ࡱ> BDCܥhW eLfLc|t|tt|t|t|t|t|$D}D}D}D}D}D}Z}.D}Z}6~~~~~~~~~~~-$̀DXht|~47~~~~~t|t|~}~~~~t|~t|~~XjI|&|t|t|t|t|~~~7~Use of Piezocone in Site Investigation for the Danube - Sava Canal M.Mulabdic Civil Engineering Faculty, Osijek, Croatia Z.Miklin Institute of Geology, Zagreb, Croatia A.Bruncic Civil Engineering Institute of Croatia, Zagreb, Croatia ABSTRACT: Extensive geotechnical and geological investigations were undertaken for the construction of the Danube - Sava canal in eastern Croatia. The route of this 60-kilometer long canal was investigated by combining traditional procedure involving drilling and sample testing with modern penetration techniques as used in soil testing. The investigation was made by cone penetration (CPT) with pore pressure measurement (piezocone) and by Marchetti dilatometer testing. This approach has proven to be quite rational. Stiff clays, being the most frequently encountered material, were additionally investigated at three test sites where correlation was established between parameters for penetration testing and those for borehole and laboratory testing. Based on extensive investigations, appropriate piezocone testing techniques are proposed, including the method for analyzing results from such testing for the design of the entire route. 1 INTRODUCTION The canal that would connect the Danube and Sava rivers and enable regulation of water regimen in the eastern Croatia, while providing an appropriate navigable waterway, has been for many decades in the focus of interest of local population and water industry experts. First ideas about canal construction emerged as early as 260 years ago and, since that time, numerous studies have been prepared to enable realization of this significant project. The design work on this multipurpose canal has been particularly intense over the past several years. This canal would in fact enable regulation of the ground water regimen, it would improve irrigation practices and would hence foster economic development of this region while also forming a significant transport link between the Mediterranean and other regions of Europe by means of the Rhine - Main - Danube Canal System. The total canal length is 61.5 km, the navigable depth is 5 m, and the greatest depth of cutting into the terrain is approximately 22 m. A number of canal-related facilities will be situated along the route (gates, inverted siphons, pumping stations) as well as several bridges to accommodate the existing road and rail traffic. The area in which the Danube - Sava multipurpose canal is to be built is made of sedimentary deposits from the Quaternary Period. These deposits are represented by loess formations of Pleistocene age, by marshy - continental loess, and by some older marshy sediments and Holocene formations along the Sava river where flood-plain deposits and younger marsh sediments are dominant. The highly plastic clay covers most of the region on the stretch from the Sava river to Vinkovci. The formation is related to isolated marshy areas and dates back to the final stage of the lake marsh deposition of Pleistocene and Lower Holocene ages. Fine-grained clastic materials and plant remains have been depositing in the calm marshy environment. From the lithological standpoint, these formations are dark-green and dark-gray clays and silts that are commonly called sapropel. The bottom of these formations is most often formed of sandy silt and light-gray silty sand of fluvial origin. The sand is cross-bedded with sandy tabular concretions and somewhat coarser material which is an indication that it has been deposited during an abrupt water inflow and this in significant quantity (postglacial floods). In this area, the thickness of lake sediments varies from 5 to 8 meters. The sand - silt materials, determined as the zone of leached loess, are situated at the depth ranging from -1 to -6 m which is an indication that the first zone of leached loess is linked with the second zone (Galovi & Muti, 1984). This sedimentary deposit contains a small quantity of CaCO3 and some incrustations