考虑到岩体尺寸效应的深凹岩石边坡角的确定

以喇叭形曲面边坡上环岩体为力学模型 ,分析其临界下滑时的应力状态 ,以库仑准则作为环岩体的破坏准则 ,并考虑到环岩体的尺寸效应 ,推导出了深凹边坡的临界稳定性坡角与岩体的物理参数 ,及边坡水平半径之间的关系式。该式反应了深凹边坡的稳定性坡角可随着开挖深度增加而增大的规律 ,为采用减少深凹露天矿底部废石剥离量的凸曲线形边坡奠定了理论基础 ,也为确定其边坡的合理形状提供了基本方法     

Comprehensive analysis of slope stability and determination of stable slopes in the Chador-Malu iron ore mine using numerical and limit equilibrium methods

One of the critical aspects in mine design is slope stability analysis and the determination of stable slopes. In the Chador Malu iron ore mine, one of the most important iron ore mines in central Iran, it was considered vital to perform a comprehensive slope stability analysis. At first, we divided the existing rock hosting pit into six zones and a geotechnical map was prepared. Then,the value of MRMR (Mining Rock Mass Rating) was determined for each zone. Owing to the fact that the Chador-Malu iron ore mine is located in a highly tectonic area and the rock mass completely crushed, the Hock-Brown failure criterion was found suitable to estimate geo-mechanical parameters. After that, the value of cohesion (c) and friction angle (e) were calculated for different geotechnical zones and relative graphs and equations were derived as a function of slope height. The stability analyses using numerical and limit equilibrium methods showed that some instability problems might occur by increasing the slope height.Therefore, stable slopes for each geotechnical zone and prepared sections were calculated and presented as a function of slope height.     

大冶铁矿东露天采场边坡破坏判据的研究

通过对大冶铁矿东露天采场F9,F13断裂带内边坡的深入研究,从整体与局部稳定性系数等方面探讨了边坡破坏判据．利用有限元强度折减法和极限平衡法计算边坡的体稳定性,得出边坡处于极限平衡状态时的塑性应力及塑性应变,提出边坡破坏判据．     

Effect of rock mass structure and block size on the slope stability--Physical modeling and discrete element simulation

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.     

Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

Rock slope has many geological structures with different sizes, configurations and mechanical properties such as joints, fissures, faults, shear bands and so on[1]. These geological structures may make the slope unstable, producing toppling, fracturing or sliding failures. A lot of investigations have focused on the stability of jointed rock slope, however, the mechanisms on the progressive failure of jointed rock slope is still an open issue in either physical modeling or numerical simulation…     

基于强度折减法的不同坡角边坡稳定性分析

介绍了强度折减法的基本原理,在此基础上运用强度折减法分析边坡坡角对边坡稳定性的影响,运用ANSYS软件模拟不同坡角的边坡,分析计算不同坡角边坡的安全系数,通过计算得出不同坡角边坡围岩极限破坏时的折减强度参数,分析研究边坡坡角与边坡安全系数F、边坡围岩极限破坏凝聚力c’及极限破坏摩擦角‘φ’之间的关系。     

不同含石率及基覆岩层倾角下土石混合体边坡稳定性分析

为准确地分析土石混合体边坡的稳定性，提出了一种可考虑不同块石含量、块石随机分布及基覆岩层倾角的边坡稳定性分析方法。该方法根据土石混合体边坡中的块石含量、级配以及基覆岩层倾角，随机生成了含石率从10%～60%、基覆岩层倾角从0°～20°的边坡模型，每种含石率及基覆岩层倾角均考虑8个不同的块石分布位置，最后将生成的模型导入到Optum G2中建立土石混合体边坡模型，采用有限元极限分析法对该类型边坡的稳定性进行了分析，并将计算结果与采用Kalender等效强度参数模型所得的结果进行了对比验证。研究结果表明，由于块石空间分布位置的不同，相同含石率及基覆岩层倾角下土石混合体边坡的最大、最小下、上限安全系数变化较大；相同含石率下，随着基覆岩层倾角的增加，边坡的下、上限安全系数的平均值变化相对较小；土石混合体边坡坡体中的剪切带呈现出“绕石”、“分流”以及“包含”这3种典型的扩展模式；通过将本文方法与Kalender等效强度参数模型所得的安全系数进行的对比分析，验证了作者所提方法的可行性。研究结果可为土石混合体边坡的设计及施工提供参考依据。     

福建高速公路边坡岩土体质量评价方法

福建省高速公路边坡上部为土下部为岩,整体稳定状态良好,为对在开挖后及支护前后出现局部滑塌现象的岩土边坡进行快速、准确的稳定性评价,基于极限平衡法,提出一种适合于岩土边坡岩土体质量评价的方法,首次综合岩和土的质量评价方法对边坡稳定性进行分析,扩充了边坡岩体分级的范畴．用该法评价福建省7条高速公路的102个边坡,结果与实际...     

