【作者】 杜俊；

【导师】 侯克鹏；

【作者基本信息】 昆明理工大学 ， 地质工程， 2014， 博士

【摘要】 层状边坡由于岩体结构的成层特性,其破坏机理与失稳模式也有别于其它岩质边坡。尖山磷矿层状边坡在过往采矿活动中,受工程开挖扰动及外营力作用影响,于不同开采阶段表现出不同程度的变形破坏,边坡稳定性已成为矿山潜在的安全隐患。本文以尖山磷矿层状边坡为研究对象,重视露天矿开采技术条件及边坡岩体力学特性分析,结合工程岩体稳定性分析、边坡动力演化试验和数值分析方法对边坡开挖变形破坏机理与失稳模式开展深入研究,并提出相应的边坡稳定性控制对策。通过现场调查、理论分析和试验研究,主要取得如下研究成果：(1)结合尖山磷矿露天开采技术条件,划分工程边坡岩体,采用测线法对工程岩体随机结构面性状进行分析,指出影响边坡稳定的岩体优势结构面所在。在研究区工程岩体质量分级的基础上,采用岩体声波测试技术和岩体块度指标RBI对工程岩体完整性及结构特征进行评价,并由此确定了边坡保留岩体的扰动范围与扰动系数D值。借助广义Hoek-Brown强度准则估算边坡岩体力学参数,并对边坡关键岩体进行现场原位直剪试验,综合确定了边坡宏观岩体力学参数。(2)基于层状边坡工程分类特征,分析了不同坡体结构与岩性组合特征的层状边坡变形机理和潜在失稳模式。从边坡应力状态和变形演化过程描述研究区边坡滑移-弯曲-剪切变形破坏模式,边坡潜在的滑动面表征出上部为“平面”下部为“圆弧面”的平面复合形态。(3)分析研究了层状边坡滑移弯曲破坏的受力机制,并对边坡岩体变形的非线性特征,采用系统科学中的突变理论建立了层状岩板结构系统的尖点突变模型,再现了作用力渐变导致边坡系统状态突变的灾变过程。(4)基于研究区边坡赋存的地质环境条件,采用物理模型试验技术,建立了岩层倾角四十五度、五十度“一面坡”开挖模型与岩层倾角变化开挖模型,通过对开挖边坡位移变化与位移矢量场变化特征进行分析,研究区边坡开挖变形破坏模式为上部岩体顺层滑移,中下部岩体受滑移挤压产生弯曲变形,当变形程度超过岩体极限承载能力时,边坡易沿弯曲变形曲率最大的路径发生剪切破坏,潜在滑动面为上部平行临空面的滑移面,下部类似圆弧的剪切面。(5)对尖山磷矿层状边坡进行开挖数值分析,开挖边坡引起边坡岩体应力重新分布,坡面岩体出现了新的“应力平衡区域”,并且激活了原有被控制的对边坡稳定不利的因素,开挖面岩体应力的松弛和岩体中应力场的变化致使岩体产生变形。开挖边坡使得岩层间阻滑力减小,层间相对运动增大,边坡上部岩体沿层面呈现向下滑动趋势,边坡下部岩体受上部岩体挤压作用产生侧向临空面的弯曲变形,受坡体内发育的结构面切割作用,弯曲变形岩体异常破碎,利于剪切面贯通扩展,边坡滑移面与剪切面完全贯通,使得整体边坡出现滑移-弯曲-剪切破坏,边坡滑动面是上部近似平面与下部类似圆弧剪切面的组合。(6)依据矿山深部开采技术条件,提出对尖山磷矿边坡进行“顶部卸载、坑底内排”的控稳对策,实现矿山安全、高效的生产。更多还原

【Abstract】 Because of the layered characteristics of rock structure, the failure mechanism and instability mode of layered slope is different from other slope. In the past mining activities, affected by engineering excavation disturbance and exogenic force, Jianshan phosphate rock slopes show different degrees of deformation and failure in different mining stages, slope stability has become a potential safety hazards in mines. In this paper, taking Jianshan phosphate layered slope as the object of study, paying attention to open-pit mining technology condition and analysis of mechanical properties of rock mass, combined with the analysis of the stability of engineering rock mass, the slope dynamic evolution test and numerical analysis method to carry out an in-depth study on slope deformation and failure mechanism and instability mode, and puts forward the countermeasures to control the stability of slope. Through field investigation, theoretical analysis and experimental study, the main research results obtained are as follows:(1) Combined with conditions of Jianshan open-pit mine, divide the rock mass, analyze random structure surface characters on engineering rock mass by use of the survey line, point out position of dominant structural plane of rock mass that affects on slope stability. Based on the classification of engineering rock mass, evaluate integrity and structural characteristics of engineering rock mass through testing technique on rock sonic wave and rock block index RBI, determine the range of disturbance of the reserved slope rock and coefficient of disturbance D. With the help of the generalized Hoek-Brown criterion to estimate the mechanical parameters of rock slope, carry out the in-situ direct shear testing on the key rock slope, comprehensively determine the macroscopic rock mechanics parameters of slope.(2) Based on classification feature of the layered slope engineering, analyze the deformation mechanism of layered slope and potential failure mode of different slope structures and lithologic features. Analyze the stress state of the slope rock mass and evolution, deformation mode of layered slope on Jianshan phosphate rock is slip-bending-shear failure, and the potential sliding surface is a combination that upper part is plane and lower part is arc surface.(3) Analyze sliding-bending stress mechanism of layered slope, aiming at the nonlinear characteristic of deformation of slope rock mass, apply catastrophe theory in systems science to disaster analysis of buckling deformation of layered slope, build the cusp catastrophe model of layered rock board system, reproduce the catastrophe process of gradient force leading to mutation of system state of the slope.(4) Based on geological environment of slope in studying area, use the technique of physical model test,build slope excavation model with dip angle45or50in side slope and excavation model with changeable dip angle, combined with analysis on slope displacement and variation of displacement vector field. The deformation and failure mode of slope excavation is that upper body is bedding slip, lower body produces bending deformation with slip and extrusion. When the deformation exceeds the limit bearing capacity of rock, the slope tends to destruct along the path with the bending deformation of maximum curvature, the potential sliding surface is that upper slip surface is parallel to the free surface, lower shear plane is similar to arc.(5) Numerically analyze open-pit mining of Jianshan layered slope, excavation of slope leads to redistribution of stress in rock mass, the slope emergence a new "stress balance area", and activate the original control on slope stability of adverse factors, relaxation from the excavation of rock stress and change of stress field in rock mass result in deformation. The excavation of rock slope makes resistance between the sliding force decreasing, the relative movement between the layers increasing. The upper part of slope rock mass tends to sliding downward along the level, the lower part of the slope with the extrusion from the upper produces bending deformation from lateral free surface, cutted by developed structural surfaces, rock mass with bending deformation is anomaly broken, which is beneficial to that the shear plane goes through completely. Slip surface and the shear plane of slope is fully connected, makes the overall slope produce slip-bending-shear failure, slope slip surface is a combination with upper slip surface parallel to the free surface, lower shear plane similar to arc.(6) On the basis of the mining condition in the deep, propose the stability controlling countermeasures of top unloading, bottom dumping in on Jianshan phosphate rock slope, realize safe, efficient production of mine.更多还原