made of plant remains, it is stiff and contains dark-brown rounded globules of iron and manganese substances in intercalations ranging from 2 to 3 mm in thickness. The leached loess is the result of Wrmian glaciation and action exerted by surface water on already deposited loess formations. This is the third year since the beginning of extensive geological and geotechnical investigations undertaken to enable establishment of design documents for canal construction. The program of investigations devised for this project took into account local soil conditions as well as possibilities offered by state-of-the-art geotechnical procedures for soil testing, so that two investigation categories were planned: a) borehole drilling with sample extraction and testing and b) soil testing through penetration procedures - static penetration CPT (cone penetration test) and testing with Marchetti dilatometer (DMT). In order to estimate reliability of interpretation of soil conditions as obtained by CPT and DMT, three test sites were selected as locations for extensive soil testing according to the program which consisted of both classical and penetration procedures. On the basis of comparative analysis of results obtained by these procedures, recommendations were made as to procedures to be used for interpretation of penetration tests needed in geotechnical analysis, taking into account generally accepted interpretation procedures and local features of the tested soil. 2 TESTING PROGRAM ON TEST SITES Combined investigations were made on three selected locations, according to the arrangement given in Figure 1. symbol 183 \f "Symbol" \s 14 symbol 183 \f "Symbol" \s 14 symbol 224 \f "Symbol" \s 14 symbol 196 \f "Symbol" \s 14 symbol 224 \f "Symbol" \s 14 symbol 111 \f "Wingdings" \s 11o symbol 111 \f "Wingdings" \s 11o Figure 1. Arrangement of boreholes on test sites, spacing between boreholes: 2 m: symbol 183 \f "Symbol" \s 14 - CPT with glycerine in filter; - CPT with fat in slot-filter; symbol 224 \f "Symbol" \s 14 - Marchetti dilatometer; symbol 196 \f "Symbol" \s 14 - borehole; symbol 111 \f "Wingdings" \s 11o - dynamic penetration; The objective of the testing was to: test the influence of CPTU testing technology on measured parameters and interpreted parameters estimate the influence of soil type behavior and ground-water level on pore pressure measurement during CPTU testing compare parameters obtained by CPTU, DMT and vane testing determine difference between parameters obtained in situ and in laboratory The CPT testing was performed with pore pressure measurement (piezocone - CPTU) and, at that, either glycerine in filter or fat was used. In the latter case, instead of filter, the pore pressure was measured by means of the small opening between the cone and friction sleeve. The probe produced by Geotech (Sweden) was used in this testing. This probe transfers signals from the sensor using high-frequency sound waves. The capacity of this piezocone is 50 KN, the tip base diameter is 10 square centimeters, and the filter is placed 5 mm above the tip base. The entire investigation program was realized by means of the Geotech 604D drilling rig, which has proven to be quite appropriate for on-site investigations of this type. The CPTU testing as performed for this canal project has shown that stiff clay, and especially the hard crust on the surface, disturbs pore pressure measurement by causing high negative pressures in the piezocone, which can lead to less accurate measurement results in deeper zones characterized by greater stiffness, where positive pore pressures are expected, and which can make impossible pore-pressure dissipation measurements and thus also the determination of soil consolidation properties. In fact, the investigation program envisaged CPTU testing with fat rather than with filter, as it is known that fat is less sensitive to influence of such negative pressures (Larsson, 1995, Elmgren, 1995). The depth of preliminary borehole, i.e. the length of piezocone passage through hard zone, was varied so as to estimate influence exerted by hard crust. The part drilled during preliminary boring was filled with water in which the probe was inserted and left for approximately 10-15 minutes so as to adjust to temperature. In order to estimate repeatability of testing each test was performed two times, starting from different depths. The pore-pressure dissipation was measured at the depths of 6 and 10 meters for each piezocone testing. 