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300 Solved Problems Soil / Rock Mechanics and Foundations Engineering These notes are provided to you by Professor Prieto-Portar, and in exchange, he will be grateful for your comments on improvements. All problems are graded according to difficulty as follows: * Easy; defines general principles; typical of the PE examination; ** Slightly more difficult; typical of Master s level problems; *** Professional level ( real-life ) problems. by Luis A. Prieto-Portar PhD, PE Professor of Civil and Environmental Engineering Florida International University, Miami, Florida Former Professor, United States Military Academy (West Point) Telephone / Fax Website: Copyright by L. Prieto-Portar, October, 009 ii

2 Table of Contents Table of Contents… i Chapter 1 Soil Exploration… 1 Symbols for Soil Exploration… 1 *Exploration 01. Find the required number of borings and their depth…. *Exploration 0. The sample s disturbance due to the boring diameter…. *Exploration 0. Correcting the SPT for depth and sampling method *Exploration 04. Three methods used for SPT depth corrections… 6 *Exploration 05. SPT corrections under a mat foundation *Exploration 06. The Shear Vane Test determines the in-situ cohesion… 9 *Exploration 07. Reading a soil boring log *Exploration 08: Using a boring log to predict soil engineering parameters **Exploration 09. Find the shear strength of a soil from the CPT Report Chapter Phase Relations of Soil Symbols for Phase Relations of soils Basic Concepts and Formulas for the Phases of Soils *Phases of soils-01: Convert from metric units to SI and US units *Phases of soils 0: Compaction checked via the voids ratio…. *Phases of soils 0: Value of the moisture when fully saturated…. *Phases of soils 04: Finding the wrong data *Phases of soils 05: Increasing the saturation of a soil *Phases of soils 06: Find γ d, n, S and W w *Phases of soils 07: Use the block diagram to find the degree of saturation *Phases of soils 08: Same as Prob-07 but setting the total volume V=1 m *Phases of soils 09: Same as Problem #5 with a block diagram… 9 *Phases of soils 10: Block diagram for a saturated soil *Phases of soils 11: Find the weight of water needed for saturation *Phases of soils 1: Identify the wrong piece of data…. *Phases of soils 1: The apparent cheapest soil is not!… *Phases of soils 14: Number of truck loads *Phases of soils 15: How many truck loads are needed for a project?… 5 *Phases of soils 16: Choose the cheapest fill supplier i

3 *Phases of soils 17: Use a matrix to the find the missing data… 8 **Phases of soils 18: Find the voids ratio of muck (a highly organic soil) Chapter Classification of Soils and Rocks Symbols for Classification of soils *Classify 01: Percentage of each of the four grain sizes (G, S, M & C)… 4 *Classify 0: Coefficients of uniformity and curvature of granular soils *Classify-0: Classify two soils using the USCS *Classify-04: Manufacturing a new soil Classify Classify Classify Classify Classify Classify Classify Chapter 4 Compaction and Soil Improvement Symbols for Compaction *Compaction 01: Find the optimum moisture content (OMC) *Compaction 0: Find maximum dry unit weight in SI units *Compaction-0: What is the saturation S at the OMC? *Compaction-04: Number of truck loads required *Compaction-05: What is the saturation S at the OMC?… 6 *Compaction-06: Definition of the relative compaction (RC)… 6 *Compaction-07: The relative compaction (RC) of a soil *Compaction-08: Converting volumes from borrow pits and truck loads **Compaction-09: Ranges of water and fill required for a road **Compaction-10: Find the family of saturation curves for compaction **Compaction-11: Water needed to reach maximum density in the field **Compaction-1: Fill volumes and truck load requirements for a levee **Compaction-1: Multiple choice compaction problem of a levee Chapter 5 Permeability of Soils Symbols for Permeability *Permeability 01: Types of permeability tests and common units ii