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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 – Ng, Huang & Liu (eds) ©2009Taylor & Francis Group, London, ISBN 978-0-415-48475-6 Construction method, ground treatment, and conditioning for tunneling T. Hashimoto & B.Ye Geo-Research Institute, Osaka, Japan G.L.Ye Department of Civil Engineering, Shanghai Jiaotong University, Shanghai, P.R. China ABSTRACT: This general report reviews a selected group of papers of Session 2 which is related to “ConstructionMethod,GroundTreatment,andConditioningforTunneling”.Thepapersaredividedinto5groups based on their topics: (1) construction methods with case studies, (2) ground treatment, (3) load and pressure, (4)conditioningadditivesforEPB,(5)others.Beforereviewing,thegeotechnicalaspectsinthesefieldsarefirstly summarized, and then the essences of these papers are presented.The deficiencies and future developments are also discussed. 1 INTRODUCTION Table 1. Grouping of the papers in Session 2. Session 2 includes 19 papers from China, Japan, UK, Num.of the Netherlands, Germany, Iran, Slovakia, Argentina Topics papers Authors and Brazil. Especially, Tongji University, Shanghai 1. Construction methods 6papers and GeoDelft, the Netherlands contribute to present with case studies some papers respectively. It is because that Shanghai 1.1 Bored tunnel by (3) Bakker & Bezuijen and the Netherlands have been performed many tun- TBM(shield (A, B) He et al. nels during the past decade in the soft ground. These tunneling) papers are divided into 5 groups and 8 subgroups 1.2 Shotcrete method (3) Sfriso Guatteri et al. based on their topics, which are shown in Table 1. (mountain tunneling Fillibeck &Vogt Althoughallthesepaperhascontributedtosomespec- method, NATM) ifiedaspectofconstructionmethod,groundtreatment, 2. GroundTreatment 5papers andconditioning for tunneling, some papers with sig- 2.1 Ground freezing (2) Hu&Pi nificant importance are selected to be reviewed in this Fillibeck &Vogt GeneralReport.Thereviewwillbecarriedoutaccord- 2.2 Grouting (4) Guatteri et al. ing to the grouping of the paper. Before the review, Bezuijen & vanTol the geotechnical aspects in these fields are firstly Gafar et al summarized. Fillibeck &Vogt 3. Load and pressure 7papers 3.1 Lining pressure (5) Hashimoto et al. Talmon&Bezuijen 2 CONSTRUCTIONMETHODWITH Talmonetal. CASESTUDIES Bakker & Bezuijen (A, B) 3.2 Pressure onTBM (4) Bezuijen & Bakker 2.1 Bored tunnel byTBM Song&Zhou More and more practices of bored tunnels by TBM Bakker & Bezuijen bring forward more and more requirements for shield (A, B) tunnel. Table 2 displays the current trend of develop- 4. Conditioning 2papers Hajialilue-Bonab mentofshield tunnel based on the requirements from additives for EPB et al. (A, B) the world market of tunneling. 5. Ohters 3papers Deng&Zhang To meet these requirements, technologies of TBM Kuzme&Hrustinec are also developed at the same time. The recent Li et al. 99 Table 2. Current trend in shield tunneling. Longdistance 3km∼10km High speed excavation 300m∼1000m/month Deepexcavation 40m∼100m Large cross section 10m∼15mofdiameter Deformedcross section 2faces∼4faces, non-circular High durability of tunnel 100 years Cost performance Notcheapbuthighquality with reasonable cost Table 3. Geotechnical aspects for bored tunneling (shield Figure 1. Support pressures before, during and after the tunneling). “Blow out” at the 2nd Heinenoord tunnel (by Bakker & TBMtype Both of slurry and EPB type in the Bezuijen (A)). soft soil with ground water Applicable ground Soft to stiff clay, loose to dense sand, gravel Groundloss Possible to be controlled less than 0.1∼1%innormalcondition Face stability Needsomecontrolling technologies for each slurry type or EPB type Filling tail void Simultaneous grouting can reduce ground loss and give an uniform distribution of lining pressure Segmental lining Manytypesofsegmentallining have been developed development of TBM