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Page 1 6 Supp l emen ta ry I nfo rma t i on PROPOSED F I LL S 1 . 0 SO I L I NVE ST I GAT I ON The s o i l i nves t i ga tion s hou l d p rov i de i nforma t i on on the phys i ca l cond i t i on of the s i te a s we l l a s of the fi l l mate r i a l p ropos ed . The exten t of the s i te i nves t i ga t i on requ i red depends upon the th i ckness of the f i l l , t he p roposed s t ructu res , and the so i l cond i t i ons and topog raphy found a t the s i te . The extent of exp l ora t i on a t the bo r row sou rce or sou rces depends on the quan t i ty of f i l l requ i red and the type of mater i a l found and p roposed fo r use as a f i l l . S i te I nves t iga t i on A reconna i s sa nce of the s i t e s hou l d p rov i de da ta wh i ch w i l l a i d i n de te rm i n i ng t he feas i bi l i ty of the p roj ect , f i na l i z i ng the p roj ect p l an s , and p l ann i ng t he s ubsu rface s o i l i nves t i ga t i on . The reconna i s sa nce s hou l d i nc l ude exam i nat i on of geo l og i c , pedo l og i c , and a i rphoto maps of the a rea , for i nforma t i on on the na t u re , o rigin , and d i s t r i but i on of s o i l s a t t he s i te , a l so for i nfo rma t i on conce rn i ng t he topog raphy , and conce rn i ng g round- and s u rface-wa t e r cond i t i ons , i nc l ud i ng d ra i nage patte rns . I nfo rma t i on about the pe rformance of ex i s t i ng f i l l s and founda t i on s i n the a rea may be obta i ned by v i s ua l i ns pect i on of t he s i te and nea rby a reas , and by i nqu i r i es at the c i ty bu i l d i ng depa rtment . Ce rta i n a reas a re undes i rab l e for , but not exc l uded f rom , hyd ra u l i c f i l l app l i ca t i on , because of t roub l esome na tura l s o i l cond i t i ons and t he accompany i ng inc rea sed cos t s . Among these a re t i da l l a goons , t he a rea beh i nd a ba r r i e r beach , t i da l ma rshes , de l tas a t the mou ths of l a rge s t reams , e s t ua ry f i l l i ngs at the ends of s t reams , and othe r p l aces whe re f i ne- g ra i ned ma te r i a l i s depos i ted i n a body of wa te r ⢠⢠Such depos i t s and l and fo rms may be recogn i zed du r i ng reconna i s sance and avo i ded . G round wa te r i s not a p rob l em du r i ng p l acement of hyd ra u l i c f i l l but may i nf l uence t he use of a s ubsu rface sewa ge absorp t i on f i e l d. La rge s e t t l emen t of nea rby fi l l s o r founda t i ons , pa rt i cu l a r l y i f i t occu rs ove r a pe r i od of yea rs , i ndica tes potent i a l p rob l ems at the s i te of the p roposed f i l l and t he need
Page 1 7 Supp l ementa ry I nforma t i on for a t ho rough s o i l i nves t i ga t i on . Se i sm i c act i v i ty i n t he a rea req u i res ca re i n dea l i ng w i t h l oos e , sa t u ra ted , coa rs e-g ra i ned ma te r i a l s , e i the r i n na t u ra l unde r l y i ng so i l s or i n p l acement of hyd rau l i c f i l l s , s i nce the re i s a potent i a l dan ge r of l i quefact i on of so i l s w i th a dens i ty l es s t han t he c r i t i ca l dens i ty . So i l i nves t i ga t i on p rocedu res cannot be s tanda rd i zed ; each s i te mus t be s tud i ed and eva l ua ted as i t s cond i t i on s d i ctate . A m i n i mum p rog ram of i nves t i ga t i on has been out l ined i n the recommenda t i ons of Sect i on I l l , pp . 