Geotechnical Problems of New Capital Astana (Kazakhstan)

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1 Geotechnical Problems of New Capital Astana (Kazakhstan) A. Zh. Zhussupbekov Professor of Geotechnical Institute, Eurasian National University, Astana, Kazakhstan Y. Ashkey, R. Bazilov, D. Bazarbaev, N. Alibekova & A. Zhussupbekov Ph.D. Students of Geotechnical Institute, Eurasian National University, Astana, Kazakhstan ABSTRACT: In this paper presented analysis of application of driven steel H-pile, bored piles through FDP (Full displacement piles) and CFA (Continues flight auger piles) technologies and described advantages for problematical soil conditions of Astana. Comparison results of field load tests of steel H-pile, FDP and CFA piles with traditional piles (precast driven piles and bored piles with casing pipe) was given in engineering geological conditions of new capital. 1 INTRODUCTION At present time pile foundations widely using for problematic soil grounds of structures. Such problematic soil grounds of in North Kazakhstan, from 1998 was known new capital city Astana, it takes area of km 2. Construction development of the capital city is important for the country which its aim is to be among of 50 developed countries. In this direction of our country foreign investors use their techniques and technology in big project constructions and constructions of high rise buildings and structures. At present time construction of pile foundation of the buildings in new capital of Astana (Kazakhstan), apply piles: precast square section driven piles; bored piles (with casing pipe, through technology of FDP and CFA) and driven steel H-piles. Steel H-pile, FDP and CFA piles are used first time for construction of the pile foundation of Kazakhstan. The steel H-pile has been accepted by designers at construction of Embassy of the USA in Astana [Bazilov 2005]. Both bored pile installation technologies (FDP, CFA) used with traditional bored piles for pile foundations of the high-rise building and structures in Astana. In following figures illustrated (1 to 4) are buildings of Astana (new capital of Kazakhstan), which used FDP and CFA piles, Entertainment Centre "Khan Shatyry", three apartments of Severnoe Siyanie, Palace of the Peace, three apartments of Emerald Towers and Transport Tower. In following figures are illustrated Mega-projects of Astana (new capital of Kazakhstan). Figure 1. Entertainment Centre "Khan Shatyry". Figure 2. Three apartments of Severnoe Siyanie. 2 ENGINEERING-GEOLOGICAL CON- DITIONS OF THE SITE 2.1 Construction Site of the USA Embassy The site of researches for construction is on the Southeast side of Astana the capital of Kazakhstan, on the right side of Esil river. The

2 territory of the city of Astana is located on the Kazakh Steppe on which the tectonic activities, that s why it appears to be safe for the construction purposes. Table 1. Physic-mechanical properties of site soil. E C φ R o ρ Type of Soil (MPa) (kpa) (kpa) (g/cm 3 ) Loam and clay Gravel Loam Grussrubble Aleurolites Construction Site of Two Apartments of Trade & Entertaining Centre Khan Shatyry Figure 3. Palace of the Peace. Figure 4. Three apartments of Emerald Towers. In geological structures of a site of researches take part: alluvium the modern adjournment presented by loams, clay with lenses of gravel sand and loam (EGE-1, 2), gravel soil (EGE-3); eluvial the formations presented by loams with inclusions gruss and rubble, sandstones and siltstone (EGE-4), grussrubble soil (EGE-5); and also eluvial formations middlejurassic the breeds, presented by aleurolites (EGE-6). All the before mantioned sediments are covering by a soil-vegetative layer from above. Results of physic-mechanical properties of soil the bases of construction site are resulted from top to down in Table 1. The site for construction is on the Southeast side of Astana, on the left side of Esil river. On the basis of the visual description of grounds and to the data of the skilled field works confirmed with results of laboratory researchers, division of grounds, researches composing the site on engineering-geological elements in their sequences of bedding (Table 2): EGE-1. Fill-up soil; EGE-2. Loamy soil, water saturated; EGE-3. Gravelly sand; EGE-4. Gravel soil; EGE-5. Loamy soil with inclusion gruss and gravel. Table 2. Physic-mechanical properties of site soil. Type of Soil E (MPa) C (kpa) φ ρ (g/cm 3 ) EGE EGE EGE EGE EGE FEATURES OF APPLICABLE PILES 3.1 Steel Pile Steel piles H sections of type HP12х74 (НР305х110), became made from high-strength low alloy colombia-vanadium of a class 50 (345) according to ASTM A572 Grade 50 (the

