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Li, B. (2015). Geotechnical properties of biocement treated sand and clay. Doctoral thesis, Nanyang Technological University, Singapore. Retrieved from https://hdl.handle.net/10356/62560 Li Bing, associate professor of Civil and Environmental Engineering at Nanyang Technological University is the author of this investigation on the potential uses of biocement on low permeable material. This article focused on the application of biocement to improve the soil conditions for geotechnical engineering. In this research project, its aim is to use microbial technologies to study biocementation effects on low permeability materials such as clay. Microbially induced calcium carbonate precipitation (MICP) is the most practiced biocementation method. The properties of MICP treated soil were tested with various tests. For instance, unconfined compression tests, triaxial tests and direct simple shear tests. The article also mainly uses three sets of bacteria for this experiment. They are U...

Introduction 1.1 Background Information This proposal has been reported in response to the request for developing engineering solutions to strengthen soil to prevent differential soil settlement under structures. With the Singapore government turning to underground spaces to reduce land demand in Singapore, one can expect the number of underground works to increase. However, underground works have been synonymous with damages to nearby existing structures. This is due to differential soil settlement, a phenomenon that occurs when the soil settles at a different rate. If this happens under a structure, cracks can occur on the structure due to uneven distribution of loading into the soil. This can cost the contractor resources as compensation may be required. To prevent such issues from worsening, measures such as soil strengthening can be put in place when identified. One such soil strengthening method can be to cycle a solution of calcium and biocementation bacteria across the f...

In the web article “I-5 and the Physics of Bridge Collapses”, Hartsfield (2013) claimed that the concept behind a functional bridge design is what leads to its failure as well. The article examined the various types of bridges and found that the different types of bridges have weaknesses specific to themselves.  One such example stated by the article is that truss bridges, which use geometric shapes as a basis for its strength and stability. As such, it is claimed by the article that deformations on the shape will cause the bridge to fail.  Suspension bridges fail due to its inability to withstand huge external forces. The article observed that “when an external force causes the bridge to vibrate at its resonant frequency, it causes the vibration to grow stronger and stronger”. Another example of such a phenomenon are cantilever bridges. The article alleged that cantilever bridges are designed to be able to withstand the torque that the lever arm takes, yet failures are f...

In the web article “I-5 and the Physics of Bridge Collapses”, Hartsfield (2013) claimed that the concept behind a functional bridge design is what leads to its failure as well. The article examined the various types of bridges and found that the different types of bridges have weaknesses specific to themselves. One such example stated by the article is that truss bridges, which use geometric shapes as a basis for its strength and stability. As such, it is claimed by the article that deformations on the shape will cause the bridge to fail. Suspension bridges fail due to its inability to withstand huge external forces. The article observed that “when an external force causes the bridge to vibrate at its resonant frequency, it causes the vibration to grow stronger and stronger”. Another example of such a phenomenon are cantilever bridges. The article alleged that cantilever bridges are designed to be able to withstand the torque that the lever arm takes, yet failures are found to be due...

In the web article “I-5 and the Physics of Bridge Collapses”, Hartsfield (2013) claimed that the concept behind a functional bridge design is what leads to its failure as well. The article examined the various types of bridges and found that the different types of bridges have weaknesses specific to themselves.  One such example stated by the article is that truss bridges, which use geometric shapes as a basis for its strength and stability. As such, it is claimed by the article that deformations on the shape will cause the bridge to fail.  Suspension bridges fail due to its inability to withstand huge external forces. The article observed that “when an external force causes the bridge to vibrate at its resonant frequency, it causes the vibration to grow stronger and stronger”. Another example of such phenomenon are cantilever bridges. The article alleged that cantilever bridges are designed to be able to withstand the torque that the lever arm takes, yet failu...

In the web article “I-5 and the Physics of Bridge Collapses”, Hartsfield (2013) claims that the concept behind a functional bridge design is what leads to its failure as well. Truss bridges “are composed of steel beams in the shape of triangles”. According to the article, triangles are used for truss bridges as its shape cannot distort without a beam or joint failure. It is observed by Hartsfield that corner and beam failures are the underlying causes for most truss bridges. Suspension bridges are built by hanging huge cables from “tower to tower” with smaller ones hanging straight down and fix on the road deck at the side. However, the failure of suspension bridges is mainly due to its design as well because it is not designed to withstand huge external force. Hartsfield states that “when an external force causes the bridge to vibrate at its resonant frequency, it causes the vibration to grow stronger and stronger.” This means that the design of the suspension bridge is also t...