5 - 1 4 . The i n ten t i s to p rov i de s uff i c i en t i nforma t i on to pe rm i t d raw i ng of s o i l p rof i l es mak i ng c l ea r the exten t and th i cknes s of t he so i l s trata p resent a t the s i te . I n cor re l a ting the f i nd i n gs f rom the bor i n gs and p rob i ngs , the con t i nu i ty of s trata as we l l a s the extent of l enses of va r i ous s o i l s s hou l d be dete rm i ned and p resented . The resu l ts of the reconna i s sance shou l d be u ti l i zed i n p l ann i ng the numbe r and l oca tion of bor i ngs and samp l es . Fo r examp l e , port i ons of t he s i te i nd i cat i ng f i ne- g ra i ned depos i ts , such as f i l l ed d ra i nage channe l s , s hou l d be bored and samp l ed . For f i ne g ra i ned s o i l s of med i um and softe r cons i s tency 1 , or a s o i l on wh i ch t he ASTM D 1 586-58T pene t rat i on tes t 2 ind i ca tes 1 0 b l ows or l es s per foot of pene t ra t i on ( i nd i ca t i ng tha t l oose g ranu l a r ma te r i a l o r soft f i ne-g ra i ned s o i l i s p robab l y p resent ) , und i s tu rbed s o i l samp l es for l aboratory tes t i ng a re requ i red . For a l l othe r s o i l s , re l a t i ve l y und i s t u rbed samp l es s hou l d be obta i ned i n acco rdance w i t h the ASTM D 1 586-58T p rocedu re . A m i n i mum bor- i ng p rog ram i s def i ned to a s s u re that the natu ra l s o i l s a re exam i ned and tes ted to a dep th s uff i c i en t to ens u re adequa te s uppo rt for the f i l l s t ruct u res . To as s u re an adequa te i nves t i ga t i on , at l eas t one bor i ng s hou l d penet ra te t h rough a l l 1As def i ned i n Append i x E, p . 32 . 2ASTM Des i gna t i on D 1 586-58T , Ten ta t i ve Met hod for Pene t ra t i on Tes t and Sp l i t -Ba r re l Samp l i ng of So i l s , Ph i l ade l ph i a : Ame r i can Soc i ety for Tes t i ng and Ma te r i a l s .
Pa ge 1 8 Supp l ementa ry I nforma tion weak or comp res s i b l e s o i l s to rock or ve ry dens e ha rd soi l . Th i s bo ring s hou l d be l oca ted whe re comp ressib l e ma te r i a l i s l i ke l y to exis t ; it s hou l d a l so ref l ect con d i t i ons in the a rea of heav i est l oads . Addi t i ona l bor i ngs at each bui l d i ng s i te , but not fa rthe r apa rt than 500 feet , a re needed to obtain the i nformat i on nece s s a ry to cons t ruct a geo l og i c c ros s -section of the area . Wheneve r i t is eviden t tha t the re is uniform i ty of cond i tions and the bu i l d i ng sites a re l es s t han 500 fee t apa r t , a g rid of borings at inte rva l s not g rea te r than 500 fee t w i l l nonma l l y suffice for th i s pu rpose . Due to the na t u re of f i l l l oading--a consequence of f i l l height and a rea l extent , pa r t i cu l a r l y i n connection w i th the us ua l hyd rau l i c f i l l s i te- - t he l oa d effects a re t ransmi t ted to conside rab l e dep t h . The refore , bor i n gs mus t be ca r ried to a dep th wh i ch c l ea r l y ind i ca tes that no weak o r comp res sib l e soi l s , s uch as o rgan i c c l ays and s i l t s ( OL and OH) , soft inorganic c l ays and si l t s ( ML , CH , MH , and CH) , and l oose s ands and g rave l s , wi l l be adve rs e l y affected by a pa rticu l a r l oa d i ng . O t he rw i se , adequa te ana l ys i s and eva l ua t i on is not pos sib l e . The i nves t i ga t i on of the sou rce o r s ou rces of bo r row mate ria l s hou l d p rovide s o i l s amp l es rep resen tat i ve of conditions to t he dep th to which d redg i ng equipment wi l l ope rate , wit h a common maximum dep t h of sixty fee t be l ow wa te r l eve l a s s umed . Know l edge of t he amount and l ocation of mate r i a l uns u i ta b l e for fi l l which s hou l d be removed befo re d redg i ng f i l l materia l i s of i mportance . Labora tory Tes t i ng The p rog ram of l a bora tory tes t i ng depends upon t he site and s o i l s i nvo l ved . The recommendat i ons i n Section I l l , pp . 