Engineering Geology PDF

ENGINEERING GEOLOGY WEEK 5 to WEEK 8 Classroom Rules: 1. Respect Everyone 2. No bullying 3. Listen Carefully 4. Raise your Hand to Talk 5. Be Punctual 6. No gadgets during Discussion 7. Phones must be in silent mode TENTATIVE SCHEDULE Prelim Exam - September 1st...

ENGINEERING GEOLOGY WEEK 5 to WEEK 8 Classroom Rules: 1. Respect Everyone 2. No bullying 3. Listen Carefully 4. Raise your Hand to Talk 5. Be Punctual 6. No gadgets during Discussion 7. Phones must be in silent mode TENTATIVE SCHEDULE Prelim Exam - September 1st week Midterm Exam - October 15/16 week Prefinal Exam - November 12/13 Final Exam - December 10/11 GRADE CALCULATION COURSE OUTLINE 1. General Geology 2. Petrology 3. Mineralogy 4. Structural Geology and Rock Mechanics 5. Geological and geophysical Investigation in Civil Engineering 6. Energy sources GEOLOGY as geoscience or earth science, Geology is the primary Earth science and looks at how the earth formed, its structure and composition, and the types of processes acting on it. Geology is concerned with the history of the earth over the course of its 4.5 billion year life. By studying the structures of the earth we can unlock its hidden past and anticipate its future. ENGINEERING GEOLOGY  A scientific study of geology as it relates to civil engineering projects such as the design of a bridge, construction of a dam or preventing a landslide. Last week we learned: Earthquake Continental Drift Plate Techtonics Geology Engineering Geology Instruments use for Earthquake EARTH - is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land PETROLOGY Is the branch of geology concerned with the compositions, structures, and origins of rocks. Petrography  really a subdiscipline of petrology, deals specifically with the description and classification of rocks.  Most petrologic research involves petrography, typically involving examination of rocks in outcrop and hand sample, but often most importantly by examining rocks at high magnification. What is Micron? A micron is one-millionth of a meter or one unit of length. One micron is equivalent to one μm, or 10-6 meters. The smallest object sizes are expressed in microns or micrometers Things as small as one micron in diameter can only be seen with a microscope or other form of magnification; items as thick as ten microns are hardly visible at all. A human hair’s diameter ranges from 70 microns to 210 microns, depending on the individual’s hair thickness. 30 microns is equal to exactly 0.03 millimeters. MEASURING TINY LINEAR MEASUREMENT Micrometer is an instrument used for making precise linear measurements of dimensions such as diameter, thickness, and lengths of solid bodies. Micrometer is also known as a micrometer caliper. Vernier Caliper a linear measuring instrument consisting of a scaled rule with a projecting arm at one end, to which is attached a sliding vernier with a projecting arm that forms a jaw with the other projecting arm.. IMPORTANCE OF PETROLOGY IN CIVIL ENGINEERING 1. It provides an opportunity to interpret the physical properties of individual rocks, likewise: texture, structure, mineral composition, chemical composition etc. 2. This helps in knowing the strength, durability, colour, appearance, workability etc. Concrete  a hard strong building material made by mixing a cementing material (such as Portland cement) and a mineral aggregate (such as sand and gravel) with sufficient water to cause the cement to set and bind the entire mass or calcium oxide (CaO), is derived from high quality natural deposits of limestone, or Cement LIME calcium carbonate (CaCO3). Limestone is a sedimentary rock that formed millions of years ago as the result of the accumulation of shell, coral, algal, and other ocean debris. Silicon dioxide, also known as silica, is an oxide of silicon with the SILICA chemical formula SiO 2, commonly found in nature as quartz Gravel  (also known as crushed stone) is a collection of loose material that’s primarily made of rock fragments. The most common types of rock found in gravel are basalt, limestone, and sandstone Sand  when rocks break down from weathering and eroding over thousands and even millions of years waste materials from these devices are especially problematic, as they contain harmful chemicals, heavy metals, and numerous toxins which can cause environmental damage and health risks for communities living near landfill sites. Furthermore, sending e-waste to landfill means that valuable resources contained in devices are lost. This innovative solution could help to reduce the environmental impact of both the electronics and the construction industries. Valorizing e-waste for this key application reduces the carbon footprint of cement production and reduces e-waste, a critical issue in the electronics industry. Coco Board Rock is a solid aggregate of mineral materials A relatively hard, naturally occurring mineral material. Rock can consist of a single mineral or of several minerals that are either tightly compacted or held together by a cementlike mineral matrix ROCKS TYPES: 1. Igneous rock are “fire-born,” meaning that they are formed from the cooling and solidification of molten (melted) rock. The word igneous derives from ignis, the Latin word for “fire.” Since their constituent