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>, • <br />TABLE A.3 <br />Weathering Descriptors <br /> <br /> Chemical Weathering•Dlscoloratlpn Alectunkal WealMdng-Grain TexWre ArM BolNlonlrp Ganaral Gturaclerlstlca (§) <br /> Body of Rock Fracture Surlacea (i) BouMary Condltlone <br />Fresh No dlscolpralion, not oxitlited No dlsedaralion or No separation, inta[I (liphp No chan08 No 501utioNng Hammer rings vAien cryslaNrne rocks ale sirpek. <br /> obdalion plmosl always rock exrEVation except for naturally <br /> weak ar weekly cemented rocks such as sdtslones or <br /> shales. <br />Shphlly weathered to <br />fresh' <br />SIIpMIy weathered Discoloration or oxidation is limted to surface of ,or <br />shod tlislance Iron, Lectures: some leldsper Minor to complete <br />tliscoloralmn or oxitlalion of Ne visible separaton, inlacl (light) Preserved Mina leaching of some <br />soluble mnerals tray be Itamner rinBS when crystalline rocks are struck. Body <br />of rock not weakened. Wllh lew exceptions, such as <br /> crystals ore dull moll surfaces noletl slllslones or shales, dashed as rock exGnatmn. <br />Modeately to slipMly <br />weathered' <br />Moderately wealheretl Dlscolorahon or oxidation extends Irom Iradums, All Laclure suddces are Partial separation of Doundarie5 visible Generally Soluble mnerals may De Hammer tloes not ring when rock is struck. Body of <br /> usually Rnoughoul: Fe~Mp nmerals are'msly,' tliscololetl or oxidrzed preserved mostly leachetl rock is slightly weakenetl. Depentlmp en Iradurinp, <br /> leltlspar crystals are'doudy'~ usually Is rock eacavaLgl except m naturally weak <br /> rocks such as slllslones or shales. <br />Innensely 10 nbtlerulely <br />weathered' <br />Intensely weathered Discolorobon or oxitlalion throughout; all feldspars All lradure surfaces are Parlidl separation, mck iS /riable; in T¢xlure Leaching of soluDl¢ Dull sound when shark with tarrvner, usually wnM <br /> and Fe~Mg mnerals ate altered to clay l0 5pnl¢ discolored or oxidrxetl. sertyand contliLOns Branilics are altered by mnerals may be Oroken with moderate Id heavy manual pressure or by <br /> extern; or chemcal alleralion produces in situ suAaces Enable tlisaggregaletl cherracal complete light hammer blow without reference to planes of <br /> tlisagpregalion, see grain boundary condemns tlisinlegralion weakness such as mcipienl or hairline Iraclures, or <br /> (hydration, veinlels. Rock is signihcenlly weak¢netl. Usually <br /> argillalion) convtbn excavation. <br />Ver mlen5el wealh¢r¢tl <br />Deconpusetl Dlscolaed or oxidrzetl Ihrouphoul, but resistant Complete separation of grain boundaries ReselMles a soil, genial w rortplete Can be gra0ulaletl Dy hand. Always common <br /> mnerals such as quartz may De unaltered; all (tlisaggrepatetl) rermanl rock slru<Wre maybe preservetl: excavation. Resistant mn¢rals such as quartz trey be <br /> leltlspars and Fe~Mg mnerals are completely leaching of soluble mnerals usually present as "slnngers'or'tlikesf <br /> altered b clay wnplele <br />Hole: This chart and its horizontal categories are more readily applied to rocks with feldspars and manic minerals. Weathering in various sedimentary rocks, particularly limestones <br />and poorly indurated sediments, will not always fit the categories established. This chart and weathering categories may have to be modified for particular site conditions or alteration <br />such as hydrothermal effects; however, the basic framework and similar descriptors are to be used. <br />Combination descriptors are permissible where equal distribution of both weathering characteristics are present over significant intervals orwhere characteristics present are <br />"in between' the diagnostic feature. However, dual descriptors should not be used where significant, identifiable zones can be delineated. When given as a range, only two <br />adjacent terms may be combined (i.e., decomposed to lightly weathered or moderately weathered to fresh are not acceptable). <br />Does not include directional weathering along shears or faults and their associated features. For example, a shear zone that carried weathering to great depths into a fresh <br />rock mass would not require the rock mass to be classified as weathered. <br />These are generalizations and should not be used as diagnostic features for weathering or excavation classification. These characteristics vary to a large extent based on <br />naturally weak materials or cementation and type of excavation. <br />GEI Consultants, Inc. <br />