Recent Development in the Design of Hard Rock Tunnel Boring

Snyder, L., Loval, R., Williams, R. Recent Development in the Design of Hard Rock Tunnel Boring Machines for the Mining Industry.
1992 Tunnelling Association of Canada Annual Publication.
Recent Development in the Design of Hard Rock Tunnel Boring Machines for the Mining
Industry
L. Snyder
Snyder Engineering
Arvada, Colorado
R. Loval
International Tunnel Equipment Ltd.
R. Williams
International Tunnel Equipment Ltd.
Toronto, Ontario Denver, Colorado
Abstract:
Underground mining development requires tunnels to be excavated in a variety of rock conditions
and configurations. Recent innovations in Tunnel Boring Machine (TBM) design have allowed
for an evolved style of TBM which has distinct advantages over the standard machines. Present
day conventional hard rock TBM's were developed primarily for the long, relatively straight
tunnels of the civil construction industry, thereby making them for the most part, unsuitable for
the sharp curves, turnouts, declines, inclines and ramps required in many mining environments.
The 5 to 36 foot (1.52 to 11 m) diameter machines are capable of boring tunnels with curve
radiuses as small as 40 to 90 feet (12.2 to 27.5 m) depending on size.
These short turning radiuses can be accomplished while gripping the tunnel walls horizontally in
the traditional manner or vertically as required when intersection existing tunnels, or making
turnouts from the tunnel that the machine has just bored. The machine's length is approximately
half of a traditional machine's length while still employing a full measure of thrust, horsepower
and rock cutting ability. The machine's short length, combined with a patented machine structure
allows it to steer while boring without causing harmful eccentric loads on the cutterhead and main
bearing assembly.
The machine configuration is versatile and can be easily modified to operate in a wide variety of
conditions.
With the addition of an anti-slip device the machine can bore inclines up to 45 degrees.
By adding spacers the distance between the grippers can be accommodate stepping through steel
ribs or to gain more room for activities, increased to roof bolting
The rear gripper can be oriented to any angle from horizontal to vertical to accommodate turnouts
or to avoid clamping on weak seams of rock.
With the rear grippers removed a full tunnelling shield with thrust jacks can be attached to the
front grippers. Steel ribs and lagging or precast concrete segments can then be built in the tail of
the shield. Operating in this mode the machine thrusts off the tunnel lining as a normal shield.
This Compilation of TAC Papers was prepared courtesy of
Snyder, L., Loval, R., Williams, R. Recent Development in the Design of Hard Rock Tunnel Boring Machines for the Mining Industry.
1992 Tunnelling Association of Canada Annual Publication.
Abrege:
L'exploitation mlmere sous-terraine exige l'excavation de tunnels dans toute une variete de
conditions et de configurations de roches. Des innovations recentes, dans le domaine de la
conception de Machines a Forer des Tunnels (MFT) , ont permis l'introduction d'un style avance
de MFT aux avantages marques par rapport aux machines traditionnelles. Les MFT
conventionnelles actuelles, pour roches dures, ont ete concues principalement pour forer les longs
tunnels relativement droits de l'industrie de la construction civile, ce qui les rend de fait
inappropriees pour le forage de virages a forte courbure, d'evitements, de declivites, de pentes et
de rampes necessaires dans de nombreux environnements miniers. Les machines de 1.52 a 11
metres de diametre sont capables de forer des tunnels avec des virages aux rayons d'une etroitesse
allant de 27.5 metres, selon la taille.
Ces virages it rayon extremement court doivent etre creuses en serrant de tres pres, a
l'horizontale, les parois du tunnel, de la maniere traditionnelle, ou a la verticale, le cas echeant,
lors du croisement avec des tunnels existants ou lors du forage d'evitements depuis le tunnel que
la machine vient juste de forer. La longueur de la machine est d'environ la moitie de celle de la
machine traditionnelle, tout en utilisant toujours un regime maximal de poussee, de puissance et
de deroctage. La courte taille de la machine, alliee a sa structure brevetee permet son guidage lors
du forage sans pour autant occasionner de charges excentriques dommageables, pesant sur la
tetefraise et l'assemblage du support principal.
La configuration de la machine est tres polyvalente et peut fadlement etre modifiee pour
fonctionner dans une grande variete de conditions.
Munie d'un dispositif supplementaire anti-derappant la machine peut forer des pentes pouvant
atteindre jusqu'a 45 degres.
L'ajout de pieces d'ecartement entre les pinces permet d'avancer a travers les nervures d'ader ou
de gagner davantage d'espace pour les activites d'ancrage de boulons.
La pince arriere est orientable dans tous les angles, de l'horizontale a la vertic ale, pour s'adapter
aux evitements ou pour eviter la fixation sur des veines de roches friables.
Les pinces arrieres etant retirees, un bouclier avec verins de poussee pour tracage en veines, peut
etre fixe aux pinces avant. On peut alors monter, a l'arrihe du bouclier, des nervures de
renforcement en acier et des segments de gamissage ou des voussoirs precontraints en beton.
Fonctionnant dans cette maniere, la machine se propulse le long des parois de tunnel comme un
bouclier normal.
Keywords: General Machine Arrangement; Steering Method and Turn Radius Capability;
Stability, Rigidity, and Boring Efficiency; Versatility and Adaptability; Prototype; TBM with
Anti-Slip Gantry; Gripper Leg Spacing; Excavating Turnouts.
This Compilation of TAC Papers was prepared courtesy of