minerals are crystallized from molten material, igneous rocks are formed at high temperatures. They originate from processes deep within the Earth— typically at depths of about 50 to 200 kilometres (30 to 120 miles)—in the mid- to lower- crust or in the upper mantle. Igneous rocks are subdivided into two categories: 1. Intrusive Igneous rock / Plutonic Rocks formed from magma forced into older rocks at depths within the Earth’s crust, which then slowly solidifies below the Earth’s surface, though it may later be exposed by erosion 2. Extrusive Igneous rock / Volcanic Rocks are rocks formed from lava erupted from a volcano. Volcanic rocks are among the most common rock types on Earth's surface, particularly in the oceans. On land, they are very common at plate boundaries and in flood basalt provinces. It has been estimated that volcanic rocks cover about 8% of the Earth's current land surface Examples of Igneous Rocks Extrusive Rocks / volcanic andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff. Intrusive Rocks / plutonic diabase, diorite, gabbro, granite, pegmatite, and peridotite. 2. Sedimentary rock Are formed through the accumulation and compaction of sedimentary materials such as minerals, organic matter, and debris often in layers over a long periods of time. rock formed at or near Earth’s surface by the accumulation and lithification of sediment (detrital rock) or by the precipitation from solution at normal surface temperatures (chemical rock). Sedimentary rocks are the most common rocks exposed on Earth’s surface but are only a minor constituent of the entire crust, which is dominated by igneous and metamorphic rocks. Sedimentary rocks are subdivided into two categories: Organic Sedimentary rock is form from the accumulation and lithification of organic debris, such as leaves, roots, and other plant or animal material Clastic sedimentary rock are formed from broken up pieces of other rocks, not from living things. Chemical Sedimentary rock produced from the dissolution and precipitation of minerals. 3. Metamorphic rock Are formed from pre-existing rocks that undergo intense heat, pressure, or chemical process deep within earths crust. are rocks that have become changed by intense heat or pressure while forming. In the very hot and pressured conditions deep inside the Earth’s crust, both sedimentary and igneous rocks can be changed into metamorphic rock. In certain conditions these rocks cool and crystallize usually into bands of crystals. Later they can become exposed on Earth’s surface. (metamorphism) is to consider what happens when soft clay objects are put into a kiln and heated to a very high temperature. They change from being squashy to rock hard. They cannot be changed back to their original form. The material has been changed. This is what happens on a huge scale underground producing metamorphic rock. Foliated Metamorphic Rocks As pressure squeezes on a parent rock during recrystallization it causes the platy or elongated minerals within the rock to become aligned, or foliated. Foliated rocks develop a platy or sheet-like structure that reflects the direction that pressure was applied in. Non-foliated Metamorphic Rocks Not all parent rocks have platy or elongated minerals and when these rocks undergo metamorphism the individual mineral grains do not align. The rock cycle fundamental process that shapes the Earth's surface, creating mountains, valleys, and other landforms. plays a vital role in the formation of soils, the cycling of minerals, and the formation of fossil fuels. essential for comprehending Earth's history, its geological processes, and the resources it provides. Driving Forces of the Rock Cycle 1. Plate Tectonics: The movement of Earth's tectonic plates is a major driving force behind the rock cycle. Plate collisions create mountains, expose rocks to weathering and erosion, and generate magma through subduction. 2. Water Cycle: The water cycle plays a crucial role in weathering and erosion, transporting sediments and dissolving minerals. 3. Earth's Internal Heat: The heat from Earth's core drives magma generation and volcanic activity, which are essential for the formation of igneous rocks.  Earth Processes Earth processes encompass the dynamic and interconnected forces that shape our planet's surface, atmosphere, and interior. These processes can be broadly categorized as exogenic (external) and endogenic (internal), each driven by distinct energy sources and influencing the other. various natural forces and actions that constantly shape and reshape our planet, both on the surface and within its interior. 1.Exogenic Processes: Shaping the Surface occur at the Earth's surface, primarily driven by solar energy and gravity. They are responsible for weathering, erosion, transportation, and deposition of materials, ultimately shaping the landscape. 2. Endogenic Processes: Shaping the Interior originate within the Earth, driven by internal heat and pressure. They are responsible for the formation of mountains, volcanoes, earthquakes, and the movement of tectonic plates. Humus is dark, organic material that forms in soil when plant and animal matter decays is the stable, decomposed organic matter found in soil. It's the result of a long and complex process where dead plant and animal matter is broken down by microorganisms like bacteria and fungi. Processes of Humus 1. Decomposition is the initial stage where microorganisms like bacteria and fungi break down dead plant and animal matter into simpler substances. This process is crucial for releasing nutrients back into the soil, making them available for plants. 