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5 GEOTECHNIEK SPECIAL ICSMGE – September 2013

Contents

6 Full-scale field validation of innovative dike monitoring systemsdr.ir. A.R. Koelewijn / ing. G. de Vries / ing. H. van Lottum

9 A new equilibrium model for arching in basal reinforced piled embankmentsir. S.J.M. van Eekelen / ir. A. Bezuijen

12 Some special technics used in the North-South Lineir. G.A. van Zwieten

14 Magic on a square footir. B.J. Admiraal

16 Seismic ground prediction system on a tunnel boring machineing. R. Reijnen / dr.ir. G. Drijkoningen

18 Construction of the new A74 motorway at Venlo (NL)

Geosynthetic Reinforced Earth (GRE) used as bridge abutment and soil pressure reliefing. C.A.J.M. Brok / dipl.-ing. O. Detert

21 Stabilisation of unbound granular layers – reinforcement required?dipl.-ing. L. Vollmert / dipl.-ing. C. Psiorz

Colophon

GeotechniekSpecial 18th International Conference on Soil Mechanics and Geotechnical Engineering

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Editorial BoardAlboom, ir. G. vanBeek, mw. Ir. V. vanBouwmeester, ir. D.Brassinga, ing. H.E.Brinkgreve, dr. Ir. R.B.J.Brok, ing. C.A.J.M.Brouwer, ir. J.W.R.

Calster, ir. P. van Cools, ir. P.M.C.B.M.Dalen, ir. J.H. van Deen, dr. J.K. van Diederiks, R.P.H.Graaf, ing. H.C. van de Gunnink, drs. J. Haasnoot, ir. J.K.Hergarden, mw. Ir. I.Jonker, ing. A.Kleinjan, ir. A.

Langhorst, ing. O. Mathijssen, ir. F.A.J.M. Meinhardt, ir. G. Meireman, ir. P.Rooduijn, ing. M.P. Schippers, ing. R.J. Smienk, ing. E. Spierenburg, dr. Ir. S. Storteboom, O.Vos, mw. Ir. M. de Velde, ing. E. van der

EditingBeek, mw. ir. V. vanBrassinga, ing. H.E.Brouwer, ir. J.W.R.Diederiks, R.P.H.Hergarden, mw. Ir. I.Meireman, ir. P.


IntroductionThe IJkdijk (Dutch for ‘calibration dike’) is a Dutchresearch program with the two-fold aim to test any kind of sensors for the monitoring of leveesunder field conditions and to increase the know-ledge on dike failure mechanisms. Since 2007, several purpose-built dikes have been brought to failure at the IJkdijk test site at Booneschans, inthe North-East of the Netherlands. Past experi-ments include a large stability test (Zwanenburg etal. 2012) and four field tests on backward seepageerosion or piping (van Beek et al. 2011). The testspresented in this article include these and otherfailure modes. For the near future, a test on staticliquefaction is planned.

Meanwhile, the outcome of these tests has beenimplemented in practice by instrumenting severalregular dikes, i.e. embankments with the functionto protect the hinterland against flooding. By theend of 2012, this advanced surveillance by sensorequipment had been placed in ten different dikesin the Netherlands, United Kingdom, Germany andChina.

The main purpose of the All-in-One Sensor Valida-tion Test (AIO-SVT) was to test the predictivepower of full-service dike sensor systems, i.e. sensor in and on dikes combined with data proces-

sing and an information system providing a timely,reliable warning in case failure may occur. The application of such systems into practice will be amajor improvement to the current state-of-the-artof dike management. In addition, contributing sensor systems were also tested and validated ontheir own. Another reason to carry out this test, inaccordance with the two-fold aim of the IJkdijk, isto learn more on dike failure mechanisms, includingfailure prevention methods. The AIO-SVT involvedthree dikes, which were all brought to failure. First, the geotechnical design of one of the dikes isdescribed, viz the South dike, followed by its instrumentation. Next, the results are described,first regarding the failure of the dike, then for the monitoring systems and for the informationsystems. Finally, conclusions are drawn. The full experiment, including the other two test dikes, is described in Koelewijn et al. (2013).

Design of the experimentsThe experiments were designed in such a way that each dike could fail to different failure modes.The duration of each experiment was planned to beat least several days, with a maximum of one week,to allow the participating companies to collect a reasonable amount of data under varying condi-tions.The South dike was built on a 4.5m thick composi-

tion of soft peat and clay. After construction, it was 4m high, 50m long at crest level, with a crestwidth of 3m and side slopes of 1:1.5 (V:H). Thecore was made of sand, with a 0.5m thick clay layer.Figure 2 shows a cross-section of the dike at thestart of the test, i.e. after consolidation resultingin a settlement of 0.99m.

The designed failure modes of this dike were slopestability with a deep sliding plane through the subsoil with a minimum deformation of 20cm andrupture of the clay cover by high pore pressures inside the sand core as a result of saturating thiscore with water.

InstrumentationFor the instrumentation a clear distinction is madebetween the reference monitoring and the instru-ments of the participating companies. The refe-rence monitoring was required to closely monitorthe course of the tests, while the other instrumentswere validated and the measurements were usedto make updated predictions of the failures.

A total of nine companies participated with theirinstruments – some in all tests, others in only oneor two. Each of these companies were invited to use their own measurements to give an initialprediction of the failure mode and the conditionsat which failure would occur, and to update thisprediction at least every 24 hours.Three companies providing dike safety informationsystems participated in all three tests. These com-panies had access to the data of the monitoringsystems being validated through a central database. The data of the reference monitoring was notdisclosed during the tests.

The reference monitoring at the South dike consis-ted of 34 pore pressure meters and six automaticinclinometers. Twenty-six pore pressure meterswere installed in two cross-sections each 13m fromthe centre line, as indicated in figure 2, six porepressure meters were installed in six water tanks


dr.ir. A.R. KoelewijnSpecialist R&D

Deltares

Full-scale field validation of innovative dike

monitoring systems

Figure 1 - Cross-section of South dike at start of test, showing settledgeometry and indicating positions of reference monitoring.

ing. G. de VriesGeotechnical

ConsultantDeltares

ing. H. van LottumSenior Geotechnical Consultant, Deltares

All illustrations are property of Deltares.


on top of the crest and the remaining two were installed in the basin on the non-failing side of the dike and in the ditch which was excavated during the test to reduce the overall stability. Theinclinometers were distributed along the centreline and both instrumented cross-sections.

