Stabilization of cemented collapsing-swelling clay

الملخص EN

Soil stabilization is sometimes considered the best solution to overcome unfavorable properties in the foundation soil.

The target of stabilization is to improve one character or more that affects the behavior of foundation and hence the structure can be exposed to failure.

The most challenge character that always disturbs the engineer is the sensitivity of unsaturated soil to water and its volume change under immersion conditions.

Collapsing and swelling soils are considered the most famous in between the unsaturated problematic soil and although they were exposed to numerous investigations and researches they are still problematic soils. Hamm am, A.H et all, 2007, published a research about some properties of cemented collapsing-swelling clay that has been found in Al-Madinah Al-Munawarah, Saudi Arabia.

This type of unsaturated soil was the main reason to demolish a new building due to the excessive differential settlement and in turn excessive inclination.

After demolishing the building, it was decided to stabilize the site soil with lime additive.

Lab program was designed to carry out Atterberg limits, free swell, modified proctor, unconfined compressive strength and consolidation tests.

The ratio of lime was chosen to be 8 % by weight of dry soil.

Comprehensive comparison was achieved between lab tests of un-treated and lime-treated soils to conclude the soil improvement and to support field stabilization which was executed by deep grouting method. Samples were extracted by drilling boreholes after field grouting and the above lab tests were carried out again to compare between the characteristics of lab lime-treated and field lime treated soils.

The results indicated that cemented collapsing-swelling clay has been significantly improved by lime additive and it changed to water-stable soil.