Civil engineer guide to fighting positions, shelters, obstacles

More documents

Recommendations

Info

AFH 10-222 Volume 14 1 August 2008 144 Attachment 3 FIELD CLASSIFICATION OF SOILS A3.1. Overview. Tests described in this attachment will help in classifying different types of soil in the field environment. These tests are based on information contained in AFJMAN 32-1034, Materials Testing, FM 5-410, Military Soils Engineering, and UFC 3-220-10N, Soil Mechanics. Engineers should become familiar with these references and ensure they are available during deployments. A3.2. Soil Classification. The Unified Soil Classification System (USCS) divides soils into one of three major categories which include (1) coarsegrained, (2) fine-grained, and (3) highly organic. These soils are further divided into major categories based on their properties and characteristics. Table A3.1 contains symbols used to group different types of soils and distinguish soils with different characteristics. These symbols are combined to further describe soils (e.g., GW = well-graded gravel). Table A3.1. Soil Groups and Characteristics Soil Groups Group Symbol Gravel G Sand S Silt M Clay C Soil Characteristics Well graded W Poorly graded P High compressibility H Low compressibility L Organic (peat) Pt Organic (silts and clays) O Liquid limits under 50 L Liquid limits over 50 H
AFH 10-222 Volume 14 1 August 2008 145 A3.3. Field Classification and Testing. Although most tests can be performed without laboratory equipment, using No. 40 and No. 200 sieves provides better accuracy and speeds up testing. Sieves are screens attached across the end of a cylindrical metal frame. The screen allows particles smaller than its openings to fall through and retains larger particles. Sieves with screen openings of different sizes allow you to sort soil into particle groups based on size (Figure A3.1). A3.3.1. Visual Examination. A visual examination can be used to establish the color, grain sizes, and grain shapes of the coarse-grained portion, some idea of the gradation; and some properties of the undisturbed soil. While visual examinations may require a large sample of soil, these tests can usually be conducted with a pint (approximately one canteen cup full) of soil. Soil samples should be taken from the levels of soil that will be exposed during construction and are related to the structural strength of the construction. For example, if soil needs to be tested for a fighting position, the sample should be taken from the exposed wall material that will be a part of the structure rather than the topsoil layer. A3.3.1.1. Colors. Color helps to distinguish between soil types. It can also indicate the presence of certain chemicals or impurities. Colors in general become darker as moisture content increases and lighter as soil dries. Some fine-grained soils with dark, drab shades of brown or gray (including almost black) contain organic colloidal matter. Clean, bright shades of gray, olive green, brown, red, yellow, and white are associated with inorganic soils. Gray-blue or gray-and-yellow mottled colors frequently result from poor drainage. Red, yellow, and yellowish-brown soils result from the presence of iron oxides. White to pink soils may indicate considerable silica, calcium carbonate, or aluminum compounds.
Page 1 and 2:
AIR FORCE HANDBOOK 10-222, VOLUME 1
Page 3 and 4:
BY ORDER OF THE AIR FORCE HANDBOOK
Page 5 and 6:
AFH 10-222 Volume 14 1 August 2008
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96: AFH 10-222 Volume 14 1 August 2008
Page 145: AFH 10-222 Volume 14 1 August 2008
Page 159: AFH 10-222 Volume 14 1 August 2008
show all

Civil engineer guide to fighting positions, shelters, obstacles

Create successful ePaper yourself

Delete template?

Save as template?