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Gary Brierley - Doctor Mole

Doctor Mole's Underground Experience . . .
Dr. Gary Brierley has been in the underground tunneling industry for almost 50 years. He has been a team member of some of the largest tunneling projects in the country including Boston’s Big Dig, Seattle’s Alaska Way, and Caldecott 4th Bore in Oakland, California.

The following is list of projects that Dr. Brierley has played a major role on:

Saavadra – Moron Water Supply Project, Underground Construction Mangers, Buenos Aires, Argentina
Water Supply Project - Shaft DesignProject consists of 15,000 meters of 3.5 – meter – diameter tunnel being excavated using a Herrenknecht earth-pressure-balance TBM. The Saavedra-Moron tunnel is part of major overhaul of all water supply and waste water removal facilities for the city of Buenos Aires.
Tren Urbano,  Puerto Rico
Dr. Brierley served for more than five years on the Geotechnical Consulting Board for the underground related portions of the Tren Urbano Project in San Juan, Puerto Rico. Dr. Brierley participated in all aspects of planning, design and geotechnical engineering for the Rio Piedras segment, which is currently under construction. Dr. Brierley also helped with design consultation for the proposed Minillas extension. Probably the most interesting aspect of this project is the fact that all work is being procured under a design/build contracting under which is rarely done in the United States for underground construction projects in urban areas.
Brushy Creek Interceptor, Round Rock, TX
Bushy Creek Interceptor - Tunnel DesignBrushy Creek Regional Interceptor consists of approximately 7,000 feet of 110-inch initial diameter machine bored tunnel. The tunnel was constructed in stiff, expansive clay and a competent limestone. A complex fault zone marking the contact between the two formations was crossed. Dr. Brierley provided team executive oversight for the team during design of the tunnel alignment and grade. Work also performed included: geotechnical evaluation, prepared the Geotechnical Baseline Report, assisted in preparing the contract specifications, and prepared the initial tunnel support design, in addition to providing Construction Management services during project construction.
Chattahoochee Tunnel, Jordan, Jones & Goulding, Inc., Cobb County, GA
The Chattahoochee Tunnel is a rock tunnel approximately 49,600 ft. in length with a finished diameter of 16 ft and approximately 825 ft long spur tunnel in rock with a finished diameter of 8 ft. The tunnel will store and convey wastewater. The tunnel will be approximately 120 ft to 350 ft below ground. The project also includes two construction shafts with finished diameters of 30 ft which will be sunk utilizing drill and blasting techniques in rock.
Combined Sewer Overflow Program, Rochester, NY
Clinton CSO ProjectGeneral geotechnical consultant and assistance with design of 22 miles of combined sewer overflow tunnels in Rochester, New York. Project began with a system-wide evaluation of subsurface conditions prior to final location of tunnels. Drilling program including the drilling and logging of 35,000 lineal feet of core in less than six months. Dr. Brierley served as officer-in-charge for the work.
Contract A-146 and A-171, Metro Rail, Los Angeles, CA
Assisted Shank-Ohbayashi with the instrumentation programs for Metro Rail Project tunnel contracts A-146 and A-171. The tunnels are part of a subway system under construction in downtown Los Angeles. The twin, 18.5 ft. finished diameter tunnels for contract A-146 will be driven for 2,000 ft. in soft ground and will pass directly beneath several major downtown buildings. The twin, 18.5 ft. finished diameter by 4,950 ft.-long tunnels for contract A-171 will be driven in siltstone beneath city streets. Instrumentation was used to monitor ground movements in response to tunneling, and to observe the results of construction activities, especially compaction grouting work for contract A-146. Compaction grouting was required by project designers to minimize the potential for building foundation settlement.
Dulles International Airport, HNTB, Alexandria, VA
Perform design services for the fixed facilities of a proposed Automated People Mover System. Design work includes running tunnels and station shells; mechanical and electrical fit-out of the tunnels; a new tunnel for United Airlines’ proposed baggage conveyor system; tunnels for baggage tugs, the East Utility Tunnel and the APM Vehicle Maintenance Facility, as well as full ventilation and fire life safety systems for all the tunnels. The assignment extends from Schematic Design through Detailed Design, resulting in several complete construction packages.