3 DESCRIPTION OF TEST SITES The test site No. 1 contains highly plastic clays of dark-green and dark-gray color. The formation of these clays can be related to isolated marshy areas, 4 m in thickness. The bottom of these formations is most often made of sandy silt and light-gray silty sand of fluvial origin, it is cross-bedded and reaches 7 m in depth. Highly plastic clays are found down to the 15 m in depth. In general terms, the clayey facies is dominant. In a relatively small area, there is a significant vertical and horizontal facies alternation, which points to the very formation of these deposits. The ground-water level is at 2.5 m. Figure 2. Basic soil properties at the test site No. 1 and development of resistance at the tip of the piezocone Clays are dominant at the test site No. 2 and, at the depth of 0.5 meters, an intercalation presenting a crust effect can be discerned. The formation of this crust can be explained by the fact that this area was elevated in the Pleistocene, which caused erosion of loess from this area. Clays are situated in the center of the oxidized zone, so that the limonite crust starts to form due to weathering of iron-containing minerals. According to geotechnical determination of boreholes drilled on test sites, clays are highly plastic, stiff, and contain limonite concretions. Clay is of very stiff consistency. The SPT resistance diminishes with depth. The ground-water level is at 5.5 m. Figure 3. Basic soil properties at the test site No. 2 and development of resistance at the tip of the piezocone The third test site lies in older marsh deposits. According to borehole analysis, the clay is represented down to 10.0 m in depth. At the depth of 10 to 11 meters, there is an intercalation of soft silty clay which lies on silty sand. Well-sorted sand formations have been registered during core determination. The base of these formations is formed of sand to sandy silt layers. The ground-water level is at 1.6 m. Figure 4. Basic soil properties at the test site No. 3 and development of resistance at the tip of the piezocone 4 ANALYSIS OF TEST RESULTS At each test site, the testing included four piezocone tests, two dilatometer tests, and undrained shear strength was tested by vane test in the borehole from which samples were extracted for laboratory testing. Regardless of different depths of preliminary drilling and regardless of whether glycerine or fat was used in pore pressure measurement, piezocone tests presented very good repeatability rate (Figures 2 - 4) in testing resistance at cone tip, sleeve friction, friction coefficient, but not in pore pressure testing. The influence of testing procedure and interpretation of CPTU tests is considered in following sections. 4.1 Influence of preliminary drilling and water level The CPTU was performed after 1 and 3 m of preliminary drilling. The pre-drilled part of the borehole was filled with water and the probe was left to adjust to temperature for a period of 10-15 minutes. At locations 1 and 3 the testing started above and under the ground-water level (GWL = 2.5 and 1.6 m; start point: 1.5 and 3 m), while both tests on the location No. 2 were initiated above the ground-water level (GWL = 5.5 m). The influence of preliminary drilling should be the greatest in case of pore pressure measurement, as the negative pressure in filter is generated quite strongly and rapidly during passage through hard unsaturated soil. The procedure with glycerine in filter did not provoke any significant difference in pore pressure measurement along the depth for different depths of preliminary drilling. 