CEEN Geotechnical Engineering

Transcription

1 CEEN Geotechnical Engineering Lab Report 1 Soil Classification prepared by Student Name 1 Student Name 2 Student Name 3 Student Name 4 Tuesday Lab Time 9:30 10:45 Lab Team 1 Submission Date

2 INTRODUCTION This report presents the results of a soil sampling and analysis conducted following procedures provided by the American Society for Testing and Materials (ASTM). All tests reported herein were conducted in the Marquette University Soil Laboratory. SUMMARY OF TESTS CONDUCTED A soil sample was obtained within the Marquette University Soils Pit using a portable Geoprobe tube sampler. The soil was visually classified and soil tests were conducted on a representative sample of the obtained clay soil which was dried and pulverized prior to testing. Lab tests included a dry sieve analysis (ASTM D422), a hydrometer analysis (ASTM D422), specific gravity of solids (ASTM D854) and Atterberg limits (ASTM D4318). Collected laboratory data and sample calculations are provided in Attachments 1-4. SUMMARY OF RESULTS OBTAINED A summary of the grain size distribution of the soil is provided in Table 1 and Figure 1. Table 2 provides a summary of the specific gravity and Atterberg limits for this soil. The data provided in Table 1 was obtained by combining the results of both the dry sieve analysis and the hydrometer analysis, as represented by the solid particle-size distribution curve presented in Figure 1. Table 1 - Grain Size Distribution of Soil U.S. Standard Sieve Number Grain Size (mm) Percent Passing (by weight) (1) 3/ No No No No No No D 10 = mm, D 30 = mm, D 60 = mm, Cu = 193, Cc = (1) Based on combined results of the dry sieve and hydrometer tests 1

3 Figure 1: Grain Size Distribution of Clayey Soil Table 2 Summary of Specific Gravity and Atterberg Limits Soil Property Test Result Specific Gravity of Soil Solids 2.58 Liquid Limit 32 Plastic Limit 17 Plasticity Index 15 2

4 Soil Classifications Soils are generally classified based on their particle-size distribution and Atterberg limits. In some instances, only the particle-size distribution is required. Table 3 presents the relative proportions of gravel, sand, silt and clay sized particles contained in this soil following the guidelines presented by the United States Department of Agriculture (USDA), the American Association of State Highway Transportation Officials (AASHTO), and the Unified Soil Classification System (USCS). Table 3 Approximate Soil Size Fractions System % Gravel %Sand %Silt %Clay USDA Modified USDA (1) AASHTO USCS (2) (1) Modified USDA excludes Gravel Fraction (2) Silt & Clay Fraction not differentiated by USCS Based on the USDA textural classification chart this soil would be classified as a loam. This classification is further modified due to the gravel content, which lies between 15 and 50 percent, resulting in a USDA soil classification of a gravelly loam. The AASHTO classification system generally relies on both the particle-size distribution and the Atterberg limits of the soil. This particular soil would be classified as a fine-grained soil (%Silt & Clay = 48; P 200 > 35). Given the liquid limit and plasticity index values of 32 and 15, respectively, this soil falls within the A-6 soil classification group and would be considered as a clay of low compressibility. The Group Index is calculated as 19, yielding an AASHTO classification of A-6 (19). The USCS classification system generally relies on both the particle-size distribution and the Atterberg limits of the soil. This particular would be classified as a coarse-grained sandy soil (%Silt & Clay = 48; P 200 < 50 and %S > %G). Given the liquid limit and plasticity index values of 32 and 15, respectively, the soil fines fall within the CL region and would be considered as clays of low compressibility. Considering the gravel content, this soil would result in a USCS classification of an SC, clayey sand with gravel. DISCUSSION Use your own words to describe the lessons learned and sources of possible errors. 3

5 ATTACHMENT 1 Soil Boring Profile

6 ATTACHMENT 2 Grain Size Distribution Data

7 ATTACHMENT 3 Specific Gravity of Soil Solids Data

8 ATTACHMENT 4 Atterberg Limits Data