3D Microtremor Array Survey

Overview

3D Microtremor Array Survey is a geophysical exploration method that measures microtremor caused by traffic and economic activities, and then estimates the geological structure from the propagation characteristics inside the ground. By arranging many recorders with cable-less / GPS functions developed by the OYO group on the ground surface, we are able to ascertain the geological structure in three dimensions.

Features

Application Example 1. Survey of bearing layer for construction foundation

3D Microtremor Array Survey continuously visualizes the planar depth distribution of the bearing stratum. The figure above shows the S wave velocity structure (Fig. 1) of the bearing stratum in the construction project and the estimated bedrock depth distribution (Fig. 2) created with calibration from a borehole survey. Visualizing the bearing stratum distribution in a planar manner makes it possible to suppress the increase in pile construction costs and delays in the construction period. It also significantly reduces the number of borehole surveys, thereby contributing to increased efficiency for the entire project.

⇒Realize efficient construction by suppressing rework through visualization of the bearing stratum in a planar manner. Facilitating risk communication between order receivers and orderers

Application Example 2. BIM / CIM application in road projects

The figure above shows an application example of this technology in a national highway project. Since the existence of complex buried topography, such as buried valleys, was estimated from the terrain conditions of the site, we conducted a 3D Microtremor Array Survey in addition to borehole surveys. The complex distribution and depth of the alluvium are difficult to grasp with only a limited number of boring surveys. By visualizing these features and using that data to construct a highly reliable BIM / CIM geological model, we contributed to reducing the cost of ground improvement work.

A 3D geological model based on actual measurements can be used to extract geological risks and select optimal geological survey points. Through integration with BIM / CIM, this is an effective tool for facilitating risk communication in the subsequent construction process and for use as an explanatory material for local residents.

⇒Reduce construction risks, suppress increases in ground improvement costs, and support the smooth progress of road projects

Cost comparison with conventional survey methods

Achievements