地下采煤引发黄土滑坡的形成机理研究

Loess area is rich in coal resources. Surface subsidence produced by underground mining superimposed on the original loess slope, the loess slope became steeper. Due to an increase in fractures, strength of loess is reduced. Landslide disaster triggered by underground mining seriously affected people's lives and property of surface and underground mining safety. So the research on landslide disaster triggered by underground mining is very important and urgent. The project study will take the underground coal mining triggered loess landslides as the core, the research highlights include the stress change in slope caused by surface deformation and loess strength deterioration caused by loess fracture because of underground mining. Research methods include data collection and analysis, field survey, three-dimensional laser scanning surveying, exploration, monitoring, laboratory tests, physical model tests, centrifuge model tests and numerical simulation. Through the efforts of research, expect to identify the formation mechanism of loess landslides triggered by underground coal mining, and propose a new forecasting method of landslide based on surface movement monitoring.

黄土地区储藏有丰富的煤炭资源。地下采煤产生的地表塌陷，叠加在原始黄土斜坡之上，使得坡度变陡，黄土发生裂隙化而使其强度降低，从而容易引发滑坡灾害，严重影响了地表人民生命财产安全和地下采矿安全，因此专门开展采煤引发的滑坡研究迫在眉睫。本项目以地下采煤引发黄土滑坡的形成机理为研究主线，以地下采煤导致地表形变引起斜坡内应力变化和黄土体裂隙化导致黄土强度的劣化为主要研究内容，以资料收集分析、现场调查、三维激光扫描、测绘、勘探、监测、室内试验、物理模型试验、离心模型试验和数值模拟为研究方法。通过项目研究，期望能够查明地下采煤引发黄土滑坡的形成机理，提出基于地表移动监测的矿区滑坡预测方法。

黄土地区储藏有丰富的煤炭资源。地下采煤产生的地表塌陷叠加在原始黄土斜坡之上，容易引发滑坡灾害，严重影响了地表人民生命财产安全和地下采矿安全，因此该项目专门开展了地下采煤引发黄土滑坡的形成机理研究，研究成果丰富了滑坡理论，同时可为黄土地区煤矿地质灾害防控提供理论指导。.项目重点对彬长矿区和黄陵矿区的地下采煤引发的地表形变和滑坡灾害进行了较为详细的资料收集和野外调查测绘，查明了地下采煤对地表黄土斜坡的影响及其与滑坡灾害的相关关系。测试了黄土的物理力学性质，提取了黄土塬边黄土物理力学性质参数，建立了可供定量分析的地下采煤引发黄土滑坡工程地质结构模型。.基于模型试验、室内试验和理论分析，查明了地下采煤导致黄土斜坡裂隙化规律和裂隙化导致黄土强度劣化规律。得出裂隙扩展具有明显序次和空间分异特征，可分为与坡面近垂直裂隙和与坡面近平行裂隙两组。前者随着地下采煤塌陷扩展速度快，范围广，密度大，具有拉张裂隙的特征，宽度较宽，裂隙两壁参差不齐；后者为前者派生裂隙，且集中在坡体内部，密度较小，具有剪切裂隙的显著特征，裂隙比较紧闭，局部呈羽列状。黄土内摩擦角随着裂隙密度的增加明显减小。粘聚力在低含水率下亦呈减小趋势。内摩擦角随着裂隙面和最大剪应力面夹角大小的增大而增大。裂隙粘聚力与裂隙产状相关性不明显。.基于离心实验、数值模拟和理论分析，对地下采煤引发黄土滑坡的形成机理进行了深入探讨。地下采煤引起的岩土体不均匀形变传递到黄土斜坡，导致斜坡中出现了与坡面近垂直裂隙。与坡面近垂直裂隙不仅仅降低了斜坡的完整性，降低了土体的强度，还使得斜坡的应力状态发生重新分布，派生出与坡面近平行裂隙。随着地下采煤的推进，与坡面近平行裂隙会逐步贯通进而形成滑坡滑面。