Journal of Engineering Geology

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One way of reduction of leakage from beneath of earth dams is using of one contact clay layer with very low permeability and intermediate to high plastisity and connectig it to core of dam. Since, most of fine-grained soil in environtment of dam have low plastisity and preparing it from another place is not economic, use of bentonite in order to improvement of engineering characteristic of borrowed clay is suitable way.
In this search effect of bentonite on geotechnical properties of fine-grained soils with low plastisity are evaluated. Results of this research show that hydraulic conductivity, consolidation coefficient, dry density, colifornia bearing ratio (CBR),.....are decreased with increase in bentonite content but optimum moisture , Aterberg limits , cohession and so on are increased with bentonite addition. Finally, with analysis of obtained result, optimum percent of bentonite is offered in order to improve of engineering properties of used clay in contact region.

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The Dynamic Probing is an important test in site investigation and geotechnical studies. It is used for determination of situation and specification of soil layers when the depth of exploration is moderate. In our country, in the last few years test has been widely used to replace the standard penetration. In this paper, the experiences to use different various types of dynamic probing rigs and the errors that can occur in these experiments are discussed. Then the accuracy of this test is studied to evaluate the specification of fine-grained soils. The most important innovation of this research is the proposition of the new correlations between cone dynamic resistance and undrained shear strength and so compaction percentage in fine-grained soils. The paper encourages the wider application and further development of this test for site investigation in fine-grained soils.

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Kerman city and its surrounding towns in terms of morphology, consist of a flat alluvial plain of fine silt and clay materials. These sediments have very gentle slope, and constitute the city's main infrastructure. Natural soils generally are structured by passing times due to the influence of environmental factors. Geological factors in Kerman alluviums have caused fine structure after deposition. This paper studies briefly sedimentary basin Kerman, mineralogical and geotechnical properties of the sediments of these areas.semi-qualitative analysis of samples has shown that the mineral deposits in Kerman are mainly illite, chlorite, smectite and calcite. then In order to evaluate the effect of depositional environments and geological history of the engineering properties of the sediments of the Kerman city, A large number of triaxial tests on reconstituted soil moisture greater than LL and different confining pressures, consolidated drained and consolidated undrained is done . In order to evaluate the applicability of soil behavior in normal conditions and the reconstructed curves and stress - strain sensitive soils and soil structure compared with standard sensitivity and then their resistance have been investigated. The results of triaxial tests can be used to interpret the depositional environments and geological history. Comparing the curves of stress - strain in natural and reconstituted samples indicates that in many cases the behavior of intact and reconstituted soils were similar and cementation and soil structure have not been much development. Also Comparison of electron microscopy images of reconstituted and intact samples, not random arrangement of particular structure and soil compaction within the city limits have confirmed. therefore, soils of Kerman are relatively similar by the influence of depositional environments and geological history. these soils have a lot of structure and cementation and are generally compact and strengthening.