It all depends on the size and type of the tunnel desired to have any idea about what is needed; tunnel linings can have cast concrete segements set in place with lifting arms/referred to as segment erectors and the segments are locked in place with a key segment and sealed with rubber gaskets and bolted together at the same time.

Tunnel boring machines used in a pipe jacking configuration dig and push the pipe product in behind the boring machine and the spoil is either pumped out with a bentonite slurry or augered out dry with augers attached to one another as the boring machine advances in the bore.

These units are only limited by job, the job size, pipe size and maximum ramming distance that a pipe can tolerate with and without bentonite slurry and they require transition pits to allow the boring machine to exit the bore enter a dug and piling lined pit where the jacking machinery can be reset to jack the boring machine and pipe again until the job is finished.

Also the typical tunnel boring machine may surpass

fifteen meters in diameter and larger in the case of railway tunnels.

The tunnel muck/cuttings are either pumped removed with a conveyor belt and or a underground train with dump cars are used to move tunnel spoil away from the boring machine to a dump site.

Pnuematic capsule pipelines(with a square configuration of cast concrete sections were used with one square concrete casting tube over the other to remove tunnel spoil in the bottom tube and return with concrete in the bottom tube to be pumped into the tunnel boring machine to be cast in place for an automobile tunnel in Japan.

Depending on the ground conditions encountered or known about the tunnel boring machine is either custom made, or a contractor is found with a tunnel boring machine with the desired configuration for its job. A lot of the current machines are rebuilt and sold for other tunnels and then reused for other jobs or sold for scrap.

Eleven machines were used for the Channel tunnel with muck trains and buried after they were done with them-at least the two main tunnel machines for the main rail tunnels are buried in the tunnel walls at the center of the channel tunnel.

What type? Earth Pressure Balance, micro TBM for pipejacking, open type with tunnel grippers to push agains the tunnel walls to move the borere forward or they can be sheilded against water pressure with a bentonite slurry pumping system for cuttings removal from the tunnel face all the while being pushed forward with hydraulic cylinders pushing against the secured tunnel segments installed with the segment erector allowing easy advance of the cutter head in wet conditions.

A horizontal directional drill unit? HDD

A tracked continous miner or roadheader with a single or dual boom system?

What do you mean exactly- the design stage?, during the fabrication stage in the building plant?, the reassembly time in the launch pit?

What type of cutter heads? for soft rock, disc cutters for hard rock mixed soil/glacial till with boulders, clay?

Are you referring to a dry open cutter head with an auger for spoil removal or a unit with a mud mixer(sheilded) for cuttings removal with bentonite slurry?

Tunnel boring machine cutter heads are sometimes cast in one piece for a specific tunnel or multiple casting/machined pieces are bolted together for ease of assembly and disassembly when the job is done or needs to move to another launching point in a tunneling job.

Please be much more specific as it is fine to know ask about a tunnel boring machine in the design stage, buuuuuut unless you know your actual tunneling conditions from core samples and horizontal drilling for various testing instruments or cameras, it is not a case of one machine fitting all potential tunneling conditions, and pressures from the surrounding rock and potrential water ingress at the tunnel face or roof line. ■

Endri,

Are you trying to design you conveyors around a TBM or offer them for sale to a manufacturer?

There is plenty of information on tunnel boring machinery information on the internet so you can start there by googling tunnel boring machines and you will have much usable information for your use.

Use the links provided above for your use as the links are valid.

lzaharis ■

The outbye spoils conveyor shown on the Herrenknecht website is particularly impressive. It leaves the footwall free for the ingoing inverts and wall segments. Things have some a long way since the Channel TBM which I worked on for Bennet/Markhams.

If the politics had been thrown out of the window I bet the German machines would have done a better job in less time. ■

Hello louis,

I would have sent a PM to you but they have been having new software issues apparently.

I was wondering did you spend all your time around the Robbins machines or the Kawasaki units?; I think it was Kawasaki anyway-been too long:^)? Its a terrible shame in my opinion that they buried the two main bore units at the mid point of the chunnel.

leonz ■