Influence of Mt. Mazama Volcanic Ash on the Optimal Water Content for Compaction of a Soil from a Residential Development in Cheney, WA
Faculty Sponsor
Richard Orndorff, Eastern Washington University
Research Project Abstract
We tested soil from the Harvest Bluff (HB) development in Cheney, WA, which sits between loess hills to the north and the Four Lakes Ice Age flood path to the south. We also tested Mazama ash (5677 BC), which is abundant in the Spokane-Cheney region, to assess the impact of volcanic ash on soil compaction properties. HB soil is classified as low liquid limit silt, and Mazama ash is classified as non-plastic silt. We determined optimal water content for compaction to be 16% with a maximum dry unit weight of 101 pcf for HB soil, 41% and 64.8 pcf for Mazama ash, and 31% and 79.9 pcf for a 50% mixture by weight. This test reveals the amount of water necessary to maximize grain-to-grain contact within soil during compaction, which correlates with enhanced compressive strength. Addition of ash increases optimal water content for compaction and decreases maximum unit dry weight.
Session Number
PS2
Location
Graves Gym
Abstract Number
PS2-s
Influence of Mt. Mazama Volcanic Ash on the Optimal Water Content for Compaction of a Soil from a Residential Development in Cheney, WA
Graves Gym
We tested soil from the Harvest Bluff (HB) development in Cheney, WA, which sits between loess hills to the north and the Four Lakes Ice Age flood path to the south. We also tested Mazama ash (5677 BC), which is abundant in the Spokane-Cheney region, to assess the impact of volcanic ash on soil compaction properties. HB soil is classified as low liquid limit silt, and Mazama ash is classified as non-plastic silt. We determined optimal water content for compaction to be 16% with a maximum dry unit weight of 101 pcf for HB soil, 41% and 64.8 pcf for Mazama ash, and 31% and 79.9 pcf for a 50% mixture by weight. This test reveals the amount of water necessary to maximize grain-to-grain contact within soil during compaction, which correlates with enhanced compressive strength. Addition of ash increases optimal water content for compaction and decreases maximum unit dry weight.
