Excavation Techniques - Group 4 PDF

GROUP 4  EXCAVATION WHAT IS EXCAVATION? refers to the process of removing soil or rock from a specific area. It's essentially digging, but on a larger scale and often for a specific purpose. COMMON APPLICATION OF EXCAVATION 1. CONSTRUCTION This is the most frequent us...

GROUP 4  EXCAVATION WHAT IS EXCAVATION? refers to the process of removing soil or rock from a specific area. It's essentially digging, but on a larger scale and often for a specific purpose. COMMON APPLICATION OF EXCAVATION 1. CONSTRUCTION This is the most frequent use. Excavation is needed to create foundations for buildings, roads, and other structures. It also involves digging trenches for underground utilities like pipes and cables. 2. ARCHEOLOGY Unearthing artifacts and fossils buried underground requires careful excavation techniques. Archaeologists meticulously remove soil layer by layer to learn about past societies. 3. MINING Extracting minerals, ores, and precious stones from the earth involves large-scale excavation methods. This can be done through surface mines or underground tunnels.  SAFETY PRECAUTIONS Before You Dig: Underground Utility Locating: This is crucial! Identify and mark the location of underground utilities (pipes, cables) to avoid striking them during excavation. Contact a professional locating service or your local utility companies. Planning and Permitting: Obtain any necessary permits and have a proper plan in place. This should include the excavation depth, soil analysis (stability assessment), and shoring requirements. Site Assessment: Inspect the area for potential hazards like overhead power lines, unstable slopes, or presence of hazardous materials. During Excavation: Protective Equipment: Everyone on site should wear appropriate personal protective equipment (PPE) like hard hats, high-visibility vests, steel-toed boots, and eye protection. Respiratory protection might be needed in dusty environments. Safe Access and Egress: Ensure safe entry and exit points for workers in trenches or excavations. This could involve ladders or ramps with proper railings. Shoring and Support: For deeper excavations or unstable soil conditions, use proper shoring systems (supports) like trench boxes, sheet piling, or sloping to prevent cave-ins. Spoil Placement: Keep excavated material at least 2 feet from the edge of the excavation to prevent pressure buildup and potential collapse. Weather Monitoring: Be mindful of weather conditions. Heavy rain or storms can loosen soil and increase the risk of cave-ins. Stop work if necessary. Competent Person: Have a designated competent person on site who is knowledgeable about excavation safety standards and can identify and address hazards.  TYPES OF EXCAVATION Trench Excavation: Relatively narrow and deep ditches dug for laying underground pipes, cables, or installing foundations are called trenches. Trenching requires careful shoring to prevent cave-ins, especially for deep trenches. https://youtu.be/zI0wWcnogYc?si=ED3Q8Dvc1eMM7zPd Dredging: This specialized excavation method is used to remove underwater material from lakes, rivers, or harbors. Dredging is often used to maintain waterways, deepen ports, or for environmental remediation projects. https://youtu.be/Ho427Fixap8?si=jARB-Ds-XrT0S47r Slope Excavation:Creating inclined surfaces for roads, embankments, or retaining walls often involves slope excavation. The angle of the slope depends on the soil stability and engineering requirements. https://youtu.be/uvRFqRxJ7yk?si=Wv6qWT-Hs6qisihb  BASIC COMPUTATION OF EXCAVATION How to calculate excavation costs? To calculate excavation costs, multiply the excavated zone's length, width, and depth to estimate its volume. To obtain the cost of excavation, multiply the total excavation volume by the price of the area per unit. For example :- If an excavated area has a length of 12m and a width of 5m, and a height of 5m Volume = 12 x 5 x 5 = 300 If the price per unit is $8, then the total price will be; TOTAL PRICE = 300 x 8 =$2400  ADVANTAGE OF EXCAVATION Construction Foundations: Buildings, roads, and bridges all require stable bases. Excavation removes soil or rock to create a solid foundation for safe and long-lasting structures. Underground Utilities: Trenches dug through excavation allow for the installation and maintenance of essential utilities like water pipes, sewage systems, electrical cables, and communication lines. Site Preparation: Excavation helps level uneven terrain, create basements, and prepare land for construction projects.  DISADVANTAGE OF EXCAVATION Environmental Impact Soil Erosion: Excavation can expose soil to wind and water, leading to erosion and sedimentation in nearby waterways. Habitat Disruption: Removing soil and vegetation disrupts ecosystems and can harm wildlife habitats. Air and Noise Pollution: Excavation activities can generate dust and noise pollution, impacting air quality and disturbing surrounding areas.  DISADVANTAGE OF EXCAVATION Cost and Time Equipment and Labor: Excavation projects require specialized equipment and trained personnel, leading to significant costs. Project Delays: Unexpected conditions like encountering rock formations can cause delays in excavation schedules. Safety Concerns Cave-ins: Unstable excavations can collapse, posing a serious danger to workers. Falling Objects: Debris or loose materials could fall from excavation walls, injuring workers or bystanders. Exposure to Hazardous Materials: Excavation might expose workers to buried hazardous materials like asbestos or lead.  TOOLS AND EQUIPMENTS Heavy Machinery (Large-scale excavations) Excavators: These versatile machines Bulldozers:Powerful tracked have a digging arm with a bucket for vehicles with a large blade at scooping, loading, and trenching. the front for pushing large They come in various sizes and amounts of soil, clearing land, configurations (tracked or wheeled, and creating berms. different boom lengths). Loaders: Similar to bulldozers but Backhoes: Essentially an excavator with a bucket at the front for with the digging arm mounted on scooping and loading loose the rear, ideal for digging trenches material onto trucks. and basements. Graders:These machines have a Dump Trucks: Used to haul long blade for leveling large areas, excavated soil and debris from the grading slopes, and spreading soil. excavation site. Trenchers: Chain- or wheel-trencher Dredges: Floating excavators used machines specifically designed for for underwater excavation in lakes, efficient trench excavation, often rivers, or harbors. used for laying pipes or cables. Surveying Equipment: Levels, Safety Gear: Hard hats, steel-toed transits, and GPS units are used boots, high-visibility vests, respirators for accurate measurement, site (for dusty environments) are essential layout, and maintaining grade for worker safety. control during excavation.  SHORING AND BRACING Types of Shoring Sheet Piling:Steel sheets driven into Soldier Piles and Lagging:Vertical beams the ground act as a continuous wall to (soldier piles) are driven into the ground retain soil and groundwater. They are with wooden planks (lagging) placed suitable for deep excavations and can horizontally between them, creating a be left in place permanently in some confined space for excavation. cases.  Types of Bracing SLurry Walls: These are diaphragm walls Struts: These are horizontal beams constructed using a bentonite slurry to placed between opposing shoring stabilize the trench face. They are often walls to resist inward pressure. used for deep excavations in soft or wet They can be made of wood, steel, soils. or aluminum. Walers: Horizontal wooden or metal Tiebacks: These are high-strength cables beams attached to the soldier piles or rods anchored deep into the ground or sheet piles to which the struts are behind the excavation. They tie back the connected for added stability. shoring wall, creating a pulling force to counteract the outward pressure of the soil.