Evaluation of slope stability through rock mass classification and kinematic analysis of some major slopes along NH-1A from Ramban to Banihal, North Western Himalayas

The network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes,which is vital for India’s socio-economic growth.Due to natural and artificial factors,frequency of slope instabilities along the networks has been increasing over last few decades.Assessment of stability of natural and artificial slopes due to construction of these connecting road networks is significant in safely executing these roads throughout the year.Several rock mass classification methods are generally used to assess the strength and deformability of rock mass.This study assesses slope stability along the NH-1A of Ramban district of North Western Himalayas.Various structurally and non-structurally controlled rock mass classification systems have been applied to assess the stability conditions of 14 slopes.For evaluating the stability of these slopes,kinematic analysis was performed along with geological strength index(GSI),rock mass rating(RMR),continuous slope mass rating(CoSMR),slope mass rating(SMR),and Q-slope in the present study.The SMR gives three slopes as completely unstable while CoSMR suggests four slopes as completely unstable.The stability of all slopes was also analyzed using a design chart under dynamic and static conditions by slope stability rating(SSR)for the factor of safety(FoS)of 1.2 and 1 respectively.Q-slope with probability of failure(PoF)1%gives two slopes as stable slopes.Stable slope angle has been determined based on the Q-slope safe angle equation and SSR design chart based on the FoS.The value ranges given by different empirical classifications were RMR(37-74),GSI(27.3-58.5),SMR(11-59),and CoSMR(3.39-74.56).Good relationship was found among RMR&SSR and RMR&GSI with correlation coefficient(R 2)value of 0.815 and 0.6866,respectively.Lastly,a comparative stability of all these slopes based on the above classification has been performed to identify the most critical slope along this road.

Classification and rating of disintegrated dolomite strata for slope stability analysis

Although disintegrated dolomite,widely distributed across the globe,has conventionally been a focus of research in underground engineering,the issue of slope stability issues in disintegrated dolomite strata is gaining increasing prominence.This is primarily due to their unique properties,including low strength and loose structure.Current methods for evaluating slope stability,such as basic quality(BQ)and slope stability probability classification(SSPC),do not adequately account for the poor integrity and structural fragmentation characteristic of disintegrated dolomite.To address this challenge,an analysis of the applicability of the limit equilibrium method(LEM),BQ,and SSPC methods was conducted on eight disintegrated dolomite slopes located in Baoshan,Southwest China.However,conflicting results were obtained.Therefore,this paper introduces a novel method,SMRDDS,to provide rapid and accurate assessment of disintegrated dolomite slope stability.This method incorporates parameters such as disintegrated grade,joint state,groundwater conditions,and excavation methods.The findings reveal that six slopes exhibit stability,while two are considered partially unstable.Notably,the proposed method demonstrates a closer match with the actual conditions and is more time-efficient compared with the BQ and SSPC methods.However,due to the limited research on disintegrated dolomite slopes,the results of the SMRDDS method tend to be conservative as a safety precaution.In conclusion,the SMRDDS method can quickly evaluate the current situation of disintegrated dolomite slopes in the field.This contributes significantly to disaster risk reduction for disintegrated dolomite slopes.

Analysis of high-power disk laser welding stability based on classification of plume and spatter characteristics

Classification of plume and spatter images was studied to evaluate the welding stability. A high-speed camera was used to capture the instantaneous images of plume and spatters during high power disk laser welding. Characteristic parameters such as the area and number of spatters, the average grayscale of a spatter image, the entropy of a spatter grayscale image, the coordinate ratio of the plume centroid and the welding point, the polar coordinates of the plume centroid were defined and extracted. Karhunen-Loeve transform method was used to change the seven characteristics into three primary characteristics to reduce the dimensions. Also, K-nearest neighbor method was used to classify the plume and spatter images into two categories such as good and poor welding quality. The results show that plume and spatter have a close relationship with the welding stability, and two categories could be recognized effectively using K-nearest neighbor method based on Karhunen-Loeve transform.

GREY CLASSIFICATION FOR EVALUATING THE STABILITY OF DANGEROUS ROCK-BLOCK MASSES

This paper introduces a grey classifica- tion method forevaluating the stability of dangerous rock- block masses according tothe Grey System Theory. This method is applied to the stability ofthe V~# dangerous rock- block masses of Qingjiang water conservancyproject, and better results are abtained. The method which isadvanced in the article is very single and practical, and it can meetall kinds of project's demands.

