TUNNEL BORING MACHINE (TBM) METHOD There are two major shield methods around: earth pressure balanced (EPB) and slurry type shield machine. Selection of shield method depends on ground conditions surface conditions dimensions of the tunnel section boring distance tunnel alignment and construction period. Both are closed!face type shield machines meaning the "head" part of machine is "closed" and separated from the rear part of machine. The "head" has a wor#ing chamber filled with soil or slurry between the cutting face and bul#head to stabili$e the cutting face under soil pressure. The EPB type shield machine turns the e%ca&ated soil into mud pressure and holds it under soil pressure to stabili$e the cutting face. 't has e%ca&ation system to cut the soil mi%ing system to mi% the e%ca&ated soil into mud pressure soil discha discharg rge e system system to discha discharg rge e the soil soil and and contr control ol system system to #eep #eep the soil soil pressu pressure re unifo uniform rm.. Therefore EPB may not be applicable for the roc#y soil that is difficult to turn the e%ca&ated soil into slurry. 't can be used at ground predominated by clayey soil. The slurry type shield machine on the other hand uses the e%ternal pressuri$ed slurry to stabili$e the cutting face similar to bored piles or diaphragm walls using bentonite to contain the trench wall. The slurry is circulated to transport the e%ca&ated soil by fluid con&eyance. con&eyance. Besides ha&ing e%ca&ation system the slurry type shield machine has slurry feed and discharge euipment to circulate and pressuri$e slurry and slurry processing euipment on the ground to adjust the slurry properties.
GENERAL KNOWLEDGE ABOUT TBM TUNNELS
typical typical rail tunnel tunnel section with its components components
Schematic construction seuence for TB*
shield shield machine machine at factory ready ready to transport transport out to the the site
*ain components of a shield machine
EARTH PRESSURE BALANCED MACHINE (EPBM)
Schematic representation of EPB*
Schematic representation of EPB*
Types of cutting face of EPB*
EPB* circulation system
Typical site utili$ation plan for EPB* including wor#ing shaft gantry crane segment stoc# yard tan#s etc.
Section &iew of the EPB* site utili$ation
SLURRY TYPE TBM
Schematic representation of a slurry type shield machine
+utting head s#etch of slurry type shield
Types of cutting face of slurry type shield
Slurry type TB*: Slurry circulation system
Slurry type TB*: Slurry circulation system
Slurry type TB*: Slurry circulation system
Slurry treatment plant
Typical site utili$ation plan for slurry type TB* including wor#ing shaft gantry crane segment stoc# yard tan#s etc.
Section &iew of the site utili$ation for the slurry type TB*
SHAFT CONSTRUCTION
Shaft construction using diaphragm wall method (+,-)
Shaft construction using diaphragm wall method (+,-)
Shaft construction using diaphragm wall method (+,-/). ccess stairs &entilation and passenger hoist are pro&ided.
LAUNCHING AND OPERATION
*ain body of the shield machine being lowered down into launching shaft. 0rom there the TB* system is to be assembled and starts boring.
1owering down the main body of shield machine into launching shaft
recei&ing shaft to accommodate dismentle (right) and assemble (left) TB* at the same time (+,-/)
ssemble TB* (+,-/)
The shield machine at wor#
The function part of TB* (bac#up) at the rear (+,-/) Work Sequece 1ower main body cutting head segment erector screw con&eyer tail shield thrust frame 2 ssemble TB* 2 Erection of reaction frame 2 +onnection of hose and cables 2 'nstallation of 3 to nos. of temp segments 2 'nitial dri&e 2 +ompletion of initial dri&e 2 *odification of TB* including remo&al of reaction frame cradle and temp rings laying rail 2 *ain dri&e 2 Brea# through soft eye (reach recei&ing shaft) 2 4ismantle TB* No!e" ! 5antry crane (for e%ample 6ton 3ton) is normally used crossing the shaft. ! 1ower down TB* components to the shaft needs hea&y lifting. 7--ton or 8--ton crawler crane is needed. ! TB* production rate depends on soil condition. 9ormally at !m;d. ! 5round impro&ement is necessary at recei&ing shaft end for TB* to pass through (about 6!3m in length). Start end depends on ground conditions. ! 5routing to the gap between shield s#in and segment following segment installation from ground surface. ! 4ismantle TB* can be done in launch shaft after being transporting bac# from recei&ing shaft end to the launching shaft end lea&ing behind shield s#in at recei&ing shaft end.
LINING
The start end of tunnel lining (+,-/)
1ining segments are being lowered down from shaft to the locomoti&e
+lose &iew of segment lining. typical ring of lining: .3m width with 7 segemnts to be joined by bolts. 9ote that the joint of neighbouring rings to be staggered (+,-/)
1ocomoti&e rail (+,-/)
The locomoti&e. 't transports muc# out and segments to and fro from shaft to the TB* (+,-/)
+ompleted tunnel with linings. 0rom here st stage concrete rail trac# &entilation electrical and other cables etc. starts installation.
PIPE #ACKING
Pipe
TBM $IDEO
TB* brea#s through soft eye
TBM TERMINOLOGIES B%ck&' Grou!'* (!%'"k' *rou!): 5routing to fill &oid between the lining and the ground (tail &oid) by grout injection C+ce T',e: Segment erection 2 e%ca&ation ; bac#fill grouting 2 segment erection EPB: Earth Pressure Balance (Shield *achine) Go'%!Cr%e: 5antry crane Se*,e! =ing and 1ining: Se*,e!: a splice of precast concrete to form part of ring structure. This ring is also called primary lining. The inside surface is sprayed with concrete usually for waterproofing and finishing. lso called secondary lining. Segment 2 1ining (primary secondary) or ring S-%& t: ! To allow muc# ta#en out lining material brought in TB* lowering in and assembly reaction force at the start operation space ! 1aunching shaft intermediate shaft recei&ing shaft turning shaft Scre. Co/e+or : +arry e%ca&ated roc#s and earth from cutting face to the rear of the completed tunnel
Muck: Soil slurry O/er0ur1e: 4istance from top point of tunnel to the surface of ground. >sually ! .4 TBM: Tunnel Boring *achine MAIN REFERENCES .
NEW AUSTRIAN TUNNELING METHOD (NATM)
The 9ew ustrian Tunneling *ethod (9T*) an alternati&e and cheaper way for tunneling.
9T* support tubes installation (double layer)
9T* support tubes installation (single layer)
9T* support system s#etch
MAIN Basler@?ofmannAs catalogue
REFERENCES
