Mosul Dam Project – Maintenance grouting and rehabilitation of the bottom outlet tunnels

Following the recent events, that were the occupation and the control of the ISIS terrorist organization of the Mosul Dam that led to a lack of maintenance for 3 weeks, the Iraqi Government had to face a severe issue and had to respond to the concern of the safety of the dam to avoid its deterioration, due to the significant reductions in the interventions planned Out of this way, the Iraqi government invited various global international companies, to participate to the sustainment of the Dam, including TREVI GROUP that is a worldwide leader in maintenance and rehabilitation of the dams. The Group is also very active in the introduction of new technologies. Certainly, the action taken affected positively the typology and the quality of reinforcement of the Mosul Dam, especially when the government decided to use the expertise of the US Army Corps of Engineers as a consultant to oversee the maintenance and the evolution of the contractual work. After intensified repairs, Iraqi officials claim the massive Mosul Dam has been saved from impending disaster. During the flooding season, the water level flow was raised to 321 m, a level that is higher than the estimated safety level of the last ten years, that was 319 m. This certainly could unleash quantity of water that will satisfy the needs of the region and the area. Definitely a constant, continuous maintenance with grouting method will strengthen and increase the solidity of the area underneath the Dam’s foundation, reduce the leakage and maintain the Mosul Dam safety that, at the same time, will affect positively the whole needs of the population living around this area. The Iraqi Water Resources Ministry awarded the Mosul Dam Project to Trevi in March 2016, while the Works Supervision was entrusted to the US Army Corps of Engineers acting as Iraqi Customer Consultant. Mosul dam was in very serious dam safety conditions and was judged to be a very high risk, predominantly because of the problematic foundation conditions which consist of Gypsum beds and highly fractured rock units. It’s a significant structure in Iraq, it’s really the most important reservoir for hydropower, irrigation water and drinking water for major cities along the Tigris. The contract mainly involves the stabilization of the dam foundation, consisting of rocks that dissolve in contact with water, thus creating dangerous fractures and cavities for the stability of the structure. This special and urgent intervention is carried out from the dam crest, but above all from the injection tunnel, which runs longitudinally along the axis of the dam itself. As instructed by the American Works Supervision, drilling and grouting works are carried out up to a depth of 200 meters. Here, on the surface, and for the first time, the core of the dam is also drilled which is made of clay. For this purpose we use the dry technology, that is, a continuous auger with coatings, for a depth of about 40 meters, until reaching the rock. Once we touch the rock, we lay a PVC “grouted” pipe; then, at a later point, we resume the rock drilling, using – in this case – a lubricating liquid, like water. In particular, 3 main grout mixing units were assembled and we placed 20 highly automated units in the intervention areas, for dosing and grouting the grout. A fully computerized system called “T-Grout” has been developed for the management, control and acquisition of data in order to have a database for similar future operations. Another work entrusted to Trevi is the rehabilitation of both tunnels and their floodgates, which constitute the bottom drainage of the dam. Trevi is currently working with 660 skilled Italian technicians, in addition to Turkish, Philippine and Indian workers and local labourers. The company works in a difficult environment, being about 20 kilometers from the well-known war conflict. To this end, it is important to highlight the essential presence of the Italian Army, which – with its 500 soldiers – guarantees the necessary security. There’s a significant interaction, conversations, technical discussions ongoing every minute of every day. One of the goals of the US government is to train the Ministry of Water Resources and their staff on the new procedures utilized and the new equipment and computerized monitoring system developed by Trevi. Been my pleasure to be part of this project, it has certainly been a great partnership between Army Corps and Trevi and working in this difficult environment and being very successful. Due to non consideration of the project by the international experts from 1990 to 2016 and the degeneration of the grouting rigs and the various mixing plants, the need became exigent to rehabilitate the grouting curtain and the bottom outlets, in addition to a consultancy, to evaluate the Dam safety. Correspondingly, the Ministry of Water Resources along with International Company Trevi, agreed on the rehabilitation of the grouting curtain and the bottom outlet of the Dam. Now we are three parties working in the Mosul dam, to make it safer. Trevi with good experience, with high technology, with equipment, is working here in Mosul dam and making it safer. The corps of engineers are also working together to give support to the Mosul dam. So we are three parties: the American corps, Trevi, and the Iraqi staff who also have a long experience in the Mosul dam. Despite the environmental difficulties and the high technical requirements imposed by the American Works Supervision, we are confident that Trevi will successfully complete also this challenge at the Mosul Dam in Iraq.

2 thoughts on “Mosul Dam Project – Maintenance grouting and rehabilitation of the bottom outlet tunnels

  1. Only if u could have subtitled it, it would have been beneficial!!

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