GEOTECHNICAL CHARACTERIZATION OF THE ANTALYA KARSTIC ROCK MASSES

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Erica Richard
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1 GEOTECHNICAL CHARACTERIZATION OF THE ANTALYA KARSTIC ROCK MASSES Dr. Evrim Sopacı Consulting Engineer/Temelsu

2 T U R K E Y The city of Antalya is built on and surrounded by one of the largest (600 km 2 ) and thickest (up to 250 m) deposits of tufa (i.e. calcium carbonate precipitated from cool-water springs) in the Mediterranean region, or elsewhere. Tufa, rather than the more traditional travertine, which is reserved for hotspring deposits (>20C), derives from Tophus, originally used by Pliny to describe a porous rock. 2

3 Geotechnical Characterization of the Antalya Karstic Rock Masses 3

4 Why is Tufa significant in the field of engineering geology? missing geotechnical database unknown controlling parameters of the strength and the deformability characteristics of the Antalya tufa rocks an engineering classification pertaining to the Antalya tufa rocks is missing in the literature the engineering classification to produce rock specific design parameters (i.e., shear strength parameters, deformation modulus, etc.). 4

characteristics of the Antalya tufa rocks an engineering classification pertaining to the Antalya tufa rocks

5 Geotechnical Characterization of the Antalya Karstic Rock Masses b- c- d- e- a- a- PHYTOHERM FRAMESTONE b- MICROCRYSTALLINE c- PHYTOHERM BOUNDSTONE d- INTRACLAST e- PHYTOCLAST 5

6 Geotechnical Characterization of the Antalya Karstic Rock Masses Laboratory and field tests Uniaxial Compressive Strength Test Seismic Refraction Tomography Triaxial Compressive Strength Test Pressuremeter Test Indirect TensileStrength Test Unit weight and Porosity determination 6

$Refraction Tomography Triaxial Compressive Strength Test Pressuremeter$

7 Results of Lab Tests of the Antalya tufa rock types Uniaxial compressive strength test Brazilian tensile strength test Tufa types σ c (MPa) E (GPa) ν σ t (MPa) No. of Std. Mean Mean Std. Mean Std. No. of Std. Mean sample dev. dev. dev. sample dev. Microcrystalline Intraclast tufa Phytoherm framestone Tufa type Porosity (%) Unit weight (kn/m 3 ) Mean Std. Dev. Mean Std. Dev. Microcrystalline tufa Phytoherm framestone Intraclast tufa

66 1.34 1.54 0.61 0.29 0.23 - - - Phytoherm framestone 13 7.76 5.35 4.41 2.99 0.11 0.05 9 1.40 0.80 Tufa type Porosity (%) Unit weight (kn/m 3 ) Mean Std.

8 Results of Lab Tests of the Antalya tufa rock types P-wave velocity (m/s) S-wave velocity (m/s) To (s) Type / Parameters Mean ± St.d. Mean ± St.d. Mean ± St.d. Intraclast 1836 ± ± ± 0.09 Phytoherm framestone 2350 ± ± ± 0.02 Microcrystalline tufa 2299 ± ± ± 0.04 Tufa type c (MPa) φ ( ) m i Mean Std. Dev. Mean Std. Dev. Mean Std. Dev. Microcrystalline tufa Phytoherm framestone Phytoclast

02 Microcrystalline tufa 2299 ± 437 1234 ± 311 0.21 ± 0.04 Tufa type c (MPa) φ ( ) m i Mean Std. Dev. Mean Std. Dev. Mean Std. Dev. Microcrystalline tufa 3.

9 Results of Lab Tests of the Antalya tufa rock types Borehole Location Depth (m) Lithology PL (kpa) PLn (kpa) E (MPa) BH-4 Lara BH-4 Lara BH-4 Lara 13.0 Intraclast tufa BH-7 Lara BH-8 Konyaaltı BH-2 Lara BH-2 Lara BH-3 Lara 2.50 Phytoherm framestone BH-3 Lara BH-6 Lara Mean ± one standard deviation Intraclast tufa 1565 ± ± ± 39.6 Phytoherm framestone 1878 ± ± ±

6 BH-2 Lara 3.50 1569 1215 12.3 BH-2 Lara 9.50 2000 2000 95.3 BH-3 Lara 2.50 Phytoherm framestone 2000 2000 86.4 BH-3 Lara 6.00 1765 1411 14.

10 Controlling parameters In regards to the factor(s) controlling the Antalya tufa rock strength or behavior, porosity has been observed to be the most probable candidate responsible for the variations Analyzing the regression results of the geomechanical parameters, it seems that the Antalya tufa rock may be better characterized by using strength parameters, namely, uniaxial compressive and tensile strength, together with index parameters such as unit weight 10

of the geomechanical parameters, it seems that the Antalya tufa rock may be better characterized by using strength

11 GSI 75 ± 5 40 ± 5 30 ± 5 20 ± 5 20 ± 5 Microcrystalline tufa Phyotherm framestone Phyotherm boundstone Phytoclast tufa/intraclast tufa 11

12 Rock Mass Parameters Microcrystalline tufa Phytoherm framestone Phytoclast tufa Intact rock strength (MPa) Hoek-Brown constant, mi Geological Strength Index 75±5 40±5 20±5 Intact rock modulus, Ei (GPa) Hoek-Brown constant, mb Hoek-Brown constant, s Constant, a Deformation modulus (GPa) Mohr-Coulomb fit c (MPa) φ ( )

41 2.26 Hoek-Brown constant, mb 6.142 0.704 0.517 Hoek-Brown constant, s 0.0622 0.0013 0.0001 Constant, a 0.501 0.

13 Thank you... 13

Numerical analysis of boundary conditions to tunnels

Global journal of multidisciplinary and applied sciences Available online at www.gjmas.com 2015 GJMAS Journal-2015-3-2/37-41 ISSN 2313-6685 2015 GJMAS Numerical analysis of boundary conditions to tunnels