基于未确知测度理论的基坑边坡稳定性评价

影响基坑边坡稳定的不确定性因素较多,如基坑规模、场地岩土体性质、施工质量、环境因素等。为了探索科学合理的基坑边坡的稳定性评价方法,本文基于未确知测度理论,选取了基坑深度、支护方式、主要土层粘聚力、主要土层内摩擦角、地下水及地表水作用、邻近荷载、邻近荷载坑边距、施工质量八个因素作为评价指标,利用三标度法结合层次分析法确定各指标权重,建立基坑边坡稳定性评价模型。将此模型应用于两个基坑工程实例,对比实际监测结果,评价结果的可靠度较高。结果表明,基于未确知测度理论的基坑边坡稳定性评价模型具有可行性。     

基于可靠性的复合土钉支护基坑稳定性分析

针对预应力锚杆复合土钉支护基坑内部整体稳定的可靠性计算问题,以边坡极限平衡理论与圆弧滑动面法为基础,应用扰动力法建立了基坑内部整体稳定性分析的功能函数与最危险滑动面的计算模型.通过SLP优化法与单形调优法实现了最危险滑动面的优化搜索.以土体的抗剪强度指标作为随机变量,应用AFOSM(2)法计算了基坑内部整体稳定可靠性指...     

Stability and reinforcement analysis of rock slope based on elasto-plastic finite element method

The rigid body limit equilibrium method(RBLEM) and finite element method(FEM) are two widely used approaches for rock slope's stability analysis currently. RBLEM introduced plethoric assumptions; while traditional FEM relied on artificial factors when determining factor of safety(FOS) and sliding surfaces. Based on the definition of structure instability that an elasto-plastic structure is not stable if it is unable to satisfy simultaneously equilibrium condition, kinematical admissibility and constitutive equations under given external loads, deformation reinforcement theory(DRT) is developed. With this theory, plastic complementary energy(PCE) can be used to evaluate the overall stability of rock slope, and the unbalanced force beyond the yield surface could be the identification of local failure. Compared with traditional slope stability analysis approaches, the PCE norm curve to strength reduced factor is introduced and the unbalanced force is applied to the determination of key sliding surfaces and required reinforcement. Typical and important issues in rock slope stability are tested in TFINE(a three-dimensional nonlinear finite element program), which is further applied to several representatives of high rock slope's stability evaluation and reinforcement engineering practice in southwest of China.     

Space-time principles of reducing stripping in furrow pits

The lower slope of furrow pits has following special features: small extent of weathering destruction, short time of production blasting damage, good arching effect of lower slope with small curvature radius, and good bottom effect of a pit end for transferring and bearing initial horizontal stresses in lower slope. The new principles provided theoretical basis for convex slope in furrow pits to reduce stripping. Similar phenomena and examples are supplied simultaneously.     

Stability and reliability of pit slopes in surface mining combined with underground mining in Tonglushan mine

Slope stability is of critical importance in the process of surface-underground mining combination. The influence of underground mining on pit slope stability was mainly discussed, and the self-stabilization of underground stopes was also studied. The random finite element method was used to analyze the probability of the rock mass stability degree of both pit slopes and underground stopes. Meanwhile, 3D elasto-plastic finite element method was used to research into the stress, strain and rock mass failure resulting from mining. The results of numerical simulation indicate that the mining of the underground test stope has certain influence on the stability of the pit slope, but the influence is not great. The safety factor of pit slope is decreased by 0.06, and the failure probability of the pit slope is increased by 1.84%. In addition, the strata yielding zone exists around the underground test stope. The results basically conform to the information coming from the field monitoring.     

Probabilistic approach for open pit bench slope stability analysis——A mine case study

The geotechnical slope design of an open pit wall starts at the bench scale configuration. At this scale, the rock slope stability is governed primarily by the geological discontinuities within the rock mass and as a result, structurally-controlled failures(e.g. planar, wedge or toppling) are most likely to occur. The probabilistic approach offers a major advantage over the traditional deterministic method in that it accounts for the different degrees of variability and uncertainty often encountered in rock properties. This paper presents a bench slope stability assessment for an open pit mine in Peru using a probabilistic-based approach by coupling a kinematic analysis based on stereographic projection techniques followed by a kinetic analysis by means of the limit equilibrium method. Finally, these two probabilities are combined to provide an overall measure of the probability of failure(PoF) of the bench slope system. The case study is characterized by significant scatter in the geometrical and mechanical properties of the joints.Extensive surface mapping was conducted at 36 different sites following the ISRM suggested procedures.Several direct shear tests were carried out. It is shown that by combining field and laboratory measurements and engineering judgment, the probability density functions(PDF) of the discontinuity parameters can be obtained. These are then used in a Monte Carlo simulation process to compute both kinematic and kinetic probabilities of failure. The overall probability of failure aims to provide the design engineer with a tool to critically evaluate the bench performance from a geotechnical risk perspective and to provide a basis for future bench design optimization.     

