Tech Writing Lab Report
Dr. Clinton Lanier
Written by: Jon Leyba
Date Assigned: 10/17/2011
Date Due: 10/24/2011
The purpose of his lab is to perform a sieve analysis on a sample of soil collected near the EMRTC facility behind the New Mexico Tech Campus. The soil sample has reddish fines, sand, and gravel. The grain size distribution (GSD) test is used for soil classification, under the Unified Soil Classification System (USCS). The USCS is considered to be the best classification method for soils. The GSD test can be used to estimate the mechanical properties of a soil. The data collected will be used to plot a GSD curve. The GSD curve is plotted in log scale to show small changes and details that a normal scale would lose. Based off of the GSD curve we can then calculate the Coefficient of Uniformity (Cu) and the Coefficient of Curvature (Cc). These coefficients are the standards in the USCS to classify if a soil is poor or well graded. How well a soil is graded determines how well the soil will compact for foundations.
Lab Procedure followed - ASTM D422
The American Society of Testing and Materials (ASTM) is widely used and highly trusted procedure system. ASTM D422 describes in detail how to specifically perform the lab. Basically a certain amount of soil is put on top a stack of sieves arranged by largest openings on top and smallest towards the bottom. A pan is at the bottom to collect passing soil. The sieves are vibrated by a machine for some amount of time to allow the fine particles to move on to the next sieve. A diagram of sieves is shown in FIGURE 1. Also, TABLE 1 displays sieve numbers and the diameter openings as they were stacked in the lab.
FIGURE 1: Diagram showing soil sifted in sieves
TABLE 1: Relationship between sieve numbers and sieve openings
US Standard Sieve No.| Sieve Opening (mm)| Sieve Opening (in) | #4| 4.75| .187|
#10| 2.0| .0787...