and its technologies are shown as following: Figure 2. Surface settlements; measured and back- – Durability ofTBM calculated with different material models (by Bakker & – Durability of cutter bits Bezuijen (A)). – Exchangeable cutter bits – Installation of linings, new segmental linings – Driving control system surface settlement were also displayed, shown in Fig- – Docking method ure2.Itwasconcludedthatforanadequateprediction – Backfill grouting of deformations it is important to model the grouting In the practice of bored tunneling by TBM, the pressureasaboundarycondition,incombinationwith geotechnical aspects shown inTable 3 are of the most the use of small strain material model. importance and should be well considered. As to the structure issues of the 2nd Heinenoord Bakker & Bezuijen (A, B) shared their invaluable Tunnel, Bakker & Bezuijen (B) investigated the crack- experiences and findings on shield tunneling in soft ing and palling that occurred due to construction load, groundobtainedinlasttenyears.Duringtheconstruc- see Figure 3. Then a large scale tunnel ring tests was tion of the 2nd Heinenoord Tunnel that is approxi- carried out, shown as Figure 4. By combining the mately in the middle underneath the river Oude Maas model tests as well as numerical tests, it was found intheNetherlands.Theyfoundoutthatbecause“blow- that the usage of kaubit in the ring joint was the main out” occurred during TBM driving under the river, reason.Thecompressionoftheflexiblekaubitstripsby face support pressure dropped within 15 seconds after jackingforceresultedinaslippingofdifferentsegment the cutter face working, shown as Figure 1.According piece, leading to local stress concentration and irreg- totheirinvestigation,theypointedoutthatfacesupport ular deformation. By replacing it with stiffer plywood pressureshouldbecontrolledbetweenlowerandupper plates,thedamagewasprevented.Theinfluenceofthe limits for situations with little overburden or the soil duration of plywood to the long-term behavior of tun- cover itself is relatively light. We also are interested in nel,however,isstillquestionable.Duringconstruction the “15 seconds”, which indicted that the front insta- of the first tube for the Westernscheldt Tunnel, they bility occured without any omen, a careful control of found out that high grout pressures and in absence of front pressure is necessary. Some analysis results of beddingmaycausethebucklingoftheTBM.Certainly, 100 Figure 3. Damage to the dowel and notch sockets during Figure5. Theverticalstressincrementin1.5maheadofthe the first 150m of construction of the 2nd Heinenoord tunnel opening face (by He et al.). (by Bakker & Bezuijen (B)). Figure 4. Large-scale tunnel ring testing (by Bakker & Bezuijen). someotherfactorsthatwerenotdiscussedinthepaper mayalsocauseTBMdeformation. He et al. studied the first application of DOT tun- neling in Shanghai. They conducted an in-situ test Figure 6. Dot shield tunnel run across the buildings to investigate the distribution of stress and displace- (by He et al.). ment around the tunnel. Figure 5 shows the vertical soil stress increment ahead of cutter face. Beauti- 2.2 Shotcrete method (Mountain tunnel ful distribution of vertical earth pressure increment method, NATM) and settlement troughs were observed. It is expected that more detailed information about the measuring Thegeotechnical aspects of shotcrete method (Moun- methods can be given out. They also reported a DOT taintunnelmethod,NATM)aresummarizedinTable4. shield passed under a five-floor building with a dis- The design and construction procedures of Metro tance of 1m successfully by careful operation, shown tunnels in Buenos Aires from 1998–2007 were as Figure 6. The main countermeasures were relative reported by Sfriso. The characterization of Buenos low advancing speed and extra backfill grouting. Airessoilsfortunnelingisoverconsolidatedcemented 101
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