炭质泥岩路堑边坡湿化变形机理与生态稳固技术研究

Along with the rapid development of highway construction, in the carbonaceous mudstone area highway construction has been unable to avoid. However, slope instability made by carbonaceous mudstone in water softening weathering disintegrating and ecological protection failure has become a major bottleneck in highway construction process. Therefore, the microstructure of carbonaceous shale, mineral composition were analysed through scanning electron microscopy, polarizing microscope, spectrum analysis, diffraction of X-ray and some other means, and water rock action microstructure damage evolution mechanism was discussed. Use of slaking deformation test and CT machine synchronous scanning technology, and with the help of image analysis and computed tomography data (CT number and variance) study the carbonaceous shale microstructure damage evolution mechanism in complex stress situation (deviatoric stress), meanwhile establish the carbonaceous mudstone slaking damage evolution equation and constitutive model, and simulate the slaking deformation and failure mechanism of carbonaceous shale slope. Soft rock slope curing and ecological protection theory and methods was built by develop the carbonaceous mudstone curing agent and soil stabilizer, which could change the permeability of carbonaceous mudstone and disintegrating properties, increase soil water stability of ecological revetment and the resistance to erosion ability. The results have important theoretical and engineering application value to prevention and control the soft rock slope.

随着我国高速公路建设的迅速发展，在炭质泥岩地区修建高速公路已无法避免。然而，炭质泥岩遇水软化风化崩解使得路堑边坡失稳和生态防护失效问题已成为制约高速公路建设的一个主要瓶颈。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页岩微观结构、矿物成分，探讨水岩作用微结构损伤演化机制；利用湿化变形试验与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，建立炭质泥岩湿化损伤演化方程及本构模型；模拟炭质页岩路堑边坡湿化变形与破坏机理。通过研制炭质泥岩固化剂和土壤稳固剂，改变炭质泥岩自身渗透性和崩解特性、增强生态护坡土壤的水稳性和抗冲刷能力，构建软岩边坡固化与生态防护理论、技术方法。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。

炭质泥岩遇水软化易崩解并逐渐成泥土状带来的边坡崩塌和滑坡等地质灾害已成为高速公路建设中的主要瓶颈。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，通过工程地质调查、室内试验、现场试验、数值模拟等手段，开展炭质泥岩路堑边坡湿化变形机理与生态稳固技术研究，研究取得以下成果：引入分形理论，建立炭质泥岩崩解分形理论模型。根据湿化变形试验，提出了修正的双线法，建立了炭质泥岩湿化变形与轴向偏应力 数学模型。利用三轴仪湿化变形试验与CT机同步扫描技术，通过图像分析和CT数据（CT数、方差）研究复杂应力下（偏应力）炭质泥岩微结构损伤演化规律。建立了炭质泥岩湿化变形邓肯—张模型，在FLAC3D平台上二次开发，通过数值模拟研究炭质泥岩路堑边坡湿化变形破坏机理。研制出聚合物水泥新型固化剂和土壤稳固剂(羟丙基甲基纤维素醚和可分散乳胶粉合成)，确定了高分子稳固剂的最佳掺量为2%，并在改性土中添加聚丙烯纤维6‰将大大提高客土的水稳性和抗冲刷能力。构建了炭质泥岩边坡生态防护架构:坡面格构梁（锚杆）加固——边坡表面固化——客土加入土壤稳固剂喷播植草。其成果为易风化崩解类软岩边坡防护提供了全新的思路与方法。