Freshly updated and extended version of Slope Analysis (Chowdhury, Elsevier, 1978). This reference book gives a complete overview of the developments in slope engineering in the last 30 years. Its ...multi-disciplinary, critical approach and the chapters devoted to seismic effects and probabilistic approaches and reliability analyses, reflect the distinctive style of the original. Subjects discussed are: the understanding of slope performance, mechanisms of instability, requirements for modeling and analysis, and new techniques for observation and modeling. Special attention is paid to the relation with the increasing frequency and consequences of natural and man-made hazards. Strategies and methods for assessing landslide susceptibility, hazard and risk are also explored. Moreover, the relevance of geotechnical analysis of slopes in the context of climate change scenarios is discussed. All theory is supported by numerous examples.
"...A wonderful book on Slope Stability...recommended as a refernence book to those who are associated with the geotechnical engineering profession (undergraduates, post graduates and consulting engineers)..." Prof. Devendra Narain Singh, Indian Inst. of Technology, Mumbai, India"I have yet to see a book that excels the range and depth of Geotechnical Slope Analysis... I have failed to find a topic which is not covered and that makes the book almost a single window outlet for the whole range of readership from students to experts and from theoreticians to practicing engineers..." Prof. R.K. Bhandari, New Delhi, India
Lead-free inorganic cubic halide perovskites exhibit outstanding physical properties in solar technology. Ba3NCl3 emerges as a promising absorber material in solar cells. Utilizing first-principles ...density-functional theory (FP-DFT), we thoroughly analyzed Ba3NCl3 properties. It exhibits mechanical, dynamically stability and natural ductility. Electron charge distributions indicate significant ionic bonding between Ba and Cl, and covalent bonding between N and Cl. At the Γ-point, the direct bandgap of PBE(HSE) is 0.57 eV (1.20 eV). Dielectric functions, absorption coefficients, and conductivity confirm robust absorption characteristics across the visible-ultraviolet spectrum. SCAPS-1D simulation identified optimal PV parameters for Ba3NCl3-based cells with a WS2 buffer layer, considering various layer thicknesses and doping densities. In an Al/FTO/WS2/Ba3NCl3/Au structure, under ideal conditions, impressive metrics include an open circuit voltage (VOC) of 1.036 V, photocurrent density (JSC) of 38.21 mA/cm2, fill factor (FF) of 80.75 %, and maximum power conversion efficiency (PCE) of ∼ 32 %. Ba3NCl3 shows promise as a potential absorber in hybrid perovskite photovoltaic devices, especially with WS2 electron transport layers.
In the past, residual factor R in strain-softening soil slopes has been included, either directly or indirectly, as a deterministic variable in both deterministic and probabilistic studies. This ...paper discusses the uncertainties associated with R and outlines a systematic approach for the reliability analysis of a natural slope in which shear strength parameters and pore pressure ratio are random variables, each assumed with a lognormal probability distribution. For the residual factor R, seven probability distribution options under the generalized beta-distribution system are considered. Slope reliability is computed based on the first order reliability method (FORM) and validated against Monte-Carlo simulation (MCS). Results obtained from two illustrative examples indicate that the probability of failure, with R as one of six random variables, can be orders of magnitude higher than that based on five random variables with R considered as a deterministic parameter. The magnitude of influence of R as a random variable is, however, highly dependent on its probability distribution, the left-skewed triangular distribution having the most significant influence in both the examples. Results of sensitivity analyses reveal that, for almost all of its assumed probability distributions, R is the most dominant among the six random variables. Effects of variation of some of the statistical and correlation properties of the other random variables, viz. the shear strength parameters and the pore pressure ratio, on the results of reliability analyses are also studied.
The paper concerns to the reliability analysis of slopes in strain-softening cohesive soils, using the first order reliability method (FORM). The performance function is based on the Bishop ...simplified method adapted to take strain-softening into account in terms of the residual factor
R
F
over a potential slip surface, estimated based on a progressive failure model available in the literature. The reliability analysis is carried out on the surface of minimum factor of safety determined using the sequential quadratic programming (SQP). The random shear strength parameters are assumed to follow normal distribution while the residual factor has been considered both as a deterministic parameter and a beta-distributed random variable. The results obtained for an illustrative example shows substantial reduction (21 %) in the value of reliability index when
R
F
is considered as a random variable with an assumed COV of 0.3. Results of FORM-based sensitivity analyses also reveal that
R
F
has the most dominating influence on reliability and thus justifies its inclusion as one of the random variables. A parametric study, varying the assumed correlation coefficient between the random shear strength parameters from 0 to 1, shows that there is a maximum reduction of 16 % in reliability index.