4.2 Influence of hard soil layers The hard crust drastically increases negative pressures in the piezocone. This makes it impossible to measure pore-pressure dissipation, while being quite harmful to pore pressure measurements in softer deposits that are encountered later on. An interruption of penetration, even if it is for only 10 to 15 minutes, as is the case with dissipation measurement, enables saturation of filter and more accurate measurement of positive pore pressures after the testing is resumed. In addition, this interruption allows the probe to cool down as it becomes quite warm due to significant friction in contact with hard soil which alters the probe response (temperature compensation problem). Tests in which fat was used instead of filter have shown the trend of significant pore-pressure increase in hard sediments near the ground surface, particularly when compared to testing with glycerin. 4.3 Influence of method in pore pressure testing The pore pressure was tested in two ways: with glycerin in filter or without filter but using fat (the so called slot filter, Larsson, 1995, Elmgren, 1995). Glycerin is used quite frequently instead of water as it is less sensitive to influence of unsaturated soil. When fat was used instead of filter, pore pressure values were less negative, but their positive values were quite different in character when compared to those measured with glycerin in filter. The fat can not describe little changes in small intercalations, which is something the glycerine does quite well. Investigations undertaken in the course of this project have shown that in harder deposits situated near the ground surface the test with fat gives an unexpectedly high pore pressure values, that the negative pressure recovers faster than in the case with glycerin, but also that the repeatability rate is lower (two equal tests give greater difference than in the case of glycerin). In tests with fat, positive pressure values are expected in layers below the hard and unsaturated ones, so that the measurement of pore pressure dissipation is more often possible. Nevertheless, the test with fat should be submitted to a more detailed examination in laboratory and in field - making at that comparisons with glycerin - so that its use can become more reliable. The principal advantage of fat, i.e. elimination of the filter-saturation problem, is hampered by its deficiencies such as inaccurate pore pressure measurement, inertia, sensitivity to slot design in the probe, and transfer of pressure values onto the sensor (viscosity of fat). 4.4 Soil type determination The basic objective of piezocone testing is to determine soil type behavior. As a rule, the soil type can successfully be defined by means of standard interpretation procedures. The difficulty occurs with the hard layer of coherent soil, particularly if it is an unsaturated layer situated near the ground surface (dry crust). In such cases, stiff clays can sometimes be recognized as silty or sand-silt formations. The coefficient of friction of less than 2% does not always point to a cohesionless soil, although all cohesionless soil types have had the coefficient of friction of less than 1.5%. A special attention must be paid to accurate measurement of sleeve friction so that the coefficient of friction can realistically reflect actual conditions in soil. 4.5 Undrained shear strength of soil The undrained shear strength of soil was determined at specified depths by vane test, as well as continuously - along the depth - by means of Marchetti dilatometer and piezocone.Comparative results are presented in Figure 5. The value of undrained strength as determined by DMT has always been lower than the value obtained by piezocone. The undrained strength in piezocone was interpreted as Nk = 16 (Larsson and Mulabdi, 1991). The comparison between qc and cu=0.5qu shows that the Nk value of these harder clays is situated at around 25. This means that the cu(CPTU) values should be reduced for approximately 35% if qu=2cu is accepted, and then they would become closer to cu(DMT) values. The undrained strength value determined by vane test in borehole was greater than cu(CPTU), particularly in case of very stiff clays (cu higher than 80 kPa), while difference was smaller in case of softer clay deposits. It may even be pointed to a certain inadequacy of vane test for testing undrained strength of stiff clays, because of deviation from failure model and due to presence of concretions in tested clay, which changes the way in which soil failure occurs and increases resistance to vane rotation. 