Now let’s give a simple example to wrap things up. This example will use many things we have learned so far, not only in soil mechanics, but structural basics section too. We have a gravity retaining wall here, which is a type of retaining wall that resists overturning effect of retained soil by its weight. […]

In designing retaining structures, the most critical thing to know is how much horizontal (lateral) pressure the retained soil will exert on the retaining structure, such as a retaining wall. In previous post, we learned how to calculate the vertical stresses soils. Here, we must somehow derive horizontal pressure from it. To do this, we […]

We introduced shear stress before in this book. If you are not an engineer, and forgot what shear stress means, first please go back to section Structural Basics > Forces and look at again, what it means “shear”. Now, Imagine the following different situations: Think of water running down a sloped street. It can flow, […]

Before we move on here with soils, let’s talk about fluid pressure first. The pressure of any fluid (liquid or gas), such as water, increases constantly with depth such as: Pressure = Unit Weight of the Material x Depth Written in correct terms: Pressure = γfluid x d, where, γ: the unit weight of the […]

This is the heart of soil mechanics, where we calculate the stresses in soil, and how it will settle based on these stresses, in other words, strength of soil. It mainly contains the following topics, which we will introduce each below. Total stress, effective stress (soil skeleton stress), pore water pressure Shear Strength of […]

From strongest to weakest, soils can be listed in order as: Rock > Gravel > Sand > Silt > Clay > Organic Soils The word “strong” here, means shear stress supporting ability, which in turn means bearing capacity of the soil, which basically means, load carrying capacity of the soil. These will be talked about […]

Let’s start with the basics, phase relationships, which is the first thing to learn in soil mechanics… Any given soil volume contains solid particles, water, and, if it is not fully saturated, air too. Phase relationships define the volume and weight relations in soil for solids, water, and air. These relationships are fundamental to know […]

So far in this post series, we introduced the most basics of structural related concepts, (most of which of which we will also use in this section too) and now we can move on to geotechnical branch of civil engineering. As we mentioned before, geotechnical branch is mainly separated into two as soil mechanics and […]

After discussing stress and strength, the next important item to know is the relation of stress versus deformation. Imagine a material which is somehow perfectly rigid. In other words, it never deforms, no matter how large, even infinite, load you apply on it. In nature no such material exists. Every material, no matter how strong, […]

In many cases, when performing structural or geotechnical calculations, it is important to know the possible effects of stresses that act on materials not from just one direction, as we saw above, but from multiple directions, which happens quite a lot. The effect of stresses acting from multiple directions will cause the materials to fail […]