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PLATE 5 <br /> <br /> WEATHERING <br /> Fresh - Rock Ire SD, crysla is bright, Icw jOlnts may show slight stain lnq. Rock rings untler Demmer If cryslalllne. <br /> Very Slight -Hock generally /rpah, joints stalnetl, some joints may show clay If Opln, crystals In Droken lace sDOw bright. <br /> Rock rings untler hammer If cryslalllne. <br /> Slight - Rock generally fresh -joints slai netl antl tllsco lore lion exlentla Into rock up to 1 Inca. Open joint! contain clay. <br />' In granltortl rocks some /e ltlspar crystals are tlull antl tliscolored. Crysld lline rpcka ring under Demmer. <br /> Moderate - 5lgnlflcant portions of rock show alscploratlgn antl weather) ng effects. In granltold rocks most feltliPars are <br /> dull antl tliscOlor<tl; Some snow clayey. Rock has Oull sound untler hammer and Showf fignlllcant loss of <br />t strength ai comparetl with Irish rock. <br /> MDeera telY Severe - All rock except quartz tllscoloretl or stalnetl. In granltold locks all le ltlspars tlull antl discolored antl <br /> majority snow kaOllnlz atlon. Rack Snow3 sever! loss of strength Intl can De excavatetl with geologist's pick. <br />' ROCk goes "clunk" when Struck. (Sapr Olltll <br /> Severe All rock except quartz tllscoloretl or stalnetl. Rock ••labile" clear antl evltlent but retl aced In strength to strong <br /> Boll. In granltoltl rocks all /e ltl3Dars kaolini:ed t0 some lxle nt. Soma Iragments al strong rock usually tell. <br />' (Sapro lice) <br /> Very Severe - All rock except quarts tllscoloretl or stalnetl. Rock •'labile" discern lDle Dut mass effectively retluce0 t0 "s011" <br /> with only Iragments of strong rock remaining. <br />' Complete Rock retlucetl t0 "soil"..Rock ••}abrlc" not tllicern ible Or tliscernl ble only In small scatteretl IocatlOns. Duariz <br /> may be present as tllkea Or stringers. <br />BEDDING THICKNESS AND FRACTURE SPACING <br />' Centimeters Inches Beeein9 Fracture Spacing <br />' P1 0.N Laminated Very Close <br /> 1.5 4r2 Thin Close <br /> 5-30 2-12 Medium Motlerate <br /> 30.100 12-36 TDlck Wltle <br />' 100 36 Very Thick Very Wide <br /> HARDNESS" <br /> <br />' . <br />v <br />H <br /> ery <br />ara - Cannot be scratched with knl}e or sharp pick. Breaking o/ hantl specimens requires several hard blows <br />' Of geologist's pick. <br />I, Hare - Can De scratched with knife or pick only with dlfflcully. Hard blow of hammer requiretl to tletach hand <br /> specimen. <br /> Moaeralely Hartl - Can be scratched with knife or Dlck. Gouges or grooves to W Inch tleep can De excavatetl by hartl <br /> blow of point o} ge Ologlsls's pick. Hantl specimens can be tlelachetl by motlerale blow. <br /> Metlium - Can be 9roovetl 1/16 inch deep Dy /irm pressure on knife or pick polo[. Can be excavatetl In small chips to <br /> Pieces about 1 inch maximum size Dy hartl blows of the point of a geologist's pick. <br />' Solt - Can be gougetl Or grooved reatlily with knife or pick point. Can be ex cavaletl In chips to pieces several inches <br /> in size Dy motlerale blows of a pick point. Small thin pieces can be broken by linger pressure. <br /> Very Solt - Can be tarvetl with knife. Can be excavated reatlily with point o/ pick. Pieces an inch or more in ihrckness <br />' can be broken by linger pressure, Can be scratcnea rea011y by linger nail. <br /> •NOIC: For engineering tlescrrp lion of rock not to be con }urea with Moh's Scale for minerals. <br /> Relere nces: <br />' 1. Subsurface Inve stlgallon for Design antl Constru cllon of Foundations o/ Bulltlings: Part II", by the Task <br /> Committee for foundation Design Manual of the Committee on Shallow Fountlatlons of the Soll Mecha nlcf <br /> and FOUntlatlons Dlv lslon, Journal of the Soli Mechanics antl Fountlalrpns Division, Proceatlings of the <br /> American Society of Clvll Engl veers <br />June, 1972. <br />' , <br />2. ''Description of Geologic Map Unlls San Mateo County, Calllornla", by Ellen, Wentworth, BfaDb antl <br />P <br /> a mpeyan, V.S. Geo logical Survey, 1970. <br />' DESCRIPTION OF ROCK PROPERTIES . <br />