El Salaam Syphon Tunnels, Cairo, Egypt
Served on a value engineering team to evaluate the tunneling options. The project involved four 5.1 m diameter siphon tunnels traversing beneath the Suez Canal which provide water from the Nile River and drainage water to irrigate North Sinai. Primary issues included selection of the tunnel boring machine, third party impacts associated with tunneling under the Suez Canal and layout considerations for the inlet and outlet connections.
Grand and Bates Storm Sewer Relief, St. Louis, MO
Grand and Bates Sewer Tunnel DesignThe Grand and Bates Storm Sewer Relief Tunnel consists of approximately 6,550 linear feet of tunnel to provide storm water drainage relief in the Grand Glaise Sewer District in the City of St. Louis. The project has three access shafts and eight smaller diameter shafts for manholes to allow for discharge of new or existing local storm sewers into the tunnel. The alignment runs beneath a residential neighborhood located in the south of the city and also includes construction of approximately 5,000 feet of storm sewer laterals in the adjacent neighborhoods. The project involved the preparation of construction specifications and drawings for sewers and drainage facilities and wrote the Geotechnical Baseline Report. In addition, the team provided designs for shaft initial support, including jet grouting columns complete with vibrating wire strain gauges to monitor stresses.
Islais Creek Transport, San Francisco, CA
Islais Creek Contract E is a 1,100 ft. long combined sewer and stormwater transport/storage structure that consists of a 250 ft. long 10'-6" diameter tunnel, a 500 ft long 12'-0" diameter tunnel, and 350 ft. of cast-in-place concrete box culvert constructed within soldier pile tremie concrete (SPTC) walls. The tunnels were designed to be driven under compressed air. After award, the contractor submitted a value engineering proposal to use jet grouting as an alternative to compressed air for tunnel construction, which was accepted. The team provided resident engineering, construction management and contract administration services on this project and Dr. Brierley served as officer-in-charge.
L.A. Metro, Red Line Extension, Los Angeles, CA
Dr. Brierley served as a member of the Performance Improvement Team for the Red Line Extension in Los Angeles, CA. The team evaluated many design, construction, cost and scheduling concepts for the work in an effort to reduce cost and streamline production. The team also evaluated waterproofing concepts for the stations and the technical feasibility of building some stations in critical areas by mining methods rather than by cut-and-cover. Many of the suggestions made by the team were incorporated into the program.
Lake Merced Tunnel, San Francisco, CA
Brierley personnel provided construction management and resident engineering services during construction of 8,500 ft. of combined sewer and stormwater overflow tunnel. A large, 18 ft. diameter open-face shield was used to excavate through sandy alluvium, below the water table. The project included a major dewatering effort consisting of over 80 wells along its length, jacking of a sewer pipe feeder, construction of a transition structure, and a 72-in. diameter pipe installed in a hand mined adit. Responsibilities included processing of submittals, change orders, and progress payments; monitoring of construction activities; and monitoring of instrumentation and dewatering programs.
Manapouri Tunnel, Fletcher Dillingham Construction, New Zealand
The Manapouri hydro-electric power station is the largest of its kind in New Zealand. It was designed with a capacity of 700 MW and built by drill and blast. However, on account of a greater than expected surface roughness of the tailrace tunnel it only achieved 580 MW. In order to secure the power supply for New Zealand’s South Island, the plant’s capacity is to be increased to 760 MW and a second tailrace with a length of 9,750 m with a 10m diameter constructed for this purpose. Dr. Brierley provided consultation services on this project.
Minneapolis Tunnel, Minneapolis, MN
The MSP LRT tunnel and Stations Project consists of the construction of 1,280-feet of retained cut, 920-feet of cut-and-cover tunnel, and 7,120-feet of mined and/or bored tunnel(s), all to accommodate a north-and south-bound LRT line. The project also included construction of an underground LRT station to be located near the Lindberg Terminal and an at-grade LRT station to be located near the Hubert H. Humphrey Terminal. Services included the reviewing of design concepts and partially completed construction drawings, and evaluatation of means and methods of construction, the feasibility of tunneling methods, and estimates of construction costs and schedule.
