Browse Forums Building A New House 1 Jan 18, 2015 7:24 am Can anyone tell me what "carbonates" refer to in a soil test profile? Does it mean carbonate rock ie limestone or dolomite or does it mean carbonate soil? And what exactly does "weathered rock" mean? Is there any rock that isn't weathered? Sorry but I didn't do any geology after Year 9. Re: Understanding soil tests 2Jan 18, 2015 7:44 am Carbonates - it normally means the soil (clay) has a fair bit of sodium carbonate, which causes swelling. Risk of soil heave. Weathered Rock. Usually the outer layer of a rock band that shows evidence of being affected by the weather, or water if buried. Commonly in an excavation you will first find weathered rock followed by solid rock. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Understanding soil tests 4Jan 18, 2015 12:07 pm It usually means calcium carbonates which is a mineral that leaches through basalt clay its white and generally reduces reativity of the clay but they clay above it can be more reactive.its a bit like lime stabilisation. You can get almost pure layers of it or it can be disbursed through the clay. Bashworth is right that sodium is the principle cause of swelling in highly reactive clays but calcium carbonates reduces the reactivity. http://i1028.photobucket.com/albums/y342/jmfieldwork1/IMG_7404_zpsf63f7c6b.jpg Re: Understanding soil tests 5Jan 18, 2015 7:27 pm Hi insider, Thanks for the picture and the explanation. The +Carbonates/Weathered rock were found at a depth of about 1300mm under grey and light grey clay but only at one borehole. There was an END-UTP FLOATER at 1200mm at another borehole and grey clay in the third. Re: Understanding soil tests 6Jan 18, 2015 8:41 pm Yes typical western suburbs basalt soil profile Class" H2" normally, the photo is from harpley estate in werribee. Floaters are round rocks in the soil,not bedrock and can even be on the surface sometimes. ask the surveyor for clarification would be the logical approach 1 20145 I am not sure whether Perth has its own way of doing things in regards to this. Most of Perth has class A (sandy soil), except for some areas near rivers or hills. 2 13106 We were lucky in that our old house was so small (86 square metres) compared to the new house, they were able to take enough readings around the old backyard house before… 8 37159 |