5 - 1 4 , p rov i de min i mum requi rements needed for evaiuation of t he soi l p rope rties . Conso l ida tion tes ts a re requi red of pea t , organic si l ts and c l ays , s of t i no rganic c l ays , and sof t s i l ty c l ays which unde r l i e the si te , because s i gn i f i cant l on g- te rm s e t t l ement p rob l ems can occu r w i t h - �-
Pa ge 1 9 Supp l ementa ry I nforma t i on these s o i l s . When f i ne-g ra i ned s o i l s s amp l ed i n acco rdance w i th t he ASTM D 1 587-58T t h i n-wa l l ed tube s amp l i ng p rocedu re 1 have , o r appea r i n the f i e l d to have , an unconf i ned comp res s i ve s t rength of l es s than 3 , 000 psf; und i s tu rbed so i l s amp l es s hou l d be ob ta i ned for l abo ra to ry s t reng t h tes t s . P red i ct i on of the behav i o r of a comp l e ted f i l l Is not pos s i b l e excep t for coars e- g ra i ned , re l a t i ve l y pe rmeab l e , f ree- d ra i n i ng f i l l so i l s s uch a s g rave l s and sands w i t h l i t t l e o r no f i nes ( GW , GP , SW , and SP ; GM and SM may be i nc l uded i n t h i s ca tego ry when extens i ve expe r i ence , i n comb i nat i on w i th spec i a l ca re i n p l acemen t , c l ea r l y demons t ra tes that t he i r s e t t l ement behav i or i s p red i ctab l e ) . F i l l s con s t ructed of othe r ma te r i a l s , s uch as f i ne- g ra i ned s o i l s o r coa rse- g ra i ned s o i l s hav i ng pe rmea b i l i ty l es s than 0 . 002 fee t pe r m i nute , s hou l d be eva l uated on the bas i s of ana l ys i s of t he comp l e ted f i l l , i nc l ud i ng tes t i ng of und i s tu rbed s amp l es of t he comp l e ted f i l l and unde r l y i ng s o i l . A l though l aboratory tes ts of s t rength and comp res s i b i l i ty can be pe rformed on compacted s amp l es of f i l l ma te r i a l at va r i ous wa te r contents and dens i t i es , t he p rob l em Is to p red i ct when s uch cond i t i ons w i l l ex i s t i n the actua l f i l l . For permeab l e s o i l s , t he f i l l i t se l f dens i f i es read i l y ; but for f i ne- g ra i ned f i l l s o i l s , o r coa rs e- g ra i ned f i l l so i l s hav i ng pe rmeab i l i ty l es s t han 0 . 002 feet per m i nute , the ra te of s t rength bu i l d-up du r i ng and s ubsequent to p l acement cannot be p red i cted , so tha t any s t udy of s l ope s ta b i l i ty and so i l bea r i ng capac i ty p r i or to f i l l comp l e t i on i s necessa r i l y l i m i ted . The p red i ct i on of s e t t l ement us i ng conso l i da t i on tes t res u l ts f rom l abo ra tory- compacted s o i l s amp l es i s a l so i mpos s i b l e . Afte r comp l e t i on of t he f i l l and befo re cons t ruct i on of s t ructu res the reon , t he s t rength and comp res s i b i l i ty p rope rt i es s hou l d be de te rm i ned by l abo ratory tes t s on und i s tu rbe d samp l es of t he f i l l . 1ASTM Des i gna t i on D 1 587-58T , Ten ta t i ve Me t hod for Th i n-Wa l l ed Tube Samp l i ng of So i l s , Ph i l ade l ph i a : Ame r i can Soc i e ty for Tes t i n g and Ma te r i a l s .
