NSF Award
2401559
Research funded by this award aims to enhance current understanding of the compaction of granular soils, a critical construction process for many civil infrastructure systems. Compaction is the most common method of soil improvement for these soils. Yet, traditional compaction often relies heavily on engineering experience and post-construction quality control, leading to under or over-compaction problems in the field. This research project will provide new insights into the effects of granular soil properties and compaction equipment characteristics on compaction efficiency, which may lead to more efficient construction practices and reduced carbon footprints of civil infrastructure systems. This project is a collaborative effort between two Penn State campuses, Altoona, primarily an undergraduate institution, and University Park, a research institution. It will provide substantive research experiences to undergraduate students from Altoona, exposing them to contemporary knowledge such as sensing technology and data transmission. These experiences will enrich the engineering curricula at both campuses. In particular, the improved curriculum will benefit the Rail Transportation Engineering program at Penn State – Altoona, the nation’s first and only four-year bachelor’s degree program in railroad transportation.<br/><br/>The central hypothesis of this research is that particle kinematics can be used as a proxy of soil compaction, rather than surface settlement, to study the state of compaction in granular soils. This hypothesis will be tested through an integrated experimental and numerical investigation. The project will involve laboratory compaction tests, which will be instrumented with geophones, accelerometers, a linear variable differential transducer, and a load cell; these instruments will record the dynamic response of soil in the compaction zone and the reaction force to the compactor due to soil-compactor interaction. In particular, wireless sensing devices, SmartRocks, will be embedded at various locations in the compaction zone to record the evolution of particle kinematics (e.g., acceleration and rotation) during compaction. The compaction test results will be used to calibrate and validate a computing model based on the idea of fusing SmartRock measurements and discrete element simulations to increase the accuracy of the simulations. The validated computing model will be used to extend the insights gained from the laboratory tests to field conditions that resemble the compaction of a moving vibratory roller compactor. This research will, for the first time, yield insights into the effect of granular soil properties, equipment characteristics, and operating frequency on the particle kinematic behavior (e.g., rotation, acceleration, and contact stress) in different zones during compaction.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
