This is an awesome limited access foundation project from Crux Subsurface! They designed and installed micropile foundations for new steel tubular towers to replace old steel latice structures. The high altitude (about 10,000 feet) meant limited construction season window, and challenges with the size of helicopter needed for loads. They also provided an innovative steel cap design to the micropiles, thereby avoiding the need to bring in additional concrete and rebar for a traditional micropile cap. Check out the excellent video below. [Source: Read more about the project at Crux Subsurface. Image: Crux]
Golder was the geotechnical designer for two of the most challenging segments of the Stockholm City Line in Sweden. Their work included foundation improvements for a tunnel beneath a historic portion of Stockholm, 3D modeling of rock mass deformations, and development of a specialty software for City officials to monitor the large data sets being gathered for the project, including settlements, ground water levels, vibrations, and more. [Source: Read more about this interesting project from Golder Associates. Image: Nicklas Wijkmark]
Police were called out to one geotechnical investigation site in metro Sydney, Australia last week after residents unhappy with the proposed WestConnex project entered the work site. The crew abandoned drilling tools and equipment on the site, an apartment complex. WestConnex geotechnical contractors canceled another planned investigation as well based on the public reaction. Residents of the apartments were notified in advance of the work, and WestConnex indicated that the proper permission for drilling had been obtained from property owners and/or apartment complex management. But there is clearly a very vocal group of opponents to the project that would link the congested M4 motorway to Sydney Airport and Botany Bay. [Source: Read more about the protests in the Daily Telegraph. Image: Daily Telegraph]
Dewind One Pass was involved in constructing a cut-off wall to address seepage issues at Tyler Dam in Tyler, Texas. The earthen dam was constructed of clay, but the foundation soil consisted of a very permeable silty sand material. The remediation involved a mixed-in-place soil, cement, and bentonite cutoff wall on the downstream face of the dam, about halfway between the crest and the toe. Dewind won the job, and the City's consulting geotechnical engineer narrates this video explaining everything about the project and gives them very glowing reviews. It is well worth your time to watch! [Source: Dewind YouTube Channel. Image: YouTube]
Moretrench was contacted by NYCDEP after turbid water was noticed seeping from the toe of their Cannonsville Reservoir Dam, in the Catskill Mountains. The problem was determined to be related to an exploratory borehole conducted for a hydroelectric plant project that intercepted an artesian aquifer in the underlying glacial till. Moretrench first installed a series of wells to dewater the artesian unit using the Sonic drilling method. Once the artesian aquifer was depressurized, the owner was able to stop their reservoir draw down and Moretrench was able to grout the borehole to seal off the aquifer. As a geotechnical engineer, my take-away from this project is the dangers of creating very serious problems when drilling exploratory holes around an active dam if your boreholes are not properly abandoned. [Source: Read More about the project at Moretrench. Image: Moretrench]
The repaired cutterhead has been in the pit several weeks now, and the final three pieces of shielding for the Bertha TBM have been lowered into the access pit. Seattle Tunnel Partners team members will complete the reassembly of the machine, and manufacturer Hitachi Zosen will conduct a series of tests to make sure the TBM is fit to resume tunneling. The most recent STP schedule indicates they expect to resume tunnel boring in the later part of November. [Source: Alaskan Way Viaduct WSDOT. Image: WSDOT]
The troubled Alaska Way Viaduct Replacement Tunnel TBM known as Bertha has reached a milestone in its repair. The front cutterhead has been repaired, and has been lowered back into the access shaft to be re-attached to the TBM. The time-lapse video below shows the cutterhead being lowered down into the access shaft. What caught my eye was the number of steel cables on the crane blocks...that's a heavy lift!
After the 2011 Fukushima earthquake, the reactors at TEPCO's nuclear facility began leaking radioactive groundwater. The plan to contain the contamination is to use ground freezing to construct an "ice wall" to cutoff the flow. Acton, Massachusetts based Geocomp has been contracted by TEPCO to provide engineering services for the ground freezing. Geocomp has subcontracted specialty geotechnical contractor and GeoPrac sponsor Moretrench to provide their specialty ground freezing expertise as well. Moretrench is a world leader in the design and construction of ground freezing projects. The Geocomp newsletter (from a few months ago) noted that the report deliverables will need to be provided in English and Japanese.
Hatch Mott MacDonald received the prestigious ACEC Grand Award at the 2015 Engineering Excellence Awards Gala on April 21. ACEC had this project description in their program:
More than six miles long and 43 feet in diameter, the new Niagara Tunnel is the largest renewable energy project in the world. Providing much-needed power for the city of Niagara Falls, it is located deep beneath the city and is more than one and a half times wider than the English Channel Tunnel.
The Bertha TBM just received a shipment of spare parts to repair the giant tunneling machine. The manufacturer decided to redesign the seal system to make it easier to access from the inside, if necessary. That's probably a good idea considering the prospect of a repair like this one once the machine is moving beneath downtown Seattle. Other improvements and repairs to the TBM include:
A new main bearing
Enhanced monitoring systems
Added steel to strengthen the machine and accommodate the new seal system
Widened openings at the center of the cutterhead
Extended arms to mix excavated soil in the chamber behind the cutterhead
Fugro has completed one of the largest offshore geotechnical investigations in history according to Hydro-International.com. The investigation was performed by two vessels, MV Greatship Manisha and MV Bucentaur (pictured here), for DONG Energy's 1.2 gigawatt Hornsea Project One project which is located 120 km off the UK's Yorkshire coast. The investigation (contract valued at GBP13 million) consisted of 2,800 metres of seabed cone penetration testing and more than 5,000 metres of boreholes over a four month period. [Source: Hydro International. Image: Hydro International]