大型顺层边坡稳定性分析方法及处治技术优化研究

发布时间：2018-07-04 11:47

本文选题：自定义本构 + 强度折减法　；参考：《北京科技大学》2015年博士论文

【摘要】：白云鄂博东矿是包钢乃至全国的主力稀土矿,随着开采高度的不断增加,滑塌事故屡屡发生,其中尤以B区滑体规模最大,且变形最为活跃。从已出露的边坡状态看,该区域边坡将长期处于多断层交叉影响带中,岩体极为破碎。而该区段恰恰是矿山开采和运输的咽喉通道,近年来已采取了一系列处治措施,各类加固工程受内部岩层错动影响已出现不同程度的变形。且随着深部边坡的开挖和各断层的交汇,该区域边坡会形成一个巨型潜在滑体,既有的处治方案能否保障深部边坡的安全,成为矿山亟待解决的重大技术难题。本研究以“白云鄂博铁矿边坡稳定性实时动态综合监测预警系统”项目为依托,以东矿边坡B区大型顺层边坡的典型剖面B-B’边坡为研究对象,针对现有岩质边坡稳定性分析及处治技术存在的问题,通过监测点的实测位移反演出适合B区工况的自定义本构模型,并基于此本构模型开展强度折减改进研究,获取更为可靠的边坡安全系数,最后针对性地提出边坡优化处治方案,主要包括以下研究工作： (1)基于广义非线性统一强度准则,以Visual C++编写广义非线性统一强度准则程序代码,通过调整中间应力参数b,生成不同的动态链接库文件并结合Flac3D的UDM(User Defined Model,自定义本构模型)功能,实现对不同非线性强度准则的数值模拟。 (2)基于BP神经网络反演技术,以监测点位移为输入向量,以各边坡岩体物理力学参数及中间应力参数b为输出向量,以多工况数值模拟样本构建BP神经网络系统。将现场实测位移代入该系统,反演得到适应本工况的岩体物理力学参数及中间应力参数b,完成基于广义非线性统一强度理论的自定义本构模型构建,经验证相比其他本构模型更符合本剖面边坡实际工况。 (3)从边坡极限状态下各岩体参数变化的差异性出发,合理设定不同参数的折减上下限,实现基于广义非线性统一强度准则的改进强度折减。并基于此改进折减方案,对边坡岩体进行稳定性评价研究,确定边坡岩体稳定性敏感度排序及关键岩体。 (4)基于本研究确定的自定义本构模型,对深部边坡按照既有处治措施进行开挖模拟,发现如深部边坡平台仍采取既有处治措施,极有可能发生大规模滑坡事故,必须采取进一步的处治措施。 (5)结合本研究得到的边坡岩体稳定性敏感度排序,确定了“锚固洞塞+注浆+预应力锚索+肋柱(锚墩)砼墙”的初步处治方案。经计算验证,采取初步处治方案后,可避免发生前文所述的大规模滑坡,但个别时期的边坡安全系数仍低于本研究剖面边坡的安全限值。为此,分别从“减少锚固洞塞爆破作业工作量”和“尽早提升断层破碎带岩体强度”两个角度,分析了对初步处治方案的优化机理,并针对性地提出了“锚固洞塞+系统布置型预应力锚索”和“超前注浆、整体锚固”的组合优化方案,经计算验证,优化后的方案取得了更好的加固效果,边坡处于更为稳定的状态。
[Abstract]:Baiyunebo east mine is the main Rare-earth Mine in Baotou Steel and even the whole country. With the continuous increase of the mining height, the collapse accidents occur repeatedly, especially the largest size of the slide body in the B area and the most active deformation. From the state of the exposed slope, the slope will be in the multi fault cross influence zone for a long time, and the rock mass is very broken. It is just the throat channel of mining and transportation. In recent years, a series of treatment measures have been taken. All kinds of reinforcement projects have been deformed in varying degrees under the influence of the internal rock strata, and with the excavation of the deep slope and the intersection of the faults, the slope of the region will form a giant potential slide, and the existing treatment scheme can guarantee the depth. The safety of the side slope has become a major technical problem to be solved in the mine.
Based on the project of "Baiyunebo iron mine slope stability real-time dynamic comprehensive monitoring and warning system", this study is based on the typical section B-B 'slope of the large bedding slope in the B area of the east mine slope as the research object. In view of the existing problems of the existing rock slope stability analysis and treatment technology, the measured displacement of the monitoring point is suitable for B. Based on this constitutive model, the strength reduction and improvement research is carried out to obtain a more reliable slope safety factor. Finally, the slope optimization treatment scheme is proposed, which mainly includes the following research work:
(1) based on the generalized nonlinear unified strength criterion, the program code of generalized nonlinear unified strength criterion is written in Visual C++. By adjusting the intermediate stress parameter B, different dynamic link library files are generated and the functions of Flac3D UDM (User Defined Model, custom constitutive model) are combined to realize the numerical simulation of different nonlinear strength criteria.
(2) based on the BP neural network inversion technique, the monitoring point displacement is the input vector, and the physical and mechanical parameters of the rock mass and the intermediate stress parameter B are the output vectors, and the BP neural network system is constructed by the numerical simulation samples of the multiple conditions. The field measured displacement is replaced by the system, and the physical and mechanical parameters of rock mass adapted to the working conditions and the middle part of the system are obtained. The stress parameter B is constructed by the custom constitutive model based on the generalized nonlinear unified strength theory. Compared with the other constitutive models, it is more consistent with the actual working conditions of the slope.
(3) starting from the difference of the variation of rock mass parameters under the limit state of the slope, the upper and lower limits of different parameters are set reasonably, and the improved strength reduction based on the generalized nonlinear unified strength criterion is realized. Based on this improved reduction scheme, the stability evaluation of slope rock mass is studied and the stability sensitivity of slope rock mass is sorted and closed. Bonded rock mass.
(4) based on the custom constitutive model determined by this study, the excavation simulation of the deep slope is carried out according to the existing treatment measures. It is found that the deep slope platform still takes the treatment measures, and it is extremely likely to take a large scale landslide accident, and further treatment measures must be taken.
(5) the preliminary treatment scheme of "anchorage plug + grouting + prestressed anchorage column (anchor pier) concrete wall" is determined according to the order of stability sensitivity of slope rock mass obtained in this study. After calculation and verification, a preliminary treatment scheme can be taken to avoid the large-scale landslides described in the previous article, but the safety factor of slope in some period is still lower than that of the research. This paper analyzes the optimization mechanism of the preliminary treatment scheme from two angles of "reducing the work load of anchorage plug blasting operation" and "improving the strength of rock mass as early as possible", and puts forward the "anchorage plug + system prestressed anchor cable" and "advance grouting". The combined optimization scheme of anchorage is verified by calculation. The optimized scheme has achieved better reinforcement effect and the slope is in a more stable state.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD854.6

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