Performing ground vibration monitoring is essential to reduce the risk of construction or mining work harming structures or areas close by to a work site. These standards were developed by the Office of Surface Mining Reclamation and Enforcement which created a nationwide set of criteria to regulate environmental damage caused by coal mining.
Ground vibration monitoring regulations vary from state to state as different governments establish laws based on their land and its requirements. When conducting work in the state of California, it is important to follow state, federal and local laws. Below we explore ground vibration monitoring standards and methodology guidelines, to ensure any data collected during ground vibration monitoring is accurate.
Although now applied to construction work, vibration monitoring standards have originated in relation to mining. Vibrations from blast-produced vibrations were monitored by the Bureau of Mines and studied to establish what potential damage or annoyance they might cause. The Bureau of Mines collected ground vibration data and created standards for what they believed to be safe levels of ground vibrations.
The National Cooperative Highway Research Program, or NCHRP, identified that blast-produced vibrations created on roadway construction projects adjacent or close to historic buildings needed to be monitored. The NCHRP compiled a selection of their current successful practices that related to the impact of vibrations on landmark buildings. In a hope to educate the public and construction companies about how to preserve historical buildings, the NCHRP report summarizes US literature reviews about historic structures and highlights case studies relating to the impact construction vibrations have on historical buildings.
As California is a large state with multiple terrains, state-wide regulations relating to vibration monitoring specifications vary and can be inconsistent. If an individual or company wishes to dispute the rules from a specific area of California, hard data is required to initiate new standards for vibration monitoring.
To create this hard data and to ensure you meet the current ground monitoring standards in California, ground vibration monitoring must be as accurate as possible. Here are some essential things to consider about ground vibration monitoring:
The sensor needs to be placed directly on the ground or on the side of the structure that will face the blast. Try to set the sensor on a flat surface and avoid laying the device on concrete or sidewalks as this can cause inconsistencies in the results. Similarly, do not place the device on loose soil or gravel as this surface does not accurately reflect the vibrations the structure receives.
If you need to bury the sensor, place the sensor in a hole at least three times its height and pack soil around the sensor. A sensor can also be bolted or clamped to bedrock if burying it is not possible.
Contact G3SoilWorks today to maximize the productivity and profitability of your projects in Southern California. Navigating state laws and requirements for ground vibration monitoring can be difficult, and our expert team can support you through your project with our geotechnical and geological experience.
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