3 American standard) [ASTM 2004] Fig. 5. On an edge of a pile shoe from the strong steel tips НР-7780-В made Associated Pile and Fitting Corp (Clifton, state of New Jersey) weld. simultaneous filling a hole by concrete through an aperture the boring tool. Forth way: Installation of spatial reinforcing cage. Figure 5. Steel pile with a steel tip. 3.2 Bored Pile through FDP Technology This technology includes formation of a hole up to necessary depth by means special coneshaped boring tool, without excavation due to its compacting (lamination) a bottom of the hole and its lateral surface. Then concreting of this hole from bottom, by continues feeding of plastic concrete under pressure by means of concrete pump through the aperture in the boring tool, up to its full filling with concrete. Then installation reinforcing cage of the corresponding length. The shape of the pile is fulfilled in 4 ways (Fig. 6) [Zhussupbekov 2008]. Figure 7. Bored machine BG-20H for installation FD pile. 3.3 Bored Pile through CFA Technology Through technology of Continuous Flight Auger (CFA pile) is one worldwide technology which can be used as one solution of foundation construction. CFA piles have been more widely used and generally work well very stiff clay, loams, sands and well-graded sands (with bands of gravel). Soil condition of many regions in Kazakhstan is characterized above type of soil. Therefore, research and use CFA pile for pile foundations are necessary in soil grounds of new capital (Astana) of Kazakhstan. Figure 8. Bored pile through CFA technology. Figure 6. Bored pile through FDP technology. First way: Installation of the boring tool on a point, (Figure 7). Second way: Performance of a hole without of excavation of a soil due to its compaction (lamination). Third way: Extraction of the boring tool with The CFA construction sequence is comprised of five stages in Figure 8: The digging tip of the auger is fitted with an expendable cap. The auger is drilled into the ground to the required depth. Concrete is pumped through the hollow stem, blowing off the expendable cap under pressure.

4 Maintaining positive concrete pressure, the auger is withdrawn all the way to the surface. Reinforcement is placed into the pile up to the required depth (Figure 9). Figure 9. The pile drilling rig Bauer BG-20 through technology CFA. 4 INVESTIGATION METHOD 4.1 Steel Pile Before driving test steel piles have been marked every of 25 cm on all length (L=12.0 m). For driving steel piles used pile driving rig Junttan PM20 with hydraulic hammer ННК-4А part of blow with weight 4.0 tons Carrying out of dynamic tests of the first stage In Figure 10 it is shown directly, driving to steel pile LT-2 and carrying out of dynamic test. Figure 10. Driving test pile LT-2 with Junttan-PM20. In the first stage, steel piles were driving according to preliminary criteria for a stop: on 600 kn working loading, refusal of a pile should be equal 1.25 cm (25 cm/20 blows); on 400 kn working loading, refusal of a pile should be equal 1.67 cm (25 cm/15 blows). Table 3. Results of dynamic tests of the first stage. Number of pile Embedded deep in soil (m) Design load (kn) Refusal of pile at driving (cm) LT LT LT LT LT LT LT LT LT After "rest", steel H- piles driving with such refusals (see Table 3) were tested by static loadings Carrying out of static tests of the first stage Static tests were spent according to requirements of Standard ASTM D and of GOST , as object of research is the Embassy of the USA [ASTM 1981, GOST 1994 & SNiP of RK 2002]. Steel piles should be tested for a minimum 200 design working loadings, on 600 kn design loading to apply pressing loading 1200 kn, and on 400 kn accordingly 800 kn. At static tests the following equipment was applied: hydraulic jack SMJ-158А ton; caving in-measurers of the type 6ПАО. The pressure in the jack was created with the help of manual oil pump station MNSR-400 with power up to 800 kg/cm², the moving of steel piles was fixed by caving in-measurers of the type 6-PAO, which were positioned on both sides of unmovable bearings with the benchmark system. The first count out, performed right after putting the loading, then consequently 4 counts

5 out with an interval of 15 minutes, 2 counts out with an interval of 30 minutes and further for every hour until the conditional stabilization of deformation. Loadings were created by steps on 150 kn. For the criterion of conditional stabilization of deformation was taken the speed of settlement of boring piles on the given stage of loading that did not exceed 0.1 mm during the last 1-2 hours of observation. Steel piles required reactive efforts. Reloading was conducted in stages 300 kn. Carrying out of static test and results are shown in Figure 11 and Table 4. Figure 11. Test by static loadings of steel pile LT-8, L=15.0 m. Table 4. Results of static tests of the first stage. Embedded Refusal Settlement Number of pile at deep in soil of pile driving (m) (mm) (cm) Applied (kn) LT LT LT Diagrams of dependence of loading and settlements of steel pile by results of static tests of the first stage in Figure 12. The further test of other six piles had no sense as results of static tests have shown not satisfactory bearing capacity, and the decision about extension lengths of a pile was accepted (Figure 13) Dynamic tests of the second stage In the second stage steel piles driving, after extension lengths of a pile by electric welding, according to criteria for a stop: for 600 kn, refusal of 0.33 cm (25 cm/75 blows); for 400 kn, refusal of 0.83 cm (25 cm/30 blows). Settlement S, mm Load Р, kn Pile LT-1, L=7 m Pile LT-9, L=9.25 m 32 Pile LT-4, L=8.0 m Figure 12. Graph of dependences of settlements S from the loading P. Figure 13. Steel H - pile extension by welding Static tests of the second stage After extension lengths of piles and repeated driving them before refusals resulted above (item ), have been lead static tests of the second stage, their results are resulted in Table 5.

