CAREER: Linking Rheology to Performance - An Integrated Approach to the Evaluation and Design of Trenchless Technology Fluids

Purdue University, West Lafayette IN

Investigators

Abstract

Abstract: This research addresses the topic of the design and evaluation of fluids employed in trenchless technology (microtunneling, pipejacking, and horizontal directional drilling). These fluids play a critical role in the construction and rehabilitation of underground utility infrastructures, the total length of which is estimated to exceed 35 million miles in the US alone. With deferred maintenance costs for water and wastewater alone assessed at more than $100 Billion/year, techniques that can extend the reach of the construction and rehabilitation dollar have significant value. Paramount to the success of all trenchless technologies is the use of a fluid which serves four critical functions: lubrication; cake formation and filtration control; spoil/cutting transport; and soil conditioning. For optimal selection/design of these fluids all these aspects of performance must be considered simultaneously in an integrated manner. The focus of this research is to develop an integrated approach to the design and evaluation of fluids used in trenchless technology. The work is founded on a fundamental investigation of the rheological properties of a variety of fluids performed using state-of-the-art equipment and methodologies. The emphasis of the research is primarily on bentonite based fluids, both ?pure? as well as treated with the compounds (polymers of different types, surfactants, waxes, micro-beads) that are used to enhance their properties. However, on a secondary basis select polymeric fluids will also be investigated. In conjunction with the rheological tests, the experimental program includes experiments designed to evaluate the performance of the fluids in the four primary functions described, under conditions representative of those occurring in the field, for direct correlation to the rheological data. Microstructural observations of the fluids in their hydrated state through state of the art SEM equipment with cryo-unit, will provide the means to link observed behavior to microstructure. The educational activities have a direct tie to the research and are designed to benefit a large audience including K-12 students and college freshmen. In particular, the research will see the direct involvement of a team of undergraduate students in support of the research activities through participation in an innovative design based course. The proposal contains a plan for recruiting women and underrepresented minorities to civil engineering and increasing their involvement in research.