高陡边坡整体与局部失稳的强度折减及安全度判别分析

为了实现从整体和局部都能较为准确地分析弧状高陡边坡安全稳定性,指导露天采矿高陡边坡设计,采用有限差分强度折减法分析边坡稳定性,获得边坡整体的安全系数。对每个计算单元引入安全度进行分析,获得边坡局部安全系数;将最大节点位移时步曲线收敛性作为边坡失稳的判定准则,弥补了采用其他准则时由于人为指定容差而引起的较大误差;以某铁矿西南边坡为例,运用FISH语言编制强度折减法、失稳准则和安全度相关程序进行计算。研究表明：有限差分强度折减法、基于最大节点位移时步曲线收敛性的失稳准则和计算单元安全度相结合的边坡稳定性分析方法适合于弧状边坡稳定性分析,研究为弧状高陡边坡设计提出了新的思路。     

Study on high and steep slope stability Based on 3D laser scanning

Dangerous mountain construction projects block of high and steep slope stability is the important issue of security and disaster prevention, investigation on the surface of the dangerous mountain high and steep slope rock mass structure is the key to the analysis of the problem. The high slope of a major project of the Lancang River, the application of 3D laser scanning technique to study the long-distance survey analysis of rock mass structure analysis method to analyze the distribution of the surface space of the high and steep slope rock mass structure, statistical analysis direction of the advantages of the structure surface and the distribution of rock blocks, as the basis for the application of limit equilibrium analysis method to study the stability of rock blocks of the high and steep slope.     

Rainfall''s Effect on the Stability of Unsaturated Slopes

Aimed to analyze the influence of rainfall on slope stability. The finite element method (FEM) is used for the calculation of 2-D transient seepage in the unsaturated slope, while the method of limit equilibrium is used for computing its safety factor. The change of pore water pressure, slip surface and safety factor are investigated through numerical calculations with consideration of various intensity and duration of rainfall. Special attention has been paid to slope stability after rainfall. It is found that sometimes the minimum safety factor may occur several hours or several days after the rainfall, instead of the time during the rainfall or when the rain just stops.     

不同失稳判据下边坡稳定性的规律性

以塑性区贯通、位移增量突变、计算不收敛3种边坡失稳判据为依据,采用强度折减有限元法和重度增加有限元法对简单边坡进行了分析。结果表明：以边坡潜在滑动面上某点位移增量突变作为边坡失稳判据是准确的;对于不同土体强度参数下,以位移增量关系曲线突变为判据得到的边坡的安全系数较另外两种方法稳定;对应于塑性区贯通、位移增量曲线突变和计算不收敛的3种判据,边坡潜在滑动面依次向深层发展,边坡的安全系数依次增加。     

Mechanical properties and numerical simulation of unloading of brittle rocks under high geostress

The investigations on the deformation mechanisms, estimation of stability and technique of disasters controlled of brittle rocks excavated under high geostress are difficult points for rock mechanics and engineering geology. The evolutionary rule of mechanical parameters and deformation failure of brittle rocks are discussed based on unloading under high geostress, and the obvious characteristics of strain strength for brittle rocks under high geostress is found. It is presented that the brittle rock yielded follows Griffith rule of strain strength at peak. The elasto brittle plastic numerical calculation method is established considering the dynamical variation of mechanical parameters in course of unloading yield, and it is validated by practical engineering.     

Couple Analysis of the Slice and Gravity Increasing Methods of Slope Stability

The finite element or finite difference method and the limit equilibrium method, with their respective merits, were used to analyze soil slope stability in detail. On the basis of the slice and gravity increase methods, a fundamental principle of couple analysis, and a procedure for calculating the slope safety factor were put forward. ANSYS finite element software and finite difference software FLAC were used to determine the most dangerous sliding face and the stress-stain in slopes. The slope safety factor was determined using the slices limit equilibrium method. The calculation shows that the result obtained using couple analysis is close to the results produced using other methods in the example, and the analysis of the effects of the intensity indices is more precise. The results can provide a basis for consolidating design of the sliding slope.     