大空间建筑环形点式重载作用下深废矿坑岩壁变形稳定性数值分析

近年来,大城市工程建设急速发展,土地资源愈发紧张,一些矿产资源型城市中出现了利用废弃天然矿坑进行地下空间开发的改造项目。以长沙湘江欢乐城项目深废矿坑改造开发工程为背景,针对矿坑边坡稳定性以及受建筑结构点式荷载作用下的岩壁与基础协同作用问题,利用数值分析手段建立三维岩壁-建筑结构相互作用模型。研究岩壁在环形点式受荷条件下的表现,并探究遭遇突发性岩壁变形及承载状态变化后,岩壁与结构的稳定性变化情况。结果表明,在天然状况下废弃矿坑的开采高边坡基本处于稳定状态;而施工扰动和建筑荷载造成的应力变形仅发生于岩壁表面,未达岩体深部;岩壁由于突发灾害产生的局部大变形会严重危及支承其上的基础和结构安全;而在合理的建筑物环形点式基础设计布置情况下,基础结构的偶然失效不会影响岩壁和建筑物的稳定性。     

边坡稳定问题的算法比较

文章利用边坡稳定分析的应力状态新方法中的一系列公式,与泰勒稳定系数法以及Fellenius条分法,在极限状态和稳定状态计算与新方法的比较,并说明了系列公式的实用性。     

单纯形替换最优化方法在霍各乞铜矿边坡稳定性分析中的应用

当边坡内没有明显的断裂面控制边坡的破坏时，应用极限平衡方法计算边坡安全系数需要确定具有最小安全系数的滑面，边坡安全系数是可能滑面的函数，而只有最小安全系数才可代表边坡的安全程度，用最优化理论中的单纯形替换法对霍各乞铜矿边坡的最小安全系数和相应最危险滑面进行了分析与研究，为边坡的设计提供决策的依据。     

阿海水电站左岸开挖边坡稳定性分析研究

在水电站建设中,由于开挖而形成的一些高边坡,其稳定性状态是影响水电站建设能否顺利进行的关键问题之一.阿海水电站工程地质条件复杂,针对左岸开挖形成的岩质边坡,考虑了不同水位变化、地震、降雨等,对其典型边坡进行稳定性分析研究.采用极限平衡法定量分析了各种工况下的安全程度,同时使用有限元强度折减法进行了应力变形和稳定性分析.在此基础上,提出了对应的边坡治理措施,为阿海水电站的边坡治理提供理论参考.     

临河岩质边坡地震抗倾覆稳定性拟动力分析

基于拟动力法推导出不同工况条件下临河岩质边坡地震抗倾覆稳定安全系数计算公式。通过参数分析,研究不同岩体放大系数下,水平和垂直地震力、张裂缝积水深度、边坡超载、锚固效应、流水淘蚀等对岩质边坡地震抗倾覆稳定性的影响,研究表明,不同工况下,张裂缝积水深度、水平地震力、流水淘蚀不利于岩质边坡地震抗倾覆稳定,但竖向地震力、锚固力、锚固高度、坡顶超载等有利于岩质边坡地震抗倾覆稳定;随着岩体放大系数的增加,水平地震力、竖向地震力对岩质边坡抗倾覆稳定性的影响增大,坡顶超载、张裂缝积水深度、锚固应力、锚固高度、临河水位对岩质边坡抗倾覆稳定性的影响减小,而锚固倾角、坡脚淘蚀高度对边坡抗倾覆稳定性的影响基本不变。     

基于随机场的岩石边坡三维稳定性分析

基于随机场理论,考虑了岩石材料属性的空间变异性对岩石边坡稳定性的影响,将边坡主滑面上的摩擦系数和粘聚力视为高斯随机变量,确定了主滑面上的摩擦系数和粘聚力的均值、方差和协方差,获得了两个随机量之间的相关系数和互相关长度。在此基础上,对岩石边坡进行了三维稳定性分析,确定了岩石边坡的稳定系数和失效概率。数值计算结果表明,摩擦系数和粘聚力的空间变异性对边坡稳定性有重要影响。