Ground Improvement & Foundation Repair

At the start of a project, if weak soils are encountered on site, one solution is to make deep foundations. Another remedy in this case is to improve the properties of that soil so that it will become denser, stronger and more stable. There are many ground improvement methods available, but the first thing done […]

Rock Mechanics

Just like all the subjects we covered for soil mechanics deal with soil properties, rock mechanics deal with the properties of rocks, in order to utilize them as foundations for our structures, and the same principles apply for determination of those properties, with some minor modifications as required. As in soils, the strength of rock […]

Groundwater Flow nets

Seepage within a soil medium can be shown by flow nets: Groundwater 2a In the figure above we show an seepage flow condition below a dam. The total head anywhere in the water body at the left of the dam is 14m and in the water body at the right side of the dam is […]

Water Head, Hydraulic Gradient, Permeability

Water Head: Since we are explaining subtitle of a subtitle right now, this may seem like a detailed subject in soil mechanics at first… But actually the water head is a very important concept for water resources engineering, one of the five main branches of civil engineering, which we mentioned before briefly and will introduce […]

Critical State of Soil

This is a relatively new (in comparison to many decades old of soil mechanics theories) but very useful concept in soil mechanics. It is a topic that is analysed in advanced soil mechanics courses only, in masters level classes, but it doesn’t prevent us from at least describing it, as it is good to know […]

Slope Stability

Natural slopes tend to slide or fall to their lower side, given long enough time. Depending on the saturation degree of soil, the slope angle, overall 3D geometry, and the soil material itself, this sliding or falling can happen in very different ways and speeds, some can be very slow and virtually harmless, and some […]

Consolidation Settlement

Consolidation settlement is a time dependent settlement that occurs in clay soils, due to applied loads  from above. As we wrote before, settlement of soils in general has three stages: The immediate settlement as the load is applied, which is elastic settlement, the gradual, slow consolidation settlement while water is escaping through soil pores, and […]

Elastic Settlement

After finding stresses in soil, we can calculate settlement amount. Settlement of soils in general has three stages: The immediate settlement as the load is applied, which is elastic settlement, (for all soils) the gradual, slow consolidation settlement while water is escaping through soil pores, (for cohesive soils only) and the secondary compression due to […]

Stress Increase in Soils

Stress Increase in Soils

We have looked at bearing capacity of the soil in the previous section but checking only that is not enough. We must also make sure that, even if the soil can bear the pressure, it will not settle too much.  Before calculating settlement amount in soil however, we must first know the stresses in soil. […]

Bearing Strength of Soil

Bearing Strength of Soil

So far, under soil strength section, we have explained total and effective stresses, pore pressure, angle of internal friction, shear strength, lateral earth pressure coefficient, and cohesion of clay. Now we are ready to start seeing how these are actually used, when designing foundations.   In this subsection we will now learn about bearing strength, […]

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