Volume of dirt needed?

[HockeyFan]

My wife and I are getting ready to build a 4-module Terra-Dome style underground house. It will be bermed on the north and on the east, but open on the west (the driveway side) and to the south. We will have approximately 3 feet of dirt on the roof. The site is on a relatively level surface. We will berm after construction. I know how to calculate the volume of dirt I need for roof, but since I'm unclear on the slope that I can get away with on the east and north sides of the house, I need help in calculating that. I'd like to order the dirt delivered and have some of it onsite prior to construction, just because it'll be difficult for the dump truck to get behind the home after it is built. I'll be using either a dozer or front-end loader to actually move the dirt up next to the house afterwards. Anyway, can someone tell me the degree of slope that you've been successful with, and also can anyone help in telling me how to calculate the volume of dirt that I will need?

PS. Yes, we are aware that a western exposure isn't energy efficient. However, due to practicalities, this is what we have. However, we are planning a reasonably sufficient overhang, as well as some trees and bushes to deal with the western sun.

[John Reddy]

Hundreds of thousands of years for us to emerge from the caves and you're going back in.

[marson]

As for slope, I don't remember what it is in degrees, but you can pile dirt steeper than you'd want to mow the lawn that will grow on it. Look around at slopes in your area and you'll get a sense of what's possible/practical. There is a building code dealing with sloped dirt next to a lot line, but I don't remember the degree of slope they allow you to have without a retaining wall. Like I say, It's pretty steep (50% slope maybe?). As for calculating volume, if you have a sloped pile of dirt, just estimate the size of a rectangle that is equivilant in area to the cross section of your dirt pile, and multiply by length, etc.

[HockeyFan]

Nice comment. However, I take it as humor, as you obviously don't know much about earth homes. My home will be no more a cave than a penthouse is an attic. In fact, I will have more windows and light into the home than most people's homes. The comment was funny though.

[John Reddy]

Yes, it was intended as humor. I've seen a few such homes and they were pretty nice. Good luck with the project.

[Michael Bulatovich]

Marson is bang on target, with the caveat that different "soils" have different angles of repose. The local municipality might have grading rules you will have to follow.

I'm curious, since I played with these kinds of structures a long time ago...can you post drawings of your project? Everything old is new again.

[Michael Bulatovich]

Seems you have company moving "dirt". Came across this moments later:

GEOLOGY: Leveling the Landscape Brooks Hanson It has been recognized for some time that humans are the most important geomorphic agent modifying our planet's surface, dwarfing the effects of deforestation, desertification, and erosion caused by other processes globally. However, the details of these activities are enlightening, and Wilkinson and McElroy compare the rates of erosion from human activity in different settings with natural processes and with long-term and short-term rates inferred throughout Earth's history. About 5 gigatons (Gt) of sediment per year are thought to have been deposited naturally by rivers during the past 540 million years. There has been high variation about this average, particularly since the Pliocene and during glacial times; the average flux today is about 21 Gt/year. Most of this material (about 80%) comes from mountainous regions where natural erosion rates are highest. For comparison, it is estimated that humans now move about 75 Gt of dirt and rock annually, mostly in low-lying or low -topography areas, and particularly near coasts. This difference implies that large amounts of human-derived detritus are being stored primarily on floodplains and in small stream networks on coastal plains immediately downslope from such areas. This flux greatly exceeds the movement of material by Pleistocene ice sheets. -- BH

Geol. Soc. Am. Bull. 119, 140 (2007).