Sensors Measure Soil Settlement for Safer Construction Site Regions
A pile driver is a mechanical device used to drive piles - or poles - into soil to provide foundation support for buildings or other structures. Vibrations from pile driving can create cracks in deep foundations for nearby structures like bridges. University of Michigan researchers are hoping a new sensor can predict soil settlement before an accident occurs. Ground surface sensors have traditionally been used to measure the vibrations, but the length needed to travel from deep underground in order to reach the sensors is telling only part of the story. Adda Athanasopoulos-Zekkos, assistant professor of Civil and Environmental Engineering at the University of Michigan, is taking a different approach by installing both geophones and accelerometers in depth and very close to the driven pile. This has given her team data that is first of its kind and will hopefully lead to a better understanding of how much soil settlement is produced in a construction site.
Transcript
00:00:01 So we're looking into understanding better vibrations that are induced during pile driving for deep foundations, for bridges and structures. Most of the bridges in the state of Michigan are founded on shallow foundations and these vibrations might interfere with the existing bridges because the existing piers are very close to the new ones. There was actually a bridge that sustained some cracking because of these pile driving operations a lot of piles take thousands if not tens of thousands of impacts to be driven to the depth that's required for that specific structure. That has definitely piqued the interest in better understanding these
00:00:40 vibrations. Vibrations have up to this point been measured using sensors that are placed on the surface on the ground these vibrations have to travel from very deep into the ground to reach the surface so the type of vibrations we recorded on the surface are important and they do help us tell part of the story but they can't help us tell the entire story. What we have done for the first time is install sensors, accelerometers and geo phones in-depth and very close to the driven pile.
00:01:13 This has given us data that's first of it's kind. So in the lab we tried to create under controlled environments the same conditions that we would have in the fields. We use the same sensors, the same techniques, of course reduced in scale since we're indoors in a lab. When piles are being driven it means that there's a wider project at hand so there are other activities going on at the same time so that creates an additional challenge when we're bringing the data back into the office and trying to understand really what it means this kind of collection in the lab not only helps us
00:01:47 eliminate some these challenges it will help us understand some on the phenomena in the signals in the data that we are collecting then we can actually use the data in the field and be smarter about how we use and synthesize. So the next step on the research that's very critical would be going from understanding what type of soil is susceptible to this shakedown settlement to being able to compute how much that settlement would be. That's what everybody's asking for and that's very complicated problem to solve but one that we feel this research has
00:02:22 definitely made the first step towards. Related Video: Mercury basically is a neurotoxin it effects neurological development of fetuses and infants and in very very high concentrations it can affect the neurological functioning of adults.