundary of the excavation disturbed zone can be identified by the displacement mutation point of the monitoring paths. Finally, a parametric study was performed to understand the influence of key factors on the excavation disturbed zone, including the rock meso-structure parameters, the soil matrix properties, and the tunnel geometry characteristics. The simulation results indicate that both the rock content and rock size have a significant impact on the excavation disturbed zone, the strength parameters and lateral pressure coefficient have a marked effect, and the tunnel radius and tunnel burial depth have a negligible influence on the excavation disturbed zone under the given conditions when normalized.

开挖扰动区在隧道稳定性评价中具有重要作用。开挖扰动区的识别被认为是一个主要问题。考虑到材料细观结构，研究了非均质砂卵石地层的施工力学行为，旨在精确预测开挖扰动区。首先，采用细观数值模型模拟砂卵石地层中的隧道开挖，其中大尺寸岩块和细粒土基体作为单独的成分处理。然后，详细探讨了隧道掘进过程中地层的应力重新分布和变形性能。随后，结合变形性能特点，提出了一种识别开挖扰动区的方法。通过监测路径的位移突变点可以识别开挖扰动区的边界。最后，通过参数研究来了解关键因素对开挖扰动区的影响，包括岩石细观结构参数、土壤基质特性和隧道几何特征。模拟结果表明，岩石含量和岩石尺寸均对开挖扰动区有显着影响，强度参数和侧压系数影响显着，隧道半径和隧道埋深对开挖扰动区影响可忽略不计。归一化时给定条件下的区域。进行了参数研究，以了解关键因素对开挖扰动区的影响，包括岩石细观结构参数、土壤基质特性和隧道几何特征。模拟结果表明，岩石含量和岩石尺寸均对开挖扰动区有显着影响，强度参数和侧压系数影响显着，隧道半径和隧道埋深对开挖扰动区影响可忽略不计。归一化时给定条件下的区域。进行了参数研究，以了解关键因素对开挖扰动区的影响，包括岩石细观结构参数、土壤基质特性和隧道几何特征。模拟结果表明，岩石含量和岩石尺寸均对开挖扰动区有显着影响，强度参数和侧压系数影响显着，隧道半径和隧道埋深对开挖扰动区影响可忽略不计。归一化时给定条件下的区域。