Application of rock mass classification systems to rock slope stability assessment:A case study

The stability of rock slopes is considered crucial to public safety in highways passing through rock cuts, as well as to personnel and equipment safety in open pit mines. Slope instability and failures occur due to many factors such as adverse slope geometries, geological discontinuities, weak or weathered slope materials as well as severe weather conditions. External loads like heavy precipitation and seismicity could play a significant role in slope failure. In this paper, several rock mass classification systems developed for rock slope stability assessment are evaluated against known rock slope conditions in a region of Saudi Arabia, where slopes located in rugged terrains with complex geometry serve as highway road cuts. Selected empirical methods have been applied to 22 rock cuts that are selected based on their failure mechanisms and slope materials. The stability conditions are identified, and the results of each rock slope classification system are compared. The paper also highlights the limitations of the empirical classification methods used in the study and proposes future research directions.

Stability classification model of mine-lane surrounding rock based on distance discriminant analysis method

Based on the principle of Mahalanobis distance discriminant analysis (DDA) theory, a stability classification model for mine-lane surrounding rock was established, including six indexes of discriminant factors that reflect the engineering quality of surrounding rock: lane depth below surface, span of lane, ratio of directly top layer thickness to coal thickness, uniaxial comprehensive strength of surrounding rock, development degree coefficient of surrounding rock joint and range of broken surrounding rock zone. A DDA model was obtained through training 15 practical measuring samples. The re-substitution method was introduced to verify the stability of DDA model and the ratio of mis-discrimination is zero. The DDA model was used to discriminate 3 new samples and the results are identical with actual rock kind. Compared with the artificial neural network method and support vector mechanic method, the results show that this model has high prediction accuracy and can be used in practical engineering.

COMPARISON OF SOME LIMITS FOR STABILITY CLASSIFICATION

Stability parameters (Monin-Obukhov length L, gradient Richardson number Ri and bulk Rischardson number Ri), which are applicable in urban environment, were discussed for ways of calculating classification standards. Gradient observations from a 325-m meteorological tower in Beijing are used to categorize Rib based on three different standards of stability proposed by D. Golder, Irwin and Houghton. The results show that it is relatively reasonable for the region of Beijing to apply the classification standard by Irwin.

Estimation of Atmospheric Stability Classification for the North Coast of Egypt

Studies of atmospheric dispersion are essential to both the site selection of a nuclear power plant and the evaluation of the environmental impacts of nuclear operations. Atmospheric stability plays the most important role in the dispersion of air pollutants. The focus of attention in the present study is the estimation of the degree of stability of the atmosphere for the north coast of Egypt to evaluate the ability of the atmosphere to disperse pollutants. A FORTRAN program （Appendix 1） is presented to determine atmospheric stability using the Pasquill-Tunner Method PTM, which defines the turbulent state of the atmosphere and also reflects upon the dispersion capabilities of the atmosphere at the site. This method used several meteorological factors such as wind speed, insulation, cloud cover height and type. Meteorological data from Matrouh stations in Egypt is applied for a simulated model. The total patterns of stability classification, both monthly and seasonal patterns, are determined, also the stability-wind rose and stability-wind summary are provided. Finally prediction of Iodine surface air concentration is reported as well as the annual effective dose for I- 131 as a case study.

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 Hoek-Brown failure criterion was found suitable to estimate geo-mechanical parameters. After that, the value of cohesion （c） and friction angle （tp） 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.

Kinematic Analysis and Rock Mass Classifications for Rock Slope Failure at USAID Highways

Rock slope kinematic analysis and rock mass classifications has been conducted at the 17^(th) km to 26^(th) km of USAID(United States Agency for International Development)highway in Indonesia.This research aimed to examine the type of rock slope failures and the quality of rock mass as well.The scan-line method was performed in six slopes by using a geological compass to determine rock mass structure on the rock slope,and the condition of joints such as persistence,aperture,roughness,infilling material,weathering and groundwater conditions.Slope kinematic analysis was performed employing a stereographic projection.The rock slope quality and stability were investigated based on RMR(rock mass rating)and SMR(slope mass rating)parameters.The rock slope kinematic analysis revealed that planar failure was likely to occur in Slope 1,3,and 4,the wedge failure in Slope 1 and 6,and toppling failure in Slope 2,5,and 6.The RMR rating is ranging from 57 to 64 and can be categorized as Fair to Good rock.The SMR rating revealed that the failure probability of Slope 3 was 90%,while it was from 40%to 60%for others.Despite the uniform RMR for all slopes,the SMR was significantly different.The detailed quantitative consideration of orientation of joint sets and geometry of the slope contributed to such differences in outcomes.

