Dawn Underground Engineering, Inc.

Tunnels and Underground Structures Consultants

About the firm

Dawn Underground Engineering, Inc. is a multi-disciplined engineering consulting practice specializing in the design, construction, and rehabilitation of tunnels and complex underground structures. Utilizing capabilities in civil, geotechnical, and structural engineering, the practice provides specialized design and evaluation services for temporary works, cut-and-cover systems, trenchless construction, and tunnel restoration. Its expertise covers microtunneling, horizontal directional drilling, and both hand-mined and tunnel boring machine methodologies across diverse soil and rock conditions.

Firm type: Civil Engineering · Geotechnical Engineering · Structural Engineering

Capabilities

Geotechnical Engineering

Comprehensive geo-sciences and geotechnical engineering services for owners, utility authorities, municipalities, contractors, architects, and engineers.

Subsurface Investigation Programs
Planning, field exploration, boring supervision, and geological program development to map subsurface conditions.
Geotechnical Data and Baseline Reports
Preparation of geotechnical data reports, construction foundation reports, and geotechnical baseline reports.
Slope Stabilization and Ground Modification
Engineering solutions for slope stabilization, ground modifications, and landslide mitigation.
Retaining Walls and Earth Reinforcement Systems
Design of retaining walls and various earth reinforcement systems to secure excavations and slopes.
Shallow and Deep Foundations Design
Structural and geotechnical design of foundation options, including slabs-on-grade, beams, and piling systems.
Tunnel Route Feasibility Assessments
Initial feasibility studies and route alignment planning for tunnel and deep underground utility corridors.

Underground Engineering

Specialized engineering services for deep underground structures, utility tunnels, shafts, and municipal water/wastewater conduits.

Underground Structure Evaluation and Inspection
Condition evaluation, inspection, and integrity analysis of existing tunnels, pipelines, shafts, caverns, and chambers.
Trenchless Excavation Method Selection
Expert feasibility studies for Horizontal Directional Drilling (HDD), microtunneling, Tunnel Boring Machine (TBM), and Sequential Excavation Method (SEM).
Tunnel and Shaft Stability Analysis
Advanced numerical and empirical stability analysis for horizontal tunnel bores and vertical shafts.
Excavation Support Systems Design
Design of temporary and permanent earth retention systems, including slurry walls, secant pile walls, sheet pile walls, and soldier piles.
Tunnel Linings and Rehabilitation Design
Design of initial support systems and final structural linings utilizing concrete, shotcrete, steel, and segmental lining systems.
Watertight and Waterproofing Systems Design
Engineering of watertight cofferdams, bulkheads, and advanced waterproofing systems for critical underground utilities.
Soil-Structure Interaction Modeling
Computerized analysis of how complex underground structures interact with surrounding soil and rock under static and seismic loading.

Industries

Tunnels · Wastewater · Water Supply · Transit · Infrastructure · Highways & Roads · Stormwater & Flood Control

Projects

City Tunnel No. 3

New York, NY · Tunnels · Client: Grow-Perini-Skanska, AJV

Project details

Provided consulting services during the second construction stage of City Tunnel No. 3, which was designed to bypass two existing historic tunnels. Deliverables included structural design of the tunnel bulkhead to withstand 900 feet of hydrostatic head, engineering of underground electrical and ventilation vaults, evaluation of support systems for down-drilled shafts, and concrete lining strength reports.

Easterly District CSO Phase II Facilities Plan

Cleveland, OH · Wastewater · Client: Northeast Ohio Regional Sewer District

Project details

Assisted with analyses and engineering for preliminary (30%) design of combined sewer overflow (CSO) control infrastructure, including storage tunnels, dewatering, pump stations, and interceptor relief. Key contributions included selecting construction shaft methodologies for cost estimation and evaluating drop structure alternatives.

Northern Boulevard Crossing

New York, NY · Tunnels · Client: MTA

Project details

Performed independent Plaxis soil-structure analyses for Sequential Excavation Method (SEM) tunnel excavation featuring a seven-cell configuration. Reviewed details of the design and geotechnical parameters, and participated in coordination meetings regarding ground freezing operations utilized to control groundwater inflows.

CSO No. 4 and No. 5

Richmond, Virginia · Wastewater · Client: City of Richmond

Project details

Delivered tunneling and underground structure design services for approximately 6,500 linear feet of a 160-inch inside diameter combined sewer overflow retention tunnel. Deliverables included initial feasibility studies, subsurface investigation plans, rock dowel and rib support system designs, and final structural analysis of concrete linings.