I was doing a retaining wall practice problem with partially submerged soil. Why do you consider a rectangular area for soil under the water table and use dry unit weight? Doesn't make sense. I thought pressure distribution was triangular?
Hi everyone, as part of my senior capstone project I'm required to determine seismic lateral earth pressures for select basement/retaining walls for a school. One wall in particular is 28 feet high, is restricted on one side by two floor slabs (at mid-height and top) and is "holding back" 15 feet of sedimentary rock (siltstone/sandstone) and 13 feet of clayey silt fill. Additionally, plans call for providing granular backfill within 2 feet of the wall. Should I consider the wall friction angle with respect to the backfill, and what other impact does the the backfill have on calculating these pressures? Or should simply ignore it and design solely for the existing layers? (Note: the uppermost floor extends further beyond the wall, but I am ignoring this condition for simplicity.)
In what cases is the seismic lateral pressure assumed to be an inverted triangle?
Also, do you advice the use of the at rest pressure or the active pressure together with the seismic lateral pressure ?
Thank you
Hello. I often receive geotechnical reports that do not provide a lateral earth pressure recommendation or friction angle, but need to come up with a good assumption based on the soil classification to use for preliminary design. Is there a good geotechincal resource that provides typical Ka and Ko values for different soil classifications? I realize this is not as precise and therefore I tend to increase my FOS / load factor a bit, but I like to have a good reference to go off of. Thanks.
Having a bit of trouble with lateral earth pressures. Have previously calculated lateral earth pressures in soils using rankines model with Ka and Kp derived from the friction angle of the soil.
How do you calculate the Ka and Kp for sandstone rock? All the information I can find refers to soil.
For context, this is a question in regards to a deep (10m) basement excavation with concrete pile shoring.
What method do you use to calculate the seismic component for an at-rest (basement wall) condition? Wood is the only one that Iβve seen but itβs extremely conservative. Thoughts?
I recently changed the laterals and the sand in my Hayward S244T sand filter. For the past week Iβve had to backwash every 2-3 days. Normally, itβs 7-10 days. My PSI is going from 12 to >20 by 24-36 hours. Is that normal after a sand change? I used the Hayward laterals, correct amount and type of pool sand per manual.
I'm no aerospace engineer, but I'm finding it hard to fathom how the current Starship, having been designed to land using Earth's relatively dense atmosphere, is going to be able to land on Mars. 1% of the atmosphere even combined with (only) 38% of the gravity of Earth seems like a significant impediment to overcome, given the basis of design of Starship. I do realize that we are early in the process.
I've seen all sorts of graphics of cities on Mars surrounded by multiple landing pads with Starships, but the spacecraft looks identical to the earthbound version. Seems to me that the current iteration would produce a massive, smoking hole in the ground if it tried to land on Mars, and a version that could land on Mars would need to look very, very different. I can understand how some variation of the current design could get to the moon's surface, but can't envision Starship's fundamental principle of using drag to decelerate as it nears the surface being effective. Seems like carrying (a massive amount of?) propellant to decelerate would obviate being able to get 100 people to the surface.
Has Elon ever elucidated how this will be addressed?
Iβve been looking around and it appears a stronger way is to drill the hole and use chemical resin with a sleeve to help with adhesion. I have no way of knowing how thick the tarmac is outside my house. Are there any other easy methods of installing things onto tarmac. Thanks.
Ive been noticing in the evening when Iβm deep in my thoughts in the dark, and in dark thoughts, that I can almost idk, feel a subtle pressure on my upper back muscles, the ones by the shoulder blades, i donβt usually think or imagine this kind of thing, Iβve only recently gotten interested in things beyond the physical world.
But I randomly imagine a small rather cute set of dark ambiguous color perhaps closest description could be purple black pert upright wings gel like and full in dimension protruding from my back/shoulder blades and it flexes and I can feel the flex in my upper back. I havenβt been as fit as I normally am but it feels almost like when I do lateral wing weight machines at the gym, itβs very pleasant. I chalked it up to gaining fat or something on my back/body perhaps causing a gravitational pressure.
I just googled it though and there actually seems to be some pre described phenomena of energy wings. First time Iβve heard of anything like that. Is this just imagination and wishful thinking?
When I put lateral pressure on my skates (powerslide phuzion, trinity system frame) I hear a clicking sound. It's especially noticeable if put weight on a skate with my foot fully pronated or supinated.
It seems to be just on my back wheel, where I've used adjustable spacers to set it so the Bearings + spacer are slightly wider than the wheel. I've done that because otherwise the wheel doesn't spin freely. So I'm fairly sure the noise is the wheel moving side to side across the spacer and clicking on the "shelf" inside the wheel. Has anyone else had this issue? Is there a way to get the skate to spin freely without making the spacers wide?
Or is it possible I'm totally mistaken and something's wrong with the frame?
"All other things being equal," if instead of 9.8m/s^2 we had half that gravitational pull at sea level, would atmospheric pressure also be half? The reason I'm asking is because I'm trying to conceptualize what flying would be like with our level of technology on a planet will lower gravity.
Would it become easier to fly since you have to overcome less gravity, or would it be harder because you need more lift due to the atmosphere being thinner, or would it be relatively the same, because the lower gravity would result proportionally similarly lowered density?
My brain latched onto this and couldnt shake it. Imagine earth is a pebble in a bowl of water. Gravity is the pressure of that water against the pebble. Now replace water with 'space'
It was early and I was half awake. I also havent researched the science on gravity so this is probably also shittyaskscience hah.
I know the make-up of Earth's atmosphere has changed a lot over time, but has the overall air pressure stayed the same since the Earth solidified? Or does a palpable amount of hydrogen get blown away by solar winds on a geological timescale?
If I opened a portal through time, what would happen at different points in history? How quickly would the air flow inwards/outwards and mix?
Thanks in advance for any & all answers!
I learned this from Andrew Huberman, Ph.D., a professor at Stanford who studies how vision and our brains are interconnected.
Friends of mine are going to be using earth bags to build an assembly of domes that will come to be their new home. The plan consists of four separate domes (a living room with a diameter of 11 feet, a kitchen d=11ft, a bathroom d=10ft, and a bedroom d=13ft) connected by straight hallways with arched roofs. The domes will be as tall as they are wide to remain structurally sound.
Surrounding the domes, they would like to build a 4ft tall snaked wall that would become a raised garden bed that encapsulates the domes. The garden will serve as a thermal mass which keeps the domes climate controlled. However, they are worried that the force that the soil exerts on the domes would be too great. To counteract this, we were thinking that maybe 4 foot tall self contained cylindrical planters within the raised garden bed would help reduce the force being exerted onto the domes by containing a large portion the soil within the cylinders.
Our question is, would several cylindrical planters within the raised garden take the load off the domes in the middle? Please let me know if I can make anything more clear or answer any question regarding the domes or the raised garden bed.
They get right up my nose.
It's currently almost 1am and I can't sleep. I had homework and a test (technically) today and I didn't study/do them because I'm busy trying to survive this.
My doctor prescribed me premavig which helped for 2 weeks until today I'm back to my annoying bs and I'm sick of it.
I'm just ranting and in need of a bag to punch out of frustration. I've always had headaches but before they were easily removed by simple panadol.
I miss those days.
Now I've had my first migraine attack and even the strongest painkiller my doctor can prescribe isn't working.
Life sucks sometimes.
