缓倾厚层灰岩山体崩塌机理研究

Being a kind of catastrophic geological hazard, Collapse from sub-horizontally thick-bedded limestone mountain occurs frequently in southwestern China. The Mountain slope deformation induced by underground mining becomes an increasingly serious threat to local economy and inhabitants of southwestern mountainous area as human activities being on the rise. Under the circumstance, it is eager and necessary to carry out research on failure behavior and mechanism of collapse from sub-horizontally thick-bedded limestone mountain. The program will focuses on collapse from sub-horizontally thick-bedded limestone mountain in limestone covering area of south western China, such as Guizhou and Chongqing, which involves underground mining and deep fractures. And the author intends to analyze geological conditions, triggers and reasons so as to reveal response mechanism and consequent deformation law via multi-disciplinary methods. In order to study the evolution and failure behavior of collapse from sub-horizontally thick-bedded limestone mountain, numerical simulation and centrifuge modeling would be conducted to reproduce initiation and failure process on the basis of laboratory tests. The outputs are expected to improve mechanism study on collapse from sub-horizontally thick-bedded limestone mountain, and provide some new thoughts for hazards mitigation in mining area.

缓倾厚层灰岩山体崩塌是我国西南地区最为频发的一种地质灾害类型。随着人类工程活动的日益频繁，地下采空区的缓倾厚层灰岩崩塌的危害性日益严重，已成为制约西南灰岩山区经济发展和人居安全的重大灾害隐患，因此开展此类崩塌灾害成灾机理和破坏模式研究十分迫切和必要。本项目通过多学科联合手段，研究黔渝等地区缓倾厚层灰岩山体崩塌形成的地质环境条件、诱发因素和成因机制，研究地下采空和深大裂隙作用下缓倾山体崩塌灾害的响应机理和变形规律；通过力学试验、数值模拟与离心物理模型试验，再现缓倾厚层灰岩山体崩塌初始变形破坏过程和后破坏-崩塌过程，研究其变形演化过程和失稳模式；利用极限平衡等数学解析，提出其稳定性评价分析方法，为西南山区地下采空区的崩塌灾害减灾防灾提供技术支撑。研究成果将把缓倾厚层灰岩山体崩塌研究推向一个新台阶，并为西南山区矿区崩塌灾害防治提供新思路，具有一定的科学与社会意义。

缓倾厚层高陡山体破坏以塔柱状危岩崩塌为主，其破坏方式多呈现出“受压损伤—压裂溃屈—整体崩解”的破坏特征。本项目在现场调查与特征分析基础上，采用工程地质分析、运动学解析、数值模拟等技术方法，运用损伤力学理论，系统分析了缓倾厚层高陡山体塔柱状危岩压裂溃屈崩塌破坏机理。.①以三处典型重大崩塌灾害为例，分析了灰岩山区缓倾厚层高陡危岩变形破坏特征，根据岩体受力状态、变形破坏规律及裂隙结构面的发展规律，提出了相应的崩塌失稳模式和工程地质识别指标。.②利用影像解析方法研究了缓倾厚层山体塔柱状危岩崩塌灾变过程的动力学特征，将塔柱状危岩压裂溃屈崩塌初始失稳划分为低速启动-加速破坏-减速碰撞三个运动阶段，失稳从底部岩体溃屈破坏开始，呈现出由下至上、裂缝扩展、破坏传递、空中崩解的特点。.③基于连续介质损伤力学理论，分析了缓倾厚层山体塔柱状危岩底部岩体损伤演化过程，从损伤力学角度解释塔柱状底部岩体的强度劣化机制，建立了随损伤演化的塔柱状危岩稳定性计算分析方法。.④利用有限差分数值模拟方法分析长期自重作用、地下采空对缓倾厚层山体塔柱状危岩变形破坏特征与稳定性的影响，模拟结果表明底部岩体裂化是导致塔柱状危岩发生压裂溃屈崩塌的直接原因。.⑤离心模型试验重现了缓倾厚层山体塔柱状危岩体底部压裂、上部座落崩塌的破坏机制，试验结果表明地下采空会导致陡崖危岩变形加速、变形加剧。