BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Applicability of Microbially Induced Calcite Precipitation (MICP) 
 for Soil Treatment - Osama Dawoud\, CUED
DTSTART:20140605T150000Z
DTEND:20140605T160000Z
UID:TALK52686@talks.cam.ac.uk
CONTACT:Anama Lowday
DESCRIPTION:Microbially Induced Calcite Precipitation (MICP) is a recently
  developed technique for soil improvement. MICP is forging ahead demonstra
 ting its efficiency and advantages as an alternative for the traditional t
 echniques. The distinctive characteristic of the MICP is the in-situ occur
 rence of the precipitation reaction. Soil treatment with MICP involves int
 roducing a specific biological activity of the soil before injecting a sta
 ble urea solution with a calcium source. The biological activity catalyzes
  the hydrolysis of urea introducing carbonate ions that lead to the precip
 itation of the calcite. The precipitated calcite binds the soil particles 
 together and clogs the pores changing the engineering characteristics of t
 he soil.\n\nThe optimization of the MICP process became possible on the co
 ntrolled lab-scale experiments. Nevertheless\, the applicability of the MI
 CP on the field-scale is still determined by some common natural condition
 s like high pore-water pressure\, nonuniform flow fields\, and soil hetero
 geneity that have not received sufficient investigation yet. This study is
  focused on the assessment of MICP under these conditions in terms of the 
 precipitation efficiency and the uniformity of precipitation profiles. Thi
 s assessment was carried out employing a modified flexible-wall permeabili
 ty test to allow for continuous monitoring of soil stiffness (represented 
 as by shear wave velocity) and hydraulic conductivity. In addition\, an up
 scaled radial model was used to resemble the radial flow systems used for 
 the treatment in the field. The radial model was used also to study the MI
 CP in heterogeneous soils. As the uniformity of precipitation is considere
 d one of the major challenges in the field\, the study investigated the us
 e of surfactants for the improvement of MICP profiles.\n\nThe development 
 of soil characteristics by MICP treatment was found to follow a phased gen
 eral trend that has several implications for the applicability of MICP in 
 the field. The feasibility of MICP for different geotechnical applications
  was revised based on this trend of change and the possible degrees of con
 trol. Implications for the field were also interpreted based on the correl
 ations between precipitation profiles and the flow-fields. This study prop
 oses a design approach for MICP treatment systems that is based on the ini
 tial hydrological system of the site defining a critical minimum seepage v
 elocity as the main design parameter. This approach could serve the design
  purposes better than the comprehensive numerical modeling of the treatmen
 t process which is still facing obstacles due to the complexity of the inv
 olved processes in MICP.\n
LOCATION:Engineering Department - Lecture Room 3B
END:VEVENT
END:VCALENDAR