Pa ge 20 S upp l emen ta ry I nforma t i on I f t he f i l l i s 1 0 fee t or l es s i n t h i ckness and the d ry dens i ty i s a t l eas t 90 percen t of the maximum obta i nab l e in t he ASTM D 1 55 7-58T 1 compact i on tes t , conso l i da t i on tes ts a re unneces sa ry , as on l y l i mi ted set t l emen t w i l l occu r . 2 . 0 ENG I N E ER I NG CONS I DERAT I ONS T he c ri t e r i a recommended i n Sect i on I l l , pp . 5 - 1 4 , a re min i mum requ i rement s wh i ch mus t be s a t i s f i ed i n t he eva l ua t i on of hyd rau l i c f i l l s . Th i s sect i on i nc l udes exp l anatory commen t s def i n i ng some l i m i t s of app l i ca b i l i ty of t he recommenda t i ons . An eng i nee r i ng ana l ys i s of an t i c i pa ted sett l emen t i s requ i red on a l l hyd ra u l i c-f i l l p roj ects . The resu l t s of l abora to ry conso l i da t i on tes t s on und i s tu rbed samp l es of t he under l y i n g f i ne- g ra i ned na t u ra l s o i l s and the comp l e ted f i l l a re requ i red to dete rm i ne t he t i me s e t t l ement p rope rt i es . The s e t t l ement of s t ructu res and t he f i l l su rface can be de te rm i ned f rom ca l cu l a t i ons of t he chan ge i n s t ress i n t he s o i l mas s and t he accompany i ng comp re s s i on . 2 When t he tota l s e t t l ement ant i c i pa ted exceeds 6 i nches , s e t t l ement p l a tes on the na tura l g round s u rface s hou l d be p rov i ded a t : Po i n t s of g rea tes t l oad app l i ca t i on ( whe re f i l l i s t h i ckes t or a t the l oca t i on of the heav i es t s t ruc t u re) ; l ocat i on of t he t h i ckes t unde r l y i ng comp res s i b l e s t rata ; and l oca tions of s t ruc t u res sens i t i ve to se t t l emen t --a l l po i n ts of potent i a l c r i t i ca l sett l ement p rob l ems . Add i t i ona l p l a tes a t o r nea r the s u rface of t he f i l l a re a l s o he l pf u l i n reco rd i ng the p rog res s of set t l emen t , i nc l ud i ng the effect s of f i l l con s o l i da t i on . The s et t l ement p l a tes p rov i de a mea ns of record i ng t he p rog res s of consol i da t i on of the na t u ra l so i l s . The da ta obse rved f rom t he sett l ement p l a tes can be used to de te rm i ne when the s e t t l ement yet to occu r w i l l not be de t r i men ta l to the cons t ruct i on on the f i l l . 1ASTM Desi gna t i on D 1 557-58T , Ten ta t i ve Methods of Tes t for Mo i s t u re Dens i ty Re l a t i ons of Soi l s us i ng 1 0-Lb Ramme r and 18- l n . D rop , Ph i l ade l ph i a : Ame r i can Soc i e ty for Tes t i ng and Ma t e r i a l s . 2Art . 1 3 , 3 5 , 36 , and 41 of I tem 8 , Append i x D , p . 3 1 , p rov i de a means for mak i ng t h i s dete rm i nat i on .
Page 2 1 Supp l ement a ry I nforma t i on When t he sett l ement ant i c i pated i s 1 2 i nches or mo re , s e r i ous p rob lems w i th regard to s o i l s t rength a re a l so l i ke l y . I n s uch cases , f i e l d measu remen ts of po re-wate r p res s u res are requ i red . P i ezomete rs s hou l d be p rov i ded to meas u re excess po re-wa t e r p res s u res i n the f il l a n d comp res s i b l e under l y i ng na t u ra l s o i l s ; the re s hou l d be an ave ra ge of a t l eas t one p i ezometer pe r 1 00 , 000 squa re feet of f i l l a rea. The so i l eng i nee r , howeve r , may recommend extend i ng the s pac i ng of p i ezomete rs up to an ave rage of one pe r 250 , 000 squa re fee t of f i l l area i f techn i ca l ev i dence f rom bor i ngs , prob i ngs , and the l i ke shows conc l us i ve l y that the f i l l and ex i s t i ng s o i l s a re suff i c i ent l y un i fo rm to be eva l ua ted accu ra te l y w i t h p i ezomete rs s o s pace d . Wheneve r p i ezome t e rs a re requ i red , i t i s neces sa ry tha t some be used a l ong ma rg i ns of t he f i l l , whe re s l ope-stab i l i ty p rob l ems assoc i a ted w i t h weak s ubso i l s a re l i ke l y . The d i s s i pa t i on of excess pore-wate r p res s u re w i l l co i nc i de w i th the prog res s of sett l ement and bu i l d- up of the s o i l s t rength . The refore , t he p l acement of f i l l can be t i me d to e l i m i nate s hea r