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1.
Prasanta Kumar Behera Kripamoy Sarkar Ashok Kumar Singh A. K. Verma T. N. Singh 《Journal of the Geological Society of India》2016,88(6):725-735
In opencast mining operation, the stability of waste materials stands at high priority from the safety and economic perspective. Poor management of overburden (OB) dump results the instability of slope in an opencast mine. The present paper deals with the stability analysis of dump material of an opencast coal mine at Talcher coal field, Angul district, Odisha, by means of different geotechnical parameters and mineralogical composition affecting the dump slope. The prolonged rainfall in the mining area causes dump failure and loss of valuable life and property. A recent dump failure that occurred in 2013 at Basundhara mines of Mahanadi Coalfields Limited (MCL), Odisha, took 14 lives, and created problems for the mining industry. Most of the dump failure that occurs in the study area are mainly due to increase in pore water pressure as a result of rainfall infiltration. The stability of the waste dump was investigated using the limit equilibrium analysis to suggest an economical, sustainable and safe disposal of the dump in the study area. 相似文献
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The influence of slope aspect on the distribution of landslides was studied in the Milia and Roglio basins in Tuscany, Italy. For each basin, the new Tuscany region landslide inventory that was initiated in 2010 was used. The landslides were split into separate datasets based on their prevailing movement typology. To assess the results that were obtained from the different slope aspect values, maps of the lithology, slope angle, distances to streams, and distances to tectonic lineaments were included in the bivariate statistical analysis as comparison terms. For each basin, all of the geo-environmental factor maps were compared with the different landslide typologies with GIS software. Pearson's Chi2 (χ2) coefficient was used to test the degree of spatial association between each predictor variable and landslide type. In addition, Cramer's V test was used to quantify the strength of the degree of association. Next, a conditional analysis was applied to all of the possible combinations that occurred between the slope aspect and other landslide-predisposing factors. Overall, the slope aspect significantly affected the distribution of superficial landslide types, but apparently not that of other landslide types. 相似文献
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Evaluating cut slope failure by numerical analysis—a case study 总被引：3，自引：3，他引：0
Slope failure is very common phenomenon in hilly regions, especially in young techno active mountainous like Himalayas. It
is hazardous because of the accompanying progressive movement of the slope-forming material. In order to minimize the landslide
effects, slope failure analysis and stabilization requires in depth understanding of the process that governs the behavior
of the slope. The present article mainly deals with the analysis of the stability of road cut slopes of Rudraprayag Area,
Uttarakhand, India. The area experiences local as well as regional slides every year. Extensive field study was carried out
along the road cut slopes. Laboratory experiments were conducted to determine the various Physio-mechanical properties of
rock mass. These properties have been used as input parameters for the numerical simulation of slope using FLAC3D (Fast Lagrangian
Analysis of Continua) including geological discontinuities. The computed deformations and the stress distribution along the
failure surface are compared with the field observations. The study indicates that the overall slope is unstable except at
the location E where slope is critically stable. The effects of instability have been thoroughly considered and remedial measures
have been recommended. 相似文献
5.
Rock slopes with planar joints or weak structural planes are vulnerable in nature, especially suffering from the natural hazards, instabilities of slopes are more prone to occur. Therefore, concerning to the influence of earthquakes, this paper performs a new procedure to evaluate slope stability in a geomaterial governed by Hoek–Brown strength criterion. A rotational failure mechanism determined by 21 dependent angle variables is introduced to respect the Hoek–Brown strength criterion. The earthquake load is characterized by a modified pseudo-dynamic method that does not violate the zero boundary condition and considers the damping properties of geomaterials. A slice approach is adopted to calculate the earthquake-induced inertial force work rate. The stability number of rock slope is considered to measure the safety. The stability number is formulated as a classical optimization problem controlled by 21 dependent angle variables and a time variable which need to be optimized by the genetic algorithm toolbox. Comparisons with the literature are made to prove rationality and accuracy of the proposed procedure. Parametric study is carried out to reveal the influence of dynamic properties. For engineering application, stability charts are provided for a quick assessment of slope safety.