Muni Turnback Project, San Francisco, CA
The Muni Metro Turnback project links five existing Muni Metro lines to surface tracks at the newly completed South Embarcadero Roadway and the Muni Metro extension. The new 18 ft. diameter twin steel tunnels allow for the underground switching and storage of vehicles. The 840 ft. long Muni Metro tunnels cross above existing BART tunnels below Market Street at a separation of 11 ft., where they continue above the BART tunnels to the Spear Street shaft. While advancing the tunnels in December 1994, the wooden hull of a buried mid-19th century ship was encountered. Tunneling started on October 1, 1994 and proceeded with full face breasting and excavation with pneumatic spade on a 24-hour per day, six day operation/one-day maintenance schedule per week. The first shield was assembled in the shaft. After breakthrough, the shield skin was left in place. Services provided included Resident Tunnel Engineering Services to the construction management team for the project. The Resident Tunnel Engineer reported directly to the Construction Manager and was responsible for monitoring the tunneling and instrumentation portions of the work.
NORS Tunnel Project Claims Assistance, Los Angeles, CA
Expert technical assistance and witness before disputes review board for resolution of claims of approximately $3 million arising from construction of a 13 mile long sewer tunnel. Services included a two day presentation to the disputes review board that included the formal presentation of results of analyses, rebuttals to the contractor's presentation and questions and answers to inquiries from the board.
Outfall Tunnel, Kilpatrick & Stockton, Boston, MA
Brierley Associates has been retained to serve as a consultant to the MWRA concerning a major differing site conditions claim for the Boston Outfall protect.
Papago Freeway Drainage Tunnels, Phoenix, AZ
During construction of storm drainage tunnels under Phoenix, Dr. Brierley oversaw the provision of geotechnical engineering, compaction and chemical grouting design, construction administration, and tunnel inspection services for the Arizona Department of Transportation. The project consisted of 27,000 feet of 21 foot finished diameter tunnel and 6,650 feet of 14 ft. finished diameter tunnel driven through loose river run gravels. The purpose of the tunnels is to move water from a depression in the Papago Freeway to the Salt River.
Richmond Transport, San Francisco, CA
Richmond TransportThe project consists of a 10,200 ft. long by 14 ft. diameter sewer tunnel located in the Richmond-Seacliff-Lobos Creek area of San Francisco. The tunnel was driven through 9,000 ft. of hard rock, 1,200 ft. of sand below the water table and a transition zone of mixed face conditions. The hard rock section has been designed for excavation by a shielded tunnel boring machine (TBM). The project also includes excavation of incline and decline tunnels and an underground chamber using drill/blast methods, rehabilitation of a portion of the existing Mile Rock Tunnel and construction of the 24th Avenue Connector Tunnel.
Scajacquada Tunnel Interceptor, Buffalo, NY
Six miles of combined sewer tunnel. Subsurface problems included low rock cover, poisonous gas, high water flows, highly stressed rock, and highly abrasive chert deposits. Consultation services included subsurface investigations and assistance with design, construction and the resolution of contractor claims.
South Austin Regional Wastewater Treatment Plant, Austin, TX
The Lift Station Interconnect Tunnel Project, part of a plan to expand and improve the South Austin Regional Wastewater Treatment Plant, consists of two tunnels and associated access shafts, the first of which is a 1,270 foot long, 60 inch diameter conduit that will allow water to flow between two lift stations, and the second is approximately 526 feet long with a finished diameter of 60 inches. The project involved the preparation of  the GBR and on-site technical support during tunnel construction.
South Interceptor, Montreal, Quebec
The South Interceptor project in Montreal consists of more than 30 miles of tunnels varying in diameter from 8 to 18 ft. For three of the contracts, many areas of bad rock, soil, and mixed face tunneling conditions were encountered. In one mixed-face area the tunnel was constructed with a shield using air pressure. In other areas the tunnels were advanced by drilling and blasting and by tunnel boring machine, with and without pre-grouting. Dr. Brierley served as Consultant to the Montreal Urban Community throughout the entire six yearlong planning, design, and construction period.


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