Comparative Analysis of the Hard Hillsides Stability by Empirical Methods and Limit Equilibrium: Case of Ultra Basic and Andesites of Mako and Marbles of Bandafassi (Senegal)

The purpose of this paper is to characterize rock mass stability using basic rock mass method and to compare them. Rock mass quality and strength are determined using rock mass classification and numerical methods. The Factors of safety are calculated with the results of stereographic projection. Results show that quality of ultrabasite and marble are better than quality of andesite. The Slope Mass Ratings (SMR) show that rocks with the best quality are stable and andesite partially stable. The calculation of the factors of Safety by limit equilibrium assigns a stable state for ultrabasite and marble and instable for andesite. Calculation of Safety factor using stereographic parameters in one hand and finite element code in another shows more possibility of planar sliding along discontinuities than rock matrix failure. At last, quality of endogeneous rock mass is correlated with its stability state. The better rock mass is, the more stable the rock it is.

Measurement-based Cell-DT Method for Power System Transient Stability Classification

In this paper,a combined Characteristic Ellipsoid(CELL)and Decision Tree(DT)method for fast classifying the transient stability of power systems after a large disturbance is proposed.The proposed two-stage method involves projection of the PMU measurement data after the disturbance on a multidimensional space to form the CELL and then classification of the transient stability using DT which takes the characteristic attributes of CELL under different fault scenarios as input features.The dynamic behaviors after a disturbance for both stable and unstable situations are identified from the variation of the CELL’s shape.The database,composed of the geometrical properties of the CELL such as volume,eccentricity,center and change rate of volume,is used to train a DT for transient stability classification.Case study on a IEEE 39-bus system demonstrates the feasibility of the proposed method.Investigations show that the proposed method requires less information from the system to fast classify the transient stability with high precision.

“双高”电力系统:一种新的稳定判据和稳定性分类探讨

随着能源变革和电力电子技术发展,高比例新能源和高比例电力电子设备(简称“双高”)在电力系统中比例增高,带来新的稳定问题。该文对“双高”电力系统的失稳影响因素和稳定判据进行深入剖析,探索“双高”电力系统的失稳机理,提出系统阻抗角稳定性分析方法。基于所提出的稳定性分析方法,从系统有功功率、无功功率平衡基本运行规则出发,构建“双高”电力系统的阻抗角稳定判据,通过搭建仿真模型验证所提稳定判据的有效性和正确性。同时,对IEEE 提出的稳定性分类进行探讨,在遵循传统稳定性分类原则基础上,基于所构建的稳定判据,尝试提出一种新的稳定性分类方法,希望有助于厘清“双高”电力系统稳定性问题,为后续系统规划、稳定性控制提供指导。

隧道穿越岩堆体围岩剪切特性及分级

为解决隧道穿越岩堆体围岩分级不准确的问题,通过相似材料直剪试验分析岩堆体的直剪特性,将含水率和填充土含量两个因素带入熵权可拓物元法,并结合地质指标进行分级研究。结果表明岩堆体的抗剪强度随着含水率、填充土含量的增大,先增大后减小,最终趋于平稳,过高或过低的含水率和填充土都会“弱化”岩堆体的抗剪强度。根据岩堆体的特点,选取岩石单轴饱和抗压强度、节理裂隙密度、岩体完整性系数、含水率和填充土含量作为分级指标,结合熵权可拓物元法,将所选指标和熵权可拓物元法结合并在工程实例进行验证,分级结果比原方法准确性更好,证明研究提出的围岩分级方法是合理可行的。研究结果能够为岩堆体隧道的围岩分级提供指导,为施工设计和支护方式提供依据。

基于安全系数的挤压性围岩隧道围岩稳定性研究

从挤压性围岩概念出发,采用抗剪强度表达的围岩安全系数法评价围岩稳定性,推导了用应力偏张量表示的围岩安全系数表达式,通过FLAC3D二次开发,实现围岩安全系数的数值表达.探讨了变形等级和断面形状对围岩稳定性的影响规律,并研究了注浆加固对围岩稳定性的影响规律.研究结果显示,与塑性区评价方法相比,围岩安全系数法可以实现任何位置的围岩破坏程度定量评价;围岩破坏边界呈蝴蝶形分布;隧道断面面积越大,围岩破坏范围越大;隧道越接近圆形,围岩相对破坏范围越小,圆形为最优断面形状;超前注浆加固对围岩稳定性的改善效果优于径向注浆加固.研究结果为挤压性围岩隧道结构设计和施工变形控制提供参考。