相似文献6.
We discuss issues related to a recognised shortcoming in existing tsunami hazard assessments for Pacific Island Countries and Territories (PICTs), that of tsunamigenic slope failures (TSFs). Currently, TSFs are most likely underrepresented as sources in existing tsunami databases for two key reasons. First, relatively low magnitude earthquakes associated with subduction zones are generally assigned as the tsunamigenic source, as opposed to the TSFs they generate. A reassessment of such ‘anomalous tsunamis’ may yield clues that serve to reassign their tsunamigenic source. Second, there are thousands of oceanic islands and seamounts scattered across the Pacific and flank collapse of volcanic edifices such as these is a largely unquantified tsunamigenic threat. However, while it is now possible to model such TSFs, this is unlikely to happen in the near future because of the lack of detailed bathymetry and landslide mass data. Recent developments in the identification of past tsunamis in the Pacific Islands have developed a unique range of indicators that can be used for identifying such events. These are geological, oral tradition and archaeological components that include, but are not limited to, a modified Darwinian model of atoll formation, coastal megaclasts, oral traditions of vanished islands and giant waves, and the abandonment of prehistoric coastal sites. As such, the most logical way forward is to use the multiple indicators available to us to identify evidence of past tsunamis. 相似文献
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In this paper, the authors present a probabilistic back-analysis of a recent slope failure at a site on Freeway No. 3 in northern Taiwan. Post-event investigations of this failure found uncertain strength parameters and deteriorating anchor systems as the most likely causes for failure. Field measurement after the event indicated an average slip surface of inclination 15°. To account for the uncertainties in input parameters, the probabilistic back analysis approach was adopted. First, the Markov Chain Monte Carlo (MCMC) simulation was used to back-calculate the geotechnical strength parameters and the anchor force. These inverse analysis results, which agreed closely with the findings of the post-event investigations, were then used to validate the maximum likelihood (ML) method, a computationally more efficient back-analysis approach. The improved knowledge of the geotechnical strength parameters and the anchor force gained through the probabilistic inverse analysis better elucidated the slope failure mechanism, which provides a basis for a more rational selection of remedial measures. 相似文献
8.
Stability of slope will always a problem due to its geodynamic nature of Himalayan region. The area investigated belongs to
the Lower Siwalik formation, which is prone to failure due to presence of various weak planes or structures present in the
rock mass. Frequent landslides causing loss of life, property, disturbance of morphological, surface and subsurface water
flow pattern. A huge landslide in the Amiyan area occurred in 1999 and blocked the Gaula River which caused loss of agricultural
land and other properties as well as waterlogged upstream side. The debris of Amiyan slope contains soil and sandstones of
various types. This article deals with instability analysis of slopes of the Amiyan area, near Kathgodam, Nainital, Uttarakhand.
This area experiences a number of local as well as regional slides. Extensive field surveys have been carried out to understand
the geological detail. Laboratory experiments have been conducted to determine the various physicomechanical properties of
rock mass. These properties have been used as input parameters for the numerical simulation. A number of researchers have
used two-dimensional numerical models to simulate the slide area. Three-dimensional slope stability studies provide a better
understanding of the mechanism of failure as well as zone of influence. The computed deformations and stress distribution,
along the failure surface, have been compared with the field measurements and found to be in good agreement with field observations.
