Methods for prevention of seepage due to excavation in sand (JTC sponsored project)
The soil improvements have to be done for enhancing its properties to match the engineering needs. The study adopts the usage of biocementation in sands in order to reduce the seepage effects by lowering the permeability in sands. Biocementation involves Microbial-Induced Calcium Carbonate Precipit...
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| Format: | Final Year Project (FYP) |
| Language: | English |
| Published: |
2018
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| Online Access: | http://hdl.handle.net/10356/74926 |
| Summary: | The soil improvements have to be done for enhancing its properties to match the engineering needs. The study adopts the usage of biocementation in sands in order to reduce the seepage effects by lowering the permeability in sands.
Biocementation involves Microbial-Induced Calcium Carbonate Precipitation (MICP) reaction which precipitates calcium carbonate on the voids in the sand so that the permeability of sands and seepage effect could be lessened. This method is also environment friendly compared to other kinds of grouting such as chemical grouting because there are no heavy metals but only common bacterias and chemicals. Urease-producing Bacteria (UPB) is used in MICP reaction to increase the rate of hydrolysis of urea. The seepage problems in two different types of embedded walls (permeation grouting wall and sheet pile wall) are countered by two types of method (Double Tubes Grouting Method and Single Tube Grouting Method).
The seepage effect had been reduced effectively up to 96.1% after several occasions of treatments. The hydraulic coefficient of column samples are lowered to 1 x 10-7m/s. Besides, other properties such as the strength of the treated sands are also improved significantly. |
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