Geotechnical Construction


Northwest Cascade is a full service geotechnical construction contractor, specializing in earth retention, slope stabilization, design build shoring, and underpinning.

Services include:

• Micropiles
• Soil Nail Shoring
• Tiebacks / Ground Anchors
• Specialized Grouting
• Design Build Shoring

Northwest Cascade is in a unique position to offer our geotechnical services in conjunction with our excavation, utility, site development, and road building capabilities. Northwest Cascade’s engineers, project managers, and crews provide innovative, efficient, and cost effective solutions to geotechnical and heavy civil projects. Our experience, expertise, and string teamwork have resulted in successful projects and satisfied customers throughout the Western United States.

We recognize that each project and site brings it’s own unique challenges. We seek to apply the best approach to achieve the most technically and economically feasible results. We have a versatile fleet of equipment that allows us to provide the right tools for each job. Our projects have ranged from hand driven pipe piles at a private residence, to deep foundation elements for bridges and dams.

Northwest Cascade works closely with geotechnical and structural engineers to design and install shoring systems of all types. We strive to build quality projects and long lasting relationships with our customers.


Micropiles are high-capacity, small diameter drilled and grouted piles, used in situations where conventional piles are impractical or cost prohibitive. Micropiles are

Coupled pile 4-26print

Northwest Cascade has extensive experience in designing and installing micropiles, as well as, performing micropile load test programs. Our projects have included pile capacities ranging from 50 kips to 500 kips in areas as diverse as high-rise buildings in congested cities to remote and environmentally sensitive public watersheds. Northwest Cascade has completed micropile contracts ranging from $100,000 to $7,000,000 for clients including the California Department of Transportation, the Washington State Department of Transportation, Kiewit Construction, Sellen Construction, Tutor-Saliba Corporation, Washington State Department of Ferries, Plant Construction, Manson Construction, and many

shaw island 2

others. Micropiles are reinforced with high strength steel components, allowing structural loads to be transferred from unsuitable to competent soils. They are usually installed for bridge and building foundation support, for seismic retrofits, or for slope stabilization/earth retention projects. They are also frequently used in low overhead situations, in areas of restricted access, and in environmentally sensitive areas, where other construction methods are not an option.

Case Studies:

Kangley – Echo Lake Micropiles

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Soil nailing offers a more economical option than traditional shoring methods in many soil types. Soil nails reinforce and strengthen existing ground through the installation of closely spaced steel members (nails) into a slope or excavation. Typically the face of the excavation is then stabilized with the application of shotcrete. Soil nail walls are constructed from the top downward and upon completion, create a zone of reinforced earth which functions as a soil reinforcement system.

In the last five years Northwest Cascade has completed numerous soil nail projects ranging from 1,000 SF to 40,000 SF, and our personnel bring extensive knowledge and hands on experience. We have installed soil nail retaining walls on projects ranging from large public highway expansions to small residential site improvements throughout the Pacific Northwest and California.

Case Studies:

Tacoma Dome Station Soil Nail Shoring

Green River Headworks Shoring

Storman Residence Permanent Shoring

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#2 two drill working


Tiebacks are small diameter drilled elements consisting of steel strands or threadbar members grouted into place and tensioned to provide a preloaded condition to the underlying soil. Tiebacks, also referred to as ground anchors, are used for permanent or temporary shoring support, retaining walls, dam stabilization, and landslide repair. They can provide a cost effective alternative to conventional shoring structures especially in situations where seismic activity is a concern or where excavation is undesirable.

Northwest Cascade has installed tiebacks of all capacities for a wide range of situations from dam stabilizations to deep excavations and to depths of 150 vertical feet. In 2002 Northwest Cascade installed tiebacks for one of the largest soldier pile/tieback walls in the world, at the Carquinez Bridge in Crockett, CA. Our personnel provide the high level of experience and quality of workmanship necessary to produce a reliable, cost effective solution for all types of earth retainage needs.

Case Studies:

Golden Gate Bride Tiedowns

2920 Eastlake Tieback Shoring

Crockett Interchange Tiebacks

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While the use of grout is a common part of all of Northwest Cascade’s geotechnical construction processes, it is also used in various forms on its own for soil remediation and improvement. Northwest Cascade performs a variety of specialized grouting services. The most common are compaction grouting, for improving the density of in situ soils, and permeation grouting, for filling of voids in existing soils, rock stabilization, and ground improvement.


Northwest Cascade has extensive experience in specialized grouting quality control and testing. Our colloidal grout plants provide precise mixing capabilities for a wide range of applications. NWC is often called for emergency situations where conventional methods are not an option and time is of the essence.

Northwest Cascade helped pioneer the use of “Barrel Vault” grouting for tunnel construction in the United States. This technology is common overseas and aids in the installation of underground tunnels in weak soils. Northwest Cascade’s technical experience and “Can-Do” attitude allowed us to enter this market with great success.

Case Studies:

White River Re-Route Grouting

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Northwest Cascade’s engineers and project managers are well versed in all types of geotechnical construction services. We have strong relationships with the geotechnical and structural engineers in our areas of operations. We use these relationships to Create, Design and Build solutions for our client’s needs. We routinely provide both permanent and temporary design-build projects for residential, commercial and heavy civil projects. Please contact a member of our staff for assistance on your particular project.

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Please click on the PDF files below to download case studies.

Golden Gate Bride Tiedowns Orcas Island Ferry Terminal Repair  
Kangley – Echo Lake Micropiles 2920 Eastlake Tieback Shoring  
Highline Community College Tunnel Replacement Tacoma Dome Station Soil Nail Shoring White River Re-Route Grouting
LaGrande Dam Penstock Repair Green River Headworks Shoring Crockett Interchange Tiebacks
Storman Residence Permanent Shoring Shaw Island Ferry Terminal Slip Reconstruction Richmond-San Rafael Bridge Seismic Retrofit