The seven companies participating in this test in-stalled the following equipment:- glass fibre optics woven into geotextile, measu-ring temperature and strain approximately everymetre in three parallel lines along the whole lengthof the dike, on ground level and on two higher le-vels;- a system of six extremely accurate inclination in-struments,each mounted on top of a 5.6m steel rod placed onthe slope of the dike (three on the side of the failure, three on the other side);- a Fast Ground Based Synthetic Aperture Radarsystem, measuring a two-dimensional displace-ment field of the slope at the side of the failure

every five seconds;- a total of four tubes measuring temperature andstrain profiles over depth employing glass fibre op-tics: two vertical tubes 5.5m long halfway the slopeat the side of the failure, one vertical tube 3.5mlong at the toe at the same side in the centre lineand one horizontal tube along the whole toe of thedike;- a thermic infrared camera facing the downstreamslope, with a resolution of 640x480 pixels and anaccuracy of 0.05 K;- one controllable drainage tubes with measure-ments of pore pressure, temperature and dis-charge, located inside the sand core, close to thetoe at the side of the failure;- eight instruments measuring pore pressure, tem-perature and local inclination distributed over twocross-sections 10m away from the centre line, ineach cross-section one instrument in the sand coreclose to the toe and three instruments distributedover depth in the soft soil deposits under the toe.

Results of the testThe test on the South dike started on September3rd at 12:12 pm, by the infiltration of water intothe sand core. The next day, a small excavation wasmade in front of the dike. This had a limited effecton the dike, as shown in figure 2 by the horizontaldisplacements at the toe of the dike. The next day,a final excavation was made and on the basis of slope stability calculations it was decided to

continue by hydraulic loading only. In order to ac-quire a lot of measurement data, several days weretaken to raise the phreatic surface in the sand coreand to fill the water tanks on top. Finally, failure occurred on September 8th, at 2:27 pm, after122.26 hours, see Figure 3.

Table 1 shows the results of slope stability calcula-tions at characteristic moments applying the models of Bishop (1955) and Van (2001). The latteris a geometrically more flexible variant to Bishop’smodel. The results correspond well to the defor-mation behaviour shown in figure 2: close to the critical value of 1, the deformations quickly increase. These results may even draw some suspi-cion, but it should be borne in mind that quite advanced soil investigations had been carried out prior to the test (Zwanenburg et al. 2011, Koelewijn and Bennett 2012) and detailed actualmeasurements of pore pressures were available.Moreover, the model by Bishop has already longago been described as surprisingly accurate forconditions close to failure (Spencer 1967).

Table 2 gives the measured values of the horizontaldeformations during the last phase of the test forall inclinometers except one at the East side, whichfailed. The pre-set deformation criterion for a suc-cessful test was exceeded at the moment the maxi-mum pore pressures were recorded.


AbstractThree large scale field tests on dikes have been carried out at the IJkdijk test sitein the Netherlands. Two tests involved piping, micro-instability of the sand coreand erosion from overtopping. Both dikes failed on micro-instability. The third

test involved slope stability with a deep sliding plane. The failure process of thisdike is analysed in some detail. All tests were done to validate monitoring systemsand dike safety information systems. Several systems performed well.

Figure 2 - Horizontal displacements at toe of dike until close to failure.

Figure 3 - South dike during failure: fracturing of slope of ditch.

Table 1 - Safety factors calculated for the South dike.Situation Date & Time Van Bishop

Dike completed June 26, 5:00 pm 1.46 1.50

Start of test Sept. 3, 12:12 pm 1.74 1.82

Before last excavation Sept. 5, 9:00 am 1.24 1.38

After last excavation Sept. 5, 5:00 pm 1.05 1.08

Start of last infiltration Sept. 8,1:53 pm 1.01 1.05

Max. pore pressures Sept. 8, 2:13 pm 0.92 0.95

Visible failure Sept. 8, 2:27 pm 0.94 0.98

Table 2 - Horizontal deformations measured by inclinometersaround failure, in mm.

Time East in toe Middle - crest Middle in berm West in berm West in toe

1:53 pm 115 145 160 140 135

2:13 pm 145 190 200 175 155

2:27 pm 180 430 470 310 320

2:30 pm 225 1450 1650 900 830


Performance of the monitoring systemsAll monitoring systems were judged by their accu-racy, range, density of measurements, measure-ment frequency, redundancy, robustness, time toinstall and adjust, processing time, interpretationand quality of prediction. Note that several of thesefactors are not only influenced by the instrumenta-tion, but also by the strategy adopted by the com-pany. It should also be noted that successfulapplication of any technique depends on the actualconditions and environment.

An extensive evaluation of the results by the abovecriteria indicated a good to excellent performancein this test of the tubes measuring strain and temperature profiles (the design could still be improved, however) and the ground based SAR (robustness to field conditions could be improved).The other systems performed as expected or worse.

Performance of the information systemsThe information systems were judged by their abi-lity to combine data of different sources, the appli-cation of various techniques and methods to arriveat meaningful information, the clarity of statementsand the quality of prediction.

Two companies performed well, one employing ad-vanced data driven modelling and anomaly detec-

tion to improve finite element calculations, theother one focusing more on an engineer’s approachemploying both modern technology and visual ob-servations to update their predictions during thetest.The third company restricted its efforts mainly toproducing all kinds of graphical presentations of themeasured data, but hardly combining data of diffe-rent sources.

ConclusionsThe South dike failed according to one of the de-signed failure modes. Instrumentation of sevencompanies was tested here, including a novel tech-nique to measure strain and temperature and fastground based SAR as promising new monitoringtechniques. Employing monitoring data led to animprovement of the prediction of failure, especiallyif different types of monitoring were used. It appea-red that real-time advanced modelling further im-proves the knowledge on the actual and expectedcondition of dikes.

AcknowledgementsAcknowledgements are made to Staatsbosbeheerfor providing the test site at Booneschans, theDutch Ministry of Economic Affairs, Agriculture andInnovation for the financial support and all partici-pating companies for their efforts.