In this case, finite difference method has been applied on the stability analysis of Amiyan slope. The study indicates that
the slope is vulnerable and needs proper protection. 相似文献
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Warning systems are increasingly applied to reduce damage caused by different magnitudes of rockslides and rockfalls. In an integrated risk-management approach, the optimal risk mitigation strategy is identified by comparing the achieved effectiveness and cost; estimating the reliability of the warning system is the basis for such considerations. Here, we calculate the reliability and effectiveness of the warning system installed in Preonzo prior to a major rockfall in May 2012. “Reliability” is defined as the ability of the warning system to forecast the hazard event and to prevent damage. To be cost-effective, the warning system should forecast an event with a limited number of false alarms to avoid unnecessary costs for intervention measures. The analysis shows that to be reliable, warning systems should be designed as fail-safe constructions. They should incorporate components with low failure probabilities, high redundancy, have low warning thresholds, and additional control systems. In addition, the experts operating the warning system should have limited risk tolerance. In an additional hypothetical probabilistic analysis, we investigate the effect of the risk attitude of the decision makers and of the number of sensors on the probability of detecting the event and initiating a timely evacuation, as well as on the related intervention cost. The analysis demonstrates that quantitative assessments can support the identification of optimal warning system designs and decision criteria. 相似文献
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Ali M. A. Abd-Allah E. K. El-Sawy El-Sayed Sedek Abu Seif Abdelhamid El-Fakharani Mohammed Amin M. Sharaf 《Arabian Journal of Geosciences》2014,7(10):4029-4042
The present contribution is a complete study extending before, during, and after the excavation of the mountain side that lying north of road 7. It includes slope stability analysis, rock cut design, and rockfall modeling for natural slope and rock cut face. Neoproterozoic granodiorite and biotite granite forming the slope body have medium to very high strengths. Mineral compositions and textures of these intact rocks control the strength values. These rocks are intensively dissected by fractures that are filled with montmorillonite and chlorite. The high plasticity and slippery nature of these filling materials represent the main problem that may face a rock cut designer because they damage the mechanical properties of these fractures. The problem begins with the selection of the rock mass classification that deals with the fracture fillings and extends during the stability analysis and the suggestion of mitigation and supporting measures. The rock masses building the natural slope are suffered by plane, wedge, and toppling failures. Therefore, two rock cut designs are suggested to avoid the hazards related to these failures and considering the construction cost as well. Rockfall modeling for the natural slope and rock cut designs was done to assess the hazards related to these falling of the blocks. The kinetic energy of falling blocks is represented on the roadway by the coverage distance and block rebound amplitude. Slope height has a positive effect on the values of these distance and amplitude, whereas the steepness of berm height has a negative effect on them. Coverage distance is a function to the location of rockfall barrier and to the width of road ditch, while the amplitude controls the barrier height. 相似文献
12.
Rainwater infiltration during typhoons tends to trigger slope instability. This paper presents the results of a study on slope
response to rainwater infiltration during heavy rainfall in a mountain area of Taiwan. The Green-Ampt infiltration model is
adopted here to study the behavior of rainwater infiltration on slopes. The failure mechanism of infinite slope is chosen
to represent the rainfall-induced shallow slope failure. By combining rain infiltration model and infinite slope analysis,
the proposed model can estimate the occurrence time of a slope failure. In general, if a slope failure is to happen on a slope
covered with low permeability soil, failure tends to happen after the occurrence of the maximum rainfall intensity. In contrast,
slope failure tends to occur prior to the occurrence of maximum rainfall intensity if a slope is covered with high-permeability
soil. To predict the potential and timing of a landslide, a method is proposed here based on the normalized rainfall intensity
(NRI) and normalized accumulated rainfall (NAR). If the actual NAR is higher than the NAR calculated by the proposed method,
slope failure is very likely to happen. Otherwise, the slope is unlikely to fail. The applicability of the proposed model
to occurrence time and the NAR–NRI relationship is evaluated using landslide cases obtained from the literature. The results
of the proposed method are close to that of the selected cases. It verifies the applicability of the proposed method to slopes
in different areas of the world.
An erratum to this article can be found at 相似文献
13.
