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INTERNATIONAL SOCIETY FOR SOIL MECHANICS AND GEOTECHNICAL ENGINEERING This paper was downloaded from the Online Library of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). The library is available here: https://www.issmge.org/publications/online-library This is an open-access database that archives thousands of papers published under the Auspices of the ISSMGE and maintained by the Innovation and Development Committee of ISSMGE. Geotechnical Aspects of Underground Construction in Soft Ground, Kusakabe, Fujita & Miyazaki (eds) © 2000 Ba/kema, Rotterdam, ISBN 90 5809 1 066 High-speed railway tunnelling in soft granular Frankfurt ground R.Katzenbach, U.Arslan, G. Festag & A. Rtickert Institute of Geotechnics, Darmstadt University of Technology Germany ABSTRACT: Two examples show the experience with highspeed railway tunnelling in F rankfuit soft ground. At the ”Frankfurter Kreuz” the railway line Cologne-Frankfurt/Main crosses the highways Fra.nkfLu"t-Basel and Colo g;ne Wiirzburg in a tunnel in near vicinity to the Frankfurt/Main airport. The construction of the tunnel was composed of a two step support. ln the first step the crown was excavated under a jet grouted screen. The working face was reinforced with a support core and eight additional horizontal jet grouted columns. ln a second step the lower part of the tunnel was excavated. To verify the soil parameters two series of in-situ large scale shear tests were performed. Within the project ”Frankfurt 21” a new railway tunnel undercrossing the city of Frankfurt/Main is planned. For that various underground tunnels as well as numerous buildings and skyscrapers with their fotmdations, the river Main and the East docks will be undercrossed. ` l INTRODUCTION high speed A ' to FrankfuV railway The new railway line Cologne-Frankfurt/Main is the N , .JA centrepiece ofthe Gennan and the future European high \on%_d\§\““C5 7? Gateway Gardens `={~ B42 speed traffic network and links important national and \(\?,\\5Wed \o%“e S\.ar\°“ f `Wg~g- ’ '~-'_' ef ‘ S_ international long-distance lines. The new line will act Yd\W,@1 \° Co PS, _ tunnel in V' as the central north-south connection between G P`\“D,o.A\\\\ mining method5, Kreuz rankfuner Scandinavia, Benelux and the UK in the north and Frankfurt/Main Airport J; Switzerland, Austria, Italy and Greece in the south. With - 1-6, km E? gpggd railway a maximum speed of 300 km/h travelling time for :T to Mannheim passengers will be reduced si gnificantly. At the central Figure l. Tunnel "Frankfurter Kreuz“. hub ”Frankfurter Kreuz” two highways are undercrossed. The tunnels are constructed by open cutting method as well as by mining method and by Main runs parallel to the ”Autobahn A3”. A new long top-down method. At the same time the run of the distance station is constructed at Frankfurt/Main airport. motorway is changed at ”Frankfu1'ter Kreuz”. Also the The line runs east of this new station in a tunr1el_ ln the undercrossing of downtown Frankfurt/Main by along area ofthe Frankfurt highway intersection a level-free distance railway tunnel is planned in the context ofthe branching southward in the direction of Mannheim and so-called proj ect ”Frankfurt 2 l ”. northward into the direction of Frankfurt/Main central station takes place. The tunnel project is situated in the northern Upper 2 TUNNEL”FRANKFURTER KREUZ” Rhine Graben, actually in the area of the so-called Kelsterbach deep block. In the Frankfurt airport area 2.1 Situation - ground ana' ground-water conditions the elder Pleistocene Main sediments in the west, at Deutsche Bahn AG builds the new high speed railway the Kelsterbach connection, reach thicknesses of 33 m line Cologne-Frankfurt/l\/Iain. The ”FrankfLu'ter Kreuz”, to 44 m under the ground surface and in the east, at the which is situated in the immediate vicinity of the Frankfurt highway intersection, 22 m to 29 m under Frankftut/Main airport between the highway ”Autobabn ground surface. Below the elder Pleistocene Main A3”, the four lane road B43 and the US-housing estate sediments follow Pliocene sediments with thicknesses Gateway Gardens, is undercrossed in several tunnels of 100 H1 to l4O m. The top layers mainly consist of up (Fig. 1). to l m thick younger Pleistocene fine- to medium The new high speed railway line Cologne-Frankfurt/ grained dune sand layers. In the area of the traffic roads carriageway slab "Autobahn A3" there are also fills, which reach thicknesses up to 8 m .... ..... _ ._.. ...... » ..~. .-,.‘ ...., ,... _ .,__..