Under the Guidance of Prof. Jayashree Sengupta SOIL STABILIZATION Presented By - Argha Nag Under the Guidance of Prof. Jayashree Sengupta Department of civil engineering Sir J. C. Bose school of engineering Supreme knowledge foundation group of institutions

WHAT IS SOIL STABILIZATION ??? Improving the engineering properties of soil used for pavement base courses , sub-base courses and sub-grades use the additives which are mixed into the soil to effect the desired improvement.

CLASSIFICATION Cement stabilization Lime stabilization Chemical stabilization Fly-Ash stabilisation Bituminous stabilization Grouting concrete stabilization Geotextile stabilization Reinforced earth stabilization.

PURPOSE OF SOIL STABILISATION Soil stabilization is used to reduce the permeability and compressibility of the soil mass in earth structures and to increase its shear strength. It is used to increase the bearing capacity of foundation soils. It is used to improve the natural soils for the construction of highway and airfields. It is also used to make an area trafficable within a short period of time for emergency purposes. Soil stabilization is used to increase the unit weight of the soil. It helps to decrease the void ratio of the soil. Stabilization of soil increases the shear strength of soil.

Cement stabilization

Pulverised Soil Portland Cement Water Cement stabilization is done while the compaction process is continuing. During the compaction process we use some amount of cement. Some void space can be found in soil particle. Cement is just like paw, so cement can fill the void space of soil easily. As a result, void ratio of soil may reduce. After this primary tasks, when we add water in the compaction the cement reacts with water and become hard. So unit weight of soil is also may increased. Because of the hardening of cement, shear strength and bearing capacity will be increased. Because of the stabilization, permeability of soil may decrease.

FACTORS RESPONSIBLE During soil cement stabilization the following factors are affecting. Type of soil: Cement stabilization may be applied in fine or granular soil, however granular is preferable for cement stabilization. Quantity of cement: A large amount of cement is needed for cement stabilization. Quantity of water: Adequate water is needed for the stabilization. Mixing, compaction and curing: Adequate mixing, compaction and curing is needed for cement stabilization. Admixtures: Cement has some important admixtures itself which helps them to create a proper bond. These admixtures pay a vital role in case of reaction between cement and water.

PROS AND CONS ADVANTAGES DISADVANTAGES It is widely available. Cost is relatively low. It is highly durable. Soil cement is quite weather resistant and strong. Granular soils with sufficient fines are ideally suited for cement stabilization as it requires least amount of cement. Soil cement reduces the swelling characteristics of the soil. It is commonly used for stabilizing sandy and other low plasticity soils. Cement interacts with the silt and clay fractions and reduces their affinity for water. Cracks may form in soil cement. It is harmful for environment. It requires extra labor. The quantity of water must be sufficient for hydration of cement and making the mixture workable.

CONSTRUCTION OF SOIL-CEMENT BASE COURSE Materials The soils to be stabilized, either from the site or from near-by borrow pits are collected. Passing 4.75 mm sieve Passing 0.075 mm sieve Liquid limit plasticity index >50% <50% <40% <18%

ADVANTAGES Slope failures Bridge failures Structural failures These above failures can be eliminated by SOIL STABILIZATION METHOD