This video highlights the risks of tunnelling in poor ground conditions, highliting the critical need for thorough ground investigations before construction and continuous probing ahead of the tunnel during excavation. The construction method should be carefully chosen based on geological conditions and risks, with proactive ground stabilisation measures implemented where necessary. Tunnelling is essential for development, but its associated risks must be thoroughly understood, and mitigation measures should be developed before the construction stage. Follow us Tunnel Engineering for more insights. #tunnelcollapse #geotechnicalengineering #tunnelling #civilengineering #tunnelengineering
Eric Bennett
1mo
This occurred at Lake Mead Intake #3 drive as we were driving our starter tunnel. Some may be familiar with it. We attempted consolidation grouting ahead of advance but were unable to stop inflows due to our depth under the aquifer above us and a huge mud seam as we were crossing a section of faulted zone. Our entire TBM chamber was inundated and the crew hastily evacuated when the whole thing gave way. Lots of equipment and progress lost, and Months of drilling from surface into the void to place concrete in, then chamber re excavation and recovery. Attempts to reopen the starter tunnel eventually were abandoned, and a bulkhead was built, in favor of realignment to avoid the faulted zone, which was the solution.
Earnest De Vries
2mo
Seen this once before. A mine tried to spile their way through a very sandy patch by applying gunnited arch containment installed against the spiling steel and so temporarily keep the operations area safe and open. Then they mined to a point where the sand they were cutting through was intersected by a area of water containment which washed in the sand to open an excavation stretching beyond the spile ends. When doing excavating through known sandy areas, it should be priority number one to drill piloting to provide cover to a pre-determined depth ahead as the go to safety task to do. As well as daily extending the pilot drilling in opposing directions.
Immediately stop the work under these conditions and resolve the issues before resuming tunnel construction. 1. Conduct a thorough geotechnical investigation to ensure all parameters are understood. 2. Implement proper tunnel monitoring systems to detect and address any potential issues promptly. 3. Verify and assess the ground conditions to ensure they align with the design assumptions. 4. If the water table is very high, establish an effective dewatering system before proceeding. 5. In cases of poor soil conditions, execute proper forepoling or pipe roofing techniques to stabilize the ground.
This video, apart from the already mentioned, also showed the need to implement a monitoring plan and to obtain reliable information coming from measurement to make decisions
GUILLERMO VALLE
2mo
I was once in a similar situation, there was a water pocket and when they were on site it overflowed; monitoring this type of fault in some areas is complicated, in these cases the solution is just to let it drain; for tunnels in rivers, lakes or sea it is more complicated because you would have to be prepared to provide solutions at the moment; perhaps with cosmic ray instrumentation that has a greater range you can get a better idea of the conditions of the terrain.
Tunnel seismic prediction is a suitable tool for exploring the rock mass conditions ahead of the face. Ask me more if you want to know how it works.
Tunnel. Engineering. Estar consiente y compenetrado sobre los riesgos, que implican, la construcción de Túneles., es importante y necesario tomar medidas de.Seguridad. ( cuando sean suelos saturados, con infiltraciones y aún sean rocosas, pero susceptibles a inundación. Las investigaciones Geológicas ( previas) son esenciales, para “ademar y estabilizar el terreno” Compartí un buen video
Reik Winkel
2mo
Similar like inrush events occur in panel caving mining method.
Dave cook
2moTry probe drilling next time