References– Beek, V.M. van, Knoeff, H. and Sellmeijer, H.2011. Observations on the process of backward ero-sion piping in small-, medium- and full-scale experi-ments, European Journal of Environmental and CivilEngineering 15(8), 1115-1137.– Bishop, A.W. 1955. The use of the slip circle in thestability analysis of slopes. Géotechnique 5 (1), 7-17.– Koelewijn, A.R. and Bennett, V.G. 2012. Leveefailure prediction competition 2012, ijkdijk.rpi.edu.– Koelewijn, A.R., Vries, G. de & Lottum, H. van2013. Full-scale field validation of innovative dike mo-nitoring systems, Proc. 18th Int. Conf. Soil Mech.Geot. Eng., Paris.– Spencer, E. 1967. A method of analysis of the stabi-lity of embankments assuming parallel inter-slice for-ces, Géotechnique 17(1), 11-26.– Van, M.A. 2001. New approach for uplift inducedslope failure, Proc. XVth Int. Conf. Soil Mech. Geot.Eng., Istanbul, 2285-2288.– Zwanenburg, C., Haan, E.J. den, Kruse, G.A.M.and Koelewijn, A.R. 2012. Failure of a trial embank-ment on peat in Booneschans, the Netherlands. Gé-otechnique 62 (6), 479-490. �

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Design of basal reinforced piled embankmentsMany analytical design models for the design ofpiled embankments distinguish two calculationsteps. Step 1 is the arching behaviour in the fill.This “arching step” divides the total vertical loadinto two parts: load part A, and the ‘rest load’ (B+Cin figure 1). Load part A, also called the ‘arching’,is the part of the load that is transferred to thepiles directly. Calculation step 2 describes the load-deflectionbehaviour of the geosynthetic reinforcement (GR)(see figure 1). In this calculation step, the ‘restload’ is applied to the GR strip between each twoadjacent piles, and the GR strain is calculated. An implicit result of step 2 is that the ‘rest load’ isfurther divided into load part B, which goesthrough the GR to the piles, and part C, resting onthe subsoil, as indicated in figure 1.This paper focuses on calculation step 1 only andthus on the determination of the load distributionin the load transfer platform. The two most inte-resting results of the arching step are:1. The calculated value for the arching A (kN/pile)2. The load distribution of B+C (kN/pile)

Van Eekelen et al. (2012a, b and 2013a, b) showedthat introducing a GR in a piled embankment results in a more efficient transfer of load to thepiles in the form of an arching mechanism. Theload B+C is then concentrated on the GR strips between each two adjacent piles, and the load distribution on these strips approaches the inver-sed triangular shape, as shown in figure 1 (righthand side of the figure). The concentration of load on the strips betweenthe piles is only found for GR basal reinforced piledembankments, not for piled embankments without GR. Therefore, it is necessary to make a distinction between arching models for piledembankment with and without GR. This paper focuses on GR reinforced piled embankments only.

Equilibrium models describing archingIn equilibrium models, an imaginary limit-statestress-arch is assumed to appear above the void (in this case the GR) between stiff elements. In the3D situation these stiff elements are piles, in the2D situation they are walls. The pressure on the GRis calculated by considering the equilibrium of thearch. In most models, the arch has a thickness.

The model of Hewlett and Randolph (1988, see figure 2) is adopted in the French ASIRI guideline(2012) and suggested in BS8006 (2010) as an alternative for the originally empirical model inBS8006. Another frequently applied equilibriummodel is the model of Zaeske (2001, also descri-bed in Kempfert, 2004). See figure 3. This modelis adopted in the German EBGEO (2010) and theDutch CUR226 (2010), and is hereafter calledEBGEO. Both models are further explained in VanEekelen and Bezuijen (2013c) and calculate thepressure on the subsurface below the arches in onepoint. They then assume that this pressure is the same everywhere between the piles, resultingin an equally distributed pressure on the GR.

Figure 4 shows a new model, which is the concen-tric arches model presented by Van Eekelen et al.(2013b). It is an extension of Zaeske (2001) andHewlett and Randolph (1988).

Concentric ArchesIn the concentric arches model, 3D concentric arches (hemispheres) occur above the square between each four piles (Figure 4). These hemis-pheres exert part of the load to their subsurface,the GR square between the four piles. The rest ofthe load is transported laterally in the direction of the GR strips. The load is then further transportedalong the 2D arches, in the direction of the pilecaps. The 2D arches also exert part of the load to their subsurface (the GR strips). Thus, both the3D hemispheres and the 2D arches exert a load onits GR subsurface, and this exerted force increasestowards the exterior. The part of the load not resting on the GR is the load on the piles (arching A). Following Hewlett and Randolph (1988), the radialstress �r and tangential stress �

�in the 2D

ir. S.J.M. van EekelenDeltares, Unit Geo-Engineering

and Delft University of Technology, Netherlands

ir. A. BezuijenGhent University, Belgium and unit Geo-Engineering

Deltares, Netherlands

A new equilibrium model for arching in basal reinforced

piled embankments

Figure 1 – Calculating the geosynthetic reinforcement (GR) strain comprises two calculation steps.

9

AbstractSeveral analytical models are available for describing arching in basal reinforcedpiled embankments. Between them are limit state equilibrium models. Two ofthem are frequently applied in Europe. One of them is the model of Zaeske (2001).The other model is the model of Hewlett and Randolph (1988). This paper consi-

ders these two models along with a new model: the Concentric Arches Model (Van Eekelen et al. 2013b). This model is an extension of the first two models. The paper gives a graphical presentation of the three models and validates themwith numerical calculations and field measurements.

GEOTECHNIEK SPECIAL ICSMGE – September 2013



Figure 5 – Concentric Arches model: resulting load distribution (kPa) for the Woerden case of figure 7a.

and 3D arches are calculated by assuming radialequilibrium of the crown element and assumingthat:– The principal stresses follow the arches with �

�

the major principal stress and �r the minor princi-pal stress. – The arches are in a nearly-plastic situation:

Where Kp (-) is the Rankine passive earth pressurecoefficient and � (o) is the friction angle. The forces exerted on the subsurface (the GR) are calculated by integrating the tangential stress over the GR area. This is fully elaborated and presented in Van Eekelen et al. (2013b). The resul-ting load distribution in figure 5 shows that theload is indeed concentrated on the GR strips, andthe load distribution on the GR strips indeed approaches the inversed triangular load distribu-tion found earlier in model tests, numerical analy-sis and field measurements (Van Eekelen et al.,2012a, b and 2013a).

