Plateau Creek Pipeline Tunnels
Location
Grand Junction, Colorado
Client
UTE Water Conservancy District
Services Provided
Feasibility Study
Preliminary to Final Tunnel Design
Cost Estimates
Plans and Specifications
Resident Engineering
Project Overview
The $58 million Plateau Creek pipeline replacement project is part of the UTE Water Conservancy District’s construction program to increase and improve water supply for their more than 70,000 customers. The 14.5 mile water pipeline replacement project included installation of approximately 68,500 feet of 48- and 54-inch diameter steel pipe. To minimize potential environmental impacts on the creek, two sections of pipeline were placed in tunnels (10,200 and 3,400 feet in length), and both were driven by a 10-foot diameter hard rock tunnel boring machine with various classes of support designed for varying rock conditions, ranging from spot rockbolts to stabilized wedges to steel ribs. Pattern rock bolts with mine straps or steel mesh and shotcrete were used. Geology along the alignment consisted of sandstones, shales, and siltstones. The new line gives the capacity to deliver four times the hydraulic capacity of the existing pipe.
Lachel provided a feasibility-level tunnel design and initial cost estimate and the intermediate and final designs for the tunnel portions of the project including plans and specifications and the engineer's estimate for the tunnel. This work included developing the expected ground loads based on empirical and finite element analyses, designing the initial and final ground support system for the various expected ground conditions, developing plans and specifications, and preparing the engineer's estimate related to the tunnel. During the construction phase, Lachel provided a resident engineer and senior tunnel inspector and participated on the Tunnel Review Committee.