Relative Density | unitracc.de

Importance of Relative Density: <p/><p><strong>Why is it important to know the relative density of the soil?</strong></p><div class="clearfix layout-row marginalia"><div class="layout-column side-note"><div>(Image: Attention!)</div></div><div class="layout-column text"><p>The relative density is used to identify the arrangement of the individual grains of coarse soils to one another.</p><p>With this information it is possible to draw immediate conclusions in regard to the soil stability or displacement capability, and water permeability of the soil within the excavation.</p></div></div><p/><p/>
Types of Bedding: <p>Assuming an ideal <strong>single size grain</strong>, there are only <strong>two types of bedding</strong>:</p><table><tbody><tr><td> (Image: Loose bedding of single size grain soils in accordance with [Soos96])</td> <td> (Image: Dense bedding of single size grain soils in accordance with [Soos96])</td> </tr></tbody></table><p/><p>In the case of the <strong>loose bedding</strong>, the individual soil grains are able to move relative to each other.</p><p>The <strong>dense bedding</strong> represents the natural bedding form of single size grain soils. Here, the soil is as solid as a rock; …</p>
Relative Density of Non-Cohesive Soils: <div class="clearfix layout-row marginalia"><div class="layout-column side-note"><div>(Image: Attention!)</div></div><p class="layout-column text">The term “<strong>Relative density</strong>” only applies to non-cohesive soils.</p><p class="layout-column text">Non-cohesive soil can only be loosely and imperfectly compacted under a direct static load, however the compaction can be significantly improved by means of tamping or vibration.</p></div><p/>
Soil Composition: <table><tbody><tr><td> <p class="converted-h3"/></td> <td></td> <td> <p class="converted-h3"/></td> </tr><tr><td> <p>The soil is a multi-phase system composed of the following three phases:</p><ul><li> <p>Mineral components (solid phase)</p></li> <li> <p>Water (liquid phase)</p></li> <li> <p>Air (gaseous phase)</p></li> </ul><p>Soils can be composed of the following phase combinations:</p><ul><li> <p>Solid-liquid</p></li> <li> <p>Solid-gaseous</p></li> <li> <p>Solid-liquid-gaseous</p></li> </ul></td> <td></td> <td> (Image: The soil model)</td> </tr></tbody></table><p/>
Important Soil Characteristic Parameters: <p>The volume ratio between the three phases is described by the following parameters:</p><div class="clearfix layout-row columns-2"><div class="layout-column first column-1"><p>(Formula: Void ratio)</p><p>(Formula: Porosity)</p><p>(Formula: Degree of saturation)</p></div><div class="layout-column last column-2"><p>(Image: Soil void ratio)</p></div></div><p/>
Relative Density: <p>The higher the pore volume in relation to the total volume, the lower the density.</p><div class="clearfix layout-row marginalia"><div class="layout-column side-note">(Image: Density)</div><div class="layout-column text"><p>Relative Density: D = (n<span>max</span> – n) / (n<span>max</span> – n<span>min</span>)</p><p>Density Index: l<span>D</span> = (e<span>max</span> – e) / (e<span>max</span> – e<span>min</span>)</p><p>Compactability: l<span>F</span> = (e<span>max</span> – e<span>min</span> ) / e</p></div></div><p/>
Relative Density of Non-Cohesive Soils: Classification: <div class="clearfix layout-row columns-2"><div class="layout-column first column-1"><p>A classification and designation of non-cohesive types of soil (sands and gravels) subject to their relative density depends on a number of factors, such as:</p><ul><li> <p>Test procedure</p></li> <li> <p>Overburden pressure</p></li> <li> <p>Pre-loading</p></li> <li> <p>Particle size distribution</p></li> </ul></div><div class="layout-column last column-2"><p>Using the relative density D and the density index l<sub>D</sub>, it is possible to determine the compaction of a soil sample.</p><p>(Table: Classification of non-cohesive soils according to density, N value and inner angle of friction)</p></div></div>
Standard Test to Determine the Relative Density of the Soil: <div class="clearfix layout-row columns-2"><div class="layout-column first column-1"><p>The standard test used to determine the compaction of soil samples in the laboratory is the proctor compaction test per [[ASTM D698]] and [DIN18127:1997]. Compaction in accordance with this standard is “to increase the dry density (decrease the pore percentage) of the soil by means of mechanical impacts” [DIN18127:1997].</p></div><div class="layout-column last column-2">(Image: Manual proctor devices)</div></div><p/>
Proctor Compaction Test: <div class="clearfix layout-row columns-2"><div class="layout-column first column-1"><p>The proctor compaction test described in [[ASTM D7263]] and/or [DIN18127:1997] is used to determine the influence of the water content onto the achievable density of a soil sample.</p><p>The soil sample is placed into a cylinder and is then compacted through tamping with a weight at different levels of water content. The drop height, weight and number of blows are the defining parameters. The maximum density is achieved at a particular water content, and …</p></div></div>