The Highway 10/Connect Detroit Lakes Project is a joint effort between the Minnesota Department of Transportation (Mn/DOT), the city of Detroit Lakes and the Burlington Northern Santa Fe (BNSF) railroad. The goal of the $37 million construction project is to improve safety and mobility along the route.
The project was divided into four phases, which included reconstruction and realignment of approximately three miles of Highway 10, realignment of the BNSF railroad, reconstruction of 1/2 mile of Highway 59 between Highways 10 and 34 and the construction of a frontage road around Big Detroit Lake from East Shore Drive to Detroit Lakes’ downtown area.
Part of this project calls for a roadway underpass to replace a busy roadway/railway crossing. Construction of the underpass requires lowering the ground water in the affected area. As a result, the dewatering process requires monitoring the area for settlement, and the railway also is monitored to prevent any derailments.
Prior to installing the monitoring system, Mn/DOT surveyed the area to establish control and set coordinates and elevations for the prisms. The monitoring system was placed on one control and backsighted onto another.
To aid in this monitoring, a geodetic monitoring system was set up to measure the northing, easting and elevation for a series of points arrayed around the project area. This geodetic monitoring system consisted of a Leica GeoMoS geodetic monitoring system and Leica TCRP1201 total station , along with 56 prisms and a radio communication link. An additional 12 prisms were added for extra coverage while pile-driving operations took place during a two-week period.
The system was intended to be portable for movement to other areas of the project as needed. This included mounting the yagi antennas for the radios on portable stands for easy relocation.
The total station was installed on the rooftop of a nearby supermarket that overlooked the project area. This location affords good line of sight for the radio link connection back to the project trailer, where the computer running the GeoMoS server is located. The prisms were already installed at the desired points and coordinates were provided for their locations. These locations were imported into the GeoMoS software and an instrument set-up and orientation was established. Prisms were grouped within the software according to tolerances, and measurement cycles were set up to establish the data-collection rates.
Once this initial set-up was complete, the system started the automated monitoring of the prism points. Measurement data is captured on an ongoing basis and stored in an SQL database. An e-mail alert was created to send directly to the project manager if tolerance levels are exceeded. Analysis is made in real-time to determine settlement values and posted to the web for collaboration.
The joint project, when complete, will improve safety at railroad crossings and intersections and provide mobility for Highway 10 through-traffic without obstructing access for local motorists. The city will benefit from fewer at-grade railroad crossings, improved traffic flow, reduced congestion on highways and safer and alternate routes into downtown. The addition of project treatment ponds for roadway runoff will help improve water quality flowing into the Pelican River and Detroit Lakes.