2. Humification is the process of transforming partially decomposed organic matter into stable, complex organic compounds, known as humic substances. These substances are resistant to further decomposition and form the core of humus. Benefits of Humus Humus is essential for healthy soil and sustainable agriculture. Its benefits include: 1. Enhanced plant growth: Humus provides nutrients, improves water retention, and promotes root growth, leading to healthier and more productive plants. 2. Improved soil structure: Humus promotes aggregation, improving aeration, drainage, and root penetration. 3. Reduced erosion: Humus helps bind soil particles together, reducing the risk of erosion by wind and water. 4. Increased water infiltration: Humus improves soil structure, allowing rainwater to infiltrate more easily, reducing runoff and improving water retention. 5. Enhanced biodiversity: Humus provides a habitat and food source for beneficial microorganisms, increasing soil biodiversity and promoting ecosystem health. Master Horizons: The Main Layers The most common soil horizons are designated by capital letters: O Horizon (Organic): This is the topmost layer, composed primarily of organic matter like decomposing leaves, twigs, and other plant and animal residues. It's often dark and rich in nutrients. A Horizon (Topsoil): This layer is a mixture of minerals from the parent material and organic matter from the O horizon. It's typically darker than the layers below and is considered the most fertile layer. E Horizon (Eluviated): This layer is often found in older soils and forest soils. It's lighter in color than the A horizon because it has been leached of clay, minerals, and organic matter, leaving behind sand and silt particles. B Horizon (Subsoil): This layer is enriched with minerals and clay that have leached down from the A or E horizons. It's typically denser and less fertile than the topsoil. C Horizon (Parent Material): This layer consists of weathered rock fragments and minerals from the bedrock. It's less affected by soil-forming processes and is the foundation for the upper soil horizons. R Horizon (Bedrock): This is the solid, unweathered rock layer that underlies the soil profile. Weathering  is the process by which rock deteriorates until it eventually breaks down to soil Products of Weathering includes Sand Clay Rock fragments 3 Types of Weathering Physical Weathering or Mechanical Weathering  Physical weathering includes pressure, water and temperature changes  occurs when rock is broken down through mechanical processes such as wind, water, gravity, freeze-thaw cycles, or the growth of roots into rock.  Involve the breakdown of rocks into fragments or their disintegration into smaller pieces without altering the mechanical composition. Chemical Weathering  Chemical weathering includes oxidation, biological action and dissolution (the dissolving of certain kinds of rocks).  The alteration of rocks into new minerals Biological Weathering  The main agent in biological weathering is the organic acids released by organisms such as bacteria, lichens, mosses, and decaying plants of many times. Physical Weathering Chemical Weathering Physical Weathering Subsection includes: Thermal Stresses From the expansion or contraction of rocks, caused by temperature changes. It comprimes main types, thermal shock and thermal fatigue Spheroidal Weathering and Block Disintegration Is the flaking of highly heated, exposesd rock as it expands more than the cooler rock underneath it. Frost Action The process wherein snow or ice inside cracks cause their expansion and the ultimate fragmentation of the rock. Pressure release Also know as ‘unloading’ phenomenon, the overlying rock by erosion or other processes causes the underlying rocks to expand and develop fractures paralledl to the surface. Slacking and Holoclasty Is the process that causes the crumbling of rocks when exposed to air or moisture Hydraulic action When water from powerful waves rushes rapidly into the cracks on the rock face, hydraulic action takes place. Tree root action Can widen the joints and fractures in rocks as they grow up, casuing weakness and ultimately the crumbling of the mass  Water Weathering Freeze-Thaw Weathering THERMAL STRESS Root Weathering Wind Weathering Chemical Weathering  In hot, humid climates the following are the most important processes Decomposition  The result of chemical changes on exposure to the atmposhere (H2O, C02 and O2). Disintegration  Inter and intra grain crack growth and coalescence of cracks to form fissures and propagation of large scale joints Eluviation  The soft, disintegrated (or dissolved) material is washed out from the parent rock fabric through open joints or from porous skeletal structure Chemical Weathering Salt Weathering Salt weathering is where expanding salt crystals break fragments of rock that create an increasingly larger hole over time. The pattern that results is