1. EFFECT OF CLAY STRUCTURE ON ITS MECHANICAL BEHAVIOR INCLODING COSOLIDATION AND SHEAR STRENGTH By: Moemen Shaban Abd Elwhaab Mohamed Presented To: Dr. Ehab Helmy 2019

2. 1- Introduction  Structure of clay changes from one soil to another, Nature and arrangement of atoms in the mineral have a significant influence on soil behavior: chemical, physical, and surface activity. Surface activity is the ability of particles to attract and repel other particles, which depends mainly on: Mineral, Specific Surface and Crystal form.  So we should study the behavior of clay minerals according to their structure specially shear strength and consolidation 2019

3. 2- Literature Review  In the past years, the need of strengthening of clay mineralogy increased dramatically to overcome problems such as failure in soft clay soil and swelling soil, bearing capacity failure, etc. Several materials and strengthening methods have been introduced, but the research for perfect material and method is still ongoing. 2019

4. 3- Methodology  In order to accurately represent the soil in finite element programs, the analysis must be nonlinear and the elements in PLAXIS 3D were selected to represent that behavior of clay. Some important experiments on soft clay and swelling clay samples must be performed in soil mechanics lap. 1-Consolidation test. 2-Triaxial compression test. 3-compaction tests. 2019

5. 4- Analysis and Discussion  Different combinations of tetrahedral and octahedral sheets form different clay crystals.  Collapsible soils are known to withstand high normal stresses without undergoing a significant volume change in an air-dry state. The soil is, however, susceptible to a large volume change upon wetting. The volumetric collapse behavior of these soils is of great engineering interest to address the problem of ground subsidence. 2019

6. 4- Analysis and Discussion 2019

7. 4- Analysis and Discussion 2019

8. 4- Analysis and Discussion 2019

9. 5-References 1)ECP Committee 203, "The Egyptian Code for Soil Mechanics and Foundations", Part3 and Part4. 2) ASTM D2435-03. 2)ASTM. 2007b. Standard test method for pH of soils. ASTM standard D4972 American Society for Testing and Materials, Philadelphia, 3)Terzaghi, K. 1925, “Principal of Soil Mechanics-III” Eng. News Record, Vol. 95, PP.832 4)ASTM D698 – 00a  1 and ASTM D 1557 – 02  1 5)AASHTO T99-70 (Standard) and T180-70 (Modified) 6)Ch. 4_AA Holtz & Kovacs - An Introduction to Geotechnical Engineering. 7)ASTM. 2007a. Standard test method for particle-size analysis of soils. ASTM standard D422. American Society for Testing and Materials, Philadelphia, Pa. Google Scholar 2019