基于流-固耦合的盾构隧道开挖面稳定性研究

发布时间：2018-12-06 08:36

【摘要】：利用FLAC3D建立三维数值模型,对考虑完全流-固耦合效应的盾构隧道开挖面失稳过程进行模拟和验证,并进一步分析水位高度、渗流时间对开挖面变形、地表沉降和孔隙水压力的影响。研究表明:开挖面变形随支护压力比的减小经历3个阶段的变化,且与土体塑性区的发展密切相关;相比于无水状态,考虑流-固耦合效应的开挖面稳定性显著降低,随水位的升高、渗流时间的增大,开挖面发生失稳破坏的支护压力比明显增大;支护压力比(表征支护压力)的减小将导致开挖面前方一定范围的孔隙水压力减小,靠近开挖面的孔隙水压力受扰动程度加剧,形成"漏斗状"的影响区;开挖面失稳导致土体位移场延伸至地表,引起地表产生明显的沉降变形,在不同的变形阶段开挖面中心点位移与最大地表沉降分别呈抛物线相关和线性相关。
[Abstract]:A three-dimensional numerical model is established by using FLAC3D to simulate and verify the instability process of excavation surface of shield tunnel considering the complete fluid-solid coupling effect. Furthermore, the deformation of excavated surface by water level height and seepage time is analyzed. The influence of surface subsidence and pore water pressure. The results show that the deformation of excavated face changes in three stages with the decrease of support pressure ratio, and is closely related to the development of soil plastic zone. Compared with the anhydrous state, the stability of the excavated face considering the fluid-solid coupling effect decreases significantly. With the increase of the water level and the seepage time, the support pressure ratio of the excavating face with instability failure is obviously increased. The decrease of the support pressure ratio (indicating the support pressure) will lead to the decrease of pore water pressure in a certain range in front of the excavation surface, and the pore water pressure near the excavating surface will be aggravated by disturbance, forming a "funnel-shaped" influence zone. The instability of excavation surface leads to the extension of soil displacement field to the surface, which results in obvious subsidence and deformation. In different deformation stages, the center displacement of excavated surface and the maximum surface settlement are parabolic and linear respectively.
【作者单位】：保利(成都)实业有限公司;同济大学土木工程学院地下建筑与工程系;
【基金】：国家重点基础研究发展计划(973计划)项目(2015CB057800) 国家重点研发计划(2016YFC0800204)
【分类号】：U455.43

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