known as honeycomb weathering Decomposition Disintergration Chemical Weathering Subsection includes: is the reaction of rock minerals with oxygen, thus changing the Oxidation mineral composition of the rock. When minerals in rock oxidize, they become less resistant to weathering. Iron, a commonly known mineral, becomes red or rust colored when oxidized. is the process of rock minerals reacting with carbonic acid. Carbonic Carbonation acid is formed when water combines with carbon dioxide. Carbonic acid dissolves or breaks down minerals in the rock is a chemical reaction caused by water. Water changes the chemical composition and size of minerals in rock, making them less resistant to Hydrolysis weathering. Click on the video clip below to see hydrolysis of a relatively weathering resistant mineral, feldspar Weathering Depends on may Factors 1. Tends to be faster in the hot and humid tropics 2. The higher the temperature, the faster is the weathering 3. The more the mineral surface area is exposed in the rock by joints, the faster will be the weathering. 4. Increased number of cracks in the rocks will aloow the agents of water and oxygen to interact more intensely with the minerals 5. The mineral composition of the rock is also a factor of weathering Classification of Weathering Grades Soil the upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles Types of Soil The first type of soil is sand. It consists of small particles of weathered rock. Sandy soils are one of the poorest types of soil for growing plants 1. Sandy Soil because it has very low nutrients and poor water holding capacity, which makes it hard for the plant’s roots to absorb water. This type of soil is very good for the drainage system. Sandy soil is usually formed by the breakdown or fragmentation of rocks like granite, limestone and quartz. which is known to have much smaller particles compared to sandy soil and is made up of rock and other mineral particles, which are smaller 2. Silt Soil than sand and larger than clay. It is the smooth and fine quality of the soil that holds water better than sand. Silt is easily transported by moving currents and it is mainly found near the river, lakes and other water bodies is the smallest particle among the other two types of soil. The particles in this soil are tightly packed together with each other with very 3. Clay Soil little or no airspace. This soil has very good water storage qualities and makes it hard for moisture and air to penetrate into it. It is very sticky to the touch when wet but smooth when dried. Clay is the densest and heaviest type of soil which does not drain well or provide space for plant roots to flourish. is the fourth type of soil. It is a combination of sand, silt and clay such that the beneficial properties of each are included. For instance, it has 4. Loamy Soil the ability to retain moisture and nutrients; hence, it is more suitable for farming. This soil is also referred to as agricultural soil as it includes an equilibrium of all three types of soil materials, being sandy, clay, and silt, and it also happens to have humus. Apart from these, it also has higher calcium and pH levels because of its inorganic origins.  Sandy Soil Silt Soil Clay Soil The particle size of silt ranges from 0.002 and 0.06 mm. lay particles are the finest of all the soil The particle size of course sand ranges particles, measuring fewer than 0.002 from 2 - 4.75mm, Medium sand ranges from 0.425 - 2 mm and fine sand ranges mm in size. from 0.075 - 0.425 mm Loamy Soil pH A measure of how acidic or basic a substance or solution is. pH is measured on a scale of 0 to 14. is a critical factor in determining the health and productivity of plants. It measures the acidity or alkalinity of soil, with a scale ranging from 0 (most acidic) to 14 (most alkaline). A neutral pH is 7. Understanding soil pH is essential for gardeners, farmers, and anyone involved in plant cultivation, as it directly affects the availability of nutrients to plants and the activity of beneficial microorganisms in the soil. Soil pH is a critical factor in plant growth and overall soil health. Understanding the importance of pH, testing soil The way the other particles combine in the soil regularly, and adjusting it when necessary can lead to makes the loam. For instance, a soil that is 30 healthier plants, increased yields, and a more sustainable percent clay, 50 percent sand and 20 percent silt is gardening practice. By paying attention to soil pH, a sandy clay loam, gardeners and farmers can create optimal growing conditions for their plants and contribute to a thriving ecosystem. VOIDS -refers to the spaces or gaps between soil particles. Classification of Soil Residual Soil Soil covering only the top part of the bedrock from which it has been derived Soil deposits are of limited thickness varying roughly between 15m and 60m and prevalent in hell slopes Transported Soil Soil formed of materials transported and deposited may very thick Is a mixture of particles derived from rocks of two or more regions and also of reworked sediments NSCP National Structural Code of the Philippines A guide for structural and civil engineers in designing and assessing buildings and other structures. The NSCP provides a standard set of criteria for