超大直径泥水盾构开挖面破坏模式及力学行为多尺度模拟和试验研究

Due to the ultra-large diameter slurry shield passes through anisotropic mixed ground, the failure mode and mechanical behavior of shield tunneling face are of unique characteristics and one of the scientific problems needed to be urgently explored. Engineering facts has shown that the face stability for a large slurry shield-driving tunnel are mainly decided by the heterogeneity of sandy-clay mixed soils, the seepage of groundwater, the effect of slurry permeation and construction parameters, etc. However, current calculation models and methods are all focus on small and medium diameter tunnels and the homogeneous continuum theory, and the heterogeneous features of ultra-large diameter shield tunneling face failure cannot be taken into consideration. The suggested topic will investigate the failure mode and mechanical behavior of ultra-large diameter shield tunneling face by means of model test, rational solution，multi-scale numerical simulation and in-situ test. Main contents are as follows: (1) the research on the failure mode and evolution laws of ultra-large diameter slurry shield tunneling face under the influence of groundwater seepage and slurry permeation, etc. (2) the study on soil disturbance, soil arch effect and stability mechanism of ultra-large diameter slurry shield tunneling face crossing anisotropic soils; and (3) the establishment of calculation model and multi-scale calculation method. The aforementioned research achievement will further expand the current excavation theory of shield tunneling, and it will also lay a foundation for the revision of the shield tunneling construction code.

超大直径泥水盾构开挖面由于穿越非均质砂-粘混合地层，其破坏模式和力学行为具有特殊性，且是国内外盾构隧道迫切需要解决的科学难题。事实表明：超大直径泥水盾构开挖面稳定性主要决定于砂-粘混合地层的非均质特性、地下水渗流作用、泥浆渗透影响以及施工参数等关键因素。而现有盾构隧道开挖面稳定性计算模型和计算方法都是以中小直径盾构隧道和均质连续介质理论为基础，没有反映超大直径泥水盾构开挖面失稳呈现的非均质特性。本课题拟借助模型试验、理论分析、多尺度数值模拟和工程验证手段，深入研究超大直径泥水盾构开挖面的破坏模式和力学行为，主要开展：（1）研究超大直径泥水盾构开挖面在地下水渗流和泥浆渗透等因素影响下的破坏模式及其演化规律；（2）研究超大直径泥水盾构穿越非均质地层时开挖面的扰动影响分区、土拱性态与稳定机理，建立计算模型和多尺度计算方法。成果将进一步拓展现有盾构隧道开挖理论，并为盾构法隧道施工规范修订奠定基础。

超大直径泥水盾构开挖面由于穿越非均质砂-粘混合地层，其破坏模式和力学行为具有特殊性，且是国内外盾构隧道迫切需要解决的科学难题。事实表明：超大直径泥水.盾构开挖面稳定性主要决定于砂-粘混合地层的非均质特性、泥浆渗透影响以及施工参数等关键因素。而现有盾构隧道开挖面稳定性计算模型和计算方法都是以中小直径盾构隧道和均质连续介质理论为基础，没有反映超大直径泥水盾构开挖面失稳呈现的非均质特性。本课题采用模型试验、理论分析、多尺度数值模拟和工程验证手段，研究了超大直径泥水盾构开挖面的破坏模式和力学行为，主要研究成果：（1）获得了超大直径泥水盾构开挖面在复合地层下的破坏模式及其演化规律；（2）揭示了超大直径泥水盾构穿越非均质地层时开挖面的扰动影响分区、土拱性态与稳定机理，建立了计算模型和多尺度计算方法；（3）构建了开挖面支护压力计算平台（TBM-Studio），实现了盾构掘进开挖面稳定性的可视化分析。成果进一步拓展了现有盾构隧道开挖理论，并可为盾构法隧道施工规范修订奠定基础。