考虑渗流和地震时的砂土边坡稳定性计算

基于极限平衡理论,以砂土边坡为研究对象,推导了渗流和地震存在时拟静力法和拟动力法边坡安全系数的计算表达式。通过程序求解,与已有算例对比表明,计算结果基本一致,验证了2种方法解析式的合理性。参数分析表明,水位越高,边坡失稳越严重,水力梯度与安全系数基本为线性关系。渗流方向向下时,稳定性随水力梯度的增加而增大;渗流方向向上时,变化规律相反。水平地震加速度系数对稳定性的影响剧烈,竖向地震加速度系数对稳定性影响较小,简化计算可以忽略不计。最终得出拟静力法的解析式,简单、实用,而拟动力法则可以更为全面地考察砂土边坡稳定性随时间变化的特点。     

The Recent Progress of the Slope Stability Analysis Methods

The slope stability is an important research content in rock mechanics. In recent years, the great achievement has been gained for the slope stability analysis methods. The deterministic analysis methods, including limit equilibrium theory, numerical analysis method, graphic method and compound method, have been developed. The stochastic analysis method and the fuzzy analysis method come forward. The recent progress of the slope stability analysis methods is analyzed in this paper. The trend of progress of the slope stability is studied.     

Research on Evaluation of the Slope Stability Based on the Extension Theory

The stability of rock-mass slopes is a very complicated system which is controlled by lots of factors. It is always a very important research subject to evaluate the slope stability reasonably through some evaluation methods. Based on matter-element theory and dependent function,the extension theory is applied to evaluate the stability of rock mass slope,and the extension method for the stability of rock mass slopes is proposed. Taking a real slope project for example,based on the reasonable selection of evaluation factors of slope stability,an extension model for evaluation of slope stability is built,whose result is contrasted with the fuzzy evaluating one. As a result, it is practical and feasible to apply the extension method to estimate the rock slope stability.     

农业灌溉作用下黄土边坡失稳引起耕地流失分析

为了明确在大面积农业灌溉作用下，水分入渗土壤进而渗入下部黄土体，改变临空耕地黄土边坡的稳定性状态，造成边坡失稳引起耕地流失的过程。在统计分析甘肃天水耕地流失面积、农田灌溉面积、地质灾害数量和由地质灾害造成耕地流失比例的基础上，在典型地层剖面上采集原状土壤和黄土试样，进行天然状态和灌溉作用下土体的物理力学性质和抗剪强度试验，采用理正岩土边坡稳定性分析系统，利用基于极限平衡条分法的瑞典法进行边坡稳定性定量分析。结果表明：在天然状态下，该边坡稳定性系数为1.074，处于基本稳定状态；而在灌溉作用下，随着水分入渗深度的增加，稳定性系数逐步降低，最后失稳。因农田灌溉仅使土壤层饱和，对该边坡稳定性影响不大；当灌溉水持续入渗使饱和层土体厚度大于2 m时，该边坡稳定性降低一个等级，处欠稳定状态；当饱和层厚度大于10 m时，该边坡失稳，发生滑坡，造成耕地流失。     

Experimental Study on the Characteristic of Seepage with Unloading Rock Mass

The destruction of rock mass arises from opening rock possibly, the main outside-factor of influence rock slope stability is groundwater and water seepage. To analyze the relationship of unloading and permeability coefficient, the method and step of experiment of unloading rock mass are put forward. The curve relationship of the seepage-unloading of different phase is found by experiment. According to the experimental result, the equation of the seepage-stress of unloading is established, the variational rule of the unloading and permeability coefficient is discussed. The permeability coefficient is almost unchanged in the elasticity phase of unloading process. The permeability coefficient changes very much in the plastic phase of unloading process, as the unloading is 80% of ultimate unloading especially, and the permeability coefficient is increasing very much.     

Dynamic Influence of Sustained Small Rainfall Infiltration on Stability of Unsaturated Soil Slope

Taking the moisture content as main control parameter of shear strength of the soil, we analyze the variational properties of moisture content and shear strength with the change of rainfall time during the small sustained rainfall infiltration, and establish the relationships between total cohesion as well as effective angle of friction and the time of sustained small rainfall infiltration into an unsaturated slope. With the rainfall infiltration, the influence area of slope expands. Through the strength reduction method based on FLAC3D, the dynamic safety factor of slope in different time and the duration time before the failure of the slope are obtained. The results show that the slope critical sliding surface is yet unsaturated during a sustained small rainfall.     

Study on Cusp Catastrophe Mutation of Slope Destability

A complete theoretical model for slope destabilizing mutation has been set up by studying the geomechanical model and the influences of all circumstantial factors on slope stability,and by applying nonlinear theory.This paper analyzed the influence of controlled variables in the mutation model on the slope in causing slow or fast creeping.As the limit equilibrium stability analysis method of rigid bodies has some defects in slope stability assessment,the new theory of rigidity destabilization is helpful in forming criteria for judging slope creep destabilization.This analysis explains well the underlying causes of creeping slope destabilization and proves the feasibility of studying slope creep with a mutation model.     