structures' design, construction, and upkeep. the purpose of this code is to provide minimum requirements for the design of buildings, towers, and other vertical structures. National Building Code of the Philippines cover the following disciplines: architectural, civil/structural, electrical, mechanical, sanitary, plumbing, and electronics. This shall also apply to the design, location, siting, construction, alteration, repair, conversion, use, occupancy, maintenance, moving, demolition of, and addition to public and private buildings and structures Building Permit is a legal document granting you permission to construct a structure or make improvements to one: The local government issues building permits for commercial and residential construction. Any person, business, or organization wishing to carry out construction work on a specific site must request a building permit from the relevant LGU. This covers individuals that want to build, make changes to, renovate, or destroy a building. Third Party laboratory are independent entities that provide objective assessments of construction quality. Third Party laboratory Backfill Material is the process of filling in the excavated area around a foundation or structure. The backfill material can be anything from soil to gravel and is usually compacted to provide support and stability Liquid Limit (LL) is the moisture content at which a fine-grained soil no longer flows like a liquid Plastic Limit (PL) Is the moisture content at which a fine-grained soil can no longer be remolded without cracking. Plasticity Index defined as the range of moisture contents over which the soil deforms plastically (PI) Soil Boring Soil Boring Test is a crucial investigation process used to analyze the subsurface soil conditions at a construction site or for other engineering projects. It involves drilling holes into the ground to collect soil samples at various depths. These samples are then analyzed to determine the soil's: These samples are then analyzed to determine the soil's: 1. Composition Identifying the types of soil present (e.g., clay, sand, gravel, silt), their layering, and the presence of any problematic materials like expansive clays or rock outcroppings. 2. Strength Assessing the soil's ability to bear weight and support structures, which is crucial for designing foundations. 3.Moisture Content Determining the amount of water present in the soil, which can affect its stability and behavior. 4.Other properties Analyzing factors like density, permeability, and the presence of contaminants. Boring and Load Tests Buildings or structures of three (3) storeys and higher Boring tests and, if necessary, load tests shall be required in accordance with the applicable latest approved provisions of the National Structural Code of the Philippines (NSCP). However, adequate soil exploration (including boring and load tests) shall also be required for lower buildings/structures at areas with potential geological/geotechnical hazards. The written report of the civil/geothecnical engineer including but not limited to the design bearing capacity as well as the result of tests shall be submitted together with the other requirements in the application for a building permit. Boring test or load test shall also be done according to the applicable provisions of the NSCP which set forth requirements governing excavation, grading and earthwork construction, including fills and embankments for any building/structure and for foundation and retaining structures. Why is Soil Boring Important? 1. Foundation Design: The results inform engineers about the best foundation type and depth needed to ensure a safe and stable structure. 2. Construction Planning: The data helps determine the feasibility of building on a particular site, identify potential risks like landslides, and plan for excavation and other construction activities. 3. Environmental Assessment: Soil boring tests can reveal potential contamination, helping assess the environmental impact of a project and ensure compliance with regulations. 4. Mineral Exploration: Soil boring is used to explore for mineral resources, including oil and gas, by analyzing the composition and layering of the soil.  Soil boring tests are a fundamental part of any construction or engineering project that involves interaction with the ground. They provide valuable information about the soil's properties, allowing for informed decisions about foundation design, construction planning, and environmental protection. To determine the soil bearing capacity: 1. Insitu Test 1.1 Standard Penetration Test (SPT): This is a widely used and relatively inexpensive test. A heavy hammer drives a standard sampler into the ground, and the number of blows required to penetrate a specific distance is recorded. This "N-value" provides an indirect indication of soil density and strength, which can be used to estimate bearing capacity. Standard Penetration Test (SPT) is a simple and low-cost testing procedure widely used in geotechnical investigation to determine the relative density and angle of shearing resistance of cohesionless soils and also the strength of stiff cohesive soils. 