深部工程高应力型软岩流变扰动的分数阶导数建模

Focused on both time-dependent disasters and long-term stability issue of surrounding rock caused by the perturbation effect of high stressed soft rock in deep engineering, in the background of high stressed soft rock deep engineering (underground energy engineering reserves, high-level radioactive nuclear waste disposal engineering in deep underground etc.), a series of tests covering multi-scale approaches will be performed, including rheological test of high stressed soft rock under different rheological perturbation combined effect, acoustic emission test, acoustic monitoring, CT scanning approach etc. This project plans to survey the nonlinear evolution characteristics of crack development at different rheological stages of rock suffering from different perturbations, and then to reveal the mechanical characteristics of rheological perturbation and the time-dependent damage rupture law of high stress soft rock, and then to built a model accurately reflecting rheological perturbation effect of high stressed soft rock with fractional derivatives, and finally to develop the corresponding numerical solution of the nonlinear dynamic analysis, and thus to constitute the rheological perturbation effect and long-term stability analysis and evaluation system of high stressed soft rock in deep engineering.

针对深部工程高应力型软岩开挖卸荷后，遭受扰动作用诱发的时效灾变现象及由此引发的围岩长期稳定性问题，拟以深部工程（能源地下储备工程、高放核废物深地下处置工程等）高应力型软岩为背景，通过开展一系列流变与扰动应力波组合作用下的高应力软岩流变扰动试验，综合采用声发射和声波监测、CT实时扫描等多种技术手段，调查在岩石不同流变阶段遭受不同应力波扰动、不同方向扰动所引起的裂纹扩展、搭接、贯通的非线性演化特征，揭示高应力型软岩的流变扰动力学特征与时效损伤破裂规律，借助分数阶导数工具，构建能精确反映深部工程高应力型软岩卸荷流变扰动的力学模型，发展相应的非线性动力数值计算方法，形成一套深埋地下工程高应力型软岩的流变扰动效应及长期稳定性分析方法和评价体系。

项目针对深部工程高应力型软岩流变扰动时效破坏问题，基于高应力流变与微扰动应力波组合作用下的花岗岩蠕变试验，采用声发射和声波监测等技术手段，阐述了高应力花岗岩在不同流变阶段遭受微应力波扰动的力学响应和破坏特征，揭示了花岗岩流变扰动效应的宏细观时效演化机制，创建了相应的损伤渐进破裂的分数阶导数力学模型。运用近场动力学方法，考虑扰动作用及其过程中的惯性力，在ABAQUS有限元软件的基础上二次开发，提出了较为快速、高效的动力破坏数值分析方法，实现了连续介质的变形计算与非连续介质的破坏计算间的无缝衔接，数值再现了高应力下花岗岩自岩石内部微裂纹萌生、聚集发育成宏观裂纹、再到失稳破坏的时效破坏过程。项目研究成果为深部岩体工程流变扰动时效灾变预测及围岩长期稳定性评价提供了有效的途径，也为深部工程的规范设计与安全施工提供科学依据和技术支撑。