快速隆升典型河段复杂结构岩体灾变与水库工程活动互馈机理研究

Qinghai-Tibet Plateau rapidly uplift gives rise to the elevation of its southeast fringe from 4000m down to around 1500m and abundant in water energy. Nowadays the uplift velocity of Qinghai-Tibet Plateau is 5～10mm/a. Valley with high ground stress deep cutted and intensified unloading, frequently geological disasters, human being activities and Geological environment has been drawn great attentions. The proposed project will based on the special background of t Qinghai-Tibet Plateau uplift, and takes the complex structure of rock mass with high concentrated ground stress as a kernel, following the research thought of geological background→structure rock mass→stress response→evolution process→disaster cause mechanisms→engineering-environment mutual feed effect→countermeasure of geological disaster prevention. Based on the size effect principle of fractured rockmass representative element volume, set up fractured rockmass structural equivalent model, and composite macro-geological structural framework, soft rock micro-structure, to establish integrated geological structure equivalent model with three layers structure features, superimposing high ground stress boundary condition to obtain integrated geo-mechanics structural equivalent model, to simulate deformation and failure mechanism of structural rock slope. To summary the distribution law of potential disasters bodies, taking into account the impact of engineering activities, evaluating evolution tendency and the mechanisms of mutual feed effect of potential disaster body under the engineering impact; developing a new classification system of geological disaster by modern maths theory based on key engineering safety, put forward rational disaster prevention counterplan. To provide a scientific guidance for utilizing energy of deep cut valley under background of Qinghai-Tibet Plateau rapid uplift.

青藏高原快速隆升致其东南缘高程从4000m迅速降到1500m，水能丰富，目前青藏高原隆升速度达5～10mm/a。高地应力谷坡深切强卸荷，地灾频发，工程活动与地质环境互馈机理备受关注。本项目拟以快速隆升的青藏高原为特殊地质背景，高地应力岸坡岩体复杂结构为核心，遵循地质背景→岩体结构 →应力响应→过程演化→灾变机理→工程－环境互馈效应→地灾防控对策的研究思路。基于裂隙岩体表征单元体REV之尺寸效应的原理，构建裂隙岩体结构等效模型，进而叠加宏观地质构造格架、软岩微观结构，形成三层次结构的综合地质结构等效模型，迭加高地应力等边界条件构建综合地质力学结构等效模型，模拟卸荷条件下岸坡岩体结构灾变机理，总结潜灾体分布规律，研究工程活动与地质环境的互馈机理，运用现代应用数学构建以工程安全为导向的潜灾体分类系统，提出合理的地灾防控对策。为快速隆升青藏高原及周边河段水电工程开发提供科学指导。

以快速隆升青藏高原东南缘高程陡变带、高地应力、深卸荷地质构造为背景，选择金沙江上游5个典型河段，即巴塘-昌波河口(40km)，美荣楼-青龙(40km)，达日-达拉(21km)，羊拉大桥-奔子栏(33km)，古学乡-定曲河口(11km)。以自然历史地质过程机制与岩体结构控制理论为指导，以3S技术为支撑，7次赴现场，共165天，每次现场均8人。对典型河段的岸坡岩体结构，大型潜灾单体进行了筛查，取得了3181个地质点，共得到大型堆积残体95个，泥石流沟11条，变形体30个，冰碛体8个，堵江体11处，人工弃渣体1个，测年取样48个，现场筛析98个（室内96个），软弱剪切带强度试验样6个，在3个岩质露头获得了1794条结构面信息。.对高地应力河段高陡岸坡复杂结构岩体灾变地质过程机理与潜灾体分布规律在现场地质定性认识的前提下进行了深入的分析，定义了中晚更新世以来以>5mm/a速率隆升的河段为快速隆升河段的概念。总结金沙江上了典型河段纵向岭谷岸坡岩体结构以弯曲-拉裂模式为主，随河段走向与岩体结构的变化也发育了滑移-弯曲，滑移压致拉裂、蠕滑拉裂等模式。不乏成群连片分布的大型滑坡群，崩滑堵江残体。根据测年数据形成的年代均为晚更世的近150ka以来，根据西南江河河床普遍存在深厚覆盖层的特点，提出了快速隆升河段大型堆积体的成因受制于青藏高原快速隆升以及冰期海平面大幅度降低加速河谷下切速率的地球动力学系统双重致灾效应的观点。.在室内对复杂的岩体结构展开取样偏差校正与网络数值模拟，岩体结构等地质力学模型研究，探索致灾机理。对典型潜灾体特别是堵江进行了地震诱发堵江逆演与模拟的相关分析，典型岸段考虑人类活动条件下的风险性评估。..项目取得了如下主要成果，SCI收录论文38篇，EI收录论文18篇，专利6项，省部级二等奖2项，国际会议报告10个，国内会议邀请报告8个，6位博士生、3位硕士生受本项目资助获得学位。