4.6 CPTU and SPT comparison The tip resistance of the piezocone and the number of blows N (SPT) for the tested clays are compared on figure 6. Tentative correlation suggests that: qc (MPa) = N/5.5. This relationship can be used for preliminary analyses and is in accordance to what we found in similar clays on other locations. 4.7 Consolidation characteristics of clays Dissipation testing by means of piezocone is considered suitable for estimating the horizontal coefficient of consolidation. This value enables interpretation of permeability coefficient (Mulabdi, 1991). A similar procedure is recommended with DMT although this result is generally less representative than the CPTU testing. Coefficients of permeability in vertical direction were measured on laboratory samples and the values obtained were compared with values interpreted on the basis of CPTU and DMT for horizontal direction. The relationship between these values is presented in Figure 7. Figure 5. Comparison of undrained strength values determined by vane test in the borehole, piezocone and by Marchetti dilatometer Figure 6. Tip resistance qc versus number of blows N (SPT) for tested clays 4.7 Consolidation characteristics of clays Dissipation testing by means of piezocone is considered suitable for estimating the horizontal coefficient of consolidation. This value enables interpretation of permeability coefficient (Mulabdi, 1991). A similar procedure is recommended with DMT although this result is generally less representative than the CPTU testing. Coefficients of permeability in vertical direction were measured on laboratory samples and the values obtained were compared with values interpreted on the basis of CPTU and DMT for horizontal direction. The relationship between these values is presented in Figure 7. It is difficult to interpret the dissipation curve in hard soil as the first part of the curve becomes deformed due to redistribution of pressure around the cone. It is therefore necessary to determine the initial pore pressure u0 on the basis of the curve u-symbol 214 \f "Symbol" \s 12t (tangent on curve for u0(t0)) after which it is possible to calculate parameters that are required for interpreting consolidation and permeability coefficients. Comparison of results of interpreted permeability coefficient from CPTU and DMT testing with the vertical-permeability coefficient as determined by oedometer testing, is presented in Figure 7. The coefficient of horizontal permeability based on piezocone testing is about 10 times higher that the coefficient of vertical permeability based on oedometer testing. Considering that the coefficient of horizontal permeability is always greater than the coefficient of vertical permeability (depending on bedding, the relationship is 1.3-10), it can be concluded that piezocone can be used to estimate the permeability coefficient (and consolidation coefficient) with accuracy better than the mere order of magnitude. The DMT gives about 6-10 times greater permeability than the piezocone, but it is not considered as really successful in this testing. Figure 7. Comparison between the horizontal permeability coefficient based on in situ testing and vertical permeability coefficient determined in oedometer 5 CONCLUSION The following conclusions can be made based on testing performed on test sites : - piezocone is very useful for rapid and inexpensive determination of basic soil properties: bedding, strength and permeability, - the test repeatability is excellent, - it enables a more accurate determination of the boundary between individual