fa i l ures of the weak unde r l y i ng s o i l s and weak f i l l , wh i ch may occu r as mud waves and s l ope fa i l u res at f i l l ma rg i ns . An eng i nee r i ng ana lys i s of t he s tab i l i ty of f i l l s l opes i s requ i red when the f i l l l oad pe r squa re foot , i nc l ud i ng a f i l l l oad equa l i n effect to p roposed s t ruc t u res the reon , i s greate r than fou r t i mes t he und ra i ned s hear s t rength of t he f i l l o r weakes t unde r l y i ng na tu ra l s o i l . The s l opes of hyd rau l i c f i l l s s hou l d not exceed 1 ve rt i ca l to 4 hor i zonta l un l es s a h i ghe r ra t i o i s j us t i f i ed by an eng i nee r i ng ana l ys i s . When the f i l l l oad i s g rea te r t han fou r t i mes t he s hea r st rength of s o i l s, or when the s l opes a re s teepe r than 1 ve rt i ca l to 4 hor i zon ta l , s l ope fa i l ures may occu r . The eng i nee r i ng s tud i es, when requ i red, s hou l d i nc l ude det a i l s of t he s t rength of the f i l l and unde r l y i ng s o i l s unde r a l l se rv i ce and cons t ruct i on cond i t i ons , ana l ys i s of d r i v i ng forces , eva l ua t i on of res i s tance to s l i d i ng of t he ea rth masses , and effects of seepage forces . 1 A factor of safety- a ga i ns t - fa i l u re unde r a l l 1Art . 3 1 and 41, I tem 8 , Append i x D , p . 3 1 .
Pa ge 22 Supp l emen ta ry I nforma t i on pos s i b i l i t i es of l oad i ng and potent i a l changes i n s o i l and g round wa te r cond i t i ons, dur i ng cons t ruct i on and the l i fe of t he f i l l and s t r uctures t hereon , s hou l d be p rov i ded fo r t he comp l eted f i l l . An added factor of safety i s requ i red when the fa i l ure zone i nc l udes s t ruc t u res , s t reet s , uti l i t i es, o r othe r s uch i mp rovements ra ther than on l y ya rd o.r pa rk a reas. The factor of safety shou l d be h i ghe r when the fa i l u re s u rface pas ses t h rough a ny f i ne- g ra i ned s o i l s t han when it encounte rs on l y coa rse- gra i ned so i l s , because of t he prob l em of accu ra te l y eva l ua t i ng the s hea r s t rength of f i ne g ra i ned s o i l s . The refore , when s t r uctu res or othe r i mp rovemen ts a re i nc l uded i n the fa i l u re zone , a factor of 2.0 shou l d be requ i red when any f i ne- g ra i ned s o i l s a re i nvo l ved , and a factor of 1 .5 s hou l d be used when on l y coa rs e - g ra i ned s o il s a re en coun te red by the fa i l u re s u rface ; when on l y un i mp roved a reas a re i nc l uded , t he factor s hou l d be 1 . 3 for a l l s o i l s . When f i l l s a re exposed to open wa ter , t he i r s l opes w i l l requ i re ca refu l ana l ys i s and des i gn , tak i ng i nto a ccount t he effects of cu r ren t , wave act i on , and s to rm expos ure , w i t h t he des i gn exam i ned for adequacy i n l i ght of expe r i ence i n s i m i l a r s i t ua t i ons . I f t he comp l e ted f i l l has a m i n i mum d ry dens i t y of at l eas t 90 pe rcent of that obta i nab l e i n t he ASTM D 1557-58T tes t , i t s capac i ty i s adequa te for s upport , w i t hout a s hea r fa i l u re , of one and two- s tory res i dent i a l s t ruc t u res on convent i ona l founda t i ons wh i ch i mpose bea r i ng p res s u res of l es s than 2 , 000 psf . I n a l l othe r cases , eva l uat i on of the bea r i ng capac i ty of f i l l and unde r l y i ng s o i l s requ i res an eng i nee r i ng study ut i l i z i ng data f rom s t rength tes ts on und i s tu rbed s amp l es of t he comp l e ted f i l l and ex i s t i ng unde r l y i ng s o i l s , to s upp l emen t the set t l emen t ana l ys i s p rev i ous l y d i s cus sed . The Te rza gh i bea r i ng-capac i ty equat i ons and cha rts 1 may be used . W i th rega rd to bea r i ng capac i ty , a 3 . 0 factor of safe ty a ga i ns t s hea r fa i l u re s hou l d be p rov i ded . A l l cond i t i ons of l oads and so i l p rope rt i es, du r i ng cons t ruct i on and for t he l i fe of the f i l l and s t ructu res t he reon , s hou l d be cons i de red . A h i ghe r factor of s a fe ty a ga i ns t bea r i n g o r s hea r 1A r t . 29 , I tem 8 , Append i x D , p . 3 1 .