Results and discussionBoth Hewlett and Randolph (1988) and Zaeske(2001) determine the pressure exerted on the GRat the central point between four piles only. Theycontinue with assuming that the entire GR area isloaded with this pressure, thus resulting in anequally distributed load on the GR. The concentricarches model, however, gives a load distributionthat resembles the observed load distribution: a concentration on the GR strips between adjacentpiles, and approximately an inversed triangularload distribution on the GR strips.

Hewlett and Randolph (1988) and Zaeske (2001)compared their analytical model with measure-

Figure 3 –Zaeske (2001) considers the equilibrium of the crown elements of the 3D concentric scales.

Figure 4 –Van Eekelen et al.(2013b), the newconcentric archesmodel. The load is transferred along the 3D hemispheres towards the GR strips and then via the 2D arches towards the pile caps.

Figure 2 – Hewlett & Randolph (1988) consider the ‘crown’ element of the 3D hemisphere,resulting in Acrown and the ‘toe’ element (just above the pile cap) of the plane strain arch, resulting in Atoe, as indicated in this figure. The lowest A is normative.


ments in scaled model tests without GR. Since weconsider models to design the GR, and since theapplication of GR has a large influence on the arching mechanism, it would be better to comparewith measurements in situations with GR. Figure 6 compares results of the considered analytical models with numerical calculations of Le Hello et al. (2009) and figure 7 with two casesof field measurements (Van Eekelen et al., 2012cand Van Duijnen et al., 2010). In these figures H (m) is the embankment height, a (m) the (equi-valent) width square pile cap, d (m) the (equi-valent) diameter of circular pile cap, sx andsy (m) the centre-to-centre distance of the pilesalong and across the road, sd (m) the diagonal centre-to-centre distance piles, � (kN/m3) the unit fill weight, p (kPa) the surcharge load and � (o) the friction angle.

The figures, as well as most other comparisons in Van Eekelen et al. (2013b), show that the concentric arch model agrees best with the nume-rical calculations, and most measurements in thescaled model tests. For the considered field test,the model of Zaeske and the new concentric arches model give comparable good results. Itshould be noted, that the measured arching A during the passage of the design load in Houtenwas higher than predicted with any of the analy-tical models, giving a safe design.

ConclusionsIt is important to make a distinction between models for piled embankments with or without geosynthetic basal reinforced (GR). In the casewith GR, the load is concentrated on the GR stripsbetween the piles (and the piles), and the load distribution on the GR strips is inverse triangular.This paper deals with the situation with GR.The models of Hewlett and Randolph (1988) as well as Zaeske (2001) result in an equally distri-buted load on the GR between the piles. The

concentric arches model (Van Eekelen et al.2013b) finds a load concentration on the GR strips, and approximately an inversed triangular load distribution on those GR strips. This is more in accordance with observations in scaled modeltests, numerical analysis and field measurements.The considered numerical calculations agree bestwith the concentric arches model. Measurementsin the field agree equally well with the concentricarches model and the model of Zaeske (2001).

AcknowledgementsThe financial support of Deltares and the financialsupport and fruitful discussions with manufactu-rers Naue, TenCate and Huesker is greatly appre-ciated.

References– ASIRI, 2012. Recommandations pour la concep-tion, le dimensionnement, l'exécution et le contrôlede l'amélioration des sols de fondation par inclu-sions rigides, ISBN: 978-2-85978-462-1 (in Frenchwith in the appendix a digital version in English).– BS8006-1:2010. Code of practice for strengthened/reinforced soils and other fills,BSI 2010, ISBN 978-0-580-53842-1.– CUR 226, 2010. Ontwerprichtlijn paalmatras-systemen (Design Guideline Piled Embankments),ISBN 978-90-376-0518-1 (in Dutch).– EBGEO, 2010 Empfehlungen für den Entwurf unddie Berechnung von Erdkörpern mit Bewehrungenaus Geokunststoffen e EBGEO, vol. 2. German Geotechnical Society, Auflage, ISBN 978-3-433-02950-3. (in German, also available in English,2011, ISBN 978-3-433-02983-1).– Hewlet, W.J., Randolph, M.F., 1988. Analysis of piled embankments. Ground Engineering, April 1988, Volume 22, Number 3, 12-18.– Kempfert, H.-G., Göbel, C., Alexiew, D., Heitz,C., 2004. German recommendations for reinforcedembankments on pile-similar elements. In: Pro-ceedings of EuroGeo 3, Munich, pp. 279-284.

– Le Hello, B., Villard, P., 2009. Embankmentsreinforced by piles and geosynthetics – Numericaland experimental studies with the transfer of load onthe soil embankment. Engineering Geology 106(2009) pp. 78 – 91.– Van Duijnen, P.G., Van Eekelen, S.J.M., Van der Stoel, A.E.C., 2010. Monitoring of a RailwayPiled Embankment. In: Proceedings of 9 ICG, Brazil, pp. 1461-1464.– Van Eekelen, S.J.M., Bezuijen, A., Lodder, H.J., van Tol, A.F., 2012a. Model experiments on piled embankments Part I. Geotextiles and Geomembranes 32: 69-81.– Van Eekelen, S.J.M., Bezuijen, A., Lodder, H.J.,van Tol, A.F., 2012b. Model experiments on piledembankments. Part II. Geotextiles and Geomem-branes 32: 82-94 Geotextiles and Geomembranes35: 119 and its corrigendum in Geotextiles andGeomembranes volume 32 (2012) pp. 82-94.– Van Eekelen, S.J.M., Bezuijen, A., 2012c. Does a piled embankment ‘feel’ the passage of a heavytruck? High frequency field measurements. In: proceedings of the 5th European Geosynthe-tics Congress. Valencia. Vol 5. pp. 162-166.– Van Eekelen, S.J.M. and Bezuijen, A., 2013a,Dutch research on piled embankments, Proceedingsof Geo-Congres, California, March 2013.– Van Eekelen, S.J.M., Bezuijen, A., van Tol, A.F., 2013b. An analytical model for arching in piled embankments. To be published in Geotextiles and Geomembranes.– Van Eekelen, S.J.M. and Bezuijen, A., A.F.,2013c. Equilibrium models for arching in basal reinforced piled embankments, In: Proceedings of the 18th Int. Conf. on Soil Mechanics and eot. Eng. Paris 2013.– Zaeske, D., 2001. Zur Wirkungsweise von unbewehrten und bewehrten mineralischen Tragschichten über pfahlartigen Gründungs-elementen. Schriftenreihe Geotechnik, Uni Kassel, Heft 10, February 2001 (in German). �


A NEW EQUILIBRIUM MODEL FOR ARCHING IN BASAL REINFORCED PILED EMBANKMENTS

Figure 6 – Variation of embankment height H,comparison analytical models with numerical calculations of Le Hello et al. (2009).