基于拓展的Mathews稳定图法和数值模拟的采空区稳定性分析

某铅锌矿经多年开采遗留下一些未处理采空区,为进行后续开采,现需对采空区进行稳定性研究。通过拓展的Mathews稳定图法、FLAC3D数值模拟软件进行研究,并基于Mathews稳定图法分析暴露时间对采空区稳定性的影响。以矿山三个未处理采空区作为研究对象,利用RMR和Q′值进行岩体质量分级,根据获得的岩体力学参数,使用增加了稳定性等概率线的Mathews稳定图,计算出采空区顶板及上盘的稳定性及稳定概率;计算考虑暴露时间的采空区稳定性概率,进行比较;利用FLAC3D数值模拟软件对采空区进行稳定性数值模拟分析,并与Mathews合成图得出的结果进行对比。结果表明:综合Mathews稳定图法和FLAC3D数值模拟,6204采空区顶板评价结果为不稳定,其他采空面均为稳定;随着暴露时间的增加,采空区稳定性随之降低,且对岩性较差的采空区有较大影响;拓展的Mathews稳定图法与数值模拟可以相互验证,综合分析采空区的稳定性。

基于加权隶属度矩阵的岩体质量优化分级及支护研究

巷道围岩质量分级是巷道围岩稳定性分析、合理支护设计与施工的基础。提高分级结果的准确性,是提升支护效果和巷道围岩稳定性的关键途径。以RMR法为基础,以某一测点的分级因素指标值为例,构建RMR法各分级指标的隶属度矩阵,再结合熵值法确定分级指标的权重,得到加权隶属度矩阵,构造优化后的评分公式,进行指标优化评分和围岩质量分级,然后根据围岩质量分级结果及松动圈监测结果设计支护参数,利用FLAC3D进行模拟计算以巷道围岩塑性区体积和顶底板收敛量为评价指标,研究优化前后的支护效果。研究结果表明:经过优化后的指标评分和围岩等级更加准确,巷道支护参数设计更加合理,数值模拟结果显示其能有效地提升围岩的稳定性,并将优化后的支护设计参数应用于工程,取得了良好的效果。研究成果可有效解决巷道围岩分级因素指标值位于分级边界或分级跨度大的问题,为矿山岩体质量分级与支护设计提供参考。

基于边界强化混合采样的两阶段电力系统暂态稳定评估

受制于样本固有的不平衡性,基于数据挖掘的暂态稳定预测方法不易用于工程实践,为此,提出一种基于边界强化混合采样的两阶段暂态稳定评估模型。在第1阶段,利用预训练的级联卷积神经网络模型确定边界和非边界样本集,利用条件生成对抗网络合成边界集失稳样本,并对非边界集稳定样本进行欠采样,以实现边界强化;在第2阶段,利用混合采样后的重构样本集再训练卷积神经网络模型,以更好地挖掘失稳样本的隐含特征,并采用改进后的焦点损失函数加强模型对边界集样本的学习能力。新英格兰39节点系统与南方某省级电网的仿真结果表明,所建模型有效降低了对失稳样本的漏判率,提高了整体预测精度,在样本极不平衡的情况下仍有良好的评估性能。

基于关键块体的井巷围岩稳定性分析及支护研究

为了进一步研究关键块体对巷道围岩稳定性的影响及通过关键块体分析进行支护措施的设计。以蒙库铁矿地下开采某一巷道为研究对象,通过工程地质调查与现场测试工作,对围岩节理裂隙统计与分段,并进行岩块强度试验和岩体的波速测试,获得了岩体完整性参数,依据此进行了详细的岩体工程分级,给出不同岩体的分级力学参数,再通过Unwedge进行关键块体分析,对不稳定岩块进行划定,确定了锚喷支护的参数及重点支护位置,然后采用有限元软件模拟开挖过程并分析了开挖过程中围岩及支护的应力应变变化情况,最后进行现场采动应力的监测与分析。研究结果表明:经过关键块体分析,更准确地辨别出可能导致巷道失稳的不稳定岩块,针对关键块体分析结果提出稳定性支护措施,并应用于现场,进行采动应力监测与分析,取得了良好的效果。研究结果在一定程度上为围岩稳定性分析及支护设计提供了可靠依据。

基于Mathews的某铁矿残留间柱回采结构参数研究

为提高矿山生产能力,延长矿山服务年限,对某铁矿矿量大、价值高的残留间柱,进行分段充填采矿法进行回采。通过现场地质调查室内岩石力学试验,对矿山岩体质量进行了综合评价。结果表明,矿山岩体和矿体的岩体质量良好,满足了安全生产的基本要求。基于Mathews稳定性图解法,本文进一步对矿山分段充填采矿法试验采场进行了优化研究。通过详细分析和计算,确定了该矿山的最佳采场结构参数,包括采场宽度为14 m、长度为25 m。这些优化参数能够有效提高采矿过程的稳定性和安全性,为矿山后期生产提供了科学可靠的理论数据支撑。研究结果不仅为类似矿山的采场设计提供了有力参考,还为进一步提升矿山生产效率和安全水平奠定了基础。