lithological members, when compared to traditional mapping of geotechnical boreholes, - the test procedure influences the result: negative pore pressures developing in unsaturated hard soil exert a negative influence on measurements in softer deposits at greater depths; it is sometimes recommended to interrupt the test for 10 to 15 minutes so that the probe may "recover" after passing through harder deposits; in fact, the preliminary drilling should be undertaken until the ground water is reached and the test should start at that level; if that is not possible, glycerine in filter should be used; the glycerine in filter describes fine changes in pore pressure much better than the fat in slot; additional studies are needed as to the use of fat instead of filter as such use facilitates the testing but reduces the accuracy, - in procedures normally used to interpret type of soil on the basis of CPTU results, hard unsaturated coherent layers could be identified as sandy or silty layers, - the coefficient of friction for cohesionless soil is less than 1.5%, - undrained strength of soil interpreted from CPTU according to cu=(qt-symbol 115 \f "Symbol" \s 12sv)/Nk requires local calibration of Nk value; in investigations for soil types with cu<50 kPa, the Nk value of 16 was considered appropriate (which is in fact used according to many accepted interpretations), while for soils with cu>50 kPa the Nk = 25 is more appropriate (the values range from 18 to 30), - the following tentative relationship was established: qc (MPa) = N(SPT) / 5.5, - the pressure dissipation in piezocone is a good indicator of consolidation parameters (cv and k) in horizontal direction; as to interpretation based on short testing, it is necessary to establish the initial pore pressure according to curve u-symbol 214 \f "Symbol" \s 12t, - piezocone testing should be preferred in earlier stages of investigation and, based on its results, other necessary tests, which are usually more expensive and involve longer periods of drilling and sample testing, should be determined and performed. REFERENCES Baligh, M.M. and Levadoux, J.N (1986). Consolidation after undrained piezocone penetration. I: INTEPRETATION. Journal of Geotechnical Engineering, Vol.112, No.112, pp 727-745. Brki,M. Galiovi I. Buzaljko, R. 1989.Tuma za list Vinkovci.. Osnovna geoloka karta.1:100 000. Beograd. (in Croatian) Elmgren, K. 1995. Slot-type pore pressure CPT filters. Behaviour of different filling media. International Symposium on Cone Penetration Testing CPT 95, Linkoping, Sweden, Swedish Geotechnical Society, Report 3:95 Galovi, I. & Muti, R. 1984. Gornjopleistocenski sedimenti istone Slavonije. (Hrvatska). Rad Jugosl. akad. znan. umjetn.,411 299-356, Zagreb. (in Croatian) Hernitz, Z. 1970. Prilog poznavanju paleostrukturnih odnosa neogensko -kvartarnih sedimenata u irem podruju amca. Geol. vjesnik, 23, 55-67. Zagreb. (in Croatian) Hernitz, Z. 1983. Dubinski strukturno-tektonski odnosi u podruju istone Slavonije. Poseb.izd. asopisa Nafta, 1-221, Zagreb. (in Croatian) Jamiolkowski, M.,Ladd, C,.C, Germaine, J.T. and Lancellota, R. 1985. New developments in field and laboratory testing of soils. State-of-the art report, XI ICSMFE, San Francisko, Vol. 1, pp 57-152. Larson , R. 1995. Use of a thin slot filter in piezocone tests, International Symposium on Cone Penetration Testing CPT 95, Linkoping, Sweden, Swedish Geotechnical Society, Report 3:95 Larsson, R., Lsymbol 246 \f "Times New Roman" \s 12froth, B., Msymbol 246 \f "Times New Roman" \s 12ller B. 1995. Processing of data from CPT tests. International Symposium on Cone Penetration Testings, Linksymbol 246 \f "Times New Roman" \s 12ping, 4-5/10 1995, Vol 2., Swedish Geotechnical Society. Larsson, R. and Mulabdic, M. 1991. Piezocone tests in clay. Swedish Geotechnical Institute, Report No. 42, Linkping, Sweden. Marchetti, S. 1992. DMT Manual Update. Mulabdi, M. 1991. CPTU test in soft soils, PhD. thesis, Civil Engineering Faculty, University of Zagreb. (in Croatian) Muti, R. 1975. Sedimentoloka ispitivanja naslaga lesa iz okolice