Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [geotechnical-engineering]

Geotechnical Engineering is a branch of Civil Engineering focused on the engineering properties and behavior of natural and engineered geomaterials (soils and rocks), as well as the design and construction of foundations, earth dams and levees, retaining walls, embankments, underground structures and tunnels.

Geotechnical Engineering is a branch of Civil Engineering focused on the engineering properties and behavior of natural and engineered geomaterials (soils and rocks), as well as the design and construction of foundations, earth dams and levees, retaining walls, embankments, underground structures and tunnels.

Almost all construction projects involve geotechnical engineering as most structures are built on, in or of geomaterials. Additionally geotechnical engineering involves understanding soil(or rock)-structure interaction for mitigation of natural hazards such as earthquakes and landslides.

A more in depth description and definition can be found at the Colorado Association of Geotechnical Engineers website or at what is geotech?.

94 questions
32
votes
4 answers

Why dig out and then fill in before building a large structure?

I work in the middle of London, in an area full of large office blocks. Across the road from my office they have started construction of a large building (10 stories plus). Over the last few weeks, diggers have dug a large (and vertical walled)…
AndrewD
  • 423
  • 1
  • 4
  • 5
21
votes
1 answer

Why does the Channel Tunnel enter the ground around 10 km from the coast?

I know that digging tunnels is always much more costly than building ways or train above ground. Why doesn't the Channel Tunnel start around the coastline? Why does it have an around 10 km long portion under land on the British side?
peterh
  • 2,394
  • 4
  • 30
  • 46
20
votes
2 answers

Why are earthfills fully covered in concrete where they join bridges?

Here's how a typical earthfill carrying a roadway joins a typical bridge Parts of the earthfill slopes are greenish - that's grass - and parts are whitish - that's concrete. The earthfill slope is fully covered in concrete where it joins the bridge…
sharptooth
  • 2,129
  • 19
  • 28
12
votes
2 answers

Why do earth cuts sometimes have steps on their walls

A neat image from Wikipedia: There're clearly visible steps on the cut wall. This makes the cut wider at the top and so requires more work so those steps have some serious reason behind them. What's the purpose of these steps?
sharptooth
  • 2,129
  • 19
  • 28
11
votes
4 answers

What is the difference between "Crushed Stone" and "Crushed Gravel" aggregate?

Crushing Question While reading a material specification for crushed aggregate, the text mentions both "crushed stone" and "crushed gravel" are acceptable. These materials sound very similar, but they are mentioned individually. I assume that this…
hazzey
  • 10,730
  • 11
  • 46
  • 96
11
votes
2 answers

Soil swelling and mass/volume relationships

Given moisture content, Specific gravity of solids, initial volume, and weight. I'm asked to compute the moist unit weight, dry unit weight, and degree of saturation of this compacted soil. This is already done. This compacted soil sample was then…
Gon
  • 111
  • 5
11
votes
1 answer

How to determine the lateral earth pressure in a double-walled cofferdam?

The design of a retaining wall commonly involves determining the lateral earth pressure using either Rankine theory or Coulomb theory. Both theories involve mobilising the shear resistance of a triangular wedge of soil extending for a considerable…
Question Overflow
  • 824
  • 8
  • 16
8
votes
1 answer

Localized stabilisation of Lunar lava tubes

A study from Purdue University suggests the Moon contains a number of wide underground lava tubes, up to 5000 m wide and about 1500 m high, in which subterranean cities could be constructed. Such tubes would protect potential residents from cosmic…
Fred
  • 9,782
  • 13
  • 36
  • 48
8
votes
1 answer

Why is this construction site pouring gravel over a wire mesh, and then covering it with dirt?

My office is afforded a prime view of a construction project where the workers are currently covering the leveled ground in a wire mesh, raking gravel across the entire mesh, and then covering that gravel layer in another layer of dirt. What is the…
TylerH
  • 186
  • 1
  • 10
7
votes
2 answers

Connections between RC retaining walls and sheet pile retaining walls

I'm working on a flood defence scheme in which a section of RC flood wall becomes sheet piles. The reasons for this aren't important, but the solution isn't to simply make all walls one or the other. My issue is how to connect these two very…
Smeato
  • 364
  • 2
  • 12
7
votes
1 answer

Settling of unevenly loaded storage tank

Suppose I have a concrete tank, round, vertical, diameter in the range 16m-24m. One half the floor is filled with gravel or concrete to a height of maybe 2 meters. When the tank is empty, that will mean I have about 5 tons per m² more weight on this…
mart
  • 4,811
  • 2
  • 19
  • 32
7
votes
3 answers

How are earthfills not eroded before they are overgrown with grass?

Almost every railroad and vehicle road landfill has its slopes overgrown with grass which is quite good at preventing erosion. However it takes some time (a year or more) for the grass to grow and emit enough roots to form a reliable mesh that would…
sharptooth
  • 2,129
  • 19
  • 28
7
votes
1 answer

Boundary condition for a parallelogram-shaped excavation on an embankment

What we learn in engineering school is often idealistic, with textbook examples showing typical prismatic steel beams with a plastic section classification or excavation in a perfect sand or clay geology. However, in the real world nothing is…
Question Overflow
  • 824
  • 8
  • 16
6
votes
2 answers

Should P-Δ effect be considered for struts of a braced excavation?

Building codes such as BS5950 provide clear guidelines on how to consider P-Δ effect due to sway of a vertically loaded portal frame or single storey building, causing additional moment in the columns. Should this sway frame effect be extended to…
Question Overflow
  • 824
  • 8
  • 16
6
votes
2 answers

How are the structural properties of intentionally frozen soil determined?

Soil freezes naturally all of the time. It is at this point that dirt work usually stops. Occasionally soil is intentionally frozen to improve its structural properties. This process has been used notably in Boston's Big Dig and the Fukushima…
hazzey
  • 10,730
  • 11
  • 46
  • 96
1
2 3 4 5 6 7