32

The picture, below, of the exaggerated long section of the Channel Tunnel was taken from Wikipedia. Full-sized image here. Some of the limiting factors for the Channel Tunnel are: Railways don't like steep gradients The tunnels comprising the Channel Tunnel were excavated using tunnel boring machines (TBMs). Like railways, they cannot tolerate steep ...


30

This is to make sure they know what the foundation is made of. For all they knew there may have been an old tunnel underneath that would have collapsed when the new building is put on top. London is built on top of an old marsh, this type of soil is very prone to sinking and uneven settling, digging down and reinforcing the foundation alleviates that. It ...


24

This is called Slope Paving. (In the US at least.) It is done for two reasons at bridge abutments. These reasons are related: Steeper slopes are possible. Protection from undermining abutments and piles. Steep Slopes The soil that is used to create the earthen fills will only stand up naturally to a certain steepness. By placing a layer (~4in) of ...


21

There are a few reasons why the footprint of large buildings are excavated and replaced. All of the old building must be removed - Typically, older buildings will have been built with weaker materials or less stringent building standards than are currently used. Depending on the age of the existing structure, complete plans may not even exist. This means ...


20

The main reason for the stepped arrangement of the slope is slope stability and safety. Such walls/cuttings are divided into two components: sub vertical walls between two flat horizons flat sections between sub vertical walls By having a stepped arrangement, material and hence weight, is removed from above the toe of slope (where the bottom part of the ...


11

The primary difference between Rankine and Coulomb earth pressure theories is that Coulomb's considers a frictional retaining wall. In other words, the interface between the soil and the retaining wall is not assumed frictionless (as it is in Rankine theory). That being said, it is typically considered that Rankine underpredicts the true orientation of the ...


8

This is a pretty huge topic, but I can summarize a couple major factors. More population, more damage, more awareness The effect of a disaster that kills thousands of people and causes property damage in the billions of dollars (current equivalent) is felt much more intensely than that of a disaster of similar magnitude that affects a much smaller ...


7

Because they're two completely different systems that have, in some circles, accidentally been given the same names. The things that are sometimes (particularly in the USA) called home geothermal systems are ground-source heat pumps. The energy for these comes from sunlight on the ground over the year. Electricity is used to move heat from a source ...


6

From what I read, you are looking at the pressure the sand between the sheet piling exerts on them. In this case, I see two possibilities: (1) log-spiral analysis or (2) elastic analysis of Boussinesq. Log Spiral Analysis The log spiral analysis assumes that soil pressure is mobilised by a soil mass that follows the shape of a log spiral curve. This is ...


6

All these terms refer to the effect of loading on the deformation of materials. Let us assume that we start with zero load and zero deformation. Elastic deformation If you increase the load you get an increase in deformation. During the process of elastic deformation, if you decrease the load to zero you will not have any residual non-zero deformation. ...


5

The flat "table" area in the middle of the curve indicates that particles of roughly 1–4 mm diameter are not well-represented in your aggregate. This gap in your particle size distribution is why it's called gap-graded. Basically, you want to look at the slope of the curve in different regions to tell whether particles are accumulating in the sieves of ...


5

Bolts Flanges can be added to the members as Wasabi mentioned in his answer. Another option would be to cut a small hole in the web of the members to allow for an iron worker to insert his hand to insert a bolt or hold a wrench. The reduction in strength from the access holes is minimal. This type of access is also used in the bolted connections of truss ...


5

The slope angle of such slopes is constructed to be less than the angle of repose for the material used in the slope. The angle of repose is the great angle to which granular materials can be dumped without slumping. The higher the cohesiveness of the material, the higher the angle of repose. Stability of such a slope will be improved by compacting the ...


5

There are a few methods that are used to control erosion before permanent vegetation is established. The exact method used can depend on location (also country), season, preference, governing laws, etc. Mulching This is almost always done. Mulch is frequently straw but can also be ground up newspaper. This helps to initially keep the soil from eroding while ...


5

Whether it's natural subsidence, like sinkholes or human induced subsidence like the collapse of underground engineered chambers or mining subsidence the two ways of dealing with it are backfill or leaving it alone and the enforcement of an exclusion zone. Where backfill is used for the remediation of subsidence it's generally loose rock fill, because it's ...


