Characteristics of Tlemcen’s Clay

 

Bekkouche Abdelmalek

Department. of Civil Engineering, University of Tlemcen, Algeria
e-mail: a_bekkouche@hotmail.com

and

Aissa Mamoune Sidi Mohammed

Department. of Civil Engineering, University of Tlemcen, Algeria
e-mail: aissa_mamoune@hotmail.com

ABSTRACT

Numerous cases of structural damage have been observed in the area as well as in the neighborhood of Tlemcen (North-West part of Algeria) and are regarded as a consequence or our less knowledge of the subsurface soil. Whereas some destroyed facilities have been lost other was restored with in turn lost of billion of Dinars (Algerian currency).

In order to identify the main cause of these damages a geotechnical survey has been conducted in the area of Tlemcen. Hence many soil investigations have been performed and the location of the holes was defined such as these will be close to the damaged structure. Through this soil investigation the soil profile of Tlemcen is now well understood. A geological map of Tlemcen has been established using a 1/2.000.000 scale. Many laboratories test such as physic and chemical identification process, compressibility test, swelling test following numerous standards, and shear test using Casagrande procedure have been conducted. The results of these laboratories test combined with geological map have been useful to establish a detailed geotechnical map of Tlemcen. This map is undoubtedly of great importance for urbanisms to avoid past errors. Indeed, this map highlights great heterogeneity of Tlemcen’s soil with emphasis on rock and clay soil on which many facilities have been built. For rock soil, no problem is expected in terms of soil bearing capacity but additional money is necessary for dewatering. On the other hand for clay soil, swelling phenomena could cause severe damages to structures due to unstable level of moisture. This instability is mainly due to drought which has been observed during many years in Tlemcen. This situation was unfortunately not undertaken by previous survey for some new parts of the town. Based on the availability of soils samples some statistical models are proposed to make prevision about the soil behavior. These models allow rapid evaluation of the amplitude and strength of swelling and could serve as a guideline for next implementations of structures.

Computational models and experimental results are presented in this paper.

Keywords: Keywords: finite element method; permeability; soil-water; unsaturated soil.

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