Figure 7 – Comparison calculated arching A with field measurements: (a) highway exit Woerden, Netherlands (Van Eekelen et al., 2012c) and (b) a railway in Houten, Netherlands (Van Duijnen et al., 2010).


IntroductionBecause of accessibility of the Amsterdam CityCenter, the city counsel decided for building ametro-line from the North to the South of Amster-dam. The line gets 8 stations and has a length of 9,7kilometers. It is expected the North-South line isready for use in 2017, and it will approximatelytransportate 200.000 travelers a day.VSF performed on the route of the line some spe-cial technics.

Work in compressed airAt Station Ceintuurbaan “de Pijp” and Station “Vij-zelgracht” compressed air is used for building thelast part of these deep stations. Both Stations hadto be digged out to a depth of about 30 meters. Toprevent cracking of the soil by upward pressure ofthe groundwater, work in compressed air is used.At both stations, work in compressed air wasthought of in the building specifications. At Vijzel-gracht, work in compressed air was reconsidered,and crossed off the scope. After some setbackswith leaks in the diaphragm wall, and settlementof the old weavershouses, the risk in the subsoilwas seen as a problem, so it would be irresponsibleto take the risk of failure. Station Vijzelgracht wasour second deep station for work in compressed air

in Amsterdam. VSF is the only experienced com-pany in The Netherlands for large building pits withthe use of compressed air.

VSF provided all the equipment for the compres-sed air work, as Compressor Station and Airlocksfor the personnel. The Airlocks for the digged out soil, rebar, concrete and equipement wherebuild by the main contractor, these were made ofconcrete. VSF provided also the medical support,operation of the airlocks and the compressor station and last but not least, continues control ofthe working chamber for the right pressure and health of the people below.

We installed 12 electric compressors to get theworking chamber in compressed air. As a backupfor the power supply, an emergency power supplywas installed. When this backup would fail or whenthere wouldn’t be enough air supply, 3 large diesel-compressors where present as a second back up. Tobe sure of good quality of air, air was filtered bytwo separate filter lanes. Entering the workingchamber was possible via the 3 airlocks for person-nel. In case of emergency, people in the workingchamber could escape via the 3 escape airlocks.There was a recompression tank available on site,

for treatment of possibility of decompression illness.

All personnel got a health inspection, and when healthy for the job, a dive approval. The airlock attendants are skilled and experienced personnelwhich had a MAD-A training. They looked afterabout 16000 ‘dives’ at Vijzelgracht and Ceintuur-baan.

Some figures:Working Chamber at Ceintuurbaan: 26000 m3

Working Chamber at Vijzelgracht: 54000 m3

CaissonsinkingOn another location, ‘Het Natte Damrak’ in frontof the Central train station of Amsterdam, part ofcanals of Amsterdam. VSF performed the pneuma-tic sinking of 3 caissons. Before start of buildingthe caissons, first a sheetpile wall is installed in thecanal and the building location is purged for debrison the canal bottom and wooden piles of old quaywalls. A Workisland was made in between thesheetpile wall, to build the caissons with the cutting edges.

The First and biggest caisson had to be sunken to a


ir. G.A. (Gerard) van ZwietenProjectmanager at

Volker Staal en Funderingen bv

Some special techniques used in

the North-South Line

Figure 1 – Control panel. Figure 2 – Pneumatic sinking.


depth of 25 m below surface. With measurementsof 58 m in length and 18 meters wide. This caissonis also a bridge foundation and startpit for the tun-nel drilling machine, it is sunken down in 2 partsbecause of its tallness. Two of the caissons are sunkdown in 2006, and the last one in between in 2012.The large gap in time has to do with traffic conti-nuity over the old bridge and local environment.

Method of Sinking down is using several hydraulicejectors and pumping out the wet subsoil. By undermining its own foundation, the caissons arecontrolled sunken. People working below workalso in compressed air. After about 12 meters anew forest of 150 wooden piles were discovered,it appeared to be all driven through piles. Caissonsare parked with an accuracy of 20 mm to the goalposition, the working chambers are concretedfor mass to avoid buoyancy.

GroundfreezingAll Caissons were in position, but had to be connec-ted. VSF got the contract for this in combinationwith the caissonsinking. Caisson were all positio-ned about 60 cm one-to-the-other. One had to beconnected to a diaphragm wall.

Freezing method used is liquid nitrogen with atemperature of minus 196 degrees Celcius, the horizontal freezing tubes were embedded in thepoured concrete, also a lot of temperature measu-ring points. The vertical freezing tubes are installed with a drill rig. Freezing in of the soil isdone in about 2 weeks, removing the bulkhead andsubsoil and installing the rebar and concretingtook about 3 weeks per joint. In this period about1 or 2 tanktrailers a day were on the job, each jointwas about 120 m3 of frozen soil. �


Figure 5 – Frozen soil.

Figure 6 – Liquid nitrogen tank.

Figure 3 – Caisson before sinking. Figure 4 – Caisson after sinking.


In The Hague the famousmuseum Mauritshuis is un-

dergoing an extension of “only” 10 x 15 m2. Thecollection of the museum consists of masterpain-tings from mainly The Golden Age of the Netherlands in the 17th century, originally collec-ted by the former stadthouder Prince William V ofOranje Naussau. The location of the building is inthe centre of The Hague next to the houses of parliament and the office (‘The Little Tower’) of the prime-minister. So any disturbance of this historic environment should be avoided, like noise,vibrations, traffic collisions, etc.

