地下工程锚固界面力学模型及其时效性研究

地下工程锚固体接触界面的流变力学特性是锚固体产生时效性的重要因素。针对地下工程长期稳定性分析中常采用的锚固界面法向硬接触和切向黏结滑移突变常导致计算不收敛的困惑，建立了锚固界面法向刚度服从指数分布的软接触型式，并提出剪切面的非线性流变本构模型，解决了计算难以收敛的问题。该模型考虑了法向应力对剪切流变的影响，可以更真实地反映锚固界面流变的力学过程。将建立的锚固界面力学模型植入ABAQUS软件，并应用于地下工程的锚固时效性分析。研究成果表明：地下工程锚固界面产生的剪切流变导致锚杆应力增大，并使得预应力锚杆峰值的位置随着时间发生变化，且有向锚根转移的趋势。研究成果可为地下工程锚固的可靠性分析提供理论依据。

Constitutive model of anchorage interface in underground engineering and its time-effect analysis

The rheological property of anchorage interface is one of important problems of anchorage time-effect in underground engineering. Aiming at the defects of hard contact formulation in normal direction and discontinuity from bond to slip in tangential direction when analyzing long-term stability of underground engineering, a contact formulation which is an exponential softened pressure-overclosure relationship in normal direction and a continuous nonlinear constitutive model in tangential direction are proposed. The model solves the problem of converging hardly and reflects the process of shear rheological behavior truly and reasonably because of its consideration of normal stress. By the further development of ABAQUS code, the nonlinear rheological model of anchorage interface is applied to analyzing time-effect of anchorage in underground engineering. The main achievements are conducted as follows: anchor stress will increase with shear rheology of anchorage interface, the location of anchorage peak stress will change and move towards the end of anchor with the lapse of time. The research results provide the theoretical basis for deeply researching the reliability of anchorage in underground engineering.