6 Table 5. Results of static tests of the second stage after augmentation. Embedded Refusal Settlement Number deep in of pile at Applied of pile soil driving (mm) (kn) (m) (cm) LT LT LT LT LT LT LT LT LT For the criterion of conditional stabilization of deformation was taken the speed of settlement of bored pile on the given stage of loading that did not exceed 0.1 mm during the last 1 hour of observation (Table 6 and Figures 15 and 16). 4.2 Carrying Out of Static Tests of the Bored Piles through FDP and CFA Technologies The technology of static loading test of bored piles was done in accordance with the requirements of GOST , i.e. according to the GOST requirements bored pile is tested after reaching its concrete strength of precast pile till 80% from total strength and for driving piles the test is provided after 6 day rest. Then both piles are tested on their concrete body integrity with the help of computer testing - FPDS SIT (Foundation Pile Diagnostic System Sonic Integrity Testing). The loads were made by three 2000 kn hydraulic jacks DG200P150 rest on anchoring supporting stand. The reaction force took by four anchoring bored piles (Fig. 14) [Zhussupbekov 2007]. The pressure in the jack was created with the help of manual oil pump station NRG-8080, load was controlled with the technical monometer MA100BU63. Measuring of settlement every pile was performed by two deflectometers type of 6PAO with division of a scale 0.01 mm. The first count out right after putting the loading, then consequently 4 counts out with the interval 15 minutes, 2 counts out with the interval 30 minutes and further in every hour till the conditional stabilization of deformation. Figure 14. The scheme of anchor-persistent test bench. 1 FDP pile, 2 basic beam, 3 auxiliary beam, 4 pipes for welded seam, 5 jack, 6 - caving in-measurer, 7 - benchmark system, 8 pump with manometer. Table 6. Results after static load tests piles. Type of pile # of pile Diameter or section (cm) Pile length in soil (m) Maximal load (kn) Settlement (mm) CFA FDP Precast 3 30x CFA Bored Bored Since maximum pile settlements did not run up to the ultimate settlement value being 16 mm, the maximum imposed loads were taken as the pile bearing capacity [Bozozuk 1979, Bartolomey 1994].

7 Load (P), kn boring piles, which performed through casing pipe (Fig. 17) S e ttlement (S), mm Figure 17. Pile Integrity Test (PIT) after installation of piles CFA pile No.1 (17 m) Diameter 600 mm; FDP pile No.2 (17 m) Diameter 410 mm; Driven pile No.3 (12 m) Cross section 300x300 mm; Reloding Reloading Reloading Figure 15. The comparing curves of piles dependences of settlements S from the loading P. Figure 16. The comparing curves of piles dependences of settlements S from the loading P. 4.3 Pile Integrity Test (PIT) The results of PIT (FPDS 1999) show that the quality of body of boring piles, which performed through technology of CFA better than quality of bodies of precast piles and 5 CONCLUSIONS 1. CFA pile technology is more effective and has advantages in comparing of other piles: higher bearing capacity; economic efficiency; high production rates; ecologically harmless (no noise and no vibration); handy by manufacture and at transportation etc. 2. The advantages of the FDP pile techniques are: high productivity and bearing capacity of the FD piles; high quality of filling of a borehole concrete under pressure; absence of a sludge by boring of a ground on a construction site. 3. Soil condition of Astana has various type of dense soil, and hard soil bands, which it is impossible to use soil grounds of pile foundations of buildings, like these types of soil precast piles breaking in soil at driving time or breaking head of pile and bearing capacity is not high. With steel H-piles can drive dense soils, hard soil bands and can drive until rock soils and bearing capacity rather high. Steel H - pile has advantage, can be driven very long lengths by using any type of extension method (welding, bolting splice).

8 REFERENCES ASTM A572/A572M Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel. ASTM D Standard Test Method for Piles Under Static Axial Compressive Load. Bazilov, R. Analysis Steel Pile with H-beam section on Soil Grounds of Astana. 3 rd International Young Geotechnical Engineer Conference, th of September, 2005, Osaka, Japan, 35 p. Bartolomey, A.A., Omelchak, I.M. & Yushkov, B.S Prognosis of settlement of pile foundation. Moscow, 302 p. Bozozuk, M., Keenan, G.H. & Pheeney, P.E Analysis of Load Tests on Instrumented Steel Test Piles in Compressible Silty Soil. Behavior of Deep Foundation, ASTM STP 670. Raymond Lundgren, Ed., American Society for Testing and Materials, pp. FPDS SIT-KIT-B Foundation Pile Diagnostic System Sonic Integrity Testing. Kazakhstan, Temirtau. GOST Soils. Field test methods by piles. М.: Standards Publishing House. SNiP of RK Ground basements and Foundation. Zhussupbekov, A.Zh. & Ashkey, Y Geotechnical Problems of Mega Projects on Difficult soil Ground of Kazakhstan. (The Proceeding of the International Geotechnical Simposium Geotechnical Engineering for Disaster Prevention & Reduction ). Russia, Yuzhno-Sakhalinsk, th of Yuly 2007, pp. Zhussupbekov, A., Bazilov, R. & Bazarbaev, D Interaction of piles with problematical soils of new capital Astana. (Proceedings of the International Geotechnical Conference Development of Urban Areas and Geotechnical Engineering ). Russia, Saint Petersburg, June 2008, pp.