Geotechnical the situation can be described as finesands except for a thin peat layer at minus 16 m. Allbuildings have foundation slabs and thus have nopile-foundations. Like in most places in the Nether-lands groundwater level is nearly the surface level.

The main renovation and extension of the museumtakes place in the underground and can defined asfollows.The existing 2 story storage cellar will be transfor-med into an underground entrance-hall. Thereforenew tension piles and strengthening of the struc-ture is needed. so the piles have to be made

through the floor, below the water-table.Under the Mauritshuis, directly adjacent to thecellar a lift shaft will be constructed in the ground.

Opposite of the museum an existing monumentalbuilding has come in possession and will be transferred into an extension of the Mauritshuis.The connexion will be made under ground and therefore a 2 story cellar-construction has to be made under the existing building.Under the road between the 2 buildings a cellar hasto be constructed in order to connect and to createa large hall for exposition purposes.


Magic on a square footir. B.J. (Bartho) Admiraal

Innovation Manager at Volker Staal en Funderingen bv


VSF made a winning bid by offering a robust design based on flexible use of several specialfoundation techniques, like permeation grouting,jetgrouting, cutter-soil-mixing, ground-anchorsand gewi-piles. Recognised knowledge, expe-rience and reliability forms a base for trust and cooperation with the client and his technical advisors. The wide range of equipment and available techniques makes it possible to use the best solution for every situation.

Each day several crews with tiny machines vanishedthrough the small entrees and stairways into theexisting cellars, coming up again at the end of theday. In the limited space they created the water-tight retaining walls. At the surface larger equip-ment could be used. After a period of 3 months working the E-day wasthere. Excavation of a building pit, especially withsuch techniques under these circumstances, is always exciting.

Due to the craftsmanship of all involved employeesalso this project was a success. The excavationcould take place in a controlled way without significant leakages or building movements out of the tight limits. �


MAGIC ON A SQUARE FOOT


The Dutch company MI-Partners and the TechnicalUniversity of Delft are two partners in the Euro-pean Consortium NeTTUN. NeTTUN stands for“New Technologies for Tunnelling and Under-ground works”. This consortium, led by the FrenchTunnel Boring Machine (TBM) builder NFM, consists of 21 companies and institutes from 9countries throughout Europe. Its goal is to signifi-cantly improve the drilling of tunnels. One of theseimprovements is to increase the safety of tunnelboring. Currently tunnel boring is done almostblind and hence, obstacles and change of soilstructure can lead to delays, soil collapse and even accidents. Therefore, MI-Partners and the TU Delft are developing technology that can make a map of the soil in front of the boring head.TU Delft has a lot of experience in seismic imagingwhereas MI-Partners uses its mechatronic know-ledge from the high-tech industry for this challen-ging task.

MI-Partners is a company based in Eindhoven that is active in mechatronic innovation. Its 30 employees develop innovative concepts for custo-mers active in high-tech areas such as the semicon-ductor industry, healthcare and for technical

research institutes. These concepts usually startwith the derivation of the specifications and endat a prototype level. Although the applicationchanges over various projects, they all have incommon that a high accuracy, a high speed or preferably both are needed. The knowledge MI-Partners has gained in working for customerslike Philips and ASML can also be used for the development of this soil imaging device.

Surface vibratorIt is not the first time that TU Delft and MI-Partners work together on seismic imaging. Thismethod is frequently used e.g. in the oil drilling industry to search for new oil fields. With this method, the surface of the ground is agitated and reflections of this agitation from the groundare measured with an array of sensors (usually geophones). This agitation can be done with dynamite, but its drawback is the fact that it damages the soil structure. Therefore, seismic vibrators are widely used that agitate the groundin a controlled, reproducible manner. Hereto,often hydraulic vibrators are used. However, thesehave a drawback that the hydraulics limit the useat low frequencies. Therefore, in the recent past

MI-Partners has developed a seismic vibrator forthe TU Delft that is based on electromagnetic actuation, see figure 1.

This vibrator can generate a wave force of 6700 Nover a frequency range of 2 to 200 Hz. The prin-ciple of electromagnetic actuation is widely usedin e.g. the semiconductor industry but is quite new in seismology. The benefits of this type of actuation are the fact that these actuators are veryaccurate and on the other hand they can offer awide frequency range. A schematic drawing of thevibrator is shown in figure 2. It consists of a baseplate of 200 kg on which the coils for the actuatorare mounted. The magnets for the actuators aremounted on a reaction mass that weighs 1000 kg.Accelerometers measure the acceleration of thebaseplate and the reaction mass. These data areused to compute the weighted ground force:

The knowledge of this force is needed in combina-tion with the data received from the geophones toobtain the image map of the soil.

Vibrator on a TBMFor the vibrator of the TBM a dedicated vibratorwill be developed using the knowledge obtainedfrom the surface vibration mentioned in the previous section. The main differences with thisTBM vibrator compared to the surface vibrator of figure 1 are summarized in table 1. This vibratorwill be mounted in the boring head of the TBM.Furthermore a range of sensors is also mounted onthe boring head to measure the reflections fromthe ground (figure 3). During excavation the vibra-tor and the sensors are retracted inside the boringhead to prevent damage. Every time a new map-ping is desired the vibrator and sensors are placedon the bore front and the measurements are performed. Each measurement is repeated severaltimes at several angles of the boring head.

MI-Partners will design and build a TBM vibratorand the protection and retraction system for boththe sensors and vibrator. TU Delft will develop thetranslation of the data that comes from the


Seismic ground predictionsystem on a tunnel

boring machine

ing. R. ReijnenMI-Partners

dr. ir. G. DrijkoningenTU Delft

Figure 1 – Photograph of the surface vibrator.Figure 2 - Surface vibrator schematically depicted.


sensors and vibrator into the image map of theground.

The biggest challenge is to combine the precisionequipment and sensitive measurement devicesinto the harsh environment of a tunnel boring machine. The vibrator and the sensors should haveto work accurately under a wide range of environ-mental properties. The local temperature andpressure can change over a wide range, and fur-

thermore all obstacles that are present in theground should not damage the vibrator and thesensors. Hereto, predictive modelling is used,where the behaviour of the system under these various circumstances is modelled e.g. in FiniteElement models.