Pa ge 23 Supp l ementa ry I n forma t i on fa i l u re unde r a founda t i on i s requ i red t han fo r a s l ope fa i l u re ; one reas on i s t hat l oca l i r regu l a r i ty i n t he s o i l can con t r i bute s i gn i f i ca n t l y to dec reased bea r i ng capac i ty , but s uch l oca l or sma l l a reas of wea k soi l s do not se r i ous l y cont r i bute to s l ope stab i l i t y p rob l ems . U t i l i za t i on of i nd i v i dua l wa te r-s upp l y or s ewa ge-d i sposa l systems s hou l d be cons i de red on l y afte r the i mp ra c t i cab i l i ty of pub l i c or commun i ty sewe rage fac i l i t i es i s estab l i s hed . When use of s uch i nd i v i dua l s ewa ge-d i spos a l systems i s unavo i dab l e, both t he f i l l and the fac i l i t i es s hou l d be des i gned and con s t ructed i n s uch a manne r t hat the eff l uent w i l l d i s s i pate w i thout pon d i ng o r ente r i ng the aqu i f i e r . I n d i v i dua l s ewage-d i spos a l fac i l ities ut i l i z i ng subs urface absorp t i on f i e l ds i n f i l l s hou l d be pe rmit ted on l y when c l ean g rave l s and sands (GW , GP , SW , SP) a re used as f i l l mate r i a l . Use of othe r so i l s i n s uch f i l l s cou l d res u l t i n e r rat i c pe rco l a t i on ra tes , wh i ch may cause unsa t i s factory pe rfo rmance of the s eepa ge f i e l d . W i th c l ean g rave l s and sands , the pe rco l a t i on cha racte r i s t i cs w i l l be re l a t i ve l y un i form. The type of s o i l to be used and c r i ter i a for its p l acement s hou l d be conta i ned i n t he s pec i f i cations . D i fferen t i a l movements due to vo l ume change of the so i l may cause changes i n e l eva t i on of u t i l i ty J i nes , res u l t i ng i n ruptu re of l i nes or undes i ra b l e changes i n s l ope . The i n i t i a l a l i gnment an d s l ope of g ravity-f l ow l ines (for examp l e , f rom sept i c-tank out l et to s eepage-f i eld i n l e t) s hou l d be des i gned to i ns u re s at i sfactory pe rfo rmance even afte r ant i c i pa ted s e tt l emen t occu rs . Spec i a l j o i n ts , a s we l l a s s pec i a l c ra d l i ng , b ridg i ng , o r ext ra-st rength p i pe , may be requ i red for wate r or s ewe r l i nes cons t ructed on f i l l s s ubject to d i ffe rent i a l sett l emen t . U t i l i ty l i nes a t the i r j unct u re w i th st ructu res may requ i re f l ex i b l e connect i ons to accommoda te d i ffe ren t i a l movemen ts . I mp rovement of a comp l e ted f i l l may be necessa ry befo re cons t ruct i on of s t ructu res may p roceed . Su rcharg i ng w i t h an add i t i ona l th i cknes s o f f i l l wh i ch i s removed before const ruct i on o f bu i l d i ng may be ut i l i zed . Con tro l by i nst rumen tat i on s uch as s e t t l ement p l a tes and p i ezome ters i s requ i red . The t i me-se t t l ement p rope rt i es of
Pa ge 24 S upp l ementa ry I nforma t i on t he comp res s i b l e s o i l s ( f i l l and unde r l ying ex i s t i ng) i s requ i red . Sand d ra i n s to exped i te d ra i nage and , consequen t l y , conso l i da t i on may a l so be used to i mp rove a comp l eted f i l l . The actua l sett l ement (tota l , d i ffe rent i a l , and t i me- rate) may va ry f rom tha t p red i cted for a numbe r of reas ons , s uch a s mud-wave forma t i on or exces s i ve ma te r i a l seg rega t i on ; the refore , the ca l cu l a ted va l ues mus t , when app rop r i ate , be rev i sed on t he bas i s of the obse rved data f rom i n sta l l ed s e tt l emen t p l a tes . I nspect i on Cont i nuous i ns pect i on du r i ng p l acement of f i l l mate r i a l s hou l d