2020年12月，亚特兰大耗资3.213亿美元的供水项目的最终调试不仅仅意味着完成五年的努力来增强该市紧张的供水资源。在迫在眉睫的干旱的迫在眉睫的幽灵中开始，并在全球大流行期间结束了这项多方面的项目，克服了多重技术挑战，以赢得与实时的实力对手的比赛，从而使亚特兰大的下一世纪饮酒饮料供应。

除了将一次性采石场转变为24亿加仑的原水存储设施外，该项目团队（由PC Construction和H.J. Russell＆Co。的建筑经理At风险合资企业领导），驶入了12.5英里的5英里。FT-DIA隧道穿过硬片状片岩基岩以下400英尺以上。盲孔钻孔创建了11英尺深的235英尺深的深度硬岩石隧道通道轴，直径在8英尺至40英尺之间。新的2亿和13500万加仑的泵站管理从查塔胡奇河到采石场的两向水流，以使治疗系统保持平衡。

亚特兰大高级流域董事阿德·阿伯恩（Ade Abon）说，缺水的后果超过了与如此雄心勃勃的项目范围和日程安排相关的许多不确定性。他补充说，这使CMAR成为挑战的最佳交付工具。

“The city couldn’t solve the technical problems by itself, and we couldn’t afford a long, drawn-out design and construction process,” Abon says. “CMAR gave us the expertise we needed.”

PC Construction project director Bob Huie adds that the project team readily embraced the city’s mantra that “time is king” while also providing the collaborative environment necessary to find optimal solutions to sometimes knotty problems.

“On a project like this, people get to see what other major stakeholders do,” Huie says of the approach’s benefit. “Because they know more about it and understand the nuances of it, they can coordinate their work and participate in the process at a higher level. That creates better efficiency and higher quality.”

The project required the installation of three 1,800- hp, 40-milliongallon- per-day submersible pumps fabricated by German manufacturer Andritz for the quarry pump station.
布莱恩·格拉斯（Brian Grassel）的照片

吃吧

CMAR’s benefits were apparent when the PC/Russell joint venture joined lead engineers Stantec and River to Tap Inc. at the 30-percent design stage. With tunnel mining forming the backbone of both the water system and construction’s critical path, the original plan called for the project to be built in two phases.
当对设计团队的概念进行广泛的构建前评估，以这种方法发现了潜在的预算和时间表问题时，该市将这项工作巩固为单一合同。PC Construction表示，这使团队能够重新设计，重新协调和重新确定工作，最终从计划中减少了数百万美元。

When construction kicked off in December 2015, the project team still had a full plate of tunneling-related challenges to solve, some of which were as old as time itself. Adam Bedell, Stantec’s senior lead geologist and assistant resident engineer for the project, explains that the sharply varying characteristics of Atlanta’s Piedmont saprolitic soils and bedrock made accurate borings a must, particularly for such a long, complex route.

“We also had to consider the effect of a pressurized tunnel on groundwater conditions and its proximity to other existing underground infrastructure,” Bedell adds.

该设施的泵站位于2.4亿加仑的原水存储设施附近，获得了LEED银认证。
布莱恩·格拉斯（Brian Grassel）的照片

Then there was the matter of using a relatively inexperienced workforce to handle what would be a nearly continuous 48-month tunneling effort spread across four sites and combining drill-and-blast techniques with a 400-ft-long, 12.5-ft-dia tunnel-boring machine, nicknamed “Tunnel Mike.”

Jacob Coibion, project manager for tunneling subcontractor Guy F. Atkinson Construction, which teamed with Technique Concrete Construction for the project, explains that many Atlanta-area trade workers with underground experience had left the area following the conclusion of the city’s last major infrastructure construction effort several years earlier.

Coibion​​说：“该项目的步伐意味着要提高生产力，但我们也必须使其安全。”他补充说，在新员工培训的四天内，近距离的现场监督对于维持对安全的重点至关重要，并通过定期随访会增加。
他说：“因为工作是如此分散，我们很容易失去重点。”

当Mike遇到源自附近工业区的受污染的地下水区域时，出现了意外的安全尺寸。放慢速度以保护狭窄的空间，直到危险到过去，隧道钻孔机能够安全地采取速度并完成其五英里的旅程，并使用GPS指导和激光定位到达3英寸以内预选突破点。

采石场泵站装载区和垂直涡轮泵的景观。
布莱恩·格拉斯（Brian Grassel）的照片

远程教育

另一种安全改编正等待着2020年亚特兰大供水计划，因为Covid-19的传播使该项目的最后几个月变得复杂。项目团队在各种元素完成后实施了掩盖，社交距离和其他措施，但是对于预定的春季组装和安装三个1800 hp，300英尺长的40 mgd潜水泵将需要另一种方法德国制造商安德里兹（Andritz）为采石场泵站。

Huie解释说，泵供应合同需要安德里兹（Andritz）代表的指导，安德里兹（Andritz）代表由于大流行旅行限制而无法前往美国。在泵工程的三个月后，边界仍然被封锁，并且该项目的终点线诱人，PC/Russell团队寻求可接受的监督替代方案。

利用大流行的远程通信选项的扩散，项目团队在泵安装站点安装了高清摄像头网络。Andritz专家使用视频会议平台进行了远程和实时监视工作的每个步骤。到八月，泵已经到位并准备就绪。

该项目的隧道钻孔团队在2018年秋季结束。
照片由Ulrich Brinkmann摄影

“Knowing they’d have no direct supervision, our team had made the most of the delay, preparing for the process and communicating with their counterparts in Germany to understand exactly how the pumps worked,” Huie says. “As it turned out, the people at Andritz said it was one of the better installation and commissioning jobs they had.”

The same could be said for the overall project. According to the PC/Russell joint venture, the work was completed for $5 million below the $321.3 million guaranteed maximum price, and there were no recordable incidents or lost-time accidents among the team’s 209,000 hours on the job.

Huie将该项目描述为“非常激烈，艰难和具有挑战性的工作的五年”，将CMAR促成的合作归功于取得成功和创新，在其他情况和交付方法中，这可能更难以实现。

“日常项目的合作成功ful,” he says. “When we encountered problems, we all got together around the table and analyzed issues. Everyone shared the risk, understood the problems and participated in solving them. It goes to show that when people come together with a common goal and work in the best interests of the project, you can get some tremendous results,” he says.

Abon同意，注意到创造每个参与者都有声音并可以做出贡献的环境的重要性。他说：“没有CMAR，我不知道您将如何做这一切。”