This paper is a contribution to an important aspect of the systematic and quantitative assessment of landslide hazard and risk. The focus is on site-specific and detailed assessment for ...rainfall-triggered landslides and, in particular, on the estimation and interpretation of the temporal probability of landsliding. Historical rainfall data over a 109-year period were analysed with particular reference to a site along the Unanderra and Moss Vale Railway Line in the State of New South Wales, Australia. It is shown that the recurrence interval of landsliding and hence annual probability of occurrence is subject to significant uncertainty and that it cannot be regarded as a constant. Accordingly landslide hazard varies spatially as well as being a function of time. For the example case study considered in this paper the annual probability of landslide occurrence was estimated to be in the range 0.026-0.172. However, the mean annual probability of landslide reactivation was estimated to be in the range 0.037-0.078. Utilisation of methods for probability assessment proposed in this paper will contribute to more realistic assessment of hazard and risk and, therefore, to more efficient risk management.PUBLICATION ABSTRACT
The reliability of geotechnical structures of short-term stability is largely affected by uncertainties contained in measured undrained strength of soils. The main sources of the uncertainties are ...(1) the inherent random variation of soil property in the in-situ ground, (2) stress release in boring, (3) mechanical disturbance during sampling and trimming of soil specimen, and (4) testing errors. These uncertainties are modeled in probabilistic manner and a new probabilistic model of measured undrained strength is proposed for normally consolidated and or lightly overconsolidated clay. The proposed model is attested by some actual data, and it is concluded that the proposed model can well predict the statistical parameters of in-situ undrained strength on the basis of those of the measured undrained strength.
Seismic slope stability is one of the most important areas of geotechnical earthquake engineering. Over the last century there has been an increasing awareness of the adverse impact of earthquakes on ...slopes, embankments and dams. Catastrophic seismic effects include landslides in natural slopes and the failures of dams and embankments caused either by loss of stability or because of unacceptable magnitude of deformations. Over the last 60 years or so, the response of slopes and earth structures to seismic shaking has attracted tremendous research interest amongst geotechnical engineers. Seismically-triggered failures may be associated with reduction in factor of safety, large deformations and liquefaction phenomena. Research has included the testing of soils under cyclic loading, careful field observations of the nature, location and distribution of failures after earthquakes and detailed studies of individual failures.
The construction, design, remediation and maintenance of slopes have always formed an important area of geotechnical engineering which is often termed as 'slope engineering'. The wide variety of ...applications of slope engineering include excavations, hill roads, railway lines, embankments, earth dams, reservoirs, open-cut mines, urban development of hilly areas, protection of river banks and coastal slope stability. The study and analysis of slopes is essential for understanding their performance and, in particular, their stability, reliability and deformations. Thus geotechnical engineers often seek to calculate values of quantitative indicators of performance such as the factor of safety (safety factor), lateral deformation, and probability of failure and reliability index. Important concepts of geomechanics and, in particular, of soil mechanics have been vitally important for developing the basic mechanistic models of slopes and the associated methods of analysis, both simple and sophisticated. However, it is widely recognized that interdisciplinary approaches are required for a complete understanding of slope performance and for the choice of realistic models and methods of analysis for specific sites. Geoscientists have made significant contributions to the understanding of natural slopes, their evolution and performance over the long-term. To that end, they are concerned with modeling natural and other processes much more than considering specifics of stability analysis, slope design and remediation which are understood to be the main concerns of geotechnical engineers. However, the input of geoscientists is often valuable for slope engineering including the development, choice and use of mechanistic models. In fact, a geotechnical engineer would start detailed modeling after studying the geological report of a site and often after considering the specific observations made by an engineering geologist.
Before outlining and discussing methods of analysis, an overview of performance indicators will be useful. In the first chapter we have already referred, in general terms, to the conventional, ...site-specific approach of the geotechnical engineer involving mechanics (analysis of forces, stresses, strains), on the one hand, and the empirical or statistical regional approach of the geoscientist based on analysis and synthesis of observational data, on the other. Similarities and differences between these broad approaches, their strengths and limitations must be recognized. The need for an interdisciplinary approach for slope engineering which includes geotechnical slope analysis has also been emphasized. Thus it is always useful to consider a site specific analysis within the context of a regional analysis. Also, geological input is very useful in developing a geotechnical model for a slope analysis problem.
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