A Review on Enhanced Stability Analyses of Soil Slopes Using Statistical Design

This chapter deals with the application of experimental design in slope stability analysis. In particular, focus of the present chapter is on the application of Box-Behnken statistical design for assessment of stability of slopes in homogeneous soil (general case), for estimation of slope stability in clay-marl deposits at the edge of Neogene basins (case study) and for the extension of grid search method for locating the critical rupture surface. Extensive statistical analysis, internal and external validation imply high estimation accuracy and reliability of developed mathematical expressions for slope safety factor and for parameters of location of critical rupture surface. Main advantages and limitations of the proposed approach are thoroughly discussed with suggestions for main directions of further research.

A New Acoustic Energy-Based Method to Estimate Pre-Loads on Cored Rocks

The Acoustic Emission (AE) due to the sudden release of energy from the micro-fracturing within the rock under loading has been used to estimate pre-load. Once the pre-load is exceeded an irreversible damage occurs at which AE signals significantly increase. This phenomenon known as Kaiser Effect (KE) can be recognised as an inflexion point in the cumulative AE hits versus stress curve. In order to determine the value of pre-load (sm) accurately, the curve may be approximated by two straight lines. The intersection point projected onto the stress axis indicates the pre-load. However, in some cases locating the point of inflexion is not easy. To overcome this problem we have developed a new method, The University of Adelaide Method (UoA), which use cumulative acoustic energy. Unlike existing methods, the UoA method emphasises the energy of each AE, the square term of the amplitude of each AE. As the axial pre-load is exceeded, the micro cracks become larger than the existing fractures and therefore energy released with new and larger cracks retain higher acoustic energy.

Prediction of The Uniaxial Compressive Strength of Rocks Materials

This study briefly will review determining UCS including direct and indirect methods including regression model soft computing techniques such as fuzzy interface system (FIS), artifical neural network (ANN) and least sqeares support vector machine (LS-SVM). These has advantages and disadvantages of these methods were discussed in term predicting UCS of rock material. In addition, the applicability and capability of non-linear regression, FIS, ANN and LS-SVM SVM models for predicting the UCS of the magnatic rocks from east Pondite, NE Turkey were examined. In these soft computing methods, porosity and P-durability secon index defined based on P-wave velocity and slake durability were used as input parameters. According to results of the study, the performanc of LS-SVM models is the best among these soft computing methods suggested in this study.

Intelligent Models Applied to Elastic Modulus of Jointed Rock Mass

Elastic Modulus (Ej) of jointed rock mass is a key parameter for deformation analysis of rock mass. This chapter adopts three intelligent models {Extreme Learning Machine (ELM), Minimax Probability Machine Regression (MPMR) and Generalized Regression Neural Network (GRNN)} for determination of Ej of jointed rock mass. MPMR is derived in a probability framework. ELM is the modified version of Single Hidden Layer Feed forward network. GRNN approximates any arbitrary function between the input and output variables. Joint frequency (Jn), joint inclination parameter (n), joint roughness parameter (r), confining pressure (s3) (MPa), and elastic modulus (Ei) (GPa) of intact rock have been taken as inputs of the ELM, GRNN and MPMR models. The output of ELM, GRNN and MPMR is Ej of jointed rock mass. In this study, ELM, GRNN and MPMR have been used as regression techniques. The developed GRNN, ELM and MPMR have been compared with the Artificial Neural Network (ANN) models.

Soil Liquefaction Assessment by Anisotropic Cyclic Triaxial Test

Liquefaction of saturated sandy soils is one of the most significant aspects of earthquake triggered natural hazards. The main mechanism deals with the loss of effective stress due to rapid pore water pressure generation during earthquake shaking. This chapter involves with the fundamental mechanism and impacts of liquefaction. Liquefaction susceptibility of geological environments are briefly represented for preliminary assessment. Standard procedures of liquefaction are summarized. The dynamic response of sands are also reviewed. A case of anisotropic loading is considered, using three different particle sized sands below a shallow footing. Such sandy soils are subjected to anisotropic consolidation before performing undrained cyclic triaxial testing along limited cycles. Variation of axial strain, pore water pressure and related parameters are investigated. Main outcome of this study is to review the initial liquefaction state of sands by anisotropic loading case.

