Author: İbrahim ÇOBANOĞLU, Şaziye BOZDAĞ
Publishing Date: 2007
Volume 22 Issue 3
Alluvium in the Adana residential area, over which some of the oldest settlements of the city have developed, is the soil that suffered the most severe structural damages in the 1998 Ceyhan earthquake. These units are spread along the east-west direction at both banks of the Seyhan river and are in contact with the terrace units in the east of the same river. They also contact the terrace and caliche deposits in the west of the Seyhan river. Most of the alluvium deposits in the study area are fine-grained soils. Classification tests that were performed on the samples obtained from surface excavations have revealed that the majority of alluvium deposits are high plasiticty clay (CH) and low plasticity clay (CL). They show characteristics of flood plain sediments. On the other hand, poor graded sand (SW), clayey sand (SC), silty sand (SM) ile poor graded gravel (GP), silty gravel (GM) ve clayey gravel (GC) types of coarse-grained sediments have been observed. Caliche formation effect is typical in alluvium clays. It has been found out that the unit weight values range between 16 and 22 kN/m3 whereas porosity varies between 21 and 47 percent. Liquid limit has been found as fluctuating between 22 and 79 percent, and plastic limit between 13 and 33 percent. Pre-consolidation pressures fluctuate between 130 and 164 kPafor CH and CL types of clays. The compression and swelling indices vary from 0.048 to 0.085 and from 0.0025 to 0.0083 respectively. The physical and mechanical properties obtained on the samples from geotechnical boreholes and trial pits were stored on a geographical base prepared with Arcview Geographical Information System. A data base containing the geotechnical parameters was thereby constituted. The geographical base includes 6 topographical maps of 1/25.000 scale. Using all data, equal SPT-N, resistivity, soil amplification, shear wave velocity and bearing capacity maps were prepared for the study area.
Key Words: Adana; Alluvium; Geotechnical Properties; Geographical Information System