Interdisciplinary Research Talk Series
by students & for students

Speaker: Melissa Haber’12

Date: April 6, 2011

Time and Place: 12:15pm; Hugel 103

Title: Increasing Sand Strength using Microbial Physiology

Advisers: Prof. Laurie Caslake (Department of Biology) and Dr. Jason DeJong (Department of Civil and Environmental Engineering, U.C. Davis)

Biomediated soil improvement can be used to strengthen weak or liquefiable sand deposits in geotechnical engineering. Liquefaction is defined as a rapid loss of strength and stiffness in saturated, loose, sand deposits. The simplest and most cost-effective method to strengthen soil is reinforcement or densification; these methods however can only be used at undeveloped sites due to their potential to cause severe damage to nearby buildings. At developed sites, the most common method involves injecting chemical grout into bore holes. The disadvantages of grouting include the high material costs and the difficulties associated with uniformly permeating the soil. An alternative to physical and chemical methods is a biological based method – using microbes to strengthen soil. Sporosarcina pasteurii, a microbe that performs ureolysis resulting in calcite deposition between sand particles, may be an option for bio-mediated soil treatment. We sought to determine the range of conditions that allow S. pasteurii growth, which is critical to the application of the bio-mediated soil treatment.

Sponsored by Lafayette Dean of The College, the Department of Computer Science, The Health and Life Science Program, and the National Science Foundation. Contact Person: Xiaoyan Li, Computer Science,, 610-330-5416