__.._ ._...._ .._._..._. _ _._..... ..... .._... _ in the area ofthe embankments. The Kelsterbach terrace consist of an alternating 1'm f' 1-Q'35 f-: ,_." `_-_Y -<.»- #§‘?5>Z.f§ ¢- < -'- -- --Z» _-$' -_ ,- _; _ _ - _' _ ’ _ -j »’£: “gf-fi'_ -V _ __ sequence of medium- to coarse-grained sands and __ j€§t_;gron;¢{j _mo-5 ¢OV¢f_______.__ ._ _ &€__¢_t_____mnS gravels. This is characteristicaly of fluviatile sediments. 1' - _, M .... I 'i'§;»< 7-5ii ~= V " Y _ _.... 1 V V' Below the elder Pleistocene Main sediments mainly .__u_~.,,__.__..___,_~____ __ _ _ _W __ ~~'"“'i sholcmm L top-~»---~ h<,<1<_¥rng ' __ ____ fine- and medium grained sands of the Pliocene with ""final_ , concrete ,, __ mum] _ lmmg. f'UPP0’f . _ " C011 ' x _ _ .__jg irregular wavy interfaces are deposited. In some parts ____.____~lmmg bench____ ___ invcr' . A 'V 3 '_ A' __f I' ` of the upper 10 m to 15 m of the Pliocene sequence ltfgitli 3l5 §'5 ll'1|=|l‘5|i'E|E|l l l:l=l¢l=lsl2lflrl; sl=l=l=lil1!al1 _' __ '34 layers of silt and clay with thicknesses of only some centimeters up to several decimeters do appear. The ground-water level lies at approximately 15 rn to 16 m below ground surface. The general direction _____ . of flow is directed to the north-west and north to the Main, but flow is also oriented towards wells west IiiID m and north ofthe railway line. Figure-"'"""` 2. Soil profile and longitudinal section. 2.2 Tunnelling method r.Y 1'ground " r" surface _" 1-,"' J" "¢¥""4' '- ~ ’ ’_' 1. r =' A 280 m long part ofthe tunnel situated in the Frankfurt ?f55;~'1§?»€ ei; n-_'fr ri _ 1"_ 7’ '_ "ff ._‘ " 7 .v 1 1 .V-. ‘Ev -_"vi " "'~: _ "FV ' ` Z, _` -~ `__é,‘.€_l1;:'“:flE""¢__ highway intersection area beneath the ”Autobahn A3” _;?";§é ~' _ -/__ ¢_§r..::§1%§f§,§u,{,i-4; _f;__fg.}‘ ' __ _ ‘ ‘!§¢ v!~1FfJ= "7*‘f Ti; was built in mining technique. The tunnel crosses the H ___,Q _ r - 1. ‘fsyv-:_ '_ }_>~_ _' _ iz- §:3.__.§:5'j1`f:__§'_'e ”Autobabn A3” in a smooth angle. A modified spread concrete method with a driving in several parts was ‘-'»/\».-,`=;;§;Q2"2 - : \' '.\;f= ;:: 'Zu /f' ._ chosen with spread concrete initial lining and trailing Sand/gravel T -'-'a;f'¢'>i4l"2¢S§; .1 ?G>i€-'Z S-T :fi final concrete lining. The tunnel construction is planned 1E2--> 2 _rer::::.f;;_=‘dn# ','Ff`_;', _.F ¥?F.5:.-'-_= Si2 -"Z +L' 4-_'EZ as a mouth-profile with a constant cross-section of 150 square meters. This shallow tunnel is driven with a minimum cover of 15 m. Surface settlement was ' ' limited to a maximum value of 5 cm. For fullfilling this _ _.,,f.__ ,.,,-ji.riff j_` ‘Gif »j“:*" -»’2.:7` ‘“ _ __;_~r_:rm¢».¢¢_rr~-=;§;f~>2_>rz@:A~r»¢'=.»z»; ififtp' " demand and in order to guarantee the safety ofthe tunnel ¢._§.wa=»:_5ra@*@fS““' _ '1 #__ _mv =- init*-~ pi `f`f"1 _ ` A \ and to protect the staff from material falling down %‘ -?§&1?€f’ C -=;~f¢,;_5=¢m_=~_¢ 4 additional constructive support for the driving was -»;r,¥i4 =2m;.i‘-,"=\‘r»A=‘T,i2*"*fl - -V _'_-» 4 , necessary. First the crown (top heading) is driven along the entire tunnel route under the protection of a securing Figure 3. Stability analysis forthe working face with jet grouted roof cover hurrying on ahead (Fig. 2). After rigid plastic computational model. the completion of a 14.5 m long jet grouted roof cover the crown drivage was carried out on a stretch of about 10.8 m. The length of the cuts varied between 0.8 m the crown~feet’s area. and 1.0 m. The tunnel’s bench and inverts lying in the To guarantee the stability of the crown all work was groundwater are excavated under the protection of a done with a supporting core and a plugged face by waterproof j et grouted floor cover. The bench and invert means of eight jet grouted columns. The constructive excavation with the closing ofthe spread concrete initial support consisting of Support core, jet grouted roof lining’s ring' was carried out after the cutthrough ofthe cover and jet grouted face columns was required to crown with lengths of up to 2 m. The 280 m long tunnel ensure the stability of the working face. In Figure 3 a line was subdivided into several drivage sections by possible failure mechanism ofa collapse is shown. This vertical jet grouted transverse bulkheads with distances failure mechanism is used for a stability analysis with of 30 m resp. 60 m. The tightness of this jet grouted a rigid plastic, empirical calculation approach (Belter floor was proofed with a test lowering in each et al., 1999). bulkhead. Because of the cementation of some gravel Following the course of each jet grouted roof cover in the bench the test lowering was not able to establish the crown was widened in a cone-like manner as the a safe statement about the thightness of the whole driving progressed.