土体抗剪强度指标变异水平对边坡稳定安全系数取值的影响

针对传统的边坡稳定极限平衡方法不能考虑土体抗剪强度指标变异性影响的问题,基于极限状态的概率分析原理,采用Monte-Carlo法对均质路堤边坡的稳定性开展了可靠度计算,讨论了稳定安全系数一定的条件下边坡失效概率随土体抗剪强度指标变异水平的变化规律,分析了安全系数与边坡可靠指标的对应关系及其随土体抗剪强度指标变异水平的变化特征。研究表明：边坡可靠度受土体抗剪强度指标变异性影响显著,呈现出随土体抗剪强度指标变异水平提高而急剧减小的趋势;为保证边坡具有相同的可靠性,安全系数的取值应与土体抗剪强度指标的变异性相适应,据此提出了基于可靠指标和土体抗剪强度指标变异水平的安全系数取值原则及其对应的三参数函数关系式。     

Application of Coordinate Difference Method in Safe Monitor of High Slope with Total Station Actively

The most common used method for safe monitor of high slope is to set a fixed observation point to monitor the transformation. But in urban area, due to restriction of the site and telecommunication conditions the transformation of high slope may have an impact to the fixed point and the result and the result we take from the point may be not correct. To avoid the impact and improve the accuracy, in this paper, a coordinate difference method to monitor the transformation of high slope with Total station actively is put forward and the principle, error analyses of this method are described and its application in safe monitor of high slope is introduced.     

Horizontal Slice Method for the Stability Analysis of Reinforced Slopes

Relevant national codes usually require the transmitting coefficient method to be employed for the stability analysis of slope reinforcement, in which sliding mass is usually divided into a number of vertical slices.For some support technologies, such as rock bolting and anchor cable, the intersections between the slices and the anchor bar, and the forces mobilized in the reinforcements are different from the assumptions in this method.Thus the transmitting coefficient method confronts some difficulties during practical applications, which would influence the project quality of reinforcements.A new Horizontal Slice Method was proposed based on the overseas relevant literatures to overcome these difficulties in the stability analysis of rock bolting and anchor cable slopes.     

Multiplex analytical method for metal three dimensional flow of heavy rail rolling by universal mill

With the monitoring data of groundwater level of some reservoir slope, the nonlinear combined model was established on the basis of establishing the time series method and speed analysis method. Upon the comparison, it was found that the precision of non linear combined model was higher than that of single model. It was an effective prediction method for groundwater level of reservoir slope and could be employed for stability prediction of reservoir slope.     

露天矿过断层开采方式及生产能力接续分析

在露天开采过程中遇到断层时,由于煤层突然错位,造成剥采比剧变,工程接续困难。因此,过断层期间剥采比合理控制和矿山工程平稳过渡接续是露天开采的技术难题之一。笔者通过建立剥采比与断层落差、产状及煤层厚度数学模型,研究不同煤柱留设宽度对边坡稳定的影响;分析了矿山工程发展速度与同时采煤台阶数的关系,计算确定了过断层期间确保矿山工程平稳过渡接续的动态降深速度和生产能力接续方式。结合胜利东二号露天矿过F61断层进行实例研究。结果表明：过断层开采方式和生产能力接续方法可有效均衡生产剥采比,保证产量稳定,提高矿山经济效益。     

The Stability Analysis of Single end Flyback Switching Power Supplies

Based on the research of a practical project for high hrequency high voltage switching power supplies,the state space average model as well as the transfer function of single end flyback converters,which can be used to analyze the stability of single end flyback switching power supplies,are established.     

利用不同实时定量PCR方法分析相对基因表达差异

利用实时荧光定量PCR方法分析目标基因转录本之间的表达差异,目前常用的分析实验数据的有绝对定量和相对定量方法。为了克服绝对定量方法的繁琐和简化相对定量的分析方法,分别利用2^-ΔΔCT、2^-ΔCT和标准曲线法对水稻OsRDB1基因在不同化学试剂和激素处理下的表达差异进行了分析,发现2^-ΔΔCT必须引入标准的看家基因作为参考,计算方法繁琐,计算结果受扩增效率影响;而利用2^-ΔCT和标准曲线法计算方便,节省定量PCR试剂,但其结果易受到RNA浓度测量准确率的影响,其中标准曲线法引入斜率消除扩增效率的影响,最能测得实际的原始拷贝数差异。