be requ i red . Much of th i s work i s v i sua l exam i na t i on to a s su re that const ruc t i on i s p rog res s i ng i n conformance w i th the des i gn and s pec i f i ca t i ons. The p revent i on of mud waves i s one respons i b i l i ty of the i n spector (and cont racto r) , s i nce the d i sp l acement of weak and comp res s i ble so i l s w i l l i nf l uence sett l ement and s tab i l i ty p rob l ems , i . e . , th i cke r l aye rs of sof t so i l a re gene ra ted p l us th i n l aye rs , con t r i but i ng to d i ffe rent i a l set t l ement . When mud waves deve l op , the p l acement of f i l l s hou l d be adj us ted to effect even d i s t r i but i on of the d i s p l aced weak mate r i a l s , un l es s the weak mate r i a l can be removed to was te-d i s posa l a reas . I f th i s i s not pos s i b l e , rev i sed s ett l ements ant i c i pa ted s hou l d be dete rm i ned and the ent ire des i gn re-eva l uated; i t may be neces sa ry to comp l e te l y remove the weak so i l s d i s p l aced a s mud waves . I n cases of an t i c i pa ted tota l sett l ement exceed i ng 6 i nches , set t l ement p l a tes a re to be p rov i ded . The gathe r i ng and eva luat i on of data f rom s uch s e t t l emen t p l ates i s part of i ns pect i on . The reco rd i ng of pore-water p res s u res f rom p i ezometers , when p rov i ded , i s anothe r i ns pect i on concern . Forma t i on of mud waves may be e l i m i nated by p l acement of add i t i ona l f i l l on l y when the exces s pore-wate r p res s u re has been reduced to 20 pe rcen t of i ts i n it i a l total or to a l eve l acceptab l e to the s o i l eng i nee r. Pore p res s u res s hou l d t hen be reco rded afte r comp l e t i on of the f i l l , to pe rmit eva l uat i on p r i or to cons t ruct i on of struct u res . - ---
Pa ge 25 S upp l emen ta ry I n fo rma t i on Du r i ng f i l l p l acemen t , t he g ra da t i on of f i l l ma te r i a l s hou l d be de te rm i ned . Seg rega t i on f rom t he end of t he d i s cha rge p i pe s hou l d be avo i ded . Con t i nua l mov i ng of t he d i s cha r ge l i ne i s requ i red except when un i form sand i s be i n g p l aced as a f i l l , to as s u re a reasona b l y un i form f i l l . When t he f i l l i s cons t ructed of coa rs e- g ra i ned ma te r i a l s , i . e . , sa nds and g rave l s , t he compactne s s of the f i l l can be mea s u red by f i e l d�dens i ty tes ts as f i l l cons t ruct i on p roceeds . I n t hese cases , t he re s hou l d be a t l eas t one con tro l tes t for each 3000 cub i c ya rds for f i l l of more t han 1 0 , 000 cub i c-ya rd vo l ume ; one for each 1 000 for 2000 to 1 0 , 000 cub i c ya rds ; and one fo r each 500 for f i l l s under 2000 . Norma l l y , dens i ty tes ts can be pe rformed as soon as a man can wa l k on tha t port i on of t he f i l l , wh i ch may be a day or so afte r p l acement . Fo r f i l l be l ow wate r l eve l , pene t ra t i on tes ts ( ASTH D 1 586-SST) p rovide some meas u re of dens i ty . Cu r rent l y , nuc l ea r me t hods of dete rm i n i n g mo i s t u re con ten t and dens i ty of so i l s a re be i ng deve l oped and tes ted for bot h s u rface mea s u remen t s and meas u remen ts at dep t h . When s uch methods have been s tanda rd i zed and reco rds of expe r i ence comp i l ed , i t s eems app rop r i a te that FHA cons i de r them for a n i ns pect i on too l . When the f i l l i s cons t ructed of f i ne- g ra i ned mate r i a l s o r sands and g rave l s w i th an app rec i ab l e p ropo rt i on of f i nes ( GC, SC) , conso l i da t i on tes ts a re requ i red on und i s t u rbed samp l es of t he comp l e ted f i l l . The bo r i n gs s hou l d be not mo re t han 500 fee t cen te r- to-cen te r i n t he bu i l d i ng a reas . Meas u remen t of re l a t i ve compac tion du r i n g con s t ruct i on i s not requ i red , s i nce t he p rope rt i es of the f i ne- g ra i ned ma te r i a l s chan ge w i t h t i me and l oad i ng . 