干湿与冻融循环条件下炭质泥岩路堑边坡蠕变损伤机理及稳定性研究

The creep damage evolution of weak fractured rock mass has been one of the difficulties of today's research. In the condition of dry-wet circulation and freeze-thaw cycles, the question of the deformation and damage of carbonaceous mudstone cutting slope has been a major bottleneck. For this propose, the carbonaceous mudstone microstructure damage evolution mechanism was discussed in this roject by some methods, such as scanning electron microscope, polarizing microscope, energy spectrum analysis, X-ray diffraction (XRD) and so on. With the utilization of the image analysis and CT data (CT & variances), carbonaceous shale microstructure damage evolution rule nder complicated stress (deviatoric stress) was researched based on triaxial compression test and synchronous scanning technology by CT machine. Based on the macro mesoscopic damage theory, a damage evolution equation of dry-wet circulation and the freeze-thaw cycle to fractured rock mass of different levels was established and the damage evolution of rock mass of carbonaceous mudstone slope was discussed and a three dimensional fractured rock mass damage constitutive relations was established. In order to investigate the deformation and isaster evolution mechanism and establish the instability, projection, forecast theoretical systems of the carbonaceous mudstone cutting slope, the creep damage constitutive model was stablished by means of creep test. The results have important theoretical and engineering application value for the prevention and control of soft rock slope.

软弱裂隙岩体蠕变损伤演化一直是当今研究的热点与难点之一， 在干湿循环与冻融循环条件下炭质泥岩岩体损伤使得路堑边坡变形和破坏已成为高速公路边坡防护一个主要瓶颈。为此，本项目通过扫描电镜、偏光显微镜、能谱分析、X射线衍射等手段分析炭质泥岩微观结构、矿物成分，探讨炭质泥岩微结构损伤演化机制；利用三轴压缩试验与CT机同步扫描技术，借助于图像分析和CT数据（CT数、方差）研究复杂应力下（偏应力）炭质页岩微结构损伤演化规律，基于宏细观损伤理论，建立干湿循环和冻融循环与不同应力水平裂隙岩体的损伤演化方程，研究炭质泥岩路堑边坡岩体损伤演化随时间和深度变化规律，并建立三维裂隙岩体的损伤本构关系。通过蠕变试验建立炭质泥岩蠕变损伤本构模型，研究炭质泥岩路堑边坡变形机制和灾害演变机理，构建炭质泥岩路堑边坡失稳、预测、预报理论体系。其成果对软岩边坡防治具有重要的理论价值和工程应用价值。

炭质泥岩在我国中西部地区分布广泛。炭质泥岩路堑边坡开挖暴露后，受干湿与冻融作用风化、崩解，导致沿线路堑边坡失稳、崩塌，已严重影响了我国西部高速公路建设。项目以广西宜州至六寨高速公路和株洲市迎宾大道为工程依托，利用室内试验、数值模拟和理论分析等手段，研究了干湿与冻融循环条件下炭质泥岩的蠕变损伤机理及稳定性分析。通过开展系列细观试验，研究了干湿与冻融循环作用下炭质泥岩细观结构、矿物成份及化学成份的演变规律，揭示了炭质泥岩的细观损伤机理。根据三轴压缩试验结果，建立了考虑孔隙压缩变形及裂隙扩张的损伤演化方程，探讨了炭质泥岩渐进破坏过程的损伤演化。开展了干湿与冻融作用下炭质泥岩的蠕变试验研究，提出了炭质泥岩长期强度的确定方法；并基于损伤理论和断裂力学，建立了干湿与冻融循环作用下炭质泥岩的蠕变损伤模型。利用FLAC3D平台，开发了损伤岩体边坡稳定性分析的计算程序，提出了干湿与冻融作用下炭质泥岩边坡稳定性的评价方法。其成果可为软岩路堑边坡防治理论研究和工程应用提供依据。