岩体结构控制作用随深度变化对比研究

More geohazards as rockburst and intensive squeezing occur with deepening of geoengineering. The rock mass structure controlling is commonly accepted and plays its roles in guiding previous shallow geoengineering. The structure is behaved dynamic changes in types and scales under disturbance of fast excavation and continuous deformation together with in-situ stress adjustemnt in large depth. Previous researches constructed one feasible model as one rock as cataclastic rockmass, one approach as engineering geological interaction matrix, and one viewpoint as rock mass structure dynamic controlling. The problems faced up to now is the obvious difference of classification values of rock mass quality, occurrence of complicated construction-triggered geohazards, mostly due to disagreemnet of engineering and research subject in scales. Then the mechanism of the structure and in-situ stress interaction, and the variation of geological models with depth is far from clarifying. Taking the geoengineering projects under design and construction as case examples, this research will focus on the regulations of rock mass structure controlling with deepening of geoeneering. Combination of geophysical exploration, borehole logging data at different depth, interaction matrix and analogy will be applied in the research. Database of in-situ stress and failure examples of geoengineering is to be built. The aim is to connect the geophysical profile with rock mass structure for clarify the variation and mechanism of rock mass structure controlling with deepening excavation.

大量深部地质工程建设发现，工程地质条件乃至地质模型与浅部有所不同。受环境和施工开挖等影响，一定深度下岩体结构会出现不同规模尺度动态变化，且影响地应力分布和调整。申请者前期研究初步构建了一岩-似层状碎裂岩体、一法-工程地质多因素关系矩阵法和一观-岩体结构动态控制观的研究模型。现面临向深部岩体结构、工程规模和研究样本三方尺度不同常导致岩体结构探查和观测结果不甚清晰、岩体质量级别在勘察和施工阶段划分结果常相差很大、施工地质灾害多发等问题。本研究拟通过构造体系和构造层分析基础上工程相对深度划分，用多因素关系矩阵法和工程类比法等，对比典型地质工程钻探和物探数据资料，场地微地震和隧道断面监测、物理参量反演、真三轴试验、物理模拟和数值计算相结合，提出结构动态控制初始和边界条件，建立岩体结构随深度变化模式，初步揭示岩体结构与地应力相互作用机理。此研究成果可为向深部拓展的重大和新型地质工程提供科学服务。

四年研究发现，深部工程地质条件或地质模型与浅部不同主要表现在岩体结构种类和受力边界条件差异。岩体结构在300米以下深度不同构造层显示构造幕次和施工开挖条件等影响，出现结构面倾角、密度和宽度的动态变化，且会作用到围岩引起应力不均匀分布。研究中将岩体结构、工程和研究样本三方面尺度匹配，使地面地质调查、物探和钻探对岩体结构性质和规模分类探测及其控制作用机理有了较好认识。研究发现岩体结构随深度对变形破坏的控制作用性质、强度和范围发生了变化，对流体和边界应力突变更为敏感，从而动力地质作用模型和重大工程地质设计至关重要。采用多因素关系矩阵法和工程类比法相结合，充分利用造山带和盆地不同构造单元典型地质工程钻探和物探技术资料，借助场地微震和隧道断面监测、物理参量反演、真三轴实验、物理模拟和数值计算相结合方法，采用基于构造单元和构造层分析基础上地质深度和物理深度划分工程相对深度，揭示岩体结构控制作用随深度变化机理，即浅部重力作用和深部侧向挤压力作用使浅表拉张破坏和深部剪切滑脱破坏（断坪和断坡）。深部工程地质条件评价采用结构各向异性即软硬层的交界面的流体重点监测和小范围层间构造模拟方法，为铜川陆相和焦石坝海相页岩气开发、巴基斯坦NJ引水隧洞等深部地质工程建设提供了科技支撑服务。