3 . 0 EX I ST I NG HYDRAUL I C F I L L S T h e eva l ua t i on o f ex i s t i ng hyd ra u l i c f i l l � does n o t l en d i t s e l f to a s e t of s tandard spec i f i ca t i ons; t he p rob l ems a re comp l ex . A maj o r facto r i n de t e rm i n i ng t he adequacy of an ex i s t i n g hyd raul i c f i l l s i s t he deg ree to wh ich conso l i da t i on i n t he unde r l y i n g na t u ra l s o i l and i n t he f i l l i t s e l f has p rogres s e d; the s ta te of
Pa ge 26 S upp l ementa ry I n fo rma t i on conso l i dat i on i s the meas u re of when const ruct i on of st ructures can safe l y p roceed . Ex i st i ng f i l l s hou l d be accepted on l y when a comp rehens i ve i nvest i gat i on i nd i ca tes adequacy for the p roj ect . Ex i st i ng f i l l s shou l d be eva l ua ted cons i stent l y w i th t he c r i te r i a for p ropos ed f i l l s , as p res ented i n p rev i ous pages of t h i s repo rt . The s o i l i nves t i gat i on s hou l d i nc l ude a l l the req u i rements for p roposed f i l l s , as g i ven i n 1 . 0 , pp . 1 6-20 , p l us t he add i tiona l req u i rements that 1 . T he reconnaissance i nc l ude a rev i ew of a ny eng i nee r i n g reco rds perta i n i ng to t he cons t ruct i on of the f i l l and i nves t i ga t i on of the s i te . 2. The re s hou l d be at l eas t two bor i ngs at the s i te , w i t h add i t i ona l bor i n gs t o p rov i de one pe r bu i l d i ng s i te , except when def i n i te ev i dence s hows un i fo rm i ty of cond i t i ons wh i ch w i l l j ust i fy g rea t e r spac i ng , but not to exceed 200 feet . T he eng i nee r i ng c r i te r i a used for acceptance a re t he s ame as for p ropos ed f i l l s , as g i ven i n 2.0, pp . 20-25. The re i s no requ i rement fo r ins pect i on , but a l l i ns pect i on records avai l ab l e conce rn i ng t he fi l l cons t ruct i on s hou l d be ut i l i zed i n app l ying the c r i te r i a fo r acceptance .
Page 2 7 APP END I X A HOW THE STUDY WAS CONDUCTED The Bu i l d i ng Resea rch Adv i sory Boa rd has conducted th i s s tudy of C r i te r i a for Hyd rau l i c F i l l s by appo i n t i ng and u s i ng i n a work i ng s ense a h i gh l y qua l i f i ed Spec i a l Adv i so ry Comm i t tee . Th i s Comm i t tee wa s composed of au thor i t i es on the va r i ous techn i ca l a spec ts of the p rob l em . A s ta temen t of t h e p rob l em a n d a l i s t of ques t i on s we re s en t t o a s e l ec ted g roup of i nd i v i dua l s for con s i de ra t i on and commen t s . The res u l t s of th i s s u rvey we re comp i l ed and s u bm i t ted to the Comm i t tee p r i or to i t s mee t i n g . A two-day meet i ng of the Comm i t tee wa s he l d i n Was h i ngton , D . C . Deta i l ed d i scuss i on of the many a spec t s of the p rob l em en sued . A d raf t of the repo r t wa s p repa red on the ba s i s of d i scus s i on a t th i s mee t i ng . By cor respondence the Comm i t tee ma i n ta i ned con tac t th roughou t p repa ra t i on of the repor t . Each s egmen t of the repor t a nd the repor t a s a who l e rece i ved the a t ten t i on and commen t of the Adv i sory Comm i t tee on the p re l i m i na ry d raf t , and a ga i n p r i or to app rova l f o r t ra n sm i t ta l to the Bu i l d i ng Res ea rch Adv i s o ry Boa rd .
