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颗粒形状对隧道开挖砂性地层稳定性影响的力学响应分析
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Abstract:
颗粒形状是影响土体强度及变形特性的重要因素，现有研究主要聚焦于颗粒形状对土体物理力学性质的影响。为研究颗粒形状对隧道开挖后砂性地层稳定性的影响，选取典型的颗粒形状表征参数构建离散单元模型模拟隧道开挖，系统分析颗粒形状对隧道开挖后砂性地层应力重分布、地层变形及地层–隧道衬砌相互作用的演化规律。研究结果表明：隧道开挖后砂性地层会产生一定的土拱效应，土拱效应强弱由地层沉降及地层–隧道相互作用表征，尤其是土体的扁平颗粒比方正颗粒在隧道开挖后更有利于形成稳定的土拱。
Particle shape is an important factor affecting the strength and deformation characteristics of soils. The existing researches in this field mainly focus on the influence of particle shape on the physical and mechanical properties of soils. In order to explore the influence of particle shape on the stability of sandy ground after excavation, a series of discrete element models are established simulating tunnel excavation in ground with different representative particle shape descriptors. The influences of particle shape on evolutions of ground stress redistribution, ground settlement and ground-tunnel structure interaction after excavation are comprehensively investigated. The results show that there exists certain soil arching effect in cohesion less ground after tunnel excavation. The soil arching effect can be manifested from the ground settlement and ground-tunnel structure interaction. Especially, flat particles are more favorable for the formation of stable arching structures than squared particles.
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