At the end of this year a stand-alone prototypeTBM vibrator will be finished which will be testedin the field during 2014. At the end of 2016 the

system should be fully integrated onto the TBMwhich will lead to a safer way of making tunnels.

AcknowledgementsThis research is part of the NeTTUN project, whichreceives funding from the European Commission’sSeventh Framework Programme for Research,Technological Development and Demonstration(FP7 2007-2013) under Grant Agreement 280712.www.nettun.org �

Figuur 3 - Schematic picture of the vibrator and sensors mountedon the TBM. The force wave is sent by the vibrator and its reflec-tions are sensed in various ways depending on the soil structure.

AbstractThe Dutch company MI-Partners and the Technical University of Delft are two partnersin the European Consortium NeTTUN. This consortium consisting of 21 partners has the goal to significantly improve tunnel boring. MI-Partners and the TU Delft will develop a system that generates a map of the soil in front of the boring head. Using this map the tunnel boring process can be made more robust and safer.

Table 1 Surface vibrator TBM vibrator

Use Stand-alone In TBMEnvironment Atmospheric; open air >> 5 bar; > 50°C; dirtDimensions ‘Unlimited’ Limited by TBM dimensionsPositioning Manual Automatically; retraction

during excavationTypical mass Baseplate: 200 kg Baseplate: 50 kg

Reaction mass: 1000 kg Reaction mass: 80 kg

Uitgeverij EducomAsk for more information about advertisements and sponsorships (including interesting publicity packages): [email protected] Publishers, P.O. Box 25296, 3001 HG Rotterdam, The Netherlands.

www.uitgeverijeducom.nl www.vakbladgeotechniek.nl

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Construction of the new A74 motorway at Venlo (NL)

Geosynthetic Reinforced Earth (GRE) used as bridge abutment

and soil pressure relief

ing. C.A.J.M. BrokDirector HUESKER

Synthetic BVNetherlands

dipl.-ing. Oliver DetertEngineering Department

HUESKER Synthetic GmbHGermany

The construction of a new section of the A74 motorway near Venlo (Netherlands) will addressthe increased cross-border traffic, thus relievingthe pressure on the existing border roads. The A74is planned to link the A73 (NL) and A61 (DE) motorways, providing a rapid direct link betweenthe two neighbouring countries. The route of themotorway required the construction of severalnew bridges. In the search for an economical solution to integrate bridges KW 4, KW 4A andKW 5 into the landscape, the choice was made infavour of “Geosynthetic Reinforced Earth” (GRE)systems from HUESKER. The design calculationsfor these structures were undertaken in line withthe guidelines outlined in EBGEO 2010 for the design of geosynthetic reinforced earthworks.

Building structureThe individual bridges were erected using the‘wrap around’ construction method with Fortrac®

geogrids. This flexible construction method isespecially suitable for soft non-homogenous

subsoil conditions.

HaTe® nonwoven material was used as erosionprotection on the exposed area of the geogrids.Instead of lost formwork in the form of angledsteel reinforcement mesh, the KW 4 and KW 4Abridge abutments were erected using large panelformwork. This achieves particularly economicalbuilding progress and a flat slope face at the sametime.

The Fortrac® Natur GRE system functions as an approach ramp for the bridge structure of the KW 4, standing approx. 7.0 m high. It also relieves soil pressure on the abutment which is clad with concrete panels. The limits of the horizontal wall deformations and the intended fillmaterial, containing a high percentage of fly ash, required the use of a high tensile, low strainreinforcement which was also resistant to alkalineenvironments. Consequently, Fortrac® MP wasfound to be the most suitable choice of material.

The special properties of the polyvinyl alcohol(PVA), the yarn used in this product, ensure long-term resistance while complying with the permit-ted deformations.

KW 4AThis structure spans the Wilderbeek stream andalso allows animals to pass under the A74. One of the bridge abutments was constructed as a geosynthetic reinforced support structure usingthe Muralex® GRE system. The bridge superstruc-ture, which carries heavy goods traffic, was supported directly on the earthworks and wasreinforced by high-modulus, low-creep Fortrac®

MP geogrids. The tight time schedule to imple-ment the project required intensive preloading of the soft subsoil in order to reduce long-termsettlement to a reasonable level.

The maximum height of KW 4A is 11.0 m at theedges and 9.0 m at the support points. The spacingof the geogrid layers is a uniform 0.5 m. The

Figure 1 – The Muralex GRE system meets stringent constructionand architectural design requirements (typical bridge abutment). Figure 2 - KW 4A: Bridge abutment during construction.

AbstractThe measures taken on the A73/A74 demonstrate convincingly the use of innovative construction methods even with complex civil engineering structures.

As a result of positive experiences gained world-wide with the Muralex® GRE system, it can be expected that this cost-efficient construction method, which alsoproduces aesthetically pleasing designs, will gain greater acceptance.



Muralex® GRE system consists of a static suppor-ting GRE base and a slim facing steel grid construc-tion which can either be backfilled with stone orpreseeded soil. The design also permitted thestaggered placement of the steel grid construc-tion, thus preventing the detrimental impacts ofdifferent settlement rates between the claddingand the GRE. If subjected to damage caused by vehicle impact or other ‘unplanned’ loading, thesteel grid facing is easily replaced, as the claddingis non load-bearing.

KW 5KW 5 is also designed with a complex architectureand offers pedestrians and cyclists a safe means ofcrossing the A74. The Fortrac® Natur GRE systemwas used here to relieve soil pressure on the abutments. The embankments designed withextra-steep slopes minimised the area of land used and reduced fill import compared with non reinforced embankments.

Location A73/A74 at Venlo (Netherlands)Client Rijkswaterstaat – Ministerie van

Verkeer & WaterstaatContractor Dura Vermmer Divisie Infra B.V.

Groete Projecten A74Construction March – May 2011periodProducts Fortrac® 110/25-20/30MP,

Fortrac® R 200/30-30MP,Fortrac® R 400/30-30MP,Fortrac® 80/30-20T, 55/30-20T,HaTe® B 150 K3HaTe® BS 12Muralex® GRE �

Figure 3 - View of stripped formwork on front surface (KW 4).Figure 4 - Use of large panel formwork to aid installationof the KBE Muralex® system (KW 4A)

Figure 6 - Completed bridge abutment designed with KBE Fortrac® Natur.