5

If one side of foundation has soil packed more loosely than the other side, the foundation may cause the ground to sink, and building may crumble. Even if it has a steel-reinforced concrete foundation, the building may tip sideways, causing uneven floors, or wood to shift and split, even if concrete remains in same shape. In my area we have a lot of caves, ...


5

Here's a really (and I mean really!) quick and dirty set of calculations that might give you an idea of the magnitudes of settlement you could be dealing with. The settlement potential of the tank location can be determined a number of ways, but probably the best thing to do would be a plate load bearing test. The test can be run to simulate the range (...


5

Beyond a certain level of saturation, the bulk modulus of water starts playing an important role. Since water is nearly incompressible at moderate pressures, the pore pressure increases rapidly and equilibrates with the externally applied force when we try to compress the water. This makes it difficult to compact fully saturated soils and partially ...


4

The given information describing a compacted soil sample is as follows: initial moisture content, $\omega_{init}$ specific gravity, $G_s$ initial volume, $V_{init}$ initial weight, $W_{init}$ For completeness: the following information has already been determined: moist unit weight, $\gamma_{wet}$ using the relationship $\gamma_{wet}=\frac{W_{init}}{V_{...


4

They lay turf pads down to kickstart the grass coverage. Even the loose pads will have better erosion protection than bare soil. Other options include laying down a sheet with holes for plants/shrubery to grow through, the sheet will let enough rain through to let the plants grow but prevent the hillside from eroding until the planted shrubs are robust ...


4

Double-I beams cannot be spliced like single-I beams for the reasons you mentioned. Indeed, they must be spliced like box beams, which suffer from the same problems (lack of access to internal face). To deal with this, it is common to weld plates at the ends of the beams to be spliced and then bolting the plates together, as seen below (source):


4

It's of importance to note that historically, "stone", "gravel", and many other related terms have great regional variability. It is always advised to make certain what is meant by such terms when they are being used. Although the term "gravel" does have a specific engineering definition (aggregate of a certain size range), in design specifications the ...


4

They are both correct. There are actually a number of different types of geothermal power plant with the most common being, dry steam, flash steam, and binary cycle. Dry steam plants require pumps to draw from underground resources of steam. This is piped directly from underground wells to the power plant. Flash steam plants (most common) use geothermal ...


3

The optimum moisture content is defined as the moisture content where you get maximum dry unit weight. So plot moisture content ($w$) vs dry density ($\rho_d$) and locate the maximum. Without any interpolation (i.e. if we have to pick a value from your table) this occurs at $12.3 \%$ moisture content, and corresponds to a dry density of $2001.27 \frac {kg}{...


3

For a more complete discussion see: ACI 421.1R-08 - Guide to Shear Reinforcement for Slabs. But in principle you need to continue to provide punching shear reinforcement until the shear capacity of the slab is sufficient to prevent punching shear at that perimeter. From ACI 421.1R-08 this means: You need to check at $d/2$ from the column face to determine ...


3

I am unaware of a torsion test for rock. Shear, compression & tensile strength tests yes, but not torsion. All the civil engineers, mining engineers and geotechnical engineers I have worked with over the years have used shear, compression and occasionally tensile strength of rock. No-one ever mentioned torsion strength.


3

You don't need satellite images to make accurate maps. Accurate surveying techniques have been around for a very long time and are essentially based on fairy simple technology. The basic principals of surveying require the ability to measure direction, elevation and distance relative to some fixed reference point and some basic geometry can allow you to ...


3

You are correct, this is the subbase that the foundations will be built on top of. The gravel can be used as you say for water run off but it also allows for a level base on which to lay the concrete. In areas where the ground becomes highly saturated it can protect the concrete foundation from erosion. The wire mesh is usually used for load-bearing ...


3

I've done some searching, according to this converter kps or KPS stands for Kilo Pascal, but don't use that abbreviation. The actual abbreviation for Pascal is Pa, and for kilo a small k, combined kPa. Thus: $$ 1\hspace{1mm}\mbox{psf} = 47.88\hspace{1mm}\mbox{Pa} $$ With that assumption, are your values in a reasonable range? I assume that kips in the ...


3

The water table in some locations may vary during the day or over time. For this reason, the borehole drilling process includes waiting periods to see if there are any changes to the water table. The depth at which the borehole initially finds the water table may be incorrect, an artifact of the drilling process itself. Therefore, if any changes to the ...


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