《Gondwana Research》2014,26(4):1357-1368
Oceanic Anoxic Event 2 (OAE 2) during the Cenomanian–Turonian (C/T) transition caused stepwise marine extinctions. Using organic compounds, stable carbon and oxygen isotopes, and foraminifera from three depth-transect sections in northern Spain, this study revealed repeated anoxic/euxinic events coinciding with warming and stepwise extinctions of planktonic and/or benthic foraminifera within intermediate to surface waters in the proto-North Atlantic during the C/T transition. Those short-duration euxinic events occurred four times: at 93.95 Ma, marked by the extinction of Rotalipora greenhornensis; at 93.90 Ma, marked by the extinction of Rotalipora cushmani; at the mid-time maximum of the plateau of the δ13C of carbonates (93.70 Ma); and at the time of the C/T boundary (93.55 Ma). Furthermore, the main benthic foraminiferal extinctions occurred during the first and second euxinic events in the upper slope, during the second and third euxinic events in the outer to middle shelf, and during the third and fourth events in the middle shelf. The main euxinic events in each section also showed a progression to the shallow shelf. The main anoxia–extinction events occurred in the upper slope and outer shelf then moved to the middle shelf. The shallowest section had relatively weak anoxia and a proportionally low extinction rate. These new findings indicate that foraminiferal extinctions started from the intermediate water and the continental slope and then moved to the continental shelf. This was the result of the repeated progression of euxinic–anoxic water from the upper slope to the middle shelf on the eastern continental margin of the proto-North Atlantic four times during a 400 kyr period, to the end of the Cenomanian. 相似文献
14.
Numerical modelling of rock slides is a versatile approach to understand the failure mechanism and the dynamics of rock slopes. Finite element slope stability analysis of three rock slopes in Garhwal Himalaya, India has been carried out using a two dimensional plane strain approach. Two different modelling techniques have been attempted for this study. Firstly, the slope is represented as a continuum in which the effect of discontinuities is considered by reducing the properties and strength of intact rock to those of rock mass. The equivalent Mohr-Coulomb shear strength parameters of generalised Hoek-Brown (GHB) criterion and modified Mohr-Coulomb (MMC) criterion has been used for this continuum approach. Secondly, a combined continuum-interface numerical method has been attempted in which the discontinuities are represented as interface elements in between the rock walls. Two different joint shear strength models such as Barton-Bandis and Patton’s model are used for the interface elements. Shear strength reduction (SSR) analysis has been carried out using a finite element formulation provided in the PHASE2. For blocky or very blocky rock mass structure combined continuum-interface model is found to be the most suitable one, as this model is capable of simulating the actual field scenario. 相似文献
15.
Yanjun Shang Chang-Uk Hyun Hyeong-Dong Park Zhifa Yang Guangxiang Yuan 《Environmental Earth Sciences》2017,76(1):47
The evolution of large-scale landslides should be studied because, over long periods of time, primary remediation measures may suffer reduced efficiency or have to be adjusted many times. The 102 Landslide in southeast Tibet, which originally formed in 1991 with a volume of 5.1 million m3 and still exhibits post-failure activity, provides a distinctive case study. The landslide evolved from earthquake destruction and unloading, rainfall-triggered sliding, and debris flow to sands sliding slopes. The NE ringed scarp receded by 38.96 m during a five-year period (2003–2008). The total recession was 160 m with a total area of 2500 m2 during a 17-year period (1991–2008). Although several types of remediation measures were applied and were temporarily effective, the normal function of the Sichuan–Tibet Highway was affected by landslide reactivation from time to time. Actual effects of the engineering measures such as retaining walls, prestressed anchor cables, and drainage ditches confirm that hasty governance of this type of large-scale landslide is generally unfeasible over long time periods. Finally, an approach involving a tunnel running backward from the front face has been adopted as a permanent solution to large-scale moraine slope failures: This engineering practice has been in progress since April 2012. This paper describes the evolution of the 102 Landslide, the engineering interventions to mitigate the effects of the landslide on the Sichuan–Tibet Highway, and the choice of tunneling as a final mitigation measure. The present study concludes that approaches that allow escape from developing geo-hazards should always be the initial choice. 相似文献
16.