Integration Between Urban Planning and Natural Hazards For Resilient City

Analyses and syntheses conducted before the urban planning process are significant. Accurate analysis and synthesis enable to determine proper site selection and the proper site selection is the basis of a sustainable urban plan. In this sense, fundamental analysis inputs of the proper site selection could be indicated as the related parameters of the earth sciences. The interpretation of these inputs require the essential analyses and syntheses of initially the geological and geotechnical research with geophysics, tectonic, topography, mineral and natural resources, hydrogeology, geomorphology and engineering geology. Synthesis maps composed of these inputs especially provide guides for natural thresholds consisting of landslide, flood, inundation, earthquake etc. for land use planning and site selection parts in the urban planning processes. In this regard, this chapter of the book contains the relation between the earth sciences parameters with the urban planning and the way these parameters lead the way of urban planning processes.

Slope Stability of Soils

Slope stability problems in soils underlie most of the landslides that cause losses of human and property in the world. The stability of natural or man-made slopes in soils is an important topic that requires great attention while site exploring, testing, modelling and analyzing. Engineering geology and geotechnical engineering interdisciplinary team work is essential to achieve a sufficient understanding of site geology and the behavior of soil. The developments of urban areas require new sites for settlement. Soil structure interaction in slopes requires more sophisticated numerical analysis methods to develop. This section particularly summarizes the factors cause a slope to fail. In addition, site exploration steps, in-situ and laboratory test methods were mentioned. Slope stability analysis methods such as LEM, FEM, DEM, BEM were discussed in details. The developments of empirical or statistical regional approaches were stated. Remediation techniques were discussed regarding the construction costs. Finally, the necessity of further studies in numerical modelling was emphasized.

Seismic Microzonation and Site Effects Detection Through Microtremors Measures

Seismic microzonation of a city can be a difficult and expensive undertaking depending on the method used. In the last years, the HVSR method has been one of the most popular ways to define the natural frequency of the soil and seismic amplification factor in order to make quick microzonations due to that it is an expeditious and cheap method. This is very important in developing countries and poor countries. The fundamental reason to use this method is the fact that the amplification factor has well correlation with damage distribution. Additionally with the help of another methods it is possible obtain the structure of the superficial soil strata. In this chapter, an introduction with seismic microzonation, site effects concepts, microtremors, description of the HVSR method, advantages and disadvantages of this method, limitations and comparison with other methods, are presented. Finally, highlight of the importance of the method in order to identify site effects are displayed as examples and the incorporation of these data to Geographic Information Systems is also shown.

Geophysical Surveys in Engineering Geology Investigations With Field Examples

This chapter focusses on geophysical survey techniques, employed in engineering geological investigations and it includes case studies. Goal of a geophysical study in an engineering geological research is to display discontinuities in the rock masses, physico-mechanical properties of soils and rocks, groundwater exploration, faults, landslides, etc. It is also helpful to learn type and thickness of soil, layer inclination. These techniques include engineering geological surface mapping, geotechnical drilling and in situ testing.Then the obtained geophysical field data are analyzed and interpreted in conjunction with the results of geological information.The most common geophysical methods namely seismic, magnetometric, vertical electrical sounding (VES), Very Low Frequency (VLF) Electromagnetics methods, ground penetration radar (GPR) provide sufficient information about the subsurface although they have their limitations, setting up the minimum tests requirements in relation to the type of the geological formations.

Excavatability Assessment of Rock Masses for Geotechnical Studies

The excavatability of rocks is of importance for the selection of suitable and cost–effective excavation methods not only in mining and quarrying but also in the construction of tunnels, subways, highways and dams. Moreover, selection of the right excavation method and equipment in mining and geotechnical projects depends on the excavatability properties of rocks. A number of different methods have been proposed to evaluate the excavatability of rocks based on their geotechnical properties, such as rock mass rating (RMR), uniaxial compressive strength (UCS), discontinuity spacing of rock masses, point load index (PLI) and seismic velocity of intact rock. The type of equipment used and the method of working also affect the excavatability of rocks. In this work, the term excavatability is considered as the ease of excavation of rock and rock masses and comprises the methods of digging, ripping, breaking and blasting for easy/very easy, moderate to difficult, soft or moderately to highly fractured rock and very difficult excavation conditions, respectively.