1.2 Plate Load Test A rigid plate of known size is placed on the ground, and a load is applied incrementally. The settlement of the plate is measured, and the bearing capacity is calculated based on the load that causes the soil to shear. This is a direct measurement of bearing capacity, but it can be time- consuming and expensive. 2. Laboratory Test 2.1 Triaxial Test: A soil sample is subjected to different combinations of confining pressure and axial stress. This test provides a comprehensive understanding of the soil's shear strength and deformation behavior under various loading conditions. 2.2 Direct Shear Test: A soil sample is placed between two shear boxes, and a force is applied horizontally until failure occurs. This test measures the soil's shear strength at a specific angle of inclination, providing information about its resistance to sliding. Necessary Results required for Soil Boring Test Ground bearing pressure (bearing capacity of soil) is important because whenever a load is placed on the ground, such as from a building foundation, a crane or a retaining wall, the ground must have the capacity to support it without excessive settlement or failure. 1. Mechanical Seive Analysis sieve analysis consists of shaking the soil sample through a set of sieves that have progressively smaller openings. The results of mechanical analysis (sieve and hydrometer analyses) are generally presented by semi-logarithmic plots known as particle-size distribution curves The sieve analysis determines the gradation (the distribution of aggregate particles, by size, within a given sample) The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. 2. Atterberg Limit soils are determined with a series of laboratory tests that classify the properties of silt and clay soils at different moisture contents. Geotechnical engineers use Atterberg limits to design foundations for structures and predict the behavior of soils for fills, embankments, and pavements. 3. Moisture Content Test Oven Drying Method is a thermogravimetric method (loss on drying) in which the sample is dried for a defined period of time at constant temperature. The moisture content is determined by weighing the sample before and after drying and determining the difference. 4. Hydrometer Test Measuring the particle size distribution of fine-grained soils like clay and silt is best performed using the soil hydrometer test is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. 5. Consolidation Test Consolidation Test Apparatus is used to determine the rate and magnitude of soil consolidation when the soil is restrained laterally and loaded axially. The Consolidation test is also referred to as Standard Oedometer test or One-dimensional compression test. is the basic experiment to measure the settlement characteristics of a clay layer. The rate of consolidation is governed by a coupling between the hydraulic conductivity and the compressibility of the soil Soil Compaction Site Testing includes field density testing using a nuclear density guage It is used to determine the dry and/or wet density and moisture content of the material being tested. The Field Density is usually compared with a laboratory compaction test of the same material type Nuclear density test is a method used to determine the density of compacted materials, primarily soil and This test utilizes a device called a nuclear density gauge, which employs low-level gamma radiation to measure the wet density, dry density, and moisture content of the material being tested. Alternative Soil Compaction Testing Methods 1. Proctor Tests Standard Proctor Test and Modified Proctor Test are laboratory methods that determine the maximum dry density and optimum moisture content of a soil sample. These tests are essential for establishing a benchmark for field compaction control. measures soil compaction to determine the point at which soils can most efficiently be compacted using construction equipment, based on their optimal moisture content and maximum dry weight. 2. Sand Cone Test is used to determine the in-situ dry soil density and the in- place density of soils. It's especially effective for soils that are granular in nature. It means soils with coarser maximum particle size, like sands and gravels, are ideal candidates. 3. Rubber Balloon Test is an in-situ test conducted to determine field density of soils especially compacted soils. is generally suitable for well-compacted soils. For very soft soils, that deform easily, rubber balloon method is not suitab 4. Dynamic Cone Penetrometer (DCP) Test is the optimum tool for in-place testing of fine-grained soils, pavement base courses, sub-bases, and soil subgrade layers. The DCP provides fast and cost-effective soil strength assessments and layer depth for shallow pavement designs and foundation bearing surfaces. SOIL EROSION The deplacement of the upper layer of the soil, one form of soil degradation. The natural process is caused by the dynamic activity of erosive agents, that is water, glaciers, snow, air, wind, plants, animals and humans. Is the process in which the soil particles are loosened or washed away in the valleys, oceans, rivers, streams, or faraway lands. Types of Soil Erosion 1. Water Erosion Water erosion occurs when rainfall, snowmelt, or flowing water displaces and transports soil particles. 