Vinkovaca, Naica i Valpova. Geol. vjesnik, 28, 269-286, Zagreb. (in Croatian) Muti, R. 1984. Aragonit u kvartarnim naslagama nedaleko akova u Slavoniji (Hrvatska). Geol.vjesnik, 37,105-115, Zagreb. (in Croatian) Robertson, P.K. and Schmertmann, J.H. 1988. Guidelines for Using the CPT, CPTU and Marchetti DMT for Geotechnical Design. Report Number FHWA-PA-87-024+84-24. National Technical Information Service, Springfield, VA. parica, M. Buzeljko, R.1987. Tuma za list Slavonski Brod. Osnovna geoloka karta.1:100 000. Beograd. (in Croatian) Thomas, C.I. (1987). Various techniques for the evaluation of the coeficient of consolidation from piezocone dissipation test. Oxford University, Depertment of Engineering Science, Soil Mechanics Report No.40. .AS0.ASOz423459:VWXYefSTpqrs  Uc uDUc]]cU]U] uDU]U]cU]cuDU]c]ch]cV]c]cK<=>?A''=*A*V,Z,j//22q66<=@0@AAABBBBeBfBBBBBBB;CMWMXMZM[M2Q6QWWWWWWWWWWWXXX]cuD]c]ch]cV]c]cU] uDU]U]TXX)Y*Y4Y:YYY6Z7ZSZTZUZVZV[X[c[d[\R\t\k]]]]]q^z^^^_ __`````````#a$a%a&aaaaaaaqbrbbbocpcqc~cccd$e>e^eIfJfLffuuD]`c ]`cV]c]cV]c]cuD]c]c]chECDOz{f +`abZaW|(((((((((((((( ((&  UKUKK%33333#|Q$$$$$''''=*B**U,V,[,,,,,,,f//P`EE   V3333% 3 4& 3 4/22m66<= @1@ABDDEEEE2F3F_FHHHHGIHIMIIIILN2Q7QQQQQ3RR     p p3 h3h333'RRSjVWVWXAYYZV[W[X[c[d[\\e]% h3 4h.h% h3 4h.h% h3 4h.h3p3e]^^^^^9__`e?% h3 4h.h% h3 4h.h% h3 4h.h% h3 4 h.h3% h3 4 h.h`arbbccb<% h3 4h.h% h3 4h.h' h,3 4h.0h' h,3 4h.0h' h,3 4h.0hc+deweIfJfKfLfh`]X33,30% h3 4h.h% h3 4h.h% h3 4h.h% h3 4h.hK$@$Normal3 ]a c"A@"Default Paragraph FontLcLfhf"f  !U)R1;C9LT\LcXf456|/Re]`cLf789:;<=249VXeSpr <>J;J=JTTT6WSWUW]]]]#^%^^^^Lc999999999999999997xfcg E:\VANC2.docXXXE:\CLANCI\VANCOU~1\VANCU21.doc@HP LaserJet 4LLPT1:HPPCL5MSHP LaserJet 4LHP LaserJet 4L@g ,,@MSUDOHP LaserJet 4L?\ad HP LaserJet 4L@g ,,@MSUDOHP LaserJet 4L?\ad 6N6N6N6NZTimes New Roman Symbol &ArialTimes New Roman CEWingdings"h_b5f_b5f[$F]Q)!hBUse of Piezocone in Site Investigation for the Danube - Sava CanalZoran VulelijaxfcgRoot EntryVcWcZc&((( F"ЏyJJWordDocument&  UKUKK%PfCompObj  jSummaryInformation (    !"#$%&'()*+,-./XFKILMNOQRSTUVWYZ[\]^_`abcdefghiE cLfhf"f  !F'),3<jEFgOX`cY, !!!$$$$$$$$$$ $!$"$#$$$F'G'H'I'J'K'L'M'N'O'P'Q'R'S'T'U'V'W'X'm)n)o)p)q)r)s)t)u)v)w)x)y)z){)|)}))EEEEEEEEEEEEEEEDocumentSummaryInformation8 Root EntryVcWcZc&((( F"ЏyJJWordDocument&  UKUKK%CompObj  jSummaryInformation (    !"#$%&'()*+,-./0123456789:;<=>?@AFI3DMicrosoft Word for Windows 95C@@Z=r@aI@\Jd R՜.+,0HPhpx  IGH, Zavod 20A* CUse of Piezocone in Site Investigation for the Danube - Sava Canal FMicrosoft Word Document MSWordDocWord.Document.69qOh+'0(< HT |   CUse of Piezocone in Site Investigation for the Danube - Sava CanalCCZoran Vulelija Normal.dotXXXEEEEEEEkFlFmFnFoFpFqFrFsFtFuFvFwFxFyFzF{F|F}F~FFFFXX:[c Xff456?|/Re]`cfff789:;<=@A249VXeSpr <>RJoJqJTTTjWWW]!^#^0^V^X^^^^c999999999999999997xfcg E:\VANC2.docXXXE:\CLANCI\VANCOU~1\VANCU21.doc@HP LaserJet 4LLPT1:HPPCL5MSHP LaserJet 4LHP LaserJet 4L@g ,,@MSUDOHP LaserJet 4L?\ad HP LaserJet 4L@g ,,@MSUDOHP LaserJet 4L?\ad :[:[:[:[!!!$$!$"$$$F'M'P'Q'S'V'X'm)p)}))EEEEEEkFpFFFXX:[~cc@@$@f@$@f@f@f@f@'@f@f@f@f@f@f@A*@f@f@Z,@,@f@f@f@f@f@H@f@f@f@MI@f@W[@^@KfZTimes New Roman Symbol &ArialTimes New Roman CEWingdings"h_b5ffb5f[$Fd R*gBUse of Piezocone in Site Investigation for the Danube - Sava CanalZoran VulelijaXXXܥhW eLffc|t|t$ :MZJ6-Xg47 JyJ$,P7Use of Piezocone in Site Investigation for the Danube - Sava Canal M.Mulabdic Civil Engineering Faculty, Osijek, Croatia Z.Miklin Institute of Geology, Zagreb, Croatia A.Bruncic Civil Engineering Institute of Croatia, Zagreb, Croatia ABSTRACT: Extensive geotechnical and geological investigations were undertaken for the construction of the Danube - Sava canal in eastern Croatia. The route of this 60-kilometer long canal was investigated by combining traditional procedure involving drilling and sample testing with modern penetration techniques as used in soil testing. The investigation was made by cone penetration (CPT) with pore pressure measurement (piezocone) and by Marchetti dilatometer testing. This approach has proven to be quite rational. Stiff clays, being the most frequently encountered material, were additionally investigated at three test sites where correlation was established between parameters for penetration testing and those for borehole and laboratory testing. Based on extensive investigations, appropriate piezocone testing techniques are proposed, including the method for analyzing results from such testing for the design of the entire route. 