PowerPoint Presentation: Earthwork and Ground Technology Site Improvement PowerPoint Presentation: Methods of site improvement •Removal and replacement •Grouting •Stabilization using admixtures Reinforcement PowerPoint Presentation: Removal and replacement • One of oldest and simplest methods is simply to remove and replace the soil •Soils that will have to be replaced include contaminated soils or organic soils •Method is usually practical only above the groundwater table PowerPoint Presentation: Grouting • Defined as the injection of a special liquid or slurry material called grout into the ground for the purpose of improving the soil or rock •Types of grouts - Cementitious grouts -Chemical grouts PowerPoint Presentation: Grouting methods Intrusion grouting Consists of filling joints or fractures with grout Primary benefit is reduction in hydraulic conductivity Used to prepare foundation and abutments for dams Usually done using cementitious grouts PowerPoint Presentation: Permeation grouting Injection of thin grouts into the soil Once the soil cures, becomes a solid mass Done using chemical grouts Used for creating groundwater barriers or preparign ground before tunneling Grouting methods PowerPoint Presentation: Grouting methods Compaction grouting When low-slump compaction grout is injected into granular soils, grout bulbs are formed that displace and densify the surrounding loose soils. Used to repair structures that have excessive settlement PowerPoint Presentation: Grouting methods Jet grouting Developed in Japan Uses a special pipe with horizontal jets that inject grout into the ground at high pressures Jet grouting is an erosion/replacement system that creates an engineered, in situ soil/cement product known as Soil cretesm . Effective across the widest range of soil types, and capable of being performed around subsurface obstructions and in confined spaces, jet grouting is a versatile and valuable tool for soft soil stabilization, underpinning, excavation support and groundwater control PowerPoint Presentation: Stabilization using admixtures The soil stabilization means the improvement of stability or bearing power of the soil by the use of controlled compaction, proportioning and/or the addition of suitable admixture or stabilizers Types of soil stabilization: Cement stabilization Bituminous stabilization Types of soil stabilization Cement stabilization: C ement stabilization Bituminous stabilization : Bituminous stabilization PowerPoint Presentation: Cement stabilization Admixture used is portland cement. It gives good degree of stabilization. This is used for all types of soils except clayey soil. Bituminous materials like asphalt is used. It increases soil impermeability. This is used for dry soil. Bituminous stabilization PowerPoint Presentation: Reinforcement • Soil is stronger in compression than in tension •To improve strength in tension, geosynthetics placed in soil for soil reinforcement PowerPoint Presentation: Reinforcement Thank you!: Thank you!