Geotechnical Know.How

GEO-SLOPE GeoStudio 2024.1.0.1406 [Size: 931 MB] ... GeoStudio is a product suite for geotechnical modeling and the vast geographic environment and to handle all your modeling needs. The GeoStudio suite includes the following products: SLOPE / W: Slope Stability Analysis - SEEP / W: Groundwater Summit Analysis - SIGMA / W: deformation pressure analysis - QUAKE / W: Dynamic earthquake analysis - TEMP / W: Geothermal Analysis - CTRAN / W: Solute Transfer Analysis - AIR / W: Airflow Analysis - VADOSE / W: Pro-Area Analysis and Soil Coverage.

GeoStudio Features: CAD slope stability software for calculating land and rock slope reliability coefficients. Effective Analysis of Simple and Complex Problems for Slip Surface, Water Pore Pressure, Soil Properties, Analysis Method, and Load Conditions + Groundwater analysis, pore pressure loss problems in porous materials such as soil and rock. + Perform stress analysis of the deformation of earth structures using SIGMA / W + Dynamic analysis of earthquakes to earthquakes or point to mechanical forces from an explosion or a sudden impact using the QUAKE / W tool + Analysis of thermal changes in land due to environmental factors or construction facilities such as buildings or pipelines using TEMP / W + Modeling the movement of pollutants through porous materials such as soil and rock + Analysis of groundwater and air interaction problems in soil and rock + Analysis of flow from the environment, across the surface, from the unsaturated fan zone to local groundwater.

 
Typical uses include: Math and computation + Algorithm development + Modeling, simulation, and prototyping + Data analysis, exploration, and visualization + Scientific and engineering graphics + Application development, including + Graphical User Interface building. MATLAB is an interactive system whose basic data element is an array that does not require dimensioning. This allows you to solve many technical computing problems, especially those with matrix and vector formulations, in a fraction of the time it would take to write a program in a scalar noninteractive language such as C or Fortran. The name MATLAB stands for matrix laboratory. MATLAB was originally written to provide easy access to matrix software developed by the LINPACK and EISPACK projects, which together represent the state-of-the-art in software for matrix computation. 

MATLAB has evolved over a period of years with input from many users. In university environments, it is the standard instructional tool for introductory and advanced courses in mathematics, engineering, and science. In industry, MATLAB is the tool of choice for high-productivity research, development, and analysis. MATLAB features a family of application-specific solutions called toolboxes. Very important to most users of MATLAB, toolboxes allow you to learn and apply specialized technology. Toolboxes are comprehensive collections of MATLAB functions (M-files) that extend the MATLAB environment to solve particular classes of problems. Areas in which toolboxes are available include signal processing, control systems, neural networks, fuzzy logic, wavelets, simulation, and many others.

Figure 1.  Silica and aluminum sheets

In nature, basically there are three types of clay minerals-namely, kaolinite clay, illite clay, and montmorillonite clay. These clays have different atomic structures and behave differently and are all made of two basic atomic sheets- namely, silica tetrahedral sheets and aluminum octahedron sheets, as seen in Figure 1. Naturally abundant atom silica (Si) and aluminum atom (Al) occupy the center positions of the sheets, and oxygen atom (O^2-) and hydroxyl (OH^-) are strongly bonded to those core atoms, respectively. These bonds are either ionic or covalent, and actual bonds in silica and aluminum sheets are combinations of these two types of bonds.

Note that the ionic bond is due to exchange of orbiting electrons of two atoms such as Na+ (sodium ion) and Cl^- (chlorine ion) to make NaCl (sodium chloride = salt), and the covalent bond is due to sharing electrons in their orbits such as two H⁺ (hydrogen ions) to form H₂ (hydrogen gas). These atomic bonds are very strong and can never be broken by ordinary physical forces. They are called the primary bonds.

A silica tetrahedral sheet is symbolized with a trapezoid, of which the shorter face holds electrically unsatisfied oxygen atoms and the longer face holds electrically satisfied oxygen atoms. An aluminum octahedron sheet is symbolized with a rectangle with top and bottom faces having the same characteristics of exposed hydroxyl (OH^-).

In most instances in nature, sheets are further bonded together, basically due to the unsatisfied face of a silica sheet to form various clay minerals.

Equation 1: G = γ_s/γ_w

γ_w is the unit weight of water and is 9.81 kN/m³ or 62.4 lb/ft³. The Geotechnical Standard specifies 20°C as the standard temperature for reporting the specific gravity.

Some qualifying words like: true, absolute, apparent, bulk or mass, etc., are sometimes added to the term ‘specific gravity’. These qualifying words modify the sense of specific gravity as to whether it refers to soil particles or to soil mass. The soil solids have permeable and impermeable voids inside them, the permeable voids being capable of getting filled with water. If all the internal voids of soil particles (permeable and impermeable) are excluded for determining the true volume of solids, the specific gravity obtained is called absolute or true specific gravity. The apparent or mass or bulk specific gravity G_m denotes the specific gravity of soil mass and is given by

Equation 2: G_m = γ/γ_w

Unless otherwise specified, we shall denote the Specific Gravity G (or G_s) (defined by Eq. 1) as the specific gravity of soil solids. Table 1 gives the values of specific gravity of some important soil constituents.

Table 1. Specific gravity of soil constituents

Most soils have a rather narrow range of G_s values: 2.65 to 2.70. This implies that solid particle is about 2.65 to 2.70 times heavier than the weight of water for the same volume. If a specific gravity test was not performed during the initial evaluation of geotechnical engineering problems, assuming G_s as a value between 2.65 or 2.70 would not produce a major error in the results.