2. Wind Erosion Wind erosion occurs when strong winds pick up and transport loose soil particles. This process is more prevalent in arid and semi-arid regions where vegetation cover is sparse and soils are dry. 5 Agents of Soil Erosion 1. Wind 2. Waves 3. Running Water 4. Glaciers 5. Gravity CAUSES OF SOIL EROSION 1. Natural Factors Rainfall and flooding: Heavy rainfall and floods can generate strong runoff, leading to significant soil erosion. Windstorms: Strong winds, especially in arid regions, can pick up and transport large amounts of soil. Climate change: Changes in rainfall patterns, increased droughts, and extreme weather events can exacerbate erosion. Wildfires: Fires destroy vegetation, leaving the soil exposed and vulnerable to erosion. 2. Human Activities Deforestation: Clearing forests removes trees and their root systems, which help bind the soil and prevent erosion. Agriculture: Practices such as tilling, monocropping, and overgrazing can leave the soil exposed and susceptible to erosion. Construction: Building roads, houses, and other structures can disrupt natural drainage patterns and expose soil to erosion. Mining and quarrying: These activities remove topsoil and expose underlying rock, increasing erosion risk. Impacts of Soil Erosion Soil erosion has far-reaching consequences for the environment, economy, and society: Loss of fertile land: Erosion reduces the quantity and quality of topsoil, making it less productive for agriculture. Desertification: Severe erosion can lead to the expansion of deserts, making land unsuitable for agriculture or other uses. Water pollution: Eroded soil particles and associated pollutants, such as fertilizers and pesticides, can contaminate water bodies, harming aquatic life and affecting water quality. Increased flooding: Eroded land can lose its water-holding capacity, increasing the risk of floods. Loss of biodiversity: Erosion can destroy habitats, leading to a decline in plant and animal species. Soil Erosion Control Preventing and mitigating soil erosion is crucial for preserving the environment and ensuring sustainable land use. Various methods can be employed to control erosion: Conservation tillage: Reducing the frequency and intensity of tillage helps maintain soil structure and reduce erosion. Cover cropping: Planting non-cash crops between cash crops helps protect the soil from erosion and improve soil health. Contour farming: Planting crops along the contours of the land helps slow down runoff and reduce erosion. Terracing: Creating step-like terraces on slopes helps control runoff and prevent soil loss. Windbreaks: Planting trees or shrubs around fields can help reduce wind speed and prevent wind erosion. Reforestation: Restoring forests helps protect soil from erosion and provides other environmental benefits. Landslide The downward and outward movement of slope forming materials composed of rocks, soils, or artificial fills Movement may take place by falling, sliding or flowing or some combination of these factors. Landslides are actually a very extreme, fast-acting method of erosion: Two Categories of Landslide 1. Internal Causes Those mechanisms whithin the mass which bought about a reduction of its shear strength 2. External Causes Those outside the mass involved, which were responsible for overcoming its internal shear strength, thereby causing it to fail. Causes of Landslide - Heavy rainful can saturate the soil and cause it to become 1. Heavy Rainful unstable, leading to landslide. This is commonly in areas with poor drainage systems 2. Geological Factors Such as steep slopes, unstable rock formations, and week soil structures can contribute to landslide 3. Human Activities Such as construction, mining, and deforestation can weaken and cause landslide Can cause landslide by shaking the ground 4. Earthquakes and destabilizing slopes How to Prevent Soil Erosion or Landslide Structure to Prevent Soil Erosion or Landslide 1. Retaining Walls is constructed to resist the lateral pressure of soil when there is a desired change in ground elevation that exceeds the angle of repose of the soil 2. Soil Nailing or rock bolts offer a method of securing excavations, slopes or embankments by installing reinforcement bars through and into the failure zone. Soil nailing usually involves the insertion of reinforcement bars (Hollow/solid) into the exposed slope followed by grouting, placement of a wire mesh and shotcreting before the testing and locking off of the nail through stressing jacks. 3. Ground Anchor or Earth Anchor are strand wire anchors installed in the ground and prestressed to retain shoring structures. These structural elements can used in permanent as well as temporary structures. 4. Sheet Piling resist soil and water pressures by functioning as abeam spanning vertically between points of support. 5. Shotcrete is a type of sprayed concrete used to stabilize slopes and prevent erosion. 6. Drainage Systems are essential for controlling water infiltration and reducing pore pressure in slopes. GEOTEXTILE as any permeable textile material that is used with foundation, soil, rock, earth, etc. to increase stability and decrease wind and water erosion. A geotextile may be made of synthetic or natural fibres Functions of Geotextile: Filtration Separation Drainage Reinforcement Sealing and Protection.