Figure 5 - Preloaded bridge abutment designed with KBE Muralex®.


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The behaviour of unbound base courses is im-proved by the use of geogrids. The latest resultsfrom large-scale testing carried out by e.g. Cuelho& Perkins (2009) show the effects of different geogrid products as well as performance-relatedtests by e.g. Christopher et al. (2008). Some prod-ucts provide characteristics for an ideal support of a ductile behaviour of unbound granular layers and reduced rutting (figure 1).

Usually the behaviour of the reinforcement is

defined by the simplification of compound effectand membrane theory. The compound effect is the basis for the composite of reinforcement and surrounding soil while the membrane effectprovides the ability for absorbing tensile forces: - A product which provides only an outstandinginteraction with the surrounding soil can first

provide a beneficial stabilisation effect whenmovement of the grain structure takes place andshear-strain is restrained by the absorption of tensile forces.- A product which provides high tensile strengthto act as a membrane cannot mobilise its strengthif no interaction with the surrounding soil is given.The latter would only take place at great deforma-tion of the structure when the soil has already failed due to large shear displacements.

That leads to the logical conclusion: Both effectsfor themselves cannot provide stabilisation orreinforcement of the granular layer; it is the combination and interaction of both which results in the beneficial effects of a suitable reinforcement product (figure 2).

Not only thin and unpaved granular layers lead toplastic strains in the reinforcement product. Alsoin relatively stiff constructions (e.g. base courses

for paved roads) plastic strains are documented,also considering that these are relatively low compared to the elastic strains (Vollmert, 2013).The plastic strains are the result of the construc-tion stage (trafficking and compaction), when the bearing capacity of the layers is initially relativelylow and supplemented by plastic strains accumu-lated during service life.

To restrain the amount of plastic strains – evenwhen occurring at low strain of some per mill – the absorption of tensile forces is necessary and supplementary performance reliability of tensilestrength should be provided (figure 3). Relaxation and creep should be discussed to withstand even small plastic deformations.

The design goal for a good performance of a product is the optimal combination of the main parameters as interaction behaviour (by frictionand interlocking), radial stiffness and absolutetensile strength (to provide satisfactory robust-ness), even under long-term aspects. Therefore,effective and long-term reliable stabilisation of unbound granular soils and layers requires ben-eficial geosynthetic reinforcement as defined in international standards and regulations. �

dipl.-ing C. PsiorzBBG Bauberatung Geokunststoffe

GmbH & Co. KGEspelkamp, [email protected]

dipl.-ing L. VollmertBBG Bauberatung Geokunst-

stoffe GmbH & Co. KGEspelkamp, Germany

[email protected]

Stabilisation of unboundgranular layers –

reinforcement required?

Figure 1 - Outstanding performance of a biaxial geogrid in a performance-relatedtest setup (after Christopher et al., 2008).

Figure 2 - Definition of stabilisation with or without beneficial reinforcing effect.

Figure 3 - Radial stiffness of different geogridsand supplementary performance reliability.



Additional parameters measured in a single CPT

For 45 years A.P. van den Berg has been active in thedesign and supply of advanced equipment for onshore,

near shore and offshore in-situ soil investigation. A.P. vanden Berg can provide complete or partial systems includingpushing equipment, tools and data acquisition systems.A.P. van den Berg is recognized for its innovative strengthand supplies proven technology. The head office is basedin Heerenveen, The Netherlands. An extensive web of pro-fessional agents and representatives all over the world,market the knowledge and expertise of A.P. van den Berg.

The demand to build a comprehensive and accurate picture of the subsoil by using additional parameters fromin-situ soil investigation is increasing. For example it maybe required to derive the in-situ properties of both soilstratigraphy and soil elasticity to design a foundation thatis subject to vibration; or both the soil density and soilelectrical conductivity to allocate contaminated layers andpredict future distribution.

In general these parameters can only be acquired by separate systems (seismic, conductivity, magneto, etc.) andin subsequent tests. Apart from being time consuming, this

process may also negatively affect the accuracy of the information obtained.

The Icone and IcontrolThe engineers from A.P. van den Berg have developed ameasuring system which eliminates these drawbacks. Itconsists of a digital data logger “Icontrol” and a digital“Icone”, measuring the traditional CPT parameters: conetip resistance (qc), sleeve friction (fs ), pore water pressure(u) and inclination (Ix/y). The unique Icone concept combines strength and reliability and provides excellentvalue for money. The Icone is mechanically 40% strongerthan its predecessor, the analogue cone, and at the sametime more accurate, more reliable and easier to maintain.Calibration data is stored in the cone itself, so USB sticksare no longer necessary. With a minimal investment, thishigh quality data acquisition system can also be integratedin existing CPT rigs.

Icone now extendable with click-on modulesBy moving to smart digital communication, sufficient bandwidth over a thin flexible measuring cable was created to accommodate additional parameters, withoutthe need for changing cones, cables or control boxes. The Icone is easily extendable by click-on modules to measure addi-tional parameters in a single CPT test andany module is automatically recognized by the Icontrol,thus creating a true plug & play system. The modulesshown on the right are already available.

Curious?Visit our booth No. 55 on the 18th International Conferenceon Soil Mechanics and Geotechnical Engineering in Paris(France) from 2 to 6 September 2013. We will demonstratethe Icone with some of the click-on modules and can provide detailed information.

Click-on modules for A.P. van den Berg’s digital cone (Icone)


You can also contact us at:

www.apvandenberg.com

[email protected]

+31 513 631355


Seismic- Shear wave left, shear wave right and compression wave

- Elasticity modulus

- Poisson's ratio

Conductivity- Detection of sand/clay layers

- Tracking of saltwater-carrying layers

- Detection of contamination

Vane- Soil investigation in very soft soils

- Undrained shear strength

- Remoulded shear strength

Magneto- 3-dimensional detection of the magnetic field

- Detection of sheet piling, ground anchors and

unexploded objects


soft soil expertise

| |

Deltares is an independent institute for applied

research in the field of water, subsurface and

infrastructure.

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