EAS Doctoral Proposal Defense
by Danilo Gianni Zeppilli
Date: Monday, August 22, 2022
Time: 10:00 a.m.
Topic: The Behavior of Crushable Problematic Calcareous and Glauconitic Soils
Zoom Teleconference:
https://umassd.zoom.us/j/92794428421?pwd=M20vYnBaWGREOFJZNUx2RkJWNXRMUT09
Abstract:
Soil is primarily composed of solid particles created by weathering, but commonly found in our coastal zones are soils which are made of particles with internal voids created by biologic influence. Two soils of such nature are Calcareous and Glauconitic marine sediments. Calcareous soils are made of Calcium Carbonate and are formed when biologic organisms in the ocean such as foraminifera, algae, coral, and mollusks die and discard their shells or tests or through precipitation which then make its way to the ocean floor. Due to their hollow nature these sediments have various densities depending on their particle size while sand-sized particles have lower densities than fine-grained particles. Glauconitic soils are made of iron and potassium, have internal cracks and fissures, and begin forming in marine and estuarine environments at the water-soil boundary. These two types of soils are fragile and brittle in nature due to their internal voids and can lead to many problematic behaviors during construction. When calcareous soils are loaded through pile driving and foundation construction, pile running, and increased compressibility are expected responses that must be carefully considered. Where glauconite soils are concerned particle breakage leads to pile driving resistance and decreases in bearing capacity as well as adhesion to piles upon their removal. This proposed dissertation research aims to investigate properties of these two problematic soils and determine the mechanisms behind their concerning responses.
The first chapter of this proposed research will investigate the crushing of sands containing voids within the particles and the trends of void ratio and particle size evolutions during compression. This chapter aims to determine differences between hollow and solid soil crushing. The second chapter will look at the differences in specific gravity, particle sizes, plasticity, and shearing behaviors between uncrushed and crushed glauconitic soils. This will aid in insight on classifying these soils and their behaviors during pile driving and loading. Chapter three will look at differences in the transitional fines content (TFC) of a soil which has a variation in density between coarse- and fine- grained particles through hydraulic and compressive behavior. The TFC of typical soils is around 30% fine grained particle, and it is suspected that when the fines portion has a higher specific gravity, this content will be lower. Finally, the fourth chapter will investigate the triaxial compression of a sand containing hollow fragile particles. This chapter will utilize X-Ray micro computed tomography (CT) to track the compression and crushing of hollow particles when consolidation and shear compression occurs. Through these four chapters, the mechanical responses of several brittle and crushable soils which contain internal void space will be investigated to aid in determining classification of these problematic soils.
ADVISOR(S): Dr. Ryan Beemer, Department of Civil and Environmental Engineering
(rbeemer@umassd.edu, 508.999.8416)
COMMITTEE MEMBERS: Dr. Daniel MacDonald, Civil and Environmental Engineering
Dr. Walaa Mogawer, Civil and Environmental Engineering
Dr. Cynthia Pilskaln, SMAST/Estuarine & Ocean Sciences
Dr. Santiago Quinteros, Norwegian Geotechnical Institute
NOTE: All EAS Students are ENCOURAGED to attend.
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