1 INTRODUCTION The canal that would connect the Danube and Sava rivers and enable regulation of water regimen in the eastern Croatia, while providing an appropriate navigable waterway, has been for many decades in the focus of interest of local population and water industry experts. First ideas about canal construction emerged as early as 260 years ago and, since that time, numerous studies have been prepared to enable realization of this significant project. The design work on this multipurpose canal has been particularly intense over the past several years. This canal would in fact enable regulation of the ground water regimen, it would improve irrigation practices and would hence foster economic development of this region while also forming a significant transport link between the Mediterranean and other regions of Europe by means of the Rhine - Main - Danube Canal System. The total canal length is 61.5 km, the navigable depth is 5 m, and the greatest depth of cutting into the terrain is approximately 22 m. A number of canal-related facilities will be situated along the route (gates, inverted siphons, pumping stations) as well as several bridges to accommodate the existing road and rail traffic. The area in which the Danube - Sava multipurpose canal is to be built is made of sedimentary deposits from the Quaternary Period. These deposits are represented by loess formations of Pleistocene age, by marshy - continental loess, and by some older marshy sediments and Holocene formations along the Sava river where flood-plain deposits and younger marsh sediments are dominant. The highly plastic clay covers most of the region on the stretch from the Sava river to Vinkovci. The formation is related to isolated marshy areas and dates back to the final stage of the lake marsh deposition of Pleistocene and Lower Holocene ages. Fine-grained clastic materials and plant remains have been depositing in the calm marshy environment. From the lithological standpoint, these formations are dark-green and dark-gray clays and silts that are commonly called sapropel. The bottom of these formations is most often formed of saarson , R. 1995. Use of a thin slot filter in piezocone tests, International Symposium on Cone Penetration Testing CPT 95, Linkoping, Sweden, Swedish Geotechnical Society, Report 3:95 Larsson, R., Lsymbol 246 \f "Times New Roman" \s 12froth, B., Msymbol 246 \f "Times New Roman" \s 12ller B. 1995. Processing of data from CPT tests. International Symposium on Cone Penetration Testings, Linksymbol 246 \f "Times New Roman" \s 12ping, 4-5/10 1995, Vol 2., Swedish Geotechnical Society. Larsson, R. and Mulabdic, M. 1991. Piezocone tests in clay. Swedish Geotechnical Institute, Report No. 42, Linkping, Sweden. Marchetti, S. 1992. DMT Manual Update. Mulabdi, M. 1991. CPTU test in soft soils, PhD. thesis, Civil Engineering Faculty, University of Zagreb. (in Croatian) Muti, R. 1975. Sedimentoloka ispitivanja naslaga lesa iz okolice Vinkovaca, Naica i Valpova. Geol. vjesnik, 28, 269-286, Zagreb. (in Croatian) Muti, R. 1984. Aragonit u kvartarnim naslagama nedaleko akova u Slavoniji (Hrvatska). Geol.vjesnik, 37,105-115, Zagreb. (in Croatian) Robertson, P.K. and Schmertmann, J.H. 1988. Guidelines for Using the CPT, CPTU and Marchetti DMT for Geotechnical Design. Report Number FHWA-PA-87-024+84-24. National Technical Information Service, Springfield, VA. parica, M. Buzeljko, R.1987. Tuma za list Slavonski Brod. Osnovna geoloka karta.1:100 000. Beograd. (in Croatian) Thomas, C.I. (1987). Various techniques for the evaluation of the coeficient of consolidation from piezocone dissipation test. 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