How to evaluate reasonably the stability of a soil slope reinforced with piles (SSRP) still is an urgent problem. At present, the three-dimensional (3D) finite element strength reduction method has been used for the soil slope stability analysis. However, to accurately determine the global instability of soil slopes is the key to implementing the strength reduction finite element method. In this paper, the 3D finite element strength reduction algorithm (FESRA), based on Hill’s model theory, is proposed to assess the stability of SSRP and study on the relationship between the safety coefficients of SSRP and the displacements of slope mass. The results show that: (1) the relationship between the safety coefficients of SSRP and the displacements of slope mass agrees with the Hill’s model; (2) the proposed method (3D FESRA based on Hill’s model theory) in this study may take into account simultaneously the pile response and slope stability, and makes the results of SSRP stability analysis reasonable and reliable, which could be used as a reference for the evaluation of stability of the same type of slope; and (3) further study should be done to confirm whether the proposed method in this study is suitable for other types of slopes. 相似文献
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考虑结构面抗剪强度震动退化效应对分析与评价岩质边坡动力稳定性具有重要意义。基于岩石动力试验获取了多因素影响的结构面强度震动退化系数方程,结合极限平衡理论和动态矢量法原理,以UDEC程序作为计算引擎,采用其内置Fish语言编程实时刷新结构面强度特性参数和捕获任意地震历时时刻边坡地震惯性力,并以最小平均安全系数法求解边坡最终动力稳定性评价指标值,从而提出了一种考虑结构面强度震动退化的边坡动力稳定性系数动态算法。研究表明:结构面强度震动退化系数是取决于岩块间循环剪切次数、循环剪切幅度及相对运动速度响应值的动态变量;将该算法应用于含贯通型平直状结构面边坡动力稳定性算例中,其分析结果表明,动力作用时程内考虑结构面强度震动退化的边坡动力稳定性系数较未考虑该效应时的系数衰减更为明显,即前者计算结果更符合一般性自然规律,亦即验证了该算法的可行性;结构面最小强度震动退化系数随动力激励时程变化近似呈负指数函数形式逐渐衰减,且当结构面初始黏聚力(内摩擦角)越大、而坡角(层面倾角)或动荷载幅值(频率)越小时,地震历时过程中边坡最小动力稳定性系数越大,此时边坡最终动力稳定性相对越强。 相似文献
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The Gradenbach mass movement (GMM) is an example of DGSD (deep-seated gravitational slope deformation) in crystalline rocks of the Eastern Alps (12.85°E, 47.00°N). The main body of the GMM covers an area of 1.7 km2 and its volume is about 120?×?106 m3. A reconstruction of the deformation history yields a mean displacement of?～?22 m from 1962 to 2011. In 1965/66, 1975, 2001, and 2009 high sliding velocities, exceeding several meters per year, interrupt the quasi-stationary periods of slow movement (≤0.3 m/year). Since 1999 the displacement of the main body of the GMM has been observed by GPS. Time series of extensometer readings, precipitation, snow cover water equivalent, water discharge, and hydrostatic water level observed in boreholes were re-processed and are presented in this paper. Continuous recording of seismic activity by a seismic monitoring network at the GMM began in the summer of 2006. Deformation has been monitored since 2007 by an embedded strain rosette based on fiber optics technology and a local conventional geodetic deformation network. The velocity of the GMM could be modeled to a large extent by a quantitative relation to hydro-meteorological data. During the phase of high sliding velocity in spring 2009, the seismic activity in the area increased significantly. Several types of seismic events were identified with some of them preceding the acceleration of the main body by about 6 weeks. The potential inherent in the Gradenbach Observatory data to supply early warning and hazard estimation is discussed. 相似文献